Thermonuclear plasma with autocatalytic thermomagnetic current amplification by nuclear reactions from fusion neutrons

DOE Office of Scientific and Technical Information (OSTI.GOV)

Winterberg, F.

2006-03-15

It is proposed to use the neutrons released from a deuterium-tritium or deuterium-deuterium fusion reaction to drive thermomagnetic currents in a plasma corona surrounding the fusion plasma through the heating of the corona with nuclear reactions by the neutrons released in the fusion reaction. Because the neutron reaction cross sections are larger for slow neutrons, it is proposed to slow them down in a moderator separated from the hot plasma of the corona, giving the configuration a striking similarity to a heterogeneous nuclear fission reactor. While in a fission reactor the separation makes possible a growing neutron chain reaction, itmore » here makes possible the autocatalytic amplification of the thermomagnetic currents by an increase of the fusion reaction rate through a rise of the plasma pressure by the magnetic pressure of the thermomagnetic currents. This is expected to substantially increase the n{tau} product over its Lawson value.« less

Avalanche proton-boron fusion based on elastic nuclear collisions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eliezer, Shalom; Martinez Val, Josè Maria; Hora, Heinrich

2016-05-15

Recent experiments done at Prague with the 600 J/0.2 ns PALS laser interacting with a layer of boron dopants in a hydrogen enriched target have produced around 10{sup 9} alphas. We suggest that these unexpected very high fusion reactions of proton with {sup 11}B indicate an avalanche multiplication for the measured anomalously high nuclear reaction yields. This can be explained by elastic nuclear collisions in the broad 600 keV energy band, which is coincident with the high nuclear p-{sup 11}B fusion cross section, by the way of multiplication through generation of three secondary alpha particles from a single primarily produced alpha particle.

Experimental measurement of 12C+16O fusion at stellar energies

NASA Astrophysics Data System (ADS)

Fang, X.; Tan, W. P.; Beard, M.; deBoer, R. J.; Gilardy, G.; Jung, H.; Liu, Q.; Lyons, S.; Robertson, D.; Setoodehnia, K.; Seymour, C.; Stech, E.; Vande Kolk, B.; Wiescher, M.; deSouza, R. T.; Hudan, S.; Singh, V.; Tang, X. D.; Uberseder, E.

2017-10-01

The total cross section of the 12C+16O fusion reaction has been measured at low energies to investigate the role of this reaction during late stellar evolution burning phases. A high-intensity oxygen beam, produced by the 5 MV pelletron accelerator at the University of Notre Dame, impinged on a thick, ultrapure graphite target. Protons and γ rays were simultaneously measured in the center-of-mass energy range from 3.64 to 5.01 MeV for singles and from 3.73 to 4.84 MeV for coincidence events, using silicon and Ge detectors. Statistical model calculations were employed to interpret the experimental results. The emergence of a new resonance-like broad structure and a decreasing trend in the S -factor data towards lower energies (opposite to previous data) are found for the 12C+16O fusion reaction. Based on these results the uncertainty range of the reaction rate within the temperature range of late stellar burning environments is discussed.

Stalk model of membrane fusion: solution of energy crisis.

PubMed Central

Kozlovsky, Yonathan; Kozlov, Michael M

2002-01-01

Membrane fusion proceeds via formation of intermediate nonbilayer structures. The stalk model of fusion intermediate is commonly recognized to account for the major phenomenology of the fusion process. However, in its current form, the stalk model poses a challenge. On one hand, it is able to describe qualitatively the modulation of the fusion reaction by the lipid composition of the membranes. On the other, it predicts very large values of the stalk energy, so that the related energy barrier for fusion cannot be overcome by membranes within a biologically reasonable span of time. We suggest a new structure for the fusion stalk, which resolves the energy crisis of the model. Our approach is based on a combined deformation of the stalk membrane including bending of the membrane surface and tilt of the hydrocarbon chains of lipid molecules. We demonstrate that the energy of the fusion stalk is a few times smaller than those predicted previously and the stalks are feasible in real systems. We account quantitatively for the experimental results on dependence of the fusion reaction on the lipid composition of different membrane monolayers. We analyze the dependence of the stalk energy on the distance between the fusing membranes and provide the experimentally testable predictions for the structural features of the stalk intermediates. PMID:11806930

Method of controlling fusion reaction rates

DOEpatents

Kulsrud, Russell M.; Furth, Harold P.; Valeo, Ernest J.; Goldhaber, Maurice

1988-01-01

A method of controlling the reaction rates of the fuel atoms in a fusion reactor comprises the step of polarizing the nuclei of the fuel atoms in a particular direction relative to the plasma confining magnetic field. Fusion reaction rates can be increased or decreased, and the direction of emission of the reaction products can be controlled, depending on the choice of polarization direction.

Method of controlling fusion reaction rates

DOEpatents

Kulsrud, Russell M.; Furth, Harold P.; Valeo, Ernest J.; Goldhaber, Maurice

1988-03-01

A method of controlling the reaction rates of the fuel atoms in a fusion reactor comprises the step of polarizing the nuclei of the fuel atoms in a particular direction relative to the plasma confining magnetic field. Fusion reaction rates can be increased or decreased, and the direction of emission of the reaction products can be controlled, depending on the choice of polarization direction.

Production cross sections of neutron-rich No-263261 isotopes

NASA Astrophysics Data System (ADS)

Li, Jingjing; Li, Cheng; Zhang, Gen; Zhu, Long; Liu, Zhong; Zhang, Feng-Shou

2017-05-01

The fusion excitation functions of No-263249 are studied by using various reaction systems based on the dinuclear system model. The neutron-rich radioactive beam 22O is used to produce neutron-rich nobelium isotopes, and the new neutron-rich isotopes No-263261 are synthesized by 242Pu(22O,3 n )261No , 244Pu(22O,4 n )262No , and 244Pu(22O,3 n )263No reactions, respectively. The corresponding maximum evaporation residue cross sections are 0.628, 4.649, and 1.638 μ b , respectively. The effects of the three processes (capture, fusion, and survival) in the complete fusion reaction are also analyzed. From investigation, a neutron-rich radioactive beam as the projectile and neutron-rich actinide as the target could be a new selection of the projectile-target combination to produce a neutron-rich heavy nuclide.

SU-F-T-140: Assessment of the Proton Boron Fusion Reaction for Practical Radiation Therapy Applications Using MCNP6

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adam, D; Bednarz, B

Purpose: The proton boron fusion reaction is a reaction that describes the creation of three alpha particles as the result of the interaction of a proton incident upon a 11B target. Theoretically, the proton boron fusion reaction is a desirable reaction for radiation therapy applications in that, with the appropriate boron delivery agent, it could potentially combine the localized dose delivery protons exhibit (Bragg peak) and the local deposition of high LET alpha particles in cancerous sites. Previous efforts have shown significant dose enhancement using the proton boron fusion reaction; the overarching purpose of this work is an attempt tomore » validate previous Monte Carlo results of the proton boron fusion reaction. Methods: The proton boron fusion reaction, 11B(p, 3α), is investigated using MCNP6 to assess the viability for potential use in radiation therapy. Simple simulations of a proton pencil beam incident upon both a water phantom and a water phantom with an axial region containing 100ppm boron were modeled using MCNP6 in order to determine the extent of the impact boron had upon the calculated energy deposition. Results: The maximum dose increase calculated was 0.026% for the incident 250 MeV proton beam scenario. The MCNP simulations performed demonstrated that the proton boron fusion reaction rate at clinically relevant boron concentrations was too small in order to have any measurable impact on the absorbed dose. Conclusion: For all MCNP6 simulations conducted, the increase of absorbed dose of a simple water phantom due to the 11B(p, 3α) reaction was found to be inconsequential. In addition, it was determined that there are no good evaluations of the 11B(p, 3α) reaction for use in MCNPX/6 and further work should be conducted in cross section evaluations in order to definitively evaluate the feasibility of the proton boron fusion reaction for use in radiation therapy applications.« less

Membrane fusion triggers rapid degradation of two gamete-specific, fusion-essential proteins in a membrane block to polygamy in Chlamydomonas.

PubMed

Liu, Yanjie; Misamore, Michael J; Snell, William J

2010-05-01

The plasma membranes of gametes are specialized for fusion, yet, once fusion occurs, in many organisms the new zygote becomes incapable of further membrane fusion reactions. The molecular mechanisms that underlie this loss of fusion capacity (block to polygamy) remain unknown. During fertilization in the green alga Chlamydomonas, the plus gamete-specific membrane protein FUS1 is required for adhesion between the apically localized sites on the plasma membranes of plus and minus gametes that are specialized for fusion, and the minus-specific membrane protein HAP2 is essential for completion of the membrane fusion reaction. HAP2 (GCS1) family members are also required for fertilization in Arabidopsis, and for the membrane fusion reaction in the malaria organism Plasmodium berghei. Here, we tested whether Chlamydomonas gamete fusion triggers alterations in FUS1 and HAP2 and renders the plasma membranes of the cells incapable of subsequent fusion. We find that, even though the fusogenic sites support multi-cell adhesions, triploid zygotes are rare, indicating a fusion-triggered block to the membrane fusion reaction. Consistent with the extinction of fusogenic capacity, both FUS1 and HAP2 are degraded upon fusion. The rapid, fusion-triggered cleavage of HAP2 in zygotes is distinct from degradation occurring during constitutive turnover in gametes. Thus, gamete fusion triggers specific degradation of fusion-essential proteins and renders the zygote incapable of fusion. Our results provide the first molecular explanation for a membrane block to polygamy in any organism.

Advanced Fuel Cycles for Fusion Reactors: Passive Safety and Zero-Waste Options

NASA Astrophysics Data System (ADS)

Zucchetti, Massimo; Sugiyama, Linda E.

2006-05-01

Nuclear fusion is seen as a much ''cleaner'' energy source than fission. Most of the studies and experiments on nuclear fusion are currently devoted to the Deuterium-Tritium (DT) fuel cycle, since it is the easiest way to reach ignition. The recent stress on safety by the world's community has stimulated the research on other fuel cycles than the DT one, based on 'advanced' reactions, such as the Deuterium-Helium-3 (DHe) one. These reactions pose problems, such as the availability of 3He and the attainment of the higher plasma parameters that are required for burning. However, they have many advantages, like for instance the very low neutron activation, while it is unnecessary to breed and fuel tritium. The extrapolation of Ignitor technologies towards a larger and more powerful experiment using advanced fuel cycles (Candor) has been studied. Results show that Candor does reach the passive safety and zero-waste option. A fusion power reactor based on the DHe cycle could be the ultimate response to the environmental requirements for future nuclear power plants.

Cherenkov radiation conversion and collection considerations for a gamma bang time/reaction history diagnostic for the NIF.

PubMed

Herrmann, Hans W; Mack, Joseph M; Young, Carlton S; Malone, Robert M; Stoeffl, Wolfgang; Horsfield, Colin J

2008-10-01

Bang time and reaction history measurements are fundamental components of diagnosing inertial confinement fusion (ICF) implosions and will be essential contributors to diagnosing attempts at ignition on the National Ignition Facility (NIF). Fusion gammas provide a direct measure of fusion interaction rate without being compromised by Doppler spreading. Gamma-based gas Cherenkov detectors that convert fusion gamma rays to optical Cherenkov photons for collection by fast recording systems have been developed and fielded at Omega. These systems have established their usefulness in illuminating ICF physics in several experimental campaigns. Bang time precision better than 25 ps has been demonstrated, well below the 50 ps accuracy requirement defined by the NIF system design requirements. A comprehensive, validated numerical study of candidate systems is providing essential information needed to make a down selection based on optimization of sensitivity, bandwidth, dynamic range, cost, and NIF logistics. This paper presents basic design considerations arising from the two-step conversion process from gamma rays to relativistic electrons to UV/visible Cherenkov radiation.

Microfluidics-Based PCR for Fusion Transcript Detection.

PubMed

Chen, Hui

2016-01-01

The microfluidic technology allows the production of network of submillimeter-size fluidic channels and reservoirs in a variety of material systems. The microfluidic-based polymerase chain reaction (PCR) allows automated multiplexing of multiple samples and multiple assays simultaneously within a network of microfluidic channels and chambers that are co-ordinated in controlled fashion by the valves. The individual PCR reaction is performed in nanoliter volume, which allows testing on samples with limited DNA and RNA. The microfluidics devices are used in various types of PCR such as digital PCR and single molecular emulsion PCR for genotyping, gene expression, and miRNA expression. In this chapter, the use of a microfluidics-based PCR for simultaneous screening of 14 known fusion transcripts in patients with leukemia is described.

Understanding the fusion cross section among light nuclei around the Coulomb barrier

NASA Astrophysics Data System (ADS)

Del Zoppo, Antonio; La Cognata, Marco

2017-11-01

In this work we investigate fusion induced by a radioactive 8Li projectile on a 4He gas target, at center-of-mass energies between 0.6 and 5 MeV. The main result is the tendency of the dimensionless fusion cross section to form well visible plateaus alternated to steep rises. This is likely to be the most genuine consequence of the discrete nature of the intervening angular momenta observed so far in fusion reactions right above the Coulomb barrier. A partial-wave analysis, exclusively based on a pure quantal penetration fusion model, identifies a remarkably low-height barrier. Indeed, these plateaus allow enhanced experimental sensitivity to the fusion barrier given that the most barrier-sensitive lowest partial waves are well separated. We expect that the present results for 8Li+4He will promote further investigations of the fusion reaction mechanism between very light ions at energies much below the interaction barrier. For the moment, we believe that understanding the plateau origin in the cross section above the barrier will almost certainly be useful to corroborate the extrapolation to the important astrophysical region below the Coulomb barrier, not only in the case of the 8Li+4He fusion but also for other systems, such as the 12C+12C.

Fusion reactions initiated by laser-accelerated particle beams in a laser-produced plasma.

PubMed

Labaune, C; Baccou, C; Depierreux, S; Goyon, C; Loisel, G; Yahia, V; Rafelski, J

2013-01-01

The advent of high-intensity-pulsed laser technology enables the generation of extreme states of matter under conditions that are far from thermal equilibrium. This in turn could enable different approaches to generating energy from nuclear fusion. Relaxing the equilibrium requirement could widen the range of isotopes used in fusion fuels permitting cleaner and less hazardous reactions that do not produce high-energy neutrons. Here we propose and implement a means to drive fusion reactions between protons and boron-11 nuclei by colliding a laser-accelerated proton beam with a laser-generated boron plasma. We report proton-boron reaction rates that are orders of magnitude higher than those reported previously. Beyond fusion, our approach demonstrates a new means for exploring low-energy nuclear reactions such as those that occur in astrophysical plasmas and related environments.

Experimental Test in a Tokamak of Fusion with Spin-Polarized D and 3He

NASA Astrophysics Data System (ADS)

Honig, Arnold; Sandorfi, Andrew

2007-06-01

An experiment to test polarization retention of highly polarized D and 3He fusion fuels prior to their fusion reactions in a tTokamak is in preparation. The fusion reaction rate with 100% vector polarized reactants is expected from simple theory to increase by a factor of 1.5. With presently available polarizations, fusion reaction enhancements of ˜15% are achievable and of significant interest, while several avenues for obtaining higher polarizations are open. The potential for survival of initial fusion fuel polarizations at ˜108 K plasma core temperatures (˜5KeV) throughout the time interval preceding fusion burn was addressed in a seminal paper in 1982. While the positive conclusion from those calculations suggests that reaction enhancements are indeed feasible, this crucial factor has never been tested in a high temperature plasma core because of difficulties in preparation and injection of sufficiently polarized fusion fuels into a high temperature reactorfusion plasma. Our solution to these problems employs a new source of highly polarized D in the form of solid HD which has been developed and used in our laboratories. Solid HD is compatible with fusion physics in view of its simplicity of elemental composition and very long (weeks) relaxation times at 4K temperature, allowing efficient polarization-preserving cold-transfer operations. Containment and polarization of the HD within polymer capsules, similar to those used in inertial confinement fusion (ICF), is an innovation which simplifies the cold-transfer of polarized fuel from the dilution refrigerator polarization-production apparatus to other liquid helium temperature cryostats, for storage, transport and placement into the barrel of a cryogenic pellet gun for firing at high velocity into the reactor. The other polarized fuel partner, 3He, has been prepared as a polarized gas for applications including high-energy polarized targets and magnetic resonance imaging (MRI) scans. It will be introduced into the reactor by loading at high pressure into a thick-walled ICF-type polymer shell for injection into the plasma core with a room temperature injection gun. Based on current experience, polarizations of both D and 3He of ˜55% are projected, producing a fusion yield increase of about 15%. A collaboration is being developed for implementing this experiment at the DIII-D Ttokamak experiment at San Diego, operated by General Atomics for the U.S. Department of Energy. Calculations indicate a 10% fusion yield increase in the 14.6 MeV protons from the D-3He reaction will provide a statistically significant test of polarization retention in the plasma. Injection of the polarized fuels into a 4He or 1H plasma improves the discrimination of the effects of polarized fuels. Details of the HD fuel preparation, of the polarization processes, and of the injection into the plasma will beare presented. If the expected fusion reaction yield increase indicative of polarization retention is detected, a route to significantly improved second generation D-3He fusion would be established, as well as confidence to undertake the more difficult polarization of tritium, which would offer important cost savings and improved prospects of ignition in the ITER program.

Deuterium-lithium plasma as a source of fusion neutrons

NASA Astrophysics Data System (ADS)

Chirkov, A. Yu; Vesnin, V. R.

2017-11-01

The concepts of deuterium-tritium (D-T) fusion neutron source are currently developed for hybrid fusion-fission systems and the waste transmutation ones. The need to use tritium technologies is a deterrent factor in this promising direction of energy production. Potential possibilities of using systems that do not require tritium developments are of a significant interest. A deuterium-deuterium (D-D) reaction is considered for the use in demonstration fusion neutron sources. The product of this reaction is tritium, which will burn in the plasma with the emission of fast neutrons. D-D reaction is significantly slower then D-T reaction. Present study shows an increase in neutron yield using a powerful injection of the beam of deuterium atoms. The reactions of the deuterium with lithium isotopes are considered. In some of these reactions, fast neutrons can be obtained. The results of the calculation of the neutron yield from the deuterium lithium plasma are discussed. The estimates of the parameters needed for the realization of a source of fusion neutrons are presented.

Engineering a self-sufficient Mycobacterium tuberculosis CYP130 by gene fusion with the reductase-domain of CYP102A1 from Bacillus megaterium.

PubMed

Ortega Ugalde, Sandra; Luirink, Rosa A; Geerke, Daan P; Vermeulen, Nico P E; Bitter, Wilbert; Commandeur, Jan N M

2018-03-01

CYP130 belongs to the subset of cytochrome P450s from Mycobacterium tuberculosis (Mtb) that have been structurally characterized. Despite several efforts for its functional characterization, CYP130 is still considered an orphan enzyme for which no endogenous or exogenous substrate has been identified. In addition, functional redox-partners for CYP130 have not been clearly established yet, hampering the elucidation of its physiological role. In the present study, a catalytically active fusion protein involving CYP130 and the NADPH reductase-domain of CYP102A1 from Bacillus megaterium was created. By screening a panel of known substrates of human P450s, dextromethorphan N-demethylation was identified as a reaction catalyzed by CYP130. The fusion enzyme showed higher catalytic activity, when compared to CYP130 reconstituted with a selection of non-native redox-partners. Molecular dynamics simulation studies based on the crystal structure of CYP130 revealed two primary docking poses of dextromethorphan within the active site consistent with the experimentally observed N-demethylation reaction during the entire molecular dynamics simulation. The dextromethorphan N-demethylation reaction was strongly inhibited by azole-drugs and maybe applied to identify mechanism-based inhibitors of CYP130. Furthermore, the present active CYP130-fusion protein may facilitate the identification of endogenous substrates from Mtb. Copyright © 2017 Elsevier Inc. All rights reserved.

Application of Advanced Nuclear Emulsion Technique to Fusion Neutron Diagnostics

NASA Astrophysics Data System (ADS)

Nakayama, Y.; Tomita, H.; Morishima, K.; Yamashita, F.; Hayashi, S.; Cheon, MunSeong; Isobe, M.; Ogawa, K.; Naka, T.; Nakano, T.; Nakamura, M.; Kawarabayashi, J.; Iguchi, T.; Ochiai, K.

In order to measure the 2.5 MeV neutrons produced by DD nuclear fusion reactions, we have developed a compact neutron detector based on nuclear emulsion. After optimization of development conditions, we evaluated the response of the detector to an accelerator-based DD neutron source. The absolute efficiency at an energy of 2.5 MeV was estimated to be (4.1±0.2)×10-6 tracks/neutron.

Survival-mediated capture and fusion cross sections for heavy-element synthesis

NASA Astrophysics Data System (ADS)

Yao, L.; Loveland, W.

2018-01-01

The cross section for producing a heavy evaporation residue σEVR in a fusion reaction can be written as a product of three nonseparable factors, i.e., the capture cross section, the fusion probability PCN, and the survival probability Wsur. Each of these factors is dependent on the spin. However, one must remember that the Wsur term is zero or very small for higher spin values, thus effectively limiting the capture and fusion terms. For a series of ˜287 reactions leading to heavy evaporation residues with ZCN≤110 , we point out the implications of this fact for capture cross sections for heavy element formation reactions. From a comparison of calculated and measured evaporation residue cross sections we deduce values of the fusion probability PCN for some of these reactions.

Status of DEMO-FNS development

NASA Astrophysics Data System (ADS)

Kuteev, B. V.; Shpanskiy, Yu. S.; DEMO-FNS Team

2017-07-01

Fusion-fission hybrid facility based on superconducting tokamak DEMO-FNS is developed in Russia for integrated commissioning of steady-state and nuclear fusion technologies at the power level up to 40 MW for fusion and 400 MW for fission reactions. The project status corresponds to the transition from a conceptual design to an engineering one. This facility is considered, in RF, as the main source of technological and nuclear science information, which should complement the ITER research results in the fields of burning plasma physics and control.

Pulse-density modulation control of chemical oscillation far from equilibrium in a droplet open-reactor system.

PubMed

Sugiura, Haruka; Ito, Manami; Okuaki, Tomoya; Mori, Yoshihito; Kitahata, Hiroyuki; Takinoue, Masahiro

2016-01-20

The design, construction and control of artificial self-organized systems modelled on dynamical behaviours of living systems are important issues in biologically inspired engineering. Such systems are usually based on complex reaction dynamics far from equilibrium; therefore, the control of non-equilibrium conditions is required. Here we report a droplet open-reactor system, based on droplet fusion and fission, that achieves dynamical control over chemical fluxes into/out of the reactor for chemical reactions far from equilibrium. We mathematically reveal that the control mechanism is formulated as pulse-density modulation control of the fusion-fission timing. We produce the droplet open-reactor system using microfluidic technologies and then perform external control and autonomous feedback control over autocatalytic chemical oscillation reactions far from equilibrium. We believe that this system will be valuable for the dynamical control over self-organized phenomena far from equilibrium in chemical and biomedical studies.

Radiation effect of neutrons produced by D-D side reactions on a D-3He fusion reactor

NASA Astrophysics Data System (ADS)

Bahmani, J.

2017-04-01

One of the most important characteristics in D-3He fusion reactors is neutron production via D-D side reactions. The neutrons can activate structural material, degrading them and ultimately converting them into high-level radioactive waste, while it is really costly and difficult to remove them. The neutrons from a fusion reactor could also be used to make weapons-grade nuclear material, rendering such types of fusion reactors a serious proliferation hazard. A related problem is the presence of radioactive elements such as tritium in D-3He plasma, either as fuel for or as products of the nuclear reactions; substantial quantities of radioactive elements would not only pose a general health risk, but tritium in particular would also be another proliferation hazard. The problems of neutron radiation and radioactive element production are especially interconnected because both would result from the D-D side reaction. Therefore, the presentation approach for reducing neutrons via D-D nuclear side reactions in a D-3He fusion reactor is very important. For doing this research, energy losses and neutron power fraction in D-3He fusion reactors are investigated. Calculations show neutrons produced by the D-D nuclear side reaction could be reduced by changing to a more 3He-rich fuel mixture, but then the bremsstrahlung power loss fraction would increase in the D-3He fusion reactor.

The DD Cold Fusion-Transmutation Connection

NASA Astrophysics Data System (ADS)

Chubb, Talbot A.

2005-12-01

LENR theory must explain dd fusion, alpha-addition transmutations, radiationless nuclear reactions, and three-body nuclear particle reactions. Reaction without radiation requires many-body D Bloch+ periodicity in both location and internal structure dependencies. Electron scattering leads to mixed quantum states. The radiationless dd fusion reaction is 2-D Bloch+ -> {}4 He Bloch2+. Overlap between {}4 He Bloch2+ and surface Cs leads to alpha absorption. In the Iwamura et al. studies active deuterium is created by scattering at diffusion barriers.

Systematic investigations of deep sub-barrier fusion reactions using an adiabatic approach

NASA Astrophysics Data System (ADS)

Ichikawa, Takatoshi

2015-12-01

Background: At extremely low incident energies, unexpected decreases in fusion cross sections, compared to the standard coupled-channels (CC) calculations, have been observed in a wide range of fusion reactions. These significant reductions of the fusion cross sections are often referred to as the fusion hindrance. However, the physical origin of the fusion hindrance is still unclear. Purpose: To describe the fusion hindrance based on an adiabatic approach, I propose a novel extension of the standard CC model by introducing a damping factor that describes a smooth transition from sudden to adiabatic processes, that is, the transition from the separated two-body to the united dinuclear system. I demonstrate the performance of this model by systematically investigating various deep sub-barrier fusion reactions. Method: I extend the standard CC model by introducing a damping factor into the coupling matrix elements in the standard CC model. This avoids double counting of the CC effects, when two colliding nuclei overlap one another. I adopt the Yukawa-plus-exponential (YPE) model as a basic heavy ion-ion potential, which is advantageous for a unified description of the one- and two-body potentials. For the purpose of these systematic investigations, I approximate the one-body potential with a third-order polynomial function based on the YPE model. Results: Calculated fusion cross sections for the medium-heavy mass systems of 64Ni+64Ni , 58Ni+58Ni , and 58Ni+54Fe , the medium-light mass systems of 40Ca+40Ca , 48Ca+48Ca , and 24Mg+30Si , and the mass-asymmetric systems of 48Ca+96Zr and 16O+208Pb are consistent with the experimental data. The astrophysical S factor and logarithmic derivative representations of these are also in good agreement with the experimental data. The values obtained for the individual radius and diffuseness parameters in the damping factor, which reproduce the fusion cross sections well, are nearly equal to the average value for all the systems. Conclusions: Since the results calculated with the damping factor are in excellent agreement with the experimental data in all systems, I conclude that a coordinate-dependent coupling strength is responsible for the fusion hindrance. In all systems, the potential energies at the touching point VTouch strongly correlate with the incident threshold energies for which the fusion hindrance starts to emerge, except for the medium-light mass systems.

A D-D/D-T fusion reaction based neutron generator system for liver tumor BNCT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koivunoro, H.; Lou, T.P.; Leung, K. N.

2003-04-02

Boron-neutron capture therapy (BNCT) is an experimental radiation treatment modality used for highly malignant tumor treatments. Prior to irradiation with low energetic neutrons, a 10B compound is located selectively in the tumor cells. The effect of the treatment is based on the high LET radiation released in the {sup 10}B(n,{alpha}){sup 7}Li reaction with thermal neutrons. BNCT has been used experimentally for brain tumor and melanoma treatments. Lately applications of other severe tumor type treatments have been introduced. Results have shown that liver tumors can also be treated by BNCT. At Lawrence Berkeley National Laboratory, various compact neutron generators based onmore » D-D or D-T fusion reactions are being developed. The earlier theoretical studies of the D-D or D-T fusion reaction based neutron generators have shown that the optimal moderator and reflector configuration for brain tumor BNCT can be created. In this work, the applicability of 2.5 MeV neutrons for liver tumor BNCT application was studied. The optimal neutron energy for external liver treatments is not known. Neutron beams of different energies (1eV < E < 100 keV) were simulated and the dose distribution in the liver was calculated with the MCNP simulation code. In order to obtain the optimal neutron energy spectrum with the D-D neutrons, various moderator designs were performed using MCNP simulations. In this article the neutron spectrum and the optimized beam shaping assembly for liver tumor treatments is presented.« less

Coupled-channel analyses on 16O + 147,148,150,152,154Sm heavy-ion fusion reactions

NASA Astrophysics Data System (ADS)

Erol, Burcu; Yılmaz, Ahmet Hakan

2018-02-01

Heavy-ion collisons are typically characterized by the presence of many open reaction channels. In the energies around the Coulomb barrier, the main processes are elastic scattering, inelastic excitations of low-lying modes and fusion operations of one or two nuclei. The fusion process is generally defined as the effect of one-dimensional barrier penetration model, taking scattering potential as the sum of Coulomb and proximity potential. We have performed heay-ion fusion reactions with coupled-channel (CC) calculations. Coupled-channel formalism is carried out under barrier energy in heavy-ion fusion reactions. In this work fusion cross sections have been calculated and analyzed in detail for the five systems 16O + 147,148,150,152,154sm in the framework of coupled-channel approach (using the codes CCFUS and CCDEF) and Wong Formula. Calculated results are compared with experimental data, CC calculations using code CCFULL and with the cross section datas taken from `nrv'. CCDEF, CCFULL and Wong Formula explains the fusion reactions of heavy-ions very well, while using the scattering potential as WOODS-SAXON volume potential with Akyuz-Winther parameters. It was observed that AW potential parameters are able to reproduce the experimentally observed fusion cross sections reasonably well for these systems. There is a good agreement between the calculated results with the experimental and nrv[8] results.

Formation of Neutron-Enriched Heavy and Superheavy Nuclei in Fusion Reactions

NASA Astrophysics Data System (ADS)

Karpov, A. V.; Rachkov, V. A.; Saiko, V. V.

2018-05-01

The formation of new isotopes of heavy and superheavy elements in the fusion of neutron-enriched projectiles with actinide targets is discussed. Cross sections for the formation of evaporation residues in fusion reactions is predicted for several combinations of colliding nuclei.

Possibilities of production of transfermium nuclei in complete fusion reactions with radioactive beams

NASA Astrophysics Data System (ADS)

Hong, Juhee; Adamian, G. G.; Antonenko, N. V.

2017-07-01

The possibilities of direct production of new isotopes of transfermium nuclei 261,263,264No, 264Lr263, 263,264,266,268Rf, 265Db264, and 267,268,270,272Sg are studied in various asymmetric hot fusion-evaporation reactions with radioactive beams. The optimal reaction partners and conditions for the synthesis of new isotopes are suggested. The products of the suggested reactions can fill a gap of unknown isotopes between the isotopes of heaviest nuclei obtained in the x n evaporation channels of the cold and hot complete fusion reactions with the stable beams.

High energy primary knock-on process in metal deuterium systems initiated by bombardment with noble gas ions

NASA Astrophysics Data System (ADS)

Gann, V. V.; Tolstolutskaya, G. D.

2008-08-01

An experimental study confirms the possibility of nuclear fusion reactions initiating in metal-deuterium targets by bombarding them with ions that are not the reagents of the fusion reaction, in particular, with noble gas ions. The yields of (d,d) and (d,t) reactions were measured as functions of energy (0.4-3.2 MeV) and mass of incident ions (He +, Ne +, Ar +, Kr + and Xe +). Irradiation by heavy ions produced a number of energetic deuterium atoms in the deuteride and deuterium + tritium metal targets. At ion energies of ˜0.1-1 MeV the d-d reaction yields are relatively high. A model of nuclear fusion reaction cross-sections in atomic collision cascades initiated by noble gas ion beam in metal-deuterium target is developed. The method for calculation tritium or deuterium recoil fluxes and the yield of d-d fusion reaction in subsequent collisions was proposed. It was shown that D(d,p)t and D(t,n) 4He reactions mainly occur in energy region of the recoiled D-atom from 10 keV to 250 keV. The calculated probabilities of d-d and d-t fusion reactions were found to be in a good agreement with the experimental data.

Intense fusion neutron sources

NASA Astrophysics Data System (ADS)

Kuteev, B. V.; Goncharov, P. R.; Sergeev, V. Yu.; Khripunov, V. I.

2010-04-01

The review describes physical principles underlying efficient production of free neutrons, up-to-date possibilities and prospects of creating fission and fusion neutron sources with intensities of 1015-1021 neutrons/s, and schemes of production and application of neutrons in fusion-fission hybrid systems. The physical processes and parameters of high-temperature plasmas are considered at which optimal conditions for producing the largest number of fusion neutrons in systems with magnetic and inertial plasma confinement are achieved. The proposed plasma methods for neutron production are compared with other methods based on fusion reactions in nonplasma media, fission reactions, spallation, and muon catalysis. At present, intense neutron fluxes are mainly used in nanotechnology, biotechnology, material science, and military and fundamental research. In the near future (10-20 years), it will be possible to apply high-power neutron sources in fusion-fission hybrid systems for producing hydrogen, electric power, and technological heat, as well as for manufacturing synthetic nuclear fuel and closing the nuclear fuel cycle. Neutron sources with intensities approaching 1020 neutrons/s may radically change the structure of power industry and considerably influence the fundamental and applied science and innovation technologies. Along with utilizing the energy produced in fusion reactions, the achievement of such high neutron intensities may stimulate wide application of subcritical fast nuclear reactors controlled by neutron sources. Superpower neutron sources will allow one to solve many problems of neutron diagnostics, monitor nano-and biological objects, and carry out radiation testing and modification of volumetric properties of materials at the industrial level. Such sources will considerably (up to 100 times) improve the accuracy of neutron physics experiments and will provide a better understanding of the structure of matter, including that of the neutron itself.

Accelerator based fusion reactor

NASA Astrophysics Data System (ADS)

Liu, Keh-Fei; Chao, Alexander Wu

2017-08-01

A feasibility study of fusion reactors based on accelerators is carried out. We consider a novel scheme where a beam from the accelerator hits the target plasma on the resonance of the fusion reaction and establish characteristic criteria for a workable reactor. We consider the reactions d+t\\to n+α,d+{{}3}{{H}\\text{e}}\\to p+α , and p+{{}11}B\\to 3α in this study. The critical temperature of the plasma is determined from overcoming the stopping power of the beam with the fusion energy gain. The needed plasma lifetime is determined from the width of the resonance, the beam velocity and the plasma density. We estimate the critical beam flux by balancing the energy of fusion production against the plasma thermo-energy and the loss due to stopping power for the case of an inert plasma. The product of critical flux and plasma lifetime is independent of plasma density and has a weak dependence on temperature. Even though the critical temperatures for these reactions are lower than those for the thermonuclear reactors, the critical flux is in the range of {{10}22}-{{10}24}~\\text{c}{{\\text{m}}-2}~{{\\text{s}}-1} for the plasma density {ρt}={{10}15}~\\text{c}{{\\text{m}}-3} in the case of an inert plasma. Several approaches to control the growth of the two-stream instability are discussed. We have also considered several scenarios for practical implementation which will require further studies. Finally, we consider the case where the injected beam at the resonance energy maintains the plasma temperature and prolongs its lifetime to reach a steady state. The equations for power balance and particle number conservation are given for this case.

Fusion yield: Guderley model and Tsallis statistics

NASA Astrophysics Data System (ADS)

Haubold, H. J.; Kumar, D.

2011-02-01

The reaction rate probability integral is extended from Maxwell-Boltzmann approach to a more general approach by using the pathway model introduced by Mathai in 2005 (A pathway to matrix-variate gamma and normal densities. Linear Algebr. Appl. 396, 317-328). The extended thermonuclear reaction rate is obtained in the closed form via a Meijer's G-function and the so-obtained G-function is represented as a solution of a homogeneous linear differential equation. A physical model for the hydrodynamical process in a fusion plasma-compressed and laser-driven spherical shock wave is used for evaluating the fusion energy integral by integrating the extended thermonuclear reaction rate integral over the temperature. The result obtained is compared with the standard fusion yield obtained by Haubold and John in 1981 (Analytical representation of the thermonuclear reaction rate and fusion energy production in a spherical plasma shock wave. Plasma Phys. 23, 399-411). An interpretation for the pathway parameter is also given.

Breakup and n -transfer effects on the fusion reactions Li,76+Sn,119120 around the Coulomb barrier

NASA Astrophysics Data System (ADS)

Fisichella, M.; Shotter, A. C.; Figuera, P.; Lubian, J.; Di Pietro, A.; Fernandez-Garcia, J. P.; Ferreira, J. L.; Lattuada, M.; Lotti, P.; Musumarra, A.; Pellegriti, M. G.; Ruiz, C.; Scuderi, V.; Strano, E.; Torresi, D.; Zadro, M.

2017-03-01

This paper presents values of complete fusion cross sections deduced from activation measurements for the reactions 6Li+120Sn and 7Li+119Sn , and for a projectile energy range from 17.5 to 28 MeV in the center-of-mass system. A new deconvolution analysis technique is used to link the basic activation data to the actual fusion excitation function. The complete fusion cross sections above the barrier are suppressed by about 70 % and 85 % with respect to the universal fusion function, used as a standard reference, in the 6Li and 7Li induced reactions, respectively. From a comparison of the excitation functions of the two systems at energies below the barrier, no significant differences can be observed, despite the two systems have different n -transfer Q values. This observation is supported by the results of coupled reaction channels (CRC) calculations.

Experimental study of nuclear fusion reactions in muonic molecular systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bogdanova, L. N., E-mail: ludmila@itep.ru

2013-03-15

Since the pioneering discovery of the muon catalysis by Alvarez [L. W. Alvarez, K. Brander, F. S. Crawford, et al., Phys. Rev. 105, 1127 (1957)], considerable efforts were aimed at observation of various fusion processes. Results of these studies facilitated understanding the properties of lightest nuclei and dynamics of low-energy fusion reactions. There still remain unsolved theoretical and experimental problems, especially in case of pt fusion.

Magnetized Target Fusion in Advanced Propulsion Research

NASA Technical Reports Server (NTRS)

Cylar, Rashad

2003-01-01

The Magnetized Target Fusion (MTF) Propulsion lab at NASA Marshall Space Flight Center in Huntsville, Alabama has a program in place that has adopted to attempt to create a faster, lower cost and more reliable deep space transportation system. In this deep space travel the physics and development of high velocity plasma jets must be understood. The MTF Propulsion lab is also in attempt to open up the solar system for human exploration and commercial use. Fusion, as compared to fission, is just the opposite. Fusion involves the light atomic nuclei combination to produce denser nuclei. In the process, the energy is created by destroying the mass according to the distinguished equation: E = mc2 . Fusion energy development is being pursued worldwide as a very sustainable form of energy that is environmentally friendly. For the purposes of space exploration fusion reactions considered include the isotopes of hydrogen-deuterium (D2) and tritium (T3). Nuclei have an electrostatic repulsion between them and in order for the nuclei to fuse this repulsion must be overcome. One technique to bypass repulsion is to heat the nuclei to very high temperatures. The temperatures vary according to the type of reactions. For D-D reactions, one billion degrees Celsius is required, and for D-T reactions, one hundred million degrees is sufficient. There has to be energy input for useful output to be obtained form the fusion To make fusion propulsion practical, the mass, the volume, and the cost of the equipment to produce the reactions (generally called the reactor) need to be reduced by an order of magnitude or two from the state-of-the-art fusion machines. Innovations in fusion schemes are therefore required, especially for obtaining thrust for propulsive applications. Magnetized target fusion (MTF) is one of the innovative fusion concepts that have emerged over the last several years. MSFC is working with Los Alamos National Laboratory and other research groups in studying the underlying principles involved in MTF. Magnetized Target Fusion is an attempt to combine MCF (magnetic confinement fusion) for energy confinement and ICF (inertial confinement fusion) for efficient compression heating and wall free containment of the fusing plasma. It also seeks to combine the best features to these two main commonplace approaches to fusion.

Nuclear astrophysics at Gran Sasso Laboratory: the LUNA experiment

NASA Astrophysics Data System (ADS)

Cavanna, Francesca

2018-05-01

LUNA is an experimental approach for the study of nuclear fusion reactions based on an underground accelerator laboratory. Aim of the experiment is the direct measurement of the cross section of nuclear reactions relevant for stellar and primordial nucleosynthesis. In the following the latest results and the future goals will be presented.

SOLVING THE STAND-OFF PROBLEM FOR MAGNETIZED TARGET FUSION: PLASMA STREAMS AS DISPOSABLE ELECTRODES, PLUS A LOCAL SPHERICAL BLANKET

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ryutov, D D; Thio, Y F

In a fusion reactor based on the Magnetized Target Fusion approach, the permanent power supply has to deliver currents up to a few mega-amperes to the target dropped into the reaction chamber. All the structures situated around the target will be destroyed after every pulse and have to be replaced at a frequency of 1 to 10 Hz. In this paper, an approach based on the use of spherical blanket surrounding the target, and pulsed plasma electrodes connecting the target to the power supply, is discussed. A brief physic analysis of the processes associated with creation of plasma electrodes ismore » discussed.« less

Simulations of inertial confinement fusion driven by a novel synchrotron-radiation-based x-ray igniter

NASA Astrophysics Data System (ADS)

Shlyaptsev, Vyacheslav N.; Tatchyn, Roman O.

2004-01-01

The advantages and challenges of using a powerful x-ray source for the fast ignition of compressed Inertial Confinement Fusion (ICF) targets have been considered. The requirements for such a source together with the optics to focus the x-rays onto compressed DT cores lead to a conceptual design based on Energy Recovery Linacs (ERLs) and long wigglers to produce x-ray pulses with the appropriate phase space properties. A comparative assessment of the parameters of the igniter system indicates that the technologies for building it, although expensive, are physically achievable. Our x-ray fast ignition (XFI) scheme requires substantially smaller energy for the initiation of nuclear fusion reactions than other methods.

Role of input angular momentum and target deformation on the incomplete-fusion dynamics in the 16O+154Sm system at ELab=6.1 MeV/nucleon

NASA Astrophysics Data System (ADS)

Singh, D.; Linda, Sneha B.; Giri, Pankaj K.; Mahato, Amritraj; Tripathi, R.; Kumar, Harish; Ansari, M. Afzal; Sathik, N. P. M.; Ali, Rahbar; Kumar, R.; Muralithar, S.; Singh, R. P.

2018-06-01

Spin distributions of nine evaporation residues 164Yb(x n ) , 163Tm(p x n ) , Er,167168(2 p x n ) , Ho-161163(α p x n ) , 164Dy(α 2 p x n ) , and 160Dy(2 α x n ) produced through complete- and incomplete-fusion reactions have been measured in the system 16O+154Sm at projectile energy =6.1 MeV /nucleon using the in-beam charged-particle (Z =1 ,2 )-γ-ray coincidence technique. The results indicate the occurrence of incomplete fusion involving the breakup of 16O into 4He+12C and/or 8Be+8Be followed by fusion of one of the fragments with target nucleus 154Sm. The pattern of measured spin distributions of the evaporation residues produced through complete and incomplete fusion are found to be entirely different from each other. It has been observed from these present results that the mean input angular momentum for the evaporation residues produced through complete fusion is relatively lower than that of evaporation residues produced through incomplete-fusion reactions. The pattern of feeding intensity of evaporation residues populated through complete- and incomplete-fusion reactions has also been studied. The evaporation residues populated through complete-fusion channels are strongly fed over a broad spin range and widely populated, while evaporation residues populated through incomplete-fusion reactions are found to have narrow range feeding only for high spin states. Comparison of present results with earlier data suggests that the value of mean input angular momentum is relatively higher for a deformed target and more mass asymmetric system than that of a spherical target and less mass asymmetric system by using the same projectile and the same energy. Thus, present results indicate that the incomplete-fusion reactions not only depend on the mass asymmetry of the system, but also depend on the deformation of the target.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baylor, Larry R.; Meitner, Steven J.

Magnetically confined fusion plasmas generate energy from deuterium-tritium (DT) fusion reactions that produce energetic 3.5 MeV alpha particles and 14 MeV neutrons. Since the DT fusion reaction rate is a strong function of plasma density, an efficient fueling source is needed to maintain high plasma density in such systems. Energetic ions in fusion plasmas are able to escape the confining magnetic fields at a much higher rate than the fusion reactions occur, thus dictating the fueling rate needed. These lost ions become neutralized and need to be pumped away as exhaust gas to be reinjected into the plasma as fuelmore » atoms.The technology to fuel and pump fusion plasmas has to be inherently compatible with the tritium fuel. An ideal holistic solution would couple the pumping and fueling such that the pump exhaust is directly fed back into pellet formation without including impurity gases. This would greatly reduce the processing needs for the exhaust. Concepts to accomplish this are discussed along with the fueling and pumping needs for a DT fusion reactor.« less

Role of hexadecapole deformation of projectile 28Si in heavy-ion fusion reactions near the Coulomb barrier

NASA Astrophysics Data System (ADS)

Kaur, Gurpreet; Hagino, K.; Rowley, N.

2018-06-01

The vast knowledge regarding the strong influence of quadrupole deformation β2 of colliding nuclei in heavy-ion sub-barrier fusion reactions inspires a desire to quest the sensitivity of fusion dynamics to higher order deformations, such as β4 and β6 deformations. However, such studies have rarely been carried out, especially for deformation of projectile nuclei. In this article, we investigated the role of β4 of the projectile nucleus in the fusion of the 28Si+92Zr system. We demonstrated that the fusion barrier distribution is sensitive to the sign and value of the β4 parameter of the projectile, 28Si, and confirmed that the 28Si nucleus has a large positive β4. This study opens an indirect way to estimate deformation parameters of radioactive nuclei using fusion reactions, which is otherwise difficult because of experimental constraints.

Nuclear fusion of advanced fuels using converging focused ion beams

NASA Astrophysics Data System (ADS)

Egle, Brian James

The Six Ion Gun Fusion Experiment (SIGFE) was designed and built to investigate a possible avenue to increase the reaction rate efficiency of the D-D and D-3He nuclear fusion reactions in Inertial Electrostatic Confinement (IEC) devices to the levels required for several non-electric applications of nuclear fusion. The SIGFE is based on the seminal IEC experiment published by Hirsch in 1967, and is the first experiment to recreate the results and unique features of the Hirsch device. The SIGFE used six identical ion beams to focus and converge deuterium and helium-3 ions into a sphere of less than 2 mm at nearly mono-energetic ion energies up to 150 keV. With improved ion optics and diagnostics, the SIGFE concluded that within the investigated parameter space, the region where the ion beams converged accounted for less than 0.2% of the total D-D fusion reactions. The maximum D-D fusion rates were observed when the ion beams were intentionally defocused to strike the inside surface of the cathode lenses. In this defocused state, the total D-D fusion rate increased when the chamber pressure was decreased. The maximum D-D fusion rate was 4.3 x 107 neutrons per second at a cathode voltage of -130 kV, a total cathode current of 10 mA, and a chamber pressure of 27 mPa. The D and 3He ion beams were produced in six self-contained ion gun modules. The modules were each capable of at least 4 mA of ion current while maintaining a main chamber pressure as low as 13 mPa. The theoretically calculated extractable ion current agreed with the experiment within a factor of 2. A concept was also developed and evaluated for the production of radioisotopes from the 14.7 MeV D-3He fusion protons produced in an IEC device. Monte Carlo simulations of this concept determined that a D-3He fusion rate on the order of 1011 s-1 would be required for an IEC device to produce 1 mCi of the 11C radioisotope.

Solving The Longstanding Problem Of Low-Energy Nuclear Reactions At the Highest Microscopic Level - Final Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Quaglioni, S.

2016-09-22

A 2011 DOE-NP Early Career Award (ECA) under Field Work Proposal (FWP) SCW1158 supported the project “Solving the Long-Standing Problem of Low-Energy Nuclear Reactions at the Highest Microscopic Level” in the five-year period from June 15, 2011 to June 14, 2016. This project, led by PI S. Quaglioni, aimed at developing a comprehensive and computationally efficient framework to arrive at a unified description of structural properties and reactions of light nuclei in terms of constituent protons and neutrons interacting through nucleon-nucleon (NN) and three-nucleon (3N) forces. Specifically, the project had three main goals: 1) arriving at the accurate predictions formore » fusion reactions that power stars and Earth-based fusion facilities; 2) realizing a comprehensive description of clustering and continuum effects in exotic nuclei, including light Borromean systems; and 3) achieving fundamental understanding of the role of the 3N force in nuclear reactions and nuclei at the drip line.« less

Calculation of Formation and Decay of Heavy Compound Nuclei

NASA Astrophysics Data System (ADS)

Cherepanov, E. A.

2001-04-01

The report describes a method for calculating fusion and decay probabilities in reactions leading to the production of transfermium elements. The competition between quasi-fission and fussion is described on the basis of the Dinuclear System Concept (DNSC). The both competition between fusion and quasi-fission and statistical decay of heavy highly fissionable excited compound nuclei is described in an approach based on the Monte-Carlo method.

Role of tunnelling in complete and incomplete fusion induced by 9Be on 169Tm and 187Re targets at around barrier energies

NASA Astrophysics Data System (ADS)

Kharab, Rajesh; Chahal, Rajiv; Kumar, Rajiv

2017-04-01

We have analyzed the complete and incomplete fusion excitation function for 9Be +169Tm, 187Re reactions at around barrier energies using the code PLATYPUS based on classical dynamical model. The quantum mechanical tunnelling correction is incorporated at near and sub barrier energies which significantly improves the matching between the data and prediction.

Anisotropy of the angular distribution of fission fragments in heavy-ion fusion-fission reactions: The influence of the level-density parameter and the neck thickness

NASA Astrophysics Data System (ADS)

Naderi, D.; Pahlavani, M. R.; Alavi, S. A.

2013-05-01

Using the Langevin dynamical approach, the neutron multiplicity and the anisotropy of angular distribution of fission fragments in heavy ion fusion-fission reactions were calculated. We applied one- and two-dimensional Langevin equations to study the decay of a hot excited compound nucleus. The influence of the level-density parameter on neutron multiplicity and anisotropy of angular distribution of fission fragments was investigated. We used the level-density parameter based on the liquid drop model with two different values of the Bartel approach and Pomorska approach. Our calculations show that the anisotropy and neutron multiplicity are affected by level-density parameter and neck thickness. The calculations were performed on the 16O+208Pb and 20Ne+209Bi reactions. Obtained results in the case of the two-dimensional Langevin with a level-density parameter based on Bartel and co-workers approach are in better agreement with experimental data.

Conventional physics can explain cold fusion excess heat

NASA Astrophysics Data System (ADS)

Chubb, S. R.

In 1989, when Fleischmann, Pons and Hawkins (FP), claimed they had created room temperature, nuclear fusion in a solid, a firestorm of controversy erupted. Beginning in 1991, the Office of Naval Research began a decade-long study of the FP excess heat effect. This effort documented the fact that the excess heat that FP observed is the result of a form of nuclear fusion that can occur in solids at reduced temperature, dynamically, through a deuteron (d)+d□4He reaction, without high-energy particles or □ rays. A key reason this fact has not been accepted is the lack of a cogent argument, based on fundamental physical ideas, justifying it. In the paper, this question is re-examined, based on a generalization of conventional energy band theory that applies to finite, periodic solids, in which d's are allowed to occupy wave-like, ion band states, similar to the kinds of states that electrons occupy in ordinary metals. Prior to being experimentally observed, the Ion Band State Theory (IBST) of cold fusion predicted a potential d+d□4He reaction, without high energy particles, would explain the excess heat, the 4He would be found in an unexpected place (outside heat-producing electrodes), and high-loading, x□1, in PdDx, would be required.

Systematic analysis of advanced fusion fuel in inertial fusion energy

NASA Astrophysics Data System (ADS)

Velarde, G.; Eliezer, S.; Henis, Z.; Piera, M.; Martinez-Val, J. M.

1997-04-01

Aneutronic fusion reactions can be considered as the cleanest way to exploit nuclear energy. However, these reactions present in general two main drawbacks.—very high temperatures are needed to reach relevant values of their cross sections—Moderate (and even low) energy yield per reaction. This value is still lower if measured in relation to the Z number of the reacting particles. It is already known that bremsstrahlung overruns the plasma reheating by fusion born charged-particles in most of the advanced fuels. This is for instance the case for proton-boron-11 fusion in a stoichiometric plasma and is also so in lithium isotopes fusion reactions. In this paper, the use of deuterium-tritium seeding is suggested to allow to reach higher burnup fractions of advanced fuels, starting at a lower ignition temperature. Of course, neutron production increases as DT contents does. Nevertheless, the ratio of neutron production to energy generation is much lower in DT-advanced fuel mixtures than in pure DT plasmas. One of the main findings of this work is that some natural resources (as D and Li-7) can be burned-up in a catalytic regime for tritium. In this case, neither external tritium breeding nor tritium storage are needed, because the tritium inventory after the fusion burst is the same as before it. The fusion reactor can thus operate on a pure recycling of a small tritium inventory.

Fusion reaction cross-sections using the Wong model within Skyrme energy density based semiclassical extended Thomas Fermi approach

NASA Astrophysics Data System (ADS)

Kumar, Raj; Sharma, Manoj K.; Gupta, Raj K.

2011-11-01

First, the nuclear proximity potential, obtained by using the semiclassical extended Thomas Fermi (ETF) approach in Skyrme energy density formalism (SEDF), is shown to give more realistic barriers in frozen density approximation, as compared to the sudden approximation. Then, taking advantage of the fact that, in ETF method, different Skyrme forces give different barriers (height, position and curvature), we use the ℓ-summed extended-Wong model of Gupta and collaborators (2009) [1] under frozen densities approximation for calculating the cross-sections, where the Skyrme force is chosen with proper barrier characteristics, not-requiring additional "barrier modification" effects (lowering or narrowing, etc.), for a best fit to data at sub-barrier energies. The method is applied to capture cross-section data from 48Ca + 238U, 244Pu, and 248Cm reactions and to fusion-evaporation cross-sections from 58Ni + 58Ni, 64Ni + 64Ni, and 64Ni + 100Mo reactions, with effects of deformations and orientations of nuclei included, wherever required. Interestingly, whereas the capture cross-sections in Ca-induced reactions could be fitted to any force, such as SIII, SV and GSkI, by allowing a small change of couple of units in deduced ℓ-values at below-barrier energies, the near-barrier data point of 48Ca + 248Cm reaction could not be fitted to ℓ-values deduced for below-barrier energies, calling for a check of data. On the other hand, the fusion-evaporation cross-sections in Ni-induced reactions at sub-barrier energies required different Skyrme forces, representing "modifications of the barrier", for the best fit to data at all incident center-of-mass energies E's, displaying a kind of fusion hindrance at sub-barrier energies. This barrier modification effect is taken into care here by using different Skyrme forces for reactions belonging to different regions of the periodic table. Note that more than one Skyrme force (with identical barrier characteristics) could equally well fit the same data.

Low energy measurements of the 10B(p ,α )7Be reaction

NASA Astrophysics Data System (ADS)

Wiescher, M.; deBoer, R. J.; Görres, J.; Azuma, R. E.

2017-04-01

Background: The 11B(p,2 α ) 4He reaction is being discussed as a prime candidate for advanced aneutronic fusion fuel systems. Particular interest in this reaction has recently emerged for laser driven plasma systems for energy generation and jet-propulsion systems. The lack of long-lived radioactive reaction products has been suggested as the main advantage of proton-boron fusion fuel. However, 19% of natural boron is 10B, with the 10B(p ,α )7Be fusion reaction producing long-lived 7Be as a side product. Purpose: A detailed measurement of the 10B(p ,α )7Be reaction over the critical energy range of hot fusion plasma environments will help to determine the amount of 7Be radioactivity being produced. This information can be used in turn to monitor the actual fusion temperature by offline measurement of the extracted 7Be activity. The goal of the here presented experiment is to expand on the results of earlier experiments, covering a wider energy range of interest for aneutronic plasma fusion applications, including also both 10B(p ,α0)7Be and the 10B(p ,α1)7Be reaction channels. Method: The reaction cross section was measured over a wide energy range from Ep=400 to 1000 keV using particle detection and from Ep=80 to 1440 keV using γ -ray spectroscopic techniques. Reaction α particles were measured at different angles to obtain angular distribution information. The results are discussed in terms of an R -matrix analysis. Results: The cross section data cover a wider energy range than previously investigated and bridge a gap in the previously available data sets. The cross sections show good agreement with previous results in the low energy region and show that the 10B(p ,α0)7Be channel is considerably larger than that of the 10B(p ,α1)7Be channel up to Ep≈1 MeV . Conclusions: The new reaction data provides important new information about the reaction cross section over the entire energy range of plasma fusion facilities. This data, when coupled with previous measurement of the competing 10B(p ,γ )11C reaction, will provide the opportunity for an extensive R -matrix analysis of the rather complex level structure in the 11C compound nucleus system.

Records for conversion of laser energy to nuclear energy in exploding nanostructures

NASA Astrophysics Data System (ADS)

Jortner, Joshua; Last, Isidore

2017-09-01

Table-top nuclear fusion reactions in the chemical physics laboratory can be driven by high-energy dynamics of Coulomb exploding, multicharged, deuterium containing nanostructures generated by ultraintense, femtosecond, near-infrared laser pulses. Theoretical-computational studies of table-top laser-driven nuclear fusion of high-energy (up to 15 MeV) deuterons with 7Li, 6Li and D nuclei demonstrate the attainment of high fusion yields within a source-target reaction design, which constitutes the highest table-top fusion efficiencies obtained up to date. The conversion efficiency of laser energy to nuclear energy (0.1-1.0%) for table-top fusion is comparable to that for DT fusion currently accomplished for 'big science' inertial fusion setups.

Screening effects on 12C+12C fusion reaction

NASA Astrophysics Data System (ADS)

Koyuncu, F.; Soylu, A.

2018-05-01

One of the important reactions for nucleosynthesis in the carbon burning phase in high-mass stars is the 12C+12C fusion reaction. In this study, we investigate the influences of the nuclear potentials and screening effect on astrophysically interesting 12C+12C fusion reaction observables at sub-barrier energies by using the microscopic α–α double folding cluster (DFC) potential and the proximity potential. In order to model the screening effects on the experimental data, a more general exponential cosine screened Coulomb (MGECSC) potential including Debye and quantum plasma cases has been considered in the calculations for the 12C+12C fusion reaction. In the calculations of the reaction observables, the semi-classical Wentzel-Kramers-Brillouin (WKB) approach and coupled channel (CC) formalism have been used. Moreover, in order to investigate how the potentials between 12C nuclei produce molecular cluster states of 24Mg, the normalized resonant energy states of 24Mg cluster bands have been calculated for the DFC potential. By analyzing the results produced from the fusion of 12C+12C, it is found that taking into account the screening effects in terms of MGECSC is important for explaining the 12C+12C fusion data, and the microscopic DFC potential is better than the proximity potential in explaining the experimental data, also considering that clustering is dominant for the structure of the 24Mg nucleus. Supported by the Turkish Science and Research Council (TÜBİTAK) with (117R015)

Neutron counter based on beryllium activation

NASA Astrophysics Data System (ADS)

Bienkowska, B.; Prokopowicz, R.; Scholz, M.; Kaczmarczyk, J.; Igielski, A.; Karpinski, L.; Paducha, M.; Pytel, K.

2014-08-01

The fusion reaction occurring in DD plasma is followed by emission of 2.45 MeV neutrons, which carry out information about fusion reaction rate and plasma parameters and properties as well. Neutron activation of beryllium has been chosen for detection of DD fusion neutrons. The cross-section for reaction 9Be(n, α)6He has a useful threshold near 1 MeV, which means that undesirable multiple-scattered neutrons do not undergo that reaction and therefore are not recorded. The product of the reaction, 6He, decays with half-life T1/2 = 0.807 s emitting β- particles which are easy to detect. Large area gas sealed proportional detector has been chosen as a counter of β-particles leaving activated beryllium plate. The plate with optimized dimensions adjoins the proportional counter entrance window. Such set-up is also equipped with appropriate electronic components and forms beryllium neutron activation counter. The neutron flux density on beryllium plate can be determined from the number of counts. The proper calibration procedure needs to be performed, therefore, to establish such relation. The measurements with the use of known β-source have been done. In order to determine the detector response function such experiment have been modeled by means of MCNP5-the Monte Carlo transport code. It allowed proper application of the results of transport calculations of β- particles emitted from radioactive 6He and reaching proportional detector active volume. In order to test the counter system and measuring procedure a number of experiments have been performed on PF devices. The experimental conditions have been simulated by means of MCNP5. The correctness of simulation outcome have been proved by measurements with known radioactive neutron source. The results of the DD fusion neutron measurements have been compared with other neutron diagnostics.

Modeling and numerical analysis of a magneto-inertial fusion concept with the target created through FRC merging

NASA Astrophysics Data System (ADS)

Li, Chenguang; Yang, Xianjun

2016-10-01

The Magnetized Plasma Fusion Reactor concept is proposed as a magneto-inertial fusion approach based on the target plasma created through the collision merging of two oppositely translating field reversed configuration plasmas, which is then compressed by the imploding liner driven by the pulsed-power driver. The target creation process is described by a two-dimensional magnetohydrodynamics model, resulting in the typical target parameters. The implosion process and the fusion reaction are modeled by a simple zero-dimensional model, taking into account the alpha particle heating and the bremsstrahlung radiation loss. The compression on the target can be 2D cylindrical or 2.4D with the additive axial contraction taken into account. The dynamics of the liner compression and fusion burning are simulated and the optimum fusion gain and the associated target parameters are predicted. The scientific breakeven could be achieved at the optimized conditions.

Inertial Confinement Fusion and the National Ignition Facility (NIF)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ross, P.

2012-08-29

Inertial confinement fusion (ICF) seeks to provide sustainable fusion energy by compressing frozen deuterium and tritium fuel to extremely high densities. The advantages of fusion vs. fission are discussed, including total energy per reaction and energy per nucleon. The Lawson Criterion, defining the requirements for ignition, is derived and explained. Different confinement methods and their implications are discussed. The feasibility of creating a power plant using ICF is analyzed using realistic and feasible numbers. The National Ignition Facility (NIF) at Lawrence Livermore National Laboratory is shown as a significant step forward toward making a fusion power plant based on ICF.more » NIF is the world’s largest laser, delivering 1.8 MJ of energy, with a peak power greater than 500 TW. NIF is actively striving toward the goal of fusion energy. Other uses for NIF are discussed.« less

Spectral broadening of characteristic γ-ray emission peaks from 12C(3He,pγ)14N reactions in fusion plasmas.

PubMed

Tardocchi, M; Nocente, M; Proverbio, I; Kiptily, V G; Blanchard, P; Conroy, S; Fontanesi, M; Grosso, G; Kneupner, K; Lerche, E; Murari, A; Cippo, E Perelli; Pietropaolo, A; Syme, B; Van Eester, D; Gorini, G

2011-11-11

The spectral broadening of characteristic γ-ray emission peaks from the reaction (12)C((3)He,pγ)(14)N was measured in D((3)He) plasmas of the JET tokamak with ion cyclotron resonance heating tuned to the fundamental harmonic of (3)He. Intensities and detailed spectral shapes of γ-ray emission peaks were successfully reproduced using a physics model combining the kinetics of the reacting ions with a detailed description of the nuclear reaction differential cross sections for populating the L1-L8 (14)N excitation levels yielding the observed γ-ray emission. The results provide a paradigm, which leverages knowledge from areas of physics outside traditional plasma physics, for the development of nuclear radiation based methods for understanding and controlling fusion burning plasmas.

Fission and quasifission of composite systems with Z =108 -120 : Transition from heavy-ion reactions involving S and Ca to Ti and Ni ions

NASA Astrophysics Data System (ADS)

Kozulin, E. M.; Knyazheva, G. N.; Novikov, K. V.; Itkis, I. M.; Itkis, M. G.; Dmitriev, S. N.; Oganessian, Yu. Ts.; Bogachev, A. A.; Kozulina, N. I.; Harca, I.; Trzaska, W. H.; Ghosh, T. K.

2016-11-01

Background: Suppression of compound nucleus formation in the reactions with heavy ions by a quasifission process in dependence on the reaction entrance channel. Purpose: Investigation of fission and quasifission processes in the reactions 36S,48Ca,48Ti , and 64Ni+238U at energies around the Coulomb barrier. Methods: Mass-energy distributions of fissionlike fragments formed in the reaction 48Ti+238U at energies of 247, 258, and 271 MeV have been measured using the double-arm time-of-flight spectrometer CORSET at the U400 cyclotron of the Flerov Laboratory of Nuclear Reactions and compared with mass-energy distributions for the reactions 36S,48Ca,64Ni+238U . Results: The most probable fragment masses as well as total kinetic energies and their dispersions in dependence on the interaction energies have been investigated for asymmetric and symmetric fragments for the studied reactions. The fusion probabilities have been deduced from the analysis of mass-energy distributions. Conclusion: The estimated fusion probability for the reactions S, Ca, Ti, and Ni ions with actinide nuclei shows that it depends exponentially on the mean fissility parameter of the system. For the reactions with actinide nuclei leading to the formation of superheavy elements the fusion probabilities are of several orders of magnitude higher than in the case of cold fusion reactions.

Control of a laser inertial confinement fusion-fission power plant

DOEpatents

Moses, Edward I.; Latkowski, Jeffery F.; Kramer, Kevin J.

2015-10-27

A laser inertial-confinement fusion-fission energy power plant is described. The fusion-fission hybrid system uses inertial confinement fusion to produce neutrons from a fusion reaction of deuterium and tritium. The fusion neutrons drive a sub-critical blanket of fissile or fertile fuel. A coolant circulated through the fuel extracts heat from the fuel that is used to generate electricity. The inertial confinement fusion reaction can be implemented using central hot spot or fast ignition fusion, and direct or indirect drive. The fusion neutrons result in ultra-deep burn-up of the fuel in the fission blanket, thus enabling the burning of nuclear waste. Fuels include depleted uranium, natural uranium, enriched uranium, spent nuclear fuel, thorium, and weapons grade plutonium. LIFE engines can meet worldwide electricity needs in a safe and sustainable manner, while drastically shrinking the highly undesirable stockpiles of depleted uranium, spent nuclear fuel and excess weapons materials.

Dynamic approach to description of entrance channel effects in angular distributions of fission fragments

NASA Astrophysics Data System (ADS)

Eremenko, D. O.; Drozdov, V. A.; Fotina, O. V.; Platonov, S. Yu.; Yuminov, O. A.

2016-07-01

Background: It is well known that the anomalous behavior of angular anisotropies of fission fragments at sub- and near-barrier energies is associated with a memory of conditions in the entrance channel of the heavy-ion reactions, particularly, deformations and spins of colliding nuclei that determine the initial distributions for the components of the total angular momentum over the symmetry axis of the fissioning system and the beam axis. Purpose: We develop a new dynamic approach, which allows the description of the memory effects in the fission fragment angular distributions and provides new information on fusion and fission dynamics. Methods: The approach is based on the dynamic model of the fission fragment angular distributions which takes into account stochastic aspects of nuclear fission and thermal fluctuations for the tilting mode that is characterized by the projection of the total angular momentum onto the symmetry axis of the fissioning system. Another base of our approach is the quantum mechanical method to calculate the initial distributions over the components of the total angular momentum of the nuclear system immediately following complete fusion. Results: A method is suggested for calculating the initial distributions of the total angular momentum projection onto the symmetry axis for the nuclear systems formed in the reactions of complete fusion of deformed nuclei with spins. The angular distributions of fission fragments for the 16O+232Th,12C+235,236,238, and 13C+235U reactions have been analyzed within the dynamic approach over a range of sub- and above-barrier energies. The analysis allowed us to determine the relaxation time for the tilting mode and the fraction of fission events occurring in times not larger than the relaxation time for the tilting mode. Conclusions: It is shown that the memory effects play an important role in the formation of the angular distributions of fission fragments for the reactions induced by heavy ions. The approach developed for analysis of the effects is a suitable tool to get insight into the complete fusion-fission dynamics, in particular, to investigate the mechanism of the complete fusion and fission time scale.

Modification of the D2 radial wavefunction by near resonant compact states

NASA Astrophysics Data System (ADS)

Hagelstein, Peter L.

2003-03-01

We have proposed that phonon exchange can occur in the presence of a highly excited optical phonon mode during a dd-fusion reaction. We have also suggested (P. L. Hagelstein, Bull. APS 45, 235 (2000)) at new second-order site-other-site reactions can occur when the energy of a fusion reaction is transferred elsewhere. Fast particle ejecta from the experiments of Chambers( G. P. Chambers, et al, J. Fusion Energy, Vol. 9, p. 281 (1990).) and of Cecil (F. E. Cecil, et al, AIP Conf. Proc. Vol. 228, p. 383 (1990).) appear to be consistent with such a mechanism, in which a dd-fusion reaction at one site is coupled to a disintegration at another site. The dominant process of this type is the null reaction in which dd-fusion is coupled to He-4 dissociation. This process can lead to compact dd-states(P. L. Hagelstein, Bull. APS 2001), and is consistent with the Kasagi experiment(J. Kasagi et al, J. Phys. Soc. Japan 64, 777 (1995). ). We find that compact states near resonance with the molecular D2 states changes the radial wavefunction at small r.

Investigation on the quasifission process by theoretical analysis of experimental data of fissionlike reaction products

NASA Astrophysics Data System (ADS)

Giardina, G.; Nasirov, A. K.; Mandaglio, G.; Curciarello, F.; De Leo, V.; Fazio, G.; Manganaro, M.; Romaniuk, M.; Saccá, C.

2011-02-01

The hindrance to complete fusion is a phenomenon presenting in the most part of the capture events in reactions with massive nuclei. This phenomenon is due to the onset of the quasifission process which competes with complete fusion during the evolution of the composed system formed at capture stage. The branching ratio between quasifission and complete fusion strongly depends from different characteristics of reacting nuclei in the entrance channel. The experimental and theoretical investigations of reaction dynamics connected with the formation of composed system is nowadays the main subject of the nuclear reactions. There is ambiguity in establishment of the reaction mechanism leading to the observed binary fissionlike fragments. The correct estimation of the fusion probability is important in planning experiments for the synthesis of superheavy elements. The experimental determination of evaporation residues only is not enough to restore the true reaction dynamics. The experimental observation of fissionlike fragments only cannot assure the correct distinguishing of products of the quasifission, fast fission, and fusion-fission processes which have overlapping in the mass (angular, kinetic energy) distributions of fragments. In this paper we consider a wide set of reactions (with different mass asymmetry and mass symmetry parameters) with the aim to explain the role played by many quantities on the reaction mechanisms. We also present the results of study of the 48Ca+249Bk reaction used to synthesize superheavy nuclei with Z = 117 by the determination of the evaporation residue cross sections and the effective fission barriers < Bf > of excited nuclei formed along the de-excitation cascade of the compound nucleus.

Indirect Study of the 16O+16O Fusion Reaction Toward Stellar Energies by the Trojan Horse Method

NASA Astrophysics Data System (ADS)

Hayakawa, S.; Spitaleri, C.; Burtebayev, N.; Aimaganbetov, A.; Figuera, P.; Fisichella, M.; Guardo, G. L.; Igamov, S.; Indelicato, I.; Kiss, G.; Kliczewski, S.; La Cognata, M.; Lamia, L.; Lattuada, M.; Piasecki, E.; Rapisarda, G. G.; Romano, S.; Sakuta, S. B.; Siudak, R.; Trzcińska, A.; Tumino, A.; Urkinbayev, A.

2016-05-01

The 16O+16O fusion reaction is important in terms of the explosive oxygen burning process during late evolution stage of massive stars as well as understanding of the mechanism of low-energy heavy-ion fusion reactions. We aim to determine the excitation function for the most major exit channels, α+28Si and p+31P, toward stellar energies indirectly by the Trojan Horse Method via the 16O(20Ne, α28Si)α and 16O(20Ne, p31P)α three-body reactions. We report preliminary results involving reaction identification, and determination of the momentum distribution of α-16O intercluster motion in the projectile 20Ne nucleus.

Experiment and Theory for Nuclear Reactions in Nano-Materials Show e14 - e16 Solid-State Fusion Reactions

NASA Astrophysics Data System (ADS)

George, Russ

2005-03-01

Nano-lattices of deuterium loving metals exhibit coherent behavior by populations of deuterons (d's) occupying a Bloch state. Therein, coherent d-overlap occurs wherein the Bloch condition reduces the Coulomb barrier.Overlap of dd pairs provides a high probability fusion will/must occur. SEM photo evidence showing fusion events is now revealed by laboratories that load or flux d into metal nano-domains. Solid-state dd fusion creates an excited ^4He nucleus entangled in the large coherent population of d's.This contrasts with plasma dd fusion in collision space where an isolated excited ^4He nucleus seeks the ground state via fast particle emission. In momentum limited solid state fusion,fast particle emission is effectively forbidden.Photographed nano-explosive events are beyond the scope of chemistry. Corroboration of the nuclear nature derives from photographic observation of similar events on spontaneous fission, e.g. Cf. We present predictive theory, heat production, and helium isotope data showing reproducible e14 to e16 solid-state fusion reactions.

Influence of collective nonideal shielding on fusion reaction in partially ionized classical nonideal plasmas

NASA Astrophysics Data System (ADS)

Lee, Myoung-Jae; Jung, Young-Dae

2017-04-01

The collective nonideal effects on the nuclear fusion reaction process are investigated in partially ionized classical nonideal hydrogen plasmas. The effective pseudopotential model taking into account the collective and plasma shielding effects is applied to describe the interaction potential in nonideal plasmas. The analytic expressions of the Sommerfeld parameter, the fusion penetration factor, and the cross section for the nuclear fusion reaction in nonideal plasmas are obtained as functions of the nonideality parameter, Debye length, and relative kinetic energy. It is found that the Sommerfeld parameter is suppressed due to the influence of collective nonideal shielding. However, the collective nonideal shielding is found to enhance the fusion penetration factor in partially ionized classical nonideal plasmas. It is also found that the fusion penetration factors in nonideal plasmas represented by the pseudopotential model are always greater than those in ideal plasmas represented by the Debye-Hückel model. In addition, it is shown that the collective nonideal shielding effect on the fusion penetration factor decreases with an increase of the kinetic energy.

Laser-induced fast fusion of gold nanoparticle-modified polyelectrolyte microcapsules.

PubMed

Wu, Yingjie; Frueh, Johannes; Si, Tieyan; Möhwald, Helmuth; He, Qiang

2015-02-07

In this study we investigated the effect of laser-induced membrane fusion of polyelectrolyte multilayer (PEM) based microcapsules bearing surface-attached gold nanoparticles (AuNPs) in aqueous media. We demonstrate that a dense coating of the capsules with AuNPs leads to enhanced light absorption, causing an increase of local temperature. This enhances the migration of polyelectrolytes within the PEMs and thus enables a complete fusion of two or more capsules. The encapsulated substances can achieve complete merging upon short-term laser irradiation (30 s, 30 mW @ 650 nm). The whole fusion process is followed by optical microscopy and scanning electron microscopy. In control experiments, microcapsules without AuNPs do not show a significant capsule fusion upon irradiation. It was also found that the duration of capsule fusion is affected by the density of AuNPs on the shell - the higher the density of AuNPs the shorter the fusion time. All these findings confirm that laser-induced microcapsule fusion is a new type of membrane fusion. This effect helps to study the interior exchange reactions of functional microcapsules, micro-reactors and drug transport across multilayers.

