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Sample records for fusion reaction products

  1. Transfer-type products accompanying cold fusion reactions

    SciTech Connect

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

    2005-12-15

    Production of nuclei heavier than the target is treated for projectile-target combinations used in cold fusion reactions leading to superheavy nuclei. These products are related to transfer-type or to asymmetry-exit-channel quasifission reactions. The production of isotopes in the transfer-type reactions emitting of {alpha} particles with large energies is discussed.

  2. Measuring time of flight of fusion products in an inertial electrostatic confinement fusion device for spatial profiling of fusion reactions

    NASA Astrophysics Data System (ADS)

    Donovan, D. C.; Boris, D. R.; Kulcinski, G. L.; Santarius, J. F.; Piefer, G. R.

    2013-03-01

    A new diagnostic has been developed that uses the time of flight (TOF) of the products from a nuclear fusion reaction to determine the location where the fusion reaction occurred. The TOF diagnostic uses charged particle detectors on opposing sides of the inertial electrostatic confinement (IEC) device that are coupled to high resolution timing electronics to measure the spatial profile of fusion reactions occurring between the two charged particle detectors. This diagnostic was constructed and tested by the University of Wisconsin-Madison Inertial Electrostatic Confinement Fusion Group in the IEC device, HOMER, which accelerates deuterium ions to fusion relevant energies in a high voltage (˜100 kV), spherically symmetric, electrostatic potential well [J. F. Santarius, G. L. Kulcinski, R. P. Ashley, D. R. Boris, B. B. Cipiti, S. K. Murali, G. R. Piefer, R. F. Radel, T. E. Radel, and A. L. Wehmeyer, Fusion Sci. Technol. 47, 1238 (2005)]. The TOF diagnostic detects the products of D(d,p)T reactions and determines where along a chord through the device the fusion event occurred. The diagnostic is also capable of using charged particle spectroscopy to determine the Doppler shift imparted to the fusion products by the center of mass energy of the fusion reactants. The TOF diagnostic is thus able to collect spatial profiles of the fusion reaction density along a chord through the device, coupled with the center of mass energy of the reactions occurring at each location. This provides levels of diagnostic detail never before achieved on an IEC device.

  3. Measuring time of flight of fusion products in an inertial electrostatic confinement fusion device for spatial profiling of fusion reactions

    SciTech Connect

    Donovan, D. C.; Boris, D. R.; Kulcinski, G. L.; Santarius, J. F.; Piefer, G. R.

    2013-03-15

    A new diagnostic has been developed that uses the time of flight (TOF) of the products from a nuclear fusion reaction to determine the location where the fusion reaction occurred. The TOF diagnostic uses charged particle detectors on opposing sides of the inertial electrostatic confinement (IEC) device that are coupled to high resolution timing electronics to measure the spatial profile of fusion reactions occurring between the two charged particle detectors. This diagnostic was constructed and tested by the University of Wisconsin-Madison Inertial Electrostatic Confinement Fusion Group in the IEC device, HOMER, which accelerates deuterium ions to fusion relevant energies in a high voltage ({approx}100 kV), spherically symmetric, electrostatic potential well [J. F. Santarius, G. L. Kulcinski, R. P. Ashley, D. R. Boris, B. B. Cipiti, S. K. Murali, G. R. Piefer, R. F. Radel, T. E. Radel, and A. L. Wehmeyer, Fusion Sci. Technol. 47, 1238 (2005)]. The TOF diagnostic detects the products of D(d,p)T reactions and determines where along a chord through the device the fusion event occurred. The diagnostic is also capable of using charged particle spectroscopy to determine the Doppler shift imparted to the fusion products by the center of mass energy of the fusion reactants. The TOF diagnostic is thus able to collect spatial profiles of the fusion reaction density along a chord through the device, coupled with the center of mass energy of the reactions occurring at each location. This provides levels of diagnostic detail never before achieved on an IEC device.

  4. Production of exotic isotopes in complete fusion reactions with radioactive beams

    NASA Astrophysics Data System (ADS)

    Sargsyan, V. V.; Zubov, A. S.; Adamian, G. G.; Antonenko, N. V.; Heinz, S.

    2013-11-01

    The isotopic dependence of the complete fusion (capture) cross section is analyzed in the reactions 130,132,134,136,138,140,142,144,146,148,150Xe+48Ca with stable and radioactive beams. It is shown for the first time that the very neutron-rich nuclei 186-191W can be reached with relatively large cross sections by complete fusion reactions with radioactive ion beams at incident energies near the Coulomb barrier. A comparison between the complete fusion and fragmentation reactions for the production of neutron-rich W and neutron-deficient Rn isotopes is performed.

  5. Production of heavy actinides in incomplete fusion reactions

    NASA Astrophysics Data System (ADS)

    Antonenko, N. V.; Cherepanov, E. A.; Iljinov, A. S.; Mebel, M. V.

    1994-10-01

    We present preliminary results of calculations by the phenomenological model of the estimated yield of some heavy actinide isotopes. It is assumed that these isotopes are produced as a result of multinucleon transfers followed by neutrons and charged particle emission A.S. Iljinov and E.A. Cherepanov (1980). The yield P(sub Z, N)(E*) of primary excited actinides is found using the model of N.V. Antonenko and R.V. Jolos (1991). Absolute cross-sections for different binary reaction channels are obtained by summing the cross-sections for all subchannels with an appreciable yield according to J. Wilczynski et al. (1980).

  6. Expected production of new exotic α emitters 108Xe and 112Ba in complete fusion reactions

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

    The production cross sections of neutron-deficient isotopes Xe-110108 and Ba-114112 in the complete fusion reactions Ni,5658+54Fe and Ni,5658+58Ni with stable and radioactive beams are studied with the dinuclear system model. The calculated results are compared with the available experimental data. The optimal beam energies and corresponding maximum production cross sections of new isotopes 108Xe and 112Ba are predicted.

  7. Role of angular momentum in the production of complex fragments in fusion and quasifission reactions

    SciTech Connect

    Kalandarov, Sh. A.; Adamian, G. G.; Antonenko, N. V.; Scheid, W.

    2011-05-15

    The influence of angular momentum on the competition between complete fusion followed by the decay of compound nucleus and quasifission channels is treated within the dinuclear system model. The charge distributions of the products in the reactions {sup 28}Si+{sup 96}Zr, {sup 4}He+{sup 130}Te, and {sup 40}Ca+{sup 82}Kr are predicted at bombarding energies above the Coulomb barrier. The results of calculations for the reactions {sup 93}Nb+{sup 9}Be,{sup 12}C,{sup 27}Al; {sup 84}Kr+{sup 27}Al; {sup 86}Kr+{sup 63}Cu; {sup 139}La+{sup 12}C,{sup 27}Al; and {sup 45}Sc+{sup 65}Cu are compared with the available experimental data.

  8. 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.

  9. 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.

  10. Production of the doubly magic nucleus Sn100 in fusion and quasifission reactions via light particle and cluster emission channels

    NASA Astrophysics Data System (ADS)

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

    2014-08-01

    The possibilities of production of the doubly magic nucleus Sn100 in complete fusion and quasifission reactions with stable and radioactive ion beams are investigated within a dinuclear system model. The excitation functions for production of the exotic nuclei 100-103Sn and 112,114Ba via xn, pxn, αxn, and 12,14Cxn emission channels are predicted for future experiments.

  11. Product PCNPsurv or the "reduced" evaporation residue cross section σER/σfusion for "hot" fusion reactions studied with the dynamical cluster-decay model

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

    The product PCNPsurv of compound nucleus (CN) fusion probability PCN and survival probability Psurv is calculated to determine the reduced evaporation residue cross section σER/σfusion , denoted σERreduced, with (total) fusion cross section σfusion given as a sum of CN-formation cross section σCN and non-CN cross section σnCN for each reaction, where σCN is the sum of evaporation residue cross section σER and fusion-fission cross section σff and σnCN, if not measured, is estimated empirically as the difference between measured and calculated σfusion. Our calculations of PCN and Psurv, based on the dynamical cluster-decay model, were successfully made for some 17 "hot" fusion reactions, forming different CN of mass numbers ACN˜100 -300 , with deformations of nuclei up to hexadecapole deformations and "compact" orientations for both coplanar (Φc=0∘ ) and noncoplanar (Φc≠0∘ ) configurations, using various different nuclear interaction potentials. Interesting variations of σERreduced with CN excitation energy E*, fissility parameter χ , CN mass ACN, and Coulomb parameter Z1Z2 show that, independent of entrance channel, different isotopes of CN, and nuclear interaction potentials used, the dominant quantity in the product is Psurv, which classifies all the studied CN into three groups of weakly fissioning, radioactive, and strongly fissioning superheavy nuclei, with relative magnitudes of σERreduced˜1 , ˜10-6 , and ˜10-11 , which, like for PCN, get further grouped in two dependencies of (i) weakly fissioning and strongly fissioning superheavy nuclei decreasing with increasing E* and (ii) radioactive nuclei increasing with increasing E*.