Fusion Safety Program annual report, fiscal year 1994

NASA Astrophysics Data System (ADS)

Longhurst, Glen R.; Cadwallader, Lee C.; Dolan, Thomas J.; Herring, J. Stephen; McCarthy, Kathryn A.; Merrill, Brad J.; Motloch, Chester C.; Petti, David A.

1995-03-01

This report summarizes the major activities of the Fusion Safety Program in fiscal year 1994. The Idaho National Engineering Laboratory (INEL) is the designated lead laboratory and Lockheed Idaho Technologies Company is the prime contractor for this program. The Fusion Safety Program was initiated in 1979. Activities are conducted at the INEL, at other DOE laboratories, and at other institutions, including the University of Wisconsin. The technical areas covered in this report include tritium safety, beryllium safety, chemical reactions and activation product release, safety aspects of fusion magnet systems, plasma disruptions, risk assessment failure rate data base development, and thermalhydraulics code development and their application to fusion safety issues. Much of this work has been done in support of the International Thermonuclear Experimental Reactor (ITER). Also included in the report are summaries of the safety and environmental studies performed by the Fusion Safety Program for the Tokamak Physics Experiment and the Tokamak Fusion Test Reactor and of the technical support for commercial fusion facility conceptual design studies. A major activity this year has been work to develop a DOE Technical Standard for the safety of fusion test facilities.

Design Considerations for Clean QED Fusion Propulsion Systems

NASA Astrophysics Data System (ADS)

Bussard, Robert W.; Jameson, Lorin W.

1994-07-01

The direct production of electric power appears possible from fusion reactions between fuels whose products consist solely of charged particles and thus do not present radiation hazards from energetic neutron production, as do reactions involving deuteron-bearing fuels. Among these are the fuels p, 11B, 3He, and 6Li. All of these can be ``burned'' in inertial-electrostatic-fusion (IEF) devices to power QED fusion-electric rocket engines. These IEF sources provide direct-converted electrical power at high voltage (MeV) to drive e-beams for efficient propellant heating to extreme temperatures, with resulting high specific impulse performance capabilities. IEF/QED engine systems using p11B can outperform all other advanced concepts for controlled fusion propulsion by 2-3 orders of magnitude, while 6Li6Li fusion yields one order of magnitude less advance. Either of these fusion rocket propulsion systems can provide very rapid transit for solar system missions, with high payload fractions in single-stage vehicles. The 3He3He reaction can not be used practically for direct electric conversion because of the wide spread in energy of its fusion products. However, it may eventually prove useful for thermal/electrical power generation in central station power plants, or for direct-fusion-product (DFP) propellant heatingin advanced deep-space rocket engines.

Synthetic neutron camera and spectrometer in JET based on AFSI-ASCOT simulations

NASA Astrophysics Data System (ADS)

Sirén, P.; Varje, J.; Weisen, H.; Koskela, T.; contributors, JET

2017-09-01

The ASCOT Fusion Source Integrator (AFSI) has been used to calculate neutron production rates and spectra corresponding to the JET 19-channel neutron camera (KN3) and the time-of-flight spectrometer (TOFOR) as ideal diagnostics, without detector-related effects. AFSI calculates fusion product distributions in 4D, based on Monte Carlo integration from arbitrary reactant distribution functions. The distribution functions were calculated by the ASCOT Monte Carlo particle orbit following code for thermal, NBI and ICRH particle reactions. Fusion cross-sections were defined based on the Bosch-Hale model and both DD and DT reactions have been included. Neutrons generated by AFSI-ASCOT simulations have already been applied as a neutron source of the Serpent neutron transport code in ITER studies. Additionally, AFSI has been selected to be a main tool as the fusion product generator in the complete analysis calculation chain: ASCOT - AFSI - SERPENT (neutron and gamma transport Monte Carlo code) - APROS (system and power plant modelling code), which encompasses the plasma as an energy source, heat deposition in plant structures as well as cooling and balance-of-plant in DEMO applications and other reactor relevant analyses. This conference paper presents the first results and validation of the AFSI DD fusion model for different auxiliary heating scenarios (NBI, ICRH) with very different fast particle distribution functions. Both calculated quantities (production rates and spectra) have been compared with experimental data from KN3 and synthetic spectrometer data from ControlRoom code. No unexplained differences have been observed. In future work, AFSI will be extended for synthetic gamma diagnostics and additionally, AFSI will be used as part of the neutron transport calculation chain to model real diagnostics instead of ideal synthetic diagnostics for quantitative benchmarking.

Mach-Zehnder Fiber-Optic Links for ICF Diagnostics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, E. K., Hermann, H. W.

2012-11-01

This article describes the operation and evolution of Mach-Zehnder links for single-point detectors in inertial confinement fusion experimental facilities, based on the Gamma Reaction History (GRH) diagnostic at the National Ignition Facility.

A study of thermal hydraulic and kinetic phenomena in HYLIFE-2: An inertial confinement fusion reactor

NASA Astrophysics Data System (ADS)

Chen, Xiang Ming

1993-01-01

Researchers have studied the different aspects of commercial fusion energy for several decades. A variety of inertial confinement fusion (ICF) reactors have been proposed. Different from the magnetic confinement fusion concept, inertial confinement fusion does not need long-term confinement of the fusion fuel but achieves fusion reaction in a short microexplosion under a high density, high temperature condition. The HYLIFE-2 reactor design started in 1987 is based on the study of a previous concept called HYLIFE (High Yield Lithium Injection Fusion Energy). Similar to the old concept, the HYLIFE-2 design uses a vacuum chamber in which D-T fusion pellets are injected and ignited by high energy beams shot into the reactor through different ports. The reactor vessel is protected from explosion radiations by a liquid fall (blanket) that also breeds tritium through the (n, alpha) reaction of lithium and conveys the fusion energy to the power cycle. In addition to some geometric chances, the new design replaces liquid metal lithium with the molten salt Flibe (Li2BeF4) as the protective blanket material. The objective was to remove the possibility of fire hazard. The important thermal hydraulic issues in the design are (1) equation of state of Flibe; (2) liquid relaxation after isochoric (constant volume) heating; (3) ablation and gas dynamics; (4) interaction of the vapor and liquid; and (5) condensation of the vaporized material. The first four issues have to do with the internal relaxation after the fusion microexplosion in the chamber. Vaporized material, as well as liquid, may assert strong impulses on the chamber wall during the process of relaxing after absorbing the energy from the microexplosion. Item (5) is related to the rapid vacuum recovery between the ignitions. Some aspects of the first four issues are studied.

Cherenkov neutron detector for fusion reaction and runaway electron diagnostics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cheon, MunSeong, E-mail: munseong@nfri.re.kr; Kim, Junghee

2015-08-15

A Cherenkov-type neutron detector was newly developed and neutron measurement experiments were performed at Korea Superconducting Tokamak Advanced Research. It was shown that the Cherenkov neutron detector can monitor the time-resolved neutron flux from deuterium-fueled fusion plasmas. Owing to the high temporal resolution of the detector, fast behaviors of runaway electrons, such as the neutron spikes, could be observed clearly. It is expected that the Cherenkov neutron detector could be utilized to provide useful information on runaway electrons as well as fusion reaction rate in fusion plasmas.

On the implementation of a chain nuclear reaction of thermonuclear fusion on the basis of the p+11B process

NASA Astrophysics Data System (ADS)

Belyaev, V. S.; Krainov, V. P.; Zagreev, B. V.; Matafonov, A. P.

2015-07-01

Various theoretical and experimental schemes for implementing a thermonuclear reactor on the basis of the p+11B reaction are considered. They include beam collisions, fusion in degenerate plasmas, ignition upon plasma acceleration by ponderomotive forces, and the irradiation of a solid-state target from 11B with a proton beam under conditions of a Coulomb explosion of hydrogen microdrops. The possibility of employing ultra-short high-intensity laser pulses to initiate the p+11B reaction under conditions far from thermodynamic equilibrium is discussed. This and some other weakly radioactive thermonuclear reactions are promising owing to their ecological cleanness—there are virtually no neutrons among fusion products. Nuclear reactions that follow the p+11B reaction may generate high-energy protons, sustaining a chain reaction, and this is an advantage of the p+11B option. The approach used also makes it possible to study nuclear reactions under conditions close to those in the early Universe or in the interior of stars.

Helium Find Thaws the Cold Fusion Trail.

ERIC Educational Resources Information Center

Pennisi, E.

1991-01-01

Reported is a study of cold fusion in which trace amounts of helium, possible evidence of an actual fusion reaction, were found. Research methodology is detailed. The controversy over the validity of experimental results with cold fusion are reviewed. (CW)

Study of the 20,22Ne+20,22Ne and 10,12,13,14,15C+12C Fusion Reactions with MUSIC

NASA Astrophysics Data System (ADS)

Avila, M. L.; Rehm, K. E.; Almaraz-Calderon, S.; Carnelli, P. F. F.; DiGiovine, B.; Esbensen, H.; Hoffman, C. R.; Jiang, C. L.; Kay, B. P.; Lai, J.; Nusair, O.; Pardo, R. C.; Santiago-Gonzalez, D.; Talwar, R.; Ugalde, C.

2016-05-01

A highly efficient MUlti-Sampling Ionization Chamber (MUSIC) detector has been developed for measurements of fusion reactions. A study of fusion cross sections in the 10,12,13,14,15C+12C and 20,22Ne+20,22Ne systems has been performed at ATLAS. Experimental results and comparison with theoretical predictions are presented. Furthermore, results of direct measurements of the 17O(α, n)20Ne, 23Ne(α, p)26Mg and 23Ne(α, n)26Al reactions will be discussed.

Energy spectrum and kinetics of the fusing particles

NASA Astrophysics Data System (ADS)

Ryutov, D. D.; Putvinski, s. V.; Yushmanov, P. N.; TAE Team

2017-10-01

The fusing particles (e.g., D and T, or p and 11B) contribution to the reaction rate can be found by the integration of the fusion reactivity over the particle distribution functions. The distribution function (e.g., Maxwellian) is depleted in the energy range determined by the highest reactivity and has to be replenished by particle collisions. The kinetics of the replenishment process may affect the rate of fusion energy release. We present a simple analysis of the corresponding kinetic problems for the conditions typical for the standard and advanced-fuel fusion reactions and assess the possible effect on the reaction yield.

In-beam Fission Study at JAEA

NASA Astrophysics Data System (ADS)

Nishio, Katsuhisa

2013-12-01

Fission fragment mass distributions were measured in heavy-ion induced fissions using 238U target nucleus. The measured mass distributions changed drastically with incident energy. The results are explained by a change of the ratio between fusion and quasifission with nuclear orientation. A calculation based on a fluctuation dissipation model reproduced the mass distributions and their incident energy dependence. Fusion probability was determined in the analysis. Evaporation residue cross sections were calculated with a statistical model in the reactions of 30Si + 238U and 34S + 238U using the obtained fusion probability in the entrance channel. The results agree with the measured cross sections for seaborgium and hassium isotopes.

In-beam fission study for Heavy Element Synthesis

NASA Astrophysics Data System (ADS)

Nishio, Katsuhisa

2013-12-01

Fission fragment mass distributions were measured in heavy-ion induced fissions using 238U target nucleus. The measured mass distributions changed drastically with incident energy. The results are explained by a change of the ratio between fusion and qasifission with nuclear orientation. A calculation based on a fluctuation dissipation model reproduced the mass distributions and their incident energy dependence. Fusion probability was determined in the analysis. Evaporation residue cross sections were calculated with a statistical model in the reactions of 30Si + 238U and 34S + 238U using the obtained fusion probability in the entrance channel. The results agree with the measured cross sections for seaborgium and hassium isotopes.

Quark-level analogue of nuclear fusion with doubly heavy baryons.

PubMed

Karliner, Marek; Rosner, Jonathan L

2017-11-01

The essence of nuclear fusion is that energy can be released by the rearrangement of nucleons between the initial- and final-state nuclei. The recent discovery of the first doubly charmed baryon , which contains two charm quarks (c) and one up quark (u) and has a mass of about 3,621 megaelectronvolts (MeV) (the mass of the proton is 938 MeV) also revealed a large binding energy of about 130 MeV between the two charm quarks. Here we report that this strong binding enables a quark-rearrangement, exothermic reaction in which two heavy baryons (Λ c ) undergo fusion to produce the doubly charmed baryon and a neutron n (), resulting in an energy release of 12 MeV. This reaction is a quark-level analogue of the deuterium-tritium nuclear fusion reaction (DT → 4 He n). The much larger binding energy (approximately 280 MeV) between two bottom quarks (b) causes the analogous reaction with bottom quarks () to have a much larger energy release of about 138 MeV. We suggest some experimental setups in which the highly exothermic nature of the fusion of two heavy-quark baryons might manifest itself. At present, however, the very short lifetimes of the heavy bottom and charm quarks preclude any practical applications of such reactions.

Quark-level analogue of nuclear fusion with doubly heavy baryons

NASA Astrophysics Data System (ADS)

Karliner, Marek; Rosner, Jonathan L.

2017-11-01

The essence of nuclear fusion is that energy can be released by the rearrangement of nucleons between the initial- and final-state nuclei. The recent discovery of the first doubly charmed baryon , which contains two charm quarks (c) and one up quark (u) and has a mass of about 3,621 megaelectronvolts (MeV) (the mass of the proton is 938 MeV) also revealed a large binding energy of about 130 MeV between the two charm quarks. Here we report that this strong binding enables a quark-rearrangement, exothermic reaction in which two heavy baryons (Λc) undergo fusion to produce the doubly charmed baryon and a neutron n (), resulting in an energy release of 12 MeV. This reaction is a quark-level analogue of the deuterium-tritium nuclear fusion reaction (DT → 4He n). The much larger binding energy (approximately 280 MeV) between two bottom quarks (b) causes the analogous reaction with bottom quarks () to have a much larger energy release of about 138 MeV. We suggest some experimental setups in which the highly exothermic nature of the fusion of two heavy-quark baryons might manifest itself. At present, however, the very short lifetimes of the heavy bottom and charm quarks preclude any practical applications of such reactions.

Fusion peptides from oncogenic chimeric proteins as putative specific biomarkers of cancer.

PubMed

Conlon, Kevin P; Basrur, Venkatesha; Rolland, Delphine; Wolfe, Thomas; Nesvizhskii, Alexey I; MacCoss, Michael J; Lim, Megan S; Elenitoba-Johnson, Kojo S J

2013-10-01

Chromosomal translocations encoding chimeric fusion proteins constitute one of the most common mechanisms underlying oncogenic transformation in human cancer. Fusion peptides resulting from such oncogenic chimeric fusions, though unique to specific cancer subtypes, are unexplored as cancer biomarkers. Here we show, using an approach termed fusion peptide multiple reaction monitoring mass spectrometry, the direct identification of different cancer-specific fusion peptides arising from protein chimeras that are generated from the juxtaposition of heterologous genes fused by recurrent chromosomal translocations. Using fusion peptide multiple reaction monitoring mass spectrometry in a clinically relevant scenario, we demonstrate the specific, sensitive, and unambiguous detection of a specific diagnostic fusion peptide in clinical samples of anaplastic large cell lymphoma, but not in a diverse array of benign lymph nodes or other forms of primary malignant lymphomas and cancer-derived cell lines. Our studies highlight the utility of fusion peptides as cancer biomarkers and carry broad implications for the use of protein biomarkers in cancer detection and monitoring.

The cytoplasmic domain of the gamete membrane fusion protein HAP2 targets the protein to the fusion site in Chlamydomonas and regulates the fusion reaction.

PubMed

Liu, Yanjie; Pei, Jimin; Grishin, Nick; Snell, William J

2015-03-01

Cell-cell fusion between gametes is a defining step during development of eukaryotes, yet we know little about the cellular and molecular mechanisms of the gamete membrane fusion reaction. HAP2 is the sole gamete-specific protein in any system that is broadly conserved and shown by gene disruption to be essential for gamete fusion. The wide evolutionary distribution of HAP2 (also known as GCS1) indicates it was present in the last eukaryotic common ancestor and, therefore, dissecting its molecular properties should provide new insights into fundamental features of fertilization. HAP2 acts at a step after membrane adhesion, presumably directly in the merger of the lipid bilayers. Here, we use the unicellular alga Chlamydomonas to characterize contributions of key regions of HAP2 to protein location and function. We report that mutation of three strongly conserved residues in the ectodomain has no effect on targeting or fusion, although short deletions that include those residues block surface expression and fusion. Furthermore, HAP2 lacking a 237-residue segment of the cytoplasmic region is expressed at the cell surface, but fails to localize at the apical membrane patch specialized for fusion and fails to rescue fusion. Finally, we provide evidence that the ancient HAP2 contained a juxta-membrane, multi-cysteine motif in its cytoplasmic region, and that mutation of a cysteine dyad in this motif preserves protein localization, but substantially impairs HAP2 fusion activity. Thus, the ectodomain of HAP2 is essential for its surface expression, and the cytoplasmic region targets HAP2 to the site of fusion and regulates the fusion reaction. © 2015. Published by The Company of Biologists Ltd.

Study of incomplete fusion reaction dynamics in 13C +165 Ho system and its dependence on various entrance channel parameters

NASA Astrophysics Data System (ADS)

Tali, Suhail A.; Kumar, Harish; Ansari, M. Afzal; Ali, Asif; Singh, D.; Ali, Rahbar; Giri, Pankaj K.; Linda, Sneha B.; Parashari, Siddharth; Kumar, R.; Singh, R. P.; Muralithar, S.

2018-02-01

The excitation functions for the evaporation residues populated in the interaction of 13C +165 Ho system have been measured at projectile energies ≈ 4-7 MeV/nucleon. Stacked foil activation technique followed by off-line γ-ray spectroscopy have been employed in the present work. The experimentally measured cross-sections are analyzed in the frame work of statistical model code PACE4, which takes into account only the complete fusion reaction cross-sections. The evaporation residues populated via xn and pxn channels were found to be in good agreement with the PACE4 predictions, while a significant enhancement in the measured cross-sections over PACE4 predictions is observed in case of α-emitting channels, which may be attributed to the incomplete fusion process. For the better understanding of incomplete fusion dynamics, the incomplete fusion fraction has also been deduced and its sensitivity with various entrance channel parameters like: projectile energy, mass-asymmetry, projectile structure in terms of Qα-value and Coulomb effect has been studied in the present work. The incomplete fusion fraction is found to increase with increasing the projectile energy and a strong projectile structure dependent mass-asymmetry systematic is also observed. The incomplete fusion fraction is also found to be small for more negative Qα-value projectile (13C) induced reactions as compared to less negative Qα-value projectiles (12C, 16O and 20Ne) induced reactions with the same target nucleus 165Ho. An interesting trend is obtained on further investigation of incomplete fusion dependence on Coulomb effect (ZPZT).

Metal Catalyzed Fusion: Nuclear Active Environment vs. Process

NASA Astrophysics Data System (ADS)

Chubb, Talbot

2009-03-01

To achieve radiationless dd fusion and/or other LENR reactions via chemistry: some focus on environment of interior or altered near-surface volume of bulk metal; some on environment inside metal nanocrystals or on their surface; some on the interface between nanometal crystals and ionic crystals; some on a momentum shock-stimulation reaction process. Experiment says there is also a spontaneous reaction process.

Neutrinos from the primary proton-proton fusion process in the Sun

NASA Astrophysics Data System (ADS)

BOREXINO Collaboration; Bellini, G.; Benziger, J.; Bick, D.; Bonfini, G.; Bravo, D.; Caccianiga, B.; Cadonati, L.; Calaprice, F.; Caminata, A.; Cavalcante, P.; Chavarria, A.; Chepurnov, A.; D'Angelo, D.; Davini, S.; Derbin, A.; Empl, A.; Etenko, A.; Fomenko, K.; Franco, D.; Gabriele, F.; Galbiati, C.; Gazzana, S.; Ghiano, C.; Giammarchi, M.; Göger-Neff, M.; Goretti, A.; Gromov, M.; Hagner, C.; Hungerford, E.; Ianni, Aldo; Ianni, Andrea; Kobychev, V.; Korablev, D.; Korga, G.; Kryn, D.; Laubenstein, M.; Lehnert, B.; Lewke, T.; Litvinovich, E.; Lombardi, F.; Lombardi, P.; Ludhova, L.; Lukyanchenko, G.; Machulin, I.; Manecki, S.; Maneschg, W.; Marcocci, S.; Meindl, Q.; Meroni, E.; Meyer, M.; Miramonti, L.; Misiaszek, M.; Montuschi, M.; Mosteiro, P.; Muratova, V.; Oberauer, L.; Obolensky, M.; Ortica, F.; Otis, K.; Pallavicini, M.; Papp, L.; Perasso, L.; Pocar, A.; Ranucci, G.; Razeto, A.; Re, A.; Romani, A.; Rossi, N.; Saldanha, R.; Salvo, C.; Schönert, S.; Simgen, H.; Skorokhvatov, M.; Smirnov, O.; Sotnikov, A.; Sukhotin, S.; Suvorov, Y.; Tartaglia, R.; Testera, G.; Vignaud, D.; Vogelaar, R. B.; von Feilitzsch, F.; Wang, H.; Winter, J.; Wojcik, M.; Wright, A.; Wurm, M.; Zaimidoroga, O.; Zavatarelli, S.; Zuber, K.; Zuzel, G.

2014-08-01

In the core of the Sun, energy is released through sequences of nuclear reactions that convert hydrogen into helium. The primary reaction is thought to be the fusion of two protons with the emission of a low-energy neutrino. These so-called pp neutrinos constitute nearly the entirety of the solar neutrino flux, vastly outnumbering those emitted in the reactions that follow. Although solar neutrinos from secondary processes have been observed, proving the nuclear origin of the Sun's energy and contributing to the discovery of neutrino oscillations, those from proton-proton fusion have hitherto eluded direct detection. Here we report spectral observations of pp neutrinos, demonstrating that about 99 per cent of the power of the Sun, 3.84 × 1033 ergs per second, is generated by the proton-proton fusion process.

Species separation and modification of neutron diagnostics in inertial-confinement fusion

NASA Astrophysics Data System (ADS)

Inglebert, A.; Canaud, B.; Larroche, O.

2014-09-01

The different behaviours of deuterium (D) and tritium (T) in the hot spot of marginally igniting cryogenic DT inertial-confinement fusion (ICF) targets are investigated with an ion Fokker-Planck model. With respect to an equivalent single-species model, a higher density and a higher temperature are found for T in the stagnation phase of the target implosion. In addition, the stagnating hot spot is found to be less dense but hotter than in the single-species case. As a result, the fusion reaction yield in the hot spot is significantly increased. Fusion neutron diagnostics of the implosion find a larger ion temperature as deduced from DT reactions than from DD reactions, in good agreement with NIF experimental results. ICF target designs should thus definitely take ion-kinetic effects into account.

Radioactivity measurements of ITER materials using the TFTR D-T neutron field

NASA Astrophysics Data System (ADS)

Kumar, A.; Abdou, M. A.; Barnes, C. W.; Kugel, H. W.

1994-06-01

The availability of high D-T fusion neutron yields at TFTR has provided a useful opportunity to directly measure D-T neutron-induced radioactivity in a realistic tokamak fusion reactor environment for materials of vital interest to ITER. These measurements are valuable for characterizing radioactivity in various ITER candidate materials, for validating complex neutron transport calculations, and for meeting fusion reactor licensing requirements. The radioactivity measurements at TFTR involve potential ITER materials including stainless steel 316, vanadium, titanium, chromium, silicon, iron, cobalt, nickel, molybdenum, aluminum, copper, zinc, zirconium, niobium, and tungsten. Small samples of these materials were irradiated close to the plasma and just outside the vacuum vessel wall of TFTR, locations of different neutron energy spectra. Saturation activities for both threshold and capture reactions were measured. Data from dosimetric reactions have been used to obtain preliminary neutron energy spectra. Spectra from the first wall were compared to calculations from ITER and to measurements from accelerator-based tests.

Thermonuclear reactions probed at stellar-core conditions with laser-based inertial-confinement fusion

DOE PAGES

Casey, D. T.; Sayre, D. B.; Brune, C. R.; ...

2017-08-07

Stars are giant thermonuclear plasma furnaces that slowly fuse the lighter elements in the universe into heavier elements, releasing energy, and generating the pressure required to prevent collapse. To understand stars, we must rely on nuclear reaction rate data obtained, up to now, under conditions very different from those of stellar cores. Here we show thermonuclear measurements of the 2H(d, n) 3He and 3H(t,2n) 4He S-factors at a range of densities (1.2–16 g cm –3) and temperatures (2.1–5.4 keV) that allow us to test the conditions of the hydrogen-burning phase of main-sequence stars. The relevant conditions are created using inertial-confinementmore » fusion implosions at the National Ignition Facility. Here, our data agree within uncertainty with previous accelerator-based measurements and establish this approach for future experiments to measure other reactions and to test plasma-nuclear effects present in stellar interiors, such as plasma electron screening, directly in the environments where they occur.« less

Study on ( n,t) Reactions of Zr, Nb and Ta Nuclei

NASA Astrophysics Data System (ADS)

Tel, E.; Yiğit, M.; Tanır, G.

2012-04-01

The world faces serious energy shortages in the near future. To meet the world energy demand, the nuclear fusion with safety, environmentally acceptability and economic is the best suited. Fusion is attractive as an energy source because of the virtually inexhaustible supply of fuel, the promise of minimal adverse environmental impact, and its inherent safety. Fusion will not produce CO2 or SO2 and thus will not contribute to global warming or acid rain. Furthermore, there are not radioactive nuclear waste problems in the fusion reactors. Although there have been significant research and development studies on the inertial and magnetic fusion reactor technology, there is still a long way to go to penetrate commercial fusion reactors to the energy market. Because, tritium self-sufficiency must be maintained for a commercial power plant. For self-sustaining (D-T) fusion driver tritium breeding ratio should be greater than 1.05. And also, the success of fusion power system is dependent on performance of the first wall, blanket or divertor systems. So, the performance of structural materials for fusion power systems, understanding nuclear properties systematic and working out of ( n,t) reaction cross sections are very important. Zirconium (Zr), Niobium (Nb) and Tantal (Ta) containing alloys are important structural materials for fusion reactors, accelerator-driven systems, and many other fields. In this study, ( n,t) reactions for some structural fusion materials such as 88,90,92,94,96Zr, 93,94,95Nb and 179,181Ta have been investigated. The calculated results are discussed andcompared with the experimental data taken from the literature.

Calculations of Excitation Functions of Some Structural Fusion Materials for ( n, t) Reactions up to 50 MeV Energy

NASA Astrophysics Data System (ADS)

Tel, E.; Durgu, C.; Aktı, N. N.; Okuducu, Ş.

2010-06-01

Fusion serves an inexhaustible energy for humankind. Although there have been significant research and development studies on the inertial and magnetic fusion reactor technology, there is still a long way to go to penetrate commercial fusion reactors to the energy market. Tritium self-sufficiency must be maintained for a commercial power plant. For self-sustaining (D-T) fusion driver tritium breeding ratio should be greater than 1.05. So, the working out the systematics of ( n, t) reaction cross sections is of great importance for the definition of the excitation function character for the given reaction taking place on various nuclei at different energies. In this study, ( n, t) reactions for some structural fusion materials such as 27Al, 51V, 52Cr, 55Mn, and 56Fe have been investigated. The new calculations on the excitation functions of 27Al( n, t)25Mg, 51V( n, t)49Ti, 52Cr( n, t)50V, 55Mn( n, t)53Cr and 56Fe( n, t)54Mn reactions have been carried out up to 50 MeV incident neutron energy. In these calculations, the pre-equilibrium and equilibrium effects have been investigated. The pre-equilibrium calculations involve the new evaluated the geometry dependent hybrid model, hybrid model and the cascade exciton model. Equilibrium effects are calculated according to the Weisskopf-Ewing model. Also in the present work, we have calculated ( n, t) reaction cross-sections by using new evaluated semi-empirical formulas developed by Tel et al. at 14-15 MeV energy. The calculated results are discussed and compared with the experimental data taken from the literature.

/sup 18/O + /sup 12/C fusion-evaporation reaction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Heusch, B; Beck, C; Coffin, J P

1980-01-01

A study of the /sup 18/O + /sup 12/C fusion evaporation reaction has been undertaken for 2 reasons: to make a systematic study of the formation cross section for each individual evaporation residue over a broad excitation energy region in the compound nucleus /sup 30/Si:30 to 62 MeV; and to compare all results to fusion-evaporation calculations done in the framework of the Hauser-Feschbach statistical model.

Role of partial linear momentum transfer on incomplete fusion reaction

NASA Astrophysics Data System (ADS)

Ali, Sabir; Ahmad, Tauseef; Kumar, Kamal; Gull, Muntazir; Rizvi, I. A.; Agarwal, Avinash; Ghugre, S. S.; Sinha, A. K.; Chaubey, A. K.

2018-04-01

Measurements of forward recoil range distributions (FRRDs) of the evaporation residues, populated in the 20Ne+51V reaction at E_{lab}≈ 145 MeV, have been carried out using the offline characteristic γ-ray detection method. The observation does corroborate the presence of complete fusion (CF) process in the population of p xn channel residues and both complete as well as incomplete fusion (ICF) processes in the population of α emitting channel residues. The FRRDs of p xn channel residues comprise single peak only, whereas α emitting channel residues have multiple peaks in their FRRDs. CF cross section data were used to extract the fusion functions. Extracted fusion functions were found to be suppressed with respect to the universal fusion function which is used as a uniform standard reference. The observed contribution arising from the ICF process in the population of α emitting channel residues is explained in terms of breakup fusion model.

Fusion Power measurement at ITER

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bertalot, L.; Barnsley, R.; Krasilnikov, V.

2015-07-01

Nuclear fusion research aims to provide energy for the future in a sustainable way and the ITER project scope is to demonstrate the feasibility of nuclear fusion energy. ITER is a nuclear experimental reactor based on a large scale fusion plasma (tokamak type) device generating Deuterium - Tritium (DT) fusion reactions with emission of 14 MeV neutrons producing up to 700 MW fusion power. The measurement of fusion power, i.e. total neutron emissivity, will play an important role for achieving ITER goals, in particular the fusion gain factor Q related to the reactor performance. Particular attention is given also tomore » the development of the neutron calibration strategy whose main scope is to achieve the required accuracy of 10% for the measurement of fusion power. Neutron Flux Monitors located in diagnostic ports and inside the vacuum vessel will measure ITER total neutron emissivity, expected to range from 1014 n/s in Deuterium - Deuterium (DD) plasmas up to almost 10{sup 21} n/s in DT plasmas. The neutron detection systems as well all other ITER diagnostics have to withstand high nuclear radiation and electromagnetic fields as well ultrahigh vacuum and thermal loads. (authors)« less

Anomalous anisotropies of fission fragments in near- and sub-barrier fusion-fussion reactions

NASA Astrophysics Data System (ADS)

Huanqiao, Zhang; Zuhua, Liu; Jincheng, Xu; Jun, Lu; Ming, Ruan; Kan, Xu

1992-03-01

Fission cross sections and angular distributions have been measured for the reactions of 16O + 232Th and238U, and19F + 208Pb and232Th at near- and sub-barrier energies. The fission excitation functions are rather well reproduced on the basis of Wong model or coupled channels theory. However, the models which reproduce the sub-barrier fusion cross sections fail to account for the experimental anisotropies of fission fragments. It is found that the observed anisotropies are much larger than expected. For the first time it has been observed that the anisotropies as a function of the center-of-mass energy show a peak centered near 4.5 MeV below the fusion barrier for several reaction systems. The present approaches fail to explain these anomalies. For 19F + 208Pb systems, our results confirm the prediction of an approximately constant value for the mean square spin of the compound nucleus produced in far sub-barrier fusion reaction.

Selection of different reaction channels in 6Li induced fusion reaction by a powerful combination of a charged particle array and a high-resolution gamma spectrometer

NASA Astrophysics Data System (ADS)

Zhang, G. X.; Hu, S. P.; Zhang, G. L.; Zhang, H. Q.; Yao, Y. J.; Huang, Z.; Wang, M. L.; Sun, H. B.; Valiente-Dobòn, J. J.; Testov, D.; Goasduff, A.; John, P. R.; Siciliano, M.; Galtarosa, F.; Francesco, R.; Mengoni, D.; Bazzacco, D.; Li, E. T.; Hao, X.

2018-05-01

Investigation of the breakup and transfer effect of weakly bound nuclei on the fusion process has been an interesting research topic in the past several years. In comparison with radioactive ion beam (RIB), the beam intensities of stable weakly bound nuclei such as 6,7Li and 9Be, which have significant breakup probability, are orders of magnitude higher. Precise fusion measurements induced by these nuclei have already been performed. However, the conclusion of reaction dynamics was not clear and has contradiction. In order to have a proper understanding of the influence of breakup and transfer of weakly bound projectiles on the fusion process, the 6Li+89Y experiment with incident energies of 22 MeV and 34 MeV was performed on Galileo array in combination with Si-ball EUCLIDES at Legnaro National Laboratory (LNL) in Italy. Using the coincidence by the charged particles and γ-rays, the different reaction channels can be clearly identified.

Nuclear fusion driven by Coulomb explosion of homonuclear and heteronuclear deuterium- and tritium-containing clusters

NASA Astrophysics Data System (ADS)

Last, Isidore; Jortner, Joshua

2001-12-01

The ionization and Coulomb explosion of homonuclear Dn and Tn (n=959-8007) and heteronuclear (D2O)n and (T2O)n (n=459-2171) clusters in very intense (I=5×1014-5×1018 W cm-2) laser fields is studied using classical dynamics simulations. The efficiency of the d+d and d+t nuclear fusion driven by the Coulomb explosion (NFDCE) is explored. The d+d NFDCE of (D2O)n heteronuclear clusters is enhanced by energetic and kinematic effects for D+, while for (T2O)n heteronuclear clusters the kinetic energy of T+ is dominated by energetic effects. The cluster size dependence of the fusion reaction yield has been established. The heteronuclear clusters provide considerably higher d+d and d+t fusion reaction yields than the homonuclear clusters of the same size. The clusters consisting of both D and T atoms can provide highly efficient d+t fusion reactions.

Theoretical Study of the Effects of Di-Muonic Molecules on Muon-Catalyzed Fusion

DTIC Science & Technology

2012-03-01

For example, synthetic zeolites could be used to separate molecular isotopes of hydrogen [12; 10] as could thermal diffusion and gas chromatography... thermal muon flux is large (see Chapter 8). Reactions which have the potential of increasing the muon-catalyzed fusion rate and reactions that could...the remainder of this document. Changes to the muon-catalyzed fusion cycle, that are expected to occur when the thermal muon flux is high, are

On the implementation of a chain nuclear reaction of thermonuclear fusion on the basis of the p+{sup 11}B process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Belyaev, V. S.; Krainov, V. P., E-mail: vpkrainov@mail.ru; Zagreev, B. V.

2015-07-15

Various theoretical and experimental schemes for implementing a thermonuclear reactor on the basis of the p+{sup 11}B reaction are considered. They include beam collisions, fusion in degenerate plasmas, ignition upon plasma acceleration by ponderomotive forces, and the irradiation of a solid-state target from {sup 11}B with a proton beam under conditions of a Coulomb explosion of hydrogen microdrops. The possibility of employing ultra-short high-intensity laser pulses to initiate the p+{sup 11}B reaction under conditions far from thermodynamic equilibrium is discussed. This and some other weakly radioactive thermonuclear reactions are promising owing to their ecological cleanness—there are virtually no neutrons amongmore » fusion products. Nuclear reactions that follow the p+{sup 11}B reaction may generate high-energy protons, sustaining a chain reaction, and this is an advantage of the p+{sup 11}B option. The approach used also makes it possible to study nuclear reactions under conditions close to those in the early Universe or in the interior of stars.« less

Effect of projectile on incomplete fusion reactions at low energies

NASA Astrophysics Data System (ADS)

Sharma, Vijay R.; Shuaib, Mohd.; Yadav, Abhishek; Singh, Pushpendra P.; Sharma, Manoj K.; Kumar, R.; Singh, Devendra P.; Singh, B. P.; Muralithar, S.; Singh, R. P.; Bhowmik, R. K.; Prasad, R.

2017-11-01

Present work deals with the experimental studies of incomplete fusion reaction dynamics at energies as low as ≈ 4 - 7 MeV/A. Excitation functions populated via complete fusion and/or incomplete fusion processes in 12C+175Lu, and 13C+169Tm systems have been measured within the framework of PACE4 code. Data of excitation function measurements on comparison with different projectile-target combinations suggest the existence of ICF even at slightly above barrier energies where complete fusion (CF) is supposed to be the sole contributor, and further demonstrates strong projectile structure dependence of ICF. The incomplete fusion strength functions for 12C+175Lu, and 13C+169Tm systems are analyzed as a function of various physical parameters at a constant vrel ≈ 0.053c. It has been found that one neutron (1n) excess projectile 13C (as compared to 12C) results in less incomplete fusion contribution due to its relatively large negative α-Q-value, hence, α Q-value seems to be a reliable parameter to understand the ICF dynamics at low energies. In order to explore the reaction modes on the basis of their entry state spin population, the spin distribution of residues populated via CF and/or ICF in 16O+159Tb system has been done using particle-γ coincidence technique. CF-α and ICF-α channels have been identified from backward (B) and forward (F) α-gated γspectra, respectively. Reaction dependent decay patterns have been observed in different α emitting channels. The CF channels are found to be fed over a broad spin range, however, ICF-α channels was observed only for high-spin states. Further, the existence of incomplete fusion at low bombarding energies indicates the possibility to populate high spin states

Neutron counter based on beryllium activation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bienkowska, B.; Prokopowicz, R.; Kaczmarczyk, J.

2014-08-21

The fusion reaction occurring in DD plasma is followed by emission of 2.45 MeV neutrons, which carry out information about fusion reaction rate and plasma parameters and properties as well. Neutron activation of beryllium has been chosen for detection of DD fusion neutrons. The cross-section for reaction {sup 9}Be(n, α){sup 6}He has a useful threshold near 1 MeV, which means that undesirable multiple-scattered neutrons do not undergo that reaction and therefore are not recorded. The product of the reaction, {sup 6}He, decays with half-life T{sub 1/2} = 0.807 s emitting β{sup −} particles which are easy to detect. Large areamore » gas sealed proportional detector has been chosen as a counter of β–particles leaving activated beryllium plate. The plate with optimized dimensions adjoins the proportional counter entrance window. Such set-up is also equipped with appropriate electronic components and forms beryllium neutron activation counter. The neutron flux density on beryllium plate can be determined from the number of counts. The proper calibration procedure needs to be performed, therefore, to establish such relation. The measurements with the use of known β–source have been done. In order to determine the detector response function such experiment have been modeled by means of MCNP5–the Monte Carlo transport code. It allowed proper application of the results of transport calculations of β{sup −} particles emitted from radioactive {sup 6}He and reaching proportional detector active volume. In order to test the counter system and measuring procedure a number of experiments have been performed on PF devices. The experimental conditions have been simulated by means of MCNP5. The correctness of simulation outcome have been proved by measurements with known radioactive neutron source. The results of the DD fusion neutron measurements have been compared with other neutron diagnostics.« less

Influence of incomplete fusion on complete fusion at energies above the Coulomb barrier

NASA Astrophysics Data System (ADS)

Shuaib, Mohd; Sharma, Vijay R.; Yadav, Abhishek; Sharma, Manoj Kumar; Singh, Pushpendra P.; Singh, Devendra P.; Kumar, R.; Singh, R. P.; Muralithar, S.; Singh, B. P.; Prasad, R.

2017-10-01

In the present work, excitation functions of several reaction residues in the system 19F+169Tm, populated via the complete and incomplete fusion processes, have been measured using off-line γ-ray spectroscopy. The analysis of excitation functions has been done within the framework of statistical model code pace4. The excitation functions of residues populated via xn and pxn channels are found to be in good agreement with those estimated by the theoretical model code, which confirms the production of these residues solely via complete fusion process. However, a significant enhancement has been observed in the cross-sections of residues involving α-emitting channels as compared to the theoretical predictions. The observed enhancement in the cross-sections has been attributed to the incomplete fusion processes. In order to have a better insight into the onset and strength of incomplete fusion, the incomplete fusion strength function has been deduced. At present, there is no theoretical model available which can satisfactorily explain the incomplete fusion reaction data at energies ≈4-6 MeV/nucleon. In the present work, the influence of incomplete fusion on complete fusion in the 19F+169Tm system has also been studied. The measured cross-section data may be important for the development of reactor technology as well. It has been found that the incomplete fusion strength function strongly depends on the α-Q value of the projectile, which is found to be in good agreement with the existing literature data. The analysis strongly supports the projectile-dependent mass-asymmetry systematics. In order to study the influence of Coulomb effect ({Z}{{P}}{Z}{{T}}) on incomplete fusion, the deduced strength function for the present work is compared with the nearby projectile-target combinations. The incomplete fusion strength function is found to increase linearly with {Z}{{P}}{Z}{{T}}, indicating a strong influence of Coulomb effect in the incomplete fusion reactions.

Role of wave packet width in quantum molecular dynamics in fusion reactions near barrier

NASA Astrophysics Data System (ADS)

Cao, X. G.; Ma, Y. G.; Zhang, G. Q.; Wang, H. W.; Anastasi, A.; Curciarello, F.; De Leo, V.

2014-05-01

The dynamical fusion process of 48Ca + 144Sm with different impact parameters near barrier is studied by an extended quantum molecular dynamics (EQMD) model, where width of wavepacket is dynamically treated based on variational principle. The time evolution of different energy components such as potential energy, kinetic energy, Coulomb energy and Pauli potential are analyzed when dynamical or fixed width is assumed in calculation. It is found that the dynamical wavepacket width can enhance the dissipation of incident energy and the fluctuations, which are important to form compound nuclei. Moreover, we compare the fusion barrier dependence on the incident energy when it is determined by both dynamical and fixed wavepacket width.

Coupled-channel calculation for cross section of fusion and barrier distribution of {}^{16,17,18}O + {}^{16}O reactions

NASA Astrophysics Data System (ADS)

Fereidonnejad, R.; Sadeghi, H.; Ghambari, M.

2018-03-01

In this work, the effect of multi-phonon excitation on heavy-ion fusion reactions has been studied and fusion barrier distributions of energy intervals near and below the Coulomb barrier have been studied for 16,17,18O + 16O reactions. The structure and deformation of nuclear projectiles have been studied. Given the adaptation of computations to experimental data, our calculations predict the behavior of reactions in intervals of energy in which experimental measurements are not available. In addition the S-factor for these reactions has been calculated. The results showed that the structure and deformation of a nuclear projectile are important factors. The S-factor, obtained in the coupled-channel calculations for the {}^{16}O + {}^{16}O, {}^{17}O +{}^{16}O and {}^{18}O +{}^{16}O reactions, showed good agreement with the experimental data and had a maximum value at an energy near 5, 4.5 and 4 MeV, respectively.

Quantum shielding effects on the Gamow penetration factor for nuclear fusion reaction in quantum plasmas

NASA Astrophysics Data System (ADS)

Lee, Myoung-Jae; Jung, Young-Dae

2017-01-01

The quantum shielding effects on the nuclear fusion reaction process are investigated in quantum plasmas. The closed expression of the classical turning point for the Gamow penetration factor in quantum plasmas is obtained by the Lambert W-function. The closed expressions of the Gamow penetration factor and the cross section for the nuclear fusion reaction in quantum plasmas are obtained as functions of the plasmon energy and the relative kinetic energy by using the effective interaction potential with the WKB analysis. It is shown that the influence of quantum screening suppresses the Sommerfeld reaction factor. It is also shown that the Gamow penetration factor increases with an increase of the plasmon energy. It is also shown that the quantum shielding effect enhances the deuterium formation by the proton-proton reaction in quantum plasmas. In addition, it is found that the energy dependences on the reaction cross section and the Gamow penetration factor are more significant in high plasmon-energy domains.

Conventional Physics can Explain Excess Heat in the Fleischmann-Pons Cold Fusion Effect

NASA Astrophysics Data System (ADS)

Chubb, Scott

2011-03-01

In 1989, when Fleischmann and Pons (FP) claimed they had created room temperature, nuclear fusion in a solid, a firestorm of controversy erupted. Beginning in 1991, the Office of Naval Research began a decade-long study of the FP excess heat effect. This effort documented the fact that the excess heat that FP observed is the result of a form of nuclear fusion that can occur in solids at reduced temperature, dynamically, through a deuteron (d)+d?helium-4 reaction, without high-energy particles or ? rays. This fact has been confirmed at SRI and at a number of other laboratories (most notably in the laboratory of Y. Arata, located at Osaka University, Japan). A key reason this fact has not been accepted is the lack of a cogent argument, based on fundamental physical ideas, justifying it. In the paper, this question is re-examined, based on a generalization of conventional energy band theory that applies to finite, periodic solids, in which d's are allowed to occupy wave-like, ion band states, similar to the kinds of states that electrons occupy in ordinary metals. Prior to being experimentally observed, the Ion Band State Theory of cold fusion predicted a potential d+d?helium-4 reaction, without high energy particles, would explain the excess heat, the helium-4 would be found in an unexpected place (outside heat- producing electrodes), and high-loading, x?1, in PdDx, would be required.

Block Ignition Inertial Confinement Fusion (ICF) with Condensed Matter Cluster Type Targets for p-B11 Powered Space Propulsion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miley, George H.; Hora, H.; Badziak, J.

The use of laser-driven Inertial Confinement Fusion (ICF) for space propulsion has been the subject of several earlier conceptual design studies, (see: Orth, 1998; and other references therein). However, these studies were based on older ICF technology using either 'direct' or 'in-direct x-ray driven' type target irradiation. Important new directions have opened for laser ICF in recent years following the development of 'chirped' lasers capable of ultra short pulses with powers of TW up to few PW which leads to the concept of 'fast ignition (FI)' to achieve higher energy gains from target implosions. In a recent publication the authorsmore » showed that use of a modified type of FI, termed 'block ignition' (Miley et al., 2008), could meet many of the requirements anticipated (but not then available) by the designs of the Vehicle for Interplanetary Space Transport Applications (VISTA) ICF fusion propulsion ship (Orth, 2008) for deep space missions. Subsequently the first author devised and presented concepts for imbedding high density condensed matter 'clusters' of deuterium into the target to obtain ultra high local fusion reaction rates (Miley, 2008). Such rates are possible due to the high density of the clusters (over an order of magnitude above cryogenic deuterium). Once compressed by the implosion, the yet higher density gives an ultra high reaction rate over the cluster volume since the fusion rate is proportional to the square of the fuel density. Most recently, a new discovery discussed here indicates that the target matrix could be composed of B{sup 11} with proton clusters imbedded. This then makes p-B{sup 11} fusion practical, assuming all of the physics issues such as stability of the clusters during compression are resolved. Indeed, p-B{sup 11} power is ideal for fusion propulsion since it has a minimum of unwanted side products while giving most of the reaction energy to energetic alpha particles which can be directed into an exhaust (propulsion) nozzle. Power plants using p-B{sup 11} have been discussed for such applications before, but prior designs face formidable physics/technology issues, largely overcome with the present approach.« less

Extended fusion yield integral using pathway idea in case of Shock-compressed heated plasma

NASA Astrophysics Data System (ADS)

Kumar, Dilip; Haubold, Hans

The extended non-resonant thermonuclear reaction rate probability integral obtained in Haubold and Kumar [Haubold, H.J. and Kumar, D.: 2008, Extension of thermonuclear functions through the pathway model including Maxwell-Boltzmann and Tsallis distributions, Astroparticle Physics, 29, 70-76] is used to evaluate the fusion energy by itegrating it over temperature. The closed form representation of the extended reaction rate integral via Meijer's G-function is expressed as a solution of a homogeneous differential equation. A physical model of Guderley[Guderley G. :1942, Starke kugelige und zylindrische Verdichtungsstsse in der Nhe des Kugelmittelpunktes bzw. der Zylinderachse, Luftfahrtforschung, 19, 302] has been considered for the laser driven hydrodynamical process in a compressed fusion plasma and heated strong spherical shock wave. The fusion yield integral obtained in the paper is compared with the standard fusion yield ob-tained by Haubold and John [Haubold, H.J. and John, R.W.:1981, Analytical representation of the thermonuclear reaction rate and fusion energy production in a spherical plasma shock wave, Plasma Physics, 5, 399-411]. The pathway parameter used in this paper is given an interpretation in terms of moments.

The fusion of advanced fuels to produce medical isotopes using inertial electrostatic confinement

NASA Astrophysics Data System (ADS)

Cipiti, Benjamin B.

Experiments are described that used an Inertial Electrostatic Confinement (IEC) fusion device to create radioisotopes for medical diagnostics. The IEC concept utilizes spherically concentric electrodes to accelerate fusion ions to high energies, allowing the use of the D-D and advanced D-3He fusion reactions. The D-3He reaction produces a high-energy 14.7 MeV proton, and this proton is energetic enough to be used to create radioisotopes. This dissertation focuses first on where specifically the fusion reactions are occurring in the IEC device. It was found that at 2 mtorr operating pressures, 70% of the D-D reactions occur throughout the entire volume of the vacuum chamber. About 22% of the reactions occur in a small core in the center of the device, and the other 8% are due to embedded D-D reactions in the cathode of the device. On the other hand, for D-3He, 95% of the reactions are due to embedded reactions, and the other 5% come from a small core in the center of the device. Beam-target D-3He fusion was used to create medical isotopes in two different systems. The designs focused on creating short-lived species capable of use in Positron Emission Tomography. The first isotope created was 94mTc, a positron emitter with a 52-minute half-life. Approximately 1.5 nCi of 94mTc were created using the 94Mo(p,n) 94mTc reaction. The second isotope created was 13N, a positron emitter with a ten-minute half-life. Approximately 1.0 nCi of 13N was created using the 16O(p,alpha)13N reaction. The final part of the research investigated the effects of deuterium and helium implantation in the tungsten-rhenium cathode of the IEC device. The effect of the implantation on the surface morphology of pure tungsten was also determined using scanning electron microscopy. Deuterium did not appear to affect the surface of tungsten after high temperature (>800 C) implantation. Helium created a porous surface structure at the same temperatures starting at about 4 x 1016 ions/cm2. The pores increased in size and decreased in density with increasing temperature and fluence.

Ion acceleration and D-D nuclear fusion in laser-generated plasma from advanced deuterated polyethylene.

PubMed

Torrisi, Lorenzo

2014-10-23

Deuterated polyethylene targets have been irradiated by means of a 1016 W/cm2 laser using 600 J pulse energy, 1315 nm wavelength, 300 ps pulse duration and 70 micron spot diameter. The plasma parameters were measured using on-line diagnostics based on ion collectors, SiC detectors and plastic scintillators, all employed in time-of-flight configuration. In addition, a Thomson parabola spectrometer, an X-ray streak camera, and calibrated neutron dosimeter bubble detectors were employed. Characteristic protons and neutrons at maximum energies of 3.0 MeV and 2.45 MeV, respectively, were detected, confirming that energy spectra of reaction products coming from deuterium-deuterium nuclear fusion occur. In thick advanced targets a fusion rate of the order of 2 × 108 fusions per laser shot was calculated.

Experimental Investigation of Ternary Alloys for Fusion Breeding Blankets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Choi, B. William; Chiu, Ing L.

Future fusion power plants based on the deuterium-tritium (DT) fuel cycle will be required to breed the T fuel via neutron reactions with lithium, which will be incorporated in a breeding blanket that surrounds the fusion source. Recent work by LLNL proposed the used of liquid Li as the breeder in an inertial fusion energy (IFE) power plant. Subsequently, an LDRD was initiated to develop alternatives ternary alloy liquid metal breeders that have reduced chemical reactivity with water and air compared to pure Li. Part of the work plan was to experimentally investigate the phase diagrams of ternary alloys. Ofmore » particular interest was measurement of the melt temperature, which must be low enough to be compatible with the temperature limits of the steel used in the construction of the chamber and heat transfer system.« less

Measurements of fusion neutron yields by neutron activation technique: Uncertainty due to the uncertainty on activation cross-sections

NASA Astrophysics Data System (ADS)

Stankunas, Gediminas; Batistoni, Paola; Sjöstrand, Henrik; Conroy, Sean; JET Contributors

2015-07-01

The neutron activation technique is routinely used in fusion experiments to measure the neutron yields. This paper investigates the uncertainty on these measurements as due to the uncertainties on dosimetry and activation reactions. For this purpose, activation cross-sections were taken from the International Reactor Dosimetry and Fusion File (IRDFF-v1.05) in 640 groups ENDF-6 format for several reactions of interest for both 2.5 and 14 MeV neutrons. Activation coefficients (reaction rates) have been calculated using the neutron flux spectra at JET vacuum vessel, both for DD and DT plasmas, calculated by MCNP in the required 640-energy group format. The related uncertainties for the JET neutron spectra are evaluated as well using the covariance data available in the library. These uncertainties are in general small, but not negligible when high accuracy is required in the determination of the fusion neutron yields.

The Study of ( n, d) Reaction Cross Sections for New Evaluated Semi-Empirical Formula Using Optical Model

NASA Astrophysics Data System (ADS)

Bölükdemir, M. H.; Tel, E.; Okuducu, Ş.; Aydın, A.

2009-12-01

Nuclear fusion can be one of the most attractive sources of energy from the viewpoint of safety and minimal environmental impact. The neutron scattering cross sections data have a critical importance on fusion reactor (and in the fusion-fission hybrid) reactors. So, the study of the systematic of ( n, d) etc., reaction cross sections is of great importance in the definition of the excitation function character for reaction taking place on various nuclei at energies up to 20 MeV. In this study, non-elastic cross-sections have been calculated by using optical model for ( n, d) reactions at 14-15 MeV energy. The excitation function character and reaction Q-values depending on the asymmetry term effect for the ( n, d) reaction have been investigated. New coefficients have been obtained and the semi-empirical formulas including optical model non-elastic effects by fitting two parameters for the ( n, d) reaction cross-sections have been suggested. The obtained cross-section formulas with new coefficients have been compared with the available experimental data and discussed.

LUNA, an underground nuclear astrophysics laboratory: recent results and future perspectives

NASA Astrophysics Data System (ADS)

Corvisiero, P.

2005-05-01

It is known that the chemical elements and their isotopes were created by nuclear fusion reactions in the hot interiors of remote and long-vanished stars over many billions of years. The present picture is that all elements from carbon to uranium have been produced entirely within stars during their fiery lifetimes and explosive deaths. The detailed understanding of the origin of the chemical elements and their isotopes combines astrophysics and nuclear physics, and forms what is called nuclear astrophysics. In turn, nuclear reactions are at the heart of nuclear astrophysics: they influence sensitively the nucleosynthesis of the elements in the earliest stages of the universe and in all the objects formed thereafter, and control the associated energy generation, neutrino luminosity, and evolution of stars. A good knowledge of the rates of these fusion reactions is essential to understanding this broad picture. Some of the most important experimental techniques to measure the corresponding cross sections, based both on direct and indirect methods, will be described in this paper.

Using Secondary Nuclear Reaction Products to Infer the Fuel Areal Density, Convergence, and Electron Temperatures of Imploding D2 and D3 He Filled Capsules on the NIF

NASA Astrophysics Data System (ADS)

Lahmann, B.; Frenje, J. A.; Gatu Johnson, M.; Seguin, F. H.; Li, C. K.; Petrasso, R. D.; Hartouni, E. P.; Yeamans, C. B.; Rinderknecht, H. G.; Sayre, D. B.; Grim, G.; Baker, K.; Casey, D. T.; Dewald, E.; Goyon, C.; Jarrott, L. C.; Khan, S.; Lepape, S.; Ma, T.; Pickworth, L.; Shah, R.; Kline, J. L.; Perry, T.; Zylstra, A.; Yi, S. A.

2017-10-01

In deuterium-filled inertial confinement fusion implosions, 0.82 MeV 3He and 1.01 MeV T (generated by the primary DD reaction branches) can undergo fusion reactions with the thermal deuterium plasma to create secondary D3He protons and DT neutrons, respectively. In regimes of moderate fuel areal density (ρR 5 - 100 mg/cm2) the ratio of both of these secondary yields to the primary yield can be used to infer the fuel ρR, convergence ratio (CR), and an electron temperature (Te) . This technique has been used on a myriad of deuterium filled capsule implosion experiments on the NIF using the neutron time of flight (nTOF) diagnostics to measure the yield of secondary DT neutrons and CR-39 based wedge range filters (WRFs) to measure the yield of secondary D3He protons. This work is supported in part by the U.S. DoE and LLNL.

On the enhancement of p-11B fusion reaction rate in laser-driven plasma by α → p collisional energy transfer

NASA Astrophysics Data System (ADS)

Belloni, Fabio; Margarone, Daniele; Picciotto, Antonino; Schillaci, Francesco; Giuffrida, Lorenzo

2018-02-01

The possibility of triggering an avalanche reaction in laser-driven p-11B fusion by the effect of collisional energy transfer from α particles to protons has recently been debated, especially in connection to the high yield of α particles (4 × 108 per laser shot) achieved on engineered targets at the Prague Asterix Laser System (PALS), with a pulse of 500 J, 0.3 ns FWHM. We elucidate this controversial subject within the framework of a simple two-population model for protons, based on the binary collision theory in a plasma. We find an avalanche characteristic time of almost 1 μs for the 675 keV fusion cross section resonance in typical PALS plasma, upon idealized confinement conditions. This avalanche time is one order of magnitude higher than previously reported, meaning that no such process can substantially develop in plasma at the PALS on the 675 keV resonance, not even in the most optimistic confinement scenarios. Nevertheless, we put forward for further investigation that more realistic conditions for setting up the avalanche regime could rather be attained by suitably targeting the narrow 163 keV resonance in the fusion cross section, also in connection to recently proposed laser-driven magnetic trapping techniques.

No evidence of persisting measles virus in peripheral blood mononuclear cells from children with autism spectrum disorder.

PubMed

D'Souza, Yasmin; Fombonne, Eric; Ward, Brian J

2006-10-01

Despite epidemiologic evidence to the contrary, claims of an association between measles-mumps-rubella vaccination and the development of autism have persisted. Such claims are based primarily on the identification of measles virus nucleic acids in tissues and body fluids by polymerase chain reaction. We sought to determine whether measles virus nucleic acids persist in children with autism spectrum disorder compared with control children. Peripheral blood mononuclear cells were isolated from 54 children with autism spectrum disorder and 34 developmentally normal children, and up to 4 real-time polymerase chain reaction assays and 2 nested polymerase chain reaction assays were performed. These assays targeted the nucleoprotein, fusion, and hemagglutinin genes of measles virus using previously published primer pairs with detection by SYBR green I. Our own real-time assay targeted the fusion gene using novel primers and an internal fluorescent probe. Positive reactions were evaluated rigorously, and amplicons were sequenced. Finally, anti-measles antibody titers were measured by enzyme immunoassay. The real-time assays based on previously published primers gave rise to a large number of positive reactions in both autism spectrum disorder and control samples. Almost all of the positive reactions in these assays were eliminated by evaluation of melting curves and amplicon band size. The amplicons for the remaining positive reactions were cloned and sequenced. No sample from either autism spectrum disorder or control groups was found to contain nucleic acids from any measles virus gene. In the nested polymerase chain reaction and in-house assays, none of the samples yielded positive results. Furthermore, there was no difference in anti-measles antibody titers between the autism and control groups. There is no evidence of measles virus persistence in the peripheral blood mononuclear cells of children with autism spectrum disorder.

Origin of a maximum of the astrophysical S factor in heavy-ion fusion reactions at deep subbarrier energies

NASA Astrophysics Data System (ADS)

Hagino, K.; Balantekin, A. B.; Lwin, N. W.; Thein, Ei Shwe Zin

2018-03-01

The hindrance phenomenon of heavy-ion fusion cross sections at deep subbarrier energies often accompanies a maximum of an astrophysical S factor at a threshold energy for fusion hindrance. We argue that this phenomenon can naturally be explained when the fusion excitation function is fitted with two potentials, with a larger (smaller) logarithmic slope at energies lower (higher) than the threshold energy. This analysis clearly suggests that the astrophysical S factor provides a convenient tool to analyze the deep subbarrier hindrance phenomenon, even though the S factor may have a strong energy dependence for heavy-ion systems unlike that for astrophysical reactions.

Towards a programme of testing and qualification for structural and plasma-facing materials in ‘fusion neutron’ environments

NASA Astrophysics Data System (ADS)

Stork, D.; Heidinger, R.; Muroga, T.; Zinkle, S. J.; Moeslang, A.; Porton, M.; Boutard, J.-L.; Gonzalez, S.; Ibarra, A.

2017-09-01

Materials damage by 14.1MeV neutrons from deuterium-tritium (D-T) fusion reactions can only be characterised definitively by subjecting a relevant configuration of test materials to high-intensity ‘fusion-neutron spectrum sources’, i.e. those simulating closely D-T fusion-neutron spectra. This provides major challenges to programmes to design and construct a demonstration fusion reactor prior to having a large-scale, high-intensity source of such neutrons. In this paper, we discuss the different aspects related to these ‘relevant configuration’ tests, including: • generic issues in materials qualification/validation, comparing safety requirements against those of investment protection; • lessons learned from the fission programme, enabling a reduced fusion materials testing programme; • the use and limitations of presently available possible irradiation sources to optimise a fusion neutron testing program including fission-neutron irradiation of isotopically and chemically tailored steels, ion damage by high-energy helium ions and self-ion beams, or irradiation studies with neutron sources of non-fusion spectra; and • the different potential sources of simulated fusion neutron spectra and the choice using stripping reactions from deuterium-beam ions incident on light-element targets.

New Evaluated Semi-Empirical Formula Using Optical Model for 14-15 MeV ( n, t) Reaction Cross Sections

NASA Astrophysics Data System (ADS)

Tel, E.; Durgu, C.; Aydın, A.; Bölükdemir, M. H.; Kaplan, A.; Okuducu, Ş.

2009-12-01

In the next century the world will face the need for new energy sources. Nuclear fusion can be one of the most attractive sources of energy from the viewpoint of safety and minimal environmental impact. Fusion will not produce CO2 or SO2 and thus will not contribute to global warming or acid rain. Achieving acceptable performance for a fusion power system in the areas of economics, safety and environmental acceptability, is critically dependent on performance of the blanket and diverter systems which are the primary heat recovery, plasma purification, and tritium breeding systems. Tritium self-sufficiency must be maintained for a commercial power plant. The hybrid reactor is a combination of the fusion and fission processes. For self-sustaining (D-T) fusion driver tritium breeding ratio should be greater than 1.05. So working out the systematics of ( n, t) reaction cross-sections are of great importance for the definition of the excitation function character for the given reaction taking place on various nuclei at energies up to 20 MeV. In this study, we have calculated non-elastic cross-sections by using optical model for ( n, t) reactions at 14-15 MeV energy. We have investigated the excitation function character and reaction Q-values depending on the asymmetry term effect for the ( n, t) reaction cross-sections. We have obtained new coefficients for the ( n, t) reaction cross-sections. We have suggested semi-empirical formulas including optical model nonelastic effects by fitting two parameters for the ( n, t) reaction cross-sections at 14-15 MeV. We have discussed the odd-even effect and the pairing effect considering binding energy systematic of the nuclear shell model for the new experimental data and new cross-sections formulas ( n, t) reactions developed by Tel et al. We have determined a different parameter groups by the classification of nuclei into even-even, even-odd and odd-even for ( n, t) reactions cross-sections. The obtained cross-section formulas with new coefficients have been discussed and compared with the available experimental data.

Sensitivity of the fusion cross section to the density dependence of the symmetry energy

NASA Astrophysics Data System (ADS)

Reinhard, P.-G.; Umar, A. S.; Stevenson, P. D.; Piekarewicz, J.; Oberacker, V. E.; Maruhn, J. A.

2016-04-01

Background: The study of the nuclear equation of state (EOS) and the behavior of nuclear matter under extreme conditions is crucial to our understanding of many nuclear and astrophysical phenomena. Nuclear reactions serve as one of the means for studying the EOS. Purpose: It is the aim of this paper to discuss the impact of nuclear fusion on the EOS. This is a timely subject given the expected availability of increasingly exotic beams at rare isotope facilities [A. B. Balantekin et al., Mod. Phys. Lett. A 29, 1430010 (2014), 10.1142/S0217732314300109]. In practice, we focus on 48Ca+48Ca fusion. Method: We employ three different approaches to calculate fusion cross sections for a set of energy density functionals with systematically varying nuclear matter properties. Fusion calculations are performed using frozen densities, using a dynamic microscopic method based on density-constrained time-dependent Hartree-Fock (DC-TDHF) approach, as well as direct TDHF study of above barrier cross sections. For these studies, we employ a family of Skyrme parametrizations with systematically varied nuclear matter properties. Results: The folding-potential model provides a reasonable first estimate of cross sections. DC-TDHF, which includes dynamical polarization, reduces the fusion barriers and delivers much better cross sections. Full TDHF near the barrier agrees nicely with DC-TDHF. Most of the Skyrme forces which we used deliver, on the average, fusion cross sections in good agreement with the data. Trying to read off a trend in the results, we find a slight preference for forces which deliver a slope of symmetry energy of L ≈50 MeV that corresponds to a neutron-skin thickness of 48Ca of Rskin=(0.180 -0.210 ) fm. Conclusions: Fusion reactions in the barrier and sub-barrier region can be a tool to study the EOS and the neutron skin of nuclei. The success of the approach will depend on reduced experimental uncertainties of fusion data as well as the development of fusion theories that closely couple to the microscopic structure and dynamics.

Fusion-fission Study at JAEA for Heavy-element Synthesis

NASA Astrophysics Data System (ADS)

Nishio, K.

Fission fragment mass distributions were measured in the heavy-ion induced fission using 238U target nucleus. The mass distribu- tions changed drastically with incident energy. The results are explained by a change of the ratio between fusion and qasifission with nuclear orientation. A calculation based on a fluctuation dissipation model reproduced the mass distributions and their inci- dent energy dependence. Fusion probability was determined in the analysis. Evaporation residue cross sections were calculated with a statistical model in the reactions of 30Si+238U and 34S+238U using the obtained fusion probability in the entrance channel. The results agree with the measured cross sections of 263,264Sg and 267,268Hs, produced by 30Si+238U and 34S+238U, respectively. It is also suggested that the sub-barrier energies can be used for heavy element synthesis.

Hot Fusion: an efficient method to clone multiple DNA fragments as well as inverted repeats without ligase.

PubMed

Fu, Changlin; Donovan, William P; Shikapwashya-Hasser, Olga; Ye, Xudong; Cole, Robert H

2014-01-01

Molecular cloning is utilized in nearly every facet of biological and medical research. We have developed a method, termed Hot Fusion, to efficiently clone one or multiple DNA fragments into plasmid vectors without the use of ligase. The method is directional, produces seamless junctions and is not dependent on the availability of restriction sites for inserts. Fragments are assembled based on shared homology regions of 17-30 bp at the junctions, which greatly simplifies the construct design. Hot Fusion is carried out in a one-step, single tube reaction at 50 °C for one hour followed by cooling to room temperature. In addition to its utility for multi-fragment assembly Hot Fusion provides a highly efficient method for cloning DNA fragments containing inverted repeats for applications such as RNAi. The overall cloning efficiency is in the order of 90-95%.

Hot Fusion: An Efficient Method to Clone Multiple DNA Fragments as Well as Inverted Repeats without Ligase

PubMed Central

Fu, Changlin; Donovan, William P.; Shikapwashya-Hasser, Olga; Ye, Xudong; Cole, Robert H.

2014-01-01

Molecular cloning is utilized in nearly every facet of biological and medical research. We have developed a method, termed Hot Fusion, to efficiently clone one or multiple DNA fragments into plasmid vectors without the use of ligase. The method is directional, produces seamless junctions and is not dependent on the availability of restriction sites for inserts. Fragments are assembled based on shared homology regions of 17–30 bp at the junctions, which greatly simplifies the construct design. Hot Fusion is carried out in a one-step, single tube reaction at 50°C for one hour followed by cooling to room temperature. In addition to its utility for multi-fragment assembly Hot Fusion provides a highly efficient method for cloning DNA fragments containing inverted repeats for applications such as RNAi. The overall cloning efficiency is in the order of 90–95%. PMID:25551825

Pulsed fusion space propulsion: Computational Magneto-Hydro Dynamics of a multi-coil parabolic reaction chamber

NASA Astrophysics Data System (ADS)

Romanelli, Gherardo; Mignone, Andrea; Cervone, Angelo

2017-10-01

Pulsed fusion propulsion might finally revolutionise manned space exploration by providing an affordable and relatively fast access to interplanetary destinations. However, such systems are still in an early development phase and one of the key areas requiring further investigations is the operation of the magnetic nozzle, the device meant to exploit the fusion energy and generate thrust. One of the last pulsed fusion magnetic nozzle design is the so called multi-coil parabolic reaction chamber: the reaction is thereby ignited at the focus of an open parabolic chamber, enclosed by a series of coaxial superconducting coils that apply a magnetic field. The field, beside confining the reaction and preventing any contact between hot fusion plasma and chamber structure, is also meant to reflect the explosion and push plasma out of the rocket. Reflection is attained thanks to electric currents induced in conductive skin layers that cover each of the coils, the change of plasma axial momentum generates thrust in reaction. This working principle has yet to be extensively verified and computational Magneto-Hydro Dynamics (MHD) is a viable option to achieve that. This work is one of the first detailed ideal-MHD analysis of a multi-coil parabolic reaction chamber of this kind and has been completed employing PLUTO, a freely distributed computational code developed at the Physics Department of the University of Turin. The results are thus a preliminary verification of the chamber's performance. Nonetheless, plasma leakage through the chamber structure has been highlighted. Therefore, further investigations are required to validate the chamber design. Implementing a more accurate physical model (e.g. Hall-MHD or relativistic-MHD) is thus mandatory, and PLUTO shows the capabilities to achieve that.

Energy-Based Tissue Fusion for Sutureless Closure: Applications, Mechanisms, and Potential for Functional Recovery.

PubMed

Kramer, Eric A; Rentschler, Mark E

2018-06-04

As minimally invasive surgical techniques progress, the demand for efficient, reliable methods for vascular ligation and tissue closure becomes pronounced. The surgical advantages of energy-based vessel sealing exceed those of traditional, compression-based ligatures in procedures sensitive to duration, foreign bodies, and recovery time alike. Although the use of energy-based devices to seal or transect vasculature and connective tissue bundles is widespread, the breadth of heating strategies and energy dosimetry used across devices underscores an uncertainty as to the molecular nature of the sealing mechanism and induced tissue effect. Furthermore, energy-based techniques exhibit promise for the closure and functional repair of soft and connective tissues in the nervous, enteral, and dermal tissue domains. A constitutive theory of molecular bonding forces that arise in response to supraphysiological temperatures is required in order to optimize and progress the use of energy-based tissue fusion. While rapid tissue bonding has been suggested to arise from dehydration, dipole interactions, molecular cross-links, or the coagulation of cellular proteins, long-term functional tissue repair across fusion boundaries requires that the reaction to thermal damage be tailored to catalyze the onset of biological healing and remodeling. In this review, we compile and contrast findings from published thermal fusion research in an effort to encourage a molecular approach to characterization of the prevalent and promising energy-based tissue bond.

Mass and angular distributions of the reaction products in heavy ion collisions

NASA Astrophysics Data System (ADS)

Nasirov, A. K.; Giardina, G.; Mandaglio, G.; Kayumov, B. M.; Tashkhodjaev, R. B.

2018-05-01

The optimal reactions and beam energies leading to synthesize superheavy elements is searched by studying mass and angular distributions of fission-like products in heavy-ion collisions since the evaporation residue cross section consists an ignorable small part of the fusion cross section. The intensity of the yield of fission-like products allows us to estimate the probability of the complete fusion of the interacting nuclei. The overlap of the mass and angular distributions of the fusion-fission and quasifission products causes difficulty at estimation of the correct value of the probability of the compound nucleus formation. A study of the mass and angular distributions of the reaction products is suitable key to understand the interaction mechanism of heavy ion collisions.

Coupled-channels analyses for 9,11Li + 208Pb fusion reactions with multi-neutron transfer couplings

NASA Astrophysics Data System (ADS)

Choi, Ki-Seok; Cheoun, Myung-Ki; So, W. Y.; Hagino, K.; Kim, K. S.

2018-05-01

We discuss the role of two-neutron transfer processes in the fusion reaction of the 9,11Li + 208Pb systems. We first analyze the 9Li + 208Pb reaction by taking into account the coupling to the 7Li + 210Pb channel. To this end, we assume that two neutrons are directly transferred to a single effective channel in 210Pb and solve the coupled-channels equations with the two channels. By adjusting the coupling strength and the effective Q-value, we successfully reproduce the experimental fusion cross sections for this system. We then analyze the 11Li + 208Pb reaction in a similar manner, that is, by taking into account three effective channels with 11Li + 208Pb, 9Li + 210Pb, and 7Li + 212Pb partitions. In order to take into account the halo structure of the 11Li nucleus, we construct the potential between 11Li and 208Pb with a double folding procedure, while we employ a Woods-Saxon type potential with the global Akyüz-Winther parameters for the other channels. Our calculation indicates that the multiple two-neutron transfer process plays a crucial role in the 11Li + 208Pb fusion reaction at energies around the Coulomb barrier.

Spin distributions and cross sections of evaporation residues in the 28Si+176Yb reaction

NASA Astrophysics Data System (ADS)

Sudarshan, K.; Tripathi, R.; Sodaye, S.; Sharma, S. K.; Pujari, P. K.; Gehlot, J.; Madhavan, N.; Nath, S.; Mohanto, G.; Mukul, I.; Jhingan, A.; Mazumdar, I.

2017-02-01

Background: Non-compound-nucleus fission in the preactinide region has been an active area of investigation in the recent past. Based on the measurements of fission-fragment mass distributions in the fission of 202Po, populated by reactions with varying entrance channel mass asymmetry, the onset of non-compound-nucleus fission was proposed to be around ZpZt˜1000 [Phys. Rev. C 77, 024606 (2008), 10.1103/PhysRevC.77.024606], where Zp and Zt are the projectile and target proton numbers, respectively. Purpose: The present paper is aimed at the measurement of cross sections and spin distributions of evaporation residues in the 28Si+176Yb reaction (ZpZt=980 ) to investigate the fusion hindrance which, in turn, would give information about the contribution from non-compound-nucleus fission in this reaction. Method: Evaporation-residue cross sections were measured in the beam energy range of 129-166 MeV using the hybrid recoil mass analyzer (HYRA) operated in the gas-filled mode. Evaporation-residue cross sections were also measured by the recoil catcher technique followed by off-line γ -ray spectrometry at few intermediate energies. γ -ray multiplicities of evaporation residues were measured to infer about their spin distribution. The measurements were carried out using NaI(Tl) detector-based 4π-spin spectrometer from the Tata Institute of Fundamental Research, Mumbai, coupled to the HYRA. Results: Evaporation-residue cross sections were significantly lower compared to those calculated using the statistical model code pace2 [Phys. Rev. C 21, 230 (1980), 10.1103/PhysRevC.21.230] with the coupled-channel fusion model code ccfus [Comput. Phys. Commun. 46, 187 (1987), 10.1016/0010-4655(87)90045-2] at beam energies close to the entrance channel Coulomb barrier. At higher beam energies, experimental cross sections were close to those predicted by the model. Average γ -ray multiplicities or angular momentum values of evaporation residues were in agreement with the calculations of the code ccfus + pace2 within the experimental uncertainties at all the beam energies. Conclusions: Deviation of evaporation-residue cross sections from the "fusion + statistical model" predictions at beam energies close to the entrance channel Coulomb barrier indicates fusion hindrance at these beam energies which would lead to non-compound-nucleus fission. However, reasonable agreement of average angular momentum values of evaporation residues at these beam energies with those calculated using the coupled-channel fusion model with the statistical model codes ccfus + pace2 suggests that fusion suppression at beam energies close to the entrance channel Coulomb barrier where populated l waves are low is not l dependent.

Line-Tension Controlled Mechanism for Influenza Fusion

PubMed Central

Risselada, Herre Jelger; Smirnova, Yuliya G.; Grubmüller, Helmut; Marrink, Siewert Jan; Müller, Marcus

2012-01-01

Our molecular simulations reveal that wild-type influenza fusion peptides are able to stabilize a highly fusogenic pre-fusion structure, i.e. a peptide bundle formed by four or more trans-membrane arranged fusion peptides. We rationalize that the lipid rim around such bundle has a non-vanishing rim energy (line-tension), which is essential to (i) stabilize the initial contact point between the fusing bilayers, i.e. the stalk, and (ii) drive its subsequent evolution. Such line-tension controlled fusion event does not proceed along the hypothesized standard stalk-hemifusion pathway. In modeled influenza fusion, single point mutations in the influenza fusion peptide either completely inhibit fusion (mutants G1V and W14A) or, intriguingly, specifically arrest fusion at a hemifusion state (mutant G1S). Our simulations demonstrate that, within a line-tension controlled fusion mechanism, these known point mutations either completely inhibit fusion by impairing the peptide’s ability to stabilize the required peptide bundle (G1V and W14A) or stabilize a persistent bundle that leads to a kinetically trapped hemifusion state (G1S). In addition, our results further suggest that the recently discovered leaky fusion mutant G13A, which is known to facilitate a pronounced leakage of the target membrane prior to lipid mixing, reduces the membrane integrity by forming a ‘super’ bundle. Our simulations offer a new interpretation for a number of experimentally observed features of the fusion reaction mediated by the prototypical fusion protein, influenza hemagglutinin, and might bring new insights into mechanisms of other viral fusion reactions. PMID:22761674

Processes in massive nuclei reactions and the way to complete fusion of reactants. What perspectives for the synthesis of heavier superheavy elements?

NASA Astrophysics Data System (ADS)

Mandaglio, G.; Nasirov, A. K.; Curciarello, F.; De Leo, V.; Romaniuk, M.; Fazio, G.; Giardina, G.

2012-12-01

By using the dinuclear system (DNS) model we determine the capture of reactants at the first stage of reaction, the competition between the DNS decay by the quasifission (QF) and the complete fusion (CF) process up to formation of the compound nucleus (CN) having compact shape. Further evolution of the CN is considered as its fission into two fragments or formation of evaporation residues (ER) by its cooling after emission of neutrons or/and charged light particles. Disappearance of the CN fission barrier due to its fast rotation leads to the fast fission (FF) by formation of fissionlike fragments. The results of calculations for the mass symmetric 136Xe+136Xe reaction, almost mass symmetric 108Mo+144Ba reaction, and mass asymmetric like 24Mg+238U and 34S+248Cm reactions are discussed. The fusion probability PCN calculated for many massive nuclei reactions leading to formation of superheavy nuclei have been analyzed. The reactions which can lead in perspective to the synthesis of superheavy elements in the Z = 120 - 126 range and, eventually, also to heaviest nuclei, are discussed.

SU-D-304-07: Application of Proton Boron Fusion Reaction to Radiation Therapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jung, J; Yoon, D; Shin, H

Purpose: we present the introduction of a therapy method using the proton boron fusion reaction. The purpose of this study is to verify the theoretical validity of proton boron fusion therapy using Monte Carlo simulations. Methods: After boron is accumulated in the tumor region, the emitted from outside the body proton can react with the boron in the tumor region. An increase of the proton’s maximum dose level is caused by the boron and only the tumor cell is damaged more critically. In addition, a prompt gamma ray is emitted from the proton boron reaction point. Here we show thatmore » the effectiveness of the proton boron fusion therapy (PBFT) was verified using Monte Carlo simulations. Results: We found that a dramatic increase by more than half of the proton’s maximum dose level was induced by the boron in the tumor region. This increase occurred only when the proton’s maximum dose point was located within the boron uptake region (BUR). In addition, the 719 keV prompt gamma ray peak produced by the proton boron fusion reaction was positively detected. Conclusion: This therapy method features the advantages such as the application of Bragg-peak to the therapy, the accurate targeting of tumor, improved therapy effects, and the monitoring of the therapy region during treatment.« less

Screening for diverse PDGFRA or PDGFRB fusion genes is facilitated by generic quantitative reverse transcriptase polymerase chain reaction analysis

PubMed Central

Erben, Philipp; Gosenca, Darko; Müller, Martin C.; Reinhard, Jelena; Score, Joannah; del Valle, Francesco; Walz, Christoph; Mix, Jürgen; Metzgeroth, Georgia; Ernst, Thomas; Haferlach, Claudia; Cross, Nicholas C.P.; Hochhaus, Andreas; Reiter, Andreas

2010-01-01

Background Rapid identification of diverse fusion genes with involvement of PDGFRA or PDGFRB in eosinophilia-associated myeloproliferative neoplasms is essential for adequate clinical management but is complicated by the multitude and heterogeneity of partner genes and breakpoints. Design and Methods We established a generic quantitative reverse transcriptase polymerase chain reaction to detect overexpression of the 3′-regions of PDGFRA or PDGFRB as a possible indicator of an underlying fusion. Results At diagnosis, all patients with known fusion genes involving PDGFRA (n=5; 51 patients) or PDGFRB (n=5; 7 patients) showed significantly increased normalized expression levels compared to 191 patients with fusion gene-negative eosinophilia or healthy individuals (PDGFRA/ABL: 0.73 versus 0.0066 versus 0.0064, P<0.0001; PDGFRB/ABL: 196 versus 3.8 versus 5.85, P<0.0001). The sensitivity and specificity of the activation screening test were, respectively, 100% and 88.4% for PDGFRA and 100% and 94% for PDGFRB. Furthermore, significant overexpression of PDGFRB was found in a patient with an eosinophilia-associated myeloproliferative neoplasm with uninformative cytogenetics and an excellent response to imatinib. Subsequently, a new SART3-PDGFRB fusion gene was identified by 5′-rapid amplification of cDNA ends polymerase chain reaction (5′-RACE-PCR). Conclusions Quantitative reverse transcriptase polymerase chain reaction analysis is a simple and useful adjunct to standard diagnostic assays to detect clinically significant overexpression of PDGFRA and PDGFRB in eosinophilia-associated myeloproliferative neoplasms or related disorders. PMID:20107158

Low-energy nuclear reaction of the 14N+169Tm system: Incomplete fusion

NASA Astrophysics Data System (ADS)

Kumar, R.; Sharma, Vijay R.; Yadav, Abhishek; Singh, Pushpendra P.; Agarwal, Avinash; Appannababu, S.; Mukherjee, S.; Singh, B. P.; Ali, R.; Bhowmik, R. K.

2017-11-01

Excitation functions of reaction residues produced in the 14N+169Tm system have been measured to high precision at energies above the fusion barrier, ranging from 1.04 VB to 1.30 VB , and analyzed in the framework of the statistical model code pace4. Analysis of α -emitting channels points toward the onset of incomplete fusion even at slightly above-barrier energies where complete fusion is supposed to be one of the dominant processes. The onset and strength of incomplete fusion have been deduced and studied in terms of various entrance channel parameters. Present results together with the reanalysis of existing data for various projectile-target combinations conclusively suggest strong influence of projectile structure on the onset of incomplete fusion. Also, a strong dependence on the Coulomb effect (ZPZT) has been observed for the present system along with different projectile-target combinations available in the literature. It is concluded that the fraction of incomplete fusion linearly increases with ZPZT and is found to be more for larger ZPZT values, indicating significantly important linear systematics.

Controlled Nuclear Fusion.

ERIC Educational Resources Information Center

Glasstone, Samuel

This publication is one of a series of information booklets for the general public published by The United States Atomic Energy Commission. Among the topics discussed are: Importance of Fusion Energy; Conditions for Nuclear Fusion; Thermonuclear Reactions in Plasmas; Plasma Confinement by Magnetic Fields; Experiments With Plasmas; High-Temperature…

Slow fusion pore expansion creates a unique reaction chamber for co-packaged cargo

PubMed Central

Bittner, Mary A.; Lawrence, Daniel A.

2017-01-01

A lumenal secretory granule protein, tissue plasminogen activator (tPA), greatly slows fusion pore dilation and thereby slows its own discharge. We investigated another outcome of the long-lived narrow fusion pore: the creation of a nanoscale chemical reaction chamber for granule contents in which the pH is suddenly neutralized upon fusion. Bovine adrenal chromaffin cells endogenously express both tPA and its primary protein inhibitor, plasminogen activator inhibitor 1 (PAI). We found by immunocytochemistry that tPA and PAI are co-packaged in the same secretory granule. It is known that PAI irreversibly and covalently inactivates tPA at neutral pH. We demonstrate with zymography that the acidic granule lumen protects tPA from inactivation by PAI. Immunocytochemistry, total internal reflection fluorescence (TIRF) microscopy, and polarized TIRF microscopy demonstrated that co-packaged PAI and tPA remain together in granules for many seconds in the nanoscale reaction chamber, more than enough time to inhibit tPA and create a new secreted protein species. PMID:28882880

The ^132Sn + ^96Zr reaction: a study of fusion enhancement/hindrance

NASA Astrophysics Data System (ADS)

Loveland, Walter; Vinodkumar, A. M.; Neeway, James; Sprunger, Peter; Prisbrey, Landon; Peterson, Donald; Liang, J. F.; Shapira, Dan; Gross, C. J.; Varner, R. L.; Kolata, J. J.; Roberts, A.; Caraley, A. L.

2008-10-01

Capture-fission cross sections were measured for the collision of the massive nucleus ^132Sn with ^96Zr at center of mass energies ranging from 192.8 to 249.6 MeV in an attempt to study fusion enhancement and hindrance in this reaction involving very neutron-rich nuclei. Coincident fission fragments were detected using silicon detectors. Using angle and energy conditions, deep inelastic scattering events were separated from fission events. Coupled channels calculations can describe the data if the surface diffuseness parameter, a, is allowed to be 1.10 fm, instead of the customary 0.6 fm. The measured capture-fission cross sections agree moderately well with model calculations using the dinuclear system (DNS) model. If we use this model to predict fusion barrier heights for these reactions, we find the predicted fusion hindrance, as represented by the extra push energy, is greater for the more neutron-rich system, lessening the advantage of the lower interaction barriers with neutron rich projectiles.

132Sn+96Zr reaction: A study of fusion enhancement/hindrance

NASA Astrophysics Data System (ADS)

Vinodkumar, A. M.; Loveland, W.; Neeway, J. J.; Prisbrey, L.; Sprunger, P. H.; Peterson, D.; Liang, J. F.; Shapira, D.; Gross, C. J.; Varner, R. L.; Kolata, J. J.; Roberts, A.; Caraley, A. L.

2008-11-01

Capture-fission cross sections were measured for the collision of the massive nucleus Sn132 with Zr96 at center-of-mass energies ranging from 192.8 to 249.6 MeV in an attempt to study fusion enhancement and hindrance in this reaction involving very neutron-rich nuclei. Coincident fission fragments were detected using silicon detectors. Using angle and energy conditions, deep inelastic scattering events were separated from fission events. Coupled-channels calculations can describe the data if the surface diffuseness parameter, a, is allowed to be 1.10 fm instead of the customary 0.6 fm. The measured capture-fission cross sections agree moderately well with model calculations using the dinuclear system model. If we use this model to predict fusion barrier heights for these reactions, we find the predicted fusion hindrance, as represented by the extra push energy, is greater for the more neutron-rich system, lessening the advantage of the lower interaction barriers with neutron-rich projectiles.

Enhancement of cold fusion in metal ``hydrides'' by screening of proton and deuteron charges

NASA Astrophysics Data System (ADS)

Burrows, Adam

1989-08-01

The production of fusion heat in a metal hydride (deuteride) lattice is problematic, since the reported ratio of power to neutron or γ-ray flux of some workers is much larger than that for any known conventional complement of fusion reactions. However, enhanced screening of the deuteron or proton charge in the lattice cages might enhance to modest levels the standard d+d-->3He+n,T+p and p+d-->3He+γ fusion reactions. By lowering the effective deuteron-deuteron and proton-deuteron Coulomb barriers, the effective Gamov penetration factor is increased substantially in metals in general, transition metals in particular, and perhaps enough to produce modest neutron fluxes and tritium yields.

Dynamin Regulates Specific Membrane Fusion Events Necessary for Acrosomal Exocytosis in Mouse Spermatozoa

PubMed Central

Reid, Andrew T.; Lord, Tessa; Stanger, Simone J.; Roman, Shaun D.; McCluskey, Adam; Robinson, Phillip J.; Aitken, R. John; Nixon, Brett

2012-01-01

Mammalian spermatozoa must complete an acrosome reaction prior to fertilizing an oocyte. The acrosome reaction is a unique exocytotic event involving a series of prolonged membrane fusions that ultimately result in the production of membrane vesicles and release of the acrosomal contents. This event requires the concerted action of a large number of fusion-competent signaling and scaffolding proteins. Here we show that two different members of the dynamin GTPase family localize to the developing acrosome of maturing mouse germ cells. Both dynamin 1 and 2 also remain within the periacrosomal region of mature mouse spermatozoa and are thus well positioned to regulate the acrosome reaction. Two pharmacological inhibitors of dynamin, dynasore and Dyngo-4a, blocked the in vitro induction of acrosomal exocytosis by progesterone, but not by the calcium ionophore A23187, and elicited a concomitant reduction of in vitro fertilization. In vivo treatment with these inhibitors also resulted in spermatozoa displaying reduced acrosome reaction potential. Dynamin 1 and 2 phosphorylation increased on progesterone treatment, and this was also selectively blocked by dynasore. On the basis of our collective data, we propose that dynamin could regulate specific membrane fusion events necessary for acrosomal exocytosis in mouse spermatozoa. PMID:22977254

Magnetized Target Fusion

NASA Technical Reports Server (NTRS)

Griffin, Steven T.

2002-01-01

Magnetized target fusion (MTF) is under consideration as a means of building a low mass, high specific impulse, and high thrust propulsion system for interplanetary travel. This unique combination is the result of the generation of a high temperature plasma by the nuclear fusion process. This plasma can then be deflected by magnetic fields to provide thrust. Fusion is initiated by a small traction of the energy generated in the magnetic coils due to the plasma's compression of the magnetic field. The power gain from a fusion reaction is such that inefficiencies due to thermal neutrons and coil losses can be overcome. Since the fusion reaction products are directly used for propulsion and the power to initiate the reaction is directly obtained from the thrust generation, no massive power supply for energy conversion is required. The result should be a low engine mass, high specific impulse and high thrust system. The key is to successfully initiate fusion as a proof-of-principle for this application. Currently MSFC is implementing MTF proof-of-principle experiments. This involves many technical details and ancillary investigations. Of these, selected pertinent issues include the properties, orientation and timing of the plasma guns and the convergence and interface development of the "pusher" plasma. Computer simulations of the target plasma's behavior under compression and the convergence and mixing of the gun plasma are under investigation. This work is to focus on the gun characterization and development as it relates to plasma initiation and repeatability.

Three-dimensional modeling of the neutron spectrum to infer plasma conditions in cryogenic inertial confinement fusion implosions

NASA Astrophysics Data System (ADS)

Weilacher, F.; Radha, P. B.; Forrest, C.

2018-04-01

Neutron-based diagnostics are typically used to infer compressed core conditions such as areal density and ion temperature in deuterium-tritium (D-T) inertial confinement fusion (ICF) implosions. Asymmetries in the observed neutron-related quantities are important to understanding failure modes in these implosions. Neutrons from fusion reactions and their subsequent interactions including elastic scattering and neutron-induced deuteron breakup reactions are tracked to create spectra. It is shown that background subtraction is important for inferring areal density from backscattered neutrons and is less important for the forward-scattered neutrons. A three-dimensional hydrodynamic simulation of a cryogenic implosion on the OMEGA Laser System [Boehly et al., Opt. Commun. 133, 495 (1997)] using the hydrodynamic code HYDRA [Marinak et al., Phys. Plasmas 8, 2275 (2001)] is post-processed using the tracking code IRIS3D. It is shown that different parts of the neutron spectrum from the view can be mapped into different regions of the implosion, enabling an inference of an areal-density map. It is also shown that the average areal-density and an areal-density map of the compressed target can be reconstructed with a finite number of detectors placed around the target chamber. Ion temperatures are inferred from the width of the D-D and D-T fusion neutron spectra. Backgrounds can significantly alter the inferred ion temperatures from the D-D reaction, whereas they insignificantly influence the inferred D-T ion temperatures for the areal densities typical of OMEGA implosions. Asymmetries resulting in fluid flow in the core are shown to influence the absolute inferred ion temperatures from both reactions, although relative inferred values continue to reflect the underlying asymmetry pattern. The work presented here is part of the wide range of the first set of studies performed with IRIS3D. This code will continue to be used for post-processing detailed hydrodynamic simulations and interpreting observed neutron spectra in ICF implosions.

Nuclear Reactions in Micro/Nano-Scale Metal Particles

NASA Astrophysics Data System (ADS)

Kim, Y. E.

2013-03-01

Low-energy nuclear reactions in micro/nano-scale metal particles are described based on the theory of Bose-Einstein condensation nuclear fusion (BECNF). The BECNF theory is based on a single basic assumption capable of explaining the observed LENR phenomena; deuterons in metals undergo Bose-Einstein condensation. The BECNF theory is also a quantitative predictive physical theory. Experimental tests of the basic assumption and theoretical predictions are proposed. Potential application to energy generation by ignition at low temperatures is described. Generalized theory of BECNF is used to carry out theoretical analyses of recently reported experimental results for hydrogen-nickel system.

Dynamical approach to heavy-ion induced fusion using actinide target

NASA Astrophysics Data System (ADS)

Aritomo, Y.; Hagino, K.; Chiba, S.; Nishio, K.

2012-10-01

To treat heavy-ion reactions using actinide target nucleus, we propose a model which takes into account the coupling to the collective states of interacting nuclei in the penetration of the Coulomb barrier and the dynamical evolution of nuclear shape from the contact configuration. A fluctuation-dissipation model (Langevin equation) was applied in the dynamical calculation, where effect of nuclear orientation at the initial impact on the prolately deformed target nucleus was considered. Using this model, we analyzed the experimental data for the mass distribution of fission fragments (MDFF) in the reaction of 36S+238U at several incident energies. Fusion-fission, quasifission and deep-quasi-fission are separated as different trajectories on the potential energy surface. We estimated the fusion cross section of the reaction.

Development of an inertial confinement fusion platform to study charged-particle-producing nuclear reactions relevant to nuclear astrophysics

DOE PAGES

Gatu Johnson, M.; Zylstra, A. B.; Bacher, A.; ...

2017-03-28

Here, this paper describes the development of a platform to study astrophysically relevant nuclear reactions using inertial-confinement fusion implosions on the OMEGA and National Ignition Facility laser facilities, with a particular focus on optimizing the implosions to study charged-particle- producing reactions. Primary requirements on the platform are high yield, for high statistics in the fusion product measurements, combined with low areal density, to allow the charged fusion products to escape. This is optimally achieved with direct-drive exploding pusher implosions using thin-glass-shell capsules. Mitigation strategies to eliminate a possible target sheath potential which would accelerate the emitted ions are discussed. Themore » potential impact of kinetic effects on the implosions is also considered. The platform is initially employed to study the complementary T(t,2n)α, T( 3He,np)α and 3He( 3He,2p)α reactions. Proof-of-principle results from the first experiments demonstrating the ability to accurately measure the energy and yields of charged particles are presented. Lessons learned from these experiments will be used in studies of other reactions. Ultimately, the goals are to explore thermonuclear reaction rates and fundamental nuclear physics in stellarlike plasma environments, and to push this new frontier of nuclear astrophysics into unique regimes not reachable through existing platforms, with thermal ion velocity distributions, plasma screening, and low reactant energies.« less

Development of an inertial confinement fusion platform to study charged-particle-producing nuclear reactions relevant to nuclear astrophysics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gatu Johnson, M.; Zylstra, A. B.; Bacher, A.

Here, this paper describes the development of a platform to study astrophysically relevant nuclear reactions using inertial-confinement fusion implosions on the OMEGA and National Ignition Facility laser facilities, with a particular focus on optimizing the implosions to study charged-particle- producing reactions. Primary requirements on the platform are high yield, for high statistics in the fusion product measurements, combined with low areal density, to allow the charged fusion products to escape. This is optimally achieved with direct-drive exploding pusher implosions using thin-glass-shell capsules. Mitigation strategies to eliminate a possible target sheath potential which would accelerate the emitted ions are discussed. Themore » potential impact of kinetic effects on the implosions is also considered. The platform is initially employed to study the complementary T(t,2n)α, T( 3He,np)α and 3He( 3He,2p)α reactions. Proof-of-principle results from the first experiments demonstrating the ability to accurately measure the energy and yields of charged particles are presented. Lessons learned from these experiments will be used in studies of other reactions. Ultimately, the goals are to explore thermonuclear reaction rates and fundamental nuclear physics in stellarlike plasma environments, and to push this new frontier of nuclear astrophysics into unique regimes not reachable through existing platforms, with thermal ion velocity distributions, plasma screening, and low reactant energies.« less

Revised analysis of Ca 40 + Zr 96 fusion reactions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Esbensen, H.; Montagnoli, G.; Stefanini, A. M.

2016-03-10

Fusion data for 40Ca + 96Zr are analyzed by coupled-channels calculations that are based on a standard Woods-Saxon potential and include couplings to multiphonon excitations and transfer channels. The couplings to multiphonon excitations are the same as those used in a previous work. The transfer couplings are calibrated to reproduce the measured neutron transfer data. This type of calculation gives a poor fit to the fusion data. However, by multiplying the transfer couplings with a √2 one obtains an excellent fit. Finally, the scaling of the transfer strengths is supposed to simulate the combined effect of neutron and proton transfer,more » and the calculated one- and two-nucleon transfer cross sections are indeed in reasonable agreement with the measured cross sections.« less

Bringing functions together with fusion enzymes--from nature's inventions to biotechnological applications.

PubMed

Elleuche, Skander

2015-02-01

It is a mammoth task to develop a modular protein toolbox enabling the production of posttranslational organized multifunctional enzymes that catalyze reactions in complex pathways. However, nature has always guided scientists to mimic evolutionary inventions in the laboratory and, nowadays, versatile methods have been established to experimentally connect enzymatic activities with multiple advantages. Among the oldest known natural examples is the linkage of two or more juxtaposed proteins catalyzing consecutive, non-consecutive, or opposing reactions by a native peptide bond. There are multiple reasons for the artificial construction of such fusion enzymes including improved catalytic activities, enabled substrate channelling by proximity of biocatalysts, higher stabilities, and cheaper production processes. To produce fused proteins, it is either possible to genetically fuse coding open reading frames or to connect proteins in a posttranslational process. Molecular biology techniques that have been established for the production of end-to-end or insertional fusions include overlap extension polymerase chain reaction, cloning, and recombination approaches. Depending on their flexibility and applicability, these methods offer various advantages to produce fusion genes in high throughput, different orientations, and including linker sequences to maximize the flexibility and performance of fusion partners. In this review, practical techniques to fuse genes are highlighted, enzymatic parameters to choose adequate enzymes for fusion approaches are summarized, and examples with biotechnological relevance are presented including a focus on plant biomass-degrading glycosyl hydrolases.

Remodeling of the notochord during development of vertebral fusions in Atlantic salmon (Salmo salar).

PubMed

Ytteborg, Elisabeth; Torgersen, Jacob Seilø; Pedersen, Mona E; Baeverfjord, Grete; Hannesson, Kirsten O; Takle, Harald

2010-12-01

Histological characterization of spinal fusions in Atlantic salmon (Salmo salar) has demonstrated shape alterations of vertebral body endplates, a reduced intervertebral space, and replacement of intervertebral cells by ectopic bone. However, the significance of the notochord during the fusion process has not been addressed. We have therefore investigated structural and cellular events in the notochord during the development of vertebral fusions. In order to induce vertebral fusions, Atlantic salmon were exposed to elevated temperatures from fertilization until they attained a size of 15g. Based on results from radiography, intermediate and terminal stages of the fusion process were investigated by immunohistochemistry and real-time quantitative polymerase chain reaction. Examination of structural extracellular matrix proteins such as Perlecan, Aggrecan, Elastin, and Laminin revealed reduced activity and reorganization at early stages in the pathology. Staining for elastic fibers visualized a thinner elastic membrane surrounding the notochord of developing fusions, and immunohistochemistry for Perlecan showed that the notochordal sheath was stretched during fusion. These findings in the outer notochord correlated with the loss of Aggrecan- and Substance-P-positive signals and the further loss of vacuoles from the chordocytes in the central notochord. At more progressed stages of fusion, chordocytes condensed, and the expression of Aggrecan and Substance P reappeared. The hyperdense regions seem to be of importance for the formation of notochordal tissue into bone. Thus, the remodeling of notochord integrity by reduced elasticity, structural alterations, and cellular changes is probably involved in the development of vertebral fusions.

A novel EML4-ALK variant: exon 6 of EML4 fused to exon 19 of ALK.

PubMed

Penzel, Roland; Schirmacher, Peter; Warth, Arne

2012-07-01

Cytotoxic chemotherapy remains the mainstay of treatment for most patients with advanced disease. Recently, anaplastic lymphoma kinase (ALK) expression as a major target for successful treatment with ALK inhibitors was detected in a subset of non-small-cell lung carcinomas, usually as a result of echinoderm microtubule-associated protein-like 4 (EML4)-ALK rearrangements. Although the chromosomal breakpoint within the EML4 gene varied, the breakpoint within ALK was most frequently reported within intron 19 or rarely in exon 20. Therefore, the different EML4-ALK variants so far contain the same 3' portion of ALK starting with exon 20. Here, we report a novel EML4-ALK variant detected by reverse transcription polymerase chain reaction analysis. Subsequent sequencing revealed an EML4-ALK fusion variant in which exon 6 of EML4 was fused to exon 19 of ALK. It occurred in a predominant solid pulmonary adenocarcinoma of a 65-year-old woman with a clear split signal of ALK in fluorescence in situ hybridization analysis and a weakly homogeneous ALK expression in immunohistochemical staining. Because of the growing number of fusion variants a primary reverse transcription polymerase chain reaction-based screening for ALK-positive non-small-cell lung carcinoma patients may not be sufficient for predictive diagnostics but transcript-based approaches and sequencing of ALK fusion variants might finally contribute to an optimized selection of patients.

Observed side feeding in incomplete fusion dynamics in 16O + 160Gd reaction at energy ∼5.6 MeV/A: Spin distribution measurements

NASA Astrophysics Data System (ADS)

Ali, Rahbar; Afzal Ansari, M.; Singh, D.; Kumar, Rakesh; Singh, D. P.; Sharma, M. K.; Gupta, Unnati; Singh, B. P.; Shidling, P. D.; Negi, Dinesh; Muralithar, S.; Singh, R. P.; Bhowmik, R. K.

2017-12-01

Spin distributions of various residues populated via complete fusion (CF) and incomplete fusion (ICF) reactions in the interaction of 16O with 160Gd at the projectile energy Eproj ∼ 5.6 MeV/A have been studied. The experimentally measured spin distributions of the residues associated with the ICF reactions are found to be distinctly different from those populated via the CF reactions. An attempt has been made to extract the side-feeding pattern from the spin distributions of CF and ICF reaction products. It has been observed that the CF products are strongly fed over a broad spin range. But, no side-feeding takes place in the low observed spins as low partial waves are strongly hindered in the fast α-emission channels (associated with ICF) in the forward direction. It has also been observed that the mean input angular momentum for direct α-emitting (ICF) channels is relatively higher than evaporation α-emitting (CF) channels, and it increases with direct α-multiplicity in forward direction.

Low energy cross sections and underground laboratories

NASA Astrophysics Data System (ADS)

Corvisiero, P.; LUNA Collaboration

2005-04-01

It is known that the chemical elements and their isotopes were created by nuclear fusion reactions in the hot interiors of remote and long-vanished stars over many billions of years [C. Rolfs, W.S. Rodney, Cauldrons in the cosmos, University of Ghicago Press, Chicago (1988)]. The present picture is that all elements from carbon to uranium have been produced entirely within stars during their fiery lifetimes and explosive deaths. The detailed understanding of the origin of the chemical elements and their isotopes combines astrophysics and nuclear physics, and forms what is called nuclear astrophysics. In turn, nuclear reactions are at the heart of nuclear astrophysics: they influence sensitively the nucleosynthesis of the elements in the earliest stages of the universe and in all the objects formed thereafter, and control the associated energy generation, neutrino luminosity, and evolution of stars. A good knowledge of the rates of these fusion reactions is essential to understanding this broad picture. Some of the most important experimental techniques to measure the corresponding cross sections, based both on direct and indirect methods, will be described in this paper.

Developing the Pulsed Fission-Fusion (PuFF) Engine

NASA Technical Reports Server (NTRS)

Adams, Robert B.; Cassibry, Jason; Bradley, David; Fabisinski, Leo; Statham, Geoffrey

2014-01-01

In September 2013 the NASA Innovative Advanced Concept (NIAC) organization awarded a phase I contract to the PuFF team. Our phase 1 proposal researched a pulsed fission-fusion propulsion system that compressed a target of deuterium (D) and tritium (T) as a mixture in a column, surrounded concentrically by Uranium. The target is surrounded by liquid lithium. A high power current would flow down the liquid lithium and the resulting Lorentz force would compress the column by roughly a factor of 10. The compressed column would reach criticality and a combination of fission and fusion reactions would occur. Our Phase I results, summarized herein, review our estimates of engine and vehicle performance, our work to date to model the fission-fusion reaction, and our initial efforts in experimental analysis.

Real-time processing of dual band HD video for maintaining operational effectiveness in degraded visual environments

NASA Astrophysics Data System (ADS)

Parker, Steve C. J.; Hickman, Duncan L.; Smith, Moira I.

2015-05-01

Effective reconnaissance, surveillance and situational awareness, using dual band sensor systems, require the extraction, enhancement and fusion of salient features, with the processed video being presented to the user in an ergonomic and interpretable manner. HALO™ is designed to meet these requirements and provides an affordable, real-time, and low-latency image fusion solution on a low size, weight and power (SWAP) platform. The system has been progressively refined through field trials to increase its operating envelope and robustness. The result is a video processor that improves detection, recognition and identification (DRI) performance, whilst lowering operator fatigue and reaction times in complex and highly dynamic situations. This paper compares the performance of HALO™, both qualitatively and quantitatively, with conventional blended fusion for operation in degraded visual environments (DVEs), such as those experienced during ground and air-based operations. Although image blending provides a simple fusion solution, which explains its common adoption, the results presented demonstrate that its performance is poor compared to the HALO™ fusion scheme in DVE scenarios.

Fast Pb-glass neutron-to-light converter for ICF (Inertial Confinement Fusion) target burn history measurements

NASA Astrophysics Data System (ADS)

Lerche, R. A.; Cable, M. D.; Phillion, D. W.

1990-09-01

We are developing a streak camera based instrument to diagnose the fusion reaction rate (burn history) within laser-driven ICF targets filled with D-T fuel. Recently, we attempted measurements using the 16.7 MeV gamma ray emitted in the T(d,gamma)He(5) fusion reaction. Pb glass which has a large cross section for pair production acts as a gamma-ray-to-light converter. Gamma rays interact within the glass to form electron-positron pairs that produce large amounts (1000 photons/gamma ray) of prompt (less than 10 ps) Cerenkov light as they slow down. In our experimental instrument, an f/10 Cassegrain telescope optically couples light produced within the converter to a streak camera having 20-ps resolution. Experiments using high-yield (10(exp 13) D-T neutrons), direct-drive targets at Nova produced good signals with widths of 200 ps. Time-of-flight measurements show the signals to be induced by neutrons rather than gamma rays. The Pb glass appears to act as a fast neutron-to-light converter. We continue to study the interactions process and the possibility of using the 16.7 MeV gamma rays for burn time measurements.

Fusion-fission and quasifission in the reactions with heavy ions leading to the formation of Hs

NASA Astrophysics Data System (ADS)

Itkis, I. M.; Itkis, M. G.; Knyazheva, G. N.; Kozulin, E. M.

2012-10-01

Mass and energy distributions of binary reaction products obtained in the reactions 22Ne+249Cf,26Mg+248Cm,36S+238U and 58Fe+208Pb leading to Hs isotopes have been measured. At energies below the Coulomb barrier the bimodal fission of Hs*, formed in the reaction 26Mg+248Cm, is observed. In the reaction 36S+238U the considerable part of the symmetric fragments arises from the quasifission process. At energies above the Coulomb barrier the symmetric fragments originate mainly from fusion-fission process for both reactions with Mg and S ions. In the case of the 58Fe+208Pb reaction the quasifission process dominates at all measured energies. The pre- and post-scission neutron multiplicities as a function of the fragment mass have been obtained for the reactions studied.

The cross sections of fusion-evaporation reactions: the most promising route to superheavy elements beyond Z=118

NASA Astrophysics Data System (ADS)

Jadambaa, Khuyagbaatar

2017-11-01

The synthesis of superheavy elements beyond oganesson (Og), which has atomic number Z = 118, is currently one of the main topics in nuclear physics. An absence of sufficient amounts of target material with atomic numbers heavier than californium (Z = 98) forces the use of projectiles heavier than 48Ca (Z = 20), which has been successfully used for the discoveries of elements with Z = 114 - 118 in complete fusion reactions. Experimental cross sections of 48Ca with actinide targets behave very differently to "cold" and "hot" fusion-evaporation reactions, where doubly-magic lead and deformed actinides are used as targets, respectively. The known cross sections of these reactions have been analysed compared to calculated fission barriers. It has been suggested that observed discrepancies between the cross sections of 48Ca-induced and other fusionevaporation reactions originate from the shell structure of the compound nucleus, which lies in the island of the stability. Besides scarcely known data on other reactions involving heavier projectiles, the most promising projectile for the synthesis of the elements beyond Og seems to be 50Ti. However, detailed studies of 50Ti, 54Cr, 58Fe and 64Ni-induced reactions are necessary to be performed in order to fully understand the complexities of superheavy element formation.

Sub-barrier quasifission in heavy element formation reactions with deformed actinide target nuclei

NASA Astrophysics Data System (ADS)

Hinde, D. J.; Jeung, D. Y.; Prasad, E.; Wakhle, A.; Dasgupta, M.; Evers, M.; Luong, D. H.; du Rietz, R.; Simenel, C.; Simpson, E. C.; Williams, E.

2018-02-01

Background: The formation of superheavy elements (SHEs) by fusion of two massive nuclei is severely inhibited by the competing quasifission process. Low excitation energies favor SHE survival against fusion-fission competition. In "cold" fusion with spherical target nuclei near 208Pb, SHE yields are largest at beam energies significantly below the average capture barrier. In "hot" fusion with statically deformed actinide nuclei, this is not the case. Here the elongated deformation-aligned configurations in sub-barrier capture reactions inhibits fusion (formation of a compact compound nucleus), instead favoring rapid reseparation through quasifission. Purpose: To determine the probabilities of fast and slow quasifission in reactions with prolate statically deformed actinide nuclei, through measurement and quantitative analysis of the dependence of quasifission characteristics at beam energies spanning the average capture barrier energy. Methods: The Australian National University Heavy Ion Accelerator Facility and CUBE fission spectrometer have been used to measure fission and quasifission mass and angle distributions for reactions with projectiles from C to S, bombarding Th and U target nuclei. Results: Mass-asymmetric quasifission occurring on a fast time scale, associated with collisions with the tips of the prolate actinide nuclei, shows a rapid increase in probability with increasing projectile charge, the transition being centered around projectile atomic number ZP=14 . For mass-symmetric fission events, deviations of angular anisotropies from expectations for fusion fission, indicating a component of slower quasifission, suggest a similar transition, but centered around ZP˜8 . Conclusions: Collisions with the tips of statically deformed prolate actinide nuclei show evidence for two distinct quasifission processes of different time scales. Their probabilities both increase rapidly with the projectile charge. The probability of fusion can be severely suppressed by these two quasifission processes, since the sub-barrier heavy element yield is likely to be determined by the product of the probabilities of surviving each quasifission process.

Fusion cross sections measurements with MUSIC

NASA Astrophysics Data System (ADS)

Carnelli, P. F. F.; Fernández Niello, J. O.; Almaraz-Calderon, S.; Rehm, K. E.; Albers, M.; Digiovine, B.; Esbensen, H.; Henderson, D.; Jiang, C. L.; Nusair, O.; Palchan-Hazan, T.; Pardo, R. C.; Ugalde, C.; Paul, M.; Alcorta, M.; Bertone, P. F.; Lai, J.; Marley, S. T.

2014-09-01

The interaction between exotic nuclei plays an important role for understanding the reaction mechanism of the fusion processes as well as for the energy production in stars. With the advent of radioactive beams new frontiers for fusion reaction studies have become accessible. We have performed the first measurements of the total fusion cross sections in the systems 10 , 14 , 15C + 12C using a newly developed active target-detector system (MUSIC). Comparison of the obtained cross sections with theoretical predictions show a good agreement in the energy region accessible with existing radioactive beams. This type of comparison allows us to calibrate the calculations for cases that cannot be studied in the laboratory with the current experimental capabilities. The high efficiency of this active detector system will allow future measurements with even more neutron-rich isotopes. The interaction between exotic nuclei plays an important role for understanding the reaction mechanism of the fusion processes as well as for the energy production in stars. With the advent of radioactive beams new frontiers for fusion reaction studies have become accessible. We have performed the first measurements of the total fusion cross sections in the systems 10 , 14 , 15C + 12C using a newly developed active target-detector system (MUSIC). Comparison of the obtained cross sections with theoretical predictions show a good agreement in the energy region accessible with existing radioactive beams. This type of comparison allows us to calibrate the calculations for cases that cannot be studied in the laboratory with the current experimental capabilities. The high efficiency of this active detector system will allow future measurements with even more neutron-rich isotopes. This work is supported by the U.S. DOE Office of Nuclear Physics under Contract No. DE-AC02-06CH11357 and the Universidad Nacional de San Martin, Argentina, Grant SJ10/39.

The Equilibrium and Pre-equilibrium Triton Emission Spectra of Some Target Nuclei for ( n, xt) Reactions up to 45 MeV Energy

NASA Astrophysics Data System (ADS)

Tel, E.; Kaplan, A.; Aydın, A.; Özkorucuklu, S.; Büyükuslu, H.; Yıldırım, G.

2010-08-01

Although there have been significant research and development studies on the inertial and magnetic fusion reactor technology, there is still a long way to go to penetrate commercial fusion reactors to the energy market. Tritium self-sufficiency must be maintained for a commercial power plant. For self-sustaining (D-T) fusion driver tritium breeding ratio should be greater than 1.05. So, working out the systematics of ( n,t) reaction cross sections and triton emission differential data are important for the given reaction taking place on various nuclei at different energies. In this study, ( n,xt) reactions for some target nuclei as 16O, 27Al, 59Co and 209Bi have been investigated up to 45 MeV incident neutron energy. In the calculations of the triton emission spectra, the pre-equilibrium and equilibrium effects have been used. The calculated results have been compared with the experimental data taken from the literature.

Role of Mediator and Effects of Temperature on ortho-C-N Bond Fusion Reactions of Aniline Using Ruthenium Templates: Isolation and Characterization of New Ruthenium Complexes of the in-Situ-Generated Ligands.

PubMed

Roy, Suman K; Sengupta, Debabrata; Rath, Santi Prasad; Saha, Tanushri; Samanta, Subhas; Goswami, Sreebrata

2017-05-01

In this work, ortho-C-N bond fusion reactions of aniline are followed by the use of two different ruthenium mediators. Reaction of aniline with [Ru III (terpy)Cl 3 ] (terpy = 2,2':6',2″-terpyridine) resulted in a trans bis-aniline ruthenium(II) complex [1] + which upon oxidation with H 2 O 2 produced compound [2] + of a bidentate ligand, N-phenyl-1,2-benzoquinonediimine, due to an oxidative ortho-C-N bond fusion reaction. Complex [1] + and aniline (neat) at 185 °C produced a bis-chelated ruthenium complex (3). A previously reported complex [Ru II (N-phenyl-1,2-benzoquinonediimine)(aniline) 2 (Cl) 2 ] (5) undergoes similar oxidation by air at 185 °C to produce complex [3]. A separate chemical reaction between aniline and strongly oxidizing tetra-n-propylammonium perruthenate [(n-pr) 4 N] + [RuO 4 ] - in air produced a ruthenium complex [4] of a N 4 -tetraamidophenylmacrocycle ligand via multiple ortho-C-N bond fusion reaction. Notably, the yield of this product is low (5%) at 100 °C but increases to 25% in refluxing aniline. All these complexes are characterized fully by their physicochemical characterizations and X-ray structure determination. From their structural parameters and other spectroscopic studies, complex [2] + is assigned as [Ru II (terpy)(N-phenyl-1,2-benzoquinonediimine)(Cl)] + whereas complex [4] is described as a ruthenium(VI) complex comprised of a reduced deprotonated N-phenyl-1,2-diamidobenzene and N 4 -tetraamidophenylmacrocyclic ligand. Complex [2] + exhibits one reversible oxidation at 1.32 V and one reversible reduction at -0.75 V vs Ag/AgCl reference electrode. EPR of the electrogenerated complexes has revealed that the oxidized complex is a ruthenium(III) complex with an axial EPR spectrum at g av = 2.06. The reduced complex [2], on the other hand, shows a single-line EPR signal at g av = 1.998. In contrast, complex [4] shows two successive one-electron oxidation waves at 0.5 and 0.8 V and an irreversible reduction wave at -0.9 V. EPR studies of the oxidized complexes [4] + and [4] 2+ reveal that oxidations are ligand centered. DFT calculations were employed to elucidate the electronic structures as well as the redox processes associated with the above complexes. Aerial ortho-C-N bond fusion reactions of aniline using two different mediators, viz. [Ru III (terpy)Cl 3 ] and [(n-pr) 4 N] + [RuO 4 ] - , have been followed. It is found that in the case of oxidizable Ru(III) mediator complex, C-N bond fusion is limited only to dimerization reaction whereas the high-valent Ru(VII) salt mediates multiple C-N bond fusion reactions leading to the formation of a novel tetradentate N 4 -tetraamidophenylmacrocyclic ligand. Valence ambiguity in the complexes of the resultant redox-active ligands is scrutinized.

Noncompound nucleus decay contribution in the 12C+93Nb reaction using various formulations of nuclear proximity potential

NASA Astrophysics Data System (ADS)

Chopra, Sahila; Kaur, Arshdeep; Gupta, Raj K.

2015-01-01

The earlier study of excitation functions of *105Ag, formed in the 12C+93Nb reaction, based on the dynamical cluster-decay model (DCM), using the pocket formula for nuclear proximity potential is extended to the use of other nuclear interaction potentials derived from the Skyrme energy density functional (SEDF) based on the semiclassical extended Thomas Fermi (ETF) approach and to the use of the extended-Wong model of Gupta and collaborators. The Skyrme forces used are the old SIII and SIV and the new SSk, GSkI, and KDE0(v1) given for both normal and isospin-rich nuclei, with densities added in the frozen-density approximation. Taking advantage of the fact that different Skyrme forces provide different barrier characteristics, we look for the "barrier modification" effects in terms of choosing an appropriate force and hence for the existence or nonexistence of noncompound nucleus (nCN) effects in this reaction. Interestingly, independent of the choice of Skyrme or proximity force, the extended-Wong model fits the experimental data nicely, without any barrier modification and hence no nCN component in the measured fusion cross section, which consists of light-particle evaporation residue (ER) and intermediate-mass fragments (IMFs) up to mass 13, i.e., σfusionExpt .=σER+σIMFs . However, the predicted fusion cross section due to the extended-Wong model is much larger, possibly because of the so-far missing fusion-fission (ff) component in the data. On the other hand, in agreement with the earlier work using the pocket proximity potential, the DCM fits only some data (mainly IMFs) for only some Skyrme forces, and hence it presents the chosen reaction as a case of a large nCN component, whose empirically estimated content is fitted for use of the DCM with a fragment preformation factor taken equal to one, i.e., using DCM (P0=1 ), by introducing "barrier modification" through changing the neck-length parameter Δ R for a best fit to the empirical nCN data in each (ER and IMF) decay channel. Also, the ff component of the DCM is predicted to lie around the symmetric mass A /2 ±16 . All calculations are made for deformed and oriented coplanar nuclei.

The status of cold fusion

NASA Astrophysics Data System (ADS)

Storms, E.

This report attempts to update the status of the phenomenon of cold fusion. The new field is continuing to grow as a variety of nuclear reactions are discovered to occur in a variety of chemical environments at modest temperatures. However, it must be cautioned that most scientists consider cold fusion as something akin to UFO's, ESP, and numerology.

Fusion Ash Separation in the Princeton Field-Reversed Configuration Reactor

NASA Astrophysics Data System (ADS)

Abbate, Joseph; Yeh, Meagan; McGreivy, Nick; Cohen, Samuel

2016-10-01

The Princeton Field-Reversed Configuration (PFRC) concept relies on low-neutron production by D-3He fusion to enable small, safe nuclear-fusion reactors to be built, an approach requiring rapid and efficient extraction of fusion ash and energy produced by D-3He fusion reactions. The ash exhaust stream would contain energetic (0.1-1 MeV) protons, T, 3He, and 4He ions and nearly 1e5 cooler (ca. 100 eV) D ions. The T extracted from the reactor would be a valuable fusion product in that it decays into 3He, which could be used as fuel. If the T were not extracted it would be troublesome because of neutron production by the D-T reaction. This paper discusses methods to separate the various species in a PFRC reactor's exhaust stream. First, we discuss the use of curved magnetic fields to separate the energetic from the cool components. Then we discuss exploiting material properties, specifically reflection, sputtering threshold, and permeability, to allow separation of the hydrogen from the helium isotopes. DOE Contract Number DE-AC02-09CH11466.

A direct fusion drive for rocket propulsion

NASA Astrophysics Data System (ADS)

Razin, Yosef S.; Pajer, Gary; Breton, Mary; Ham, Eric; Mueller, Joseph; Paluszek, Michael; Glasser, Alan H.; Cohen, Samuel A.

2014-12-01

The Direct Fusion Drive (DFD), a compact, anuetronic fusion engine, will enable more challenging exploration missions in the solar system. The engine proposed here uses a deuterium-helium-3 reaction to produce fusion energy by employing a novel field-reversed configuration (FRC) for magnetic confinement. The FRC has a simple linear solenoid coil geometry yet generates higher plasma pressure, hence higher fusion power density, for a given magnetic field strength than other magnetic-confinement plasma devices. Waste heat generated from the plasma's Bremsstrahlung and synchrotron radiation is recycled to maintain the fusion temperature. The charged reaction products, augmented by additional propellant, are exhausted through a magnetic nozzle. A 1 MW DFD is presented in the context of a mission to deploy the James Webb Space Telescope (6200 kg) from GPS orbit to a Sun-Earth L2 halo orbit in 37 days using just 353 kg of propellant and about half a kilogram of 3He. The engine is designed to produce 40 N of thrust with an exhaust velocity of 56.5 km/s and has a specific power of 0.18 kW/kg.

The role of tensor force in heavy-ion fusion dynamics

NASA Astrophysics Data System (ADS)

Guo, Lu; Simenel, Cédric; Shi, Long; Yu, Chong

2018-07-01

The tensor force is implemented into the time-dependent Hartree-Fock (TDHF) theory so that both exotic and stable collision partners, as well as their dynamics in heavy-ion fusion, can be described microscopically. The role of tensor force on fusion dynamics is systematically investigated for 40Ca +40Ca , 40Ca +48Ca , 48Ca +48Ca , 48Ca +56Ni , and 56Ni +56Ni reactions which vary by the total number of spin-unsaturated magic numbers in target and projectile. A notable effect on fusion barriers and cross sections is observed by the inclusion of tensor force. The origin of this effect is analyzed. The influence of isoscalar and isovector tensor terms is investigated with the TIJ forces. These effects of tensor force in fusion dynamics are essentially attributed to the shift of low-lying vibration states of colliding partners and nucleon transfer in the asymmetric reactions. Our calculations of above-barrier fusion cross sections also show that tensor force does not significantly affect the dynamical dissipation at near-barrier energies.

Neutrophil-generated HOCl leads to non-specific thiol oxidation in phagocytized bacteria

PubMed Central

Degrossoli, Adriana; Müller, Alexandra; Xie, Kaibo; Schneider, Jannis F; Bader, Verian; Winklhofer, Konstanze F; Meyer, Andreas J

2018-01-01

Phagocytic immune cells kill pathogens in the phagolysosomal compartment with a cocktail of antimicrobial agents. Chief among them are reactive species produced in the so-called oxidative burst. Here, we show that bacteria exposed to a neutrophil-like cell line experience a rapid and massive oxidation of cytosolic thiols. Using roGFP2-based fusion probes, we could show that this massive breakdown of the thiol redox homeostasis was dependent on phagocytosis, presence of NADPH oxidase and ultimately myeloperoxidase. Interestingly, the redox-mediated fluorescence change in bacteria expressing a glutathione-specific Grx1-roGFP2 fusion protein or an unfused roGFP2 showed highly similar reaction kinetics to the ones observed with roGFP2-Orp1, under all conditions tested. We recently observed such an indiscriminate oxidation of roGFP2-based fusion probes by HOCl with fast kinetics in vitro. In line with these observations, abating HOCl production in immune cells with a myeloperoxidase inhibitor significantly attenuated the oxidation of all three probes in bacteria. PMID:29506649

Direct and compound reactions induced by unstable helium beams near the Coulomb barrier

DOE Office of Scientific and Technical Information (OSTI.GOV)

Navin, A.; Tripathi, V.; Chatterjee, A.

2004-10-01

Reactions induced by radioactive {sup 6,8}He beams from the SPIRAL facility were studied on {sup 63,65}Cu and {sup 188,190,192}Os targets and compared to reactions with the stable {sup 4}He projectiles from the Mumbai Pelletron. Partial residue cross sections for fusion and neutron transfer obtained from the measured intensities of characteristic in-beam {gamma} rays for the {sup 6}He+{sup 63,65}Cu systems are presented. Coincidence measurements of heavy reaction products, identified by their characteristic {gamma} rays, with projectilelike charged particles, provide direct evidence for a large transfer cross section with Borromean nuclei {sup 6}He at 19.5 and 30 MeV and {sup 8}He atmore » 27 MeV. Reaction cross sections were also obtained from measured elastic angular distributions for {sup 6,8}He+Cu systems. Cross sections for fusion and direct reactions with {sup 4,6}He beams on heavier targets of {sup 188,192}Os at 30 MeV are also presented. The present work underlines the need to distinguish between various reaction mechanisms leading to the same products before drawing conclusions about the effect of weak binding on the fusion process. The feasibility of extracting small cross sections from inclusive in-beam {gamma}-ray measurements for reaction studies near the Coulomb barrier with low intensity isotope separation on-line beams is highlighted.« less

Position-sensitive coincidence detection of nuclear reaction products at the Prague Van-de-Graaff accelerator

NASA Astrophysics Data System (ADS)

Granja, Carlos; Kraus, Vaclav; Pugatch, Valery; Kohout, Zdenek

2017-06-01

In low-energy nuclear reactions of astrophysical interest or fusion studies the spatial- and time-correlated detection of two and more reaction products can be a valuable tool in studies of reaction mechanisms, resolving reaction channels and measuring angular distributions of reaction products. For this purpose we constructed a configurable array of position-sensitive detectors based on the hybrid semiconductor pixel detector Timepix. Additional analog-signal electronics provide self-trigger together with extended multi-device control and synchronized readout electronics by a customized control and coincidence unit. The instrumentation, developed and used for detection of fission fragments in spontaneous and neutron induced fission as well as in charged particle detection in neutron induced reactions, is being implemented for low-energy light-ion induced nuclear reactions. Application and demonstration of the technique with two Timepix detectors on p+p elastic scattering at the Van-de-Graaff (VdG) accelerator in Prague is given.

Pionic Fusion of 4He +12 C

NASA Astrophysics Data System (ADS)

Zarrella, Andrew; Yennello, Sherry

2017-09-01

Pionic fusion is the process by which two nuclei fuse and then deexcite by the exclusive emission of a pion. These reactions represent the most extreme examples of deep subthreshold pion production and provide evidence for an unknown, collective mechanism for pion production. An experiment was performed at the Texas A&M University Cyclotron Institute to measure the cross section of the 4He +12 C -> 16N +π+ reaction. The Momentum Achromat Recoil Spectrometer (MARS) was used to separate and identify the 16N fusion residues and the newly constructed Partial Truncated Icosahedron (ParTI) phoswich array was used to identify charged pions. The detector responses for each phoswich unit were recorded using fast-sampling ADCs which allow all light charged particles in the ParTI phoswiches to be identified using ``fast vs. slow'' pulse shape discrimination. By writing the waveform responses, pions can also be identified by the presence of a characteristic muon decay pulse. The combination of the residue-pion coincidence and the two independent pion identification techniques represent a highly sensitive experimental design for studying pionic fusion reactions.

Odd-Z Transactinide Compound Nucleus Reactions Including the Discovery of 260Bh

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nelson, Sarah L.

Several reactions producing odd-Z transactinide compound nuclei were studiedwith the 88-Inch Cyclotron and the Berkeley Gas-Filled Separator at the Lawrence Berkeley National Laboratory. The goal was to produce the same compound nucleus ator near the same excitation energy with similar values of angular momentum via differentnuclear reactions. In doing so, it can be determined if there is a preference in entrancechannel, because under these experimental conditions the survival portion of Swiatecki, Siwek-Wilcznska, and Wilczynski's"Fusion By Diffusion" model is nearly identical forthe two reactions. Additionally, because the same compound nucleus is produced, theexit channel is the same. Four compound nuclei were examined in this study: 258Db, 262Bh, 266Mt, and 272Rg. These nuclei were produced by using very similar heavy-ion induced-fusion reactions which differ only by one proton in the projectile or target nucleus (e.g.: 50Ti + 209Bi vs. 51V + 208Pb). Peak 1n exit channel cross sections were determined for each reaction in each pair, and three of the four pairs' cross sections were identical within statistical uncertainties. This indicates there is not an obvious preference of entrancechannel in these paired reactions. Charge equilibration immediately prior to fusionleading to a decreased fusion barrier is the likely cause of this phenomenon. In addition to this systematic study, the lightest isotope of element 107, bohrium, was discovered in the 209Bi( 52Cr,n) reaction. 260Bh was found to decay by emission of a 10.16 MeV alpha particle with a half-life of 35more » $$+19\\atop{-9}$$ ms. The cross section is 59 pb at an excitation energy of 15.0 MeV. The effect of the N = 152 shell is also seen in this isotope's alpha particle energy, the first evidence of such an effect in Bh. All reactions studied are also compared to model predictions by Swiatecki, Siwek-Wilcznska, and Wilczynski 's" Fusion By Diffusion " theory.« less

PLATYPUS: A code for reaction dynamics of weakly-bound nuclei at near-barrier energies within a classical dynamical model

NASA Astrophysics Data System (ADS)

Diaz-Torres, Alexis

2011-04-01

A self-contained Fortran-90 program based on a three-dimensional classical dynamical reaction model with stochastic breakup is presented, which is a useful tool for quantifying complete and incomplete fusion, and breakup in reactions induced by weakly-bound two-body projectiles near the Coulomb barrier. The code calculates (i) integrated complete and incomplete fusion cross sections and their angular momentum distribution, (ii) the excitation energy distribution of the primary incomplete-fusion products, (iii) the asymptotic angular distribution of the incomplete-fusion products and the surviving breakup fragments, and (iv) breakup observables, such as angle, kinetic energy and relative energy distributions. Program summaryProgram title: PLATYPUS Catalogue identifier: AEIG_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEIG_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 332 342 No. of bytes in distributed program, including test data, etc.: 344 124 Distribution format: tar.gz Programming language: Fortran-90 Computer: Any Unix/Linux workstation or PC with a Fortran-90 compiler Operating system: Linux or Unix RAM: 10 MB Classification: 16.9, 17.7, 17.8, 17.11 Nature of problem: The program calculates a wide range of observables in reactions induced by weakly-bound two-body nuclei near the Coulomb barrier. These include integrated complete and incomplete fusion cross sections and their spin distribution, as well as breakup observables (e.g. the angle, kinetic energy, and relative energy distributions of the fragments). Solution method: All the observables are calculated using a three-dimensional classical dynamical model combined with the Monte Carlo sampling of probability-density distributions. See Refs. [1,2] for further details. Restrictions: The program is suited for a weakly-bound two-body projectile colliding with a stable target. The initial orientation of the segment joining the two breakup fragments is considered to be isotropic. Additional comments: Several source routines from Numerical Recipies, and the Mersenne Twister random number generator package are included to enable independent compilation. Running time: About 75 minutes for input provided, using a PC with 1.5 GHz processor.

Fusion gamma diagnostics

NASA Astrophysics Data System (ADS)

Medley, S. S.; Cecil, F. E.; Cole, D.; Conway, M. A.; Wilkinson, F. J., III

1985-05-01

Nuclear reactions of interest in fusion research often possess a branch yielding prompt emission of gamma radiation in excess of 15 MeV which can be exploited to provide a new fusion reaction diagnostic having applications similar to conventional neutron emission measurements. Conceptual aspects of fusion gamma diagnostics are discussed with emphasis on application to the Tokamak Fusion Test Reactor (TFTR) during deuterium neutral beam heating of D-T and D-3He plasmas. Recent measurements of the D (T, γ)5He, D(3He, γ)5Li, and D(D, γ)4He branching ratios at low center-of-mass energy (30-100 keV) and of the response of a large volume Ne226 detector for gamma detection in high neutron backgrounds are presented. Using a well-shielded Ne226 detector during 20 MW-120 kV deuterium beam heating of a tritium plasma in TFTR, the D(T, γ)5He gamma signal level is estimated to be 3.5×105 cps.

Double differential light charged particle emission cross sections for some structural fusion materials

NASA Astrophysics Data System (ADS)

Sarpün, Ismail Hakki; n, Abdullah Aydı; Tel, Eyyup

2017-09-01

In fusion reactors, neutron induced radioactivity strongly depends on the irradiated material. So, a proper selection of structural materials will have been limited the radioactive inventory in a fusion reactor. First-wall and blanket components have high radioactivity concentration due to being the most flux-exposed structures. The main objective of fusion structural material research is the development and selection of materials for reactor components with good thermo-mechanical and physical properties, coupled with low-activation characteristics. Double differential light charged particle emission cross section, which is a fundamental data to determine nuclear heating and material damages in structural fusion material research, for some elements target nuclei have been calculated by the TALYS 1.8 nuclear reaction code at 14-15 MeV neutron incident energy and compared with available experimental data in EXFOR library. Direct, compound and pre-equilibrium reaction contribution have been theoretically calculated and dominant contribution have been determined for each emission of proton, deuteron and alpha particle.

A new look at low-energy nuclear reaction research.

PubMed

Krivit, Steven B; Marwan, Jan

2009-10-01

This paper presents a new look at low-energy nuclear reaction research, a field that has developed from one of the most controversial subjects in science, "cold fusion." Early in the history of this controversy, beginning in 1989, a strong polarity existed; many scientists fiercely defended the claim of new physical effects as well as a new process in which like-charged atomic nuclei overcome the Coulomb barrier at normal temperatures and pressures. Many other scientists considered the entire collection of physical observations-along with the hypothesis of a "cold fusion"--entirely a mistake. Twenty years later, some people who had dismissed the field in its entirety are considering the validity of at least some of the reported experimental phenomena. As well, some researchers in the field are wondering whether the underlying phenomena may be not a fusion process but a neutron capture/absorption process. In 2002, a related tabletop form of thermonuclear fusion was discovered in the field of acoustic inertial confinement fusion. We briefly review some of this work, as well.

Interplay of charge clustering and weak binding in reactions of 8Li

NASA Astrophysics Data System (ADS)

Cook, K. J.; Carter, I. P.; Simpson, E. C.; Dasgupta, M.; Hinde, D. J.; Bezzina, L. T.; Kalkal, Sunil; Sengupta, C.; Simenel, C.; Swinton-Bland, B. M. A.; Vo-Phuoc, K.; Williams, E.

2018-02-01

In collisions of light, stable, weakly bound nuclides, complete fusion (capture of all of the projectile charge) has been found to be suppressed by ˜30 % at above-barrier energies. This is thought to be related to their low thresholds for breakup into charged clusters. The observation of fusion suppression in the neutron-rich radioactive nucleus 8Li is therefore puzzling: the lowest breakup threshold yields 7Li+n which cannot contribute to fusion suppression because 7Li retains all the projectile charge. In this work, the full characteristics of 8Li breakup in reactions with 209Bi are presented, including, for the first time, coincidence measurements of breakup into charged clusters. Correlations of cluster fragments show that most breakup occurs too slowly to significantly suppress fusion. However, a large cross section for unaccompanied α particles was found, suggesting that charge clustering, facilitating partial charge capture, rather than weak binding is the crucial factor in fusion suppression, which may therefore persist in exotic nuclides.

Toroidal reactor

DOEpatents

Dawson, John M.; Furth, Harold P.; Tenney, Fred H.

1988-12-06

Method for producing fusion power wherein a neutral beam is injected into a toroidal bulk plasma to produce fusion reactions during the time permitted by the slowing down of the particles from the injected beam in the bulk plasma.

Possibilities of production of transfermium nuclei in charged-particle evaporation channels

NASA Astrophysics Data System (ADS)

Hong, Juhee; Adamian, G. G.; Antonenko, N. V.

2016-10-01

The possibilities of direct production of the isotopes of transfermium nuclei Md,260259, No,261260, Lr-264261, Rf,265264, Db-268264, Sg-269266, Bh-271266, Hs-274267, and Mt-274270 in various asymmetric hot fusion-evaporation reactions are studied. The excitation functions of the formation of these isotopes in the α x n and p x n evaporation channels are predicted for the first time. The optimal reaction partners and conditions for the synthesis of new isotopes are suggested. The products of the suggested reactions can fill a gap of unknown isotopes between the isotopes of heaviest nuclei obtained in the x n evaporation channels of the cold and hot complete fusion reactions.

Reaction rate for carbon burning in massive stars

NASA Astrophysics Data System (ADS)

Jiang, C. L.; Santiago-Gonzalez, D.; Almaraz-Calderon, S.; Rehm, K. E.; Back, B. B.; Auranen, K.; Avila, M. L.; Ayangeakaa, A. D.; Bottoni, S.; Carpenter, M. P.; Dickerson, C.; DiGiovine, B.; Greene, J. P.; Hoffman, C. R.; Janssens, R. V. F.; Kay, B. P.; Kuvin, S. A.; Lauritsen, T.; Pardo, R. C.; Sethi, J.; Seweryniak, D.; Talwar, R.; Ugalde, C.; Zhu, S.; Bourgin, D.; Courtin, S.; Haas, F.; Heine, M.; Fruet, G.; Montanari, D.; Jenkins, D. G.; Morris, L.; Lefebvre-Schuhl, A.; Alcorta, M.; Fang, X.; Tang, X. D.; Bucher, B.; Deibel, C. M.; Marley, S. T.

2018-01-01

Carbon burning is a critical phase for nucleosynthesis in massive stars. The conditions for igniting this burning stage, and the subsequent isotope composition of the resulting ashes, depend strongly on the reaction rate for 12C+12C fusion at very low energies. Results for the cross sections for this reaction are influenced by various backgrounds encountered in measurements at such energies. In this paper, we report on a new measurement of 12C+12C fusion cross sections where these backgrounds have been minimized. It is found that the astrophysical S factor exhibits a maximum around Ecm=3.5 -4.0 MeV, which leads to a reduction of the previously predicted astrophysical reaction rate.

Study of Heavy-ion Induced Fission for Heavy Element Synthesis

NASA Astrophysics Data System (ADS)

Nishio, K.; Ikezoe, H.; Hofmann, S.; Ackermann, D.; Aritomo, Y.; Comas, V. F.; Düllmann, Ch. E.; Heinz, S.; Heredia, J. A.; Heßberger, F. P.; Hirose, K.; Khuyagbaatar, J.; Kindler, B.; Kojouharov, I.; Lommel, B.; Makii, M.; Mann, R.; Mitsuoka, S.; Nishinaka, I.; Ohtsuki, T.; Saro, S.; Schädel, M.; Popeko, A. G.; Türler, A.; Wakabayashi, Y.; Watanabe, Y.; Yakushev, A.; Yeremin, A.

2014-05-01

Fission fragment mass distributions were measured in heavy-ion induced fission of 238U. The mass distributions changed drastically with incident energy. The results are explained by a change of the ratio between fusion and quasifission with nuclear orientation. A calculation based on a fluctuation dissipation model reproduced the mass distributions and their incident energy dependence. Fusion probability was determined in the analysis. Evaporation residue cross sections were calculated with a statistical model for the reactions of 30Si+238U and 34S+238U using the obtained fusion probability in the entrance channel. The results agree with the measured cross sections of 263,264Sg and 267,268Hs, produced by 30Si+238U and 34S+238U, respectively. It is also suggested that sub-barrier energies can be used for heavy element synthesis.

Fusion Reactions and Matter-Antimatter Annihilation for Space Propulsion

DTIC Science & Technology

2005-07-13

shielding. λ D-3He eliminates the need for a complicated tritium-breeding blanked and tritium-processing system. 4 - MAGNETIC FUSION ENERGY (MFE...resulting specific powers. 5 - INERTIAL FUSION ENERGY (IFE) The possibility of igniting thermonuclear micro-explosions with pulsed laser beams was... fusion energy to antimatter rest mass energy, β, of 1.6 × 107. However, energy utilization is also lower due to the isotropic expansion process (ηe ~ 15

Unified ab initio approaches to nuclear structure and reactions

DOE PAGES

Navratil, Petr; Quaglioni, Sofia; Hupin, Guillaume; ...

2016-04-13

The description of nuclei starting from the constituent nucleons and the realistic interactions among them has been a long-standing goal in nuclear physics. In addition to the complex nature of the nuclear forces, with two-, three- and possibly higher many-nucleon components, one faces the quantum-mechanical many-nucleon problem governed by an interplay between bound and continuum states. In recent years, significant progress has been made in ab initio nuclear structure and reaction calculations based on input from QCD-employing Hamiltonians constructed within chiral effective field theory. After a brief overview of the field, we focus on ab initio many-body approaches—built upon the no-core shell model—that are capable of simultaneously describing both bound and scattering nuclear states, and present results for resonances in light nuclei, reactions important for astrophysics and fusion research. In particular, we review recent calculations of resonances in the 6He halo nucleus, of five- and six-nucleon scattering, and an investigation of the role of chiral three-nucleon interactions in the structure of 9Be. Further, we discuss applications to the 7Bemore » $${({\\rm{p}},\\gamma )}^{8}{\\rm{B}}$$ radiative capture. Lastly, we highlight our efforts to describe transfer reactions including the 3H$${({\\rm{d}},{\\rm{n}})}^{4}$$He fusion.« less

Efficient neutron generation from solid-nanoparticle explosions driven by DPSSL-pumped high-repetition rate femtosecond laser pulse

NASA Astrophysics Data System (ADS)

Watari, T.; Matsukado, K.; Sekine, T.; Takeuchi, Y.; Hatano, Y.; Yoshimura, R.; Satoh, N.; Nishihara, K.; Takagi, M.; Kawashima, T.

2016-03-01

We propose novel neutron source using high-intensity laser based on the cluster fusion scheme. We developed DPSSL-pumped high-repetition-rate 20-TW laser system and solid nanoparticle target for neutron generation demonstration. In our neutron generation experiment, high-energy deuterons were generated from coulomb explosion of CD solid- nanoparticles and neutrons were generated by DD fusion reaction. Efficient and stable neutron generation was obtained by irradiating an intense femtosecond laser pulse of >2×1018 W/cm2. A yield of ∼105 neutrons per shot was stably observed during 0.1-1 Hz continuous operation.

A sensitive and high throughput TaqMan-based reverse transcription quantitative polymerase chain reaction assay efficiently discriminates ALK rearrangement from overexpression for lung cancer FFPE specimens.

PubMed

Lung, Jrhau; Lin, Yu-Ching; Hung, Ming-Szu; Jiang, Yuan Yuan; Lee, Kuan-Der; Lin, Paul Yann; Tsai, Ying Huang

2016-04-01

ALK fusion gene is an oncogenic driver in lung cancer with low prevalence, which can be ameliorated by crizotinib. Currently, ALK fusion gene can be diagnosed by fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC), but inconstistnt results between the two methods are encountered regularly. To make the ALK fusion gene screening more efficient and to provide a simple solution to clarify the discrepancy between FISH and IHC results, a sensitive TaqMan-based reverse transcription quantitative polymerase chain reaction (RT-qPCR) assay was established. The 3-plex TaqMan-based RT-qPCR assay was established and performed on 102 archived formalin-fixed, paraffin-embedded (FFPE) NSCLC samples to detect ALK rearrangement and overexpression. Break-apart FISH and automatic immunohistochemistry based ALK assays were performed side by side using tissue microarray. The RT-qPCR was performed successfully for 80 samples and 10 of them showed positive signals. Three out of the 10 qPCR positive cases were further confirmed by FISH and IHC test. Two others were IHC positive and FISH negative, and expressed full-length ALK transcript. The rest were neither FISH nor IHC positive and their ALK expression level was significantly lower than those FISH or IHC positive cases. Our RT-qPCR assay demonstrates that the capability and reliability of ALK detection is comparable to FISH and IHC, but it is more effective at discriminating ALK rearrangement from overexpression. The RT-qPCR assay easily clarifies the discrepancy between FISH and IHC, and can be incorporated into routine ALK screening for lung cancer. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Fusion-fission and quasifission of superheavy systems with Z =110 -116 formed in 48Ca-induced reactions

NASA Astrophysics Data System (ADS)

Kozulin, E. M.; Knyazheva, G. N.; Itkis, I. M.; Itkis, M. G.; Bogachev, A. A.; Chernysheva, E. V.; Krupa, L.; Hanappe, F.; Dorvaux, O.; Stuttgé, L.; Trzaska, W. H.; Schmitt, C.; Chubarian, G.

2014-11-01

Background: In heavy-ion-induced reactions the mechanism leading to the formation of the compound nucleus and the role of quasifission is still not clear. Purpose: Investigation of the quasifission process of superheavy composite systems with Z =110 -116 and comparison with properties of fusion-fission and quasifission of lighter composite systems. Method: Mass and energy distributions of fissionlike fragments formed in the reactions 48Ca+232Th, 238U , 244Pu , and 248Cm at energies near the Coulomb barrier have been measured using the double-arm time-of-flight spectrometer CORSET at the U-400 cyclotron of the FLNR JINR. Results: The most probable fragment masses as well as total kinetic energies and their dispersions in dependence on the interaction energies and ion-target combinations have been studied for asymmetric and symmetric fragments formed in the reactions. The capture cross sections were obtained for the reactions 48Ca+244Pu and 248Cm . The lower limits for fission barriers of 283 -286Cn , 289 -292Fl , and 293 -296Lv compound nuclei were estimated. Conclusions: Analysis of the properties of symmetric fragments has shown that a significant part of these fragments may be attributed to fusion-fission process for the reactions 48Ca +238U , 244Pu , and 248Cm .

User Evaluation of Automatically Generated Semantic Hypertext Links in a Heavily Used Procedural Manual.

ERIC Educational Resources Information Center

Tebbutt, John

1999-01-01

Discusses efforts at National Institute of Standards and Technology (NIST) to construct an information discovery tool through the fusion of hypertext and information retrieval that works by parsing a contiguous document base into smaller documents and inserting semantic links between them. Also presents a case study that evaluated user reactions.…

Characterization of the functional requirements of West Nile virus membrane fusion.

PubMed

Moesker, Bastiaan; Rodenhuis-Zybert, Izabela A; Meijerhof, Tjarko; Wilschut, Jan; Smit, Jolanda M

2010-02-01

Flaviviruses infect their host cells by a membrane fusion reaction. In this study, we performed a functional analysis of the membrane fusion properties of West Nile virus (WNV) with liposomal target membranes. Membrane fusion was monitored continuously using a lipid mixing assay involving the fluorophore, pyrene. Fusion of WNV with liposomes occurred on the timescale of seconds and was strictly dependent on mildly acidic pH. Optimal fusion kinetics were observed at pH 6.3, the threshold for fusion being pH 6.9. Preincubation of the virus alone at pH 6.3 resulted in a rapid loss of fusion capacity. WNV fusion activity is strongly promoted by the presence of cholesterol in the target membrane. Furthermore, we provide direct evidence that cleavage of prM to M is a requirement for fusion activity of WNV.