  12. Possibilities of production of neutron-deficient isotopes of U, Np, Pu, Am, Cm, and Cf in complete fusion reactions

    SciTech Connect

    Adamian, G. G.; Antonenko, N. V.; Zubov, A. S.; Scheid, W.

    2008-10-15

    Within the dinuclear system model we analyze the production of yet unknown neutron-deficient isotopes of U, Np, Pu, Am, Cm, and Cf in various complete fusion reactions. Different deexcitation channels of the excited compound nucleus are treated. The results are obtained without special adjustment to the selected evaporation channel. The fusion probability is an important ingredient of the excitation function. The results are in good agreement with the available experimental data. The alpha decay half-life times in the neutron-deficient actinides are discussed.

  13. PRODUCTION OF {sup 9}Be THROUGH THE {alpha}-FUSION REACTION OF METAL-POOR COSMIC RAYS AND STELLAR FLARES

    SciTech Connect

    Kusakabe, Motohiko; Kawasaki, Masahiro E-mail: kawasaki@icrr.u-tokyo.ac.jp

    2013-04-10

    Spectroscopic observations of metal-poor stars have indicated possible {sup 6}Li abundances that are much larger than the primordial abundance predicted in the standard big bang nucleosynthesis model. Possible mechanisms of {sup 6}Li production in metal-poor stars include pregalactic and cosmological cosmic-ray (CR) nucleosynthesis and nucleosynthesis by flare-accelerated nuclides. We study {sup 9}Be production via two-step {alpha}-fusion reactions of CR or flare-accelerated {sup 3,4}He through {sup 6}He and {sup 6,7}Li, in pregalactic structure, intergalactic medium, and stellar surfaces. We solve transfer equations of CR or flare particles and calculate nuclear yields of {sup 6}He, {sup 6,7}Li, and {sup 9}Be taking account of probabilities of processing {sup 6}He and {sup 6,7}Li into {sup 9}Be via fusions with {alpha} particles. Yield ratios, i.e., {sup 9}Be/{sup 6}Li, are then calculated for the CR and flare nucleosynthesis models. We suggest that the future observations of {sup 9}Be in metal-poor stars may find enhanced abundances originating from metal-poor CR or flare activities.

  14. LINE: a code which simulates spectral line shapes for fusion reaction products generated by various speed distributions

    SciTech Connect

    Slaughter, D.

    1985-03-01

    A computer code is described which estimates the energy spectrum or ''line-shape'' for the charged particles and ..gamma..-rays produced by the fusion of low-z ions in a hot plasma. The simulation has several ''built-in'' ion velocity distributions characteristic of heated plasmas and it also accepts arbitrary speed and angular distributions although they must all be symmetric about the z-axis. An energy spectrum of one of the reaction products (ion, neutron, or ..gamma..-ray) is calculated at one angle with respect to the symmetry axis. The results are shown in tabular form, they are plotted graphically, and the moments of the spectrum to order ten are calculated both with respect to the origin and with respect to the mean.

  15. Dinuclear systems in complete fusion reactions

    NASA Astrophysics Data System (ADS)

    Adamian, G. G.; Antonenko, N. V.; Zubov, A. S.

    2014-09-01

    Formation and evolution of dinuclear systems in reactions of complete fusion are considered. Based on the dinuclear system concept, the process of compound nucleus formation is studied. Arguments confirming the validity of this concept are given. The main problems of describing the complete fusion in adiabatic approximation are listed. Calculations of evaporation residue cross sections in complete fusion reactions leading to formation of superheavy nuclei are shown. Isotopic trends of the cross sections of heavy nuclei formation in complete fusion reactions are considered.

  16. Competing fusion and quasifission reaction mechanisms in the production of superheavy nuclei

    SciTech Connect

    Huang Minghui; Gan Zaiguo; Zhou Xiaohong; Li Junqing; Scheid, W.

    2010-10-15

    Within the framework of a dinuclear system model, a new master equation is constructed and solved, which includes the relative distance of nuclei as a new dynamical variable in addition to the mass asymmetry variable so that the nucleon transfer, which leads to fusion and the evolution of the relative distance, which leads to quasifission (QF) are treated simultaneously in a consistent way. The QF mass yields and evaporation residual cross sections to produce superheavy nuclei are systematically investigated under this framework. The results fit the experimental data well. It is shown that the Kramers formula gives results of QF, which agree with those by our diffusion treatment, only if the QF barrier is high enough. Otherwise some large discrepancies occur.

  17. Fusion and reactions of exotic nuclei

    NASA Astrophysics Data System (ADS)

    Martel, I.; Aguilera, E. F.; Acosta, L.; Sánchez-Benítez, A. M.; Wolski, R.

    2011-10-01

    Close to the drip lines, the scattering cross sections of halo nuclei show a different behaviour as compared to the tightly bound projectiles of the stability line. Several experiments carried out in the last decade have been dedicated to investigate the competition between transfer, breakup and fusion channels at energies around and below the Coulomb barrier. The rather complex scenario gives rise to conflicting conclusions concerning the effect of breakup and transfer on reaction dynamics and the sub-barrier fusion process. In this work we discuss recent experimental findings in fusion and reactions of 6He halo nucleus at energies around the Coulomb barrier.

  18. Production of radon and thorium isotopes near N=126 shell closure in 48Ca and 54Cr induced fusion reactions on 162Dy

    NASA Astrophysics Data System (ADS)

    Mayorov, Dmitriy; Werke, Tyler; Alfonso, Marisa; Folden, Charles

    2012-03-01

    Production of spherical evaporation residues (EVRs) near N=126 shell in 48Ca and 54Cr induced reactions on a 162Dy target was investigated at the Texas A&M University Cyclotron Institute using the vacuum separator MARS. For the 54Cr+162Dy reaction, only upper limits for the 4n exit-channel cross section were measured; this can be attributed to a sizably increased fissility of the 216Th compound nucleus relative to 210Rn formed in the 48Ca bombardment. A factor of > 7300 separates the production cross sections of the 4n EVRs from each reaction. A semi-empirical estimate of the lower limit on the fusion probability, PCN, ratio between the two heavy ion projectiles is PCN(48Ca+162Dy)/PCN(54Cr+162Dy) > 1.2. Investigation of spherical nuclei produced by heavy ion fusion reactions is of current interest due to efforts to synthesize superheavy nuclei near Z=120, N=184 nucleon shells. EVRs produced near the N=126 shell closure have previously revealed surprisingly low survival probabilities despite stabilization from shell effects. Similarly, enhancement of the fission channel in the de-excitation cascade of 210Rn and 216Th is observed in this work and this result can be well modeled by the inclusion of collective effects into the statistical decay of excited nuclei calculations. These results suggest that cross sections for production of superheavy nuclei near predicted Z=120, N=184 closed shells may be small regardless of the anticipated strong shell effects.

  19. Formation of superheavy nuclei in cold fusion reactions

    SciTech Connect

    Feng Zhaoqing; Jin Genming; Li Junqing; Scheid, Werner

    2007-10-15

    Within the concept of the dinuclear system (DNS), a dynamical model is proposed for describing the formation of superheavy nuclei in complete fusion reactions by incorporating the coupling of the relative motion to the nucleon transfer process. The capture of two heavy colliding nuclei, the formation of the compound nucleus, and the de-excitation process are calculated by using an empirical coupled channel model, solving a master equation numerically and applying statistical theory, respectively. Evaporation residue excitation functions in cold fusion reactions are investigated systematically and compared with available experimental data. Maximal production cross sections of superheavy nuclei in cold fusion reactions with stable neutron-rich projectiles are obtained. Isotopic trends in the production of the superheavy elements Z=110, 112, 114, 116, 118, and 120 are analyzed systematically. Optimal combinations and the corresponding excitation energies are proposed.

  20. Observation of incomplete fusion reactions at l < l {sub crit}

    SciTech Connect

    Yadav, Abhishek Sharma, Vijay R. Singh, Devendra P. Unnati,; Singh, B. P.; Prasad, R.; Singh, Pushpendra P.; Bala, Indu; Kumar, R.; Muralithar, S.; Singh, R. P.; Sharma, M. K.

    2014-08-14

    In order to understand the presence of incomplete fusion at low energies i.e. 4-7MeV/nucleon and also to study its dependence on various entrance-channel parameters, the two type of measurements (i) excitation function for {sup 12}C+{sup 159}Tb, and (ii) forward recoil ranges for {sup 12}C+{sup 159}Tb systems have been performed. The experimentally measured excitation functions have been analyzed within the framework of compound nucleus decay using statistical model code PACE4. Analysis of data suggests the production of xn/px)n-channels via complete fusion, as these are found to be well reproduced by PACE4 predictions, while, a significant enhancement in the excitation functions of α-emitting channels has been observed over the theoretical ones, which has been attributed due to the incomplete fusion processes. Further, the incomplete fusion events observed in case of forward recoil range measurements have been explained on the basis of the breakup fusion model, where these events may be attributed to the fusion of {sup 8}Be and/or {sup 4}He from {sup 12}C projectile to the target nucleus. In the present work, the SUMRULE model calculations are found to highly underestimate the observed incomplete fusion cross-sections which indicate that the l-values lower than l {sub crit} (limit of complete fusion) significantly contribute to the incomplete fusion reactions.

  1. Fusion Reaction Rate in an Inhomogeneous Plasma

    SciTech Connect

    S. Son; N.J. Fisch

    2004-09-03

    The local fusion rate, obtained from the assumption that the distribution is a local Maxwellian, is inaccurate if mean-free-paths of fusing particles are not sufficiently small compared with the inhomogeneity length of the plasma. We calculate the first order correction of P0 in terms of the small spatial gradient and obtain a non-local modification of P(sub)0 in a shock region when the gradient is not small. Use is made of the fact that the fusion reaction cross section has a relatively sharp peak as a function of energy.

  2. Analysis of quasifission competition in fusion reactions forming heavy nuclei

    NASA Astrophysics Data System (ADS)

    Hammerton, Kalee; Kohley, Zachary; Morrissey, Dave; Wakhle, Aditya; Stiefel, Krystin; Hinde, David; Dasgupta, Mahananda; Williams, Elizabeth; Simenel, Cedric; Carter, Ian; Cook, Kaitlin; Jeung, Dongyun; Luong, Duc Huy; McNeil, Steven; Palshetkar, Chandani; Rafferty, Dominic

    2015-10-01

    Heavy-ion fusion reactions have provided a mechanism for the production of superheavy elements allowing for the extension of both the periodic table and chart of the nuclides. However, fusion of the projectile and target, forming a compound nucleus, is hindered by orders of magnitude by the quasifission process in heavy systems. In order to fully understand this mechanism, and make accurate predictions for superheavy element production cross sections, a clear description of the interplay between the fusion-fission and quasifission reaction channels is necessary. The mass-angle distributions of fragments formed in 8 different Cr + W reactions were measured at the Australia National University in order to explore the N/Z dependence of the quasifission process. Two sets of data were measured: one at a constant energy relative to the fusion barrier and one at a constant compound nucleus excitation energy. The results of this analysis will provide insight into the effect of using more neutron-rich beams in superheavy element production reactions.

  3. From Nucleons To Nuclei To Fusion Reactions

    SciTech Connect

    Quaglioni, S; Navratil, P; Roth, R; Horiuchi, W

    2012-02-15

    Nuclei are prototypes of many-body open quantum systems. Complex aggregates of protons and neutrons that interact through forces arising from quantum chromo-dynamics, nuclei exhibit both bound and unbound states, which can be strongly coupled. In this respect, one of the major challenges for computational nuclear physics, is to provide a unified description of structural and reaction properties of nuclei that is based on the fundamental underlying physics: the constituent nucleons and the realistic interactions among them. This requires a combination of innovative theoretical approaches and high-performance computing. In this contribution, we present one of such promising techniques, the ab initio no-core shell model/resonating-group method, and discuss applications to light nuclei scattering and fusion reactions that power stars and Earth-base fusion facilities.

  4. Dynamical dipole mode in fusion reactions

    SciTech Connect

    Pierroutsakou, D.; Boiano, A.; Romoli, M.; Martin, B.; Inglima, G.; La Commara, M.; Sandoli, M.; Agodi, C.; Alba, R.; Coniglione, R.; Zoppo, A. Del; Maiolino, C.; Piattelli, P.; Santonocito, D.; Sapienza, P.; Baran, V.; Glodariu, T.; Cardella, G.; De Filippo, E.; Pagano, A.

    2009-05-04

    We investigated the dynamical dipole mode, related with entrance channel charge asymmetry effects, in the {sup 40}Ar+{sup 92}Zr and {sup 36}Ar+{sup 96}Zr fusion reactions at E{sub lab} = 15.1 A and 16 A MeV, respectively. These reactions populate, through entrance channels having different charge asymmetries, a compound nucleus in the A = 126 mass energy region, identical spin distribution at an average excitation energy of about 280 MeV. The compound nucleus average excitation energy and average mass were deduced by the analysis of the light charged particle energy spectra. By studying the {gamma}-ray energy spectra and the {gamma}-ray angular distributions of the considered reactions, the dynamical nature of the prompt radiation related to the dynamical dipole mode was evidenced. The data are compared with calculations based on a collective bremsstrahlung analysis of the reaction dynamics.

  5. Nucleus-nucleus cold fusion reactions analyzed with the l-dependent 'fusion by diffusion' model

    SciTech Connect

    Cap, T.; Siwek-Wilczynska, K.; Wilczynski, J.

    2011-05-15

    We present a modified version of the Fusion by Diffusion (FBD) model aimed at describing the synthesis of superheavy nuclei in cold fusion reactions, in which a low excited compound nucleus emits only one neutron. The modified FBD model accounts for the angular momentum dependence of three basic factors determining the evaporation residue cross section: the capture cross section {sigma}{sub cap}(l), the fusion probability P{sub fus}(l), and the survival probability P{sub surv}(l). The fusion hindrance factor, the inverse of P{sub fus}(l), is treated in terms of thermal fluctuations in the shape degrees of freedom and is expressed as a solution of the Smoluchowski diffusion equation. The l dependence of P{sub fus}(l) results from the l-dependent potential energy surface of the colliding system. A new parametrization of the distance of starting point of the diffusion process is introduced. An analysis of a complete set of 27 excitation functions for production of superheavy nuclei in cold fusion reactions, studied in experiments at GSI Darmstadt, RIKEN Tokyo, and LBNL Berkeley, is presented. The FBD model satisfactorily reproduces shapes and absolute cross sections of all the cold fusion excitation functions. It is shown that the peak position of the excitation function for a given 1n reaction is determined by the Q value of the reaction and the height of the fission barrier of the final nucleus. This fact could possibly be used in future experiments (with well-defined beam energy) for experimental determination of the fission barrier heights.

  6. Synthesis of the heaviest nuclei in cold fusion reactions

    NASA Astrophysics Data System (ADS)

    Münzenberg, G.; Morita, K.

    2015-12-01

    Cold fusion of heavy ions paved the way to superheavy elements. It was proposed by Yu.Ts. Oganessian more than forty years ago in 1974 [1,2]. First experiments were carried out at JINR Dubna, starting with the reaction 40Ar + 208Pb → 248Fm* where several hundreds to thousand atoms were produced on one day. The large production rate indicating an enhancement of the fusion cross section, especially for the evaporation of two or three neutrons, proved the concept of cold-fusion with the use of the doubly magic nucleus 208Pb as a target. The Dubna experiments were extended to the transactinide region beyond rutherfordium. The breakthrough came with the separation in-flight. Two different approaches were used: kinematic separation with the velocity filter SHIP [3] at GSI Darmstadt, and with the gasfilled separator GARIS [4,5] at RIKEN. With SHIP the concept of cold fusion of massive nuclear systems was convincingly confirmed by the observation of the one-neutron evaporation channel in the production of 247Rf in an irradiation of 208Pb with 50Ti [6] in 1981 which opened the way to the transactinide region. At SHIP the elements bohrium (107) to copernicium (112) were discovered [7]. A new closed shell region around hassium was found. The RIKEN experiments started in 2002. They confirmed the GSI results and in addition improved the data on structure and production of elements hassium to copernicium significantly. The heaviest element ever created in a cold fusion reaction, Z = 113, was observed at GARIS [8,9].

  7. Trojan Horse particle invariance in fusion reactions

    NASA Astrophysics Data System (ADS)

    Pizzone, R. G.; Spitaleril, C.; Bertulani, C.; Mukhamedzhanov, A.; Blokhintsev, L.; La Cognata, M.; Lamia, L.; Spartá, R.; Tumino, A.

    2015-01-01

    Trojan Horse method plays an important part for the measurement of several charged particle induced reactions cross sections of astrophysical interest. In order to better understand its cornerstones and the related applications to different astrophysical scenarios several tests were performed to verify all its properties and the possible future perspectives. The Trojan Horse nucleus invariance for the binary reactions d(d,p)t, 6,7Li(p,α)3,4He was therefore tested using the appropriate quasi free break- ups, respectively. In the first cases results from 6Li and 3He break up were used, while for the lithium fusion reactions break-ups of 2H and 3He were compared. The astrophysical S(E)-factors for the different processes were then extracted in the framework of the PlaneWave Approximation applied to the different break-up schemes. The obtained results are compared with direct data as well as with previous indirect investigations. The very good agreement between data coming from different break-up schemes confirms the applicability of the plane wave approximation and suggests the independence of binary indirect cross section on the chosen Trojan Horse nucleus also for the present cases. Moreover the astrophysical implications of the results will also be discussed in details.