Dynamics of complete and incomplete fusion in heavy ion collisions

NASA Astrophysics Data System (ADS)

Bao, Xiao Jun; Guo, Shu Qing; Zhang, Hong Fei; Li, Jun Qing

2018-02-01

In order to study the influence of the strong Coulomb and nuclear interactions on the dynamics of complete and incomplete fusion, we construct a new four-variable master equation (ME) so that the deformations as well as the nucleon transfer are viewed as consistently governed by MEs in the potential energy surface of the system. The calculated yields of quasifission fragments and evaporation residue cross section (ERCS) are in agreement with experimental data of hot fusion reactions. Comparing cross sections by theoretical results and experimental data, we find the improved dinuclear sysytem model also describes the transfer cross sections reasonably. The production cross sections of new neutron-rich isotopes are estimated by the multinucleon transfer reactions.

First AC loss test and analysis of a Bi2212 cable-in-conduit conductor for fusion application

NASA Astrophysics Data System (ADS)

Qin, Jinggang; Shi, Yi; Wu, Yu; Li, Jiangang; Wang, Qiuliang; He, Yuxiang; Dai, Chao; Liu, Fang; Liu, Huajun; Mao, Zhehua; Nijhuis, Arend; Zhou, Chao; Devred, Arnaud

2018-01-01

The main goal of the Chinese fusion engineering test reactor (CFETR) is to build a fusion engineering tokamak reactor with a fusion power of 50-200 MW, and plan to test the breeding tritium during the fusion reaction. This may require a maximum magnetic field of the central solenoid and toroidal field coils up to 15 T. New magnet technologies should be developed for the next generation of fusion reactors with higher requirements. Bi2Sr2CaCu2Ox (Bi2212) is considered as a potential and promising superconductor for the magnets in the CFETR. R&D activities are ongoing at the Institute of Plasma Physics, Chinese Academy of Sciences for demonstration of the feasibility of a CICC based on Bi2212 round wire. One sub-size conductor cabled with 42 wires was designed, manufactured and tested with limited strand indentation during cabling and good transport performance. In this paper, the first test results and analysis on the AC loss of Bi2212 round wires and cabled conductor samples are presented. Furthermore, the impact of mechanical load on the AC loss of the sub-size conductor is investigated to represent the operation conditions with electromagnetic loads. The first tests provide an essential basis for the validation of Bi2212 CICC and its application in fusion magnets.

Simultaneous usage of pinhole and penumbral apertures for imaging small scale neutron sources from inertial confinement fusion experiments.

PubMed

Guler, N; Volegov, P; Danly, C R; Grim, G P; Merrill, F E; Wilde, C H

2012-10-01

Inertial confinement fusion experiments at the National Ignition Facility are designed to understand the basic principles of creating self-sustaining fusion reactions by laser driven compression of deuterium-tritium (DT) filled cryogenic plastic capsules. The neutron imaging diagnostic provides information on the distribution of the central fusion reaction region and the surrounding DT fuel by observing neutron images in two different energy bands for primary (13-17 MeV) and down-scattered (6-12 MeV) neutrons. From this, the final shape and size of the compressed capsule can be estimated and the symmetry of the compression can be inferred. These experiments provide small sources with high yield neutron flux. An aperture design that includes an array of pinholes and penumbral apertures has provided the opportunity to image the same source with two different techniques. This allows for an evaluation of these different aperture designs and reconstruction algorithms.

Modelling third harmonic ion cyclotron acceleration of deuterium beams for JET fusion product studies experiments

NASA Astrophysics Data System (ADS)

Schneider, M.; Johnson, T.; Dumont, R.; Eriksson, J.; Eriksson, L.-G.; Giacomelli, L.; Girardo, J.-B.; Hellsten, T.; Khilkevitch, E.; Kiptily, V. G.; Koskela, T.; Mantsinen, M.; Nocente, M.; Salewski, M.; Sharapov, S. E.; Shevelev, A. E.; Contributors, JET

2016-11-01

Recent JET experiments have been dedicated to the studies of fusion reactions between deuterium (D) and Helium-3 (3He) ions using neutral beam injection (NBI) in synergy with third harmonic ion cyclotron radio-frequency heating (ICRH) of the beam. This scenario generates a fast ion deuterium tail enhancing DD and D3He fusion reactions. Modelling and measuring the fast deuterium tail accurately is essential for quantifying the fusion products. This paper presents the modelling of the D distribution function resulting from the NBI+ICRF heating scheme, reinforced by a comparison with dedicated JET fast ion diagnostics, showing an overall good agreement. Finally, a sawtooth activity for these experiments has been observed and interpreted using SPOT/RFOF simulations in the framework of Porcelli’s theoretical model, where NBI+ICRH accelerated ions are found to have a strong stabilizing effect, leading to monster sawteeth.

First downscattered neutron images from Inertial Confinement Fusion experiments at the National Ignition Facility

NASA Astrophysics Data System (ADS)

Guler, Nevzat; Aragonez, Robert J.; Archuleta, Thomas N.; Batha, Steven H.; Clark, David D.; Clark, Deborah J.; Danly, Chris R.; Day, Robert D.; Fatherley, Valerie E.; Finch, Joshua P.; Gallegos, Robert A.; Garcia, Felix P.; Grim, Gary; Hsu, Albert H.; Jaramillo, Steven A.; Loomis, Eric N.; Mares, Danielle; Martinson, Drew D.; Merrill, Frank E.; Morgan, George L.; Munson, Carter; Murphy, Thomas J.; Oertel, John A.; Polk, Paul J.; Schmidt, Derek W.; Tregillis, Ian L.; Valdez, Adelaida C.; Volegov, Petr L.; Wang, Tai-Sen F.; Wilde, Carl H.; Wilke, Mark D.; Wilson, Douglas C.; Atkinson, Dennis P.; Bower, Dan E.; Drury, Owen B.; Dzenitis, John M.; Felker, Brian; Fittinghoff, David N.; Frank, Matthias; Liddick, Sean N.; Moran, Michael J.; Roberson, George P.; Weiss, Paul; Buckles, Robert A.; Cradick, Jerry R.; Kaufman, Morris I.; Lutz, Steve S.; Malone, Robert M.; Traille, Albert

2013-11-01

Inertial Confinement Fusion experiments at the National Ignition Facility (NIF) are designed to understand and test the basic principles of self-sustaining fusion reactions by laser driven compression of deuterium-tritium (DT) filled cryogenic plastic (CH) capsules. The experimental campaign is ongoing to tune the implosions and characterize the burning plasma conditions. Nuclear diagnostics play an important role in measuring the characteristics of these burning plasmas, providing feedback to improve the implosion dynamics. The Neutron Imaging (NI) diagnostic provides information on the distribution of the central fusion reaction region and the surrounding DT fuel by collecting images at two different energy bands for primary (13-15 MeV) and downscattered (10-12 MeV) neutrons. From these distributions, the final shape and size of the compressed capsule can be estimated and the symmetry of the compression can be inferred. The first downscattered neutron images from imploding ICF capsules are shown in this paper.

Tritium Breeding Blanket for a Commercial Fusion Power Plant - A System Engineering Assessment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meier, Wayne R.

The goal of developing a new source of electric power based on fusion has been pursued for decades. If successful, future fusion power plants will help meet growing world-wide demand for electric power. A key feature and selling point for fusion is that its fuel supply is widely distributed globally and virtually inexhaustible. Current world-wide research on fusion energy is focused on the deuterium-tritium (DT for short) fusion reaction since it will be the easiest to achieve in terms of the conditions (e.g., temperature, density and confinement time of the DT fuel) required to produce net energy. Over the pastmore » decades countless studies have examined various concepts for TBBs for both magnetic fusion energy (MFE) and inertial fusion energy (IFE). At this time, the key organizations involved are government sponsored research organizations world-wide. The near-term focus of the MFE community is on the development of TBB mock-ups to be tested on the ITER tokamak currently under construction in Caderache France. TBB concepts for IFE tend to be different from MFE primarily due to significantly different operating conditions and constraints. This report focuses on longer-term commercial power plants where the key stakeholders include: electric utilities, plant owner and operator, manufacturer, regulators, utility customers, and in-plant subsystems including the heat transfer and conversion systems, fuel processing system, plant safety systems, and the monitoring control systems.« less

Temperature derivatives for fusion reactivity of D-D and D-T

DOE Office of Scientific and Technical Information (OSTI.GOV)

Langenbrunner, James R.; Makaruk, Hanna Ewa

Deuterium-tritium (D-T) and deuterium-deuterium (D-D) fusion reaction rates are observable using leakage gamma flux. A direct measurement of γ-rays with equipment that exhibits fast temporal response could be used to infer temperature, if the detector signal is amenable for taking the logarithmic time-derivative, alpha. We consider the temperature dependence for fusion cross section reactivity.

Three-dimensional modeling of the neutron spectrum to infer plasma conditions in cryogenic inertial confinement fusion implosions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weilacher, F.; Radha, P. B.; Forrest, C.

Neutron-based diagnostics are typically used to infer compressed core conditions such as areal density and ion temperature in deuterium–tritium (D–T) inertial confinement fusion (ICF) implosions. Asymmetries in the observed neutron-related quantities are important to understanding failure modes in these implosions. Neutrons from fusion reactions and their subsequent interactions including elastic scattering and neutron-induced deuteron breakup reactions are tracked to create spectra. Here, it is shown that background subtraction is important for inferring areal density from backscattered neutrons and is less important for the forward-scattered neutrons. A three-dimensional hydrodynamic simulation of a cryogenic implosion on the OMEGA Laser System [T. R.more » Boehly et al., Opt. Commun. 133, 495 (1997)] using the hydrodynamic code HYDRA [M. M. Marinak et al., Phys. Plasmas 8, 2275 (2001)] is post-processed using the tracking code IRIS3D. It is shown that different parts of the neutron spectrum from the view can be mapped into different regions of the implosion, enabling an inference of an areal-density map. It is also shown that the average areal-density and an areal-density map of the compressed target can be reconstructed with a finite number of detectors placed around the target chamber. Ion temperatures are inferred from the width of the D–D and D–T fusion neutron spectra. Backgrounds can significantly alter the inferred ion temperatures from the D–D reaction, whereas they insignificantly influence the inferred D–T ion temperatures for the areal densities typical of OMEGA implosions. Asymmetries resulting in fluid flow in the core are shown to influence the absolute inferred ion temperatures from both reactions, although relative inferred values continue to reflect the underlying asymmetry pattern. The work presented here is part of the wide range of the first set of studies performed with IRIS3D. Finally, this code will continue to be used for post-processing detailed hydrodynamic simulations and interpreting observed neutron spectra in ICF implosions.« less

Three-dimensional modeling of the neutron spectrum to infer plasma conditions in cryogenic inertial confinement fusion implosions

DOE PAGES

Weilacher, F.; Radha, P. B.; Forrest, C.

2018-04-26

Neutron-based diagnostics are typically used to infer compressed core conditions such as areal density and ion temperature in deuterium–tritium (D–T) inertial confinement fusion (ICF) implosions. Asymmetries in the observed neutron-related quantities are important to understanding failure modes in these implosions. Neutrons from fusion reactions and their subsequent interactions including elastic scattering and neutron-induced deuteron breakup reactions are tracked to create spectra. Here, it is shown that background subtraction is important for inferring areal density from backscattered neutrons and is less important for the forward-scattered neutrons. A three-dimensional hydrodynamic simulation of a cryogenic implosion on the OMEGA Laser System [T. R.more » Boehly et al., Opt. Commun. 133, 495 (1997)] using the hydrodynamic code HYDRA [M. M. Marinak et al., Phys. Plasmas 8, 2275 (2001)] is post-processed using the tracking code IRIS3D. It is shown that different parts of the neutron spectrum from the view can be mapped into different regions of the implosion, enabling an inference of an areal-density map. It is also shown that the average areal-density and an areal-density map of the compressed target can be reconstructed with a finite number of detectors placed around the target chamber. Ion temperatures are inferred from the width of the D–D and D–T fusion neutron spectra. Backgrounds can significantly alter the inferred ion temperatures from the D–D reaction, whereas they insignificantly influence the inferred D–T ion temperatures for the areal densities typical of OMEGA implosions. Asymmetries resulting in fluid flow in the core are shown to influence the absolute inferred ion temperatures from both reactions, although relative inferred values continue to reflect the underlying asymmetry pattern. The work presented here is part of the wide range of the first set of studies performed with IRIS3D. Finally, this code will continue to be used for post-processing detailed hydrodynamic simulations and interpreting observed neutron spectra in ICF implosions.« less

Chemically ignited thermonuclear reactions—A near-term means for a high specific impulse—High thrust propulsion system

NASA Astrophysics Data System (ADS)

Winterberg, F.

The combination of metallic shells imploded with chemical explosives and the recently proposed magnetic booster target inertial fusion concept, could make possible the fissionless ignition of small thermonuclear explosions. In the magnetic booster concept a very dense but magnetically confined thermonuclear plasma of low yield serves as the trigger for an inertially confined thermonuclear plasma of high yield. For the most easily ignitable fusion reaction, the DT reaction, this could lead to a fissionless bomb propulsion system, with the advantage to have a much smaller yield of the pure fusion bombs as compared to either fission- or fission-induced fusion bombs, previously proposed for propulsion. Typically, the proposed propulsion concept should give a specific impulse of ˜ 3000 secs, corresponding to an exhaust velocity of ˜ 30 km/sec. If the energy released in each pure fusion bomb is of the order of 10 18 erg or the order of 100 tons of TNT, and if one fusion explosion per second takes place, the average thrust is of the order 10 3 tons. The propulsion system appears ideally suited for the fast economical transport of large spacecraft within the solar system.

Fusion of deformed nuclei in the reactions of 76Ge+150Nd and 28Si+198Pt at the Coulomb barrier region

NASA Astrophysics Data System (ADS)

Nishio, K.; Ikezoe, H.; Mitsuoka, S.; Lu, J.

2000-07-01

Evaporation residue cross sections for 28Si+198Pt and 76Ge+150Nd, both of which form a compound nucleus 226U, were measured in the vicinity of the Coulomb barrier. The measurement gives direct evidence that the system really fuses together to form a fully equilibrated compound nucleus. For the 28Si+198Pt reaction, we have measured the fission fragments to determine the fusion cross section by taking advantage of the highly fissile character of 226U. The evaporation residue cross section and the fusion cross section for 28Si+198Pt allowed us to investigate the deexcitation process (exit channel) of the compound nucleus 226U, and the parameters entering in a statistical model calculation could be determined. By estimating the deexcitation of the compound nucleus 226U with the statistical model, the effect of the deformed nucleus 150Nd on the fusion reaction 76Ge+150Nd was extracted. The experimental data indicated that there is more than 13 MeV extra-extra-push energy for the system to fuse together when the projectile 76Ge collides at the tip of the deformed 150Nd nucleus. On the contrary, for the side collision which is more compact in configuration than the tip collision, no fusion hindrance is suggested.

Reaction rate for carbon burning in massive stars

DOE PAGES

Jiang, C. L.; Santiago-Gonzalez, D.; Almaraz-Calderon, S.; ...

2018-01-10

Carbon burning is a critical phase for nucleosynthesis in massive stars. The conditions for igniting this burning stage, and the subsequent isotope composition of the resulting ashes, depend strongly on the reaction rate for 12C+ 12C fusion at very low energies. Results for the cross sections for this reaction are influenced by various backgrounds encountered in measurements at such energies. In this paper, we report on a new measurement of 12C+ 12C fusion cross sections where these backgrounds have been minimized. In conclusion, it is found that the astrophysical S factor exhibits a maximum around E cm=3.5–4.0 MeV, which leadsmore » to a reduction of the previously predicted astrophysical reaction rate.« less

Nuclear Fusion Blast and Electrode Lifetimes in a PJMIF Reactor

NASA Astrophysics Data System (ADS)

Thio, Y. C. Francis; Witherspoon, F. D.; Case, A.; Brockington, S.; Cruz, E.; Luna, M.; Hsu, S. C.

2017-10-01

We present an analysis and numerical simulation of the nuclear blast from the micro-explosion following the completion of the fusion burn for a baseline design of a PJMIF fusion reactor with a fusion gain of 20. The stagnation pressure from the blast against the chamber wall defines the engineering requirement for the structural design of the first wall and the plasma guns. We also present an analysis of the lifetimes of the electrodes of the plasma guns which are exposed to (1) the high current, and (2) the neutron produced by the fusion reactions. We anticipate that the gun electrodes are made of tungsten alloys as plasma facing components reinforced structurally by appropriate steel alloys. Making reasonable assumptions about the electrode erosion rate (100 ng/C transfer), the electrode lifetime limited by the erosion rate is estimated to be between 19 and 24 million pulses before replacement. Based on known neutron radiation effects on structural materials such as steel alloys and plasma facing component materials such as tungsten alloys, the plasma guns are expected to survive some 22 million shots. At 1 Hz, this equal to about 6 months of continuous operation before they need to be replaced. Work supported by Strong Atomics, LLC.

Refined Calculations of Secondary Nuclear Reactions in Magneto-Inertial Fusion Plasmas

NASA Astrophysics Data System (ADS)

Schmit, Paul; Knapp, Patrick; Hansen, Stephanie; Gomez, Matthew; Hahn, Kelly; Sinars, Daniel; Peterson, Kyle; Slutz, Stephen; Sefkow, Adam; Awe, Thomas; Harding, Eric; Jennings, Christopher

2014-10-01

Diagnosing the degree of magnetic flux compression at stagnation in magneto-inertial fusion (MIF) is critical for charting the performance of any MIF concept. In pure deuterium plasma, the transport of high-energy tritons produced by the aneutronic DD fusion reaction depends strongly on the magnetic field. The tritons probe and occasionally react with the fuel, emitting secondary DT neutrons. We show that the DT/DD neutron yield ratio and the secondary DT neutron spectra can be used to infer the magnetic field-radius product (BR), the critical confinement parameter for MIF. The amount of fuel-pusher mix also can be constrained by secondary reactions. We discuss the sensitivity to plasma inhomogeneities of the calculations and outline methods to relate secondary yields to alpha particle energy deposition in ignition-relevant experiments employing DT fuel. We compare our calculations to recent tests of the Magnetized Liner Inertial Fusion (MagLIF) concept on the Z Pulsed Power Facility. Supported in part by the SNL Truman Fellowship, which is part of the LDRD Program, and sponsored by Sandia Corporation (a wholly owned subsidiary of Lockheed Martin Corporation) as Operator of SNL under its U.S. DoE Contract No. DE-AC04-94AL85000.

Avalanche boron fusion by laser picosecond block ignition with magnetic trapping for clean and economic reactor

DOE PAGES

Hora, H.; Korn, G.; Eliezer, S.; ...

2016-10-11

Measured highly elevated gains of proton–boron (HB11) fusion (Picciottoet al., Phys. Rev. X4, 031030 (2014)) confirmed the exceptional avalanche reaction process (Lalousiset al., Laser Part. Beams 32, 409 (2014); Horaet al., Laser Part. Beams33, 607 (2015)) for the combination of the non-thermal block ignition using ultrahigh intensity laser pulses of picoseconds duration. The ultrahigh accelerationabovemore » $$10^{20}~\\text{cm}~\\text{s}^{-2}$$ for plasma blocks was theoretically and numerically predicted since 1978 (Hora,Physics of Laser Driven Plasmas(Wiley, 1981), pp. 178 and 179) and measured (Sauerbrey, Phys. Plasmas3, 4712 (1996)) in exact agreement (Horaet al., Phys. Plasmas14, 072701 (2007)) when the dominating force was overcoming thermal processes. This is based on Maxwell’s stress tensor by the dielectric properties of plasma leading to the nonlinear (ponderomotive) force $$f_{\\text{NL}}$$ resulting in ultra-fast expanding plasma blocks by a dielectric explosion. Combining this with measured ultrahigh magnetic fields and the avalanche process opens an option for an environmentally absolute clean and economic boron fusion power reactor. Finally, this is supported also by other experiments with very high HB11 reactions under different conditions (Labauneet al., Nature Commun.4, 2506 (2013)).« less

Study of breakup and transfer of weakly bound nucleus 6Li to explore the low energy reaction dynamics

NASA Astrophysics Data System (ADS)

Zhang, G. L.; Zhang, G. X.; Hu, S. P.; Zhang, H. Q.; Gomes, P. R. S.; Lubian, J.; Guo, C. L.; Wu, X. G.; Yang, J. C.; Zheng, Y.; Li, C. B.; He, C. Y.; Zhong, J.; Li, G. S.; Yao, Y. J.; Guo, M. F.; Sun, H. B.; Valiente-Dobòn, J. J.; Goasduff, A.; Siciliano, M.; Galtarosa, F.; Francesco, R.; Testov, D.; Mengoni, D.; Bazzacco, D.; John, P. R.; Qu, W. W.; Wang, F.; Zheng, L.; Yu, L.; Chen, Q. M.; Luo, P. W.; Li, H. W.; Wu, Y. H.; Zhou, W. K.; Zhu, B. J.; Li, E. T.; Hao, X.

2017-11-01

Investigation of the breakup and transfer effect of weakly bound nuclei on the fusion process has been an interesting research topic in the past several years. However, owing to the low intensities of the presently available radioactive ion beam (RIB), it is difficult to clearly explore the reaction mechanisms of nuclear systems with unstable nuclei. In comparison with RIB, the beam intensities of stable weakly bound nuclei such as 6,7Li and 9Be, which have significant breakup probability, are orders of magnitude higher. Precise fusion measurements have already been performed with those stable weakly bound nuclei, and the effect of breakup of those nuclei on the fusion process has been extensively studied. Those nuclei indicated large production cross sections for particles other than the α + x breakup. The particles are originated from non-capture breakup (NCBU), incomplete fusion (ICF) and transfer processes. However, the conclusion of reaction dynamics was not clear and has the contradiction. In our previous experiments we have performed 6Li+96Zr and 154Sm at HI-13 Tandem accelerator of China Institute of Atomic Energy (CIAE) by using HPGe array. It is shown that there is a small complete fusion (CF) suppression on medium-mass target nucleus 96Zr different from about 35% suppression on heavier target nucleus 154Sm at near-barrier energies. It seems that the CF suppression factor depends on the charge of target nuclei. We also observed one neutron transfer process. However, the experimental data are scarce for medium-mass target nuclei. In order to have a proper understanding of the influence of breakup and transfer of weakly bound projectiles on the fusion process, we performed the 6Li+89Y experiment with incident energies of 22 MeV and 34 MeV on Galileo array in cooperation with Si-ball EUCLIDES at Legnaro National Laboratory (LNL) in Italy. Using particle-particle and particle-γ coincidences, the different reaction mechanisms can be clearly explored.

Importance of lifetime effects in breakup and suppression of complete fusion in reactions of weakly bound nuclei

NASA Astrophysics Data System (ADS)

Cook, K. J.; Simpson, E. C.; Luong, D. H.; Kalkal, Sunil; Dasgupta, M.; Hinde, D. J.

2016-06-01

Background: Complete fusion cross sections in collisions of light weakly bound nuclei and high-Z targets show suppression of complete fusion at above-barrier energies. This has been interpreted as resulting from the breakup of the weakly bound nucleus prior to reaching the fusion barrier, reducing the probability of complete charge capture. Below-barrier studies of reactions of 9Be have found that the breakup of 8Be formed by neutron stripping dominates over direct breakup and that transfer-triggered breakup may account for the observed suppression of complete fusion. Purpose: This paper investigates how the above conclusions are affected by lifetimes of the resonant states that are populated prior to breakup. If the mean life of a populated resonance (above the breakup threshold) is much longer than the fusion time scale, then its breakup (decay) cannot suppress complete fusion. For short-lived resonances, the situation is more complex. This work explicitly includes the mean life of the short-lived 2+ resonance in 8Be in classical dynamical model calculations to determine its effect on energy and angular correlations of the breakup fragments and on model predictions of suppression of cross sections for complete fusion at above-barrier energies. Method: Previously performed coincidence measurements of breakup fragments produced in reactions of 9Be with 144Sm, 168Er, 186W, 196Pt, 208Pb, and 209Bi at energies below the barrier have been reanalyzed using an improved efficiency determination of the BALiN detector array. Predictions of breakup observables and of complete and incomplete fusion at energies above the fusion barrier are then made using the classical dynamical simulation code platypus, modified to include the effect of lifetimes of resonant states. Results: The agreement of the breakup observables is much improved when lifetime effects are included explicitly. Sensitivity to subzeptosecond lifetime is observed. The predicted suppression of complete fusion owing to breakup is nearly independent of Z and has an average value of ˜9 % . This is below the experimentally determined fusion suppression, which is typically ˜30 % in these systems. Conclusions: Inclusion of resonance lifetimes is essential to correctly reproduce breakup observables. This results in a larger fraction of nuclei remaining intact at the fusion-barrier radius compared with calculations that do not explicitly include lifetime effects. The more realistic treatment of breakup followed in this work leads to the conclusion that the suppression of complete fusion cannot be fully explained by breakup prior to reaching the fusion barrier. Only one-third of the observed fusion suppression can be attributed to the competing process of breakup. Other mechanisms that can suppress complete fusion must therefore be investigated. One of the possible candidates is cluster transfer that produces the same heavy targetlike nuclei as those formed by incomplete fusion.

Method for the controlled liberation of fusion nuclear energy (in French)

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

1972-08-18

L'invention concerne des reactions thermonucleaires. Elle se rapporte a un procede de fusion dans lequel de l'energie laser est concentree sur de minuscules spheres de combustible forme de deuterium et de tritium, de maniere a creer d'une part un plasma superficiel assurant un transfert efficace d'energie et d'autre part des ondes de choc convergeant au centre et assurant la fusion nucleaire de la matiere centrale. Ceci est applicable a la production d'energie thermique par fusion nucleaire. (FR)

Cold-fusion television show angers APS

NASA Astrophysics Data System (ADS)

Cartwright, Jon

2009-06-01

Cold fusion has been controversial since its inception on 23 March 1989, when chemists Martin Fleischmann and Stanley Pons at the University of Utah in the US announced that they had achieved a sustained nuclear-fusion reaction at room temperature. Two decades on, a US television documentary about the field has stirred up fresh debate after it linked the American Physical Society (APS) to an evaluation of some cold-fusion results by Robert Duncan, a physicist and vice chancellor of the University of Missouri.

Analytic, empirical and delta method temperature derivatives of D-D and D-T fusion reactivity formulations, as a means of verification

DOE Office of Scientific and Technical Information (OSTI.GOV)

Langenbrunner, James R.; Booker, Jane M.

We examine the derivatives with respect to temperature, for various deuterium-tritium (DT) and deuterium-deuterium (D-D) fusion-reactivity formulations. Langenbrunner and Makaruk [1] had studied this as a means of understanding the time and temperature domain of reaction history measured in dynamic fusion experiments. Presently, we consider the temperature derivative dependence of fusion reactivity as a means of exercising and verifying the consistency of the various reactivity formulations.

Safety and environmental constraints on space applications of fusion energy

NASA Technical Reports Server (NTRS)

Roth, J. Reece

1990-01-01

Some of the constraints are examined on fusion reactions, plasma confinement systems, and fusion reactors that are intended for such space related missions as manned or unmanned operations in near earth orbit, interplanetary missions, or requirements of the SDI program. Of the many constraints on space power and propulsion systems, those arising from safety and environmental considerations are emphasized since these considerations place severe constraints on some fusion systems and have not been adequately treated in previous studies.

Study of Cold Fusion Reactions Using Collective Clusterization Approach

NASA Astrophysics Data System (ADS)

Kaur, Gurjit; Sandhu, Kirandeep; Sharma, Manoj K.

2017-10-01

Within the framework of the dynamical cluster decay model (DCM), the 1n evaporation cross-sections ({σ }1n) of cold fusion reactions (Pb and Bi targets) are calculated for {Z}{CN}=104-113 superheavy nuclei. The calculations are carried out in the fixed range of excitation energy {E}{CN}* =15+/- 1 {MeV}, so that the comparative analysis of reaction dynamics can be worked out. First of all, the fission barriers (B f ) and neutron separation energies ({S}1n) are estimated to account the decreasing cross-sections of cold fusion reactions. In addition to this, the importance of hot optimum orientations of β 2i-deformed nuclei over cold one is explored at fixed angular momentum and neck-length parameters. The hot optimum orientations support all the target-projectile (t,p) combinations, which are explored experimentally in the cold fusion reactions. Some new target-projectile combinations are also predicted for future exploration. Further, the 1n cross-sections are addressed for {Z}{CN}=104-113 superheavy nuclei at comparable excitation energies which show the decent agrement with experimental data upto {Z}{CN}=109 nuclei. Finally, to understand the dynamics of higher-Z superheavy nuclei, the cross-sections are also calculated at maximum available energies around the Coulomb barrier and the effect of non-sticking moment of inertia ({I}{NS}) is also investigated at these energies. Supported by the Council of Scientific and Industrial Research (CSIR), in the Form of Research Project Grant No. 03(1341)/15/EMR-II, and to DST, New Delhi, for INSPIRE-Fellowship Grant No. DST/INSPIRE/03/2015/000199

In-beam fissio study at JAEA for heavy element synthesis

NASA Astrophysics Data System (ADS)

Nishio, K.; Ikezoe, H.; Hofmann, S.; Ackermann, D.; Aritomo, Y.; Comas, V. F.; Düllmann, Ch. E.; Heinz, S.; Heredia, J. A.; Heßberger, F. P.; Hirose, K.; Khuyagbaatar, J.; Kindler, B.; Kojouharov, I.; Lommel, B.; Makii, M.; Mann, R.; Mitsuoka, S.; Nishinaka, I.; Ohtsuki, T.; Saro, S.; Schädel, M.; Popeko, A. G.; Türler, A.; Wakabayashi, Y.; Watanabe, Y.; Yakushev, A.; Yeremin, A.

2013-04-01

Fission fragment mass distributions were measured in the heavy-ion induced fission using 238U target nucleus. The mass distributions changed drastically with incident energy. The results are explained by a change of the ratio between fusion and qasifission with nuclear orientation. A calculation based on a fluctuation dissipation model reproduced the mass distributions and their incident energy dependence. Fusion probability was determined in the analysis. Evaporation residue cross sections were calculated with a statistical model in the reactions of 30Si+238U and 34S+238U using the obtained fusion probability in the entrance channel. The results agree with the measured cross sections of 263,264Sg and 267,268Hs, produced by 30Si+238U and 34S+238U, respectively. It is also suggested that the sub-barrier energies can be used for heavy element synthesis.

Modeling the Compression of Merged Compact Toroids by Multiple Plasma Jets

NASA Technical Reports Server (NTRS)

Thio, Y. C. Francis; Knapp, Charles E.; Kirkpatrick, Ron; Rodgers, Stephen L. (Technical Monitor)

2000-01-01

A fusion propulsion scheme has been proposed that makes use of the merging of a spherical distribution of plasma jets to dynamically form a gaseous liner. The gaseous liner is used to implode a magnetized target to produce the fusion reaction in a standoff manner. In this paper, the merging of the plasma jets to form the gaseous liner is investigated numerically. The Los Alamos SPHINX code, based on the smoothed particle hydrodynamics method is used to model the interaction of the jets. 2-D and 3-D simulations have been performed to study the characteristics of the resulting flow when these jets collide. The results show that the jets merge to form a plasma liner that converge radially which may be used to compress the central plasma to fusion conditions. Details of the computational model and the SPH numerical methods will be presented together with the numerical results.

Why You Should Believe Cold Fusion is Real

NASA Astrophysics Data System (ADS)

Storms, Edmund K.

2005-03-01

Nuclear reactions are now claimed to be initiated in certain solid materials at an energy too low to overcome the Coulomb barrier. These reactions include fusion, accelerated radioactive decay, and transmutation involving heavy elements. Evidence is based on hundreds of measurements of anomalous energy using a variety of calorimeters at levels far in excess of error, measurement of nuclear products using many normally accepted techniques, observations of many patterns of behavior common to all studies, measurement of anomalous energetic emissions using accepted techniques, and an understanding of most variables that have hindered reproducibility in the past. This evidence can be found at www.LENR-CANR.orgwww.LENR-CANR.org. Except for an accepted theory, the claims have met all requirements normally required before a new idea is accepted by conventional science, yet rejection continues. How long can the US afford to reject a clean and potentially cheap source of energy, especially when other nations are attempting to develop this energy and the need for such an energy source is so great?

Study on reaction mechanism by analysis of kinetic energy spectra of light particles and formation of final products

NASA Astrophysics Data System (ADS)

Giardina, G.; Mandaglio, G.; Nasirov, A. K.; Anastasi, A.; Curciarello, F.; Fazio, G.

2018-05-01

The sensitivity of reaction mechanism in the formation of compound nucleus (CN) by the analysis of kinetic energy spectra of light particles and of reaction products are shown. The dependence of the P CN fusion probability of reactants and W sur survival probability of CN against fission at its deexcitation on the mass and charge symmetries in the entrance channel of heavy-ion collisions, as well as on the neutron numbers is discussed. The possibility of conducting a complex program of investigations of the complete fusion by reliable ways depends on the detailed and refined methods of experimental and theoretical analyses.

Upgrade of the IGN-14 neutron generator for research on detection of fusion-plasma products

NASA Astrophysics Data System (ADS)

Igielski, Andrzej; Kurowski, Arkadiusz; Janik, Władysław; Gabańska, Barbara; Woźnicka, Urszula

2015-10-01

The fast neutron generator (IGN-14) at the Institute of Nuclear Physics of the Polish Academy of Sciences (IFJ PAN) in Kraków (Poland) is a laboratory multi-purpose experimental device. Neutrons are produced in a beam-target D-D or D-T reactions. A new vacuum chamber installed directly to the end of the ion guide of IGN-14 makes it possible to measure not only neutrons but also alpha particles in the presence of a mixed radiation field of other accompanying reaction products. The new experimental setup allows test detectors dedicated to spectrometric measurements of thermonuclear fusion reaction products.

Fission fragment angular distributions in the reactions {sup 16}O+{sup 188}Os and {sup 28}Si+{sup 176}Yb

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tripathi, R.; Sudarshan, K.; Sharma, S. K.

2009-06-15

Fission fragment angular distributions have been measured in the reactions {sup 16}O+{sup 188}Os and {sup 28}Si+{sup 176}Yb to investigate the contribution from noncompound nucleus fission. Parameters for statistical model calculations were fixed using fission cross section data in the {sup 16}O+{sup 188}Os reaction. Experimental anisotropies were in reasonable agreement with those calculated using the statistical saddle point model for both reactions. The present results are also consistent with those of mass distribution studies in the fission of {sup 202}Po, formed in the reactions with varying entrance channel mass asymmetry. However, the present studies do not show a large fusion hindrancemore » as reported in the pre-actinide region based on the measurement of evaporation residue cross section.« less

Fusion and direct reactions around the barrier for the systems {sup 7,9}Be,{sup 7}Li+{sup 238}U

DOE Office of Scientific and Technical Information (OSTI.GOV)

Raabe, R.; Angulo, C.; Charvet, J. L.

2006-10-15

We present new cross section data for the complete fusion of the weakly bound systems {sup 7,9}Be and {sup 7}Li on {sup 238}U at energies around the Coulomb barrier. In the same measurement, yields for direct processes and incomplete fusion are detected. For all systems, a suppression of the complete fusion cross section around and above the barrier is observed. At energies below the barrier, the fusion of the {sup 7}Be+{sup 238}U system shows no enhancement with respect to simple model predictions.

Measurement of the ^12C+^12C Fusion Reaction with MUSIC

NASA Astrophysics Data System (ADS)

Carnelli, P. F. F.; Almaraz-Calderon, S.; Henderson, D.; Rehm, K. E.; Albers, M.; Alcorta, M.; Bertone, P. F.; Esbensen, H.; Fernandez-Niello, J. O.; Jiang, C. L.; Lighthall, J. C.; Marley, S. T.; Palchan-Hazan, T.; Pardo, R. C.; Paul, M.

2012-10-01

The fusion of the ^12C+^12C system is of great interest in nuclear structure and nuclear astrophysics. Above the Coulomb barrier, the excitation function of this system exhibits oscillations, which are not well understood. There is also a significant discrepancy between the experimental fusion cross-section and recent coupled-channel calculations that is not present in other carbon systems. To address these issues, we have re-measured the fusion excitation function for ^12,13C+^12C in the energy range of 10 MeV < Ecm < 20 MeV using a Multi-Sampling Ionization Chamber (MUSIC) detector. The gas of the ionization chamber (CH4) served as both the target material and the counter gas. One of the main advantages of this method is that the excitation function is measured over a large range of energies using only one beam energy. This method has been proven to be successful and it will be used to measure fusion reactions in other light systems. The experimental results will be presented and compared to previous experimental data and theoretical models.

7Li-induced reaction on natMo: A study of complete versus incomplete fusion

NASA Astrophysics Data System (ADS)

Kumar, Deepak; Maiti, Moumita; Lahiri, Susanta

2017-07-01

Background: Several investigations on the complete-incomplete fusion (CF-ICF) dynamics of α -cluster well-bound nuclei have been contemplated above the Coulomb barrier (˜4 -7 MeV/nucleon) in recent years. It is therefore expected to observe significant ICF over CF in the reactions induced by a weakly bound α -cluster nucleus at slightly above the barrier. Purpose: Study of the CF-ICF dynamics by measuring the populated residues in the weakly bound 7Li+natMo system at energies slightly above the Coulomb barrier to well above it. Method: In order to investigate CF-ICF in the loosely bound system, 7Li beam was bombarded on the natMo foils, separated by the aluminium (Al) catcher foils alternatively, within ˜3 -6.5 MeV/nucleon. Evaporation residues produced in each foil were identified by the off-line γ -ray spectrometry. Measured cross section data of the residues were compared with the theoretical model calculations based on the equilibrium (EQ) and pre-equilibrium (PEQ) reaction mechanisms. Results: The experimental cross section of Rh 101 m,100 ,99 m,97 ,Ru,9597,Tc 99 m,96 ,95 ,94 ,93 m+g , and 93mMo residues measured at various projectile energies were satisfactorily reproduced by the simplified coupled channel approach in comparison to single barrier penetration model calculation. Significant cross section enhancement in the α -emitting channels was observed compared to EQ and PEQ model calculations throughout observed energy region. The ICF process over CF was analyzed by comparing with EMPIRE. The increment of the incomplete fusion fraction was observed with increasing projectile energies. Conclusions: Theoretical model calculations reveal that the compound reaction mechanism is the major contributor to the production of residues in 7Li+natMo reaction. Theoretical evaluations substantiate the contribution of ICF over the CF in α -emitting channels. EMPIRE estimations shed light on its predictive capability of cross sections of the residues from the heavy-ion induced reactions.

Quantum partner-dance in the 12C + 12C system yields sub-Coulomb fusion resonances

NASA Astrophysics Data System (ADS)

Diaz-Torres, Alexis; Wiescher, Michael

2014-03-01

A preliminary study of the 12C + 12C sub-Coulomb fusion reaction using the time-dependent wave-packet method is presented. The theoretical sub-Coulomb fusion resonances seem to correspond well with observations. The present method might be a more suitable tool for expanding the cross-section predictions towards lower energies than the commonly used potential-model approximation.

Nuclear science experiments with a bright neutron source from fusion reactions on the OMEGA Laser System

NASA Astrophysics Data System (ADS)

Forrest, C. J.; Knauer, J. P.; Schroeder, W. U.; Glebov, V. Yu.; Radha, P. B.; Regan, S. P.; Sangster, T. C.; Sickles, M.; Stoeckl, C.; Szczepanski, J.

2018-04-01

Subnanosecond impulses of 1013 to 1014 neutrons, produced in direct-drive laser inertial confinement fusion implosions, have been used to irradiate deuterated targets at the OMEGA Laser System (Boehly et al., 1997). The target compounds include heavy water (D2O) and deuterated benzene (C6D6). Yields and energy spectra of neutrons from D(n,2n)p to study the breakup reaction have been measured at a forward angle of θlab = 3 .5∘ ± 3.5° with a sensitive, high-dynamic-range neutron time-of-flight spectrometer to infer the double-differential breakup cross section d2 σ/dE d Ω for 14-MeV D-T fusion neutrons.

Magnetic Reconnection Driven by Thermonuclear Burning

NASA Astrophysics Data System (ADS)

Gatto, R.; Coppi, B.

2017-10-01

Considering that fusion reaction products (e.g. α-particles) deposit their energy on the electrons, the relevant thermal energy balance equation is characterized by a fusion source term, a relatively large longitudinal thermal conductivity and an appropriate transverse thermal conductivity. Then, looking for modes that are radially localized around rational surfaces, reconnected field configurations are found that can be sustained by the electron thermal energy source due to fusion reactions. Then this process can be included in the category of endogenous reconnection processes and may be viewed as a form of the thermonuclear instability that can develop in an ignited inhomogeneous plasma. A complete analysis of the equations supporting the relevant theory is reported. Sponsored in part by the U.S. DoE.

A Blood-based Test for the Detection of ROS1 and RET Fusion Transcripts from Circulating Ribonucleic Acid Using Digital Polymerase Chain Reaction

PubMed Central

Mellert, Hestia S.; Alexander, Kristin E.; Jackson, Leisa P.; Pestano, Gary A.

2018-01-01

We have developed novel methods for the isolation and characterization of tumor-derived circulating ribonucleic acid (cRNA) for blood-based liquid biopsy. Robust detection of cRNA recovered from blood represents a solution to a critical unmet need in clinical diagnostics. The test begins with the collection of whole blood into blood collection tubes containing preservatives that stabilize cRNA. Cell-free, exosomal, and platelet-associated RNA is isolated from plasma in this test system. The cRNA is reverse transcribed to complementary DNA (cDNA) and amplified using digital polymerase chain reaction (dPCR). Samples are evaluated for both the target biomarker as well as a control gene. Test validation included limit of detection, accuracy, and robustness studies with analytic samples. The method developed as a result of these studies reproducibly detect multiple fusion variants for ROS1 (C-Ros proto-oncogene 1; 8 variants) and RET (rearranged during transfection proto-oncogene; 8 variants). The sample processing workflow has been optimized so that test results can consistently be generated within 72 hours of sample receipt. PMID:29683453

Modeling of hydrogen/deuterium dynamics and heat generation on palladium nanoparticles for hydrogen storage and solid-state nuclear fusion.

PubMed

Tanabe, Katsuaki

2016-01-01

We modeled the dynamics of hydrogen and deuterium adsorbed on palladium nanoparticles including the heat generation induced by the chemical adsorption and desorption, as well as palladium-catalyzed reactions. Our calculations based on the proposed model reproduce the experimental time-evolution of pressure and temperature with a single set of fitting parameters for hydrogen and deuterium injection. The model we generated with a highly generalized set of formulations can be applied for any combination of a gas species and a catalytic adsorbent/absorbent. Our model can be used as a basis for future research into hydrogen storage and solid-state nuclear fusion technologies.

Membrane Fusion Involved in Neurotransmission: Glimpse from Electron Microscope and Molecular Simulation

PubMed Central

Yang, Zhiwei; Gou, Lu; Chen, Shuyu; Li, Na; Zhang, Shengli; Zhang, Lei

2017-01-01

Membrane fusion is one of the most fundamental physiological processes in eukaryotes for triggering the fusion of lipid and content, as well as the neurotransmission. However, the architecture features of neurotransmitter release machinery and interdependent mechanism of synaptic membrane fusion have not been extensively studied. This review article expounds the neuronal membrane fusion processes, discusses the fundamental steps in all fusion reactions (membrane aggregation, membrane association, lipid rearrangement and lipid and content mixing) and the probable mechanism coupling to the delivery of neurotransmitters. Subsequently, this work summarizes the research on the fusion process in synaptic transmission, using electron microscopy (EM) and molecular simulation approaches. Finally, we propose the future outlook for more exciting applications of membrane fusion involved in synaptic transmission, with the aid of stochastic optical reconstruction microscopy (STORM), cryo-EM (cryo-EM), and molecular simulations. PMID:28638320

Skyrme forces and decay of the Rf266*104 nucleus synthesized via different incoming channels

NASA Astrophysics Data System (ADS)

Niyti, Deep, Aman; Kharab, Rajesh; Chopra, Sahila; Gupta, Raj K.

2017-03-01

The excitation functions for the production of 262Rf, 261Rf, and 260Rf isotopes via 4 n -, 5 n -, and 6 n -decay channels from the *266Rf compound nucleus are studied within the dynamical cluster-decay model (DCM), including deformations β2 i and so-called hot-optimum orientations θi which support symmetric fission, in agreement with experiments. The data are available for 18O+248Cm and 22Ne+244Pu reactions, respectively, at the energy ranges of Elab=88.2 to 101.3 and 109.0 to 124.8 MeV. For the nuclear interaction potentials, we use the Skyrme energy density functional (SEDF) based on semiclassical extended Thomas Fermi (ETF) approach, which means an extension of the earlier study of excitation functions of *266Rf formed in 18O+248Cm reaction, based on the DCM using the pocket formula for nuclear proximity potential, showing interaction dependence. The Skyrme forces used here are the old SIII and SIV and new GSkI and KDE0(v1) given for both normal and isospin-rich nuclei, with densities added in frozen density approximation. Interestingly, the DCM gives an excellent fit to the measured data on fusion evaporation residue (ER) for both the incoming channels (18O+248Cm and 22Ne+244Pu ) at the energy range Elab=88.2 to 124.8 MeV, independent of the entrance channel and Skyrme force used. The possible fusion-fission (ff) and quasifission (qf) mass regions of fragments on DCM are also predicted. The DCM with Skyrme forces is further used to look for all the possible target-projectile (t-p) combinations forming the cold compound nucleus (CN) *266Rf at the CN excitation energy of Elab for hot compact configurations. The fusion evaporation residue cross sections, for the proposed new reactions in synthesizing the CN *266Rf, are also estimated for the future experiments, and role of mass asymmetry of nuclei is indicated.

A model for explaining fusion suppression using classical trajectory method

NASA Astrophysics Data System (ADS)

Phookan, C. K.; Kalita, K.

2015-01-01

We adopt a semi-classical approach for explanation of projectile breakup and above barrier fusion suppression for the reactions 6Li+152Sm and 6Li+144Sm. The cut-off impact parameter for fusion is determined by employing quantum mechanical ideas. Within this cut-off impact parameter for fusion, the fraction of projectiles undergoing breakup is determined using the method of classical trajectory in two-dimensions. For obtaining the initial conditions of the equations of motion, a simplified model of the 6Li nucleus has been proposed. We introduce a simple formula for explanation of fusion suppression. We find excellent agreement between the experimental and calculated fusion cross section. A slight modification of the above formula for fusion suppression is also proposed for a three-dimensional model.

Fusion cross sections for reactions involving medium and heavy nucleus-nucleus systems

NASA Astrophysics Data System (ADS)

Atta, Debasis; Basu, D. N.

2014-12-01

Existing data on near-barrier fusion excitation functions of medium and heavy nucleus-nucleus systems have been analyzed by using a simple diffused-barrier formula derived assuming the Gaussian shape of the barrier-height distributions. The fusion cross section is obtained by folding the Gaussian barrier distribution with the classical expression for the fusion cross section for a fixed barrier. The energy dependence of the fusion cross section, thus obtained, provides good description to the existing data on near-barrier fusion and capture excitation functions for medium and heavy nucleus-nucleus systems. The theoretical values for the parameters of the barrier distribution are estimated which can be used for fusion or capture cross-section predictions that are especially important for planning experiments for synthesizing new superheavy elements.

Light charged particle multiplicities in fusion and quasifission reactions

NASA Astrophysics Data System (ADS)

Kalandarov, Sh. A.; Adamian, G. G.; Antonenko, N. V.; Lacroix, D.; Wieleczko, J. P.

2018-01-01

The light charged particle evaporation from the compound nucleus and from the complex fragments in the reactions 32S+100Mo, 121Sb+27Al, 40Ar+164Dy, and 40Ar+ nat Ag is studied within the dinuclear system model. The possibility to distinguish the reaction products from different reaction mechanisms is discussed.

A Burning Plasma Experiment: the role of international collaboration

NASA Astrophysics Data System (ADS)

Prager, Stewart

2003-04-01

The world effort to develop fusion energy is at the threshold of a new stage in its research: the investigation of burning plasmas. A burning plasma is self-heated. The 100 million degree temperature of the plasma is maintained by the heat generated by the fusion reactions themselves, as occurs in burning stars. The fusion-generated alpha particles produce new physical phenomena that are strongly coupled together as a nonlinear complex system, posing a major plasma physics challenge. Two attractive options are being considered by the US fusion community as burning plasma facilities: the international ITER experiment and the US-based FIRE experiment. ITER (the International Thermonuclear Experimental Reactor) is a large, power-plant scale facility. It was conceived and designed by a partnership of the European Union, Japan, the Soviet Union, and the United States. At the completion of the first engineering design in 1998, the US discontinued its participation. FIRE (the Fusion Ignition Research Experiment) is a smaller, domestic facility that is at an advanced pre-conceptual design stage. Each facility has different scientific, programmatic and political implications. Selecting the optimal path for burning plasma science is itself a challenge. Recently, the Fusion Energy Sciences Advisory Committee recommended a dual path strategy in which the US seek to rejoin ITER, but be prepared to move forward with FIRE if the ITER negotiations do not reach fruition by July, 2004. Either the ITER or FIRE experiment would reveal the behavior of burning plasmas, generate large amounts of fusion power, and be a huge step in establishing the potential of fusion energy to contribute to the world's energy security.

CR-39 track detector calibration for H, He, and C ions from 0.1-0.5 MeV up to 5 MeV for laser-induced nuclear fusion product identification.

PubMed

Baccou, C; Yahia, V; Depierreux, S; Neuville, C; Goyon, C; Consoli, F; De Angelis, R; Ducret, J E; Boutoux, G; Rafelski, J; Labaune, C

2015-08-01

Laser-accelerated ion beams can be used in many applications and, especially, to initiate nuclear reactions out of thermal equilibrium. We have experimentally studied aneutronic fusion reactions induced by protons accelerated by the Target Normal Sheath Acceleration mechanism, colliding with a boron target. Such experiments require a rigorous method to identify the reaction products (alpha particles) collected in detectors among a few other ion species such as protons or carbon ions, for example. CR-39 track detectors are widely used because they are mostly sensitive to ions and their efficiency is near 100%. We present a complete calibration of CR-39 track detector for protons, alpha particles, and carbon ions. We give measurements of their track diameters for energy ranging from hundreds of keV to a few MeV and for etching times between 1 and 8 h. We used these results to identify alpha particles in our experiments on proton-boron fusion reactions initiated by laser-accelerated protons. We show that their number clearly increases when the boron fuel is preformed in a plasma state.

CR-39 track detector calibration for H, He, and C ions from 0.1-0.5 MeV up to 5 MeV for laser-induced nuclear fusion product identification

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baccou, C., E-mail: claire.baccou@polytechnique.edu; Yahia, V.; Labaune, C.

Laser-accelerated ion beams can be used in many applications and, especially, to initiate nuclear reactions out of thermal equilibrium. We have experimentally studied aneutronic fusion reactions induced by protons accelerated by the Target Normal Sheath Acceleration mechanism, colliding with a boron target. Such experiments require a rigorous method to identify the reaction products (alpha particles) collected in detectors among a few other ion species such as protons or carbon ions, for example. CR-39 track detectors are widely used because they are mostly sensitive to ions and their efficiency is near 100%. We present a complete calibration of CR-39 track detectormore » for protons, alpha particles, and carbon ions. We give measurements of their track diameters for energy ranging from hundreds of keV to a few MeV and for etching times between 1 and 8 h. We used these results to identify alpha particles in our experiments on proton-boron fusion reactions initiated by laser-accelerated protons. We show that their number clearly increases when the boron fuel is preformed in a plasma state.« less

Application of proton boron fusion reaction to radiation therapy: A Monte Carlo simulation study

NASA Astrophysics Data System (ADS)

Yoon, Do-Kun; Jung, Joo-Young; Suh, Tae Suk

2014-12-01

Three alpha particles are emitted from the point of reaction between a proton and boron. The alpha particles are effective in inducing the death of a tumor cell. After boron is accumulated in the tumor region, the emitted from outside the body proton can react with the boron in the tumor region. An increase of the proton's maximum dose level is caused by the boron and only the tumor cell is damaged more critically. In addition, a prompt gamma ray is emitted from the proton boron reaction point. Here, we show that the effectiveness of the proton boron fusion therapy was verified using Monte Carlo simulations. We found that a dramatic increase by more than half of the proton's maximum dose level was induced by the boron in the tumor region. This increase occurred only when the proton's maximum dose point was located within the boron uptake region. In addition, the 719 keV prompt gamma ray peak produced by the proton boron fusion reaction was positively detected. This therapy method features the advantages such as the application of Bragg-peak to the therapy, the accurate targeting of tumor, improved therapy effects, and the monitoring of the therapy region during treatment.

On the synergy of nuclear data for fusion and model assumptions

NASA Astrophysics Data System (ADS)

Avrigeanu, Vlad; Avrigeanu, Marilena

2017-09-01

A deuteron breakup (BU) parametrization is involved within the BU analysis of recently measured reaction-in-flight (RIF) neutron time-of-flight spectrum, while open questions underlined previously on related fast-neutron induced reaction on Zr isotopes are also addressed in a consistent way, at once with the use of a recent optical potential for α-particles to understand the large discrepancy between the measured and calculated cross sections of the 94Zr(n,α)91Sr reaction. Thus the synergy between the above-mentioned three distinct subjects may finally lead to smaller uncertainties of the nuclear data for fusion while the RIF neutron spectra may also be used to support nuclear model assumptions.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jiang, C. L.; Santiago-Gonzalez, D.; Almaraz-Calderon, S.

Carbon burning is a critical phase for nucleosynthesis in massive stars. The conditions for igniting this burning stage, and the subsequent isotope composition of the resulting ashes, depend strongly on the reaction rate for 12C+ 12C fusion at very low energies. Results for the cross sections for this reaction are influenced by various backgrounds encountered in measurements at such energies. In this paper, we report on a new measurement of 12C+ 12C fusion cross sections where these backgrounds have been minimized. In conclusion, it is found that the astrophysical S factor exhibits a maximum around E cm=3.5–4.0 MeV, which leadsmore » to a reduction of the previously predicted astrophysical reaction rate.« less

Nuclear diagnostic for fast alpha particles

DOEpatents

Grisham, Larry R.; Post Jr., Douglass E.; Dawson, John M.

1986-06-03

Measurement of the velocity distribution of confined energetic alpha particles resulting from deuterium-tritium fusion reactions in a magnetically contained plasma is provided. The fusion plasma is seeded with energetic boron neutrals for producing, by means of the reaction .sup.10 B (.alpha.,n) .sup.13 N reaction, radioactive nitrogen nuclei which are then collected by a probe. The radioactivity of the probe is then measured by conventional techniques in determining the energy distribution of the alpha particles in the plasma. In a preferred embodiment, diborane gas (B.sub.2 H.sub.6) is the source of the boron neutrals to produce .sup.13 N which decays almost exclusively by positron emission with a convenient half-life of 10 minutes.

Nuclear diagnostic for fast alpha particles

DOEpatents

Grisham, Larry R.; Post, Jr., Douglass E.; Dawson, John M.

1986-01-01

Measurement of the velocity distribution of confined energetic alpha particles resulting from deuterium-tritium fusion reactions in a magnetically contained plasma is provided. The fusion plasma is seeded with energetic boron neutrals for producing, by means of the reaction .sup.10 B (.alpha.,n) .sup.13 N reaction, radioactive nitrogen nuclei which are then collected by a probe. The radioactivity of the probe is then measured by conventional techniques in determining the energy distribution of the alpha particles in the plasma. In a preferred embodiment, diborane gas (B.sub.2 H.sub.6) is the source of the boron neutrals to produce .sup.13 N which decays almost exclusively by positron emission with a convenient half-life of 10 minutes.

Novel Role of Superfluidity in Low-Energy Nuclear Reactions.

PubMed

Magierski, Piotr; Sekizawa, Kazuyuki; Wlazłowski, Gabriel

2017-07-28

We demonstrate, within symmetry unrestricted time-dependent density functional theory, the existence of new effects in low-energy nuclear reactions which originate from superfluidity. The dynamics of the pairing field induces solitonic excitations in the colliding nuclear systems, leading to qualitative changes in the reaction dynamics. The solitonic excitation prevents collective energy dissipation and effectively suppresses the fusion cross section. We demonstrate how the variations of the total kinetic energy of the fragments can be traced back to the energy stored in the superfluid junction of colliding nuclei. Both contact time and scattering angle in noncentral collisions are significantly affected. The modification of the fusion cross section and possibilities for its experimental detection are discussed.

Synthesis reactions and radioactive properties of transactinoid elements

NASA Astrophysics Data System (ADS)

Oganessian, Yu. Ts.

1994-10-01

It is well known that the heaviest elements of the periodic table have been synthesized in the cold fusion of magic nuclei of Pb with Z less than 26 ions. Because of dynamic limitations for fusion under strong Coulomb interaction of nuclei, the cross-sections of cold fusion reactions diminish exponentially with growing compound nucleus atomic number. For element Z = 110 produced in the reaction Pb-208(Ni-62,n)(sub 271)110, the expected cross-section is 10(exp -36) sq cm. In still more asymmetric reactions, when isotopes of actinoid elements irradiated with relatively light ions (Z less than or equal 12) are used as the target material, the compound nuclei possess an excitation energy of approx. 50 MeV. At this energy the nuclear shell effects are strongly suppressed and, as a result, in the case of hot compound nuclei of transactinoid elements the fission barrier is practically absent. The transition of these nuclei into the ground state depends strongly on the dynamic properties of the system with respect to the fission degree of freedom. Experimental studies were going on in two directions: (1) determination of the fission time by measuring the prefission neutrons (of Cf-Fm nuclei) in a wide interval of excitation energies; (2) direct synthesis of known nuclides with Z = 102-105 in reactions with ions of Ne-22, Mg-26, Al-27 and P-31 when final nuclei are produced in the ground state after the evaporation of five or six neutrons from the excited compound nuclei (E(sub x) = 50-60 MeV). The dependence of the reaction cross-section (HI, 5-6n) on the atomic number of the compound nucleus in different target-ion combinations points to the possibility of synthesizing new elements in hot fusion reactions. The advantage of these reactions arises from the use of neutron-rich nuclei like Cm-248 and Cf-249 which allows us to synthesize nuclei close to the deformed shell N = 162, for which a considerable growth of stability against spontaneous fission is predicted. Experimental set-ups and methods of detecting rare events of formation and decay of transactinide nuclei are described.

Sensitivity of low-energy incomplete fusion to various entrance-channel parameters

NASA Astrophysics Data System (ADS)

Kumar, Harish; Tali, Suhail A.; Afzal Ansari, M.; Singh, D.; Ali, Rahbar; Kumar, Kamal; Sathik, N. P. M.; Ali, Asif; Parashari, Siddharth; Dubey, R.; Bala, Indu; Kumar, R.; Singh, R. P.; Muralithar, S.

2018-03-01

The disentangling of incomplete fusion dependence on various entrance channel parameters has been made from the forward recoil range distribution measurement for the 12C+175Lu system at ≈ 88 MeV energy. It gives the direct measure of full and/or partial linear momentum transfer from the projectile to the target nucleus. The comparison of observed recoil ranges with theoretical ranges calculated using the code SRIM infers the production of evaporation residues via complete and/or incomplete fusion process. Present results show that incomplete fusion process contributes significantly in the production of α xn and 2α xn emission channels. The deduced incomplete fusion probability (F_{ICF}) is compared with that obtained for systems available in the literature. An interesting behavior of F_{ICF} with ZP ZT is observed in the reinvestigation of incomplete fusion dependency with the Coulomb factor (ZPZT), contrary to the recent observations. The present results based on (ZPZT) are found in good agreement with recent observations of our group. A larger F_{ICF} value for 12C induced reactions is found than that for 13C, although both have the same ZPZT. A nonsystematic behavior of the incomplete fusion process with the target deformation parameter (β2) is observed, which is further correlated with a new parameter (ZP ZT . β2). The projectile α -Q-value is found to explain more clearly the discrepancy observed in incomplete fusion dependency with parameters ( ZPZT) and (ZP ZT . β2). It may be pointed out that any single entrance channel parameter (mass-asymmetry or (ZPZT) or β2 or projectile α-Q-value) may not be able to explain completely the incomplete fusion process.

Final Progress Report The U.S. Department of Energy Research Grant No. DE-SC0008660 Plasma Surface Interactions: Bridging from the Surface to the Micron Frontier through Leadership Class Computing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krasheninnikov, Sergei; Smirnov, Roman; Guterl, Jerome

The choice of material for the plasma facing components (PFC), in particular, for divertor targets, is one of the main issues for future tokamak reactors. There are two major requirements for the PFC’s material: acceptable level of tritium retention and durability in a harsh environment of fusion grade plasma. Based on these criteria, some years ago it was decided that tungsten is an acceptable material for divertor targets in ITER. However, further experimental studies reveal that the irradiation of tungsten even with low energetic (well below sputtering threshold!) He containing plasma causes significant modification of surface morphology, formation of themore » layer of He nano-bubbles (in the temperature range T<1000 K), “fuzz” (for 1000 K2000 K) (e.g. see Fig. 1). Recall that He, being an ash of D-T fusion reactions, is an inherent impurity in fusion plasma. The goals of the UCSD Applied Plasma Theory Group was: i) investigate the mechanisms of the formation of He nano-bubble layer and fuzz growth under He irradiation, as well as the physics of transport of hydrogen species in tungsten lattice, and ii) develop physics understanding of the models suitable for the incorporation into the Xolotl-PSI code based on the reaction-diffusion approach, which is the flagship of the whole SciDAC project [8], which can guide both numerical simulations and experimental studies. Here we just highlight our major accomplishments.« less

Energy spectrum of 208Pb(n,x) reactions

NASA Astrophysics Data System (ADS)

Tel, E.; Kavun, Y.; Özdoǧan, H.; Kaplan, A.

2018-02-01

Fission and fusion reactor technologies have been investigated since 1950's on the world. For reactor technology, fission and fusion reaction investigations are play important role for improve new generation technologies. Especially, neutron reaction studies have an important place in the development of nuclear materials. So neutron effects on materials should study as theoretically and experimentally for improve reactor design. For this reason, Nuclear reaction codes are very useful tools when experimental data are unavailable. For such circumstances scientists created many nuclear reaction codes such as ALICE/ASH, CEM95, PCROSS, TALYS, GEANT, FLUKA. In this study we used ALICE/ASH, PCROSS and CEM95 codes for energy spectrum calculation of outgoing particles from Pb bombardment by neutron. While Weisskopf-Ewing model has been used for the equilibrium process in the calculations, full exciton, hybrid and geometry dependent hybrid nuclear reaction models have been used for the pre-equilibrium process. The calculated results have been discussed and compared with the experimental data taken from EXFOR.

Method and apparatus to produce high specific impulse and moderate thrust from a fusion-powered rocket engine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cohen, Samuel A.; Pajer, Gary A.; Paluszek, Michael A.

A system and method for producing and controlling high thrust and desirable specific impulse from a continuous fusion reaction is disclosed. The resultant relatively small rocket engine will have lower cost to develop, test, and operate that the prior art, allowing spacecraft missions throughout the planetary system and beyond. The rocket engine method and system includes a reactor chamber and a heating system for heating a stable plasma to produce fusion reactions in the stable plasma. Magnets produce a magnetic field that confines the stable plasma. A fuel injection system and a propellant injection system are included. The propellant injectionmore » system injects cold propellant into a gas box at one end of the reactor chamber, where the propellant is ionized into a plasma. The propellant and fusion products are directed out of the reactor chamber through a magnetic nozzle and are detached from the magnetic field lines producing thrust.« less

Dynamics of 17F + 58Ni reaction via complete and incomplete fusion processes at above barrier energies

NASA Astrophysics Data System (ADS)

Grover, Neha; Sandhu, Kirandeep; Sharma, Manoj K.

2018-06-01

The dynamics of 17F + 58Ni reaction induced via a loosely bound projectile (17F) is examined using the collective clusterization approach of the dynamical cluster decay model (DCM) with respect to the recent experimental data available at beam energies Ebeam = 54.1 and 58.5 MeV. The calculations are done for quadrupole deformations of fragments using the optimum orientation approach. In view of the loosely bound nature of 17F, the main focus of the present work is on the comparison of complete and incomplete fusion. It is studied using various components such as fragmentation potential, mass distribution, and barrier modification. Different decay modes (ER, IMF, HMF, and fission) are also compared to determine the complete fusion and incomplete fusion paths. Additionally, the decay paths of the nucleus formed from loosely bound (17F) and tightly bound (16O) projectiles are compared. Furthermore, the role of temperature-dependent pairing strength is analyzed in terms of the binary fragmentation of the compound system formed.

Low-energy (anti)neutrino physics with Borexino: Neutrinos from the primary proton-proton fusion process in the Sun

NASA Astrophysics Data System (ADS)

Mosteiro, P.; Bellini, G.; Benziger, J.; Bick, D.; Bonfini, G.; Bravo, D.; Caccianiga, B.; Cadonati, L.; Calaprice, F.; Caminata, A.; Cavalcante, P.; Chavarría, Á.; Chepurnov, A.; D'Angelo, D.; Davini, S.; Derbin, A.; Empl, A.; Etenko, A.; Fomenko, K.; Franco, D.; Gabriele, F.; Galbiati, C.; Gazzana, S.; Ghiano, C.; Giammarchi, M.; Göger-Neff, M.; Goretti, A.; Gromov, M.; Hagner, C.; Hungerford, E.; Ianni, Al.; Ianni, An.; Kobychev, V.; Korablëv, D.; Korga, G.; Kryn, D.; Laubenstein, M.; Lehnert, B.; Lewke, T.; Litvinovich, E.; Lombardi, F.; Lombardi, P.; Ludhova, L.; Lukyanchenko, G.; Machulin, I.; Manecki, S.; Maneschg, W.; Marcocci, S.; Meindl, Q.; Meroni, E.; Meyer, M.; Miramonti, L.; Misiaszek, M.; Montuschi, M.; Muratova, V.; Oberauer, L.; Obolensky, M.; Ortica, F.; Otis, K.; Pallavicini, M.; Papp, L.; Perasso, L.; Pocar, A.; Ranucci, G.; Razeto, A.; Re, A.; Romani, A.; Rossi, N.; Saldanha, R.; Salvo, C.; Schönert, S.; Simgen, H.; Skorokhvatov, M.; Smirnov, O.; Sotnikov, A.; Sukhotin, S.; Suvorov, Y.; Tartaglia, R.; Testera, G.; Vignaud, D.; Vogelaar, R. B.; von Feilitzsch, F.; Wang, H.; Winter, J.; Wojcik, M.; Wright, A.; Wurm, M.; Zaimidoroga, O.; Zavatarelli, S.; Zuber, K.; Zuzel, G.

2015-08-01

The Sun is fueled by a series of nuclear reactions that produce the energy that makes it shine. The primary reaction is the fusion of two protons into a deuteron, a positron and a neutrino. These neutrinos constitute the vast majority of neutrinos reaching Earth, providing us with key information about what goes on at the core of our star. Several experiments have now confirmed the observation of neutrino oscillations by detecting neutrinos from secondary nuclear processes in the Sun; this is the first direct spectral measurement of the neutrinos from the keystone proton-proton fusion. This observation is a crucial step towards the completion of the spectroscopy of pp-chain neutrinos, as well as further validation of the LMA-MSW model of neutrino oscillations.

Microscale Syntheses, Reactions, and 1H NMR Spectroscopic Investigations of Square Planar Macrocyclic Tetraamido-N Cu(III) Complexes Relevant to Green Chemistry

ERIC Educational Resources Information Center

Uffelman, Erich S.; Doherty, Jonathan R.; Schulze, Carl; Burke, Amy L.; Bonnema, Kristen R.; Watson, Tanya T.; Lee, Daniel W., III

2004-01-01

Microscale fusions, description, and spectroscopic analysis of the reactivity of a square planar Cu(III) complex significant to green chemistry, are presented. The experiment also includes nine focal points on which pre-lab and post-lab questions are based, and the final exams reflect the students' comprehension of these and other features of…

2008 Annual Report

DTIC Science & Technology

2008-01-01

sensors. We will engineer a collection of protein-based switches that are capable of dynamically responding to our desired end-product D-BT over a...locations in the cells; (2) enables control over the molecular ratios of pathway enzymes; and (3) minimizes metabolic cross-talk and side reactions by...pathway enzymes into either static or dynamic channels will be performed by: (1) construction of fusion proteins (static); (2) post-translational protein

Z-Pinch Magneto-Inertial Fusion Propulsion Engine Design Concept

NASA Technical Reports Server (NTRS)

Miernik, Janie H.; Statham, Geoffrey; Adams, Robert B.; Polsgrove, Tara; Fincher, Sharon; Fabisinski, Leo; Maples, C. Dauphne; Percy, Thomas K.; Cortez, Ross J.; Cassibry, Jason

2011-01-01

Fusion-based nuclear propulsion has the potential to enable fast interplanetary transportation. Due to the great distances between the planets of our solar system and the harmful radiation environment of interplanetary space, high specific impulse (Isp) propulsion in vehicles with high payload mass fractions must be developed to provide practical and safe vehicles for human spaceflight missions. Magneto-Inertial Fusion (MIF) is an approach which has been shown to potentially lead to a low cost, small fusion reactor/engine assembly (1). The Z-Pinch dense plasma focus method is an MIF concept in which a column of gas is compressed to thermonuclear conditions by an estimated axial current of approximately 100 MA. Recent advancements in experiments and the theoretical understanding of this concept suggest favorable scaling of fusion power output yield as I(sup 4) (2). The magnetic field resulting from the large current compresses the plasma to fusion conditions, and this is repeated over short timescales (10(exp -6) sec). This plasma formation is widely used in the field of Nuclear Weapons Effects (NWE) testing in the defense industry, as well as in fusion energy research. There is a wealth of literature characterizing Z-Pinch physics and existing models (3-5). In order to be useful in engineering analysis, a simplified Z-Pinch fusion thermodynamic model was developed to determine the quantity of plasma, plasma temperature, rate of expansion, energy production, etc. to calculate the parameters that characterize a propulsion system. The amount of nuclear fuel per pulse, mixture ratio of the D-T and nozzle liner propellant, and assumptions about the efficiency of the engine, enabled the sizing of the propulsion system and resulted in an estimate of the thrust and Isp of a Z-Pinch fusion propulsion system for the concept vehicle. MIF requires a magnetic nozzle to contain and direct the nuclear pulses, as well as a robust structure and radiation shielding. The structure, configuration, and materials of the nozzle must meet many severe requirements. The configuration would focus, in a conical manner, the Deuterium-Tritium (D-T) fuel and Lithium-6/7 liner fluid to meet at a specific point that acts as a cathode so the Li-6 can serve as a current return path to complete the circuit. In addition to serving as a current return path, the Li liner also serves as a radiation shield. The advantage to this configuration is the reaction between neutrons and Li-6 results in the production of additional Tritium, thus adding further fuel to the fusion reaction and boosting the energy output. To understand the applicability of Z-Pinch propulsion to interplanetary travel, it is necessary to design a concept vehicle that uses it. The propulsion system significantly impacts the design of the electrical, thermal control, avionics, radiation shielding, and structural subsystems of a vehicle. The design reference mission is the transport of crew and cargo to Mars and back, with the intention that the vehicle be reused for other missions. Several aspects of this vehicle are based on a previous crewed fusion vehicle study called Human Outer Planet Exploration (HOPE), which employed a Magnetized Target Fusion (MTF) propulsion concept. Analysis of this propulsion system concludes that a 40-fold increase of Isp over chemical propulsion is predicted. This along with a greater than 30% predicted payload mass fraction certainly warrants further development of enabling technologies. The vehicle is designed for multiple interplanetary missions and conceivably may be suited for an automated one-way interstellar voyage.

Pulse-density modulation control of chemical oscillation far from equilibrium in a droplet open-reactor system

PubMed Central

Sugiura, Haruka; Ito, Manami; Okuaki, Tomoya; Mori, Yoshihito; Kitahata, Hiroyuki; Takinoue, Masahiro

2016-01-01

The design, construction and control of artificial self-organized systems modelled on dynamical behaviours of living systems are important issues in biologically inspired engineering. Such systems are usually based on complex reaction dynamics far from equilibrium; therefore, the control of non-equilibrium conditions is required. Here we report a droplet open-reactor system, based on droplet fusion and fission, that achieves dynamical control over chemical fluxes into/out of the reactor for chemical reactions far from equilibrium. We mathematically reveal that the control mechanism is formulated as pulse-density modulation control of the fusion–fission timing. We produce the droplet open-reactor system using microfluidic technologies and then perform external control and autonomous feedback control over autocatalytic chemical oscillation reactions far from equilibrium. We believe that this system will be valuable for the dynamical control over self-organized phenomena far from equilibrium in chemical and biomedical studies. PMID:26786848

An overview of the development of the first wall and other principal components of a laser fusion power plant

NASA Astrophysics Data System (ADS)

Sethian, John D.; Raffray, A. Rene; Latkowski, Jeffery; Blanchard, James P.; Snead, Lance; Renk, Timothy J.; Sharafat, Shahram

2005-12-01

This paper introduces the JNM Special Issue on the development of a first wall for the reaction chamber in a laser fusion power plant. In this approach to fusion energy a spherical target is injected into a large chamber and heated to fusion burn by an array of lasers. The target emissions are absorbed by the wall and encapsulating blanket, and the resulting heat converted into electricity. The bulk of the energy deposited in the first wall is in the form of X-rays (1.0-100 keV) and ions (0.1-4 MeV). In order to have a practical power plant, the first wall must be resistant to these emissions and suffer virtually no erosion on each shot. A wall candidate based on tungsten armor bonded to a low activation ferritic steel substrate has been chosen as the initial system to be studied. The choice was based on the vast experience with these materials in a nuclear environment and the ability to address most of the key remaining issues with existing facilities. This overview paper is divided into three parts. The first part summarizes the current state of the development of laser fusion energy. The second part introduces the tungsten armored ferritic steel concept, the three critical development issues (thermo-mechanical fatigue, helium retention, and bonding) and the research to address them. Based on progress to date the latter two appear to be resolvable, but the former remains a challenge. Complete details are presented in the companion papers in this JNM Special Issue. The third part discusses other factors that must be considered in the design of the first wall, including compatibility with blanket concepts, radiological concerns, and structural considerations.

Condensed Matter Nuclear Science

NASA Astrophysics Data System (ADS)

Takahashi, Akito; Ota, Ken-Ichiro; Iwamura, Yashuhiro

Preface -- 1. General. Progress in condensed matter nuclear science / A. Takahashi. Summary of ICCF-12 / X. Z. Li. Overview of light water/hydrogen-based low-energy nuclear reactions / G. H. Miley and P. J. Shrestha -- 2. Excess heat and He detection. Development of "DS-reactor" as the practical reactor of "cold fusion" based on the "DS-cell" with "DS-cathode" / Y. Arata and Y.-C. Zhang. Progress in excess of power experiments with electrochemical loading of deuterium in palladium / V. Violante ... [et al.]. Anomalous energy generation during conventional electrolysis / T. Mizuno and Y. Toriyabe. "Excess heat" induced by deuterium flux in palladium film / B. Liu ... [et al.]. Abnormal excess heat observed during Mizuno-type experiments / J.-F. Fauvarque, P. P. Clauzon and G. J.-M. Lallevé. Seebeck envelope calorimetry with a Pd|D[symbol]O + H[symbol]SO[symbol] electrolytic cell / W.-S. Zhang, J. Dash and Q. Wang. Observation and investigation of nuclear fusion and self-induced electric discharges in liquids / A. I. Koldamasov ... [et al.]. Description of a sensitive seebeck calorimeter used for cold fusion studies / E. Storms. Some recent results at ENEA / M. Apicella ... [et al.]. Heat measurement during plasma electrolysis / K. Iizumi ... [et al.]. Effect of an additive on thermal output during electrolysis of heavy water with a palladium cathode / Q. Wang and J. Dash. Thermal analysis of calorimetric systems / L. D'Aulerio ... [et al.]. Surface plasmons and low-energy nuclear reactions triggering / E. Castagna ... [et al.]. Production method for violent TCB jet plasma from cavity / F. Amini. New results and an ongoing excess heat controversy / L. Kowalski ... [et al.] -- 3. Transmutation. Observation of surface distribution of products by X-ray fluorescence spectrometry during D[symbol] gas permeation through Pd Complexes / Y. Iwamura ... [et al.]. Discharge experiment using Pd/CaO/Pd multi-layered cathode / S. Narita ... [et al.]. Producing transmutation element on multi-layered Pd sample by deuterium permeation / H. Yamada ... [et al.]. Experimental observation and combined investigation of high-performance fusion of iron-region isotopes in optimal growing microbiological associations / V. I. Vysotskii ... [et al.]. Research into low-energy nuclear reactions in cathode sample solid with production of excess heat, stable and radioactive impurity nuclides / A. B. Karabut. Influence of parameters of the glow discharge on change of structure and the isotope composition of the cathode materials / I. B. Savvatimova and D. V. Gavritenkov. Elemental analysis of palladium electrodes after Pd/Pd light water critical electrolysis / Y. Toriyabe ... [et al.]. Progress on the study of isotopic composition in metallic thin films undergone to electrochemical loading of hydrogen / M. Apicella ... [et al.]. In situ accelerator analyses of palladium complex under deuterium permeation / A. Kitamura ... [et al.]. High-resolution mass spectrum for deuterium (hydrogen) gas permeating palladium film / Q. M. Wei ... [et al.]. ICP-MS analysis of electrodes and electrolytes after HNO[symbol]/H[symbol]O electrolysis / S. Taniguchi ... [et al.]. The Italy-Japan project - fundamental research on cold transmutation process for treatment of nuclear wastes / A. Takahashi, F. Celani and Y. Iwamura -- 4. Nuclear physics approach. Reproducible nuclear emissions from Pd/PdO:Dx heterostructure during controlled exothermic deuterium desorption / A. G. Lipson ... [et al.]. Correct identification of energetic alpha and proton tracks in experiments on CR-39 charged particle detection during hydrogen desorption from Pd/PdO:H[symbol] heterostructure / A. S. Roussetski ... [et al.]. Intense non-linear soft X-ray emission from a hydride target during pulsed D bombardment / G. H. Miley ... [et al.]. Enhancement of first wall damage in ITER type TOKAMAK due to LENR effects / A. G. Lipson, G. H. Miley and H. Momota. Generation of DD-reactions in a ferroelectric KD[symbol]PO[symbol] single crystal during transition through curie point (Tc = 220K) / A. G. Lipson ... [et al.]. Study of energetic and temporal characteristics of X-ray emission from solid-state cathode medium of high-current glow discharge / A. B. Karabut. A novel LiF-based detector for X-ray imaging in hydrogen loaded Ni films under laser irradiation / R. M. Montereali ... [et al.]. Observation and modeling of the ordered motion of hypothetical magnetically charged particles on the multilayer surface and the problem of low-energy fusion / S. V. Adamenko and V. I. Vysotskii -- 5. Material science. Evidence of superstoichiometric H/D lenr active sites and high-temperature superconductivity in a hydrogen-cycled Pd/PdO / A. G. Lipson ... [et al.]. New procedures to make active, fractal-like surfaces on thin Pd wires / F. Celani ... [et al.]. Using resistivity to measure H/Pd and D/Pd loading: Method and significance / M. C. H. McKubre and F. L. Tanzella. Measurements of the temperature coefficient of electric resistivity of hydrogen overloaded Pd / A. Spallone ... [et al.]. Magnetic interaction of hypothetical particles moving beneath the electrode/electrolyte interface to elucidate evolution mechanism of vortex appeared on Pd surface after long-term evolution of deuterium in 0.1 m LiOD / H. Numata and M. Ban. Unusual structures on the material surfaces irradiated by low-energy ions / B. Rodionov and I. Savvatimova -- 6. Theory. Context for understanding why particular nanoscale crystals turn-on faster and other LENR effects / S. R. Chubb. Models for anomalies in condensed matter deuterides / P. L. Hagelstein. Time-dependent EQPET analysis of TSC / A. Takahashi. Unifying theory of low-energy nuclear reaction and transmutation processes in deuterated/hydrogenated metals, acoustic cavitation, glow discharge, and deuteron beam experiments / Y. E. Kim and A. L. Zubarev. Catalytic fusion and the interface between insulators and transition metals / T. A. Chubb. Multiple scattering of deuterium wave function near surface of palladium lattice / X. Z. Li ... [et al.]. Theoretical comparison between semi-classical and quantum tunneling effect / F. Frisone. New cooperative mechanisms of low-energy nuclear reactions using super low-energy external field / F. A. Gareev and I. E. Zhidkova. Polyneutron theory of transmutation / J. C. Fisher. The thermal conduction from the centers of the nuclear reactions in solids / K.-I. Tsuchiya. Four-body RST general nuclear wavefunctions and matrix elements / I. Chaudhary and P. L. Hagelstein. Study on formation of tetrahedral or octahedral symmetric condensation by hopping of alkali or alkaline-earth metal ion / H. Miura. Calculations of nuclear reactions probability in a crystal lattice of lanthanum deuteride / V. A. Kirkinskii and Yu. A. Novikov. Possible coupled electron and electron neutrino in nucleus and its physical catalysis effect on D-D cold fusion into helium in Pd / M. Fukuhara. Tunnel resonance of electron wave and force of fluctuation / M. Ban. Types of nuclear fusion in solids / N. Yabuuchi. Neutrino-dineutron reactions (low-energy nuclear reactions induced by D[symbol] gas permeation through Pd complexes - Y. Iwamura effect) / V. Muromtsev, V. Platonov and I. Savvatimova. An explanation of earthquakes by the blacklight process and hydrogen fusion / H. Yamamoto. Theoretical modeling of electron flow action on probability of nuclear fusion of deuterons / A. I. Goncharov and V. A. Kirkinskii.

Efficient Fabrication of Nanoporous Si and Si/Ge Enabled by a Heat Scavenger in Magnesiothermic Reactions

PubMed Central

Luo, Wei; Wang, Xingfeng; Meyers, Colin; Wannenmacher, Nick; Sirisaksoontorn, Weekit; Lerner, Michael M.; Ji, Xiulei

2013-01-01

Magnesiothermic reduction can directly convert SiO2 into Si nanostructures. Despite intense efforts, efficient fabrication of highly nanoporous silicon by Mg still remains a significant challenge due to the exothermic reaction nature. By employing table salt (NaCl) as a heat scavenger for the magnesiothermic reduction, we demonstrate an effective route to convert diatom (SiO2) and SiO2/GeO2 into nanoporous Si and Si/Ge composite, respectively. Fusion of NaCl during the reaction consumes a large amount of heat that otherwise collapses the nano-porosity of products and agglomerates silicon domains into large crystals. Our methodology is potentially competitive for a practical production of nanoporous Si-based materials. PMID:23860418

Efficient fabrication of nanoporous si and Si/Ge enabled by a heat scavenger in magnesiothermic reactions.

PubMed

Luo, Wei; Wang, Xingfeng; Meyers, Colin; Wannenmacher, Nick; Sirisaksoontorn, Weekit; Lerner, Michael M; Ji, Xiulei

2013-01-01

Magnesiothermic reduction can directly convert SiO2 into Si nanostructures. Despite intense efforts, efficient fabrication of highly nanoporous silicon by Mg still remains a significant challenge due to the exothermic reaction nature. By employing table salt (NaCl) as a heat scavenger for the magnesiothermic reduction, we demonstrate an effective route to convert diatom (SiO2) and SiO2/GeO2 into nanoporous Si and Si/Ge composite, respectively. Fusion of NaCl during the reaction consumes a large amount of heat that otherwise collapses the nano-porosity of products and agglomerates silicon domains into large crystals. Our methodology is potentially competitive for a practical production of nanoporous Si-based materials.

Dynamics of 28,30S i* compound nuclei formed at sub-barrier energies

NASA Astrophysics Data System (ADS)

Kaur, Manpreet; Singh, Bir Bikram; Kaur, Sarbjeet

2018-05-01

The decay of 28S i* and 30S i* compound nuclei (CN) formed at sub-barrier energies, in the reactions induced by stable projectile 16O and exotic projectile 18O, respectively, has been investigated within the quantum mechanical fragmentation theory based dynamical cluster-decay model (DCM). The collective potential energy surface shows that xα-type (x is an integer) clusters are minimized in the decay of 28S i* while in case of 30S i* in addition to xα-type clusters, np-xα (n, p are neutron and proton, respectively) type clusters are also minimized. These minimized fragments have more preformation probability P0, which is an important factor through which nuclear structure effects of decaying CN are probed, within DCM. The results show that light particles (LPs) are contributing mostly in the fusion cross-section, σfusion. In case of 30S i*, the contribution of 1n is highest and more compared to 4He in case of 28S i*, which seems to play an important role in fusion enhancement. The DCM calculated σfusion for both the CN formed with same Ec.m. = 7.0 MeV gives more value for σfusion of 30S i*, in agreement with the experimental data.

Commercial objectives, technology transfer, and systems analysis for fusion power development

NASA Astrophysics Data System (ADS)

Dean, Stephen O.

1988-09-01

Fusion is an inexhaustible source of energy that has the potential for economic commercial applications with excellent safety and environmental characteristics. The primary focus for the fusion energy development program is the generation of central station electricity. Fusion has the potential, however, for many other applications. The fact that a large fraction of the energy released in a DT fusion reaction is carried by high energy neutrons suggests potentially unique applications. In addition, fusion R and D will lead to new products and new markets. Each fusion application must meet certain standards of economic and safety and environmental attractiveness. For this reason, economics on the one hand, and safety and environment and licensing on the other, are the two primary criteria for setting long range commercial fusion objectives. A major function of systems analysis is to evaluate the potential of fusion against these objectives and to help guide the fusion R and D program toward practical applications. The transfer of fusion technology and skills from the national labs and universities to industry is the key to achieving the long range objective of commercial fusion applications.

Commercial objectives, technology transfer, and systems analysis for fusion power development

NASA Technical Reports Server (NTRS)

Dean, Stephen O.

1988-01-01

Fusion is an inexhaustible source of energy that has the potential for economic commercial applications with excellent safety and environmental characteristics. The primary focus for the fusion energy development program is the generation of central station electricity. Fusion has the potential, however, for many other applications. The fact that a large fraction of the energy released in a DT fusion reaction is carried by high energy neutrons suggests potentially unique applications. In addition, fusion R and D will lead to new products and new markets. Each fusion application must meet certain standards of economic and safety and environmental attractiveness. For this reason, economics on the one hand, and safety and environment and licensing on the other, are the two primary criteria for setting long range commercial fusion objectives. A major function of systems analysis is to evaluate the potential of fusion against these objectives and to help guide the fusion R and D program toward practical applications. The transfer of fusion technology and skills from the national labs and universities to industry is the key to achieving the long range objective of commercial fusion applications.

HIP1-ALK, a novel fusion protein identified in lung adenocarcinoma.

PubMed

Hong, Mineui; Kim, Ryong Nam; Song, Ji-Young; Choi, So-Jung; Oh, Ensel; Lira, Maruja E; Mao, Mao; Takeuchi, Kengo; Han, Joungho; Kim, Jhingook; Choi, Yoon-La

2014-03-01

The most common mechanism underlying overexpression and activation of anaplastic lymphoma kinase (ALK) in non-small-cell lung carcinoma could be attributed to the formation of a fusion protein. To date, five fusion partners of ALK have been reported, namely, echinoderm microtubule associated protein like 4, tropomyosin-related kinase-fused gene, kinesin family member 5B, kinesin light chain 1, and protein tyrosine phosphatase, nonreceptor type 3. In this article, we report a novel fusion gene huntingtin interacting protein 1 (HIP1)-ALK, which is conjoined between the huntingtin-interacting protein 1 gene HIP1 and ALK. Reverse-transcriptase polymerase chain reaction and immunohistochemical analysis were used to detect this fusion gene's transcript and protein expression, respectively. We had amplified the full-length cDNA sequence of this novel fusion gene by using 5'-rapid amplification of cDNA ends. The causative genomic translocation t(2;7)(p23;q11.23) for generating this novel fusion gene was verified by using genomic sequencing. The examined adenocarcinoma showed predominant acinar pattern, and ALK immunostaining was localized to the cytoplasm, with intense staining in the submembrane region. In break-apart, fluorescence in situ hybridization analysis for ALK, split of the 5' and 3' probe signals, and isolated 3' signals were observed. Reverse-transcriptase polymerase chain reaction revealed that the tumor harbored a novel fusion transcript in which exon 21 of HIP1 was fused to exon 20 of ALK in-frame. The novel fusion gene and its protein HIP1-ALK harboring epsin N-terminal homology, coiled-coil, juxtamembrane, and kinase domains, which could play a role in carcinogenesis, could become diagnostic and therapeutic target of the lung adenocarcinoma and deserve a further study in the future.

Fusion and quasifission studies for the 40Ca+186W,192Os reactions

NASA Astrophysics Data System (ADS)

Prasad, E.; Hinde, D. J.; Williams, E.; Dasgupta, M.; Carter, I. P.; Cook, K. J.; Jeung, D. Y.; Luong, D. H.; Palshetkar, C. S.; Rafferty, D. C.; Ramachandran, K.; Simenel, C.; Wakhle, A.

2017-09-01

Background: All elements above atomic number 113 have been synthesized using hot fusion reactions with calcium beams on statically deformed actinide target nuclei. Quasifission and fusion-fission are the two major mechanisms responsible for the very low production cross sections of superheavy elements. Purpose: To achieve a quantitative measurement of capture and quasifission characteristics as a function of beam energy in reactions forming heavy compound systems using calcium beams as projectiles. Methods: Fission fragment mass-angle distributions were measured for the two reactions 40Ca+186W and 40C+192Os, populating 226Pu and 232Cm compound nuclei, respectively, using the Heavy Ion Accelerator Facility and CUBE spectrometer at the Australian National University. Mass ratio distributions, angular distributions, and total fission cross sections were obtained from the experimental data. Simulations to match the features of the experimental mass-angle distributions were performed using a classical phenomenological approach. Results: Both 40Ca+186W and 40C+192Os reactions show strong mass-angle correlations at all energies measured. A maximum fusion probability of 60 -70 % is estimated for the two reactions in the energy range of the present study. Coupled-channels calculations assuming standard Woods-Saxon potential parameters overpredict the capture cross sections. Large nuclear potential diffuseness parameters ˜1.5 fm are required to fit the total capture cross sections. The presence of a weak mass-asymmetric quasifission component attributed to the higher angular momentum events can be reproduced with a shorter average sticking time but longer mass-equilibration time constant. Conclusions: The deduced above-barrier capture cross sections suggest that the dissipative processes are already occurring outside the capture barrier. The mass-angle correlations indicate that a compact shape is not achieved for deformation aligned collisions with lower capture barriers. The average sticking time of fast quasifission events is 10-20 s.

Study of near-stability nuclei populated as fission fragments in heavy-ion fusion reactions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fotiadis, Nikolaos; Nelson, Ronald O; Devlin, Matthew

2010-01-01

Examples are presented to illustrate the power of prompt {gamma}-ray spectroscopy of fission fragments from compound nuclei with A {approx} 200 formed in fusion-evaporation reactions in experiments using the Gammasphere Ge-detector array. Complementary methods, such as Coulomb excitation and deep-inelastic processes, are also discussed. In other cases (n, xn{gamma}) reactions on stable isotopes have been used to establish neutron excitation functions for {gamma}-rays using a pulsed 'white'-neutron source, coupled to a high-energy-resolution germanium-detector array. The excitation functions can unambiguously assign {gamma}-rays to a specific reaction product. Results from all these methods bridge the gaps in the systematics of high-spin statesmore » between the neutron-deficient and neutron-rich nuclei. Results near shell closures should motivate new shell model calculations.« less

Use of Helium Production to Screen Glow Discharges for Low Energy Nuclear Reactions (LENR)

NASA Astrophysics Data System (ADS)

Passell, Thomas O.

2011-03-01

My working hypothesis of the conditions required to observe low energy nuclear reactions (LENR) follows: 1) High fluxes of deuterium atoms through interfaces of grains of metals that readily accommodate movement of hydrogen atoms interstitially is the driving variable that produces the widely observed episodes of excess heat above the total of all input energy. 2) This deuterium atom flux has been most often achieved at high electrochemical current densities on highly deuterium-loaded palladium cathodes but is clearly possible in other experimental arrangements in which the metal is interfacing gaseous deuterium, as in an electrical glow discharge. 3) Since the excess heat episodes must be producing the product(s) of some nuclear fusion reaction(s) screening of options may be easier with measurement of those ``ashes'' than the observance of the excess heat. 4) All but a few of the exothermic fusion reactions known among the first 5 elements produce He-4. Hence helium-4 appearance in an experiment may be the most efficient indicator of some fusion reaction without commitment on which reaction is occurring. This set of hypotheses led me to produce a series of sealed tubes of wire electrodes of metals known to absorb hydrogen and operate them for 100 days at the 1 watt power level using deuterium gas pressures of ~ 100 torr powered by 40 Khz AC power supplies. Observation of helium will be by measurement of helium optical emission lines through the glass envelope surrounding the discharge. The results of the first 18 months of this effort will be described.

Dynamics of Db isotopes formed in reactions induced by 238U, 248Cm, and 249Bk across the Coulomb barrier

NASA Astrophysics Data System (ADS)

Kaur, Gurjit; Sandhu, Kirandeep; Kaur, Amandeep; Sharma, Manoj K.

2018-05-01

The dynamical cluster decay model is employed to investigate the decay of *265Db and *267Db nuclei, formed in the 27Al+238U , 18O+249Bk , and 19F+248Cm hot fusion reactions at energies around the Coulomb barrier. First, the fission dynamics of the 27Al+238U reaction is explored by investigating the fragmentation and preformation yield of the reaction. The symmetric mass distribution of the fission fragments is observed for *265Db nucleus, when static β2 i deformations are used within hot optimum orientation approach. However, the mass split gets broaden for the use of β2 i-dynamical hot configuration of the fragments and becomes clearly asymmetric for the cold-static-deformed approach. Within the application of cold orientations of fragments, a new fission channel is observed at mass asymmetry η =0.29 . In addition to 238U-induced reaction, the work is carried out to address the fission and neutron evaporation cross sections of *267Db nucleus formed via 19F+248Cm and 18O+249Bk reactions, besides a comprehensive analysis of fusion and capture processes. Higher fusion cross sections and compound nucleus formation probabilities (PCN) are obtained for the 18O+249Bk reaction, as larger mass asymmetry in the entrance channel leads to reduced Coulomb factor. Finally, the role of sticking (IS) and nonsticking (INS) moments of inertia is analyzed for the 4 n and 5 n channels of *267Db nuclear system.

A DNA-based semantic fusion model for remote sensing data.

PubMed

Sun, Heng; Weng, Jian; Yu, Guangchuang; Massawe, Richard H

2013-01-01

Semantic technology plays a key role in various domains, from conversation understanding to algorithm analysis. As the most efficient semantic tool, ontology can represent, process and manage the widespread knowledge. Nowadays, many researchers use ontology to collect and organize data's semantic information in order to maximize research productivity. In this paper, we firstly describe our work on the development of a remote sensing data ontology, with a primary focus on semantic fusion-driven research for big data. Our ontology is made up of 1,264 concepts and 2,030 semantic relationships. However, the growth of big data is straining the capacities of current semantic fusion and reasoning practices. Considering the massive parallelism of DNA strands, we propose a novel DNA-based semantic fusion model. In this model, a parallel strategy is developed to encode the semantic information in DNA for a large volume of remote sensing data. The semantic information is read in a parallel and bit-wise manner and an individual bit is converted to a base. By doing so, a considerable amount of conversion time can be saved, i.e., the cluster-based multi-processes program can reduce the conversion time from 81,536 seconds to 4,937 seconds for 4.34 GB source data files. Moreover, the size of result file recording DNA sequences is 54.51 GB for parallel C program compared with 57.89 GB for sequential Perl. This shows that our parallel method can also reduce the DNA synthesis cost. In addition, data types are encoded in our model, which is a basis for building type system in our future DNA computer. Finally, we describe theoretically an algorithm for DNA-based semantic fusion. This algorithm enables the process of integration of the knowledge from disparate remote sensing data sources into a consistent, accurate, and complete representation. This process depends solely on ligation reaction and screening operations instead of the ontology.

A DNA-Based Semantic Fusion Model for Remote Sensing Data

PubMed Central

Sun, Heng; Weng, Jian; Yu, Guangchuang; Massawe, Richard H.

2013-01-01

Semantic technology plays a key role in various domains, from conversation understanding to algorithm analysis. As the most efficient semantic tool, ontology can represent, process and manage the widespread knowledge. Nowadays, many researchers use ontology to collect and organize data's semantic information in order to maximize research productivity. In this paper, we firstly describe our work on the development of a remote sensing data ontology, with a primary focus on semantic fusion-driven research for big data. Our ontology is made up of 1,264 concepts and 2,030 semantic relationships. However, the growth of big data is straining the capacities of current semantic fusion and reasoning practices. Considering the massive parallelism of DNA strands, we propose a novel DNA-based semantic fusion model. In this model, a parallel strategy is developed to encode the semantic information in DNA for a large volume of remote sensing data. The semantic information is read in a parallel and bit-wise manner and an individual bit is converted to a base. By doing so, a considerable amount of conversion time can be saved, i.e., the cluster-based multi-processes program can reduce the conversion time from 81,536 seconds to 4,937 seconds for 4.34 GB source data files. Moreover, the size of result file recording DNA sequences is 54.51 GB for parallel C program compared with 57.89 GB for sequential Perl. This shows that our parallel method can also reduce the DNA synthesis cost. In addition, data types are encoded in our model, which is a basis for building type system in our future DNA computer. Finally, we describe theoretically an algorithm for DNA-based semantic fusion. This algorithm enables the process of integration of the knowledge from disparate remote sensing data sources into a consistent, accurate, and complete representation. This process depends solely on ligation reaction and screening operations instead of the ontology. PMID:24116207

Prevalence of Abelson murine leukemia viral oncogene homolog-breakpoint cluster region fusions and correlation with peripheral blood parameters in chronic myelogenous leukemia patients in Lorestan Province, Iran.

PubMed

Kiani, Ali Asghar; Shahsavar, Farhad; Gorji, Mojtaba; Ahmadi, Kolsoum; Nazarabad, Vahideh Heydari; Bahmani, Banafsheh

2016-01-01

Chronic myelogenous leukemia (CML) is a chronic malignancy of myeloid linage associated with a significant increase in granulocytes in bone marrow and peripheral blood. CML diagnosis is based on detection of Philadelphia chromosome and "Abelson murine leukemia viral oncogene homolog" (ABL)-"breakpoint cluster region protein" fusions (ABL-BCR fusions). In this study, patients with CML morphology were studied according to ABL-BCR fusions and the relationship between the fusions and peripheral blood cell changes was examined. All patients suspected to chronic myeloproliferative disorders in Lorestan Province visiting subspecialist hematology clinics who were confirmed by oncologist were studied over a period of 5 years. After completing basic data questionnaire, blood samples were obtained with informed consent from the patients. Blood cell count and morphology were investigated and RNA was extracted from blood samples. cDNA was synthesized from RNA and ABL-BCR fusions including b3a2 and b2a2 (protein 210 kd or p210), e1a2 (protein 190 kdor p190), and e19a2 (protein 230 kdor p230) were studied by multiplex reverse transcription polymerase chain reaction method. Coexistence of e1a2 and b2a2 (p210/p190) fusions was also studied. The prevalence of mutations and their correlation with the blood parameters were statistically analyzed. Of 58 patients positive for ABL-BCR fusion, 18 (30.5%) had b2a2 fusion, 37 (62.71%) had b3a2 fusion and three (3.08%) had e1a2 fusion. Coexistence of e1a2 and b2a2 (p210/p190) was not observed. There was no significant correlation between ABL-BCR fusions and white blood cell count, platelet count, and hemoglobin concentration. The ABL-BCR fusions in Lorestan Province were similar to other studies in Iran, and b3a2 fusion had the highest prevalence in the studied patients studied.

Safety and Environment aspects of Tokamak- type Fusion Power Reactor- An Overview

NASA Astrophysics Data System (ADS)

Doshi, Bharat; Reddy, D. Chenna

2017-04-01

Naturally occurring thermonuclear fusion reaction (of light atoms to form a heavier nucleus) in the sun and every star in the universe, releases incredible amounts of energy. Demonstrating the controlled and sustained reaction of deuterium-tritium plasma should enable the development of fusion as an energy source here on Earth. The promising fusion power reactors could be operated on the deuterium-tritium fuel cycle with fuel self-sufficiency. The potential impact of fusion power on the environment and the possible risks associated with operating large-scale fusion power plants is being studied by different countries. The results show that fusion can be a very safe and sustainable energy source. A fusion power plant possesses not only intrinsic advantages with respect to safety compared to other sources of energy, but also a negligible long term impact on the environment provided certain precautions are taken in its design. One of the important considerations is in the selection of low activation structural materials for reactor vessel. Selection of the materials for first wall and breeding blanket components is also important from safety issues. It is possible to fully benefit from the advantages of fusion energy if safety and environmental concerns are taken into account when considering the conceptual studies of a reactor design. The significant safety hazards are due to the tritium inventory and energetic neutron fluence induced activity in the reactor vessel, first wall components, blanket system etc. The potential of release of radioactivity under operational and accident conditions needs attention while designing the fusion reactor. Appropriate safety analysis for the quantification of the risk shall be done following different methods such as FFMEA (Functional Failure Modes and Effects Analysis) and HAZOP (Hazards and operability). Level of safety and safety classification such as nuclear safety and non-nuclear safety is very important for the FPR (Fusion Power Reactor). This paper describes an overview of safety and environmental merits of fusion power reactor, issues and design considerations and need for R&D on safety and environmental aspects of Tokamak type fusion reactor.

Dependence of Fusion Barrier Heights on the Difference of Proton and Neutron Radii

NASA Astrophysics Data System (ADS)

Dobrowolski, A.; Pomorski, K.; Bartel, J.

2005-04-01

Using the Skyrme effective nucleon--nucleon interaction together with the semiclassical Extended Thomas--Fermi approach (ETF) we investigate the relative change of the fusion barrier heights for the reaction 16O+208Pb as function of the nuclear proton or neutron radii of the colliding nuclei.

What perspectives for the synthesis of heavier superheavy nuclei? Results and comparison with models

NASA Astrophysics Data System (ADS)

Mandaglio, G.; Nasirov, A. K.; Curciarello, F.; De Leo, V.; Romaniuk, M.; Fazio, G.; Giardina, G.

2013-03-01

The possibility to synthesize heavier superheavy elements in massive nuclei reactions is strongly limited by the hindrance to complete fusion of reacting nuclei: due to the onset of the quasifission process in the entrance channel, which competes with complete fusion, and by strong increase of the fission yield along the de-excitation cascade of the compound nucleus in comparison to the evaporation residue formation. We present a wide and detailed procedure allowing us to describe the experimental results (evaporation residue nuclei and fissionlike products) in the mass asymmetric and symmetric reactions. Very reliable estimations and perspectives for the synthesis of superheavy elements in many massive nuclei reactions up to Z = 120 and eventually also for Z > 120 have been obtained.

Simultaneous measurement of the HT and DT fusion burn histories in inertial fusion implosions

DOE PAGES

Zylstra, Alex B.; Herrmann, Hans W.; Kim, Yong Ho; ...

2017-05-23

Measuring the thermonuclear burn history is an important way to diagnose inertial fusion implosions. Here, using the gas Cherenkov detectors at the OMEGA laser facility, we measure the HT fusion burn in a H 2+T 2 gas-fueled implosion for the first time. Then, using multiple detectors with varied Cherenkov thresholds, we demonstrate a technique for simultaneously measuring both the HT and DT burn histories from an implosion where the total reaction yields are comparable. This new technique will be used to study material mixing and kinetic phenomena in implosions.

Probing the fusion of neutron-rich nuclei with re-accelerated radioactive beams

NASA Astrophysics Data System (ADS)

Vadas, J.; Singh, Varinderjit; Wiggins, B. B.; Huston, J.; Hudan, S.; deSouza, R. T.; Lin, Z.; Horowitz, C. J.; Chbihi, A.; Ackermann, D.; Famiano, M.; Brown, K. W.

2018-03-01

We report the first measurement of the fusion excitation functions for K,4739+28Si at near-barrier energies. Evaporation residues resulting from the fusion process were identified by direct measurement of their energy and time of flight with high geometric efficiency. At the lowest incident energy, the cross section measured for the neutron-rich 47K-induced reaction is ≈6 times larger than that of the β -stable system. This experimental approach, both in measurement and in analysis, demonstrates how to efficiently measure fusion with low-intensity re-accelerated radioactive beams, establishing the framework for future studies.

Simultaneous measurement of the HT and DT fusion burn histories in inertial fusion implosions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zylstra, Alex B.; Herrmann, Hans W.; Kim, Yong Ho

Measuring the thermonuclear burn history is an important way to diagnose inertial fusion implosions. Here, using the gas Cherenkov detectors at the OMEGA laser facility, we measure the HT fusion burn in a H 2+T 2 gas-fueled implosion for the first time. Then, using multiple detectors with varied Cherenkov thresholds, we demonstrate a technique for simultaneously measuring both the HT and DT burn histories from an implosion where the total reaction yields are comparable. This new technique will be used to study material mixing and kinetic phenomena in implosions.

Quantifying Fusion Born Ion Populations in Magnetically Confined Plasmas using Ion Cyclotron Emission

NASA Astrophysics Data System (ADS)

Carbajal, L.; Dendy, R. O.; Chapman, S. C.; Cook, J. W. S.

2017-03-01

Ion cyclotron emission (ICE) offers a unique promise as a diagnostic of the fusion born alpha-particle population in magnetically confined plasmas. Pioneering observations from JET and TFTR found that ICE intensity PICE scales approximately linearly with the measured neutron flux from fusion reactions, and with the inferred concentration, nα/ni, of fusion born alpha particles confined within the plasma. We present fully nonlinear self-consistent kinetic simulations that reproduce this scaling for the first time. This resolves a long-standing question in the physics of fusion alpha-particle confinement and stability in magnetic confinement fusion plasmas. It confirms the magnetoacoustic cyclotron instability as the likely emission mechanism and greatly strengthens the basis for diagnostic exploitation of ICE in future burning plasmas.

Quantifying Fusion Born Ion Populations in Magnetically Confined Plasmas using Ion Cyclotron Emission.

PubMed

Carbajal, L; Dendy, R O; Chapman, S C; Cook, J W S

2017-03-10

Ion cyclotron emission (ICE) offers a unique promise as a diagnostic of the fusion born alpha-particle population in magnetically confined plasmas. Pioneering observations from JET and TFTR found that ICE intensity P_{ICE} scales approximately linearly with the measured neutron flux from fusion reactions, and with the inferred concentration, n_{α}/n_{i}, of fusion born alpha particles confined within the plasma. We present fully nonlinear self-consistent kinetic simulations that reproduce this scaling for the first time. This resolves a long-standing question in the physics of fusion alpha-particle confinement and stability in magnetic confinement fusion plasmas. It confirms the magnetoacoustic cyclotron instability as the likely emission mechanism and greatly strengthens the basis for diagnostic exploitation of ICE in future burning plasmas.

Using secondary nuclear products for inferring the fuel areal density, convergence, and electron temperatures of deuterium filled implosions on the NIF

NASA Astrophysics Data System (ADS)

Lahmann, B.; Frenje, J. A.; Gatu Johnson, M.; Sio, H.; Kabadi, N. V.; Sutcliffe, G.; Seguin, F. H.; Li, C. K.; Petrasso, R. D.; Hartouni, E. P.; Rinderknecht, H. G.; Sayre, D. B.; Yeamans, C. B.; Khan, S. F.; Kyrala, G. A.; Lepape, S.; Berzak-Hopkins, L.; Meezan, N.; Bionta, R.; Ma, T.

2016-10-01

In deuterium-filled inertial confinement fusion implosions, 0.82 MeV 3He and 1.01 MeV T born from the primary DD reaction branches can undergo fusion reactions with the thermal deuterium plasma to create secondary D3He protons and DT neutrons respectively. In regimes of moderate fuel areal density (ρR 5 - 100 mg/cm2) the ratio of both of these secondary yields to the primary yield can be used to infer the fuel ρR, convergence, and an electron temperature (Te) simultaneously. This technique has been used on a myriad of deuterium filled implosion experiments on the NIF using the nuclear time of flight (NTOF) diagnostics to measure the secondary DT neutrons and CR-39 based wedge range filters (WRFs) to measure the secondary D3He protons. Additionally, a comparative study is conducted between the nuclear inferred convergence and x-ray inferred convergence obtained on these experiments. This work was supported in part by LLE, the U.S. DoE (NNSA, NLUF) and LLNL.

Connecting the Particles in the Box - Controlled Fusion of Hexamer Nanocrystal Clusters within an AB6 Binary Nanocrystal Superlattice

PubMed Central

Treml, Benjamin E.; Lukose, Binit; Clancy, Paulette; Smilgies, Detlef-M; Hanrath, Tobias

2014-01-01

Binary nanocrystal superlattices present unique opportunities to create novel interconnected nanostructures by partial fusion of specific components of the superlattice. Here, we demonstrate the binary AB6 superlattice of PbSe and Fe2O3 nanocrystals as a model system to transform the central hexamer of PbSe nanocrystals into a single fused particle. We present detailed structural analysis of the superlattices by combining high-resolution X-ray scattering and electron microscopy. Molecular dynamics simulations show optimum separation of nanocrystals in agreement with the experiment and provide insights into the molecular configuration of surface ligands. We describe the concept of nanocrystal superlattices as a versatile ‘nanoreactor' to create and study novel materials based on precisely defined size, composition and structure of nanocrystals into a mesostructured cluster. We demonstrate ‘controlled fusion' of nanocrystals in the clusters in reactions initiated by thermal treatment and pulsed laser annealing. PMID:25339169

Perspectives of SiC-Based Ceramic Composites and Their Applications to Fusion Reactors 5.Development of Evaluation and Application Techniques of SiC⁄SiC Composites for Fusion Reactors

NASA Astrophysics Data System (ADS)

Hinoki, Tatsuya

Evaluation techniques and mechanical properties of silicon carbide composites (SiC⁄SiC composites) reinforced with highly crystalline fibers are reviewed for fusion applications. The SiC⁄SiC composites used were fabricated by means of the CVI method. The evaluation includes in-plane tensile strength by in-plane tensile test, transthickness tensile strength by transthickness tensile test and diametral compression test and shear strength by compression test using double-notched specimen. All tests were successfully conducted using small specimens for neutron irradiation experiment. As application technique, the novel tungsten(W) coating technique on SiC is reviewed. The W powder melted by high power lamp in a few seconds and formed coating on SiC. No thick reaction layers of WC and W5Si3, which are formed by the other coating methods, were formed by this method.

Experimental Determination of DT Yield in High Current DD Dense Plasma Focii

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lowe, D. R.; Hagen, E. C.; Meehan, B. T.

2013-06-18

Dense Plasma Focii (DPF), which utilize deuterium gas to produce 2.45 MeV neutrons, may in fact also produce DT fusion neutrons at 14.1 MeV due to the triton production in the DD reaction. If beam-target fusion is the primary producer of fusion neutrons in DPFs, it is possible that ejected tritons from the first pinch will interact with the second pinch, and so forth. The 2 MJ DPF at National Security Technologies’ Losee Road Facility is able to, and has produced, over 1E12 DD neutrons per pulse, allowing an accurate measurement of the DT/DD ratio. The DT/DD ratio was experimentallymore » verified by using the (n,2n) reaction in a large piece of praseodymium metal, which has a threshold reaction of 8 MeV, and is widely used as a DT yield measurement system1. The DT/DD ratio was experimentally determined for over 100 shots, and then compared to independent variables such as tube pressure, number of pinches per shot, total current, pinch current and charge voltage.« less

Frontier of Fusion Research: Path to the Steady State Fusion Reactor by Large Helical Device

NASA Astrophysics Data System (ADS)

Motojima, Osamu

2006-12-01

The ITER, the International Thermonuclear Experimental Reactor, which will be built in Cadarache in France, has finally started this year, 2006. Since the thermal energy produced by fusion reactions divided by the external heating power, i.e., the Q value, will be larger than 10, this is a big step of the fusion research for half a century trying to tame the nuclear fusion for the 6.5 Billion people on the Earth. The source of the Sun's power is lasting steadily and safely for 8 Billion years. As a potentially safe environmentally friendly and economically competitive energy source, fusion should provide a sustainable future energy supply for all mankind for ten thousands of years. At the frontier of fusion research important milestones are recently marked on a long road toward a true prototype fusion reactor. In its own merits, research into harnessing turbulent burning plasmas and thereby controlling fusion reaction, is one of the grand challenges of complex systems science. After a brief overview of a status of world fusion projects, a focus is given on fusion research at the National Institute for Fusion Science (NIFS) in Japan, which is playing a role of the Inter University Institute, the coordinating Center of Excellence for academic fusion research and by the Large Helical Device (LHD), the world's largest superconducting heliotron device, as a National Users' facility. The current status of LHD project is presented focusing on the experimental program and the recent achievements in basic parameters and in steady state operations. Since, its start in a year 1998, a remarkable progress has presently resulted in the temperature of 140 Million degree, the highest density of 500 Thousand Billion/cc with the internal density barrier (IDB) and the highest steady average beta of 4.5% in helical plasma devices and the largest total input energy of 1.6 GJ, in all magnetic confinement fusion devices. Finally, a perspective is given of the ITER Broad Approach program as an integrated part of ITER and Development of Fusion Energy project Agreement. Moreover, the relationship with the NIFS' new parent organization the National Institutes of Natural Sciences and with foreign research institutions is briefly explained.

Calcium-Dependent Rubella Virus Fusion Occurs in Early Endosomes.

PubMed

Dubé, Mathieu; Etienne, Loïc; Fels, Maximilian; Kielian, Margaret

2016-07-15

The E1 membrane protein of rubella virus (RuV) is a class II membrane fusion protein structurally related to the fusion proteins of the alphaviruses, flaviviruses, and phleboviruses. Virus entry is mediated by a low pH-dependent fusion reaction through E1's insertion into the cell membrane and refolding to a stable homotrimer. Unlike the other described class II proteins, RuV E1 contains 2 fusion loops, which complex a metal ion between them by interactions with residues N88 and D136. Insertion of the E1 protein into the target membrane, fusion, and infection require calcium and are blocked by alanine substitution of N88 or D136. Here we addressed the requirements of E1 for calcium binding and the intracellular location of the calcium requirement during virus entry. Our results demonstrated that N88 and D136 are optimally configured to support RuV fusion and are strongly selected for during the virus life cycle. While E1 has some similarities with cellular proteins that bind calcium and anionic lipids, RuV binding to the membrane was independent of anionic lipids. Virus fusion occurred within early endosomes, and chelation of intracellular calcium showed that calcium within the early endosome was required for virus fusion and infection. Calcium triggered the reversible insertion of E1 into the target membrane at neutral pH, but E1 homotrimer formation and fusion required a low pH. Thus, RuV E1, unlike other known class II fusion proteins, has distinct triggers for membrane insertion and fusion protein refolding mediated, respectively, by endosomal calcium and low pH. Rubella virus causes a mild disease of childhood, but infection of pregnant women frequently results in miscarriage or severe birth defects. In spite of an effective vaccine, RuV disease remains a serious problem in many developing countries. RuV infection of host cells involves endocytic uptake and low pH-triggered membrane fusion and is unusual in its requirement for calcium binding by the membrane fusion protein. Here we addressed the mechanism of the calcium requirement and the required location of calcium during virus entry. Both calcium and low pH were essential during the virus fusion reaction, which was shown to occur in the early endosome compartment. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Calcium-Dependent Rubella Virus Fusion Occurs in Early Endosomes

PubMed Central

Dubé, Mathieu; Etienne, Loïc; Fels, Maximilian

2016-01-01

ABSTRACT The E1 membrane protein of rubella virus (RuV) is a class II membrane fusion protein structurally related to the fusion proteins of the alphaviruses, flaviviruses, and phleboviruses. Virus entry is mediated by a low pH-dependent fusion reaction through E1's insertion into the cell membrane and refolding to a stable homotrimer. Unlike the other described class II proteins, RuV E1 contains 2 fusion loops, which complex a metal ion between them by interactions with residues N88 and D136. Insertion of the E1 protein into the target membrane, fusion, and infection require calcium and are blocked by alanine substitution of N88 or D136. Here we addressed the requirements of E1 for calcium binding and the intracellular location of the calcium requirement during virus entry. Our results demonstrated that N88 and D136 are optimally configured to support RuV fusion and are strongly selected for during the virus life cycle. While E1 has some similarities with cellular proteins that bind calcium and anionic lipids, RuV binding to the membrane was independent of anionic lipids. Virus fusion occurred within early endosomes, and chelation of intracellular calcium showed that calcium within the early endosome was required for virus fusion and infection. Calcium triggered the reversible insertion of E1 into the target membrane at neutral pH, but E1 homotrimer formation and fusion required a low pH. Thus, RuV E1, unlike other known class II fusion proteins, has distinct triggers for membrane insertion and fusion protein refolding mediated, respectively, by endosomal calcium and low pH. IMPORTANCE Rubella virus causes a mild disease of childhood, but infection of pregnant women frequently results in miscarriage or severe birth defects. In spite of an effective vaccine, RuV disease remains a serious problem in many developing countries. RuV infection of host cells involves endocytic uptake and low pH-triggered membrane fusion and is unusual in its requirement for calcium binding by the membrane fusion protein. Here we addressed the mechanism of the calcium requirement and the required location of calcium during virus entry. Both calcium and low pH were essential during the virus fusion reaction, which was shown to occur in the early endosome compartment. PMID:27122589

Application of proton boron fusion reaction to radiation therapy: A Monte Carlo simulation study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yoon, Do-Kun; Jung, Joo-Young; Suh, Tae Suk, E-mail: suhsanta@catholic.ac.kr

2014-12-01

Three alpha particles are emitted from the point of reaction between a proton and boron. The alpha particles are effective in inducing the death of a tumor cell. After boron is accumulated in the tumor region, the emitted from outside the body proton can react with the boron in the tumor region. An increase of the proton's maximum dose level is caused by the boron and only the tumor cell is damaged more critically. In addition, a prompt gamma ray is emitted from the proton boron reaction point. Here, we show that the effectiveness of the proton boron fusion therapymore » was verified using Monte Carlo simulations. We found that a dramatic increase by more than half of the proton's maximum dose level was induced by the boron in the tumor region. This increase occurred only when the proton's maximum dose point was located within the boron uptake region. In addition, the 719 keV prompt gamma ray peak produced by the proton boron fusion reaction was positively detected. This therapy method features the advantages such as the application of Bragg-peak to the therapy, the accurate targeting of tumor, improved therapy effects, and the monitoring of the therapy region during treatment.« less

The MIT HEDP Accelerator Facility for education and advanced diagnostics development for OMEGA, Z and the NIF

NASA Astrophysics Data System (ADS)

Petrasso, R.; Gatu Johnson, M.; Armstrong, E.; Han, H. W.; Kabadi, N.; Lahmann, B.; Orozco, D.; Rojas Herrera, J.; Sio, H.; Sutcliffe, G.; Frenje, J.; Li, C. K.; Séguin, F. H.; Leeper, R.; Ruiz, C. L.; Sangster, T. C.

2015-11-01

The MIT HEDP Accelerator Facility utilizes a 135-keV linear electrostatic ion accelerator, a D-T neutron source and two x-ray sources for development and characterization of nuclear diagnostics for OMEGA, Z, and the NIF. The ion accelerator generates D-D and D-3He fusion products through acceleration of D ions onto a 3He-doped Erbium-Deuteride target. Fusion reaction rates around 106 s-1 are routinely achieved, and fluence and energy of the fusion products have been accurately characterized. The D-T neutron source generates up to 6 × 108 neutrons/s. The two x-ray generators produce spectra with peak energies of 35 keV and 225 keV and maximum dose rates of 0.5 Gy/min and 12 Gy/min, respectively. Diagnostics developed and calibrated at this facility include CR-39 based charged-particle spectrometers, neutron detectors, and the particle Time-Of-Flight (pTOF) and Magnetic PTOF CVD-diamond-based bang time detectors. The accelerator is also a vital tool in the education of graduate and undergraduate students at MIT. This work was supported in part by SNL, DOE, LLE and LLNL.

Polymerase chain reaction-based detection of myc transduction in feline leukemia virus-infected cats.

PubMed

Sumi, Ryosuke; Miyake, Ariko; Endo, Taiji; Ohsato, Yoshiharu; Ngo, Minh Ha; Nishigaki, Kazuo

2018-04-01

Feline lymphomas are associated with the transduction and activation of cellular proto-oncogenes, such as c-myc, by feline leukemia virus (FeLV). We describe a polymerase chain reaction assay for detection of myc transduction usable in clinical diagnosis. The assay targets c-myc exons 2 and 3, which together result in a FeLV-specific fusion gene following c-myc transduction. When this assay was conducted on FeLV-infected feline tissues submitted for clinical diagnosis of tumors, myc transduction was detected in 14% of T-cell lymphoma/leukemias. This newly established system could become a useful diagnostic tool in veterinary medicine.

New method of a "point-like" neutron source creation based on sharp focusing of high-current deuteron beam onto deuterium-saturated target for neutron tomography

NASA Astrophysics Data System (ADS)

Golubev, S.; Skalyga, V.; Izotov, I.; Sidorov, A.

2017-02-01

A possibility of a compact powerful point-like neutron source creation is discussed. Neutron yield of the source based on deuterium-deuterium (D-D) reaction is estimated at the level of 1011 s-1 (1013 s-1 for deuterium-tritium reaction). The fusion takes place due to bombardment of deuterium- (or tritium) loaded target by high-current focused deuterium ion beam with energy of 100 keV. The ion beam is formed by means of high-current quasi-gasdynamic ion source of a new generation based on an electron cyclotron resonance (ECR) discharge in an open magnetic trap sustained by powerful microwave radiation. The prospects of proposed generator for neutron tomography are discussed. Suggested method is compared to the point-like neutron sources based on a spark produced by powerful femtosecond laser pulses.

Engineering Styrene Monooxygenase for Biocatalysis: Reductase-Epoxidase Fusion Proteins.

PubMed

Heine, Thomas; Tucker, Kathryn; Okonkwo, Nonye; Assefa, Berhanegebriel; Conrad, Catleen; Scholtissek, Anika; Schlömann, Michael; Gassner, George; Tischler, Dirk

2017-04-01

The enantioselective epoxidation of styrene and related compounds by two-component styrene monooxygenases (SMOs) has targeted these enzymes for development as biocatalysts. In the present work, we prepare genetically engineered fusion proteins that join the C-terminus of the epoxidase (StyA) to the N-terminus of the reductase (StyB) through a linker peptide and demonstrate their utility as biocatalysts in the synthesis of Tyrain purple and other indigoid dyes. A single-vector expression system offers a simplified platform for transformation and expansion of the catalytic function of styrene monooxygenases, and the resulting fusion proteins are self-regulated and couple efficiently NADH oxidation to styrene epoxidation. We find that the reductase domain proceeds through a sequential ternary-complex mechanism at low FAD concentration and a double-displacement mechanism at higher concentrations of FAD. Single-turnover studies indicate an observed rate constant for FAD-to-FAD hydride transfer of ~8 s -1 . This step is rate limiting in the styrene epoxidation reaction and helps to ensure that flavin reduction and styrene epoxidation reactions proceed without wasteful side reactions. Comparison of the reductase activity of the fusion proteins with the naturally occurring reductase, SMOB, and N-terminally histidine-tagged reductase, NSMOB, suggests that the observed changes in catalytic mechanism are due in part to an increase in flavin-binding affinity associated with the N-terminal extension of the reductase.

The conserved glycine residues in the transmembrane domain of the Semliki Forest virus fusion protein are not required for assembly and fusion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liao Maofu; Kielian, Margaret

2005-02-05

The alphavirus Semliki Forest virus (SFV) infects cells via a low pH-triggered fusion reaction mediated by the viral E1 protein. Both the E1 fusion peptide and transmembrane (TM) domain are essential for membrane fusion, but the functional requirements for the TM domain are poorly understood. Here we explored the role of the five TM domain glycine residues, including the highly conserved glycine pair at E1 residues 415/416. SFV mutants with alanine substitutions for individual or all five glycine residues (5G/A) showed growth kinetics and fusion pH dependence similar to those of wild-type SFV. Mutants with increasing substitution of glycine residuesmore » showed an increasingly more stringent requirement for cholesterol during fusion. The 5G/A mutant showed decreased fusion kinetics and extent in fluorescent lipid mixing assays. TM domain glycine residues thus are not required for efficient SFV fusion or assembly but can cause subtle effects on the properties of membrane fusion.« less

Multifunctional cellulase catalysis targeted by fusion to different carbohydrate-binding modules

DOE PAGES

Walker, Johnnie A.; Takasuka, Taichi E.; Deng, Kai; ...

2015-12-21

Carbohydrate binding modules (CBMs) bind polysaccharides and help target glycoside hydrolases catalytic domains to their appropriate carbohydrate substrates. To better understand how CBMs can improve cellulolytic enzyme reactivity, representatives from each of the 18 families of CBM found in Ruminoclostridium thermocellum were fused to the multifunctional GH5 catalytic domain of CelE (Cthe_0797, CelEcc), which can hydrolyze numerous types of polysaccharides including cellulose, mannan, and xylan. Since CelE is a cellulosomal enzyme, none of these fusions to a CBM previously existed. CelEcc_CBM fusions were assayed for their ability to hydrolyze cellulose, lichenan, xylan, and mannan. Several CelEcc_CBM fusions showed enhanced hydrolyticmore » activity with different substrates relative to the fusion to CBM3a from the cellulosome scaffoldin, which has high affinity for binding to crystalline cellulose. Additional binding studies and quantitative catalysis studies using nanostructure-initiator mass spectrometry (NIMS) were carried out with the CBM3a, CBM6, CBM30, and CBM44 fusion enzymes. In general, and consistent with observations of others, enhanced enzyme reactivity was correlated with moderate binding affinity of the CBM. Numerical analysis of reaction time courses showed that CelEcc_CBM44, a combination of a multifunctional enzyme domain with a CBM having broad binding specificity, gave the fastest rates for hydrolysis of both the hexose and pentose fractions of ionic-liquid pretreated switchgrass. In conclusion, we have shown that fusions of different CBMs to a single multifunctional GH5 catalytic domain can increase its rate of reaction with different pure polysaccharides and with pretreated biomass. This fusion approach, incorporating domains with broad specificity for binding and catalysis, provides a new avenue to improve reactivity of simple combinations of enzymes within the complexity of plant biomass.« less

Results of an attempt to measure increased rates of the reaction D-2 + D-2 yields He-3 + n in a nonelectrochemical cold fusion experiment

NASA Technical Reports Server (NTRS)

Fralick, Gustave C.; Decker, Arthur J.; Blue, James W.

1989-01-01

An experiment was performed to look for evidence of deuterium fusion in palladium. The experiment, which involved introducing deuterium into the palladium filter of a hydrogen purifier, was designed to detect neutrons produced in the reaction D-2 + D-2 yields He-3 + n as well as heat production. The neutron counts for deuterium did not differ significantly from background or from the counts for a hydrogen control. Heat production was detected when deuterium, but not hydrogen, was pumped from the purifier.

Nuclear Reactions: Studying Peaceful Applications in the Middle and Secondary School.

ERIC Educational Resources Information Center

Szymanski Sunal, Cynthia; Sunal, Dennis W.

1999-01-01

Asserts that students must learn about nuclear fission and fusion in the social studies curriculum to help them develop a foundation for considering the social issues associated with the everyday use of nuclear reactions. Gives background on the two types of reactions and provides three lessons for middle and secondary classrooms. (CMK)

Role of the supersymmetric semiclassical approach in barrier penetration and heavy-ion fusion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sil, T.; Dutt, R.; Varshni, Y.P.

1994-11-01

The problem of heavy-ion fusion reactions in the one-dimensional barrier penetration model (BPM) has been reexamined in light of supersymmetry-inspired WKB (SWKB) method. Motivated by our recent work [Phys. Lett. A 184, 209 (1994)] describing the SWKB method for the computation of the transmission coefficient [ital T]([ital E]), we have performed similar calculations for a potential barrier that mimics the proximity potential obtained by fitting experimentally measured fusion cross section [sigma][sub [ital F

The kinetic stabilizer: a route to simpler tandem mirror systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Post, R F

2001-02-02

As we enter the new millennium there is a growing urgency to address the issue of finding long-range solutions to the world's energy needs. Fusion offers such a solution, provided economically viable means can be found to extract useful energy from fusion reactions. While the magnetic confinement approach to fusion has a long and productive history, to date the mainline approaches to magnetic confinement, namely closed systems such as the tokamak, appear to many as being too large and complex to be acceptable economically, despite the impressive progress that has made toward the achievement of fusion-relevant confinement parameters. Thus theremore » is a growing feeling that it is imperative to search for new and simpler approaches to magnetic fusion, ones that might lead to smaller and more economically attractive fusion power plants.« less

Distortion of bulk-ion distribution function due to nuclear elastic scattering and its effect on T(d,n)4He reaction rate coefficient in neutral-beam-injected deuterium-tritium plasmas

NASA Astrophysics Data System (ADS)

Matsuura, H.; Nakao, Y.

2007-05-01

An effect of nuclear elastic scattering on the rate coefficient of fusion reaction between field deuteron and triton in the presence of neutral beam injection heating is studied. Without assuming a Maxwellian for bulk-ion distribution function, the Boltzmann-Fokker-Planck (BFP) equations for field (bulk) deuteron, field (bulk) triton, α-particle, and beam deuteron are simultaneously solved in an ITER-like deuterium-tritium thermonuclear plasma [R. Aymar, Fusion Eng. Des. 55, 107 (2001)]. The BFP calculation shows that enhancement of the reaction rate coefficient due to knock-on tail formation in fuel-ion distribution functions becomes appreciable, especially in the case of low-density operations.

Probing the fusion of neutron-rich nuclei with re-accelerated radioactive beams

DOE PAGES

Vadas, J.; Singh, Varinderjit; Wiggins, B. B.; ...

2018-03-27

Here, we report the first measurement of the fusion excitation functions for 39,47K + 28Si at near-barrier energies. Evaporation residues resulting from the fusion process were identified by direct measurement of their energy and time-of-flight with high geometric efficiency. At the lowest incident energy, the cross section measured for the neutron-rich 47K-induced reaction is ≈6 times larger than that of the β-stable system. This experimental approach, both in measurement and in analysis, demonstrates how to efficiently measure fusion with low-intensity re-accelerated radioactive beams, establishing the framework for future studies.

Probing the fusion of neutron-rich nuclei with re-accelerated radioactive beams

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vadas, J.; Singh, Varinderjit; Wiggins, B. B.

Here, we report the first measurement of the fusion excitation functions for 39,47K + 28Si at near-barrier energies. Evaporation residues resulting from the fusion process were identified by direct measurement of their energy and time-of-flight with high geometric efficiency. At the lowest incident energy, the cross section measured for the neutron-rich 47K-induced reaction is ≈6 times larger than that of the β-stable system. This experimental approach, both in measurement and in analysis, demonstrates how to efficiently measure fusion with low-intensity re-accelerated radioactive beams, establishing the framework for future studies.

Probing spherical tokamak plasmas using charged fusion products

NASA Astrophysics Data System (ADS)

Boeglin, Werner U.; Perez, Ramona V.; Darrow, Douglass S.; Cecconello, Marco; Klimek, Iwona; Allan, Scott Y.; Akers, Rob J.; Jones, Owen M.; Keeling, David L.; McClements, Ken G.; Scannell, Rory

2015-11-01

The detection of charged fusion products, such as protons and tritons resulting from D(d,p)t reactions, can be used to determine the fusion reaction rate profile in large spherical tokamak plasmas with neutral beam heating. The time resolution of a diagnostic of this type makes it possible to study the slowly-varying beam density profile, as well as rapid changes resulting from MHD instabilities. A 4-channel prototype proton detector (PD) was installed and operated on the MAST spherical tokamak in August/September 2013, and a new 6-channel system for the NSTX-U spherical tokamak is under construction. PD and neutron camera measurements obtained on MAST will be compared with TRANSP calculations, and the design of the new NSTX-U system will be presented, together with the first results from this diagnostic, if available. Supported in part by DOE DE-SC0001157.

Dynamical approach to fusion-fission process in superheavy mass region

NASA Astrophysics Data System (ADS)

Aritomo, Y.; Hinde, D. J.; Wakhle, A.; du Rietz, R.; Dasgupta, M.; Hagino, K.; Chiba, S.; Nishio, K.

2012-10-01

In order to describe heavy-ion fusion reactions around the Coulomb barrier with an actinide target nucleus, we propose a model which combines the coupled-channels approach and a fluctuation-dissipation model for dynamical calculations. This model takes into account couplings to the collective states of the interacting nuclei in the penetration of the Coulomb barrier and the subsequent dynamical evolution of a nuclear shape from the contact configuration. In the fluctuation-dissipation model with a Langevin equation, the effect of nuclear orientation at the initial impact on the prolately deformed target nucleus is considered. Fusion-fission, quasifission and deep quasifission are separated as different Langevin trajectories on the potential energy surface. Using this model, we analyze the experimental data for the mass distribution of fission fragments (MDFF) in the reaction of 36S+238U at several incident energies around the Coulomb barrier.

Incomplete mass transfer processes in 28Si +93Nb reaction

NASA Astrophysics Data System (ADS)

Tripathi, R.; Sodaye, S.; Ramachandran, K.; Sharma, S. K.; Pujari, P. K.

Cross sections of reaction products were measured in 28Si +93Nb reaction using recoil catcher technique involving by off-line gamma-ray spectrometry at beam energies of 105 and 155MeV. At Elab = 155MeV, the contribution from different incomplete mass transfer processes is investigated. Results of the present studies show the contribution from deep inelastic collision (DIC), massive transfer or incomplete fusion (ICF) and quasi-elastic transfer (QET). The contribution from massive transfer reactions was confirmed from the fractional yield of the reaction products in the forward catcher foil. The present results are different from those from the reactions with comparatively higher entrance channel mass asymmetry with lighter projectiles, for which dominant transfer processes are ICF and QET which involve mass transfer predominantly from projectile to target. The N/Z values of the products close to the target mass were observed to be in a wide range, starting from N/Z of the target (93Nb) and extending slightly below the N/Z of the composite system, consistent with the contribution from DIC and QET reactions. At Elab = 105MeV, a small contribution from QET was observed in addition to complete fusion.

Incomplete fusion analysis of the 7Li-induced reaction on 93Nb within 3-6.5 MeV/nucleon

NASA Astrophysics Data System (ADS)

Kumar, Deepak; Maiti, Moumita

2017-10-01

Background: It is understood from the recent experimental studies that prompt/resonant breakup, and transfer followed by breakup in the weakly bound Li,76-induced reactions play a significant role in the complete-incomplete fusion (CF-ICF), suppression/enhancement in the fusion cross section around the Coulomb barrier. Purpose: Investigation of ICF over CF by measuring cross sections of the populated residues, produced via different channels in the 7Li-induced reaction on a natNb target within the 3-6.5 MeV/nucleon energy region. Method: The 7Li beam was allowed to hit the self-supporting 93Nb targets, backed by the aluminium (Al) foil alternately, within 3-6.5 MeV/nucleon energy. Populated residues were identified by offline γ -ray spectrometry. Measured excitation functions of different channels were compared with different equilibrium and pre-equilibrium models. Result: The enhancement in cross sections in the proton (˜20 -30 MeV) and α -emitting channels, which may be ascribed to ICF, was observed in the measured energy range when compared to the Hauser-Feshbach and exciton model calculations using empire, which satisfactorily reproduces the neutron channels, compared to the Weisskopf-Ewing model and hybrid Monte Carlo calculations. The increment of the incomplete fusion fraction was observed with rising projectile energy. Conclusion: Contrary to the alice14, experimental results are well reproduced by the empire throughout the measured energy range. The signature of ICF over CF indicates that the breakup/transfer processes are involved in the weakly bound 7Li-induced reaction on 93Nb slightly above the Coulomb barrier.

Multinucleon transfer in O,1816,19F+208Pb reactions at energies near the fusion barrier

NASA Astrophysics Data System (ADS)

Rafferty, D. C.; Dasgupta, M.; Hinde, D. J.; Simenel, C.; Simpson, E. C.; Williams, E.; Carter, I. P.; Cook, K. J.; Luong, D. H.; McNeil, S. D.; Ramachandran, K.; Vo-Phuoc, K.; Wakhle, A.

2016-08-01

Background: Nuclear reactions are complex, involving collisions between composite systems where many-body dynamics determines outcomes. Successful models have been developed to explain particular reaction outcomes in distinct energy and mass regimes, but a unifying picture remains elusive. The irreversible transfer of kinetic energy from the relative motion of the collision partners to their internal states, as is known to occur in deep inelastic collisions, has yet to be successfully incorporated explicitly into fully quantal reaction models. The influence of these processes on fusion is not yet quantitatively understood. Purpose: To investigate the population of high excitation energies in transfer reactions at sub-barrier energies, which are precursors to deep inelastic processes, and their dependence on the internuclear separation. Methods: Transfer probabilities and excitation energy spectra have been measured in collisions of O,1816,19F+208Pb , at various energies below and around the fusion barrier, by detecting the backscattered projectile-like fragments in a Δ E -E telescope. Results: The relative yields of different transfer outcomes are strongly driven by Q values, but change with the internuclear separation. In 16O+208Pb , single nucleon transfer dominates, with a strong contribution from -2 p transfer close to the Coulomb barrier, though this channel becomes less significant in relation to the -2 p 2 n transfer channel at larger separations. For 18O+208Pb , the -2 p 2 n channel is the dominant charge transfer mode at all separations. In the reactions with 19F,-3 p 2 n transfer is significant close to the barrier, but falls off rapidly with energy. Multinucleon transfer processes are shown to lead to high excitation energies (up to ˜15 MeV), which is distinct from single nucleon transfer modes which predominantly populate states at low excitation energy. Conclusions: Kinetic energy is transferred into internal excitations following transfer, with this energy being distributed over a larger number of states and to higher excitations with increasing numbers of transferred nucleons. Multinucleon transfer is thus a mechanism by which energy can be dissipated from the relative motion before reaching the fusion barrier radius.

Nuclear fusion at heavy water clusters collision with deuterized targets

NASA Astrophysics Data System (ADS)

Bolotin, Yu. L.; Inopin, E. V.; Lyashko, Yu. V.; Slabospitskij, R. P.

A review of research developed in different laboratories on animal heavy particle yield in D-D fusion reactions induced by heavy water cluster collisions with deuterized targets is presented. Analysis of data shows, on one hand, nontriviality of experimental results and inadequacy of their interpretation and, on the other hand, the multipromising prospects of such a research.

Catalysis of Nuclear Reactions by Electrons

NASA Astrophysics Data System (ADS)

Lipoglavšek, Matej

2018-01-01

Electron screening enhances nuclear reaction cross sections at low energies. We studied the nuclear reaction 1H(19F,αγ)16O in inverse kinematics in different solid hydrogen targets. Measured resonance strengths differed by up to a factor of 10 in different targets. We also studied the 2H(p,γ)3He fusion reaction and observed electrons emitted as reaction products instead of γ rays. In this case electron screening greatly enhances internal conversion probability.

Condensed Matter Nuclear Science

NASA Astrophysics Data System (ADS)

Biberian, Jean-Paul

2006-02-01

1. General. A tribute to gene Mallove - the "Genie" reactor / K. Wallace and R. Stringham. An update of LENR for ICCF-11 (short course, 10/31/04) / E. Storms. New physical effects in metal deuterides / P. L. Hagelstein ... [et al.]. Reproducibility, controllability, and optimization of LENR experiments / D. J. Nagel -- 2. Experiments. Electrochemistry. Evidence of electromagnetic radiation from Ni-H systems / S. Focardi ... [et al.]. Superwave reality / I. Dardik. Excess heat in electrolysis experiments at energetics technologies / I. Dardik ... [et al.]. "Excess heat" during electrolysis in platinum/K[symbol]CO[symbol]/nickel light water system / J. Tian ... [et al.]. Innovative procedure for the, in situ, measurement of the resistive thermal coefficient of H(D)/Pd during electrolysis; cross-comparison of new elements detected in the Th-Hg-Pd-D(H) electrolytic cells / F. Celani ... [et al.]. Emergence of a high-temperature superconductivity in hydrogen cycled Pd compounds as an evidence for superstoihiometric H/D sites / A. Lipson ... [et al.]. Plasma electrolysis. Calorimetry of energy-efficient glow discharge - apparatus design and calibration / T. B. Benson and T. O. Passell. Generation of heat and products during plasma electrolysis / T. Mizuno ... [et al.]. Glow discharge. Excess heat production in Pd/D during periodic pulse discharge current in various conditions / A. B. Karabut. Beam experiments. Accelerator experiments and theoretical models for the electron screening effect in metallic environments / A. Huke, K. Czerski, and P. Heide. Evidence for a target-material dependence of the neutron-proton branching ratio in d+d reactions for deuteron energies below 20keV / A. Huke ... [et al.]. Experiments on condensed matter nuclear events in Kobe University / T. Minari ... [et al.]. Electron screening constraints for the cold fusion / K. Czerski, P. Heide, and A. Huke. Cavitation. Low mass 1.6 MHz sonofusion reactor / R. Stringham. Particle detection. Research into characteristics of X-ray emission laser beams from solidstate cathode medium of high-current glow discharge / A. B. Karabut. Charged particles from Ti and Pd foils / L. Kowalski ... [et al.]. Cr-39 track detectors in cold fusion experiments: review and perspectives / A. S. Roussetski. Energetic particle shower in the vapor from electrolysis / R. A. Oriani and J. C. Fisher. Nuclear reactions produced in an operating electrolysis cell / R. A. Oriani and J. C. Fisher. Evidence of microscopic ball lightning in cold fusion experiments / E. H. Lewis. Neutron emission from D[symbol] gas in magnetic fields under low temperature / T. Mizuno ... [et al.]. Energetic charged particle emission from hydrogen-loaded Pd and Ti cathodes and its enhancement by He-4 implantation / A. G. Lipson ... [et al.]. H-D permeation. Observation of nuclear transmutation reactions induced by D[symbol] gas permeation through Pd complexes / Y. Iwamura ... [et al.]. Deuterium (hydrogen) flux permeating through palladium and condensed matter nuclear science / Q. M. Wei ... [et al.]. Triggering. Precursors and the fusion reactions in polarized Pd/D-D[symbol]O system: effect of an external electric field / S. Szpak, P. A. Mosier-Boss, and F. E. Gordon. Calorimetric and neutron diagnostics of liquids during laser irradiation / Yu. N. Bazhutov ... [et al.]. Anomalous neutron capture and plastic deformation of Cu and Pd cathodes during electrolysis in a weak thermalized neutron field: evidence of nuclei-lattice exchange / A. G. Lipson and G. H. Miley. H-D loading. An overview of experimental studies on H/Pd over-loading with thin Pd wires and different electrolytic solutions / A. Spallone ... [et al.] -- 3. Transmutations. Photon and particle emission, heat production, and surface transformation in Ni-H system / E. Campari ... [et al.]. Surface analysis of hydrogen-loaded nickel alloys / E. Campari ... [et al.]. Low-energy nuclear reactions and the leptonic monopole / G. Lochak and L. Urutskoev. Results of analysis of Ti foil after glow discharge with deuterium / I. B. Savvatimova and D. V. Gavritenkov. Enhancement mechanisms of low-energy nuclear reactions / F. A. Gareev, I. E. Zhidkova, and Y. L. Ratis. Co-deposition of palladium with hydrogen isotopes / J. Dash and A. Ambadkar. Variation of the concentration of isotopes copper and zinc in human plasmas of patients affected by cancer / A. Triassi. Transmutation of metal at low energy in a confined plasma in water / D. Cirillo and V. Iorio. The conditions and realization of self-similar Coulomb collapse of condensed target and low-energy laboratory nucleosynthesis / S. V. Adamenko and V. I. Vysotskii. The spatial structure of water and the problem of controlled low-energy nuclear reactions in water matrix / V. I. Vysotskii and A. A. Kornilova. Experiments on controlled decontamination of water mixture of longlived active isotopes in biological cells / V. I. Vysotskii. Assessment of the biological effects of "strange" radiation / E. A. Pryakhin ... [et al.]. Possible nuclear transmutation of nitrogen in the earth's atmosphere / M. Fukuhara. Evidences on the occurrence of LENR-type processes in alchemical transmutations / J. Pérez-Pariente. History of the discovery of transmutation at Texas A&M University / J. O.-M. Bockris -- 4. Theory. Quantum electrodynamics. Concerning the modeling of systems in terms of quantum electro dynamics: the special case of "cold fusion" / M. Abyaneh ... [et al.]. Screening. Theoretical model of the probability of fusion between deuterons within deformed lattices with microcracks at room temperature / F. Fulvio. Resonant tunnelling. Effective interaction potential in the deuterium plasma and multiple resonance scattering / T. Toimela. Multiple scattering theory and condensed matter nuclear science - "super-absorption" in a crystal latice / X. Z. Li ... [et al.]. Ion band states. Framework for understanding LENR processes, using conventional condensed matter physics / S. R. Chubb. I. Bloch ions / T. A. Chubb. II. Inhibited diffusion driven surface transmutations / T. A. Chubb. III. Bloch nuclides, Iwamura transmutations, and Oriani showers / T. A. Chubb. Bose-Einstein condensate. Theoretical study of nuclear reactions induced by Bose-Einstein condensation in Pd / K.-I. Tsuchiya and H. Okumura. Proposal for new experimental tests of the Bose-Einstein condensation mechanism for low-energy nuclear reaction and transmutation processes in deuterium loaded micro- and nano-scale cavities / Y. E. Kim ... [et al.]. Mixtures of charged bosons confined in harmonic traps and Bose-Einstein condensation mechanism for low-energy nuclear reactions and transmutation processes in condensed matters / Y. E. Kim and A. L. Zubarev. Alternative interpretation of low-energy nuclear reaction processes with deuterated metals based on the Bose-Einstein condensation mechanism / Y. E. Kim and T. O. Passell. Multi-body fusion. [symbol]He/[symbol]He production ratios by tetrahedral symmetric condensation / A. Takahashi. Phonon coupling. Phonon-exchange models: some new results / P. L. Hagelstein. Neutron clusters. Cold fusion phenomenon and solid state nuclear physics / H. Kozima. Neutrinos, magnetic monopoles. Neutrino-driven nuclear reactions of cold fusion and transmutation / V. Filimonov. Light monopoles theory: an overview of their effects in physics, chemistry, biology, and nuclear science (weak interactions) / G. Lochak. Electrons clusters and magnetic monopoles / M. Rambaut. Others. Effects of atomic electrons on nuclear stability and radioactive decay / D. V. Filippov, L. I. Urutskoev, and A. A. Rukhadze. Search for erzion nuclear catalysis chains from cosmic ray erzions stopping in organic scintillator / Yu. N. Bazhutov and E. V. Pletnikov. Low-energy nuclear reactions resulting as picometer interactions with similarity to K-shell electron capture / H. Hora ... [et al.] -- 5. Other topics. On the possible magnetic mechanism of shortening the runaway of RBMK-1000 reactor at Chernobyl Nuclear Power Plant / D. V. Filippov ... [et al.]. Cold fusion in the context of a scientific revolution in physics: history and economic ramifications / E. Lewis. The nucleovoltaic cell / D. D. Moon. Introducing the book "Cold Fusion and the Future" / J. Rothwell. Recent cold fusion claims: are they valid? / L. Kowalski. History of attempts to publish a paper / L. Kowalski.

Laser or charged-particle-beam fusion reactor with direct electric generation by magnetic flux compression

DOEpatents

Lasche, George P.

1988-01-01

A high-power-density laser or charged-particle-beam fusion reactor system maximizes the directed kinetic energy imparted to a large mass of liquid lithium by a centrally located fusion target. A fusion target is embedded in a large mass of lithium, of sufficient radius to act as a tritium breeding blanket, and provided with ports for the access of beam energy to implode the target. The directed kinetic energy is converted directly to electricity with high efficiency by work done against a pulsed magnetic field applied exterior to the lithium. Because the system maximizes the blanket thickness per unit volume of lithium, neutron-induced radioactivities in the reaction chamber wall are several orders of magnitude less than is typical of other fusion reactor systems.

Quantifying Fusion Born Ion Populations in Magnetically Confined Plasmas using Ion Cyclotron Emission

DOE PAGES

Carbajal, L.; Warwick Univ., Coventry; Dendy, R. O.; ...

2017-03-07

Ion cyclotron emission (ICE) offers unique promise as a diagnostic of the fusion born alpha-particle population in magnetically confined plasmas. Pioneering observations from JET and TFTR found that ICE intensity P ICE scales approximately linearly with the measured neutron flux from fusion reactions, and with the inferred concentration, n /n i , of fusion-born alpha-particles confined within the plasma. We present fully nonlinear self-consistent kinetic simulations that reproduce this scaling for the first time. This resolves a longstanding question in the physics of fusion alpha particle confinement and stability in MCF plasmas. It confirms the MCI as the likely emissionmore » mechanism and greatly strengthens the basis for diagnostic exploitation of ICE in future burning plasmas.« less

Systematic study of 16O-induced fusion with the improved quantum molecular dynamics model

NASA Astrophysics Data System (ADS)

Wang, Ning; Zhao, Kai; Li, Zhuxia

2014-11-01

The heavy-ion fusion reactions with 16O bombarding on 62Ni,65Cu,74Ge,148Nd,180Hf,186W,208Pb,238U are systematically investigated with the improved quantum molecular dynamics model. The fusion cross sections at energies near and above the Coulomb barriers can be reasonably well reproduced by using this semiclassical microscopic transport model with the parameter sets SkP* and IQ3a. The dynamical nucleus-nucleus potentials and the influence of Fermi constraint on the fusion process are also studied simultaneously. In addition to the mean field, the Fermi constraint also plays a key role for the reliable description of the fusion process and for improving the stability of fragments in heavy-ion collisions.