  8. Secondary Nuclear Reactions in Magneto-Inertial Fusion Plasmas

    NASA Astrophysics Data System (ADS)

    Knapp, Patrick

    2014-10-01

    The goal of Magneto-Inertial Fusion (MIF) is to relax the extreme pressure requirements of inertial confinement fusion by magnetizing the fuel. Understanding the level of magnetization at stagnation is critical for charting the performance of any MIF concept. We show here that the secondary nuclear reactions in magnetized deuterium plasma can be used to infer the magnetic field-radius product (BR), the critical confinement parameter for MIF. The secondary neutron yields and spectra are examined and shown to be extremely sensitive to BR. In particular, embedded magnetic fields are shown to affect profoundly the isotropy of the secondary neutron spectra. Detailed modeling of these spectra along with the ratio of overall secondary to primary neutron yields is used to form the basis of a diagnostic technique used to infer BR at stagnation. Effects of gradients in density, temperature and magnetic field strength are examined, as well as other possible non-uniform fuel configurations. Computational results employing a fully kinetic treatment of charged reaction product transport and Monte Carlo treatment of secondary reactions are compared to results from recent experiments at Sandia National Laboratories' Z machine testing the MAGnetized Liner Inertial Fusion (MagLIF) concept. The technique reveals that the charged reaction products were highly magnetized in these experiments. Implications for eventual ignition-relevant experiments with deuterium-tritium fuel are discussed. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under Contract DE-AC04-94AL85000.

  9. Description of the Fusion-Fission Reactions in the Framework of Dinuclear System Conception

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

    Within the dinuclear system model fusion-fission reactions 78Kr+40Ca and 86Kr+48Ca is investigated. The charge distributions of the decay products are predicted at bombarding energy 10 MeV/nucleon. The competition is treated between complete fusion followed by the decay of compound nucleus and quasifission channels. The possible explanation of the odd-even staggering in the yield of the final reaction products at high excitation energies is discussed.

  10. Fusion hindrance in reactions with very heavy ions: Border between normal and hindered fusion

    SciTech Connect

    Shen Caiwan; Li Qingfeng; Boilley, David; Shen Junjie; Abe, Yasuhisa

    2011-05-15

    The fusion hindrance in heavy-ion collisions is studied in the framework of the two-center liquid drop model. It appears that the neck and the radial degrees of freedom might both be hampered by an inner potential barrier on their path between the contact configuration to the compound nucleus. Heavy-ion reactions with and without the two kinds of fusion hindrance are classified through systematic calculations. It is found that the number of reactions without radial fusion hindrance is much smaller than that without neck fusion hindrance, and for both kinds of fusion hindrance the number of reactions without fusion hindrance at small mass-asymmetry parameter {alpha} is smaller than that at large {alpha}. In the formation of a given compound nucleus, if a reaction with {alpha}{sub c} is not hindered, then other reactions with {alpha}>{alpha}{sub c} are also not hindered, as is well known experimentally.

  11. Fusion reactions of Ni,6458+124Sn

    NASA Astrophysics Data System (ADS)

    Jiang, C. L.; Stefanini, A. M.; Esbensen, H.; Rehm, K. E.; Almaraz-Calderon, S.; Avila, M. L.; Back, B. B.; Bourgin, D.; Corradi, L.; Courtin, S.; Fioretto, E.; Galtarossa, F.; Goasduff, A.; Haas, F.; Mazzocco, M. M.; Montanari, D.; Montagnoli, G.; Mijatovic, T.; Sagaidak, R.; Santiago-Gonzalez, D.; Scarlassara, F.; Strano, E. E.; Szilner, S.

    2015-04-01

    Measurements of fusion excitation functions of 58Ni+124Sn and 64Ni+124Sn are extended towards lower energy to cross sections of 1 μ b and are compared to detailed coupled-channels calculations. The calculations clearly show the importance of including transfer reactions in a coupled-channels treatment for such heavy systems. This result is different from the conclusion made in a previous article which claimed that the influence of transfer on fusion is not important for fusion reactions of Ni +Sn . In the energy region studied in this experiment no indication of fusion hindrance has been observed, which is consistent with a systematic study of this behavior.

  12. Evaluation of charged-particle reactions for fusion applications

    SciTech Connect

    White, R.M.; Resler, D.A.; Warshaw, S.I.

    1991-01-01

    New evaluations of the total reaction cross sections for {sup 2}H(d,n){sup 3}He, {sup 2}H(d,p){sup 3}H, {sup 3}H(t,2n){sup 4}He,{sup 3}H(d,n){sup 4}He, and {sup 3}He(d,p){sup 4}He have been completed. These evaluations are based on all known published data from 1946 to 1990 and include over 1150 measured data points from 67 references. The purpose of this work is to provide a consistent and well-documented set of cross sections for use in calculations relating to fusion energy research. A new thermonuclear data file, TDF, and a library of FORTRAN subprograms to read the file have been developed. Calculated from the new evaluations, the TDF file contains information on the Maxwellian-averaged reaction rates as a function of reaction and plasma temperature and the Maxwellian-averaged average energy of the interacting particles and reaction products. Routines are included that provide thermally-broadened spectral information for the secondary reaction products. 67 refs., 18 figs.

  13. Observation of neutronless fusion reactions in picosecond laser plasmas.

    PubMed

    Belyaev, V S; Matafonov, A P; Vinogradov, V I; Krainov, V P; Lisitsa, V S; Roussetski, A S; Ignatyev, G N; Andrianov, V P

    2005-08-01

    The yield of alpha particles in neutronless fusion reactions 11B +p in plasmas produced by picosecond laser pulses with the peak intensity of 2 x 10(18) W/cm2 has been observed. Experiments were carried out on the "Neodymium" laser facility at the pulse energy of 10-12 J and pulse duration of 1.5 ps. The composite targets 11B + (CH2)n were used. The yield of 10(3) alpha particles per pulse has been observed. The energy spectrum of alpha particles contains two maxima: at 3-4 MeV and at 6-10 MeV . The first of these peaks corresponds to the secondary alpha12 particles at the decay of the intermediate first excited state of 8Be, whereas the second peak demonstrates generation of alpha1 particles in the reaction 11B +p with the production of this excited state. Simultaneous measurements of neutrons result in zero yield, which proves the observation of neutronless fusion reactions in our experiments. PMID:16196717

  14. Measuring D(d,p)T fusion reactant energy spectra with Doppler shifted fusion products

    SciTech Connect

    Boris, D. R.; Kulcinski, G. L.; Santarius, J. F.; Donovan, D. C.; Piefer, G. R.

    2010-06-15

    Deuterium fusion reactant energy spectra have been measured using a diagnostic that records the Doppler shift imparted to charged particle fusion products of the D(d,p)T reaction by the center-of-mass velocity of the deuterium reactants. This diagnostic, known as the fusion ion Doppler shift diagnostic (FIDO) measures fast deuterium energy spectra in the inertial electrostatic confinement (IEC) experiment at the University of Wisconsin-Madison {l_brace}Santarius et al. [Fusion Sci. Technol. 47, 1238 (2005)]{r_brace}, a device to confine high energy light ions in a spherically symmetric, electrostatic potential well. This article details the first measurements of the fusion reactant energy spectra in an IEC device as well as the design and principles of operation of the FIDO diagnostic. Scaling of reactant energy spectra with a variety of experimental parameters have been explored.

  15. Light nuclei production in fusion of heavy ions

    SciTech Connect

    Antonenko, N.V.; Ivanova, S.P.; Jolos, R.V.; Scheid, W. Joint Institute for Nuclear Research, 141980 Dubna )

    1994-10-01

    A possible mechanism of the production of light nuclei in fusion reactions is considered. It is shown that the decay of the dinuclear system during its evolution to a compound nucleus yields a substantial rate for the production of light nuclei. The cross section of this process is calculated for the reaction [sup 58]Ni+[sup 58]Ni. The coupling of other modes of motion causes an increase of the asymmetric decay of the dinuclear system.

  16. Fusion probability for neutron-rich radioactive Sn induced reactions

    SciTech Connect

    Liang, J Felix; Gross, Carl J; Kohley, Zachary W; Shapira, Dan; Varner Jr, Robert L; Allmond, James M; Caraley, Anne L; Lagergren, Karin B; Mueller, Paul Edward

    2012-01-01

    Evaporation residue cross sections for $^{124,126,127,128}$Sn+$^{64}$Ni and $^{132}$Sn+$^{58}$Ni have been measured to study the effects of neutron excess in neutron-rich radioactive nuclei on fusion. For the reactions with $^{64}$Ni, the fusion probability does not decrease with increasing neutron excess in Sn, contrary to the result of the stable beam Sn+Zr measurement. A comparison of the reduced evaporation residue cross sections for $^{126}$Sn+$^{64}$Ni and $^{132}$Sn+$^{58}$Ni, which make the same compound nucleus, shows that the fusion probability is indistinguishable for reactions involving the same atomic elements but different isotope combinations.

  17. Calculation of fusion product angular correlation coefficients for fusion plasmas

    SciTech Connect

    Murphy, T.J.

    1987-08-01

    The angular correlation coefficients for fusion products are calculated in the cases of Maxwellian and beam-target plasmas. Measurement of these coefficients as a localized ion temperature or fast-ion diagnostic is discussed. 8 refs., 7 figs., 1 tab.

  18. The new possibility of the fusion p + 11B chain reaction being induced by intense laser pulses

    NASA Astrophysics Data System (ADS)

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

    2015-09-01

    We discuss the experimental and theoretical principal schemes of a thermonuclear reactor, based on the fusion reaction p + 11B: beam collisions, fusion in degenerate plasmas, ignition at the plasma, particle acceleration by nonlinear ponderomotive forces and irradiation of the solid 11B target by a proton beam at the Coulomb explosion of hydrogen microdroplets. The fusion reaction p + 11B can be initiated by ultrashort high intensity laser pulses under conditions far from thermodynamic equilibrium. This may result in fusion products containing a small amount of neutrons and other nuclear radiation effects. It was found that the fusion reaction p + 11B produces further nuclear reactions and generates high-energy protons. The latter can support the chain reaction process. Our approach allows us to also investigate nuclear reactions in the early Universe and in stars.

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

    SciTech Connect

    Heusch, B; Beck, C; Coffin, J P; Freeman, R M; Gallmann, A; Haas, F; Rami, F; Wagner, P; Alburger, D E

    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.

  20. Cherenkov neutron detector for fusion reaction and runaway electron diagnostics

    SciTech Connect

    Cheon, MunSeong 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.

  1. Cherenkov neutron detector for fusion reaction and runaway electron diagnostics.

    PubMed

    Cheon, MunSeong; Kim, Junghee

    2015-08-01

    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. PMID:26329194

  2. Compound nucleus formation in reactions between massive nuclei: Fusion barrier

    SciTech Connect

    Antonenko, N.V.; Cherepanov, E.A.; Nasirov, A.K.; Permjakov, V.P.; Volkov, V.V.

    1995-05-01

    The evaporation residue cross sections {sigma}{sub ER} in reactions between massive nuclei have been analyzed within different models of complete fusion. The calculations in the framework of the optical model, the surface friction model, and the macroscopic dynamic model can give the results which are by few orders of magnitude different from experimental data. This takes place due to neglect of the competition between complete fusion and quasifission. A possible mechanism of compound nucleus formation in heavy-ion-induced reactions has been suggested. The analysis of the complete fusion of nuclei on the basis of dinuclear system approach has allowed one to reveal an important feature of the fusion process of massive nuclei, that is, the appearance of the fusion barrier during dinuclear system evolution to a compound nucleus. As a result, the competition between complete fusion and quasifission arises and strongly reduces the cross section of the compound nucleus formation. A model is proposed for calculation of this competition in a massive symmetric dinuclear system. This model is applied for collision energies above the Coulomb barrier. The {sigma}{sub ER} values calculated in the framework of dinuclear system approach seem to be close to the experimental data. For illustration the reactions {sup 100}Mo+{sup 100}Mo, {sup 110}Pd+{sup 110}Pd, and {sup 124}Sn+{sup 96}Zr have been considered.

  3. Fission and Quasifission in the 'Warm' Fusion Reactions

    SciTech Connect

    Itkis, M. G.; Bogachev, A. A.; Chernysheva, E. V.; Itkis, I. M.; Knyazheva, G. N.; Kozulin, E. M.

    2010-06-01

    Mass-energy distributions, as well as capture cross-section of fission-like fragments for the reactions of {sup 48}Ca, {sup 58}Fe and {sup 64}Ni ions with actinides leading to the formation of superheavy compound system with Z = 112-120 at energies near the Coulomb barrier have been measured. Fusion-fission cross sections were estimated from the analysis of mass and total kinetic energy distributions. It was found that the fusion probability is approximately the same for the reactions with {sup 48}Ca ions and drops three orders of magnitude at the transition to {sup 64}Ni ions.

  4. Isotopic dependence of fusion cross sections in reactions with heavy nuclei

    NASA Astrophysics Data System (ADS)

    Adamian, G. G.; Antonenko, N. V.; Scheid, W.

    2000-09-01

    The dependence of fusion cross section on the isotopic composition of colliding nuclei is analysed within the dinuclear system concept for compound nucleus formation. Probabilities of fusion and surviving probabilities, ingredients of the evaporation residue cross sections, depend decisively on the neutron numbers of the dinuclear system. Evaporation residue cross sections for the production of actinides and superheavy nuclei, listed in table form, are discussed and compared with existing experimental data. In the Pb-based reactions neutron-rich radioactive projectiles are shown to lead to similar fusion cross sections as stable projectiles.

  5. Acrosome Reaction as a Preparation for Gamete Fusion.

    PubMed

    Cuasnicú, Patricia S; Da Ros, Vanina G; Weigel Muñoz, Mariana; Cohen, Débora J

    2016-01-01

    The acrosome reaction (AR) is a universal requisite for sperm-egg fusion. However, whereas through the animal kingdom fusion of spermatozoa with the egg plasma membrane occurs via the inner acrosomal membrane exposed after the AR, in eutherian mammals, gamete fusion takes place through a specialized region of the acrosome known as the equatorial segment (ES) which becomes fusogenic only after the AR is completed. This chapter focuses on the different molecular mechanisms involved in the acquisition of the fusogenicity of the ES after the AR. We provide an update of the knowledge about the proteins proposed to have a role in this process either by modifying cytoskeletal and/or membrane molecules or by relocalizing to the ES after the AR to subsequently participate in gamete fusion. PMID:27194355

  6. Incomplete fusion reactions in 16O+159Tb system: Spin distribution measurements

    NASA Astrophysics Data System (ADS)

    Sharma, Vijay R.; Yadav, Abhishek; Singh, Devendra P.; Singh, Pushpendra P.; Gupta, Sunita; Sharma, Manoj K.; Bala, Indu; Kumar, R.; Muralithar, S.; Singh, R. P.; Singh, B. P.; Prasad, R.; Bhowmik, R. K.

    2015-01-01

    In order to explore the reaction modes on the basis of their entry state spin population, an experiment has been done by employing particle-γ coincidence technique carried out at the Inter University Accelerator Centre, New Delhi. The preliminary analysis conclusively demonstrates, spin distribution for some reaction products populated via complete and/or incomplete fusion of 16O with 159Tb system found to be distinctly different. Further, the existence of incomplete fusion at low bombarding energies indicates the possibility to populate high spin states.

  7. Microdroplet fusion mass spectrometry for fast reaction kinetics

    PubMed Central

    Lee, Jae Kyoo; Kim, Samuel; Nam, Hong Gil; Zare, Richard N.

    2015-01-01

    We investigated the fusion of high-speed liquid droplets as a way to record the kinetics of liquid-phase chemical reactions on the order of microseconds. Two streams of micrometer-size droplets collide with one another. The droplets that fused (13 μm in diameter) at the intersection of the two streams entered the heated capillary inlet of a mass spectrometer. The mass spectrum was recorded as a function of the distance x between the mass spectrometer inlet and the droplet fusion center. Fused droplet trajectories were imaged with a high-speed camera, revealing that the droplet fusion occurred approximately within a 500-μm radius from the droplet fusion center and both the size and the speed of the fused droplets remained relatively constant as they traveled from the droplet fusion center to the mass spectrometer inlet. Evidence is presented that the reaction effectively stops upon entering the heated inlet of the mass spectrometer. Thus, the reaction time was proportional to x and could be measured and manipulated by controlling the distance x. Kinetic studies were carried out in fused water droplets for acid-induced unfolding of cytochrome c and hydrogen–deuterium exchange in bradykinin. The kinetics of the former revealed the slowing of the unfolding rates at the early stage of the reaction within 50 μs. The hydrogen–deuterium exchange revealed the existence of two distinct populations with fast and slow exchange rates. These studies demonstrated the power of this technique to detect reaction intermediates in fused liquid droplets with microsecond temporal resolution. PMID:25775573

  8. Accelerators for Inertial Fusion Energy Production

    NASA Astrophysics Data System (ADS)

    Bangerter, R. O.; Faltens, A.; Seidl, P. A.