Laser or charged-particle-beam fusion reactor with direct electric generation by magnetic flux compression

DOEpatents

Lasche, G.P.

1987-02-20

A high-power-density-laser or charged-particle-beam fusion reactor system maximizes the directed kinetic energy imparted to a large mass of liquid lithium by a centrally located fusion target. A fusion target is embedded in a large mass of lithium, of sufficient radius to act as a tritium breeding blanket, and provided with ports for the access of beam energy to implode the target. The directed kinetic energy is converted directly to electricity with high efficiency by work done against a pulsed magnetic field applied exterior to the lithium. Because the system maximizes the blanket thickness per unit volume of lithium, neutron-induced radioactivities in the reaction chamber wall are several orders of magnitude less than is typical of other fusion reactor systems. 25 figs.

Conceptual design of the early implementation of the NEutron Detector Array (NEDA) with AGATA

NASA Astrophysics Data System (ADS)

Hüyük, Tayfun; Di Nitto, Antonio; Jaworski, Grzegorz; Gadea, Andrés; Javier Valiente-Dobón, José; Nyberg, Johan; Palacz, Marcin; Söderström, Pär-Anders; Jose Aliaga-Varea, Ramon; de Angelis, Giacomo; Ataç, Ayşe; Collado, Javier; Domingo-Pardo, Cesar; Egea, Francisco Javier; Erduran, Nizamettin; Ertürk, Sefa; de France, Gilles; Gadea, Rafael; González, Vicente; Herrero-Bosch, Vicente; Kaşkaş, Ayşe; Modamio, Victor; Moszynski, Marek; Sanchis, Enrique; Triossi, Andrea; Wadsworth, Robert

2016-03-01

The NEutron Detector Array (NEDA) project aims at the construction of a new high-efficiency compact neutron detector array to be coupled with large γ-ray arrays such as AGATA. The application of NEDA ranges from its use as selective neutron multiplicity filter for fusion-evaporation reaction to a large solid angle neutron tagging device. In the present work, possible configurations for the NEDA coupled with the Neutron Wall for the early implementation with AGATA has been simulated, using Monte Carlo techniques, in order to evaluate their performance figures. The goal of this early NEDA implementation is to improve, with respect to previous instruments, efficiency and capability to select multiplicity for fusion-evaporation reaction channels in which 1, 2 or 3 neutrons are emitted. Each NEDA detector unit has the shape of a regular hexagonal prism with a volume of about 3.23l and it is filled with the EJ301 liquid scintillator, that presents good neutron- γ discrimination properties. The simulations have been performed using a fusion-evaporation event generator that has been validated with a set of experimental data obtained in the 58Ni + 56Fe reaction measured with the Neutron Wall detector array.

Effect of a single dose of dextromethorphan on psychomotor performance and working memory capacity.

PubMed

Al-Kuraishy, Hayder M; Al-Gareeb, Ali I; Ashor, Ammar Waham

2012-04-01

Previous studies show that the prolonged use of dextromethorphan produces cognitive deterioration in humans. The aim of this study was to investigate the effect of a single dose of dextroemthrophan on psychomotor performance and working memory capacity. This is a randomized, double-blind, controlled, and prospective study. Thirty-six (17 women, 19 men) medical students enrolled in the study; half of them (7 women, 11 men) were given placebo, while the other half (10 women, 8 men) received dextromethorphan. The choice reaction time, critical flicker fusion threshold, and N-back working memory task were measured before and after 2 h of taking the drugs. Dextromethorphan showed a significant deterioration in the 3-back working memory task (P<0.05). No significant changes were seen as regards the choice reaction time components (total, recognition, motor) and critical flicker fusion threshold (P>0.05). On the other hand, placebo showed no significant changes as regards the choice reaction time, critical flicker fusion threshold, and N-back working memory task (P>0.05). A single dose of dextromethorphan has no effect on attention and arousal but may significantly impair the working memory capacity.

Directional Track Selection Technique in CR39 SSNTD for lowyield reaction experiments

NASA Astrophysics Data System (ADS)

Ingenito, Francesco; Andreoli, Pierluigi; Batani, Dimitri; Bonasera, Aldo; Boutoux, Guillaume; Burgy, Frederic; Cipriani, Mattia; Consoli, Fabrizio; Cristofari, Giuseppe; De Angelis, Riccardo; Di Giorgio, Giorgio; Ducret, Jean Eric; Giulietti, Danilo; Jakubowska, Katarzyna

2018-01-01

There is a great interest in the study of p-11B aneutronic nuclear fusion reactions, both for energy production and for determination of fusion cross-sections at low energies. In this context we performed experiments at CELIA in which energetic protons, accelerated by the laser ECLIPSE, were directed toward a solid Boron target. Because of the small cross-sections at these energies the number of expected reactions is low. CR39 Solid-State Nuclear Track Detectors (SSNTD) were used to detect the alpha particles produced. Because of the low expected yield, it is difficult to discriminate the tracks due to true fusion products from those due to natural background in the CR39. To this purpose we developed a methodology of particle recognition according to their direction with respect to the detector normal, able to determine the position of their source. We applied this to the specific experiment geometry, so to select from all the tracks those due to particles coming from the region of interaction between accelerated protons and solid boron target. This technique can be of great help on the analysis of SSNTD in experiments with low yield reactions, but can be also generally applied to any experiment where particles reach the track detector with known directions, and for example to improve the detection limit of particle spectrometers using CR39.

Cross sections of projectile-like fragments in the reaction {sup 19}F+{sup 66}Zn in the beam energy range of 3-6 MeV/nucleon

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tripathi, R.; Sudarshan, K.; Sodaye, S.

2009-06-15

Angular distributions of projectile-like fragments (PLFs) have been measured in the reaction {sup 19}F+{sup 66}Zn at E{sub lab}=61,82,92, and 109 MeV to understand their formation in the low energy domain (< or approx. 7 MeV nucleon). In this energy range, maximum angular momentum 'l{sub max}' in the reaction is lower than or close to the critical or limiting angular momentum for complete fusion 'l{sub lim}(CF).' The sum-rule model was modified to explain the cross sections of PLFs in the present study. For the first time, the modified sum-rule model, with a competition of incomplete fusion (ICF) reaction with complete fusionmore » below l{sub lim}(CF) reasonably reproduced the cross sections of PLFs in the beam energy range of the present study. It was observed that the cross sections of lighter PLFs fall more rapidly with decreasing beam energy compared to those of heavier PLFs, suggesting a change in the reaction mechanism from heavier to lighter PLFs. Transfer probabilities for peripheral collisions were calculated within the framework of a semiclassical formalism. The parameters of the nuclear potential required for the calculation of transfer probability were obtained by fitting the elastic scattering data measured in the present work. Calculated transfer probabilities were significantly lower compared to the corresponding experimental values, suggesting a significant overlap of the projectile and the target nuclei in incomplete fusion reactions. The present analysis showed that the overlap of the projectile and the target nuclei increases with increasing mass transfer at a given beam energy and for a given PLF, overlap increases with increasing beam energy.« less

Advanced Fusion Reactors for Space Propulsion and Power Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chapman, John J.

In recent years the methodology proposed for conversion of light elements into energy via fusion has made steady progress. Scientific studies and engineering efforts in advanced fusion systems designs have introduced some new concepts with unique aspects including consideration of Aneutronic fuels. The plant parameters for harnessing aneutronic fusion appear more exigent than those required for the conventional fusion fuel cycle. However aneutronic fusion propulsion plants for Space deployment will ultimately offer the possibility of enhanced performance from nuclear gain as compared to existing ionic engines as well as providing a clean solution to Planetary Protection considerations and requirements. Protonmore » triggered 11Boron fuel (p- 11B) will produce abundant ion kinetic energy for In-Space vectored thrust. Thus energetic alpha particles' exhaust momentum can be used directly to produce high Isp thrust and also offer possibility of power conversion into electricity. p-11B is an advanced fusion plant fuel with well understood reaction kinematics but will require some new conceptual thinking as to the most effective implementation.« less

Advanced Fusion Reactors for Space Propulsion and Power Systems

NASA Technical Reports Server (NTRS)

Chapman, John J.

2011-01-01

In recent years the methodology proposed for conversion of light elements into energy via fusion has made steady progress. Scientific studies and engineering efforts in advanced fusion systems designs have introduced some new concepts with unique aspects including consideration of Aneutronic fuels. The plant parameters for harnessing aneutronic fusion appear more exigent than those required for the conventional fusion fuel cycle. However aneutronic fusion propulsion plants for Space deployment will ultimately offer the possibility of enhanced performance from nuclear gain as compared to existing ionic engines as well as providing a clean solution to Planetary Protection considerations and requirements. Proton triggered 11Boron fuel (p- 11B) will produce abundant ion kinetic energy for In-Space vectored thrust. Thus energetic alpha particles "exhaust" momentum can be used directly to produce high ISP thrust and also offer possibility of power conversion into electricity. p- 11B is an advanced fusion plant fuel with well understood reaction kinematics but will require some new conceptual thinking as to the most effective implementation.

Additive effects on the energy barrier for synaptic vesicle fusion cause supralinear effects on the vesicle fusion rate.

PubMed

Schotten, Sebastiaan; Meijer, Marieke; Walter, Alexander Matthias; Huson, Vincent; Mamer, Lauren; Kalogreades, Lawrence; ter Veer, Mirelle; Ruiter, Marvin; Brose, Nils; Rosenmund, Christian; Sørensen, Jakob Balslev; Verhage, Matthijs; Cornelisse, Lennart Niels

2015-04-14

The energy required to fuse synaptic vesicles with the plasma membrane ('activation energy') is considered a major determinant in synaptic efficacy. From reaction rate theory, we predict that a class of modulations exists, which utilize linear modulation of the energy barrier for fusion to achieve supralinear effects on the fusion rate. To test this prediction experimentally, we developed a method to assess the number of releasable vesicles, rate constants for vesicle priming, unpriming, and fusion, and the activation energy for fusion by fitting a vesicle state model to synaptic responses induced by hypertonic solutions. We show that complexinI/II deficiency or phorbol ester stimulation indeed affects responses to hypertonic solution in a supralinear manner. An additive vs multiplicative relationship between activation energy and fusion rate provides a novel explanation for previously observed non-linear effects of genetic/pharmacological perturbations on synaptic transmission and a novel interpretation of the cooperative nature of Ca(2+)-dependent release.

Fuel gain exceeding unity in an inertially confined fusion implosion.

PubMed

Hurricane, O A; Callahan, D A; Casey, D T; Celliers, P M; Cerjan, C; Dewald, E L; Dittrich, T R; Döppner, T; Hinkel, D E; Berzak Hopkins, L F; Kline, J L; Le Pape, S; Ma, T; MacPhee, A G; Milovich, J L; Pak, A; Park, H-S; Patel, P K; Remington, B A; Salmonson, J D; Springer, P T; Tommasini, R

2014-02-20

Ignition is needed to make fusion energy a viable alternative energy source, but has yet to be achieved. A key step on the way to ignition is to have the energy generated through fusion reactions in an inertially confined fusion plasma exceed the amount of energy deposited into the deuterium-tritium fusion fuel and hotspot during the implosion process, resulting in a fuel gain greater than unity. Here we report the achievement of fusion fuel gains exceeding unity on the US National Ignition Facility using a 'high-foot' implosion method, which is a manipulation of the laser pulse shape in a way that reduces instability in the implosion. These experiments show an order-of-magnitude improvement in yield performance over past deuterium-tritium implosion experiments. We also see a significant contribution to the yield from α-particle self-heating and evidence for the 'bootstrapping' required to accelerate the deuterium-tritium fusion burn to eventually 'run away' and ignite.

The NASA-Lewis program on fusion energy for space power and propulsion, 1958-1978

NASA Technical Reports Server (NTRS)

Schulze, Norman R.; Roth, J. Reece

1990-01-01

An historical synopsis is provided of the NASA-Lewis research program on fusion energy for space power and propulsion systems. It was initiated to explore the potential applications of fusion energy to space power and propulsion systems. Some fusion related accomplishments and program areas covered include: basic research on the Electric Field Bumpy Torus (EFBT) magnetoelectric fusion containment concept, including identification of its radial transport mechanism and confinement time scaling; operation of the Pilot Rig mirror machine, the first superconducting magnet facility to be used in plasma physics or fusion research; operation of the Superconducting Bumpy Torus magnet facility, first used to generate a toroidal magnetic field; steady state production of neutrons from DD reactions; studies of the direct conversion of plasma enthalpy to thrust by a direct fusion rocket via propellant addition and magnetic nozzles; power and propulsion system studies, including D(3)He power balance, neutron shielding, and refrigeration requirements; and development of large volume, high field superconducting and cryogenic magnet technology.

Superheavy nuclei from 48Ca-induced reactions

NASA Astrophysics Data System (ADS)

Oganessian, Yu. Ts.; Utyonkov, V. K.

2015-12-01

The discovery and investigation of the new region of superheavy nuclei at the DGFRS separator based on fusion reactions of 48Ca with 238U-249Cf target nuclei are reviewed. The production cross sections and summaries of the decay properties, including the results of the posterior experiments performed at the SHIP, BGS, and TASCA separators, as well as at the chemistry setups, are discussed and compared with the theoretical calculations and the systematic trends in the α-decay and spontaneous fission properties. The properties of the new nuclei, isotopes of elements 112-118, and their decay products demonstrate significant increases in the stability of the heaviest nuclei with increasing neutron number and closer approach to magic number N = 184.

Ignition and Inertial Confinement Fusion at The National Ignition Facility

NASA Astrophysics Data System (ADS)

Moses, Edward I.

2016-10-01

The National Ignition Facility (NIF), the world's largest and most powerful laser system for inertial confinement fusion (ICF) and for studying high-energy-density (HED) science, is now operational at Lawrence Livermore National Laboratory (LLNL). The NIF is now conducting experiments to commission the laser drive, the hohlraum and the capsule and to develop the infrastructure needed to begin the first ignition experiments in FY 2010. Demonstration of ignition and thermonuclear bum in the laboratory is a major NIF goal. NIF will achieve this by concentrating the energy from the 192 beams into a mm3-sized target and igniting a deuterium-tritium mix, liberating more energy than is required to initiate the fusion reaction. NIP's ignition program is a national effort managed via the National Ignition Campaign (NIC). The NIC has two major goals: execution of DT ignition experiments starting in FY20l0 with the goal of demonstrating ignition and a reliable, repeatable ignition platform by the conclusion of the NIC at the end of FY2012. The NIC will also develop the infrastructure and the processes required to operate NIF as a national user facility. The achievement of ignition at NIF will demonstrate the scientific feasibility of ICF and focus worldwide attention on laser fusion as a viable energy option. A laser fusion-based energy concept that builds on NIF, known as LIFE (Laser Inertial Fusion Energy), is currently under development. LIFE is inherently safe and can provide a global carbon-free energy generation solution in the 21st century. This paper describes recent progress on NIF, NIC, and the LIFE concept.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Walker, Johnnie A.; Takasuka, Taichi E.; Deng, Kai

Carbohydrate binding modules (CBMs) bind polysaccharides and help target glycoside hydrolases catalytic domains to their appropriate carbohydrate substrates. To better understand how CBMs can improve cellulolytic enzyme reactivity, representatives from each of the 18 families of CBM found in Ruminoclostridium thermocellum were fused to the multifunctional GH5 catalytic domain of CelE (Cthe_0797, CelEcc), which can hydrolyze numerous types of polysaccharides including cellulose, mannan, and xylan. Since CelE is a cellulosomal enzyme, none of these fusions to a CBM previously existed. CelEcc_CBM fusions were assayed for their ability to hydrolyze cellulose, lichenan, xylan, and mannan. Several CelEcc_CBM fusions showed enhanced hydrolyticmore » activity with different substrates relative to the fusion to CBM3a from the cellulosome scaffoldin, which has high affinity for binding to crystalline cellulose. Additional binding studies and quantitative catalysis studies using nanostructure-initiator mass spectrometry (NIMS) were carried out with the CBM3a, CBM6, CBM30, and CBM44 fusion enzymes. In general, and consistent with observations of others, enhanced enzyme reactivity was correlated with moderate binding affinity of the CBM. Numerical analysis of reaction time courses showed that CelEcc_CBM44, a combination of a multifunctional enzyme domain with a CBM having broad binding specificity, gave the fastest rates for hydrolysis of both the hexose and pentose fractions of ionic-liquid pretreated switchgrass. In conclusion, we have shown that fusions of different CBMs to a single multifunctional GH5 catalytic domain can increase its rate of reaction with different pure polysaccharides and with pretreated biomass. This fusion approach, incorporating domains with broad specificity for binding and catalysis, provides a new avenue to improve reactivity of simple combinations of enzymes within the complexity of plant biomass.« less

Laser-driven fusion etching process

DOEpatents

Ashby, C.I.H.; Brannon, P.J.; Gerardo, J.B.

1987-08-25

The surfaces of solids are etched by a radiation-driven chemical reaction. The process involves exposing a substrate coated with a layer of a reactant material on its surface to radiation, e.g., a laser, to induce localized melting of the substrate which results in the occurrence of a fusion reaction between the substrate and coating material. The resultant reaction product and excess reactant salt are then removed from the surface of the substrate with a solvent which is relatively inert towards the substrate. The laser-driven chemical etching process is especially suitable for etching ionic substrates, e.g., LiNbO/sub 3/, such as used in electro-optical/acousto-optic devices. It is also suitable for applications wherein the etching process is required to produce an etched ionic substrate having a smooth surface morphology or when a very rapid etching rate is desired.

Exploring the influence of transfer channels on fusion reactions: The case of 40 Ca + 58,64 Ni

DOE PAGES

Bourgin, D.; Courtin, S.; Haas, F.; ...

2015-01-29

Fusion cross sections have been measured in the 40Ca + 58Ni and 40Ca + 64Ni systems at beam energies ranging from E lab = 104.75 MeV to 153.5 MeV using the Laboratori Nazionali di Legnaro electrostatic deflector. Distributions of barriers have been extracted from the experimental data. Preliminary coupled channel calculations were performed and hints of effects of neutron transfers on the fusion below the barrier in the 40Ca + 64Ni are discussed.

Fission fragment yields from heavy-ion-induced reactions measured with a fragment separator

NASA Astrophysics Data System (ADS)

Tarasov, O. B.; Delaune, O.; Farget, F.; Morrissey, D. J.; Amthor, A. M.; Bastin, B.; Bazin, D.; Blank, B.; Cacéres, L.; Chbihi, A.; Fernández-Dominguez, B.; Grévy, S.; Kamalou, O.; Lukyanov, S. M.; Mittig, W.; Pereira, J.; Perrot, L.; Saint-Laurent, M.-G.; Savajols, H.; Sherrill, B. M.; Stodel, C.; Thomas, J. C.; Villari, A. C.

2018-04-01

The systematic study of fission fragment yields under different initial conditions has provided valuable experimental data for benchmarking models of fission product yields. Nuclear reactions using inverse kinematics coupled to the use of a high-resolution spectrometer with good fragment identification are shown here to be a powerful tool to measure the inclusive isotopic yields of fission fragments. In-flight fusion-fission was used in this work to produce secondary beams of neutron-rich isotopes in the collisions of a 238U beam at 24 MeV/u with 9Be and 12C targets at GANIL using the LISE3 fragment separator. Unique identification of the A, Z, and atomic charge state, q, of fission products was attained with the Δ E- TKE-B ρ- ToF measurement technique. Mass, and atomic number distributions are reported for the two reactions. The results show the importance of different reaction mechanisms in the two cases. The optimal target material for higher yields of neutron-rich high- Z isotopes produced in fusion-fission reactions as a function of projectile energy is discussed.

Active Neutron-Based Interrogation System with D-D Neutron Source for Detection of Special Nuclear Materials

NASA Astrophysics Data System (ADS)

Takahashi, Y.; Misawa, T.; Yagi, T.; Pyeon, C. H.; Kimura, M.; Masuda, K.; Ohgaki, H.

2015-10-01

The detection of special nuclear materials (SNM) is an important issue for nuclear security. The interrogation systems used in a sea port and an airport are developed in the world. The active neutron-based interrogation system is the one of the candidates. We are developing the active neutron-based interrogation system with a D-D fusion neutron source for the nuclear security application. The D-D neutron source is a compact discharge-type fusion neutron source called IEC (Inertial-Electrostatic Confinement fusion) device which provides 2.45 MeV neutrons. The nuclear materials emit the highenergy neutrons by fission reaction. High-energy neutrons with energies over 2.45 MeV amount to 30% of all the fission neutrons. By using the D-D neutron source, the detection of SNMs is considered to be possible with the attention of fast neutrons if there is over 2.45 MeV. Ideally, neutrons at En>2.45 MeV do not exist if there is no nuclear materials. The detection of fission neutrons over 2.45 MeV are hopeful prospect for the detection of SNM with a high S/N ratio. In the future, the experiments combined with nuclear materials and a D-D neutron source will be conducted. Furthermore, the interrogation system will be numerically investigated by using nuclear materials, a D-D neutron source, and a steel container.

Reactor experiments to study luminescence of He-Ne and He-Kr gaseous mixtures, excited by the products of 6Li (n, α) 3H nuclear reaction

NASA Astrophysics Data System (ADS)

Batyrbekov, E. G.; Gordienko, Yu. N.; Barsukov, N. I.; Ponkratov, Yu. V.; Kulsartov, T. V.; Khassenov, M. U.; Zaurbekova, Zh. A.; Tulubayev, Ye. Y.; Samarkhanov, K. K.

2018-04-01

The spectral studies of optical radiation of gaseous mixtures are of interest for solving problems associated with finding gaseous media with high energy conversion efficiency of nuclear reactions into the energy of laser or spontaneous emission [1, 2]. Such media can be used to extract energy from nuclear and fusion reactors in the form of optical radiation, and also to control and adjust the nuclear reactors parameters. This paper presents the preliminary results of the reactor experiments to study the spectral-luminescent properties of gas mixtures (based on He, Ne and Kr noble gases) excited by the products of 6Li(n,α)3H nuclear reaction at different levels of the stationary power of the IVG.1M reactor.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carbajal, L.; Warwick Univ., Coventry; Dendy, R. O.

Ion cyclotron emission (ICE) offers unique promise as a diagnostic of the fusion born alpha-particle population in magnetically confined plasmas. Pioneering observations from JET and TFTR found that ICE intensity P ICE scales approximately linearly with the measured neutron flux from fusion reactions, and with the inferred concentration, n /n i , of fusion-born alpha-particles confined within the plasma. We present fully nonlinear self-consistent kinetic simulations that reproduce this scaling for the first time. This resolves a longstanding question in the physics of fusion alpha particle confinement and stability in MCF plasmas. It confirms the MCI as the likely emissionmore » mechanism and greatly strengthens the basis for diagnostic exploitation of ICE in future burning plasmas.« less

Fusion power for space propulsion.

NASA Technical Reports Server (NTRS)

Roth, R.; Rayle, W.; Reinmann, J.

1972-01-01

Principles of operation, interplanetary orbit-to-orbit mission capabilities, technical problems, and environmental safeguards are examined for thermonuclear fusion propulsion systems. Two systems examined include (1) a fusion-electric concept in which kinetic energy of charged particles from the plasma is converted into electric power (for accelerating the propellant in an electrostatic thrustor) by the van de Graaf generator principle and (2) the direct fusion rocket in which energetic plasma lost from the reactor has a suitable amount of added propellant to obtain the optimum exhaust velocity. The deuterium-tritium and the deuterium/helium-3 reactions are considered as suitable candidates, and attention is given to problems of cryogenic refrigeration systems, magnet shielding, and high-energy particle extraction and guidance.

Systematic identification and analysis of frequent gene fusion events in metabolic pathways

DOE Office of Scientific and Technical Information (OSTI.GOV)

Henry, Christopher S.; Lerma-Ortiz, Claudia; Gerdes, Svetlana Y.

Here, gene fusions are the most powerful type of in silico-derived functional associations. However, many fusion compilations were made when <100 genomes were available, and algorithms for identifying fusions need updating to handle the current avalanche of sequenced genomes. The availability of a large fusion dataset would help probe functional associations and enable systematic analysis of where and why fusion events occur. As a result, here we present a systematic analysis of fusions in prokaryotes. We manually generated two training sets: (i) 121 fusions in the model organism Escherichia coli; (ii) 131 fusions found in B vitamin metabolism. These setsmore » were used to develop a fusion prediction algorithm that captured the training set fusions with only 7 % false negatives and 50 % false positives, a substantial improvement over existing approaches. This algorithm was then applied to identify 3.8 million potential fusions across 11,473 genomes. The results of the analysis are available in a searchable database. A functional analysis identified 3,000 reactions associated with frequent fusion events and revealed areas of metabolism where fusions are particularly prevalent. In conclusion, customary definitions of fusions were shown to be ambiguous, and a stricter one was proposed. Exploring the genes participating in fusion events showed that they most commonly encode transporters, regulators, and metabolic enzymes. The major rationales for fusions between metabolic genes appear to be overcoming pathway bottlenecks, avoiding toxicity, controlling competing pathways, and facilitating expression and assembly of protein complexes. Finally, our fusion dataset provides powerful clues to decipher the biological activities of domains of unknown function.« less

Systematic identification and analysis of frequent gene fusion events in metabolic pathways

DOE PAGES

Henry, Christopher S.; Lerma-Ortiz, Claudia; Gerdes, Svetlana Y.; ...

2016-06-24

Here, gene fusions are the most powerful type of in silico-derived functional associations. However, many fusion compilations were made when <100 genomes were available, and algorithms for identifying fusions need updating to handle the current avalanche of sequenced genomes. The availability of a large fusion dataset would help probe functional associations and enable systematic analysis of where and why fusion events occur. As a result, here we present a systematic analysis of fusions in prokaryotes. We manually generated two training sets: (i) 121 fusions in the model organism Escherichia coli; (ii) 131 fusions found in B vitamin metabolism. These setsmore » were used to develop a fusion prediction algorithm that captured the training set fusions with only 7 % false negatives and 50 % false positives, a substantial improvement over existing approaches. This algorithm was then applied to identify 3.8 million potential fusions across 11,473 genomes. The results of the analysis are available in a searchable database. A functional analysis identified 3,000 reactions associated with frequent fusion events and revealed areas of metabolism where fusions are particularly prevalent. In conclusion, customary definitions of fusions were shown to be ambiguous, and a stricter one was proposed. Exploring the genes participating in fusion events showed that they most commonly encode transporters, regulators, and metabolic enzymes. The major rationales for fusions between metabolic genes appear to be overcoming pathway bottlenecks, avoiding toxicity, controlling competing pathways, and facilitating expression and assembly of protein complexes. Finally, our fusion dataset provides powerful clues to decipher the biological activities of domains of unknown function.« less

CAPS drives trans-SNARE complex formation and membrane fusion through syntaxin interactions.

PubMed

James, Declan J; Kowalchyk, Judith; Daily, Neil; Petrie, Matt; Martin, Thomas F J

2009-10-13

Ca(2+)-dependent activator protein for secretion (CAPS) is an essential factor for regulated vesicle exocytosis that functions in priming reactions before Ca(2+)-triggered fusion of vesicles with the plasma membrane. However, the precise events that CAPS regulates to promote vesicle fusion are unclear. In the current work, we reconstituted CAPS function in a SNARE-dependent liposome fusion assay using VAMP2-containing donor and syntaxin-1/SNAP-25-containing acceptor liposomes. The CAPS stimulation of fusion required PI(4,5)P(2) in acceptor liposomes and was independent of Ca(2+), but Ca(2+) dependence was restored by inclusion of synaptotagmin. CAPS stimulated trans-SNARE complex formation concomitant with the stimulation of full membrane fusion at physiological SNARE densities. CAPS bound syntaxin-1, and CAPS truncations that competitively inhibited syntaxin-1 binding also inhibited CAPS-dependent fusion. The results revealed an unexpected activity of a priming protein to accelerate fusion by efficiently promoting trans-SNARE complex formation. CAPS may function in priming by organizing SNARE complexes on the plasma membrane.

Redistribution of fast ions during sawtooth reconnection

NASA Astrophysics Data System (ADS)

Jaulmes, F.; Westerhof, E.; de Blank, H. J.

2014-10-01

In a tokamak-based fusion power plant, possible scenarios may include regulated sawtooth oscillations to remove thermalized helium from the core of the plasma. During a sawtooth crash, the helium ash and other impurities trapped in the core are driven by the instability to an outer region. However, in a fusion plasma, high energy ions will represent a significant population. We thus study the behaviour of these energetic particles during a sawtooth. This paper presents the modelling of the redistribution of fast ions during a sawtooth reconnection event in a tokamak plasma. Along the lines of the model for the evolution of the flux surfaces during a sawtooth collapse described in Ya.I. Kolesnichenko and Yu.V. Yakovenko 1996 Nucl. Fusion 36 159, we have built a time-dependent electromagnetic model of a sawtooth reconnection. The trajectories of the ions are described by a complete gyro-orbit integration. The fast particles were evolved from specific initial parameters (given energy and uniform spread in pitch) or distributed initially according to a slowing-down distribution created by fusion reactions. Our modelling is used to understand the main equilibrium parameters driving the motions during the collapse and to determine the evolution of the distribution function of energetic ions when different geometries of reconnection are considered.

A single amino acid substitution modulates low-pH-triggered membrane fusion of GP64 protein in Autographa californica and Bombyx mori nucleopolyhedroviruses

DOE Office of Scientific and Technical Information (OSTI.GOV)

Katou, Yasuhiro; Yamada, Hayato; Ikeda, Motoko

2010-09-01

We have previously shown that budded viruses of Bombyx mori nucleopolyhedrovirus (BmNPV) enter the cell cytoplasm but do not migrate into the nuclei of non-permissive Sf9 cells that support a high titer of Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV) multiplication. Here we show, using the syncytium formation assay, that low-pH-triggered membrane fusion of BmNPV GP64 protein (Bm-GP64) is significantly lower than that of AcMNPV GP64 protein (Ac-GP64). Mutational analyses of GP64 proteins revealed that a single amino acid substitution between Ac-GP64 H155 and Bm-GP64 Y153 can have significant positive or negative effects on membrane fusion activity. Studies using bacmid-based GP64 recombinantmore » AcMNPV harboring point-mutated ac-gp64 and bm-gp64 genes showed that Ac-GP64 H155Y and Bm-GP64 Y153H substitutions decreased and increased, respectively, the multiplication and cell-to-cell spread of progeny viruses. These results indicate that Ac-GP64 H155 facilitates the low-pH-triggered membrane fusion reaction between virus envelopes and endosomal membranes.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, Huogen; Chen, Liang

Ti-Zr-Ni quasicrystals have been demonstrated to store a large number of hydrogen atoms, which implies strong potential application in hydrogen energy field for them. However, the desorption of hydrogen atoms in the quasicrystals is quite difficult, with the indication of high desorption temperature and slow desorption rate. The shortage limits their use in the field to a large extent. But this kind of quasicrystals might be used in nuclear fusion energy field, because tritium as a coral fuel for nuclear fusion needs tight storage. However, equilibrium pressure at room temperature of Ti-Zr-Ni quasicrystals, important for their application in fusion energymore » field, has not been clear yet. In this work, we designed a gas-solid reaction system with the pressure resolution of 10{sup −8}Pa and carried out hydrogen desorption investigation at different temperatures on Ti{sub 36}Zr{sub 40}Ni{sub 20}Pd{sub 4} icosahedral quasicrystal. Based on three Pressure-Composition-Temperature desorption curves, we speculate according to Van’t Hoff theory about hydrogen storage that its equilibrium pressure at room temperature could be at the magnitude of 10{sup −6}Pa, displaying good stability of hydrogen in the quasicrystal and also implying application prospects in fusion energy field for quasicrystals of this type.« less

Fusion proton diagnostic for the C-2 field reversed configurationa)

NASA Astrophysics Data System (ADS)

Magee, R. M.; Clary, R.; Korepanov, S.; Smirnov, A.; Garate, E.; Knapp, K.; Tkachev, A.

2014-11-01

Measurements of the flux of fusion products from high temperature plasmas provide valuable insights into the ion energy distribution, as the fusion reaction rate is a very sensitive function of ion energy. In C-2, where field reversed configuration plasmas are formed by the collision of two compact toroids and partially sustained by high power neutral beam injection [M. Binderbauer et al., Phys. Rev. Lett. 105, 045003 (2010); M. Tuszewski et al., Phys. Rev. Lett. 108, 255008 (2012)], measurements of DD fusion neutron flux are used to diagnose ion temperature and study fast ion confinement and dynamics. In this paper, we will describe the development of a new 3 MeV proton detector that will complement existing neutron detectors. The detector is a large area (50 cm2), partially depleted, ion implanted silicon diode operated in a pulse counting regime. While the scintillator-based neutron detectors allow for high time resolution measurements (˜100 kHz), they have no spatial or energy resolution. The proton detector will provide 10 cm spatial resolution, allowing us to determine if the axial distribution of fast ions is consistent with classical fast ion theory or whether anomalous scattering mechanisms are active. We will describe in detail the diagnostic design and present initial data from a neutral beam test chamber.

Effect of spin-polarized D-3He fuel on dense plasma focus for space propulsion

NASA Astrophysics Data System (ADS)

Mei-Yu Wang, Choi, Chan K.; Mead, Franklin B.

1992-01-01

Spin-polarized D-3He fusion fuel is analyzed to study its effect on the dense plasma focus (DPF) device for space propulsion. The Mather-type plasma focus device is adopted because of the ``axial'' acceleration of the current carrying plasma sheath, like a coaxial plasma gun. The D-3He fuel is chosen based on the neutron-lean fusion reactions with high charged-particle fusion products. Impulsive mode of operation is used with multi-thrusters in order to make higher thrust (F)-to-weight (W) ratio with relatively high value of specific impulse (Isp). Both current (I) scalings with I2 and I8/3 are considered for plasma pinch temperature and capacitor mass. For a 30-day Mars mission, with four thrusters, for example, the typical F/W values ranging from 0.5-0.6 to 0.1-0.2 for I2 and I8/3 scalings, respectively, and the Isp values of above 1600 s are obtained. Parametric studies indicate that the spin-polarized D-3He provides increased values of F/W and Isp over conventional D-3He fuel which was due to the increased fusion power and decreased radiation losses for the spin-polarized case.

Radiation reaction in fusion plasmas.

PubMed

Hazeltine, R D; Mahajan, S M

2004-10-01

The effects of a radiation reaction on thermal electrons in a magnetically confined plasma, with parameters typical of planned burning plasma experiments, are studied. A fully relativistic kinetic equation that includes the radiation reaction is derived. The associated rate of phase-space contraction is computed and the relative importance of the radiation reaction in phase space is estimated. A consideration of the moments of the radiation reaction force show that its effects are typically small in reactor-grade confined plasmas, but not necessarily insignificant.

Rapid heating of matter using high power lasers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bang, Woosuk

2016-04-08

This slide presentation describes motivation (uniform and rapid heating of a target, opportunity to study warm dense matter, study of nuclear fusion reactions), rapid heating of matter with intense laser-driven ion beams, visualization of the expanding warm dense gold and diamond, and nuclear fusion experiments using high power lasers (direct heating of deuterium spheres (radius ~ 10nm) with an intense laser pulse.

Using multiple secondary fusion products to evaluate fuel ρR, electron temperature, and mix in deuterium-filled implosions at the NIF

DOE PAGES

Rinderknecht, H. G.; Rosenberg, M. J.; Zylstra, A. B.; ...

2015-08-25

In deuterium-filled inertial confinement fusion implosions, the secondary fusion processes D( 3He,p) 4He and D(T,n) 4He occur, as the primary fusion products 3He and T react in flight with thermal deuterons. In implosions with moderate fuel areal density (~ 5–100 mg/cm 2), the secondary D- 3He reaction saturates, while the D-T reaction does not, and the combined information from these secondary products is used to constrain both the areal density and either the plasma electron temperature or changes in the composition due to mix of shell material into the fuel. The underlying theory of this technique is developed and appliedmore » to three classes of implosions on the National Ignition Facility: direct-drive exploding pushers, indirect-drive 1-shock and 2-shock implosions,and polar direct-drive implosions. In the 1- and 2-shock implosions, the electron temperature is inferred to be 0.65 x and 0.33 x the burn-averaged ion temperature, respectively. The inferred mixed mass in the polar direct-drive implosions is in agreement with measurements using alternative techniques.« less

Microstructural Evolution of INCONEL® Alloy 740H® Fusion Welds During Creep

NASA Astrophysics Data System (ADS)

Bechetti, Daniel H.; DuPont, John N.; de Barbadillo, John J.; Baker, Brian A.; Watanabe, Masashi

2015-02-01

Electron microscopy techniques have been used to investigate the cause of premature creep failure in the fusion zone of INCONEL® Alloy 740H® (INCONEL and 740H are registered trademarks of Special Metals Corporation) welds. The reduced creep rupture lives of all-weld-metal and cross-weld creep specimens (relative to base metal specimens) have been attributed to the presence of large grain boundary regions that were denuded in fine γ' but contained coarse, elongated particles. Investigation of creep rupture specimens has revealed four factors that influence the formation of these coarsened zones, and the large particles found within them have been identified as γ'. Comparisons of the microstructural characteristics of these zones to the characteristics that are typical of denuded zones formed by a variety of mechanisms identified in the literature have been made. It is concluded that the mechanism of γ'-denuded zone formation in alloy 740H is discontinuous coarsening of the γ' phase. The discontinuous reaction is catalyzed by the grain boundary migration and sliding which occur during creep and likely promoted by the inhomogeneous weld metal microstructure that results from solute segregation during solidification. The increased susceptibility to the formation of the observed γ'-denuded zones in the weld metal as compared to the base metal is discussed in the context of differences in the contributions to the driving force for the discontinuous coarsening reaction.

Simulation and Analysis of Isotope Separation System for Fusion Fuel Recovery System

NASA Astrophysics Data System (ADS)

Senevirathna, Bathiya; Gentile, Charles

2011-10-01

This paper presents results of a simulation of the Fuel Recovery System (FRS) for the Laser Inertial Fusion Engine (LIFE) reactor. The LIFE reaction will produce exhaust gases that will need to be recycled in the FRS along with xenon, the chamber's intervention gas. Solids and liquids will first be removed and then vapor traps are used to remove large gas molecules such as lead. The gas will be reacted with lithium at high temperatures to extract the hydrogen isotopes, protium, deuterium, and tritium in hydride form. The hydrogen isotopes will be recovered using a lithium blanket processing system already in place and this product will be sent to the Isotope Separation System (ISS). The ISS will be modeled in software to analyze its effectiveness. Aspen HYSYS was chosen for this purpose for its widespread use industrial gas processing systems. Reactants and corresponding chemical reactions had to be initialized in the software. The ISS primarily consists of four cryogenic distillation columns and these were modeled in HYSYS based on design requirements. Fractional compositions of the distillate and liquid products were analyzed and used to optimize the overall system.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hora, H.; Korn, G.; Eliezer, S.

Measured highly elevated gains of proton–boron (HB11) fusion (Picciottoet al., Phys. Rev. X4, 031030 (2014)) confirmed the exceptional avalanche reaction process (Lalousiset al., Laser Part. Beams 32, 409 (2014); Horaet al., Laser Part. Beams33, 607 (2015)) for the combination of the non-thermal block ignition using ultrahigh intensity laser pulses of picoseconds duration. The ultrahigh accelerationabovemore » $$10^{20}~\\text{cm}~\\text{s}^{-2}$$ for plasma blocks was theoretically and numerically predicted since 1978 (Hora,Physics of Laser Driven Plasmas(Wiley, 1981), pp. 178 and 179) and measured (Sauerbrey, Phys. Plasmas3, 4712 (1996)) in exact agreement (Horaet al., Phys. Plasmas14, 072701 (2007)) when the dominating force was overcoming thermal processes. This is based on Maxwell’s stress tensor by the dielectric properties of plasma leading to the nonlinear (ponderomotive) force $$f_{\\text{NL}}$$ resulting in ultra-fast expanding plasma blocks by a dielectric explosion. Combining this with measured ultrahigh magnetic fields and the avalanche process opens an option for an environmentally absolute clean and economic boron fusion power reactor. Finally, this is supported also by other experiments with very high HB11 reactions under different conditions (Labauneet al., Nature Commun.4, 2506 (2013)).« less

Low Activation Joining of SiC/SiC Composites for Fusion Applications: Modeling Miniature Torsion Tests

DOE Office of Scientific and Technical Information (OSTI.GOV)

Henager, Charles H.; Nguyen, Ba Nghiep; Kurtz, Richard J.

2014-06-30

The use of SiC and SiC-composites in fission or fusion environments appears to require joining methods for assembling systems. The international fusion community has designed miniature torsion specimens for joint testing and for irradiation in HFIR. Therefore, miniature torsion joints were fabricated using displacement reactions between Si and TiC to produce Ti3SiC2 + SiC joints with CVD-SiC that were tested in shear prior to and after HFIR irradiation. However, these torsion specimens fail out-of-plane, which causes difficulties in determining a shear strength for the joints or for comparing unirradiated and irradiated joints. A finite element damage model has been developedmore » that indicates fracture is likely to occur within the joined pieces to cause out-of-plane failures for miniature torsion specimens when a certain modulus and strength ratio between the joint material and the joined material exists. The implications for torsion shear joint data based on this sample design are discussed.« less

Selective preparation of zeolite X and A from flyash and its use as catalyst for biodiesel production.

PubMed

Volli, Vikranth; Purkait, M K

2015-10-30

This work discusses the utilization of flyash for synthesis of heterogeneous catalyst for transesterification. Different types of zeolites were synthesized from alkali fusion followed by hydrothermal treatment of coal flyash as source material. The synthesis conditions were optimized to obtain highly crystalline zeolite based on degree of crystallinity and cation exchange capacity (CEC). The effect of CEC, acid treatment, Si/Al ratio and calcination temperature (800, 900 and 1000 °C) on zeolite formation was also studied. Pure, single phase and highly crystalline zeolite was obtained at flyash/NaOH ratio (1:1.2), fusion temperature (550 °C), fusion time (1 h), hydrothermal temperature (110 °C) and hydrothermal time (12h). The synthesized zeolite was ion-exchanged with potassium and was used as catalyst for transesterification of mustard oil to obtain a maximum conversion of 84.6% with 5 wt% catalyst concentration, 12:1 methanol to oil molar ratio, reaction time of 7 h at 65 °C. The catalyst was reused for 3 times with marginal reduction in activity. Copyright © 2015 Elsevier B.V. All rights reserved.

Low Energy Nuclear Reactions: 2007 Update

NASA Astrophysics Data System (ADS)

Krivit, Steven B.

2007-03-01

This paper presents an overview of low energy nuclear reactions, a subset of the field of condensed matter nuclear science. Condensed matter nuclear science studies nuclear effects in and/or on condensed matter, including low energy nuclear reactions, an entirely new branch of science that gained widespread attention and notoriety beginning in 1989 with the announcement of a previously unrecognized source of energy by Martin Fleischmann and Stanley Pons that came to be known as cold fusion. Two branches of LENR are recognized. The first includes a set of reactions like those observed by Fleischmann and Pons that use palladium and deuterium and yield excess heat and helium-4. Numerous mechanisms have been proposed to explain these reactions, however there is no consensus for, or general acceptance of, any of the theories. The claim of fusion is still considered speculative and, as such, is not an ideal term for this work. The other branch is a wide assortment of nuclear reactions that may occur with either hydrogen or deuterium. Anomalous nuclear transmutations are reported that involve light as well as heavy elements. The significant questions that face this field of research are: 1) Are LENRs a genuine nuclear reaction? 2) If so, is there a release of excess energy? 3) If there is, is the energy release cost-effective?

An in situ accelerator-based diagnostic for plasma-material interactions science on magnetic fusion devices.

PubMed

Hartwig, Zachary S; Barnard, Harold S; Lanza, Richard C; Sorbom, Brandon N; Stahle, Peter W; Whyte, Dennis G

2013-12-01

This paper presents a novel particle accelerator-based diagnostic that nondestructively measures the evolution of material surface compositions inside magnetic fusion devices. The diagnostic's purpose is to contribute to an integrated understanding of plasma-material interactions in magnetic fusion, which is severely hindered by a dearth of in situ material surface diagnosis. The diagnostic aims to remotely generate isotopic concentration maps on a plasma shot-to-shot timescale that cover a large fraction of the plasma-facing surface inside of a magnetic fusion device without the need for vacuum breaks or physical access to the material surfaces. Our instrument uses a compact (~1 m), high-current (~1 milliamp) radio-frequency quadrupole accelerator to inject 0.9 MeV deuterons into the Alcator C-Mod tokamak at MIT. We control the tokamak magnetic fields--in between plasma shots--to steer the deuterons to material surfaces where the deuterons cause high-Q nuclear reactions with low-Z isotopes ~5 μm into the material. The induced neutrons and gamma rays are measured with scintillation detectors; energy spectra analysis provides quantitative reconstruction of surface compositions. An overview of the diagnostic technique, known as accelerator-based in situ materials surveillance (AIMS), and the first AIMS diagnostic on the Alcator C-Mod tokamak is given. Experimental validation is shown to demonstrate that an optimized deuteron beam is injected into the tokamak, that low-Z isotopes such as deuterium and boron can be quantified on the material surfaces, and that magnetic steering provides access to different measurement locations. The first AIMS analysis, which measures the relative change in deuterium at a single surface location at the end of the Alcator C-Mod FY2012 plasma campaign, is also presented.

Neutron imaging with bubble chambers for inertial confinement fusion

NASA Astrophysics Data System (ADS)

Ghilea, Marian C.

One of the main methods to obtain energy from controlled thermonuclear fusion is inertial confinement fusion (ICF), a process where nuclear fusion reactions are initiated by heating and compressing a fuel target, typically in the form of a pellet that contains deuterium and tritium, relying on the inertia of the fuel mass to provide confinement. In inertial confinement fusion experiments, it is important to distinguish failure mechanisms of the imploding capsule and unambiguously diagnose compression and hot spot formation in the fuel. Neutron imaging provides such a technique and bubble chambers are capable of generating higher resolution images than other types of neutron detectors. This thesis explores the use of a liquid bubble chamber to record high yield 14.1 MeV neutrons resulting from deuterium-tritium fusion reactions on ICF experiments. A design tool to deconvolve and reconstruct penumbral and pinhole neutron images was created, using an original ray tracing concept to simulate the neutron images. The design tool proved that misalignment and aperture fabrication errors can significantly decrease the resolution of the reconstructed neutron image. A theoretical model to describe the mechanism of bubble formation was developed. A bubble chamber for neutron imaging with Freon 115 as active medium was designed and implemented for the OMEGA laser system. High neutron yields resulting from deuterium-tritium capsule implosions were recorded. The bubble density was too low for neutron imaging on OMEGA but agreed with the model of bubble formation. The research done in here shows that bubble detectors are a promising technology for the higher neutron yields expected at National Ignition Facility (NIF).

Binaural fusion and listening effort in children who use bilateral cochlear implants: a psychoacoustic and pupillometric study.

PubMed

Steel, Morrison M; Papsin, Blake C; Gordon, Karen A

2015-01-01

Bilateral cochlear implants aim to provide hearing to both ears for children who are deaf and promote binaural/spatial hearing. Benefits are limited by mismatched devices and unilaterally-driven development which could compromise the normal integration of left and right ear input. We thus asked whether children hear a fused image (ie. 1 vs 2 sounds) from their bilateral implants and if this "binaural fusion" reduces listening effort. Binaural fusion was assessed by asking 25 deaf children with cochlear implants and 24 peers with normal hearing whether they heard one or two sounds when listening to bilaterally presented acoustic click-trains/electric pulses (250 Hz trains of 36 ms presented at 1 Hz). Reaction times and pupillary changes were recorded simultaneously to measure listening effort. Bilaterally implanted children heard one image of bilateral input less frequently than normal hearing peers, particularly when intensity levels on each side were balanced. Binaural fusion declined as brainstem asymmetries increased and age at implantation decreased. Children implanted later had access to acoustic input prior to implantation due to progressive deterioration of hearing. Increases in both pupil diameter and reaction time occurred as perception of binaural fusion decreased. Results indicate that, without binaural level cues, children have difficulty fusing input from their bilateral implants to perceive one sound which costs them increased listening effort. Brainstem asymmetries exacerbate this issue. By contrast, later implantation, reflecting longer access to bilateral acoustic hearing, may have supported development of auditory pathways underlying binaural fusion. Improved integration of bilateral cochlear implant signals for children is required to improve their binaural hearing.

Synergism of He-3 acquisition with lunar base evolution

NASA Technical Reports Server (NTRS)

Crabb, T. M.; Jacobs, M. K.

1992-01-01

Researchers have discovered that the lunar surface contains a valuable fusion fuel element that is relatively scarce on Earth. This element, He-3, originates from the solar wind that has bombarded the surface of the Moon over geologic time. Mining operations to recover this resource would allow the by-product acquisition of hydrogen, water, carbon dioxide, carbon monoxide, methane, and nitrogen from the lunar surface with relatively minimal additional resource investment when compared to the costs to supply these resources from Earth. Two configurations for the He-3 mining system are discussed, and the impacts of these mining operations on a projected lunar base scenario are assessed. We conclude that the acquisition of He-3 is feasible with minimal advances in current state-of-the-art technologies and could support a terrestrial nuclear fusion power economy with the lowest hazard risk of any nuclear reaction known. Also, the availability of the by-products of He-3 acquisition from the Moon could significantly reduce the operational requirements of a lunar base and increase the commercialization potential of the base through consumable resupply of the lunar base itself, other components of the space infrastructure, and other space missions.

Semiclassical treatment of fusion and breakup processes of ^{6,8}He halo nuclei

NASA Astrophysics Data System (ADS)

Majeed, Fouad A.; Abdul-Hussien, Yousif A.

2016-06-01

A semiclassical approach has been used to study the effect of channel coupling on the calculations of the total fusion reaction cross section σ _{fus}, and the fusion barrier distribution D_{fus} for the systems 6He +^{238}U and 8He +^{197}Au. Since these systems invloves light exotic nuclei, breakup states channel play an important role that should be considered in the calculations. In semiclassical treatment, the relative motion between the projectile and target nuclei is approximated by a classical trajectory while the intrinsic dynamics is handled by time-dependent quantum mechanics. The calculations of the total fusion cross section σ _{fus}, and the fusion barrier distribution D_{fus} are compared with the full quantum mechanical calculations using the coupled-channels calculations with all order coupling using the computer code and with the available experimental data.

Heavy residues from very mass asymmetric heavy ion reactions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hanold, Karl Alan

1994-08-01

The isotopic production cross sections and momenta of all residues with nuclear charge (Z) greater than 39 from the reaction of 26, 40, and 50 MeV/nucleon 129Xe + Be, C, and Al were measured. The isotopic cross sections, the momentum distribution for each isotope, and the cross section as a function of nuclear charge and momentum are presented here. The new cross sections are consistent with previous measurements of the cross sections from similar reaction systems. The shape of the cross section distribution, when considered as a function of Z and velocity, was found to be qualitatively consistent with thatmore » expected from an incomplete fusion reaction mechanism. An incomplete fusion model coupled to a statistical decay model is able to reproduce many features of these reactions: the shapes of the elemental cross section distributions, the emission velocity distributions for the intermediate mass fragments, and the Z versus velocity distributions. This model gives a less satisfactory prediction of the momentum distribution for each isotope. A very different model based on the Boltzman-Nordheim-Vlasov equation and which was also coupled to a statistical decay model reproduces many features of these reactions: the shapes of the elemental cross section distributions, the intermediate mass fragment emission velocity distributions, and the Z versus momentum distributions. Both model calculations over-estimate the average mass for each element by two mass units and underestimate the isotopic and isobaric widths of the experimental distributions. It is shown that the predicted average mass for each element can be brought into agreement with the data by small, but systematic, variation of the particle emission barriers used in the statistical model. The predicted isotopic and isobaric widths of the cross section distributions can not be brought into agreement with the experimental data using reasonable parameters for the statistical model.« less

Commercial objectives, technology transfer, and systems analysis for fusion power development

NASA Astrophysics Data System (ADS)

Dean, Stephen O.

1988-03-01

Fusion is an essentially inexhaustible source of energy that has the potential for economically attractive commercial applications with excellent safety and environmental characteristics. The primary focus for the fusion-energy development program is the generation of centralstation electricity. Fusion has the potential, however, for many other applications. The fact that a large fraction of the energy released in a DT fusion reaction is carried by high-energy neutrons suggests potentially unique applications. These include breeding of fissile fuels, production of hydrogen and other chemical products, transmutation or “burning” of various nuclear or chemical wastes, radiation processing of materials, production of radioisotopes, food preservation, medical diagnosis and medical treatment, and space power and space propulsion. In addition, fusion R&D will lead to new products and new markets. Each fusion application must meet certain standards of economic and safety and environmental attractiveness. For this reason, economics on the one hand, and safety and environment and licensing on the other hand, are the two primary criteria for setting long-range commercial fusion objectives. A major function of systems analysis is to evaluate the potential of fusion against these objectives and to help guide the fusion R&D program toward practical applications. The transfer of fusion technology and skills from the national laboratories and universities to industry is the key to achieving the long-range objective of commercial fusion applications.

Effect of nuclear-reaction mechanisms on the population of excited nuclear states and isomeric ratios

DOE Office of Scientific and Technical Information (OSTI.GOV)

Skobelev, N. K., E-mail: skobelev@jinr.ru

2016-07-15

Experimental data on the cross sections for channels of fusion and transfer reactions induced by beams of radioactive halo nuclei and clustered and stable loosely bound nuclei were analyzed, and the results of this analysis were summarized. The interplay of the excitation of single-particle states in reaction-product nuclei and direct reaction channels was established for transfer reactions. Respective experiments were performed in stable ({sup 6}Li) and radioactive ({sup 6}He) beams of the DRIBs accelerator complex at the Flerov Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research, and in deuteron and {sup 3}He beams of the U-120M cyclotron at themore » Nuclear Physics Institute, Academy Sciences of Czech Republic (Řež and Prague, Czech Republic). Data on subbarrier and near-barrier fusion reactions involving clustered and loosely bound light nuclei ({sup 6}Li and {sup 3}He) can be described quite reliably within simple evaporation models with allowance for different reaction Q-values and couple channels. In reactions involving halo nuclei, their structure manifests itself most strongly in the region of energies below the Coulomb barrier. Neutron transfer occurs with a high probability in the interactions of all loosely bound nuclei with light and heavy stable nuclei at positive Q-values. The cross sections for such reactions and the respective isomeric ratios differ drastically for nucleon stripping and nucleon pickup mechanisms. This is due to the difference in the population probabilities for excited single-particle states.« less

Status of cold fusion (2010)

NASA Astrophysics Data System (ADS)

Storms, Edmund

2010-10-01

The phenomenon called cold fusion has been studied for the last 21 years since its discovery by Profs. Fleischmann and Pons in 1989. The discovery was met with considerable skepticism, but supporting evidence has accumulated, plausible theories have been suggested, and research is continuing in at least eight countries. This paper provides a brief overview of the major discoveries and some of the attempts at an explanation. The evidence supports the claim that a nuclear reaction between deuterons to produce helium can occur in special materials without application of high energy. This reaction is found to produce clean energy at potentially useful levels without the harmful byproducts normally associated with a nuclear process. Various requirements of a model are examined.

Experimental search for the radiative capture reaction d + d {yields} {sup 4}He + {gamma} from the dd{mu} muonic molecule state J = 1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baluev, V. V.; Bogdanova, L. N.; Bom, V. R.

2011-07-15

A search for the muon-catalyzed fusion reaction d + d {yields} {sup 4}He + {gamma} in the dd{mu} muonic molecule was performed using the experimental installation TRITON with BGO detectors for {gamma}-quanta. A high-pressure target filled with deuterium was exposed to the negative muon beam of the JINR Phasotron to detect {gamma}-quanta with the energy 23.8 MeV. An experimental estimation for the yield of radiative deuteron capture from the dd{mu} state J = 1 was obtained at the level of {eta}{sub {gamma}} {<=} 8 Multiplication-Sign 10{sup -7} per fusion.

Status of cold fusion (2010).

PubMed

Storms, Edmund

2010-10-01

The phenomenon called cold fusion has been studied for the last 21 years since its discovery by Profs. Fleischmann and Pons in 1989. The discovery was met with considerable skepticism, but supporting evidence has accumulated, plausible theories have been suggested, and research is continuing in at least eight countries. This paper provides a brief overview of the major discoveries and some of the attempts at an explanation. The evidence supports the claim that a nuclear reaction between deuterons to produce helium can occur in special materials without application of high energy. This reaction is found to produce clean energy at potentially useful levels without the harmful byproducts normally associated with a nuclear process. Various requirements of a model are examined.

Fusion and elastic scattering of 6Li + 58Ni at low energies

NASA Astrophysics Data System (ADS)

Aguilera, Elí F.; Amador-Valenzuela, Paulina; Martinez-Quiroz, Enrique; Lizcano, David; Garcia-Flores, Araceli; Kolata, James J.

2017-11-01

Sub-barrier fusion cross sections (σfus) for the 6Li + 58Ni system, obtained from the respective evaporation protons, are examined in the present work. With respect to expectations of a simple one-dimensional barrier penetration model, a large enhancement of the data is observed. Good consistency with equivalent data reported previously for similar systems is found. A comparison with total reaction cross sections (σR), deduced from elastic scattering measurements reported previously, indicates that σfus is close to σR within the measured energy range. To estimate the contribution of complete fusion (CF), an optical model analysis of the elastic scattering data is performed where CF is identified with the absorption in a short range volume potential. A surface polarization potential is added to the bare nuclear potential to simulate the effect of peripheral reactions. The results obtained indicate that other mechanisms different from CF may be dominant, especially in the lower energy region.

Jupiter - Solid or Gaseous? Ask Juno

NASA Astrophysics Data System (ADS)

Ackerman, J. A., Jr.

2015-12-01

Data from Cassini, Galileo, S-L 9 and Ulysses suggest Jupiter and Saturn are solid, frozen, Methane Gas Hydrate (MGH) planets. The bulk of these giants formed slow and cold by the natural accretion of snowflakes at their current orbital radii in the presence of methane, forming rigid incompressible bodies. MGH, (CH4)8(H2O)46 (d=0.9), is consistent with the abundances of the elements comprising the Earth (H>O>C). Their combined MGH comprises >250 earth-masses of H2O. Jupiter (d=1.33) incorporated most of the heavy elements in the nascent solar system, exemplified by an enormously enhanced D/H. The temperature excess of Jupiter's atmosphere is the result of an impact ~6,000 years BP, triggering an incredibly energetic fusion explosion which ejected the masses of the proto-Galilean moons. It also initiated a continuing fusion furnace in the crater producing a jet of hot gases extending >2x106 km, beyond Callisto. The jet has slowly diminished over 6,000 years, resulting in the differences in the four Galilean Moons. The mass ejection (ang. mom.) slowed Jupiter's rotation until ~1930, currently interpreted as a drift of the Great Red Spot. A diminishing fusion reaction (D + p → 3He + γ) continues to this day, producing Jupiter's atmospheric 'temperature excess'. Jupiter's rapid rotation deflects the rising vortex of hot gases from the fusion reaction horizontally, driving multiple zonal vortices, constrained by the frozen MGH surface <1000 km below the cloud tops. It appears as the tilted Great Red Spot (GRS), ~30,000 km to the west of the crater at 22 o S Lat., which has remained unchanged in the last 350 years - impossible due to the enormous Coliolis effect. Streams of 3He produced in the fusion reaction exiting Jupiter through the center of the GRS have been detected by the Galileo probe and orbiter, Ulysses, and Cassini. The fusion releases methane, also heavy elements which oxidize as they rise, producing the cloud-top colors. The MGH hypothesis explains the >6 minute delays of the larger S-L 9 'main events' as the time required for the mushroom clouds from their impacts to reach the cloud tops. The Juno MWR can potentially detect the fusion source and certainly the hot, longitudinally extended column forming the GRS. The Gravity Experiment should detect the basin in which it is located, possibly others.

Production of thin targets by implantation for the measurement of the 16O + 16O elastic scattering below the Coulomb barrier

NASA Astrophysics Data System (ADS)

Silva, H.; Cruz, J.; Sánchez-Benítez, A. M.; Santos, C.; Luís, H.; Fonseca, M.; Jesus, A. P.

2017-09-01

In recent decades, the processes of fusion of 16O were studied both theoretically and experimentally. However, the theoretical calculations are unable to fit both elastic scattering cross sections and fusion S-factors. The use of 16O thin transmission targets is required to measure the elastic forward scattering 16O + 16O reaction. The areal density of the target must be high to maximize the reaction products yields, but not so high as to allow a correct calculation of the effective beam energy. Besides this, the target must withstand beam interactions without noticeable deterioration, and contaminants must be minimal. In this study, the production of thin targets is performed with an innovative technique. Beam characterization and preliminary spectrum for the elastic scattering are also presented, showing the suitability of these targets for the proposed reaction.

Laser-driven fusion etching process

DOEpatents

Ashby, Carol I. H.; Brannon, Paul J.; Gerardo, James B.

1989-01-01

The surfaces of solid ionic substrates are etched by a radiation-driven chemical reaction. The process involves exposing an ionic substrate coated with a layer of a reactant material on its surface to radiation, e.g. a laser, to induce localized melting of the substrate which results in the occurrance of a fusion reaction between the substrate and coating material. The resultant reaction product and excess reactant salt are then removed from the surface of the substrate with a solvent which is relatively inert towards the substrate. The laser-driven chemical etching process is especially suitable for etching ionic salt substrates, e.g., a solid inorganic salt such as LiNbO.sub.3, such as used in electro-optical/acousto-optic devices. It is also suitable for applications wherein the etching process is required to produce an etched ionic substrate having a smooth surface morphology or when a very rapid etching rate is desired.

Magnetic-confinement fusion

NASA Astrophysics Data System (ADS)

Ongena, J.; Koch, R.; Wolf, R.; Zohm, H.

2016-05-01

Our modern society requires environmentally friendly solutions for energy production. Energy can be released not only from the fission of heavy nuclei but also from the fusion of light nuclei. Nuclear fusion is an important option for a clean and safe solution for our long-term energy needs. The extremely high temperatures required for the fusion reaction are routinely realized in several magnetic-fusion machines. Since the early 1990s, up to 16 MW of fusion power has been released in pulses of a few seconds, corresponding to a power multiplication close to break-even. Our understanding of the very complex behaviour of a magnetized plasma at temperatures between 150 and 200 million °C surrounded by cold walls has also advanced substantially. This steady progress has resulted in the construction of ITER, a fusion device with a planned fusion power output of 500 MW in pulses of 400 s. ITER should provide answers to remaining important questions on the integration of physics and technology, through a full-size demonstration of a tenfold power multiplication, and on nuclear safety aspects. Here we review the basic physics underlying magnetic fusion: past achievements, present efforts and the prospects for future production of electrical energy. We also discuss questions related to the safety, waste management and decommissioning of a future fusion power plant.

Deep-inelastic multinucleon transfer processes in the 16O+27Al reaction

NASA Astrophysics Data System (ADS)

Roy, B. J.; Sawant, Y.; Patwari, P.; Santra, S.; Pal, A.; Kundu, A.; Chattopadhyay, D.; Jha, V.; Pandit, S. K.; Parkar, V. V.; Ramachandran, K.; Mahata, K.; Nayak, B. K.; Saxena, A.; Kailas, S.; Nag, T. N.; Sahoo, R. N.; Singh, P. P.; Sekizawa, K.

2018-03-01

The reaction mechanism of deep-inelastic multinucleon transfer processes in the 16O+27Al reaction at an incident 16O energy (Elab=134 MeV) substantially above the Coulomb barrier has been studied both experimentally and theoretically. Elastic-scattering angular distribution, total kinetic energy loss spectra, and angular distributions for various transfer channels have been measured. The Q -value- and angle-integrated isotope production cross sections have been deduced. To obtain deeper insight into the underlying reaction mechanism, we have carried out a detailed analysis based on the time-dependent Hartree-Fock (TDHF) theory. A recently developed method, TDHF+GEMINI, has been applied to evaluate production cross sections for secondary products. From a comparison between the experimental and theoretical cross sections, we find that the theory qualitatively reproduces the experimental data. Significant effects of secondary light-particle emissions are demonstrated. Possible interplay among fusion-fission, deep-inelastic, multinucleon transfer, and particle evaporation processes is discussed.

Research on anisotropy of fusion-produced protons and neutrons emission from high-current plasma-focus discharges.

PubMed

Malinowski, K; Skladnik-Sadowska, E; Sadowski, M J; Szydlowski, A; Czaus, K; Kwiatkowski, R; Zaloga, D; Paduch, M; Zielinska, E

2015-01-01

The paper concerns fast protons and neutrons from D-D fusion reactions in a Plasma-Focus-1000U facility. Measurements were performed with nuclear-track detectors arranged in "sandwiches" of an Al-foil and two PM-355 detectors separated by a polyethylene-plate. The Al-foil eliminated all primary deuterons, but was penetrable for fast fusion protons. The foil and first PM-355 detector were penetrable for fast neutrons, which were converted into recoil-protons in the polyethylene and recorded in the second PM-355 detector. The "sandwiches" were irradiated by discharges of comparable neutron-yields. Analyses of etched tracks and computer simulations of the fusion-products behavior in the detectors were performed.

Simulation of Fusion Plasmas

ScienceCinema

Holland, Chris [UC San Diego, San Diego, California, United States

2017-12-09

The upcoming ITER experiment (www.iter.org) represents the next major milestone in realizing the promise of using nuclear fusion as a commercial energy source, by moving into the “burning plasma” regime where the dominant heat source is the internal fusion reactions. As part of its support for the ITER mission, the US fusion community is actively developing validated predictive models of the behavior of magnetically confined plasmas. In this talk, I will describe how the plasma community is using the latest high performance computing facilities to develop and refine our models of the nonlinear, multiscale plasma dynamics, and how recent advances in experimental diagnostics are allowing us to directly test and validate these models at an unprecedented level.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gruenwald, J., E-mail: johannes.gruenwald@inp-greifswald.de; Fröhlich, M.

A model of the behavior of transit time instabilities in an electrostatic confinement fusion reactor is presented in this letter. It is demonstrated that different modes are excited within the spherical cathode of a Farnsworth fusor. Each of these modes is dependent on the fusion products as well as the acceleration voltage applied between the two electrodes and they couple to a resulting oscillation showing non-linear beat phenomena. This type of instability is similar to the transit time instability of electrons between two resonant surfaces but the presence of ions and the occurring fusion reactions alter the physics of thismore » instability considerably. The physics of this plasma instability is examined in detail for typical physical parameter ranges of electrostatic confinement fusion devices.« less

Research on anisotropy of fusion-produced protons and neutrons emission from high-current plasma-focus discharges

DOE Office of Scientific and Technical Information (OSTI.GOV)

Malinowski, K., E-mail: karol.malinowski@ncbj.gov.pl; Sadowski, M. J.; Szydlowski, A.

2015-01-15

The paper concerns fast protons and neutrons from D-D fusion reactions in a Plasma-Focus-1000U facility. Measurements were performed with nuclear-track detectors arranged in “sandwiches” of an Al-foil and two PM-355 detectors separated by a polyethylene-plate. The Al-foil eliminated all primary deuterons, but was penetrable for fast fusion protons. The foil and first PM-355 detector were penetrable for fast neutrons, which were converted into recoil-protons in the polyethylene and recorded in the second PM-355 detector. The “sandwiches” were irradiated by discharges of comparable neutron-yields. Analyses of etched tracks and computer simulations of the fusion-products behavior in the detectors were performed.

Health physics measurement of Princeton Tokamaks, 1977-1987.

PubMed

Stencel, J R; Gilbert, J D; Couch, J G; Griesbach, O A; Fennimore, J J; Greco, J M

1989-06-01

The Princeton Plasma Physics Laboratory (PPPL) began fusion experiments in 1951. In the early years, the major health physics concerns were associated with x radiation produced by energetic electrons in the plasma. Within the past year, neutron and 3H production from 2H-2H (represented hereafter as D-D) reactions has increased significantly on the larger fusion devices. Tritium retention noted in graphite tiles underscores the significance of material selection in present and future 3H-fueled fusion devices. This paper reports on operational health physics radiation measurements made on various PPPL machines over the past 10 y.

BRAF Fusion Analysis in Pilocytic Astrocytomas: KIAA1549-BRAF 15-9 Fusions Are More Frequent in the Midline Than Within the Cerebellum

PubMed Central

Faulkner, Claire; Ellis, Hayley Patricia; Shaw, Abigail; Penman, Catherine; Palmer, Abigail; Wragg, Christopher; Greenslade, Mark; Haynes, Harry Russell; Williams, Hannah; Lowis, Stephen; White, Paul; Williams, Maggie; Capper, David; Kurian, Kathreena Mary

2015-01-01

Abstract Pilocytic astrocytomas (PAs) are increasingly tested for KIAA1549-BRAF fusions. We used reverse transcription polymerase chain reaction for the 3 most common KIAA1549-BRAF fusions, together with BRAF V600E and histone H3.3 K27M analyses to identify relationships of these molecular characteristics with clinical features in a cohort of 32 PA patients. In this group, the overall BRAF fusion detection rate was 24 (75%). Ten (42%) of the 24 had the 16-9 fusion, 8 (33%) had only the 15-9 fusion, and 1 (4%) of the patients had only the 16-11 fusion. In the PAs with only the 15-9 fusion, 1 PA was in the cerebellum and 7 were centered in the midline outside of the cerebellum, that is, in the hypothalamus (n = 4), optic pathways (n = 2), and brainstem (n = 1). Tumors within the cerebellum were negatively associated with fusion 15-9. Seven (22%) of the 32 patients had tumor-related deaths and 25 of the patients (78%) were alive between 2 and 14 years after initial biopsy. Age, sex, tumor location, 16-9 fusion, and 15-9 fusion were not associated with overall survival. Thus, in this small cohort, 15-9 KIAA1549-BRAF fusion was associated with midline PAs located outside of the cerebellum; these tumors, which are generally difficult to resect, are prone to recurrence. PMID:26222501

Investigation of the Possibility of Using Nuclear Magnetic Spin Alignment

NASA Technical Reports Server (NTRS)

Dent, William V., Jr.

1998-01-01

The goal of the program to investigate a "Gasdynamic fusion propulsion system for space exploration" is to develop a fusion propulsion system for a manned mission to the planet mars. A study using Deuterium and Tritium atoms are currently in progress. When these atoms under-go fusion, the resulting neutrons and alpha particles are emitted in random directions (isotropically). The probable direction of emission is equal for all directions, thus resulting in wasted energy, massive shielding and cooling requirements, and serious problems with the physics of achieving fusion. If the nuclear magnetic spin moments of the deuterium and tritium nuclei could be precisely aligned at the moment of fusion, the stream of emitted neutrons could be directed out the rear of the spacecraft for thrust and the alpha particles directed forward into an electromagnet ot produce electricity to continue operating the fusion engine. The following supporting topics are discussed: nuclear magnetic moments and spin precession in magnetic field, nuclear spin quantum mechanics, kinematics of nuclear reactions, and angular distribution of particles.

On the path to fusion energy

NASA Astrophysics Data System (ADS)

Tabak, M.

2016-10-01

There is a need to develop alternate energy sources in the coming century because fossil fuels will become depleted and their use may lead to global climate change. Inertial fusion can become such an energy source, but significant progress must be made before its promise is realized. The high-density approach to inertial fusion suggested by Nuckolls et al. leads reaction chambers compatible with civilian power production. Methods to achieve the good control of hydrodynamic stability and implosion symmetry required to achieve these high fuel densities will be discussed. Fast Ignition, a technique that achieves fusion ignition by igniting fusion fuel after it is assembled, will be described along with its gain curves. Fusion costs of energy for conventional hotspot ignition will be compared with those of Fast Ignition and their capital costs compared with advanced fission plants. Finally, techniques that may improve possible Fast Ignition gains by an order of magnitude and reduce driver scales by an order of magnitude below conventional ignition requirements are described.

Additive effects on the energy barrier for synaptic vesicle fusion cause supralinear effects on the vesicle fusion rate

PubMed Central

Schotten, Sebastiaan; Meijer, Marieke; Walter, Alexander Matthias; Huson, Vincent; Mamer, Lauren; Kalogreades, Lawrence; ter Veer, Mirelle; Ruiter, Marvin; Brose, Nils; Rosenmund, Christian

2015-01-01

The energy required to fuse synaptic vesicles with the plasma membrane (‘activation energy’) is considered a major determinant in synaptic efficacy. From reaction rate theory, we predict that a class of modulations exists, which utilize linear modulation of the energy barrier for fusion to achieve supralinear effects on the fusion rate. To test this prediction experimentally, we developed a method to assess the number of releasable vesicles, rate constants for vesicle priming, unpriming, and fusion, and the activation energy for fusion by fitting a vesicle state model to synaptic responses induced by hypertonic solutions. We show that complexinI/II deficiency or phorbol ester stimulation indeed affects responses to hypertonic solution in a supralinear manner. An additive vs multiplicative relationship between activation energy and fusion rate provides a novel explanation for previously observed non-linear effects of genetic/pharmacological perturbations on synaptic transmission and a novel interpretation of the cooperative nature of Ca2+-dependent release. DOI: http://dx.doi.org/10.7554/eLife.05531.001 PMID:25871846

Cluster-impact fusion, or beam-contaminant fusion? (abstract)a),b)

NASA Astrophysics Data System (ADS)

Lo, Daniel H.; Petrasso, Richard D.; Wenzel, Kevin W.

1992-10-01

Beuhler, Friedlander, and Friedman (BFF) reported anomalously huge D-D fusion rates while bombarding deuterated targets with (D2O)N+ clusters (N˜25-1000) accelerated to ≊325 keV [R. J. Beuhler et al., Phys. Rev. Lett. 63, 1292 (1989); R. J. Beuhler et al., J. Phys. Chem. 94, 7665 (1990)] [i.e., ≊0.3 keV lab energy for D in (D2O)100+]. However, from our analysis of BFF's fusion product spectra, we conclude that their D lab energy was ˜50 keV. Therefore, no gross anomalies exist. Also, from our analysis of the BFF beam-ranging experiments through 500 μg/cm2 of Au, we conclude that light-ion-beam contaminants (e.g., D+ of order 100 keV) have not been ruled out, and are the probable cause of their fusion reactions. This work was supported by LLNL Subcontract B116798, Department of Energy (DOE) Grant No. DE-FG02-91ER54109, DOE Magnetic Fusion Energy Technology Fellowship Program (D. H. Lo), and DOE Fusion Energy Postdoctoral Research Program (Kevin W. Wenzel).