    2014-02-01

    Since the 1970s, high energy heavy ion accelerators have been one of the leading options for imploding and igniting targets for inertial fusion energy production. Following the energy crisis of the early 1970s, a number of people in the international accelerator community enthusiastically began working on accelerators for this application. In the last decade, there has also been significant interest in using accelerators to study high energy density physics (HEDP). Nevertheless, research on heavy ion accelerators for fusion has proceeded slowly pending demonstration of target ignition using the National Ignition Facility (NIF), a laser-based facility at Lawrence Livermore National Laboratory. A recent report of the National Research Council recommends expansion of accelerator research in the US if and when the NIF achieves ignition. Fusion target physics and the economics of commercial energy production place constraints on the design of accelerators for fusion applications. From a scientific standpoint, phase space and space charge considerations lead to the most stringent constraints. Meeting these constraints almost certainly requires the use of multiple beams of heavy ions with kinetic energies > 1 GeV. These constraints also favor the use of singly charged ions. This article discusses the constraints for both fusion and HEDP, and explains how they lead to the requirements on beam parameters. RF and induction linacs are currently the leading contenders for fusion applications. We discuss the advantages and disadvantages of both options. We also discuss the principal issues that must yet be resolved.

  9. Reaction product imaging

    SciTech Connect

    Chandler, D.W.

    1993-12-01

    Over the past few years the author has investigated the photochemistry of small molecules using the photofragment imaging technique. Bond energies, spectroscopy of radicals, dissociation dynamics and branching ratios are examples of information obtained by this technique. Along with extending the technique to the study of bimolecular reactions, efforts to make the technique as quantitative as possible have been the focus of the research effort. To this end, the author has measured the bond energy of the C-H bond in acetylene, branching ratios in the dissociation of HI, the energetics of CH{sub 3}Br, CD{sub 3}Br, C{sub 2}H{sub 5}Br and C{sub 2}H{sub 5}OBr dissociation, and the alignment of the CD{sub 3} fragment from CD{sub 3}I photolysis. In an effort to extend the technique to bimolecular reactions the author has studied the reaction of H with HI and the isotopic exchange reaction between H and D{sub 2}.

  10. Charged Fusion Product Detector Study

    NASA Astrophysics Data System (ADS)

    Lopez, Carlos

    2014-03-01

    Plasmas are hot ionized gases which may be manipulated by electromagnetic fields in machines called tokamaks, which are experimental reactors created to harness energy when fusion occurs in said plasma. In order to study instabilities within the tokamak plasma, the trajectories of protons were studied with an array of silicon surface barrier detectors. The collection efficiency of the detectors was analyzed in order to make more accurate calculations, where particular attention was paid to the solid angle of acceptance, or the angular distribution through which particles would enter into the detector. Monte Carlo simulations were coded and implemented in the Python language, where a point on the grid acted as a source which one million data points shot at the plane of the detector. The ratio of the hits versus the misses was calculated for varying positions of the source relative to the plane of the detector. These results were compared to an alpha particle spectroscopy experiment, where a radiation source emitting alpha particles was placed at varying positions relative to the detector. The counting rate of the detector was then observed when it was exposed to the source, and this along with the Monte Carlo results were implemented into an efficiency calculation. DOE Grant # DE-SC0001157.

  11. Yield decomposition and excitation energy reconstruction in an incomplete fusion reaction

    SciTech Connect

    Chbihi, A.; Sobotka, L.G.; Majka, Z.; Sarantites, D.G.; Stracener, D.W.; Abenante, V.; Semkow, T.M.; Nicolis, N.G. ); Hensley, D.C.; Beene, J.R.; Halbert, M.L. )

    1991-02-01

    The velocity distribution of fusionlike products formed in the reaction 701 MeV {sup 28}Si+{sup 100}Mo is decomposed into 26 incomplete fusion channels. If Coulomb corrections are neglected the yields of the incomplete fusion channels correlate much better with the {ital Q} value for projectile fragmentation than with the {ital Q} value for incomplete fusion. However, the correlation is much improved for incomplete fusion if a Coulomb correction is included. The partition of linear momentum between various sources is deduced using the measured residue velocity, multicomponent fits to light charged particle spectra, and mean neutron multiplicities. This reconstruction indicates that a substantial fraction of the momentum is not detected by our apparatus when slow residues are produced. With reasonable assumptions about this missing momentum component, the initial excitation of the compoundlike system is calculated as a function of the residue velocity.

  12. Target production for inertial fusion energy

    SciTech Connect

    Woodworth, J.G.; Meier, W.

    1995-03-01

    Inertial fusion energy (IFE) power plants will require the ignition and burn of 5-10 fusion fuel targets every second. The technology to economically mass produce high-quality, precision targets at this rate is beyond the current state of the art. Techniques that are scalable to high production rates, however, have been identified for all the necessary process steps, and many have been tested in laboratory experiments or are similar to current commercial manufacturing processes. In this paper, we describe a baseline target factory conceptual design and estimate its capital and operating costs. The result is a total production cost of {approximately}16{cents} per target. At this level, target production represents about 6% of the estimated cost of electricity from a 1-GW{sub e} IFE power plant. Cost scaling relationships are presented and used to show the variation in target cost with production rate and plant power level.

  13. Angular momentum effects in fusion-fission and fusion-evaporation reactions

    SciTech Connect

    Plasil, F.

    1980-01-01

    The study of heavy-ion fusion reactions is complicated by the possible contributions of several mechanisms. The various types of heavy-ion-induced fission are discussed. Then compound-nucleus fission is considered with reference to fission barriers deduced from heavy-ion-induced fission. Next, the problems associated with measured values of evaporation-residue cross sections and the angular momentum dependence of incomplete fusion are examined. Finally, the de-excitation of compound nuclei is again taken up, this time with reference to the greatly enhanced ..cap alpha.. emission predicted on the basis of the rotating liquid drop model. 24 figures. (RWR)

  14. 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.

  15. Distribution of Ions in Laser-Driven Fusion Reactions

    NASA Astrophysics Data System (ADS)

    Warrens, Mackenzie; Barbarino, Matteo; Bonasera, Aldo; Lattuada, Dario; Group Bonasera Team

    2015-10-01

    Experiments of laser-driven fusion reactions are important for many aspects, such as measuring the cross section of plasma. In the experiments at University of Texas using the Texas Petawatt laser, deuterium clusters of various sizes suspended in 3He gas absorb the laser's energy and are irradiated. The clusters undergo a Coulomb explosion, forming a hot plasma which initiates the reactions. This analysis studies two possible fusions: D(d, 3He)n and 3He(d,p)4He. Signals are recorded using a Faraday cup detector, then transformed and analyzed in energy space. In this work, we investigate if the log-normal distribution is an appropriate description of the energy distribution of the ions. If the log-normal distribution is a good fit, the energy distribution can be thought of as chaotic enough to appear thermalized. The chaos may be due to many-body interactions over long distances, as well as the different charges and masses of the particles involved. Using the well-known S-factor for the two reactions and the extrapolated fits, the number of fusions is calculated and compared with experimental data. This material is based upon work supported by the National Science Foundation Graduate Research Fellowship under Grant No. 1263281.

  16. f 1 (1285) formation in photon-photon fusion reactions

    NASA Astrophysics Data System (ADS)

    Aihara, H.; Alston-Garnjost, M.; Avery, R. E.; Barbaro-Galtieri, A.; Barker, A. R.; Barnett, B. A.; Bauer, D. A.; Bay, A.; Bengtsson, H.-U.; Bobbink, G. J.; Buchanan, C. D.; Buijs, A.; Caldwell, D. O.; Chao, H.-Y.; Chun, S.-B.; Clark, A. R.; Cowan, G. D.; Crane, D. A.; Dahl, O. I.; Daoudi, M.; Derby, K. A.; Eastman, J. J.; Eberhard, P. H.; Edberg, T. K.; Eisner, A. M.; Enomoto, R.; Erné, F. C.; Fairfield, K. H.; Hauptman, J. M.; Hofmann, W.; Hylen, J.; Kamae, T.; Kaye, H. S.; Kenney, R. W.; Khacheryan, S.; Kofler, R. R.; Langeveld, W. G. J.; Layter, J. G.; Lin, W. T.; Linde, F. L.; Loken, S. C.; Lu, A.; Lynch, G. R.; Madaras, R. J.; Magnuson, B. D.; Masek, G. E.; Mathis, L. G.; Matthews, J. A. J.; Maxfield, S. J.; Miller, E. S.; Moses, W.; Nygren, D. R.; Oddone, P. J.; Paar, H. P.; Park, S. K.; Pellett, D. E.; Pripstein, M.; Ronan, M. T.; Ross, R. R.; Rouse, F. R.; Schwitkis, K. A.; Sens, J. C.; Shapiro, G.; Shen, B. C.; Slater, W. E.; Smith, J. R.; Steinman, J. S.; Stephens, R. W.; Stevenson, M. L.; Stork, D. H.; Strauss, M. G.; Sullivan, M. K.; Takahashi, T.; Toutounchi, S.; Van Tyen, R.; Van Dalen, G. J.; Vernon, W.; Wagner, W.; Wang, E. M.; Wang, Y.-X.; Wenzel, W. A.; Wolf, Z. R.; Yamamoto, H.; Yellin, S. J.; Zeitlin, C.; TPC/Two-Gamma Collaboration

    1988-07-01

    We have observed formation of the f 1 (1285) in the reaction e +e -→e +e -π+π-η( η→ γγ). Its γγ ∗ width is determined in several Q2 bins. The γγ coupling parameter for the f 1 (1285) is found to be 2.4±0.5±0.5 keV. This value is compared to that for the X (1420), another J=1 state formed in γγ fusion reactions, which may belong to the same meson nonet.