Measuring spatial distributions of nuclear burn in ICF implosions at OMEGA and the NIF using proton emission imaging

NASA Astrophysics Data System (ADS)

Seguin, Fredrick; Rinderknecht, H. G.; Zylstra, A.; Sio, H.; Frenje, J.; Li, C. K.; Petrasso, R.; Rosenberg, M.; Marshall, F. J.; Sangster, T. C.; McKenty, P.; Craxton, S.; Rygg, J. R.; Le Pape, S.; Smalyuk, V.; Amendt, P. A.; Wilks, S. C.; MacKinnon, A.; Hoffman, N. M.

2015-11-01

Fusion reactions in ICF implosions of D3He-filled capsules produce 14.7-MeV D3He protons and 3-MeV DD protons. Spatial distributions of the D3He and DD reactions are studied with a penumbral imaging camera that utilizes a CR-39-based imaging detector to detect the protons. Up to three orthogonal cameras have been used simultaneously at OMEGA to study the 3-D structure of asymmetric implosions, and two orthogonal cameras have now been used to study an exploding-pusher implosion at the NIF. Recent data from OMEGA and from the NIF will be shown. This work was supported in part by NLUF, US DOE, and LLE.

Concept for a high performance MHD airbreathing-IEC fusion rocket

NASA Astrophysics Data System (ADS)

Froning, H. D.; Miley, G. H.; Nadler, J.; Shaban, Y.; Momota, H.; Burton, E.

2001-02-01

Previous studies have shown that Single-State-to-Orbit (SSTO) vehicle propellant can be reduced by Magnets-Hydro-Dynamic (MHD) processes that minimize airbreathing propulsion losses and propellant consumption during atmospheric flight, and additional reduction in SSTO propellant is enabled by Inertial Electrostatic Confinement (IEC) fusion, whose more energetic reactions reduce rocket propellant needs. MHD airbreathing propulsion during an SSTO vehicle's initial atmospheric flight phase and IEC fusion propulsion during its final exo-atmospheric flight phase is therefore being explored. Accomplished work is not yet sufficient for claiming such a vehicle's feasibility. But takeoff and propellant mass for an MHD airbreathing and IEC fusion vehicle could be as much as 25 and 40 percent less than one with ordinary airbreathing and IEC fusion; and as much as 50 and 70 percent less than SSTO takeoff and propellant mass with MHD airbreathing and chemical rocket propulsion. .

Determination of the order of substrate addition to MspI DNA methyltransferase using a novel mechanism-based inhibitor.

PubMed Central

Taylor, C; Ford, K; Connolly, B A; Hornby, D P

1993-01-01

The cloning and overexpression of the MspI DNA methyltransferase as a functional fusion with glutathione S-transferase is described. The fusion enzyme retains full biological activity and has been used to investigate the interaction of substrates and inhibitors with MspI DNA methyltransferase. The fusion enzyme has been purified to homogeneity in a single step on GSH-agarose and is free from contaminating exonuclease activity. The enzyme can be photolabelled with S-adenosyl-L-methionine and the level of incorporation of label is enhanced by the presence of a nonspecific DNA duplex. In the presence of a cognate oligodeoxynucleotide, no photolabelling was observed since methyl transfer occurs instead. The inclusion of a mechanism-based inhibitor of C-5 deoxycytidine DNA methylation (an oligodeoxynucleotide containing the base 2-pyrimidinone-1-beta-D-2'-deoxyribofuranoside in the position of the deoxycytidine to which methyl addition occurs), which is thought to form a covalent interaction with the reactive cysteine of such enzymes, led to an enhancement of S-adenosyl-L-methionine photolabelling which suggests that, in contrast with results obtained with EcoRII DNA methyltransferase [Som and Friedman (1991) J. Biol. Chem. 266, 2937-2945], methylcysteine is not the photolabelled product. The implications of the results obtained with this mechanism-based inhibitor are discussed with respect to other C-5-specific DNA methyltransferases. Gel-retardation assays in the presence of cognate oligodeoxynucleotides that contain the reactive pyrimidinone base in place of the deoxycytidine target base are described. These demonstrate that most probably a stable covalent bond is formed between the methyltransferase and this oligodeoxynucleotide. However, the alternative of extremely tight non-covalent binding cannot be rigorously excluded. Furthermore, the results from these experiments indicate that the reaction mechanism proceeds in a manner similar to that of HhaI DNA methyltransferase with sequence-specific DNA binding being followed by addition of S-adenosyl-L-methionine and concomitant isomerization of the ternary complex leading to methyl transfer. S-Adenosyl-L-homocysteine appears to inhibit the reaction pathway as a result of either competition with the methyl donor and potentiation of a high-affinity interaction between the enzyme and DNA in an abortive ternary complex or through an allosteric interaction. Images Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Figure 14 PMID:8484730

Effects of magnetization on fusion product trapping and secondary neutron spectraa)

NASA Astrophysics Data System (ADS)

Knapp, P. F.; Schmit, P. F.; Hansen, S. B.; Gomez, M. R.; Hahn, K. D.; Sinars, D. B.; Peterson, K. J.; Slutz, S. A.; Sefkow, A. B.; Awe, T. J.; Harding, E.; Jennings, C. A.; Desjarlais, M. P.; Chandler, G. A.; Cooper, G. W.; Cuneo, M. E.; Geissel, M.; Harvey-Thompson, A. J.; Porter, J. L.; Rochau, G. A.; Rovang, D. C.; Ruiz, C. L.; Savage, M. E.; Smith, I. C.; Stygar, W. A.; Herrmann, M. C.

2015-05-01

By magnetizing the fusion fuel in inertial confinement fusion (ICF) systems, the required stagnation pressure and density can be relaxed dramatically. This happens because the magnetic field insulates the hot fuel from the cold pusher and traps the charged fusion burn products. This trapping allows the burn products to deposit their energy in the fuel, facilitating plasma self-heating. Here, we report on a comprehensive theory of this trapping in a cylindrical DD plasma magnetized with a purely axial magnetic field. Using this theory, we are able to show that the secondary fusion reactions can be used to infer the magnetic field-radius product, BR, during fusion burn. This parameter, not ρR, is the primary confinement parameter in magnetized ICF. Using this method, we analyze data from recent Magnetized Liner Inertial Fusion experiments conducted on the Z machine at Sandia National Laboratories. We show that in these experiments BR ≈ 0.34(+0.14/-0.06) MG . cm, a ˜ 14× increase in BR from the initial value, and confirming that the DD-fusion tritons are magnetized at stagnation. This is the first experimental verification of charged burn product magnetization facilitated by compression of an initial seed magnetic flux.

Analysis of the synaptotagmin family during reconstituted membrane fusion. Uncovering a class of inhibitory isoforms.

PubMed

Bhalla, Akhil; Chicka, Michael C; Chapman, Edwin R

2008-08-01

Ca(2+)-triggered exocytosis in neurons and neuroendocrine cells is regulated by the Ca(2+)-binding protein synaptotagmin (syt) I. Sixteen additional isoforms of syt have been identified, but little is known concerning their biochemical or functional properties. Here, we assessed the abilities of fourteen syt isoforms to directly regulate SNARE (soluble N-ethylmaleimide-sensitive factor (NSF) attachment protein receptor)-catalyzed membrane fusion. One group of isoforms stimulated neuronal SNARE-mediated fusion in response to Ca(2+), while another set inhibited SNARE catalyzed fusion in both the absence and presence of Ca(2+). Biochemical analysis revealed a strong correlation between the ability of syt isoforms to bind 1,2-dioleoyl phosphatidylserine (PS) and t-SNAREs in a Ca(2+)-promoted manner with their abilities to enhance fusion, further establishing PS and SNAREs as critical effectors for syt action. The ability of syt I to efficiently stimulate fusion was specific for certain SNARE pairs, suggesting that syts might contribute to the specificity of intracellular membrane fusion reactions. Finally, a subset of inhibitory syts down-regulated the ability of syt I to activate fusion, demonstrating that syt isoforms can modulate the function of each other.

Fusion and quality analysis for remote sensing images using contourlet transform

NASA Astrophysics Data System (ADS)

Choi, Yoonsuk; Sharifahmadian, Ershad; Latifi, Shahram

2013-05-01

Recent developments in remote sensing technologies have provided various images with high spatial and spectral resolutions. However, multispectral images have low spatial resolution and panchromatic images have low spectral resolution. Therefore, image fusion techniques are necessary to improve the spatial resolution of spectral images by injecting spatial details of high-resolution panchromatic images. The objective of image fusion is to provide useful information by improving the spatial resolution and the spectral information of the original images. The fusion results can be utilized in various applications, such as military, medical imaging, and remote sensing. This paper addresses two issues in image fusion: i) image fusion method and ii) quality analysis of fusion results. First, a new contourlet-based image fusion method is presented, which is an improvement over the wavelet-based fusion. This fusion method is then applied to a case study to demonstrate its fusion performance. Fusion framework and scheme used in the study are discussed in detail. Second, quality analysis for the fusion results is discussed. We employed various quality metrics in order to analyze the fusion results both spatially and spectrally. Our results indicate that the proposed contourlet-based fusion method performs better than the conventional wavelet-based fusion methods.

[Detection of ALK, ROS1 and RET fusion genes in non-small cell lung cancer patients and its clinicopathologic correlation].

PubMed

Zhong, Shan; Zhang, Haiping; Bai, Dongyu; Gao, Dehong; Zheng, Jie; Ding, Yi

2015-09-01

To study the prevalence of ALK, ROS1 and RET fusion genes in non-small cell lung cancer (NSCLC), and its correlation with clinicopathologic features. Formalin-fixed and paraffin-embedded tissue sections from samples of 302 patients with NSCLC were screened for ALK, ROS1, RET fusions by real-time polymerase chain reaction (PCR). All of the cases were validated by Sanger DNA sequencing. The relationship between ALK, ROS1, RET fusion genes and clinicopathologic features were analyzed. In the cohort of 302 NSCLC samples, 3.97% (12/302) were found to contain ALK fusion genes, including 3 cases with E13; A20 gene fusion, 3 cases with E6; A20 gene fusion and 3 cases with E20; A20 gene fusion. There was no statistically significant difference in patient's gender, age, smoking history and histologic type. Moreover, in the 302 NSCLC samples studied, 3.97% (12/302) were found to contain ROS1 fusion genes, with CD74-ROS1 fusion identified in 9 cases. There was no statistically significant difference in patients' gender, age, smoking history and histologic type. One non-smoking elderly female patient with pulmonary adenocarcinoma had RET gene fusion. None of the cases studied had concurrent ALK, ROS1 and RET mutations. The ALK, ROS1 and RET fusion gene mutation rates in NSCLC are low, they represent some specific molecular subtypes of NSCLC. Genetic testing has significant meaning to guide clinical targeted therapy.

C-terminal tyrosine residues modulate the fusion activity of the Hendra virus fusion protein

PubMed Central

Popa, Andreea; Pager, Cara Teresia; Dutch, Rebecca Ellis

2011-01-01

The paramyxovirus family includes important human pathogens such as measles, mumps, respiratory syncytial virus and the recently emerged, highly pathogenic Hendra and Nipah viruses. The viral fusion (F) protein plays critical roles in infection, promoting both the viral-cell membrane fusion events needed for viral entry as well as cell-cell fusion events leading to syncytia formation. We describe the surprising finding that addition of the short epitope HA tag to the cytoplasmic tail (CT) of the Hendra virus F protein leads to a significant increase in cell-cell membrane fusion. This increase was not due to alterations in surface expression, cleavage state, or association with lipid microdomains. Addition of a Myc tag of similar length did not alter Hendra F fusion activity, indicating that the observed stimulation was not solely a result of lengthening the CT. Three tyrosine residues within the HA tag were critical for the increase in fusion, suggesting C-terminal tyrosines may modulate Hendra fusion activity. The effects of HA tag addition varied with other fusion proteins, as parainfluenza virus 5 F-HA showed decreased surface expression and no stimulation in fusion. These results indicate that additions to the C-terminal end of the F protein CT can modulate protein function in a sequence specific manner, reinforcing the need for careful analysis of epitope tagged glycoproteins. In addition, our results implicate C-terminal tyrosine residues in modulation of the membrane fusion reaction promoted by these viral glycoproteins. PMID:21175223

Enhancement of fusion at near-barrier energies for neutron-rich light nuclei: 19O +12 C

NASA Astrophysics Data System (ADS)

Singh, Varinderjit; Vadas, J.; Steinbach, T. K.; Wiggins, B. B.; Hudan, S.; Desouza, R. T.; Baby, L. T.; Kuvin, S. A.; Tripathi, Vandana; Wiedenhover, I.; Umar, A. S.

2017-01-01

Measuring the fusion excitation function for an isotopic chain of projectile nuclei provides a sensitive test of a microscopic description of fusion. To investigate the theoretically predicted fusion enhancement for neutron-rich light nuclei, an experiment was performed to measure the fusion excitation functions for 19 O +12 C and 18 O +12 C . Using the 18O(d,p) reaction and the RESOLUT mass spectrometer at Florida State University, a beam of 19O was produced with an intensity of 2-4 x 103 p/s. This beam bombarded a 100 μg/cm2 carbon target. Using an approach optimized for the measurement of fusion with a low-intensity beam, evaporation residues (ERs) resulting from the de-excitation of the fusion product were measured. The ERs were identified by measuring their energy and time-of-flight. At near-barrier energies, an enhancement of fusion by a factor of three has been observed for 19 O +12 C in comparison to 18 O +12 C . Comparison of the experimental results with the predictions of a density constrained time-dependent Hartree-Fock (DC-TDHF) model provide evidence for the importance of pairing in the fusion process. Supported by the US DOE under Grant No. DEFG02-88ER-40404.

Adult-onset renal cell carcinoma associated with Xp11.2 translocations/TFE3 gene fusion with smooth muscle stroma and abnormal vessels.

PubMed

Kuroda, Naoto; Tamura, Masato; Tanaka, Yukichi; Hes, Ondrej; Michal, Michal; Inoue, Kaori; Ohara, Masahiko; Mizuno, Keiko; Lee, Gang-Hong

2009-07-01

Renal cell carcinoma (RCC) associated with Xp11.2 translocation/TFE3 gene fusion has been recently identified. Herein is presented a case of RCC with Xp11.2 translocations/TFE3 gene fusions with unusual histological findings. A 68-year-old Japanese woman was incidentally found to have a renal mass on CT. Histological examination showed clear cell neoplasm with alveolar and papillary growth patterns. The nuclear atypia corresponded to Fuhrman grade 3. Additionally, smooth muscle stroma was observed and abnormal vessels showing a heterogeniety in thickness were also identified. On immunohistochemistry, neoplastic cells were diffusely positive for transcription factor E3 (TFE3) and Melan A, and focally positive for CD10 and RCC marker. The smooth muscle stroma was positive for alpha-smooth muscle actin and h-caldesmon, but reverse transcription-polymerase chain reaction of the tumor using frozen material could not detect any previously reported chimeric transcripts including ASPL-TFE3, PRCC-TFE3, CLTC-TFE3, PSF-TFE3 or NoNo-TFE3. G-band karyotype was unsuccessful. Pathologists should pay attention to the afore-described unusual stromal reaction of adult-onset RCC associated with Xp11.2 translocations/TFE3 gene fusions.

Nuclear phenomena in low-energy nuclear reaction research.

PubMed

Krivit, Steven B

2013-09-01

This is a comment on Storms E (2010) Status of Cold Fusion, Naturwissenschaften 97:861-881. This comment provides the following remarks to other nuclear phenomena observed in low-energy nuclear reactions aside from helium-4 make significant contributions to the overall energy balance; and normal hydrogen, not just heavy hydrogen, produces excess heat.

Real causes of apparent abnormal results in heavy ion reactions

NASA Astrophysics Data System (ADS)

Mandaglio, G.; Nasirov, A. K.; Anastasi, A.; Curciarello, F.; De Leo, V.; Fazio, G.; Giardina, G.

2015-06-01

We study the effect of the static characteristics of nuclei and dynamics of the nucleus-nucleus interaction in the capture stage of reaction, in the competition between quasifission and complete fusion processes, as well as the angular momentum dependence of the competition between fission and evaporation processes along the de-excitation cascade of the compound nucleus. The results calculated for the mass-asymmetric and less mass-asymmetric reactions in the entrance channel are analyzed in order to investigate the role of the dynamical effects on the yields of the evaporation residue nuclei. We also discuss about uncertainties at the extraction of such relevant physical quantities as Γn/Γtot ratio or also excitation functions from the experimental results due to the not always realistic assumptions in the treatment and analysis of the detected events. This procedure can lead to large ambiguity when the complete fusion process is strongly hindered or when the fast fission contribution is large. We emphasize that a refined multiparameter model of the reaction dynamics as well as a more detailed and checked data analysis are strongly needed in heavy-ion collisions.

Measurement of the fusion probability P{sub CN} for the reaction of {sup 50}Ti with {sup 208}Pb

DOE Office of Scientific and Technical Information (OSTI.GOV)

Naik, R. S.; Loveland, W.; Sprunger, P. H.

2007-11-15

The capture cross sections and fission fragment angular distributions were measured for the reaction of {sup 50}Ti with {sup 208}Pb at center of mass projectile energies (E{sub c.m.}) of 183.7, 186.2, 190.2, 194.2, and 202.3 MeV (E*=14.2, 16.6, 20.6, 24.7, and 32.7 MeV). From fitting the backward angle fragment angular distributions, the cross sections for quasifission and fusion-fission and P{sub CN}, the probability that the colliding nuclei go from the contact configuration to inside the fission saddle point, were deduced. These quantities, along with the known values of the evaporation residue production cross sections for this reaction, were used tomore » deduce values of the survival probabilities, W{sub sur}, for this reaction as a function of excitation energy. The deduced values of P{sub CN} and W{sub sur} and their dependence on excitation energy differ from some current theoretical predictions of these quantities.« less

Barrier modification in sub-barrier fusion reaction 64Ni+100Mo using Wong formula with Skyrme forces in semiclassical formalism

NASA Astrophysics Data System (ADS)

Kumar, Raj; Gupta, Raj K.

2011-09-01

We obtain the nuclear proximity potential by using semiclassical extended Thomas Fermi (ETF) approach in Skyrme energy density formalism (SEDF), and use it in the extended l-summed Wong formula under frozen density approximation. This method has the advantage of allowing the use of different Skyrme forces, giving different barriers. Thus, for a given reaction, we could choose a Skyrme force with proper barrier characteristics, not-requiring extra "barrier lowering" or "barrier narrowing" for a best fit to data. For the 64Ni+100Mo reaction, the l-summed Wong formula, with effects of deformations and orientations of nuclei included, fits the fusion-evaporation cross section data exactly for the force GSkI, requiring additional barrier modifications for forces SIII and SV. However, the same for other similar reactions, like 58,64Ni+58,64Ni, fit the data best for SIII force. Hence, the barrier modification effects in l-summed Wong expression depend on the choice of Skyrme force in semiclassical ETF method.

Resonant Interaction, Approximate Symmetry, and Electromagnetic Interaction (EMI) in Low Energy Nuclear Reactions (LENR)

NASA Astrophysics Data System (ADS)

Chubb, Scott

2007-03-01

Only recently (talk by P.A. Mosier-Boss et al, in this session) has it become possible to trigger high energy particle emission and Excess Heat, on demand, in LENR involving PdD. Also, most nuclear physicists are bothered by the fact that the dominant reaction appears to be related to the least common deuteron(d) fusion reaction,d+d ->α+γ. A clear consensus about the underlying effect has also been illusive. One reason for this involves confusion about the approximate (SU2) symmetry: The fact that all d-d fusion reactions conserve isospin has been widely assumed to mean the dynamics is driven by the strong force interaction (SFI), NOT EMI. Thus, most nuclear physicists assume: 1. EMI is static; 2. Dominant reactions have smallest changes in incident kinetic energy (T); and (because of 2), d+d ->α+γ is suppressed. But this assumes a stronger form of SU2 symmetry than is present; d+d ->α+γ reactions are suppressed not because of large changes in T but because the interaction potential involves EMI, is dynamic (not static), the SFI is static, and because the two incident deuterons must have approximate Bose Exchange symmetry and vanishing spin. A generalization of this idea involves a resonant form of reaction, similar to the de-excitation of an atom. These and related (broken gauge) symmetry EMI effects on LENR are discussed.

Polarized Nuclei in a Simple Mirror Fusion Reactor

NASA Technical Reports Server (NTRS)

Noever, David A.

1995-01-01

The possibility of enhancing the ratio of output to input power Q in a simple mirror machine by polarizing Deuterium-Tritium (D- T) nuclei is evaluated. Taking the Livermore mirror reference design mirror ratio of 6.54, the expected sin(sup 2) upsilon angular distribution of fusion decay products reduces immediate losses of alpha particles to the loss cone by 7.6% and alpha-ion scattering losses by approx. 50%. Based on these findings, alpha- particle confinement times for a polarized plasma should therefore be 1.11 times greater than for isotropic nuclei. Coupling this enhanced alpha-particle heating with the expected greater than 50% D- T reaction cross section, a corresponding power ratio for polarized nuclei, Q(sub polarized), is found to be 1.63 times greater than the classical unpolarized value Q(sub classical). The effects of this increase in Q are assessed for the simple mirror.

Latest results from LUNA

NASA Astrophysics Data System (ADS)

Depalo, Rosanna; LUNA Collaboration

2018-01-01

A precise knowledge of the cross section of nuclear fusion reactions is a crucial ingredient in understanding stellar evolution and nucleosynthesis. At stellar temperatures, fusion cross sections are extremely small and difficult to measure. Measuring nuclear cross sections at astrophysical energies is a challenge that triggered a huge amount of experimental work. A breakthrough in this direction was the first operation of an underground accelerator at the Laboratory for Underground Nuclear Astrophysics (LUNA) in Gran Sasso, Italy. The 1400 meters of rocks above the laboratory act as a natural shield against cosmic radiation, suppressing the background by orders of magnitude. The latest results achieved at LUNA are discussed, with special emphasis on the 22Ne(p,γ)23Na reaction. Future perspectives of the LUNA experiment are also illustrated.

Evidence for Stratification of Deuterium-Tritium Fuel in Inertial Confinement Fusion Implosions

NASA Astrophysics Data System (ADS)

Casey, D. T.; Frenje, J. A.; Gatu Johnson, M.; Manuel, M. J.-E.; Rinderknecht, H. G.; Sinenian, N.; Séguin, F. H.; Li, C. K.; Petrasso, R. D.; Radha, P. B.; Delettrez, J. A.; Glebov, V. Yu; Meyerhofer, D. D.; Sangster, T. C.; McNabb, D. P.; Amendt, P. A.; Boyd, R. N.; Rygg, J. R.; Herrmann, H. W.; Kim, Y. H.; Bacher, A. D.

2012-02-01

Measurements of the D(d,p)T (dd) and T(t,2n)He4 (tt) reaction yields have been compared with those of the D(t,n)He4 (dt) reaction yield, using deuterium-tritium gas-filled inertial confinement fusion capsule implosions. In these experiments, carried out on the OMEGA laser, absolute spectral measurements of dd protons and tt neutrons were obtained. From these measurements, it was concluded that the dd yield is anomalously low and the tt yield is anomalously high relative to the dt yield, an observation that we conjecture to be caused by a stratification of the fuel in the implosion core. This effect may be present in ignition experiments planned on the National Ignition Facility.

Note: Coincidence measurements of 3He and neutrons from a compact D-D neutron generator.

PubMed

Ji, Q; Lin, C-J; Tindall, C; Garcia-Sciveres, M; Schenkel, T; Ludewigt, B A

2017-05-01

Tagging of neutrons (2.45 MeV) with their associated 3 He particles from deuterium-deuterium (D-D) fusion reactions has been demonstrated in a compact neutron generator setup enabled by a high brightness, microwave-driven ion source with a high fraction of deuterons. Energy spectra with well separated peaks of the D-D fusion reaction products, 3 He, tritons, and protons, were measured with a silicon PIN diode. The neutrons were detected using a liquid scintillator detector with pulse shape discrimination. By correlating the 3 He detection events with the neutron detection in time, we demonstrated the tagging of emitted neutrons with 3 He particles detected with a Si PIN diode detector mounted inside the neutron generator vacuum vessel.

Ion-ion charge exchange processes. Final technical report, June 1, 1977-May 31, 1978

DOE Office of Scientific and Technical Information (OSTI.GOV)

Poe, R.T.; Choi, B.H.

Under the auspices of ERDA, we have undertaken a vigorous study of ion-ion charge exchange process pertinent to the storage-ring configurations in the heavy-ion fusion program. One particular reaction, singly charged helium charge exchange, was investigated in detail. General trend of the singly charged heavy-ion charge exchange reaction can be inferred from the present study. Some of our results were presented at Proceedings of the Heavy-Ion Fusion Workshop, Argonne National Laboratory (September 1978) as a paper entitled Charge Exchange Between Singly Ionized Helium Ions, by B.H. Choi, R.T. Poe and K.T. Tang. Here, we briefly describe our method and reportmore » the results.« less

Evidence for stratification of deuterium-tritium fuel in inertial confinement fusion implosions.

PubMed

Casey, D T; Frenje, J A; Johnson, M Gatu; Manuel, M J-E; Rinderknecht, H G; Sinenian, N; Séguin, F H; Li, C K; Petrasso, R D; Radha, P B; Delettrez, J A; Glebov, V Yu; Meyerhofer, D D; Sangster, T C; McNabb, D P; Amendt, P A; Boyd, R N; Rygg, J R; Herrmann, H W; Kim, Y H; Bacher, A D

2012-02-17

Measurements of the D(d,p)T (dd) and T(t,2n)(4)He (tt) reaction yields have been compared with those of the D(t,n)(4)He (dt) reaction yield, using deuterium-tritium gas-filled inertial confinement fusion capsule implosions. In these experiments, carried out on the OMEGA laser, absolute spectral measurements of dd protons and tt neutrons were obtained. From these measurements, it was concluded that the dd yield is anomalously low and the tt yield is anomalously high relative to the dt yield, an observation that we conjecture to be caused by a stratification of the fuel in the implosion core. This effect may be present in ignition experiments planned on the National Ignition Facility.

A novel framework of tissue membrane systems for image fusion.

PubMed

Zhang, Zulin; Yi, Xinzhong; Peng, Hong

2014-01-01

This paper proposes a tissue membrane system-based framework to deal with the optimal image fusion problem. A spatial domain fusion algorithm is given, and a tissue membrane system of multiple cells is used as its computing framework. Based on the multicellular structure and inherent communication mechanism of the tissue membrane system, an improved velocity-position model is developed. The performance of the fusion framework is studied with comparison of several traditional fusion methods as well as genetic algorithm (GA)-based and differential evolution (DE)-based spatial domain fusion methods. Experimental results show that the proposed fusion framework is superior or comparable to the other methods and can be efficiently used for image fusion.

A New Approach to Image Fusion Based on Cokriging

NASA Technical Reports Server (NTRS)

Memarsadeghi, Nargess; LeMoigne, Jacqueline; Mount, David M.; Morisette, Jeffrey T.

2005-01-01

We consider the image fusion problem involving remotely sensed data. We introduce cokriging as a method to perform fusion. We investigate the advantages of fusing Hyperion with ALI. The evaluation is performed by comparing the classification of the fused data with that of input images and by calculating well-chosen quantitative fusion quality metrics. We consider the Invasive Species Forecasting System (ISFS) project as our fusion application. The fusion of ALI with Hyperion data is studies using PCA and wavelet-based fusion. We then propose utilizing a geostatistical based interpolation method called cokriging as a new approach for image fusion.

Tryptophan tags and de novo designed complementary affinity ligands for the expression and purification of recombinant proteins.

PubMed

Pina, Ana Sofia; Carvalho, Sara; Dias, Ana Margarida G C; Guilherme, Márcia; Pereira, Alice S; Caraça, Luciana T; Coroadinha, Ana Sofia; Lowe, Christopher R; Roque, A Cecília A

2016-11-11

A common strategy for the production and purification of recombinant proteins is to fuse a tag to the protein terminal residues and employ a "tag-specific" ligand for fusion protein capture and purification. In this work, we explored the effect of two tryptophan-based tags, NWNWNW and WFWFWF, on the expression and purification of Green Fluorescence Protein (GFP) used as a model fusion protein. The titers obtained with the expression of these fusion proteins in soluble form were 0.11mgml -1 and 0.48mgml -1 for WFWFWF and NWNWNW, respectively. A combinatorial library comprising 64 ligands based on the Ugi reaction was prepared and screened for binding GFP-tagged and non-tagged proteins. Complementary ligands A2C2 and A3C1 were selected for the effective capture of NWNWNW and WFWFWF tagged proteins, respectively, in soluble forms. These affinity pairs displayed 10 6 M -1 affinity constants and Qmax values of 19.11±2.60ugg -1 and 79.39ugg -1 for the systems WFWFWF AND NWNWNW, respectively. GFP fused to the WFWFWF affinity tag was also produced as inclusion bodies, and a refolding-on column strategy was explored using the ligand A4C8, selected from the combinatorial library of ligands but in presence of denaturant agents. Copyright © 2016 Elsevier B.V. All rights reserved.

Expression and Activation of Horseradish Peroxidase-Protein A/G Fusion Protein in Silkworm Larvae for Diagnostic Purposes.

PubMed

Xxxx, Patmawati; Minamihata, Kosuke; Tatsuke, Tsuneyuki; Lee, Jae Man; Kusakabe, Takahiro; Kamiya, Noriho

2018-06-01

Recombinant protein production can create artificial proteins with desired functions by introducing genetic modifications to the target proteins. Horseradish peroxidase (HRP) has been used extensively as a reporter enzyme in biotechnological applications; however, recombinant production of HRP has not been very successful, hampering the utilization of HRP with genetic modifications. A fusion protein comprising an antibody binding protein and HRP will be an ideal bio-probe for high-quality HRP-based diagnostic systems. A HRP-protein A/G fusion protein (HRP-pAG) is designed and its production in silkworm (Bombyx mori) is evaluated for the first time. HRP-pAG is expressed in a soluble apo form, and is activated successfully by incubating with hemin. The activated HRP-pAG is used directly for ELISA experiments and retains its activity over 20 days at 4 °C. Moreover, HRP-pAG is modified with biotin by the microbial transglutaminase (MTG) reaction. The biotinylated HRP-pAG is conjugated with streptavidin to form a HRP-pAG multimer and the multimeric HRP-pAG produced higher signals in the ELISA system than monomeric HRP-pAG. The successful production of recombinant HRP in silkworm will contribute to creating novel HRP-based bioconjugates as well as further functionalization of HRP by applying enzymatic post-translational modifications. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Low-Energy Nuclear Reactions Resulting as Picometer Interactions with Similarity to K-Shell Electron Capture

NASA Astrophysics Data System (ADS)

Hora, H.; Miley, G. H.; Li, X. Z.; Kelly, J. C.; Osman, F.

2006-02-01

Since the appeal by Brian Josephson at the meeting of the Nobel Laureates July 2004, it seems to be indicated to summarize the following serious, reproducible and confirmed observations on reactions of protons or deuterons incorporated in host metals such as palladium. Some reflections to Rutherford's discovery of nuclear physics, the Cockroft-Oliphant discovery of anomalous low-energy fusion reactions and the chemist Hahn's discovery of fission had to be included. Using gaseous atmosphere or discharges between palladium targets, rather significant results were seen e.g. from the "life after death" heat production of such high values per host atom that only nuclear reactions can be involved. This supports the earlier evaluation of neutron generation in fully reversible experiments with gas discharges hinting that a reasonable screening effect - preferably in the swimming electron layer - may lead to reactions at nuclear distances d of picometers with reaction probability times U of about megaseconds similar to the K-shell capture radioactivity. Further electrolytic experiments led to low-energy nuclear reactions (LENR) where the involvement of pollution could be excluded from the appearance of very seldom rare earth elements. A basically new theory for DD cross-sections is used to confirm the picometer-megasecond reactions of cold fusion. Other theoretical aspects are given from measured heavy element distributions similar to the standard abundance distribution, SAD, in the Universe with consequences on endothermic heavy nuclei generation, magic numbers and to quark-gluon plasmas.

The Trojan Horse Method in Nuclear Astrophysics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Spitaleri, C.

2010-11-24

The Trojan Horse Method allows for the measurements of cross section in nuclear reaction between charged particles at astrophysical energies. The basic features of the method are discussed in the non resonant reactions case. A review of applications aimed to extract the bare nucleus astrophysical S{sub b}(E) factor for two body processes are presented. The information on electron screening potential U{sub e} were obtained from comparison with direct experiments of fusion reactions.

Construction of membrane-anchoring fusion protein of Thermococcus kodakaraensis glycerol kinase and its application to repetitive batchwise reactions.

PubMed

Restiawaty, Elvi; Honda, Kohsuke; Okano, Kenji; Hirota, Ryuichi; Omasa, Takeshi; Kuroda, Akio; Ohtake, Hisao

2012-04-01

We previously demonstrated the stoichiometric conversion of glycerol to glycerol-3-phosphate (G3P) using Escherichia coli recombinants producing the ATP-dependent glycerol kinase of the hyperthermophile Thermococcus kodakaraensis (TkGK) and the polyphosphate kinase of Thermus thermophilus HB27 (TtPPK). TtPPK was associated with the membrane fraction of E. coli recombinants, whereas TkGK was released from the cells during the reaction at 70°C. In this study, TkGK was fused with either TtPPK or an E. coli membrane-intrinsic protein, YedZ, to minimize the heat-induced leakage of TkGK. When the E. coli recombinants having these fusion proteins were incubated at 70°C for 2h, more than 80% of TkGK activity was retained in the heated E. coli cells. However, the yields of G3P production by E. coli having the fusion proteins of TtPPK and TkGK were only less than 35%. Polyphosphate is a strong chelator for metal ions and has an inhibitory effect on TkGK which requires magnesium. Insufficient space between TtPPK and TkGK might enhance the inhibitory effect of polyphosphate on TkGK activity of the fusion protein. The mixture of E. coli cells having TtPPK and those having TkGK fused with YedZ converted 80% of glycerol into G3P. These recombinant cells could be easily recovered from the reaction mixture by centrifugation and repeatedly used without a significant loss of enzyme activities. Copyright © 2011 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

SU-E-T-656: Quantitative Analysis of Proton Boron Fusion Therapy (PBFT) in Various Conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yoon, D; Jung, J; Shin, H

2015-06-15

Purpose: Three alpha particles are concomitant of proton boron interaction, which can be used in radiotherapy applications. We performed simulation studies to determine the effectiveness of proton boron fusion therapy (PBFT) under various conditions. Methods: Boron uptake regions (BURs) of various widths and densities were implemented in Monte Carlo n-particle extended (MCNPX) simulation code. The effect of proton beam energy was considered for different BURs. Four simulation scenarios were designed to verify the effectiveness of integrated boost that was observed in the proton boron reaction. In these simulations, the effect of proton beam energy was determined for different physical conditions,more » such as size, location, and boron concentration. Results: Proton dose amplification was confirmed for all proton beam energies considered (< 96.62%). Based on the simulation results for different physical conditions, the threshold for the range in which proton dose amplification occurred was estimated as 0.3 cm. Effective proton boron reaction requires the boron concentration to be equal to or greater than 14.4 mg/g. Conclusion: We established the effects of the PBFT with various conditions by using Monte Carlo simulation. The results of our research can be used for providing a PBFT dose database.« less

Effect of deformations on the compactness of odd-Z superheavy nuclei formed in cold and hot fusion reactions

NASA Astrophysics Data System (ADS)

Kaur, Gurjit; Sandhu, Kirandeep; Sharma, Manoj K.

2018-03-01

Using the extended fragmentation theory, the compactness of hot and cold fusion reactions is analyzed for odd-Z nuclei ranging Z = 105- 117. The calculations for the present work are carried out at T = 0MeV and ℓ = 0 ħ, as the temperature and angular momentum effects remain silent while addressing the orientation degree of freedom (i.e. compact angle configuration). In the hot fusion, 48Ca (spherical) + actinide (prolate) reaction, the non-equatorial compact (nec) shape is obtained for Z = 113 nucleus. On the other hand, Z > 113 nuclei favor equatorial compact (ec) configuration. The distribution of barrier height (VB) illustrate that the ec-shape is obtained when the magnitude of quadrupole deformation of the nucleus is higher than the hexadecupole deformation. In other words, negligible or small -ve β4-deformations support ec configurations. On the other hand, large (+ve) magnitude of the β4-deformation suggests that the configuration appears for compact angle θc < 90 °, leading to nec structure. Similar deformation effects are observed for Bi-induced reactions, in which not belly-to-belly compact (nbbc) configurations are seen at θc = 42 °. In addition to the effect of β2 and β4-deformations, the exclusive role of octupole deformations (β3) is also analyzed. The β3-deformations do not follow the reflection symmetry as that of β2 and β4, leading to the possible occurrence of compact configuration within 0° to 180° angular range.

Fluorescent Labeling of COS-7 Expressing SNAP-tag Fusion Proteins for Live Cell Imaging

PubMed Central

Provost, Christopher R.; Sun, Luo

2010-01-01

SNAP-tag and CLIP-tag protein labeling systems enable the specific, covalent attachment of molecules, including fluorescent dyes, to a protein of interest in live cells. These systems offer a broad selection of fluorescent substrates optimized for a range of imaging instrumentation. Once cloned and expressed, the tagged protein can be used with a variety of substrates for numerous downstream applications without having to clone again. There are two steps to using this system: cloning and expression of the protein of interest as a SNAP-tag fusion, and labeling of the fusion with the SNAP-tag substrate of choice. The SNAP-tag is a small protein based on human O6-alkylguanine-DNA-alkyltransferase (hAGT), a DNA repair protein. SNAP-tag labels are dyes conjugated to guanine or chloropyrimidine leaving groups via a benzyl linker. In the labeling reaction, the substituted benzyl group of the substrate is covalently attached to the SNAP-tag. CLIP-tag is a modified version of SNAP-tag, engineered to react with benzylcytosine rather than benzylguanine derivatives. When used in conjunction with SNAP-tag, CLIP-tag enables the orthogonal and complementary labeling of two proteins simultaneously in the same cells. PMID:20485262

New Fusion Concept Using Coaxial Passing Through Each Other Self-focusing Colliding Beams (Invention)

NASA Astrophysics Data System (ADS)

Chikvashvili, Ioseb

2011-10-01

In proposed Concept it is offered to use two ion beams directed coaxially at the same direction but with different velocities (center-of-mass collision energy should be sufficient for fusion), to direct oppositely the relativistic electron beam for only partial compensation of positive space charge and for allowing the combined beam's pinch capability, to apply the longitudinal electric field for compensation of alignment of velocities of reacting particles and also for compensation of energy losses of electrons via Bremsstrahlung. On base of Concept different types of reactor designs can be realized: Linear and Cyclic designs. In the simplest embodiment the Cyclic Reactor (design) may include: betatron type device (circular store of externally injected particles - induction accelerator), pulse high-current relativistic electron injector, pulse high-current slower ion injector, pulse high-current faster ion injector and reaction products extractor. Using present day technologies and materials (or a reasonable extrapolation of those) it is possible to reach: for induction linear injectors (ions&electrons) - currents of thousands A, repeatability - up to 10Hz, the same for high-current betatrons (FFAG, Stellatron, etc.). And it is possible to build the fusion reactor using the proposed Method just today.

Detection of Echinoderm Microtubule Associated Protein Like 4-Anaplastic Lymphoma Kinase Fusion Genes in Non-small Cell Lung Cancer Clinical Samples by a Real-time Quantitative Reverse Transcription Polymerase Chain Reaction Method.

PubMed

Zhao, Jing; Zhao, Jin-Yin; Chen, Zhi-Xia; Zhong, Wei; Li, Long-Yun; Liu, Li-Cheng; Hu, Xiao-Xu; Chen, Wei-Jun; Wang, Meng-Zhao

2016-12-20

Objective To establish a real-time quantitative reverse transcription polymerase chain reaction assay (qRT-PCR) for the rapid, sensitive, and specific detection of echinoderm microtubule associated protein like 4-anaplastic lymphoma kinase (EML4-ALK) fusion genes in non-small cell lung cancer. Methods The specific primers for the four variants of EML4-ALK fusion genes (V1, V2, V3a, and V3b) and Taqman fluorescence probes for the detection of the target sequences were carefully designed by the Primer Premier 5.0 software. Then, using pseudovirus containing EML4-ALK fusion genes variants (V1, V2, V3a, and V3b) as the study objects, we further analyzed the lower limit, sensitivity, and specificity of this method. Finally, 50 clinical samples, including 3 ALK-fluorescence in situ hybridization (FISH) positive specimens, were collected and used to detect EML4-ALK fusion genes using this method. Results The lower limit of this method for the detection of EML4-ALK fusion genes was 10 copies/μl if no interference of background RNA existed. Regarding the method's sensitivity, the detection resolution was as high as 1% and 0.5% in the background of 500 and 5000 copies/μl wild-type ALK gene, respectively. Regarding the method's specificity, no non-specific amplification was found when it was used to detect EML4-ALK fusion genes in leukocyte and plasma RNA samples from healthy volunteers. Among the 50 clinical samples, 47 ALK-FISH negative samples were also negative. Among 3 ALK-FISH positive samples, 2 cases were detected positive using this method, but another was not detected because of the failure of RNA extraction. Conclusion The proposed qRT-PCR assay for the detection of EML4-ALK fusion genes is rapid, simple, sensitive, and specific, which is deserved to be validated and widely used in clinical settings.

Applications of Fusion Energy Sciences Research - Scientific Discoveries and New Technologies Beyond Fusion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wendt, Amy; Callis, Richard; Efthimion, Philip

Since the 1950s, scientists and engineers in the U.S. and around the world have worked hard to make an elusive goal to be achieved on Earth: harnessing the reaction that fuels the stars, namely fusion. Practical fusion would be a source of energy that is unlimited, safe, environmentally benign, available to all nations and not dependent on climate or the whims of the weather. Significant resources, most notably from the U.S. Department of Energy (DOE) Office of Fusion Energy Sciences (FES), have been devoted to pursuing that dream, and significant progress is being made in turning it into a reality.more » However, that is only part of the story. The process of creating a fusion-based energy supply on Earth has led to technological and scientific achievements of far-reaching impact that touch every aspect of our lives. Those largely unanticipated advances, spanning a wide variety of fields in science and technology, are the focus of this report. There are many synergies between research in plasma physics (the study of charged particles and fluids interacting with self-consistent electric and magnetic fields), high-energy physics, and condensed matter physics dating back many decades. For instance, the formulation of a mathematical theory of solitons, solitary waves which are seen in everything from plasmas to water waves to Bose-Einstein Condensates, has led to an equal span of applications, including the fields of optics, fluid mechanics and biophysics. Another example, the development of a precise criterion for transition to chaos in Hamiltonian systems, has offered insights into a range of phenomena including planetary orbits, two-person games and changes in the weather. Seven distinct areas of fusion energy sciences were identified and reviewed which have had a recent impact on fields of science, technology and engineering not directly associated with fusion energy: Basic plasma science; Low temperature plasmas; Space and astrophysical plasmas; High energy density laboratory plasmas and inertial fusion energy; Particle accelerator technology; Fusion nuclear science; and Magnetically confined plasmas. Individual sections within the report summarize applications associated with each of these areas. These sections were also informed by a survey that went out to the community, and the subcommittee wishes to thank those who responded, as well as to the national labs and universities that contributed photographs.« less

Fractal reaction kinetics.

PubMed

Kopelman, R

1988-09-23

Classical reaction kinetics has been found to be unsatisfactory when the reactants are spatially constrained on the microscopic level by either walls, phase boundaries, or force fields. Recently discovered theories of heterogeneous reaction kinetics have dramatic consequences, such as fractal orders for elementary reactions, self-ordering and self-unmixing of reactants, and rate coefficients with temporal "memories." The new theories were needed to explain the results of experiments and supercomputer simulations of reactions that were confined to low dimensions or fractal dimensions or both. Among the practical examples of "fractal-like kinetics" are chemical reactions in pores of membranes, excitation trapping in molecular aggregates, exciton fusion in composite materials, and charge recombination in colloids and clouds.

The Rab3A-22A Chimera Prevents Sperm Exocytosis by Stabilizing Open Fusion Pores*

PubMed Central

Quevedo, María F.; Lucchesi, Ornella; Bustos, Matías A.; Pocognoni, Cristian A.; De la Iglesia, Paola X.

2016-01-01

At the final stage of exocytotis, a fusion pore opens between the plasma and a secretory vesicle membranes; typically, when the pore dilates the vesicle releases its cargo. Sperm contain a large dense-core secretory granule (the acrosome) whose contents are secreted by regulated exocytosis at fertilization. Minutes after the arrival of the triggering signal, the acrosomal and plasma membranes dock at multiple sites and fusion pores open at the contact points. It is believed that immediately afterward, fusion pores dilate spontaneously. Rab3A is an essential component of human sperm exocytotic machinery. Yet, recombinant, persistently active Rab3A halts calcium-triggered secretion when introduced after docking into streptolysin O-permeabilized cells; so does a Rab3A-22A chimera. Here, we applied functional assays, electron and confocal microscopy to show that the secretion blockage is due to the stabilization of open fusion pores. Other novel findings are that sperm SNAREs engage in α-SNAP/NSF-sensitive complexes at a post-fusion stage. Complexes are disentangled by these chaperons to achieve vesiculation and acrosomal contents release. Thus, post-fusion regulation of the pores determines their expansion and the success of the acrosome reaction. PMID:27613869

CRTC1/MAML2 fusion transcript in central mucoepidermoid carcinoma of mandible--diagnostic and histogenetic implications.

PubMed

Bell, Diana; Holsinger, Christopher F; El-Naggar, Adel K

2010-12-01

Intraosseous salivary gland carcinomas are extremely rare, comprising only 2% to 3% of all mucoepidermoid carcinomas (MECs) reported. The t(11;19) translocation and its CRTC1/MAML1 fusion transcript have been identified in MEC at different sites and are believed to be associated with the development of a subset of these tumors. However, the status of the fusion transcript has not been reported in intraosseous MEC. Here, we report 3 examples of central MEC of the mandible, including a case with a history of primary retromolar MEC. Reverse transcriptase-polymerase chain reaction and DNA sequencing analyses of the microdissected components of these tumors were used for the detection and verification of the fusion transcript. We identified, for the first time, the t(11;19) fusion gene transcript in central MEC, including in the previous primary retromolar MEC. No fusion transcript was detected in the second primary noncentral MEC or in another central MEC. The results indicate that central MEC can manifest the fusion transcript. This finding may have diagnostic and histogenetic roles in the future analysis of this entity. Published by Elsevier Inc.

Association between EML4-ALK fusion gene and thymidylate synthase mRNA expression in non-small cell lung cancer tissues

PubMed Central

XU, CHUN-WEI; WANG, GANG; WANG, WU-LONG; GAO, WEN-BIN; HAN, CHUAN-JUN; GAO, JING-SHAN; ZHANG, LI-YING; LI, YANG; WANG, LIN; ZHANG, YU-PING; TIAN, YU-WANG; QI, DONG-DONG

2015-01-01

This study aimed to investigate the association of the mRNA expression of the echinoderm microtubule-associated protein-like 4 (EML4)-anaplastic lymphoma kinase (ALK) fusion gene with that of thymidylate synthase (TYMS) in non-small cell lung cancer (NSCLC) tissues. Quantitative polymerase chain reaction was used to detect the expression of EML4-ALK fusion gene and TYMS mRNA in 257 cases of NSCLC. The positive rate of EML4-ALK fusion gene was 4.28% in the NSCLC tissues (11/257), and was higher in nonsmokers than in smokers (P<0.05); TYMS mRNA expression was detected in 63.42% (163/257) of cases. An association of the EML4-ALK fusion gene with TYMS expression was detected; a low expression level of TYMS mRNA was observed more frequently when the EML4-ALK fusion gene was present than when it was not detected (P<0.05). In conclusion, patients positive for the EML4-ALK fusion gene in NSCLC tissues are likely to have a low expression level of TYMS, and may benefit from the first-line chemotherapy drug pemetrexed. PMID:26136951

Association between EML4-ALK fusion gene and thymidylate synthase mRNA expression in non-small cell lung cancer tissues.

PubMed

Xu, Chun-Wei; Wang, Gang; Wang, Wu-Long; Gao, Wen-Bin; Han, Chuan-Jun; Gao, Jing-Shan; Zhang, Li-Ying; Li, Yang; Wang, Lin; Zhang, Yu-Ping; Tian, Yu-Wang; Qi, Dong-Dong

2015-06-01

This study aimed to investigate the association of the mRNA expression of the echinoderm microtubule-associated protein-like 4 (EML4)-anaplastic lymphoma kinase (ALK) fusion gene with that of thymidylate synthase (TYMS) in non-small cell lung cancer (NSCLC) tissues. Quantitative polymerase chain reaction was used to detect the expression of EML4-ALK fusion gene and TYMS mRNA in 257 cases of NSCLC. The positive rate of EML4-ALK fusion gene was 4.28% in the NSCLC tissues (11/257), and was higher in nonsmokers than in smokers (P<0.05); TYMS mRNA expression was detected in 63.42% (163/257) of cases. An association of the EML4-ALK fusion gene with TYMS expression was detected; a low expression level of TYMS mRNA was observed more frequently when the EML4-ALK fusion gene was present than when it was not detected (P<0.05). In conclusion, patients positive for the EML4-ALK fusion gene in NSCLC tissues are likely to have a low expression level of TYMS, and may benefit from the first-line chemotherapy drug pemetrexed.

Examining the role of transfer coupling in sub-barrier fusion of Ti 46 , 50 + Sn 124

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liang, J. Felix; Allmond, J. M.; Gross, C. J.

2016-08-24

In this study, the presence of neutron transfer channels with positive Q values can enhance sub-barrier fusion cross sections. Recent measurements of the fusion excitation functions for 58Ni+ 132,124Sn found that the fusion enhancement due to the influence of neutron transfer is smaller than that in 40Ca + 132,124Sn although the Q values for multineutron transfer are comparable. The purpose of this study is to investigate the differences observed between the fusion of Sn + Ni and Sn + Ca. Methods: Fusion excitation functions for 46,50Ti + 124Sn have been measured at energies near the Coulomb barrier. As a result,more » a comparison of the barrier distributions for 46Ti+ 124Sn and 40Ca+ 124Sn shows that the 40Ca+ 124Sn system has a barrier strength resulting from the coupling to the very collective octupole state in 40Ca at an energy significantly lower than the uncoupled barrier. In conclusion, the large sub-barrier fusion enhancement in 40Ca induced reactions is attributed to both couplings to neutron transfer and inelastic excitation, with the octupole vibration of 40Ca playing a major role.« less

A. Sakharov and Fusion Research

NASA Astrophysics Data System (ADS)

Coppi, Bruno

2012-02-01

In the landmark paper by Tamm and Sakharov [1], a controlled nuclear fusion reactor based on an axisymmetric magnetic confinement configuration whose principles remain valid to this day, was proposed. In the light of present understanding of plasma physics the virtues (e.g. that of considering the D-D reaction) and the shortcomings of this paper are pointed out. In fact, relatively recent results of theoretical plasma physics (e.g. discovery of the so called second stability region) and advances in high field magnet technology have made it possible to identify the parameters of meaningful experiments capable of exploring D-D and D-^3He burn conditions. At the same time an experimental program (IGNIR) has been undertaken through a (funded) collaboration between Italy and Russia to investigate D-T plasmas close to ignition conditions based on an advanced high field toroidal confinement configuration. A. Sakharov envisioned a bolder approach to fusion research than that advocated by some of his contemporaries. The time taken to design and decide to fabricate the first experiment capable of reaching ignition conditions is due in part to the problem of gaining an adequate understanding the expected physics of fusion burning plasmas. However, most of the relevant financial effort has gone in the pursuit of slow and indirect enterprises complying with the ``playing it safe'' tendencies of large organizations or motivated by the purpose to develop technologies or maintain a high level of expertise in plasma physics to the expected benefit of other kinds of endeavors. The creativity demonstrated by A. Sakharov in dealing with civil rights and disarmament issues is needed, while maintaining our concerns for energy and the environment on a global scale, to orient the funding for fusion research toward a direct and well based scientific effort on concepts for which a variety of developments can be envisioned. These can span from uncovering new physics relevant, for instance, to high energy astrophysics to the feasibility of new neutron sources.[4pt] [1] A. Sakharov, Collected Scientific Works (Publ. Marcel Dekkes, Inc., New York, N.Y., 1982).

Immunological characteristics of outer membrane protein omp31 of goat Brucella and its monoclonal antibody.

PubMed

Zheng, W Y; Wang, Y; Zhang, Z C; Yan, F

2015-10-05

We examined the immunological characteristics of outer membrane protein omp31 of goat Brucella and its monoclonal antibody. Genomic DNA from the M5 strain of goat Brucella was amplified by polymerase chain reaction and cloned into the prokaryotic expression vector pGEX-4T-1. The expression and immunological characteristics of the fusion protein GST-omp31 were subjected to preliminary western blot detection with goat Brucella rabbit immune serum. The Brucella immunized BALB/c mouse serum was detected using purified protein. The high-potency mouse splenocytes and myeloma Sp2/0 cells were fused. Positive clones were screened by enzyme-linked immunosorbent assay to establish a hybridoma cell line. Mice were inoculated intraperitoneally with hybridoma cells to prepare ascites. The mAb was purified using the n-caprylic acid-ammonium sulfate method. The characteristics of mAb were examined using western blotting and enzyme-linked immunosorbent assay. A 680-base pair band was observed after polymerase chain reaction. Enzyme digestion identification and sequencing showed that the pGEX-4T-1-omp31 prokaryotic expression vector was successfully established; a target band of approximately 57 kDa with an apparent molecular weight consistent with the size of the target fusion protein. At 25°C, the expression of soluble expression increased significantly; the fusion protein GST-omp31 was detected by western blotting. Anti-omp31 protein mAb was obtained from 2 strains of Brucella. The antibody showed strong specificity and sensitivity and did not cross-react with Escherichia coli, Staphylococcus aureus, Bacillus subtilis, Mycobacterium tuberculosis, or Bacillus pyocyaneus. The pGEX-4T-1-omp31 prokaryotic expression vector was successfully established and showed good immunogenicity. The antibody also showed strong specificity and good sensitivity.

Influence of laser induced hot electrons on the threshold for shock ignition of fusion reactions

NASA Astrophysics Data System (ADS)

Colaïtis, A.; Ribeyre, X.; Le Bel, E.; Duchateau, G.; Nicolaï, Ph.; Tikhonchuk, V.

2016-07-01

The effects of Hot Electrons (HEs) generated by the nonlinear Laser-Plasma Interaction (LPI) on the dynamics of Shock Ignition Inertial Confinement Fusion targets are investigated. The coupling between the laser beam, plasma dynamics and hot electron generation and propagation is described with a radiative hydrodynamics code using an inline model based on Paraxial Complex Geometrical Optics [Colaïtis et al., Phys. Rev. E 92, 041101 (2015)]. Two targets are considered: the pure-DT HiPER target and a CH-DT design with baseline spike powers of the order of 200-300 TW. In both cases, accounting for the LPI-generated HEs leads to non-igniting targets when using the baseline spike powers. While HEs are found to increase the ignitor shock pressure, they also preheat the bulk of the imploding shell, notably causing its expansion and contamination of the hotspot with the dense shell material before the time of shock convergence. The associated increase in hotspot mass (i) increases the ignitor shock pressure required to ignite the fusion reactions and (ii) significantly increases the power losses through Bremsstrahlung X-ray radiation, thus rapidly cooling the hotspot. These effects are less prominent for the CH-DT target where the plastic ablator shields the lower energy LPI-HE spectrum. Simulations using higher laser spike powers of 500 TW suggest that the CH-DT capsule marginally ignites, with an ignition window width significantly smaller than without LPI-HEs, and with three quarters of the baseline target yield. The latter effect arises from the relation between the shock launching time and the shell areal density, which becomes relevant in presence of a LPI-HE preheating.

Prospects for Alpha Particle Heating in JET in the Hot Ion Regime

NASA Astrophysics Data System (ADS)

Cordey, J. G.; Keilhacker, M.; Watkins, M. L.

1987-01-01

The prospects for alpha particle heating in JET are discussed. A computational model is developed to represent adequately the neutron yield from JET plasmas heated by neutral beam injection. This neutral beam model, augmented by a simple plasma model, is then used to determine the neutron yields and fusion Q-values anticipated for different heating schemes in future operation of JET with tritium. The relative importance of beam-thermal and thermal-thermal reactions is pointed out and the dependence of the results on, for example, plasma density, temperature, energy confinement and purity is shown. Full 1½-D transport code calculations, based on models developed for ohmic, ICRF and NBI heated JET discharges, are used also to provide a power scan for JET operation in tritium in the low density, high ion temperature regime. The results are shown to be in good agreement with the estimates made using the simple plasma model and indicate that, based on present knowledge, a fusion Q-value in the plasma centre above unity should be achieved in JET.

[Molecular cloning and expression of the severe acute respiratory syndrome-associated coronavirus nucleocapsid protein and its clinical application].

PubMed

Lu, Jian; Zhou, Bai-ping; Zhou, Yu-sen; Jiang, Xiao-ling; Wen, Li-xia; Le, Xiao-hua; Li, Bing; Xu, Liu-mei; Li, Li-xiong

2005-03-01

To clone and express nucleocapsid (N) protein of the severe acute respiratory syndrome (SARS)-associated coronavirus, and to evaluate its antigenicity and application value in the development of serological diagnostic test for SARS. SARS-associated coronavirus N protein gene was amplified from its genomic RNA by reverse transcript nested polymerase chain reaction (RT-nested-PCR) and cloned into pBAD/Thio-TOPO prokaryotic expression vector. The recombinant N fusion protein was expressed and purified, and its antigenicity and specificity was analyzed by Western Blot, to establish the recombinant N protein-based ELISA for detection of IgG antibodies to SARS-associated coronavirus, and SARS-associated coronavirus lysates-based ELISA was compared parallelly. The recombinant expression vector produced high level of the N fusion protein after induction, and that protein was purified successfully by affinity chromatography and displayed higher antigenicity and specificity as compared with whole virus lysates. The recombinant SARS-associated coronavirus N protein possessed better antigenicity and specificity and could be employed to establish a new, sensitive, and specific ELISA for SARS diagnosis.

An SH2 domain-based tyrosine kinase assay using biotin ligase modified with a terbium(III) complex.

PubMed

Sueda, Shinji; Shinboku, Yuki; Kusaba, Takeshi

2013-01-01

Src homology 2 (SH2) domains are modules of approximately 100 amino acids and are known to bind phosphotyrosine-containing sequences with high affinity and specificity. In the present work, we developed an SH2 domain-based assay for Src tyrosine kinase using a unique biotinylation reaction from archaeon Sulfolobus tokodaii. S. tokodaii biotinylation has a unique property that biotin protein ligase (BPL) forms a stable complex with its biotinylated substrate protein (BCCP). Here, an SH2 domain from lymphocyte-specific tyrosine kinase was genetically fused to a truncated BCCP, and the resulting fusion protein was labeled through biotinylation with BPL carrying multiple copies of a luminescent Tb(3+) complex. The labeled SH2 fusion proteins were employed to detect a phosphorylated peptide immobilized on the surface of the microtiter plate, where the phosphorylated peptide was produced by phosphorylation to the substrate peptide by Src tyrosine kinase. Our assay allows for a reliable determination of the activity of Src kinase lower than 10 pg/μL by a simple procedure.

Possible generation of heat from nuclear fusion in Earth's inner core.

PubMed

Fukuhara, Mikio

2016-11-23

The cause and source of the heat released from Earth's interior have not yet been determined. Some research groups have proposed that the heat is supplied by radioactive decay or by a nuclear georeactor. Here we postulate that the generation of heat is the result of three-body nuclear fusion of deuterons confined in hexagonal FeDx core-centre crystals; the reaction rate is enhanced by the combined attraction effects of high-pressure (~364 GPa) and high-temperature (~5700 K) and by the physical catalysis of neutral pions: 2 D +  2 D +  2 D → 2 1 H +  4 He + 2  + 20.85 MeV. The possible heat generation rate can be calculated as 8.12 × 10 12  J/m 3 , based on the assumption that Earth's primitive heat supply has already been exhausted. The H and He atoms produced and the anti-neutrino are incorporated as Fe-H based alloys in the H-rich portion of inner core, are released from Earth's interior to the universe, and pass through Earth, respectively.

Effect of particle pinch on the fusion performance and profile features of an international thermonuclear experimental reactor-like fusion reactor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Shijia, E-mail: wangsg@mail.ustc.edu.cn; Wang, Shaojie

2015-04-15

The evolution of the plasma temperature and density in an international thermonuclear experimental reactor (ITER)-like fusion device has been studied by numerically solving the energy transport equation coupled with the particle transport equation. The effect of particle pinch, which depends on the magnetic curvature and the safety factor, has been taken into account. The plasma is primarily heated by the alpha particles which are produced by the deuterium-tritium fusion reactions. A semi-empirical method, which adopts the ITERH-98P(y,2) scaling law, has been used to evaluate the transport coefficients. The fusion performances (the fusion energy gain factor, Q) similar to the ITERmore » inductive scenario and non-inductive scenario (with reversed magnetic shear) are obtained. It is shown that the particle pinch has significant effects on the fusion performance and profiles of a fusion reactor. When the volume-averaged density is fixed, particle pinch can lower the pedestal density by ∼30%, with the Q value and the central pressure almost unchanged. When the particle source or the pedestal density is fixed, the particle pinch can significantly enhance the Q value by  60%, with the central pressure also significantly raised.« less

Fusion of agarase and neoagarobiose hydrolase for mono-sugar production from agar.

PubMed

Alkotaini, Bassam; Han, Nam Soo; Kim, Beom Soo

2017-02-01

In enzymatic saccharification of agar, endo- and exo-agarases together with neoagarobiose hydrolase (NABH) are important key enzymes for the sequential hydrolysis reactions. In this study, a bifunctional endo/exo-agarase was fused with NABH for production of mono-sugars (D-galactose and 3,6-anhydro-L-galactose) from agar using only one fusion enzyme. Two fusion enzymes with either bifunctional agarase (Sco3476) or NABH (Zg4663) at the N-terminus, Sco3476-Zg4663 (SZ) and Zg4663-Sco3476 (ZS), were constructed. Both fusion enzymes exhibited their optimal agarase and NABH activities at 40 and 35 °C, respectively. Fusions SZ and ZS enhanced the thermostability of the NABH activity, while only fusion SZ showed a slight enhancement in the NABH catalytic efficiency (K cat /K M ) from 14.8 (mg/mL) -1  s -1 to 15.8 (mg/mL) -1  s -1 . Saccharification of agar using fusion SZ resulted in 2-fold higher mono-sugar production and 3-fold lower neoagarobiose accumulation when compared to the physical mixture of Sco3476 and Zg4663. Therefore, this fusion has the potential to reduce enzyme production cost, decrease intermediate accumulation, and increase mono-sugar yield in agar saccharification.

Effects of magnetization on fusion product trapping and secondary neutron spectra

DOE PAGES

Knapp, Patrick F.; Schmit, Paul F.; Hansen, Stephanie B.; ...

2015-05-14

In magnetizing the fusion fuel in inertial confinement fusion (ICF) systems, we found that the required stagnation pressure and density can be relaxed dramatically. This happens because the magnetic field insulates the hot fuel from the cold pusher and traps the charged fusion burn products. This trapping allows the burn products to deposit their energy in the fuel, facilitating plasma self-heating. Here, we report on a comprehensive theory of this trapping in a cylindrical DD plasma magnetized with a purely axial magnetic field. Using this theory, we are able to show that the secondary fusion reactions can be used tomore » infer the magnetic field-radius product, BR, during fusion burn. This parameter, not ρR, is the primary confinement parameter in magnetized ICF. Using this method, we analyze data from recent Magnetized Liner InertialFusion experiments conducted on the Z machine at Sandia National Laboratories. Furthermore, we show that in these experiments BR ≈ 0.34(+0.14/-0.06) MG · cm, a ~ 14× increase in BR from the initial value, and confirming that the DD-fusion tritons are magnetized at stagnation. Lastly, this is the first experimental verification of charged burn product magnetization facilitated by compression of an initial seed magnetic flux.« less

Human exploration of space and power development

NASA Technical Reports Server (NTRS)

Cohen, Aaron

1991-01-01

Reasons for mounting the Space Exploration Initiative, the variables facing U.S. planners, and the developmental technologies that will be needed to support this initiative are discussed. The three more advanced technological approaches in the field of power generation described include a lunar-based solar power system, a geosynchronous-based earth orbit solar power satellite system, and the utilization of helium-3/deuterium fusion reaction to create a nuclear fuel cycle. It is noted that the major elements of the SEI will include a heavy-lift launch vehicle, a transfer vehicle and a descent/ascent vehicle for use on lunar missions and adaptable to Mars exploration.

Metabolic Stress and Disorders Related to Alterations in Mitochondrial Fission or Fusion

PubMed Central

Babbar, Mansi; Sheikh, M. Saeed

2014-01-01

Mitochondrial morphology and metabolism play an important role in cellular homeostasis. Recent studies have shown that the fidelity of mitochondrial morphology is important in maintaining mitochondrial shape, number, size, membrane potential, ATP synthesis, mtDNA, motility, signaling, quality control, response to cellular stress, mitophagy and apoptosis. This article provides an overview of the current state of knowledge of the fission and fusion machinery with a focus on the mechanisms underlying the regulation of the mitochondrial morphology and cellular energy state. Several lines of evidence indicate that dysregulation of mitochondrial fission or fusion is associated with mitochondrial dysfunction, which in turn impacts mitophagy and apoptosis. Metabolic disorders are also associated with dysregulation of fission or fusion and the available lines of evidence point to a bidirectional interplay between the mitochondrial fission or fusion reactions and bioenergetics. Clearly, more in-depth studies are needed to fully elucidate the mechanisms that control mitochondrial fission and fusion. It is envisioned that the outcome of such studies will improve the understanding of the molecular basis of related metabolic disorders and also facilitate the development of better therapeutics. PMID:24533171

NSF- and SNARE-mediated membrane fusion is required for nuclear envelope formation and completion of nuclear pore complex assembly in Xenopus laevis egg extracts.

PubMed

Baur, Tina; Ramadan, Kristijan; Schlundt, Andreas; Kartenbeck, Jürgen; Meyer, Hemmo H

2007-08-15

Despite the progress in understanding nuclear envelope (NE) reformation after mitosis, it has remained unclear what drives the required membrane fusion and how exactly this is coordinated with nuclear pore complex (NPC) assembly. Here, we show that, like other intracellular fusion reactions, NE fusion in Xenopus laevis egg extracts is mediated by SNARE proteins that require activation by NSF. Antibodies against Xenopus NSF, depletion of NSF or the dominant-negative NSF(E329Q) variant specifically inhibited NE formation. Staging experiments further revealed that NSF was required until sealing of the envelope was completed. Moreover, excess exogenous alpha-SNAP that blocks SNARE function prevented membrane fusion and caused accumulation of non-flattened vesicles on the chromatin surface. Under these conditions, the nucleoporins Nup107 and gp210 were fully recruited, whereas assembly of FxFG-repeat-containing nucleoporins was blocked. Together, we define NSF- and SNARE-mediated membrane fusion events as essential steps during NE formation downstream of Nup107 recruitment, and upstream of membrane flattening and completion of NPC assembly.

Effect of Ca2+ on Vesicle Fusion on Solid Surface: An In vitro Model of Protein-Accelerated Vesicle Fusion

NASA Astrophysics Data System (ADS)

Shinozaki, Youichi; Siitonen, Ari M.; Sumitomo, Koji; Furukawa, Kazuaki; Torimitsu, Keiichi

2008-07-01

Lipid vesicle fusion is an important reaction in the cell. Calcium ions (Ca2+) participate in various important biological events including the fusion of vesicles with cell membranes in cells. We studied the effect of Ca2+ on the fusion of egg yolk phosphatidylcholine/brain phosphatidylserine (eggPC/brainPS) lipid vesicles on a mica substrate with fast scanning atomic force microscopy (AFM). When unattached and unfused lipid vesicles on mica were rinsed away, discrete patches of fused vesicles were observed under high Ca2+ concentrations. At 0 mM Ca2+, lipid vesicles were fused on mica and formed continuous supported lipid bilayers (SLBs) covering almost the entire mica surface. The effect of Ca2+ on SLB formation was offset by a Ca2+ chelating agent. When lipid vesicles were added during AFM observation, vesicles fused on mica and covered almost all areas even under high Ca2+ concentrations. These results indicate that force between AFM tip and vesicles overcomes the Ca2+-reduced fusion of lipid vesicles.

Solitosynthesis: Cosmological evolution of non-topological solitons

NASA Technical Reports Server (NTRS)

Griest, Kim; Kolb, Edward W.

1989-01-01

The thermal creation, fusion, evaporation, and destruction of non-topological solitons (NTS) after a phase transition in the early universe is considered. By defining and following NTS statistical equilibrium and departures from it, and depending on particle physics parameters, one of three possible scenarios occurs. If reaction rates are high enough, a period of equilibrium occurs and relic abundances are determined by the freeze-out temperature. Equilibrium first drives most NTS's into their constituents (free phi particles) and then causes rapid fusion into large NTS's. If freeze-out occurs during the first phase, the NTS's are almost entirely destroyed, while if it occurs during the second phase, solitosynthesis occurs and NTS's may be cosmically relevant. For slow reaction rates the NTS's are born frozen out and have the abundance determined by the phase transition. Analytic approximations for determining the abundances are developed, and tested by numerically integrating a reaction network in an expanding universe. Unfortunately, for most of the parameter space considered, solito-destruction/evaporation occurs.

Influence of laser power on microstructure and mechanical properties of laser welded-brazed Mg to Ni coated Ti alloys

NASA Astrophysics Data System (ADS)

Tan, Caiwang; Lu, Qingshuang; Chen, Bo; Song, Xiaoguo; Li, Liqun; Feng, Jicai; Wang, Yang

2017-03-01

AZ31B Magnesium (Mg) and Ti-6Al-4V titanium (Ti) alloys with Ni coating were joined by laser welding-brazing process using AZ92 Mg based filler. The influence of laser power on microstructure and mechanical properties were investigated. Ni coating was found to significantly promote good wetting-spreading ability of molten filler on the Ti sheet. Acceptable joints without obvious defects were obtained within a relatively wide processing window. In the process metallurgical bonding was achieved by the formation of Ti3Al phase at direct irradiation zone and Al-Ni phase followed by a layer of Mg-Al-Ni ternary compound adjacent to the fusion zone at the intermediate zone. The thickness of reaction layers increased slowly with the increasing laser power. The tensile-shear test indicated that joints produced at the laser power of 1300 W reached 2387 N fracture load, representing 88.5% joint efficiency with respect to the Mg base metal. The corresponding failure occurred in the fusion zone of the Mg base metal, while joints fractured at the interface at lower/higher laser power due to the crack or excessive intermetallic compound (IMC) formation along the interface.

Observation of a novel stapler band in 75As

NASA Astrophysics Data System (ADS)

Li, C. G.; Chen, Q. B.; Zhang, S. Q.; Xu, C.; Hua, H.; Li, X. Q.; Wu, X. G.; Hu, S. P.; Meng, J.; Xu, F. R.; Liang, W. Y.; Li, Z. H.; Ye, Y. L.; Jiang, D. X.; Sun, J. J.; Han, R.; Niu, C. Y.; Chen, X. C.; Li, P. J.; Wang, C. G.; Wu, H. Y.; Li, G. S.; He, C. Y.; Zheng, Y.; Li, C. B.; Chen, Q. M.; Zhong, J.; Zhou, W. K.

2017-03-01

The heavy ion fusion-evaporation reaction study for the high-spin spectroscopy of 75As has been performed via the reaction channel 70Zn(9Be, 1p3n)75As at a beam energy of 42 MeV. The collective structure especially a dipole band in 75As is established for the first time. The properties of this dipole band are investigated in terms of the self-consistent tilted axis cranking covariant density functional theory. Based on the theoretical description and the examination of the angular momentum components, this dipole band can be interpreted as a novel stapler band, where the valence neutrons in (1g9/2) orbital rather than the collective core are responsible for the closing of the stapler of angular momentum.

An increase in the 12C + 12C fusion rate from resonances at astrophysical energies.

PubMed

Tumino, A; Spitaleri, C; La Cognata, M; Cherubini, S; Guardo, G L; Gulino, M; Hayakawa, S; Indelicato, I; Lamia, L; Petrascu, H; Pizzone, R G; Puglia, S M R; Rapisarda, G G; Romano, S; Sergi, M L; Spartá, R; Trache, L

2018-05-01

Carbon burning powers scenarios that influence the fate of stars, such as the late evolutionary stages of massive stars 1 (exceeding eight solar masses) and superbursts from accreting neutron stars 2,3 . It proceeds through the 12 C +  12 C fusion reactions that produce an alpha particle and neon-20 or a proton and sodium-23-that is, 12 C( 12 C, α) 20 Ne and 12 C( 12 C, p) 23 Na-at temperatures greater than 0.4 × 10 9 kelvin, corresponding to astrophysical energies exceeding a megaelectronvolt, at which such nuclear reactions are more likely to occur in stars. The cross-sections 4 for those carbon fusion reactions (probabilities that are required to calculate the rate of the reactions) have hitherto not been measured at the Gamow peaks 4 below 2 megaelectronvolts because of exponential suppression arising from the Coulomb barrier. The reference rate 5 at temperatures below 1.2 × 10 9 kelvin relies on extrapolations that ignore the effects of possible low-lying resonances. Here we report the measurement of the 12 C( 12 C, α 0,1 ) 20 Ne and 12 C( 12 C, p 0,1 ) 23 Na reaction rates (where the subscripts 0 and 1 stand for the ground and first excited states of 20 Ne and 23 Na, respectively) at centre-of-mass energies from 2.7 to 0.8 megaelectronvolts using the Trojan Horse method 6,7 and the deuteron in 14 N. The cross-sections deduced exhibit several resonances that are responsible for very large increases of the reaction rate at relevant temperatures. In particular, around 5 × 10 8 kelvin, the reaction rate is boosted to more than 25 times larger than the reference value 5 . This finding may have implications such as lowering the temperatures and densities 8 required for the ignition of carbon burning in massive stars and decreasing the superburst ignition depth in accreting neutron stars to reconcile observations with theoretical models 3 .

Hrs regulates early endosome fusion by inhibiting formation of an endosomal SNARE complex

PubMed Central

Sun, Wei; Yan, Qing; Vida, Thomas A.; Bean, Andrew J.

2003-01-01

Movement through the endocytic pathway occurs principally via a series of membrane fusion and fission reactions that allow sorting of molecules to be recycled from those to be degraded. Endosome fusion is dependent on SNARE proteins, although the nature of the proteins involved and their regulation has not been fully elucidated. We found that the endosome-associated hepatocyte responsive serum phosphoprotein (Hrs) inhibited the homotypic fusion of early endosomes. A region of Hrs predicted to form a coiled coil required for binding the Q-SNARE, SNAP-25, mimicked the inhibition of endosome fusion produced by full-length Hrs, and was sufficient for endosome binding. SNAP-25, syntaxin 13, and VAMP2 were bound from rat brain membranes to the Hrs coiled-coil domain. Syntaxin 13 inhibited early endosomal fusion and botulinum toxin/E inhibition of early endosomal fusion was reversed by addition of SNAP-25(150–206), confirming a role for syntaxin 13, and establishing a role for SNAP-25 in endosomal fusion. Hrs inhibited formation of the syntaxin 13–SNAP-25–VAMP2 complex by displacing VAMP2 from the complex. These data suggest that SNAP-25 is a receptor for Hrs on early endosomal membranes and that the binding of Hrs to SNAP-25 on endosomal membranes inhibits formation of a SNARE complex required for homotypic endosome fusion. PMID:12847087

Exploring incomplete fusion fraction in 6,7Li induced nuclear reactions

NASA Astrophysics Data System (ADS)

Parkar, V. V.; Jha, V.; Kailas, S.

2017-11-01

We have included breakup effects explicitly to simultaneously calculate the measured cross-sections of the complete fusion, incomplete fusion, and total fusion for 6,7Li projectiles on various targets using the Continuum Discretized Coupled Channels method. The breakup absorption cross-sections obtained with different choices of short range imaginary potentials are utilized to evaluate the individual α-capture and d/t-capture cross-sections and compare with the measured data. It is interesting to note, while in case of 7Li projectile the cross-sections for triton-ICF/triton-capture is far more dominant than α-ICF/α-capture at all energies, similar behavior is not observed in case of 6Li projectile for the deuteron-ICF/deuteron-capture and α-ICF/α-capture. Both these observations are also corroborated by the experimental data for all the systems studied.

The Probability of Muon Sticking and X-Ray Yields in the Muon Catalyzed Fusion Cycle in a Deuterium and Tritium Mixture

NASA Astrophysics Data System (ADS)

Pahlavani, M. R.; Motevalli, S. M.

2008-03-01

The muon catalyzed fusion cycle in mixtures of deuterium and tritium is of particular interest due to the observation of high fusion yields. In the D-T mixture, the most serious limitation to the efficiency of the fusion chain is the probability of muon sticking to the alpha -particle produced in the nuclear reaction. An accurate kinetic treatment has been applied to the muonic helium atoms formed by a muon sticking to the alpha -particles. In this work accurate rates for collisions of alpha mu + ions with hydrogen atoms have been used for calculation of muon stripping probability and the intensities of X-ray transitions by solving a set of coupled differential equations numerically. Our calculated results are in good agreement with experimental data available in literature.

Sub-barrier radioactive ion beam investigations using a new methodology and analysis for the stacked target technique

NASA Astrophysics Data System (ADS)

Fisichella, M.; Shotter, A. C.; Di Pietro, A.; Figuera, P.; Lattuada, M.; Marchetta, C.; Privitera, V.; Romano, L.; Ruiz, C.; Zadro, M.

2015-12-01

For low energy reaction studies involving radioactive ion beams, the experimental reaction yields are generally small due to the low intensity of the beams. For this reason, the stacked target technique has been often used to measure excitation functions. This technique offers considerable advantages since the reaction cross-section at several energies can be simultaneously measured. In a further effort to increase yields, thick targets are also employed. The main disadvantage of the method is the degradation of the beam quality as it passes through the stack due to the statistical nature of energy loss processes and any nonuniformity of the stacked targets. This degradation can lead to ambiguities of associating effective beam energies to reaction product yields for the targets within the stack and, as a consequence, to an error in the determination of the excitation function for the reaction under study. A thorough investigation of these ambiguities is reported, and a best practice procedure of analyzing data obtained using the stacked target technique with radioactive ion beams is recommended. Using this procedure a re-evaluation is reported of some previously published sub-barrier fusion data in order to demonstrate the possibility of misinterpretations of derived excitation functions. In addition, this best practice procedure has been used to evaluate, from a new data set, the sub-barrier fusion excitation function for the reaction 6Li+120Sn .

Membrane fusion and exocytosis.

PubMed

Jahn, R; Südhof, T C

1999-01-01

Membrane fusion involves the merger of two phospholipid bilayers in an aqueous environment. In artificial lipid bilayers, fusion proceeds by means of defined transition states, including hourglass-shaped intermediates in which the proximal leaflets of the fusing membranes are merged whereas the distal leaflets are separate (fusion stalk), followed by the reversible opening of small aqueous fusion pores. Fusion of biological membranes requires the action of specific fusion proteins. Best understood are the viral fusion proteins that are responsible for merging the viral with the host cell membrane during infection. These proteins undergo spontaneous and dramatic conformational changes upon activation. In the case of the paradigmatic fusion proteins of the influenza virus and of the human immunodeficiency virus, an amphiphilic fusion peptide is inserted into the target membrane. The protein then reorients itself, thus forcing the fusing membranes together and inducing lipid mixing. Fusion of intracellular membranes in eukaryotic cells involves several protein families including SNAREs, Rab proteins, and Sec1/Munc-18 related proteins (SM-proteins). SNAREs form a novel superfamily of small and mostly membrane-anchored proteins that share a common motif of about 60 amino acids (SNARE motif). SNAREs reversibly assemble into tightly packed helical bundles, the core complexes. Assembly is thought to pull the fusing membranes closely together, thus inducing fusion. SM-proteins comprise a family of soluble proteins that bind to certain types of SNAREs and prevent the formation of core complexes. Rab proteins are GTPases that undergo highly regulated GTP-GDP cycles. In their GTP form, they interact with specific proteins, the effector proteins. Recent evidence suggests that Rab proteins function in the initial membrane contact connecting the fusing membranes but are not involved in the fusion reaction itself.

Comprehensive characterization of RSPO fusions in colorectal traditional serrated adenomas.

PubMed

Sekine, Shigeki; Ogawa, Reiko; Hashimoto, Taiki; Motohiro, Kojima; Yoshida, Hiroshi; Taniguchi, Hirokazu; Saito, Yutaka; Yasuhiro, Ohno; Ochiai, Atsushi; Hiraoka, Nobuyoshi

2017-10-01

Traditional serrated adenoma (TSA) is a rare but distinct type of colorectal polyp. Our previous study showed that PTPRK-RSPO3 fusions are frequent and characteristic genetic alterations in TSAs. This study aimed to characterize comprehensively the prevalence and variability of RSPO fusions in colorectal TSAs. We examined RSPO expression and explored novel RSPO fusions in 129 TSAs, including 66 lesions analysed previously for WNT pathway gene mutations. Quantitative polymerase chain reaction (qPCR) analyses identified three and 43 TSAs overexpressing RSPO2 and RSPO3, respectively, whereas the expression of RSPO1 and RSPO4 was marginal or undetectable in all cases. RSPO overexpression was always mutually exclusive with other WNT pathway gene mutations. Known PTPRK-RSPO3 fusions were detected in 37 TSAs, all but one of which overexpressed RSPO3. In addition, rapid amplification of cDNA ends revealed three novel RSPO fusion transcripts, an NRIP1-RSPO2 fusion and two PTPRK-RSPO3 fusion isoforms, in six TSAs. Overall, 43 TSAs had RSPO fusions (33%), whereas four TSAs (3%) overexpressed RSPO in the absence of RSPO fusions. TSAs with RSPO fusions showed several clinicopathological features, including distal localization (P = 0.0063), larger size (P = 0.0055), prominent ectopic crypt foci (P = 8.4 × 10 -4 ), association of a high-grade component (P = 1.1 × 10 -4 ), and the presence of KRAS mutations (P = 4.5 × 10 -5 ). The present study identified RSPO fusion transcripts, including three novel transcripts, in one-third of colorectal TSAs and showed that PTPRK-RSPO3 fusions were the predominant cause of RSPO overexpression in colorectal TSA. © 2017 John Wiley & Sons Ltd.

Neutron-induced reactions relevant for Inertial-Cofinement Fusion Experiments

NASA Astrophysics Data System (ADS)

Boswell, Melissa; Devlin, Mathew; Fotiadis, Nikolaos; Merrill, Frank; Nelson, Ronald; Tonchev, Anton

2014-09-01

The typical ignition experiment at the National Ignition Facility ablatively implodes a plastic capsule filled with DT fuel, generating a high flux of 14-MeV neutrons from the d(t,n) α reaction. There is some spread in the energy of these primary 14-MeV neutrons, which is mainly attributable to Doppler shifting from the relative thermal motion of the burning DT fuel. Neutrons created during this reaction have 5--10% chance of scattering before escaping the fuel assembly, losing some fraction of their energy in the scattering process. Neutrons emerging with an energy greater than the reaction energy are generated by a two-step process where neutrons first transfer momentum to a deuteron or tritium ion, these enhanced energy ions then fuse in flight to produce higher energy neutrons; some of these neutrons have energies in excess of 30 MeV. Measuring the fluencies of both the low- and high-energy neutrons is a powerful mechanism for studying the properties of the fuel assembly, and the various parameters important to inertial confinement fusion. We have developed a number of tools to measure the spectral characteristics of the NIF neutron spectrum. Most of these methods rely on exploiting the energy dependence of (n, γ), (n,2n), (n,3n) and (n,p) reactions on a variety o.

Calculated differential and double differential cross section of DT neutron induced reactions on natural chromium (Cr)

NASA Astrophysics Data System (ADS)

Rajput, Mayank; Vala, Sudhirsinh; Srinivasan, R.; Abhangi, M.; Subhash, P. V.; Pandey, B.; Rao, C. V. S.; Bora, D.

2018-01-01

Chromium is an important alloying element of stainless steel (SS) and SS is the main constituent of structural material proposed for fusion reactors. Energy and double differential cross section data will be required to estimate nuclear responses in the materials used in fusion reactors. There are no experimental data of energy and double differential cross section, available for neutron induced reactions on natural chromium at 14 MeV neutron energy. In this study, energy and double differential cross section data of (n,p) and (n,α) reactions for all the stable isotopes of chromium have been estimated, using appropriate nuclear models in TALYS code. The cross section data of stable isotopes are later converted into the energy and double differential cross section data of natural Cr using the isotopic abundance. The contribution from compound, pre-equilibrium and direct nuclear reaction to total reaction have also been calculated for 52,50Cr(n,p) and 52Cr(n,α). The calculation of energy differential cross section shows that most of emitted protons and alpha particles are of 3 and 8 MeV respectively. The calculated data is compared with the data from EXFOR data library and is found to be in good agreement.

Ultrafast neutron detector

DOEpatents

Wang, C.L.

1985-06-19

A neutron detector of very high temporal resolution is described. It may be used to measure distributions of neutrons produced by fusion reactions that persist for times as short as about 50 picoseconds.

Experimental suprachoroidal plombage with a urethane based hydrophilic polymer.

PubMed Central

Foulds, W. S.; Aitken, D.; Lee, W. R.

1988-01-01

Small portions of dehydrated hydrophilic polymer (HPU 90, Smith and Nephew) have been inserted into the suprachoroidal space in rabbits to investigate the possible use of suprachoroidal plombage in retinal detachment surgery. As it hydrates, the material causes a pronounced elevation of choroid and retina, and the implants have been well tolerated for periods of up to one year in experimental animals. The implant slowly breaks down and stimulates a simple macrophagic reaction: fibrosis in the overlying choroid is associated with ischaemic gliosis and chorioretinal fusion. Images PMID:3378024

Experimental measurement of the 12C+16O fusion cross sections at astrophysical energies

NASA Astrophysics Data System (ADS)

Fang, X.; Tan, W. P.; Beard, M.; deBoer, R. J.; Gilardy, G.; Jung, H.; Liu, Q.; Lyons, S.; Robertson, D.; Setoodehnia, K.; Seymour, C.; Stech, E.; Vande Kolk, B.; Wiescher, M.; de Souza, R.; Hudan, S.; Singh, V.; Tang, X. D.; Uberseder, E.

2018-05-01

The total cross sections of the 12C+16O fusion have been experimentally determined at low energies to investigate the role of this reaction during late stellar evolution burning phases. A high-intensity oxygen beam was produced by the 5MV pelletron accelerator at the University of Notre Dame impinging on a thick ultra-pure graphite target. Protons and γ-rays were measured simultaneously in the center-of-mass energy range from 3.64 to 5.01 MeV, using strip silicon and HPGe detectors. Statistical model calculations were employed to interpret the experimental results. A new broad resonance-like structure is observed for the 12C+16O reaction, and a decreasing trend of its S-factor towards low energies is found.

Detection of EML4-ALK fusion gene and features associated with EGFR mutations in Chinese patients with non-small-cell lung cancer.

PubMed

Wen, Miaomiao; Wang, Xuejiao; Sun, Ying; Xia, Jinghua; Fan, Liangbo; Xing, Hao; Zhang, Zhipei; Li, Xiaofei

2016-01-01

Echinoderm microtubule-associated protein-like 4-anaplastic lymphoma kinase (EML4-ALK) and epidermal growth factor receptor (EGFR) define specific molecular subsets of lung cancer with distinct clinical features. We aimed at revealing the clinical features of EML4-ALK fusion gene and EGFR mutation in non-small-cell lung cancer (NSCLC). We enrolled 694 Chinese patients with NSCLC for analysis. EML4-ALK fusion gene was analyzed by real-time polymerase chain reaction, and EGFR mutations were analyzed by amplified refractory mutation system. Among the 694 patients, 60 (8.65%) patients had EML4-ALK fusions. In continuity correction χ (2) test analysis, EML4-ALK fusion gene was correlated with sex, age, smoking status, and histology, but no significant association was observed between EML4-ALK fusion gene and clinical stage. A total of 147 (21.18%) patients had EGFR mutations. In concordance with previous reports, EGFR mutation was correlated with age, smoking status, histology, and clinical stage, whereas patient age was not significantly associated with EGFR mutation. Meanwhile, to our surprise, six (0.86%) patients had coexisting EML4-ALK fusions and EGFR mutations. EML4-ALK fusion gene defines a new molecular subset in patients with NSCLC. Six patients who harbored both EML4-ALK fusion genes and EGFR mutations were identified in our study. The EGFR mutations and the EML4-ALK fusion genes are coexistent.

Detection of EML4-ALK fusion gene and features associated with EGFR mutations in Chinese patients with non-small-cell lung cancer

PubMed Central

Wen, Miaomiao; Wang, Xuejiao; Sun, Ying; Xia, Jinghua; Fan, Liangbo; Xing, Hao; Zhang, Zhipei; Li, Xiaofei

2016-01-01

Purpose Echinoderm microtubule-associated protein-like 4–anaplastic lymphoma kinase (EML4-ALK) and epidermal growth factor receptor (EGFR) define specific molecular subsets of lung cancer with distinct clinical features. We aimed at revealing the clinical features of EML4-ALK fusion gene and EGFR mutation in non-small-cell lung cancer (NSCLC). Methods We enrolled 694 Chinese patients with NSCLC for analysis. EML4-ALK fusion gene was analyzed by real-time polymerase chain reaction, and EGFR mutations were analyzed by amplified refractory mutation system. Results Among the 694 patients, 60 (8.65%) patients had EML4-ALK fusions. In continuity correction χ2 test analysis, EML4-ALK fusion gene was correlated with sex, age, smoking status, and histology, but no significant association was observed between EML4-ALK fusion gene and clinical stage. A total of 147 (21.18%) patients had EGFR mutations. In concordance with previous reports, EGFR mutation was correlated with age, smoking status, histology, and clinical stage, whereas patient age was not significantly associated with EGFR mutation. Meanwhile, to our surprise, six (0.86%) patients had coexisting EML4-ALK fusions and EGFR mutations. Conclusion EML4-ALK fusion gene defines a new molecular subset in patients with NSCLC. Six patients who harbored both EML4-ALK fusion genes and EGFR mutations were identified in our study. The EGFR mutations and the EML4-ALK fusion genes are coexistent. PMID:27103824

Development of fusogenic glass surfaces that impart spatiotemporal control over macrophage fusion: Direct visualization of multinucleated giant cell formation

PubMed Central

Faust, James J.; Christenson, Wayne; Doudrick, Kyle; Ros, Robert

2017-01-01

Implantation of synthetic material, including vascular grafts, pacemakers, etc. results in the foreign body reaction and the formation of multinucleated giant cells (MGCs) at the exterior surface of the implant. Despite the long-standing premise that fusion of mononucleated macrophages results in the formation of MGCs, to date, no published study has shown fusion in context with living specimens. This is due to the fact that optical-quality glass, which is required for the majority of live imaging techniques, does not promote macrophage fusion. Consequently, the morphological changes that macrophages undergo during fusion as well as the mechanisms that govern this process remain ill-defined. In this study, we serendipitously identified a highly fusogenic glass surface and discovered that the capacity to promote fusion was due to oleamide contamination. When adsorbed on glass, oleamide and other molecules that contain long-chain hydrocarbons promoted high levels of macrophage fusion. Adhesion, an essential step for macrophage fusion, was apparently mediated by Mac-1 integrin (CD11b/CD18, αMβ2) as determined by single cell force spectroscopy and adhesion assays. Micropatterned glass further increased fusion and enabled a remarkable degree of spatiotemporal control over MGC formation. Using these surfaces, we reveal the kinetics that govern MGC formation in vitro. We anticipate that the spatiotemporal control afforded by these surfaces will expedite studies designed to identify the mechanism(s) of macrophage fusion and MGC formation with implication for the design of novel biomaterials. PMID:28340410

Combining MHD Airbreathing and Fusion Rocket Propulsion for Earth-to-Orbit Flight

NASA Astrophysics Data System (ADS)

Froning, H. D.; Miley, G. H.; Luo, Nie; Yang, Yang; Momota, H.; Burton, E.

2005-02-01

Previous studies have shown that Single-State-to-Orbit (SSTO) vehicle propellant can be reduced by Magnets-Hydro-Dynamic (MHD) processes that minimize airbreathing propulsion losses and propellant consumption during atmospheric flight. Similarly additional reduction in SSTO propellant is enabled by Inertial Electrostatic Confinement (IEC) fusion, whose more energetic reactions reduce rocket propellant needs. MHD airbreathing propulsion during an SSTO vehicle's initial atmospheric flight phase and IEC fusion propulsion during its final exo-atmospheric flight phase is therefore being explored. Accomplished work is not yet sufficient for claiming such a vehicle's feasibility. But takeoff and propellant mass for an MHD airbreathing and IEC fusion vehicle could be as much as 25 and 40 percent less than one with ordinary airbreathing and IEC fusion; and as much as 50 and 70 percent less than SSTO takeoff and propellant mass with MHD airbreathing and chemical rocket propulsion. Thus this unusual combined cycle engine shows great promise for performance gains beyond contemporary combined-cycle airbreathing engines.

Characterization of a deuterium-deuterium plasma fusion neutron generator

NASA Astrophysics Data System (ADS)

Lang, R. F.; Pienaar, J.; Hogenbirk, E.; Masson, D.; Nolte, R.; Zimbal, A.; Röttger, S.; Benabderrahmane, M. L.; Bruno, G.

2018-01-01

We characterize the neutron output of a deuterium-deuterium plasma fusion neutron generator, model 35-DD-W-S, manufactured by NSD/Gradel-Fusion. The measured energy spectrum is found to be dominated by neutron peaks at 2.2 MeV and 2.7 MeV. A detailed GEANT4 simulation accurately reproduces the measured energy spectrum and confirms our understanding of the fusion process in this generator. Additionally, a contribution of 14 . 1 MeV neutrons from deuterium-tritium fusion is found at a level of 3 . 5%, from tritium produced in previous deuterium-deuterium reactions. We have measured both the absolute neutron flux as well as its relative variation on the operational parameters of the generator. We find the flux to be proportional to voltage V 3 . 32 ± 0 . 14 and current I 0 . 97 ± 0 . 01. Further, we have measured the angular dependence of the neutron emission with respect to the polar angle. We conclude that it is well described by isotropic production of neutrons within the cathode field cage.

α-SNAP Interferes with the Zippering of the SNARE Protein Membrane Fusion Machinery

PubMed Central

Park, Yongsoo; Vennekate, Wensi; Yavuz, Halenur; Preobraschenski, Julia; Hernandez, Javier M.; Riedel, Dietmar; Walla, Peter Jomo; Jahn, Reinhard

2014-01-01

Neuronal exocytosis is mediated by soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins. Before fusion, SNARE proteins form complexes bridging the membrane followed by assembly toward the C-terminal membrane anchors, thus initiating membrane fusion. After fusion, the SNARE complex is disassembled by the AAA-ATPase N-ethylmaleimide-sensitive factor that requires the cofactor α-SNAP to first bind to the assembled SNARE complex. Using chromaffin granules and liposomes we now show that α-SNAP on its own interferes with the zippering of membrane-anchored SNARE complexes midway through the zippering reaction, arresting SNAREs in a partially assembled trans-complex and preventing fusion. Intriguingly, the interference does not result in an inhibitory effect on synaptic vesicles, suggesting that membrane properties also influence the final outcome of α-SNAP interference with SNARE zippering. We suggest that binding of α-SNAP to the SNARE complex affects the ability of the SNARE complex to harness energy or transmit force to the membrane. PMID:24778182

The choice of the energy embedding law in the design of heavy ionic fusion cylindrical targets

NASA Astrophysics Data System (ADS)

Dolgoleva, GV; Zykova, A. I.

2017-10-01

The paper considers the numerical design of heavy ion fusion (FIHIF) targets, which is one of the branches of controlled thermonuclear fusion (CTF). One of the important tasks in the targets design for controlled thermonuclear fusion is the energy embedding selection whereby it is possible to obtain “burning” (the presence of thermonuclear reactions) of the working DT region. The work is devoted to the rapid ignition of FIHIF targets by means of an additional short-term energy contribution to the DT substance already compressed by massively more longer by energy embedding. This problem has been fairly well studied for laser targets, but this problem is new for heavy ion fusion targets. Maximum momentum increasing is very technically difficult and expensive on modern FIHIF installations. The work shows that the additional energy embedding (“igniting” impulse) reduces the requirements to the maximum impulse. The purpose of this work is to research the ignition impulse effect on the FIHIF target parameters.

Design Study of DESCANT - DEuterated SCintillator Array for Neutron Tagging

NASA Astrophysics Data System (ADS)

Wong, James; Garrett, P. E.

2007-10-01

The fusion-evaporation reaction has been a useful tool for studying nuclei. A program of such reactions is being planned to take place at the TRIUMF facility in Vancouver, Canada using the TIGRESS array of gamma-ray detectors. A particular advantage of using these reactions is that they probe nuclei at moderate-to-high angular momenta. It would be of great interest to extend the study of high-spin states to neutron-rich systems. Following the formation of the fused compound system, the highly-excited state may lose energy by ``evaporating'' particles. Neutron evaporation is the predominant decay mode from neutron-rich compound systems so neutron detectors will be required. The probability of neutrons multiple scattering is quite high so a detector array must be able to differentiate between multiple neutrons evaporating from the reaction and a single neutron scattering multiple times. To address this issue we investigate the use of a novel neutron detector array -- one based on an array of deuterated liquid scintillators as neutron detectors. Results from early feasibility tests will be presented, along with the status of our GEANT4 simulations of the array performance.

The Fusion Gain Analysis of the Inductively Driven Liner Compression Based Fusion

NASA Astrophysics Data System (ADS)

Shimazu, Akihisa; Slough, John

2016-10-01

An analytical analysis of the fusion gain expected in the inductively driven liner compression (IDLC) based fusion is conducted to identify the fusion gain scaling at various operating conditions. The fusion based on the IDLC is a magneto-inertial fusion concept, where a Field-Reversed Configuration (FRC) plasmoid is compressed via the inductively-driven metal liner to drive the FRC to fusion conditions. In the past, an approximate scaling law for the expected fusion gain for the IDLC based fusion was obtained under the key assumptions of (1) D-T fuel at 5-40 keV, (2) adiabatic scaling laws for the FRC dynamics, (3) FRC energy dominated by the pressure balance with the edge magnetic field at the peak compression, and (4) the liner dwell time being liner final diameter divided by the peak liner velocity. In this study, various assumptions made in the previous derivation is relaxed to study the change in the fusion gain scaling from the previous result of G ml1 / 2 El11 / 8 , where ml is the liner mass and El is the peak liner kinetic energy. The implication from the modified fusion gain scaling on the performance of the IDLC fusion reactor system is also explored.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kirkpatrick, R. C.

Nuclear fusion was discovered experimentally in 1933-34 and other charged particle nuclear reactions were documented shortly thereafter. Work in earnest on the fusion ignition problem began with Edward Teller's group at Los Alamos during the war years. His group quantified all the important basic atomic and nuclear processes and summarized their interactions. A few years later, the success of the early theory developed at Los Alamos led to very successful thermonuclear weapons, but also to decades of unsuccessful attempts to harness fusion as an energy source of the future. The reasons for this history are many, but it seems appropriatemore » to review some of the basics with the objective of identifying what is essential for success and what is not. This tutorial discusses only the conditions required for ignition in small fusion targets and how the target design impacts driver requirements. Generally speaking, the driver must meet the energy, power and power density requirements needed by the fusion target. The most relevant parameters for ignition of the fusion fuel are the minimum temperature and areal density (rhoR), but these parameters set secondary conditions that must be achieved, namely an implosion velocity, target size and pressure, which are interrelated. Despite the apparent simplicity of inertial fusion targets, there is not a single mode of fusion ignition, and the necessary combination of minimum temperature and areal density depends on the mode of ignition. However, by providing a magnetic field of sufficient strength, the conditions needed for fusion ignition can be drastically altered. Magnetized target fusion potentially opens up a vast parameter space between the extremes of magnetic and inertial fusion.« less

Entropic forces drive self-organization and membrane fusion by SNARE proteins

PubMed Central

Stratton, Benjamin S.; Warner, Jason M.; Rothman, James E.; O’Shaughnessy, Ben

2017-01-01

SNARE proteins are the core of the cell’s fusion machinery and mediate virtually all known intracellular membrane fusion reactions on which exocytosis and trafficking depend. Fusion is catalyzed when vesicle-associated v-SNAREs form trans-SNARE complexes (“SNAREpins”) with target membrane-associated t-SNAREs, a zippering-like process releasing ∼65 kT per SNAREpin. Fusion requires several SNAREpins, but how they cooperate is unknown and reports of the number required vary widely. To capture the collective behavior on the long timescales of fusion, we developed a highly coarse-grained model that retains key biophysical SNARE properties such as the zippering energy landscape and the surface charge distribution. In simulations the ∼65-kT zippering energy was almost entirely dissipated, with fully assembled SNARE motifs but uncomplexed linker domains. The SNAREpins self-organized into a circular cluster at the fusion site, driven by entropic forces that originate in steric–electrostatic interactions among SNAREpins and membranes. Cooperative entropic forces expanded the cluster and pulled the membranes together at the center point with high force. We find that there is no critical number of SNAREs required for fusion, but instead the fusion rate increases rapidly with the number of SNAREpins due to increasing entropic forces. We hypothesize that this principle finds physiological use to boost fusion rates to meet the demanding timescales of neurotransmission, exploiting the large number of v-SNAREs available in synaptic vesicles. Once in an unfettered cluster, we estimate ≥15 SNAREpins are required for fusion within the ∼1-ms timescale of neurotransmitter release. PMID:28490503

Monte Carlo isotopic inventory analysis for complex nuclear systems

NASA Astrophysics Data System (ADS)

Phruksarojanakun, Phiphat

Monte Carlo Inventory Simulation Engine (MCise) is a newly developed method for calculating isotopic inventory of materials. It offers the promise of modeling materials with complex processes and irradiation histories, which pose challenges for current, deterministic tools, and has strong analogies to Monte Carlo (MC) neutral particle transport. The analog method, including considerations for simple, complex and loop flows, is fully developed. In addition, six variance reduction tools provide unique capabilities of MCise to improve statistical precision of MC simulations. Forced Reaction forces an atom to undergo a desired number of reactions in a given irradiation environment. Biased Reaction Branching primarily focuses on improving statistical results of the isotopes that are produced from rare reaction pathways. Biased Source Sampling aims at increasing frequencies of sampling rare initial isotopes as the starting particles. Reaction Path Splitting increases the population by splitting the atom at each reaction point, creating one new atom for each decay or transmutation product. Delta Tracking is recommended for high-frequency pulsing to reduce the computing time. Lastly, Weight Window is introduced as a strategy to decrease large deviations of weight due to the uses of variance reduction techniques. A figure of merit is necessary to compare the efficiency of different variance reduction techniques. A number of possibilities for figure of merit are explored, two of which are robust and subsequently used. One is based on the relative error of a known target isotope (1/R 2T) and the other on the overall detection limit corrected by the relative error (1/DkR 2T). An automated Adaptive Variance-reduction Adjustment (AVA) tool is developed to iteratively define parameters for some variance reduction techniques in a problem with a target isotope. Sample problems demonstrate that AVA improves both precision and accuracy of a target result in an efficient manner. Potential applications of MCise include molten salt fueled reactors and liquid breeders in fusion blankets. As an example, the inventory analysis of a liquid actinide fuel in the In-Zinerator, a sub-critical power reactor driven by a fusion source, is examined. The result reassures MCise as a reliable tool for inventory analysis of complex nuclear systems.

Self-similar structure and experimental signatures of suprathermal ion distribution in inertial confinement fusion implosions

DOE PAGES

Kagan, Grigory; Svyatskiy, D.; Rinderknecht, H. G.; ...

2015-09-03

The distribution function of suprathermal ions is found to be self-similar under conditions relevant to inertial confinement fusion hot spots. By utilizing this feature, interference between the hydrodynamic instabilities and kinetic effects is for the first time assessed quantitatively to find that the instabilities substantially aggravate the fusion reactivity reduction. Thus, the ion tail depletion is also shown to lower the experimentally inferred ion temperature, a novel kinetic effect that may explain the discrepancy between the exploding pusher experiments and rad-hydro simulations and contribute to the observation that temperature inferred from DD reaction products is lower than from DT atmore » the National Ignition Facility.« less

Self-Similar Structure and Experimental Signatures of Suprathermal Ion Distribution in Inertial Confinement Fusion Implosions

NASA Astrophysics Data System (ADS)

Kagan, Grigory; Svyatskiy, D.; Rinderknecht, H. G.; Rosenberg, M. J.; Zylstra, A. B.; Huang, C.-K.; McDevitt, C. J.

2015-09-01

The distribution function of suprathermal ions is found to be self-similar under conditions relevant to inertial confinement fusion hot spots. By utilizing this feature, interference between the hydrodynamic instabilities and kinetic effects is for the first time assessed quantitatively to find that the instabilities substantially aggravate the fusion reactivity reduction. The ion tail depletion is also shown to lower the experimentally inferred ion temperature, a novel kinetic effect that may explain the discrepancy between the exploding pusher experiments and rad-hydro simulations and contribute to the observation that temperature inferred from DD reaction products is lower than from DT at the National Ignition Facility.

Sputtering, Plasma Chemistry, and RF Sheath Effects in Low-Temperature and Fusion Plasma Modeling

NASA Astrophysics Data System (ADS)

Jenkins, Thomas G.; Kruger, Scott E.; McGugan, James M.; Pankin, Alexei Y.; Roark, Christine M.; Smithe, David N.; Stoltz, Peter H.

2016-09-01

A new sheath boundary condition has been implemented in VSim, a plasma modeling code which makes use of both PIC/MCC and fluid FDTD representations. It enables physics effects associated with DC and RF sheath formation - local sheath potential evolution, heat/particle fluxes, and sputtering effects on complex plasma-facing components - to be included in macroscopic-scale plasma simulations that need not resolve sheath scale lengths. We model these effects in typical ICRF antenna operation scenarios on the Alcator C-Mod fusion device, and present comparisons of our simulation results with experimental data together with detailed 3D animations of antenna operation. Complex low-temperature plasma chemistry modeling in VSim is facilitated by MUNCHKIN, a standalone python/C++/SQL code that identifies possible reaction paths for a given set of input species, solves 1D rate equations for the ensuing system's chemical evolution, and generates VSim input blocks with appropriate cross-sections/reaction rates. These features, as well as principal path analysis (to reduce the number of simulated chemical reactions while retaining accuracy) and reaction rate calculations from user-specified distribution functions, will also be demonstrated. Supported by the U.S. Department of Energy's SBIR program, Award DE-SC0009501.

Large Plasma Membrane Disruptions Are Rapidly Resealed by Ca2+-dependent Vesicle–Vesicle Fusion Events

PubMed Central

Terasaki, Mark; Miyake, Katsuya; McNeil, Paul L.

1997-01-01

A microneedle puncture of the fibroblast or sea urchin egg surface rapidly evokes a localized exocytotic reaction that may be required for the rapid resealing that follows this breach in plasma membrane integrity (Steinhardt, R.A,. G. Bi, and J.M. Alderton. 1994. Science (Wash. DC). 263:390–393). How this exocytotic reaction facilitates the resealing process is unknown. We found that starfish oocytes and sea urchin eggs rapidly reseal much larger disruptions than those produced with a microneedle. When an ∼40 by 10 μm surface patch was torn off, entry of fluorescein stachyose (FS; 1,000 mol wt) or fluorescein dextran (FDx; 10,000 mol wt) from extracellular sea water (SW) was not detected by confocal microscopy. Moreover, only a brief (∼5–10 s) rise in cytosolic Ca2+ was detected at the wound site. Several lines of evidence indicate that intracellular membranes are the primary source of the membrane recruited for this massive resealing event. When we injected FS-containing SW deep into the cells, a vesicle formed immediately, entrapping within its confines most of the FS. DiI staining and EM confirmed that the barrier delimiting injected SW was a membrane bilayer. The threshold for vesicle formation was ∼3 mM Ca2+ (SW is ∼10 mM Ca2+). The capacity of intracellular membranes for sealing off SW was further demonstrated by extruding egg cytoplasm from a micropipet into SW. A boundary immediately formed around such cytoplasm, entrapping FDx or FS dissolved in it. This entrapment did not occur in Ca2+-free SW (CFSW). When egg cytoplasm stratified by centrifugation was exposed to SW, only the yolk platelet–rich domain formed a membrane, suggesting that the yolk platelet is a critical element in this response and that the ER is not required. We propose that plasma membrane disruption evokes Ca2+ regulated vesicle–vesicle (including endocytic compartments but possibly excluding ER) fusion reactions. The function in resealing of this cytoplasmic fusion reaction is to form a replacement bilayer patch. This patch is added to the discontinuous surface bilayer by exocytotic fusion events. PMID:9314529

Reaction dynamics near the barrier

NASA Astrophysics Data System (ADS)

Loveland, W.

2011-10-01

The availability of modest intensity (103-107 p/s) radioactive nuclear beams has had a significant impact on the study of nuclear reactions near the interaction barrier. The role of isospin in capture reactions is a case in point. Using heavy elements as a laboratory to explore these effects, we note that the cross section for producing an evaporation residue is σEVR(Ec . m .) = ∑ J = 0 JmaxσCN(Ec . m . , J) Wsur(Ec . m . , J) where σCN is the complete fusion cross section and Wsur is the survival probability of the completely fused system. The complete fusion cross section can be written as, σCN(Ec . m .) = ∑ J = 0 Jmaxσcapture(Ec . m .) PCN(Ec . m . , J) where σcapture(Ec.m.,J) is the ``capture'' cross section at center-of mass energy Ec.m. and spin J and PCN is the probability that the projectile-target system will evolve inside the fission saddle point to form a completely fused system rather than re-separating (quasi-fission). The systematics of the isospin dependence of the capture cross sections has been developed and the deduced interaction barriers for all known studies of capture cross sections with radioactive beams are in good agreement with recent predictions of an improved QMD model and semi-empirical models. The deduced barriers for these n-rich systems are lower than one would expect from the Bass or proximity potentials. In addition to the barrier lowering, there is an enhanced sub-barrier cross section in these n-rich systems that is of advantage in the synthesis of new heavy nuclei. Recent studies of the ``inverse fission'' of uranium (124,132Sn + 100Mo) have yielded unexpectedly low upper limits for this process due apparently to low values of the fusion probability, PCN. The fusion of halo nuclei, like 11Li with heavy nuclei, like 208Pb, promises to give new information about these and related nuclei and has led/may lead to unusual reaction mechanisms. This work was sponsored, in part, by the USDOE Office of Nuclear Physics.

Multi-focus image fusion based on window empirical mode decomposition

NASA Astrophysics Data System (ADS)

Qin, Xinqiang; Zheng, Jiaoyue; Hu, Gang; Wang, Jiao

2017-09-01

In order to improve multi-focus image fusion quality, a novel fusion algorithm based on window empirical mode decomposition (WEMD) is proposed. This WEMD is an improved form of bidimensional empirical mode decomposition (BEMD), due to its decomposition process using the adding window principle, effectively resolving the signal concealment problem. We used WEMD for multi-focus image fusion, and formulated different fusion rules for bidimensional intrinsic mode function (BIMF) components and the residue component. For fusion of the BIMF components, the concept of the Sum-modified-Laplacian was used and a scheme based on the visual feature contrast adopted; when choosing the residue coefficients, a pixel value based on the local visibility was selected. We carried out four groups of multi-focus image fusion experiments and compared objective evaluation criteria with other three fusion methods. The experimental results show that the proposed fusion approach is effective and performs better at fusing multi-focus images than some traditional methods.

Formation and decay analysis of Cd *48 98 ,104 isotopes in 40Ca20-induced reactions

NASA Astrophysics Data System (ADS)

Gautam, Manjeet Singh; Kaur, Amandeep; Sharma, Manoj K.

2015-11-01

We have analyzed the fusion dynamics of Ca4020+Ni 28 58 ,64 reactions by using the energy dependent Woods-Saxon potential (EDWSP) model and coupled channel model and subsequently the decay patterns of Cd *48 98 ,104 nuclei are governed via the dynamical cluster-decay model (DCM). The influence of intrinsic degrees of freedom of colliding pairs, such as low lying surface vibrations and neutron transfer channels, are entertained within the context of coupled channel calculations. Interestingly, the energy dependence in the Woods-Saxon potential induces barrier modification effects (barrier height, barrier position, barrier curvature) in a somewhat similar way as that for coupled channel approach, hence adequately explains the observed fusion dynamics of Ca4020+Ni 28 58 ,64 reactions. In addition, the decay analysis of compound nuclei formed in the fusion of Ca4020+Ni 28 58 ,64 reactions is investigated by using DCM. The calculations are done for quadrupole (β2) deformed fragments having optimum orientations for hot configurations. The experimental data for evaporation residues lying within the wide range of center of mass energy (Ec .m .) of 64 -88 MeV is nicely addressed using the collective clusterization approach of the DCM. The comparative analysis of decay profiles of Cd *48 98 ,104 is worked out by introducing angular momentum and temperature effects in the fragmentation potential and preformation factor.

Systematic study of probable projectile-target combinations for the synthesis of the superheavy nucleus 302120

NASA Astrophysics Data System (ADS)

Santhosh, K. P.; Safoora, V.

2016-08-01

Probable projectile-target combinations for the synthesis of the superheavy element 302120 have been studied taking the Coulomb and proximity potential as the interaction barrier. The probabilities of the compound nucleus formation PCN for the projectile-target combinations found in the cold reaction valley of 302120 are estimated. At energies near and above the Coulomb barrier, we have calculated the capture, fusion, and evaporation residue cross sections for the reactions of all probable projectile-target combinations so as to predict the most promising projectile-target combinations for the synthesis of the superheavy element 302120 in heavy-ion fusion reactions. The calculated fusion and evaporation cross sections for the more asymmetric ("hotter") projectile-target combination is found to be higher than the less asymmetric ("colder") combination. It can be seen from the nature of the quasifission barrier height, mass asymmetry, the probability of compound nucleus formation, survival probability, and excitation energy, the systems 44Ar+258No , 46Ar+256No , 48Ca+254Fm , 50Ca+252Fm , 54Ti+248Cf , and 58Cr+244Cm in deep region I of the cold reaction valley and the systems 62Fe+240Pu , 64Fe+238Pu , 68Ni+234U , 70Ni+232U , 72Ni+230U , and 74Zn+228Th in the other cold valleys are identified as the better projectile-target combinations for the synthesis of 302120. Our predictions on the synthesis of 302120 superheavy nuclei using the combinations 54Cr+248Cm , 58Fe+244Pu , 64Ni+238U , and 50Ti+249Cf are compared with available experimental data and other theoretical predictions.

Newly Designed Break-Apart and ASPL-TFE3 Dual-Fusion FISH Assay Are Useful in Diagnosing Xp11.2 Translocation Renal Cell Carcinoma and ASPL-TFE3 Renal Cell Carcinoma

PubMed Central

Chen, Xiancheng; Yang, Yang; Gan, Weidong; Xu, Linfeng; Ye, Qing; Guo, Hongqian

2015-01-01

Abstract The diagnosis of Xp11.2 translocation renal cell carcinoma (tRCC), which relies on morphology and immunohistochemistry (IHC), is often either missed in the diagnosis or misdiagnosed. To improve the accuracy of diagnosis of Xp11.2 tRCC and ASPL-TFE3 renal cell carcinoma (RCC), we investigated newly designed fluorescence in situ hybridization (FISH) probes (diagnostic accuracy study). Based on the genetic characteristics of Xp11.2 tRCC and the ASPL-TFE3 RCC, a new break-apart TFE3 FISH probe and an ASPL-TFE3 dual-fusion FISH probe were designed and applied to 65 patients with RCC who were <45 years old or showed suspicious microscopic features of Xp11.2 tRCC in our hospital. To test the accuracy of the probes, we further performed reverse transcriptase–polymerase chain reaction (PCR) on 8 cases for which frozen tissues were available. Among the 65 cases diagnosed with RCC, TFE3 IHC was positive in 24 cases. Twenty-two cases were confirmed as Xp11.2 tRCC by break-apart TFE3 FISH, and 6 of these cases were further diagnosed as ASPL-TFE3 RCC by ASPL-TFE3 dual-fusion FISH detection. Importantly, reverse transcriptase–PCR showed concordant results with the results of FISH assay in the 8 available frozen cases. The break-apart and ASPL-TFE3 dual-fusion FISH assay can accurately detect the translocation of the TFE3 gene and ASPL-TFE3 fusion gene and can thus serve as a valid complementary method for diagnosing Xp11.2 tRCC and ASPL-TFE3 RCC. PMID:25984679

Newly designed break-apart and ASPL-TFE3 dual-fusion FISH assay are useful in diagnosing Xp11.2 translocation renal cell carcinoma and ASPL-TFE3 renal cell carcinoma: a STARD-compliant article.

PubMed

Chen, Xiancheng; Yang, Yang; Gan, Weidong; Xu, Linfeng; Ye, Qing; Guo, Hongqian

2015-05-01

The diagnosis of Xp11.2 translocation renal cell carcinoma (tRCC), which relies on morphology and immunohistochemistry (IHC), is often either missed in the diagnosis or misdiagnosed. To improve the accuracy of diagnosis of Xp11.2 tRCC and ASPL-TFE3 renal cell carcinoma (RCC), we investigated newly designed fluorescence in situ hybridization (FISH) probes (diagnostic accuracy study).Based on the genetic characteristics of Xp11.2 tRCC and the ASPL-TFE3 RCC, a new break-apart TFE3 FISH probe and an ASPL-TFE3 dual-fusion FISH probe were designed and applied to 65 patients with RCC who were <45 years old or showed suspicious microscopic features of Xp11.2 tRCC in our hospital. To test the accuracy of the probes, we further performed reverse transcriptase-polymerase chain reaction (PCR) on 8 cases for which frozen tissues were available.Among the 65 cases diagnosed with RCC, TFE3 IHC was positive in 24 cases. Twenty-two cases were confirmed as Xp11.2 tRCC by break-apart TFE3 FISH, and 6 of these cases were further diagnosed as ASPL-TFE3 RCC by ASPL-TFE3 dual-fusion FISH detection. Importantly, reverse transcriptase-PCR showed concordant results with the results of FISH assay in the 8 available frozen cases.The break-apart and ASPL-TFE3 dual-fusion FISH assay can accurately detect the translocation of the TFE3 gene and ASPL-TFE3 fusion gene and can thus serve as a valid complementary method for diagnosing Xp11.2 tRCC and ASPL-TFE3 RCC.

First Direct Measurement of C 12 ( C 12 , n ) Mg 23 at Stellar Energies

DOE PAGES

Bucher, B.; Tang, X. D.; Fang, X.; ...

2015-06-25

Neutrons produced by the carbon fusion reaction 12C( 12C,n) 23Mg play an important role in stellar nucleosynthesis. However, past studies have shown large discrepancies between experimental data and theory, leading to an uncertain cross section extrapolation at astrophysical energies. Here in this paper, we present the first direct measurement that extends deep into the astrophysical energy range along with a new and improved extrapolation technique based on experimental data from the mirror reaction 12C( 12C,p) 23Na . The new reaction rate has been determined with a well-defined uncertainty that exceeds the precision required by astrophysics models. Using our constrained rate,more » we find that 12C ( 12C,n) 23Mg is crucial to the production of Na and Al in pop-III pair instability supernovae. It also plays a nonnegligible role in the production of weak s -process elements, as well as in the production of the important galactic γ-ray emitter 60Fe.« less

Measuring radial profiles of nuclear burn in ICF implosions at OMEGA and the NIF using proton emission imaging

NASA Astrophysics Data System (ADS)

Seguin, F. H.; Rinderknecht, H. G.; Rosenberg, M.; Zylstra, A.; Frenje, J.; Li, C. K.; Petrasso, R.; Marshall, F. J.; Sangster, T. C.; Hoffman, N. M.; Amendt, P. A.; Bellei, C.; Le Pape, S.; Wilks, S. C.

2014-10-01

Fusion reactions in ICF implosions of D3He-filled capsules produce 14.7-MeV D3He protons and 3-MeV DD protons. Measurements of the spatial distributions of the D3He and DD reactions are studied with a penumbral imaging system that utilizes a CR-39-based imaging detector to simultaneously record separate penumbral images of the two types of protons. Measured burn profiles are useful for studying implosion physics and provide a critical test for benchmarking simulations. Recent implosions at OMEGA of CD capsules containing 3He gas fill and SiO2 capsules containing low-pressure D3He gas were expected to have hollow D3He burn profiles (in the 3He-filled capsule, due to fuel-shell mix), but penumbral imaging showed that the reactions were centrally peaked due to enhanced ion diffusion. The imaging technique is to be implemented soon on the NIF. This work was supported in part by NLUF, DOE, and LLE.

The time scale of quasifission process in reactions with heavy ions

NASA Astrophysics Data System (ADS)

Knyazheva, G. N.; Itkis, I. M.; Kozulin, E. M.

2014-05-01

The study of mass-energy distributions of binary fragments obtained in the reactions of 36S, 48Ca, 58Fe and 64Ni ions with the 232Th, 238U, 244Pu and 248Cm at energies below and above the Coulomb barrier is presented. These data have been measured by two time-of-flight CORSET spectrometer. The mass resolution of the spectrometer for these measurements was about 3u. It allows to investigate the features of mass distributions with good accuracy. The properties of mass and TKE of QF fragments in dependence on interaction energy have been investigated and compared with characteristics of the fusion-fission process. To describe the quasifission mass distribution the simple method has been proposed. This method is based on the driving potential of the system and time dependent mass drift. This procedure allows to estimate QF time scale from the measured mass distributions. It has been found that the QF time exponentially decreases when the reaction Coulomb factor Z1Z2 increases.

Reaction dynamics studies for the system 7Be+58Ni

NASA Astrophysics Data System (ADS)

Torresi, D.; Mazzocco, M.; Acosta, L.; Boiano, A.; Boiano, C.; Diaz-Torres, A.; Fierro, N.; Glodariu, T.; Grilj, L.; Guglielmetti, A.; Keeley, N.; La Commara, M.; Martel, I.; Mazzocchi, C.; Molini, P.; Pakou, A.; Parascandolo, C.; Parkar, V. V.; Patronis, N.; Pierroutsakou, D.; Romoli, M.; Rusek, K.; Sanchez-Benitez, A. M.; Sandoli, M.; Signorini, C.; Silvestri, R.; Soramel, F.; Stiliaris, E.; Strano, E.; Stroe, L.; Zerva, K.

2015-04-01

The study of reactions induced by exotic weakly bound nuclei at energies around the Coulomb barrier had attracted a large interest in the last decade, since the features of these nuclei can deeply affect the reaction dynamics. The discrimination between different reaction mechanisms is, in general, a rather difficult task. It can be achieved by using detector arrays covering high solid angle and with high granularity that allow to measure the reaction products and, possibly, coincidences between them, as, for example, recently done for stable weakly bound nuclei [1, 2]. We investigated the collision of the weakly bound nucleus 7Be on a 58Ni target at the beam energy of 1.1 times the Coulomb barrier, measuring the elastic scattering angular distribution and the energy and angular distributions of 3He and 4He. The 7Be radioactive ion beam was produced by the facility EXOTIC at INFN-LNL with an energy of 22 MeV and an intensity of ~3×105 pps. Results showed that the 4He yeld is about 4 times larger than 3He yield, suggesting that reaction mechanisms other than the break-up mostly produce the He isotopes. Theoretical calculations for transfer channels and compound nucleus reactions suggest that complete fusion accounts for (41±5%) of the total reaction cross section extracted from optical model analysis of the elastic scattering data, and that 3He and 4He stripping are the most populated reaction channels among direct processes. Eventually estimation of incomplete fusion contributions to the 3,4He production cross sections was performed through semi-classical calculations with the code PLATYPUS [3].

Mass spectra and fusion cross sections for /sup 20/Ne+/sup 24/Mg interaction at 55 and 85 MeV

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grotowski, K.; Belery, P.; Delbar, T.

1981-06-01

Inclusive ..gamma.. spectra from the /sup 20/Ne+/sup 24/Mg interaction have been measured using 55- and 85-MeV /sup 20/Ne ions. The identification of ..gamma.. lines allows the determination of mass spectra in the region 12< or =A< or =43. Experimental results are compared with statistical model calculations. The total reaction and fusion cross sections are extracted. Cross sections for inelastic scattering, few nucleon transfers, and deep inelastic scattering are estimated.

Progress Towards the Development of a Traveling Wave Direct Energy Converter for Aneutronic Fusion Propulsion Applications

NASA Technical Reports Server (NTRS)

Tarditi, A. G.; Chap, A.; Wolinsky, J.; Scott, J. H.

2015-01-01

A coordinated experimental and theory/simulation effort has been carried out to investigate the physics of the Traveling Wave Direct Energy Converter (TWDEC), a scheme that has been proposed in the past for the direct conversion into electricity of the kinetic energy of an ion beam generated from fusion reactions. This effort has been focused in particular on the TWDEC process in the high density beam regime, thus accounting for the ion beam expansion due to its space charge.

ABC effect and resonance d*(2380)

NASA Astrophysics Data System (ADS)

Bashkanov, M.; Clement, H.; Doroshkevich, E.; Skorodko, T.

2017-11-01

A new state in the two-baryon system with mass 2380 MeV and width 80 MeV has been detected in the experiments at the Juelich Cooler Synchrotron (COSY). The new particle denoted now d*(2380) has quantum numbers I( J p ) = 0(3+). The total cross sections for the d and 4He fusion reactions show similar to each other resonance-like energy dependence. The resonance-like structure is sensed in the double-pionic fusion channels and polarized np scattering.

PHYSICS: Will Livermore Laser Ever Burn Brightly?

PubMed

Seife, C; Malakoff, D

2000-08-18

The National Ignition Facility (NIF), a superlaser being built here at Lawrence Livermore National Laboratory in an effort to use lasers rather than nuclear explosions to create a fusion reaction, is supposed to allow weapons makers to preserve the nuclear arsenal--and do nifty fusion science, too. But a new report that examines its troubled past also casts doubt on its future. Even some of NIF's scientific and political allies are beginning to talk openly of a scaled-down version of the original 192-laser design.

Graphite for the nuclear industry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burchell, T.D.; Fuller, E.L.; Romanoski, G.R.

Graphite finds applications in both fission and fusion reactors. Fission reactors harness the energy liberated when heavy elements, such as uranium or plutonium, fragment or fission''. Reactors of this type have existed for nearly 50 years. The first nuclear fission reactor, Chicago Pile No. 1, was constructed of graphite under a football stand at Stagg Field, University of Chicago. Fusion energy devices will produce power by utilizing the energy produced when isotopes of the element hydrogen are fused together to form helium, the same reaction that powers our sun. The role of graphite is very different in these two reactormore » systems. Here we summarize the function of the graphite in fission and fusion reactors, detailing the reasons for their selection and discussing some of the challenges associated with their application in nuclear fission and fusion reactors. 10 refs., 15 figs., 1 tab.« less

Arrest of trans-SNARE zippering uncovers loosely and tightly docked intermediates in membrane fusion.

PubMed

Yavuz, Halenur; Kattan, Iman; Hernandez, Javier Matias; Hofnagel, Oliver; Witkowska, Agata; Raunser, Stefan; Walla, Peter Jomo; Jahn, Reinhard

2018-04-17

Soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins mediate intracellular membrane fusion in the secretory pathway. They contain conserved regions, termed SNARE motifs, that assemble between opposing membranes directionally from their N-termini to their membrane-proximal C-termini in a highly exergonic reaction. However, how this energy is utilized to overcome the energy barriers along the fusion pathway is still under debate. Here we have used mutants of the SNARE synaptobrevin to arrest trans-SNARE zippering at defined stages. We have uncovered two distinct vesicle docking intermediates, where the membranes are loosely and tightly connected, respectively. The tightly connected state is irreversible and independent of maintaining assembled SNARE complexes. Together, our results shed new light on the intermediate stages along the pathway of membrane fusion. Published under license by The American Society for Biochemistry and Molecular Biology, Inc.

Realizing "2001: A Space Odyssey": Piloted Spherical Torus Nuclear Fusion Propulsion

NASA Technical Reports Server (NTRS)

Williams, Craig H.; Dudzinski, Leonard A.; Borowski, Stanley K.; Juhasz, Albert J.

2005-01-01

A conceptual vehicle design enabling fast, piloted outer solar system travel was created predicated on a small aspect ratio spherical torus nuclear fusion reactor. The initial requirements were satisfied by the vehicle concept, which could deliver a 172 mt crew payload from Earth to Jupiter rendezvous in 118 days, with an initial mass in low Earth orbit of 1,690 mt. Engineering conceptual design, analysis, and assessment was performed on all major systems including artificial gravity payload, central truss, nuclear fusion reactor, power conversion, magnetic nozzle, fast wave plasma heating, tankage, fuel pellet injector, startup/re-start fission reactor and battery bank, refrigeration, reaction control, communications, mission design, and space operations. Detailed fusion reactor design included analysis of plasma characteristics, power balance/utilization, first wall, toroidal field coils, heat transfer, and neutron/x-ray radiation. Technical comparisons are made between the vehicle concept and the interplanetary spacecraft depicted in the motion picture 2001: A Space Odyssey.

Impact of fluorescent protein fusions on the bacterial flagellar motor.

PubMed

Heo, M; Nord, A L; Chamousset, D; van Rijn, E; Beaumont, H J E; Pedaci, F

2017-10-03

Fluorescent fusion proteins open a direct and unique window onto protein function. However, they also introduce the risk of perturbation of the function of the native protein. Successful applications of fluorescent fusions therefore rely on a careful assessment and minimization of the side effects, but such insight is still lacking for many applications. This is particularly relevant in the study of the internal dynamics of motor proteins, where both the chemical and mechanical reaction coordinates can be affected. Fluorescent proteins fused to the stator of the Bacterial Flagellar Motor (BFM) have previously been used to unveil the motor subunit dynamics. Here we report the effects on single motors of three fluorescent proteins fused to the stators, all of which altered BFM behavior. The torque generated by individual stators was reduced while their stoichiometry remained unaffected. MotB fusions decreased the switching frequency and induced a novel bias-dependent asymmetry in the speed in the two directions. These effects could be mitigated by inserting a linker at the fusion point. These findings provide a quantitative account of the effects of fluorescent fusions to the stator on BFM dynamics and their alleviation- new insights that advance the use of fluorescent fusions to probe the dynamics of protein complexes.

The Rab3A-22A Chimera Prevents Sperm Exocytosis by Stabilizing Open Fusion Pores.

PubMed

Quevedo, María F; Lucchesi, Ornella; Bustos, Matías A; Pocognoni, Cristian A; De la Iglesia, Paola X; Tomes, Claudia N

2016-10-28

At the final stage of exocytotis, a fusion pore opens between the plasma and a secretory vesicle membranes; typically, when the pore dilates the vesicle releases its cargo. Sperm contain a large dense-core secretory granule (the acrosome) whose contents are secreted by regulated exocytosis at fertilization. Minutes after the arrival of the triggering signal, the acrosomal and plasma membranes dock at multiple sites and fusion pores open at the contact points. It is believed that immediately afterward, fusion pores dilate spontaneously. Rab3A is an essential component of human sperm exocytotic machinery. Yet, recombinant, persistently active Rab3A halts calcium-triggered secretion when introduced after docking into streptolysin O-permeabilized cells; so does a Rab3A-22A chimera. Here, we applied functional assays, electron and confocal microscopy to show that the secretion blockage is due to the stabilization of open fusion pores. Other novel findings are that sperm SNAREs engage in α-SNAP/NSF-sensitive complexes at a post-fusion stage. Complexes are disentangled by these chaperons to achieve vesiculation and acrosomal contents release. Thus, post-fusion regulation of the pores determines their expansion and the success of the acrosome reaction. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Moderator design studies for a new neutron reference source based on the D-T fusion reaction

NASA Astrophysics Data System (ADS)

Mozhayev, Andrey V.; Piper, Roman K.; Rathbone, Bruce A.; McDonald, Joseph C.

2016-06-01

The radioactive isotope Californium-252 (252Cf) is relied upon internationally as a neutron calibration source for ionizing radiation dosimetry because of its high specific activity. The source may be placed within a heavy-water (D2O) moderating sphere to produce a softened spectrum representative of neutron fields common to commercial nuclear power plant environments, among others. Due to termination of the U.S. Department of Energy loan/lease program in 2012, the expense of obtaining 252Cf sources has undergone a significant increase, rendering high output sources largely unattainable. On the other hand, the use of neutron generators in research and industry applications has increased dramatically in recent years. Neutron generators based on deuteriumtritium (D-T) fusion reaction provide high neutron fluence rates and, therefore, could possibly be used as a replacement for 252Cf. To be viable, the 14 MeV D-T output spectrum must be significantly moderated to approximate common workplace environments. This paper presents the results of an effort to select appropriate moderating materials and design a configuration to reshape the primary neutron field toward a spectrum approaching that from a nuclear power plant workplace. A series of Monte-Carlo (MCNP) simulations of single layer high- and low-Z materials are used to identify initial candidate moderators. Candidates are refined through a similar series of simulations involving combinations of 2-5 different materials. The simulated energy distribution using these candidate moderators are rated in comparison to a target spectrum. Other properties, such as fluence preservation and/or enhancement, prompt gamma production and other characteristics are also considered.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hagen, E. C.; Lowe, D. R.; O'Brien, R.

Dense Plasma Focus (DPF) machines are in use worldwide or a wide variety of applications; one of these is to produce intense, short bursts of fusion via r-Z pinch heating and compression of a working gas. We have designed and constructed a series of these, ranging from portable to a maximum energy storage capacity of 2 MJ. Fusion rates from 5 DPF pulsed fusion generators have been measured in a single laboratory using calibrated activation detectors. Measured rates range from ~ 1015 to more than 1019 fusions per second have been measured. Fusion rates from the intense short (20 –more » 50 ns) periods of production were inferred from measurement of neutron production using both calibrated activation detectors and scintillator-PMT neutron time of flight (NTOF) detectors. The NTOF detectors are arranged to measure neutrons versus time over flight paths of 30 Meters. Fusion rate scaling versus energy and current will be discussed. Data showing observed fusion cutoff at D-D fusion yield levels of approximately 1*1012, and corresponding tube currents of ~ 3 MA will be shown. Energy asymmetry of product neutrons will also be discussed. Data from the NTOF lines of sight have been used to measure energy asymmetries of the fusion neutrons. From this, center of mass energies for the D(d,n)3He reaction are inferred. A novel re-entrant chamber that allows extremely high single pulse neutron doses (> 109 neutrons/cm2 in 50 ns) to be supplied to samples will be described. Machine characteristics and detector types will be discussed.« less

Identification of Alternative Splicing and Fusion Transcripts in Non-Small Cell Lung Cancer by RNA Sequencing.

PubMed

Hong, Yoonki; Kim, Woo Jin; Bang, Chi Young; Lee, Jae Cheol; Oh, Yeon-Mok

2016-04-01

Lung cancer is the most common cause of cancer related death. Alterations in gene sequence, structure, and expression have an important role in the pathogenesis of lung cancer. Fusion genes and alternative splicing of cancer-related genes have the potential to be oncogenic. In the current study, we performed RNA-sequencing (RNA-seq) to investigate potential fusion genes and alternative splicing in non-small cell lung cancer. RNA was isolated from lung tissues obtained from 86 subjects with lung cancer. The RNA samples from lung cancer and normal tissues were processed with RNA-seq using the HiSeq 2000 system. Fusion genes were evaluated using Defuse and ChimeraScan. Candidate fusion transcripts were validated by Sanger sequencing. Alternative splicing was analyzed using multivariate analysis of transcript sequencing and validated using quantitative real time polymerase chain reaction. RNA-seq data identified oncogenic fusion genes EML4-ALK and SLC34A2-ROS1 in three of 86 normal-cancer paired samples. Nine distinct fusion transcripts were selected using DeFuse and ChimeraScan; of which, four fusion transcripts were validated by Sanger sequencing. In 33 squamous cell carcinoma, 29 tumor specific skipped exon events and six mutually exclusive exon events were identified. ITGB4 and PYCR1 were top genes that showed significant tumor specific splice variants. In conclusion, RNA-seq data identified novel potential fusion transcripts and splice variants. Further evaluation of their functional significance in the pathogenesis of lung cancer is required.

Fusion gene profile of biphenotypic sinonasal sarcoma: an analysis of 44 cases.

PubMed

Fritchie, Karen J; Jin, Long; Wang, Xiaoke; Graham, Rondell P; Torbenson, Michael S; Lewis, Jean E; Rivera, Michael; Garcia, Joaquin J; Schembri-Wismayer, David J; Westendorf, Jennifer J; Chou, Margaret M; Dong, Jie; Oliveira, Andre M

2016-12-01

Biphenotypic sinonasal sarcoma (SNS) is a locally aggressive tumour that occurs in the sinonasal region. PAX3-MAML3 has recently been identified as a recurrent fusion gene event in this entity; however, a subset of tumours harbour alternative PAX3 rearrangement without the involvement of MAML3. In this study we sought to characterize the molecular profile of a large series of cases, with a special emphasis on tumours with alternative fusions. Forty-four examples of SNS were screened by fluorescence in-situ hybridization and reverse transcription polymerase chain reaction to better characterize its molecular profile and identify potential novel fusion genes. Twenty-four were positive for PAX3-MAML3 (55%), 15 showed rearrangements of PAX3 without MAML3 involvement (34%), one showed rearrangement of MAML3 without PAX3 involvement, and four were negative for the involvement of either gene (9%). Among 15 cases with PAX3 involvement only, three were found to harbour PAX3-FOXO1. Two of these cases arose in the nasal cavities of female patients (aged 31 and 47 years), and one showed bilateral involvement of the nasal cavities of a 35-year-old male. A fourth case involved the skull base of a 47-year-old male, and was positive for PAX3-NCOA1. Patients with fusion-negative tumours were slightly older. More than half of the SNSs in this series were positive for PAX3-MAML3. However, a subset of tumours may harbour alternative PAX3 fusion genes or show no involvement of PAX3. Except for a possible weak association between age and molecular profile, the overall morphological and immunophenotypic features of all cases seem to be similar. Because of the rarity of these tumours, the impact of the molecular profile on the clinical course of these tumours remains to be determined. © 2016 John Wiley & Sons Ltd.

A Study of Primary Collision Dynamics in Inverse-Kinematics Reaction of 78Kr on 40Ca at a Bombarding Energy of 10 MeV per Nucleon

NASA Astrophysics Data System (ADS)

Henry, Eric M.

The CHIMERA multi-detector array at LNS Catania has been used to study the inverse-kinematics reaction of 78Kr + 40Ca at a bombarding energy of 10 A MeV. The multi-detector is capable of detecting individual products of the collision essential for the reconstruction of the collision dynamics. This is the first time CHIMERA has been used at low-energy, which offered a unique challenge for the calibration and interpretation of experimental data. Initial interrogation of the calibrated data revealed a class of selected events characterized by two coincident heavy fragments (atomic number Z>3) that together account for the majority of the total mass of the colliding system. These events are consistent with the complete fusion and subsequent binary split (fission) of a composite nucleus. The observed fission fragments are characterized by a broad A, Z distribution and are centered about symmetric fission while exhibiting relative velocities significantly higher than given by Viola systematics. Additional analysis of the kinematic relationship between the fission fragments was performed. Of note, is that the center-of-mass angular distribution (dsigma/dtheta) of the fission fragments exhibits an unexpected anisotropy inconsistent with a compound-nucleus reaction. This anisotropy is indicative of a dynamic fusion/fission-like process. The observed angular distribution features a forward-backward anisotropy most prevalent for mass-asymmetric events. Furthermore, the more massive fragment of mass-asymmetric events appears to emerge preferentially in the forward direction, along the beam axis. Analysis of the angular distribution of alpha particles emitted from these fission fragments suggests the events are associated mostly with central collisions. The observations associated with this subset of events are similar to those reported for dynamic fragmentation of projectile-like fragments, but have not before been observed for a fusion/fission-like process. Comparisons to dynamic and statistical reaction model predictions are inconsistent with known phenomena, but suggest a peculiar dynamics-driven scenario. A plausible explanation of the experimental results is the existence of a phenomenon similar to a "fusion window", or a range of impact parameters in which complete fusion cannot be achieved. In this scenario, the system must absorb all the relative motion and convert it to vibrational energy or heat. As the energy increases the system may not be able to accommodate this conversion of energy without breaking apart.

Membrane events in the acrosomal reaction of Limulus sperm. Membrane fusion, filament-membrane particle attachment, and the source and formation of new membrane surface

PubMed Central

1979-01-01

The membranes of Limulus (horseshoe crab) sperm were examined before and during the acrosomal reaction by using the technique of freeze- fracturing and thin sectioning. We focused on three areas. First, we examined stages in the fusion of the acrosomal vacuole with the cell surface. Fusion takes place in a particle-free zone which is surrounded by a circlet of particles on the P face of the plasma membrane and an underlying circlet of particles on the P face of the acrosomal vauole membrane. These circlets of particles are present before induction. Up to nine focal points of fusion occur within the particle-free zone. Second, we describe a system of fine filaments, each 30 A in diameter, which lies between the acrosomal vacuole and the plasma membrane. These filaments change their orientation as the vacuole opens, a process that takes place in less than 50 ms. Membrane particles seen on the P face of the acrosomal vacuole membrane change their orientation at the same time and in the same way as do the filaments, thus indicating that the membrane particles and filaments are probably connected. Third, we examined the source and the point of fusion of new membrane needed to cover the acrosomal process. This new membrane is almost certainly derived from the outer nuclear envelope and appears to insert into the plasma membrane in a particle-free area adjacent to an area rich in particles. The latter is the region where the particles are probably connected to the cytoplasmic filaments. The relevance of these observations in relation to the process of fertilization of this fantastic sperm is discussed. PMID:582596

Binaural Fusion and Listening Effort in Children Who Use Bilateral Cochlear Implants: A Psychoacoustic and Pupillometric Study

PubMed Central

Steel, Morrison M.; Papsin, Blake C.; Gordon, Karen A.

2015-01-01

Bilateral cochlear implants aim to provide hearing to both ears for children who are deaf and promote binaural/spatial hearing. Benefits are limited by mismatched devices and unilaterally-driven development which could compromise the normal integration of left and right ear input. We thus asked whether children hear a fused image (ie. 1 vs 2 sounds) from their bilateral implants and if this “binaural fusion” reduces listening effort. Binaural fusion was assessed by asking 25 deaf children with cochlear implants and 24 peers with normal hearing whether they heard one or two sounds when listening to bilaterally presented acoustic click-trains/electric pulses (250 Hz trains of 36 ms presented at 1 Hz). Reaction times and pupillary changes were recorded simultaneously to measure listening effort. Bilaterally implanted children heard one image of bilateral input less frequently than normal hearing peers, particularly when intensity levels on each side were balanced. Binaural fusion declined as brainstem asymmetries increased and age at implantation decreased. Children implanted later had access to acoustic input prior to implantation due to progressive deterioration of hearing. Increases in both pupil diameter and reaction time occurred as perception of binaural fusion decreased. Results indicate that, without binaural level cues, children have difficulty fusing input from their bilateral implants to perceive one sound which costs them increased listening effort. Brainstem asymmetries exacerbate this issue. By contrast, later implantation, reflecting longer access to bilateral acoustic hearing, may have supported development of auditory pathways underlying binaural fusion. Improved integration of bilateral cochlear implant signals for children is required to improve their binaural hearing. PMID:25668423

Performance characteristics of a reverse transcriptase-polymerase chain reaction assay for the detection of tumor-specific fusion transcripts from archival tissue.

PubMed

Fritsch, Michael K; Bridge, Julia A; Schuster, Amy E; Perlman, Elizabeth J; Argani, Pedram

2003-01-01

Pediatric small round cell tumors still pose tremendous diagnostic problems. In difficult cases, the ability to detect tumor-specific gene fusion transcripts for several of these neoplasms, including Ewing sarcoma/peripheral primitive neuroectodermal tumor (ES/PNET), synovial sarcoma (SS), alveolar rhabdomyosarcoma (ARMS), and desmoplastic small round cell tumor (DSRCT) using reverse transcriptase-polymerase chain reaction (RT-PCR), can be extremely helpful. Few studies to date, however, have systematically examined several different tumor types for the presence of multiple different fusion transcripts in order to determine the specificity and sensitivity of the RT-PCR method, and no study has addressed this issue for formalin-fixed material. The objectives of this study were to address the specificity, sensitivity, and practicality of such an assay applied strictly to formalin-fixed tissue blocks. Our results demonstrate that, for these tumors, the overall sensitivity for detecting each fusion transcript is similar to that reported in the literature for RT-PCR on fresh or formalin-fixed tissues. The specificity of the assay is very high, being essentially 100% for each primer pair when interpreting the results from visual inspection of agarose gels. However, when these same agarose gels were examined using Southern blotting, a small number of tumors also yielded reproducibly detectable weak signals for unexpected fusion products, in addition to a strong signal for the expected fusion product. Fluorescence in situ hybridization (FISH) studies in one such case indicated that a rearrangement that would account for the unexpected fusion was not present, while another case was equivocal. The overall specificity for each primer pair used in this assay ranged from 94 to 100%. Therefore, RT-PCR using formalin-fixed paraffin-embedded tissue sections can be used to detect chimeric transcripts as a reliable, highly sensitive, and highly specific diagnostic assay. However, we strongly suggest that the final interpretation of the results from this assay be viewed in light of the other features of the case, including clinical history, histology, and immunohistochemistry, by the diagnostic pathologist. Additional studies such as FISH may be useful in clarifying the nature of equivocal or unexpected results.

Simulation of Charge Collection in Diamond Detectors Irradiated with Deuteron-Triton Neutron Sources

DOE Office of Scientific and Technical Information (OSTI.GOV)

Milocco, Alberto; Trkov, Andrej; Pillon, Mario

2011-12-13

Diamond-based neutron spectrometers exhibit outstanding properties such as radiation hardness, low sensitivity to gamma rays, fast response and high-energy resolution. They represent a very promising application of diamonds for plasma diagnostics in fusion devices. The measured pulse height spectrum is obtained from the collection of helium and beryllium ions produced by the reactions on {sup 12}C. An original code is developed to simulate the production and the transport of charged particles inside the diamond detector. The ion transport methodology is based on the well-known TRIM code. The reactions of interest are triggered using the ENDF/B-VII.0 nuclear data for the neutronmore » interactions on carbon. The model is implemented in the TALLYX subroutine of the MCNP5 and MCNPX codes. Measurements with diamond detectors in a {approx}14 MeV neutron field have been performed at the FNG (Rome, Italy) and IRMM (Geel, Belgium) facilities. The comparison of the experimental data with the simulations validates the proposed model.« less

Homeland security application of the Army Soft Target Exploitation and Fusion (STEF) system

NASA Astrophysics Data System (ADS)

Antony, Richard T.; Karakowski, Joseph A.

2010-04-01

A fusion system that accommodates both text-based extracted information along with more conventional sensor-derived input has been developed and demonstrated in a terrorist attack scenario as part of the Empire Challenge (EC) 09 Exercise. Although the fusion system was developed to support Army military analysts, the system, based on a set of foundational fusion principles, has direct applicability to department of homeland security (DHS) & defense, law enforcement, and other applications. Several novel fusion technologies and applications were demonstrated in EC09. One such technology is location normalization that accommodates both fuzzy semantic expressions such as behind Library A, across the street from the market place, as well as traditional spatial representations. Additionally, the fusion system provides a range of fusion products not supported by traditional fusion algorithms. Many of these additional capabilities have direct applicability to DHS. A formal test of the fusion system was performed during the EC09 exercise. The system demonstrated that it was able to (1) automatically form tracks, (2) help analysts visualize behavior of individuals over time, (3) link key individuals based on both explicit message-based information as well as discovered (fusion-derived) implicit relationships, and (4) suggest possible individuals of interest based on their association with High Value Individuals (HVI) and user-defined key locations.

Nuclear diagnostic for fast alpha particles

DOEpatents

Grisham, L.R.; Post, D.E. Jr.; Dawson, J.M.

1983-11-23

This invention relates generally to high energy confined plasmas and more particularly is directed to measuring the velocity distribution of confined energetic alpha particles resulting from deuterium-tritium fusion reactions in a confined energetic plasma.