  17. Fusion and direct reactions for strongly and weakly bound projectiles

    NASA Astrophysics Data System (ADS)

    Hugi, M.; Lang, J.; Müller, R.; Ungricht, E.; Bodek, K.; Jarczyk, L.; Kamys, B.; Magiera, A.; Strzałkowski, A.; Willim, G.

    1981-09-01

    The interaction of 6Li, 9Be and 12C projectiles with a 28Si target was investigated by measuring the angular distributions of the elastically scattered projectiles and of the emitted protons, deuterons and α-particles. The experiment was performed in order to deduce direct and compound nucleus process contributions to the total reaction cross section and to study the influence of the projectile structure on the relative importance of these two mechanisms. Optical model parameters and therefore the total reaction cross section are strongly influenced by the binding energy of the projectile. The parameters of the Glas-Mosel model describing the fusion reaction vary smoothly with the atomic number. In the system 9Be + 28Si around 50% of all reactions are direct processes even at energies near the Coulomb barrier, whereas in the other systems the direct part amounts to 15 % ( 12C) and 30 % ( 6Li) only.

  18. Understanding fuel magnetization and mix using secondary nuclear reactions in magneto-inertial fusion.

    PubMed

    Schmit, P F; Knapp, 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; Chandler, G A; Cooper, G W; Cuneo, M E; Geissel, M; Harvey-Thompson, A J; Herrmann, M C; Hess, M H; Johns, O; Lamppa, D C; Martin, M R; McBride, R D; Porter, J L; Robertson, G K; Rochau, G A; Rovang, D C; Ruiz, C L; Savage, M E; Smith, I C; Stygar, W A; Vesey, R A

    2014-10-10

    Magnetizing the fuel in inertial confinement fusion relaxes ignition requirements by reducing thermal conductivity and changing the physics of burn product confinement. Diagnosing the level of fuel magnetization during burn is critical to understanding target performance in magneto-inertial fusion (MIF) implosions. In pure deuterium fusion plasma, 1.01 MeV tritons are emitted during deuterium-deuterium fusion and can undergo secondary deuterium-tritium reactions before exiting the fuel. Increasing the fuel magnetization elongates the path lengths through the fuel of some of the tritons, enhancing their probability of reaction. Based on this feature, a method to diagnose fuel magnetization using the ratio of overall deuterium-tritium to deuterium-deuterium neutron yields is developed. Analysis of anisotropies in the secondary neutron energy spectra further constrain the measurement. Secondary reactions also are shown to provide an upper bound for the volumetric fuel-pusher mix in MIF. The analysis is applied to recent MIF experiments [M. R. Gomez et al., Phys. Rev. Lett. 113, 155003 (2014)] on the Z Pulsed Power Facility, indicating that significant magnetic confinement of charged burn products was achieved and suggesting a relatively low-mix environment. Both of these are essential features of future ignition-scale MIF designs. PMID:25375715

  19. Understanding Fuel Magnetization and Mix Using Secondary Nuclear Reactions in Magneto-Inertial Fusion

    NASA Astrophysics Data System (ADS)

    Schmit, P. F.; Knapp, 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.; Chandler, G. A.; Cooper, G. W.; Cuneo, M. E.; Geissel, M.; Harvey-Thompson, A. J.; Herrmann, M. C.; Hess, M. H.; Johns, O.; Lamppa, D. C.; Martin, M. R.; McBride, R. D.; Porter, J. L.; Robertson, G. K.; Rochau, G. A.; Rovang, D. C.; Ruiz, C. L.; Savage, M. E.; Smith, I. C.; Stygar, W. A.; Vesey, R. A.

    2014-10-01

    Magnetizing the fuel in inertial confinement fusion relaxes ignition requirements by reducing thermal conductivity and changing the physics of burn product confinement. Diagnosing the level of fuel magnetization during burn is critical to understanding target performance in magneto-inertial fusion (MIF) implosions. In pure deuterium fusion plasma, 1.01 MeV tritons are emitted during deuterium-deuterium fusion and can undergo secondary deuterium-tritium reactions before exiting the fuel. Increasing the fuel magnetization elongates the path lengths through the fuel of some of the tritons, enhancing their probability of reaction. Based on this feature, a method to diagnose fuel magnetization using the ratio of overall deuterium-tritium to deuterium-deuterium neutron yields is developed. Analysis of anisotropies in the secondary neutron energy spectra further constrain the measurement. Secondary reactions also are shown to provide an upper bound for the volumetric fuel-pusher mix in MIF. The analysis is applied to recent MIF experiments [M. R. Gomez et al., Phys. Rev. Lett. 113, 155003 (2014), 10.1103/PhysRevLett.113.155003] on the Z Pulsed Power Facility, indicating that significant magnetic confinement of charged burn products was achieved and suggesting a relatively low-mix environment. Both of these are essential features of future ignition-scale MIF designs.

  20. Formation of superheavy elements in cold fusion reactions

    NASA Astrophysics Data System (ADS)

    Smolańczuk, Robert

    2001-04-01

    We calculate the formation cross sections of transactinides (superheavy elements), as well as heavy actinides (No and Lr), which have been or might be obtained in fusion reactions with the evaporation of only one neutron. We use both more realistic fusion barrier and survival probability of the compound nucleus in comparison with the original phenomenological model [Phys. Rev. C 59, 2634 (1999)] that prompted the Berkeley experiment on the synthesis of a new superheavy element 118 [Phys. Rev. Lett. 83, 1104 (1999)]. Calculations are performed for asymmetric and symmetric target-projectile combinations and for reactions with stable and radioactive-ion beams. The formation cross sections measured at GSI-Darmstadt for transactinides and heavy actinides, as well as that for superheavy element 118 reported by the LBNL-Berkeley group, are reproduced within a factor of 2.4, on average. Based on the obtained relatively large cross sections, we predict that optimal reactions with stable beams for the synthesis of so far unobserved superheavy elements 119, 120, and 121 are 209Bi(86Kr, 1n)294119, 208Pb(88Sr, 1n)295120, and 209Bi(88Sr, 1n)296121, respectively. This is because of the magic of both the target and the projectile that leads to larger Q value and, consequently, lower effective fusion barrier with larger transmission probability. The same effect is responsible for relatively large cross sections predicted for the symmetric reactions 136Xe(124Sn, 1n)259Rf, 136Xe(136Xe, 1n)271Hs,138Ba(136Xe, 1n)273110, and 140Ce(136Xe, 1n)275112. Although shell effects in the magic nuclei 124Sn, 136Xe, 138Ba, and 140Ce are not as strong as in 208Pb and 209Bi, they act on both the target and the projectile and lead to the prediction of measurable cross sections.

  1. Fusion reactions of 58,64Ni+124Sn

    NASA Astrophysics Data System (ADS)

    Galtarossa, F.; Jiang, C. L.; Stefanini, A. M.; Esbensen, H.; Rehm, K. E.; Almaraz Calderon, S.; Avila, M. L.; Back, B. B.; Bourgin, D.; Corradi, L.; Courtin, S.; Fioretto, E.; Goasduff, A.; Haas, F.; Mazzocco, M.; Montanari, D.; Montagnoli, G.; Mijiatovic, T.; Sagaidak, R.; Santiago-Gonzalez, D.; Scarlassara, F.; Strano, E.; Szilner, S.

    2016-05-01

    In order to better understand the influence of transfer in sub-barrier nuclear reactions, cross sections for the system 58,64Ni+124Sn have been measured down to 0.5-1 µb and compared to detailed coupledchannel calculations. In agreement with a phenomenological Q-value systematics, calculations show the importance of including the coupling to the transfer channel for these heavy systems. No clear evidence of fusion hindrance is observed, probably due to the fact that the cross sections measured in this experiment are not low enough for the appearance of that phenomenon.

  2. Impact of Reaction Cross Section on the Unified Description of Fusion Excitation Function

    NASA Astrophysics Data System (ADS)

    Basrak, Z.; Eudes, P.; de la Mota, V.; Sébille, F.; Royer, G.

    A systematics of over 300 complete and incomplete fusion cross section data points covering energies beyond the barrier for fusion is presented. Owing to a usual reduction of the fusion cross sections by the total reaction cross sections and an original scaling of energy, a fusion excitation function common to all the data points is established. A universal description of the fusion exci- tation function relying on basic nuclear concepts is proposed and its dependence on the reaction cross section used for the cross section normalization is discussed. The pioneering empirical model proposed by Bass in 1974 to describe the complete fusion cross sections is rather successful for the incomplete fusion too and provides cross section predictions in satisfactory agreement with the observed universality of the fusion excitation function. The sophisticated microscopic transport DYWAN model not only reproduces the data but also predicts that fusion reaction mechanism disappears due to weakened nuclear stopping power around the Fermi energy.

  3. Synthesis of superheavy nuclei: A search for new production reactions

    SciTech Connect

    Zagrebaev, Valery; Greiner, Walter

    2008-09-15

    Nuclear reactions leading to the formation of new superheavy (SH) elements and isotopes are discussed in the paper. 'Cold' and 'hot' synthesis, fusion of fission fragments, transfer reactions, and reactions with radioactive ion beams are analyzed along with their abilities and limitations. If the possibility of increasing the beam intensity and the detection efficiency (by a total of one order of magnitude) is found, then several isotopes of new elements with Z=120-124 could be synthesized in fusion reactions of titanium, chromium, and iron beams with actinide targets. The use of light- and medium-mass neutron-rich radioactive beams may help us fill the gap between the SH nuclei produced in the hot fusion reactions and the mainland. In these reactions, we may really approach the 'island of stability.' Such a possibility is also provided by the multinucleon transfer processes in low-energy damped collisions of heavy actinide nuclei. The production of SH elements in fusion reactions with accelerated fission fragments looks less encouraging.

  4. Thermochemical hydrogen production based on magnetic fusion

    SciTech Connect

    Krikorian, O.H.; Brown, L.C.

    1982-06-10

    Conceptual design studies have been carried out on an integrated fusion/chemical plant system using a Tandem Mirror Reactor fusion energy source to drive the General Atomic Sulfur-Iodine Water-Splitting Cycle and produce hydrogen as a future feedstock for synthetic fuels. Blanket design studies for the Tandem Mirror Reactor show that several design alternatives are available for providing heat at sufficiently high temperatures to drive the General Atomic Cycle. The concept of a Joule-boosted decomposer is introduced in one of the systems investigated to provide heat electrically for the highest temperature step in the cycle (the SO/sub 3/ decomposition step), and thus lower blanket design requirements and costs. Flowsheeting and conceptual process designs have been developed for a complete fusion-driven hydrogen plant, and the information has been used to develop a plot plan for the plant and to estimate hydrogen production costs. Both public and private utility financing approaches have been used to obtain hydrogen production costs of $12-14/GJ based on July 1980 dollars.

  5. Sparking fusion: A step toward laser-initiated nuclear fusion reactions

    SciTech Connect

    Peterson, I.

    1996-10-19

    The fusion furnace at the sun`s core burns hydrogen to make helium. Each time two hydrogen nuclei, or protons, merge to create a deuterium nucleus, the process releases energy. A chain of additional energy-producing nuclear reactions then converts deuterium into helium. Because protons, with their like electric charges, naturally repel each other, high temperatures and tremendous pressures are needed to force them together closely enough to initiate and sustain the reactions. These mergers cost energy initially, but the return on that investment proves prodigious. On Earth, such an energy payoff has been achieved only in the uncontrolled fury of a detonated hydrogen bomb. The vision of harnessing and controlling nuclear fusion as a terrestrial energy source has yet to be fulfilled. The proposed National Ignition Facility (NIF) represents an ambitious effort to use powerful lasers to deposit sufficient energy in a small capsule of nuclear fuel to trigger fusion. The main justification for the project is to ensure that a core group of physicists and engineers maintains its expertise in the physics of nuclear weapons. This article presents both the scientific and political sides of the NIF facility.

  6. Production of recombinant peptides as fusions with SUMO.

    PubMed

    Satakarni, Makkapati; Curtis, Robin

    2011-08-01

    Recombinant production of non-native peptides requires using protein fusion technology to prevent peptide degradation by host-cell proteases. In this work, we have used SUMO protein as a fusion partner for the production of difficult-to-express, antimicrobial, self-assembling and amyloidogenic peptides using Escherichia coli. SUMO-peptide fusions were expressed as intracellular products by utilizing pET based expression vectors constructed by Life Sensors Inc., USA. Histidine tagged SUMO-peptide fusions were purified using Ni-NTA affinity chromatography. Complete (100%) cleavage of the SUMO-peptide fusion was achieved using SUMO protease-1. Our findings demonstrate that SUMO fusion technology is a promising alternative for production of peptides in E. coli. The key advantage of this technology is that the enzymatic activity of SUMO protease-1 is specific and efficient leading to inexpensive costs for cleaving the peptide fusion when compared with other fusion systems. PMID:21586326

  7. A classical approach in simple nuclear fusion reaction {sub 1}H{sup 2}+{sub 1}H{sup 3} using two-dimension granular molecular dynamics model

    SciTech Connect

    Viridi, S.; Kurniadi, R.; Waris, A.; Perkasa, Y. S.

    2012-06-06

    Molecular dynamics in 2-D accompanied by granular model provides an opportunity to investigate binding between nuclei particles and its properties that arises during collision in a fusion reaction. A fully classical approach is used to observe the influence of initial angle of nucleus orientation to the product yielded by the reaction. As an example, a simplest fusion reaction between {sub 1}H{sup 2} and {sub 1}H{sup 3} is observed. Several products of the fusion reaction have been obtained, even the unreported ones, including temporary {sub 2}He{sup 4} nucleus.

  8. Studies of Neutron-Deficient Nuclei Near the Z = 82 Shell Closure via Cold Fusion Reactions

    NASA Astrophysics Data System (ADS)

    Carpenter, M. P.; Kondev, F. G.; Janssens, R. V. F.; Seweryniak, D.; Khoo, T. L.; Lauritsen, T.; Lister, C. J.; Zhu, S.; Camera, F.; Bracco, A.; Million, B.; Leoni, S.; Jenkins, D. G.; Wadsworth, R.

    2009-03-01

    Over the last decade, we have performed in-beam experiments using Gammasphere+FMA to measure excited states in proton-rich Au, Hg, Tl and Pb isotopes. In these studies, the use of the FMA is essential in order to differentiate evaporation residues from the large fission background which dominates the reaction cross-section. In addition, we have found that using near-symmetric reactions at bombarding energies near the Coloumb barrier is beneficial in performing these studies. By keeping the bombarding energy low, fission is minimized and the reaction products are concentrated in only a few channels. New results have recently been obtained using the 90Zr+92Mo reaction to study shape co-existence in 181Tl via the lp evaporation channel. In addition, we have measured the total γ-ray energy and multiplicity associated with the surviving compund system, 179Au, following the fusion reaction, 90Zr+89Y.

  9. Measurement of the survival probabilities for hot fusion reactions.

    PubMed

    Yanez, R; Loveland, W; Yao, L; Barrett, J S; Zhu, S; Back, B B; Khoo, T L; Alcorta, M; Albers, M

    2014-04-18

    We have studied the fission-neutron emission competition in highly excited (274)Hs (Z=108) (where the fission barrier is due to shell effects) formed by a hot fusion reaction. Matching cross bombardments ((26)Mg+(248)Cm and (25)Mg+(248)Cm) were used to identify the properties of first chance fission of (274)Hs. A Harding-Farley analysis of the fission neutrons emitted in the (25)Mg,26+(248)Cm was performed to identify the prescission and postscission components of the neutron multiplicities in each system. (Γn/Γt) for the first chance fission of (274)Hs (E*=63  MeV) is 0.89±0.13; i.e., ∼90% of the highly excited nuclei survive. The high value of that survival probability is due to dissipative effects during deexcitation. A proper description of the survival probabilities of excited superheavy nuclei formed in hot fusion reactions requires consideration of both dynamic and static (shell-related) effects. PMID:24785034

  10. Fusion-Fission In The {sup 86}Kr+{sup 238}U Reaction

    SciTech Connect

    Lipoglavsek, M.; Hansen, E. Lindbo; Petrovic, T.; Vencelj, M.; Bark, R. A.; Gueorguieva, E. A.; Lawrie, J. J.; Lieder, E.; Lieder, R.; Mullins, S. M.; Ntshangase, S. S.; Papka, P.

    2008-05-12

    The {sup 86}Kr+{sup 238}U reaction has been studied at krypton beam energies about 30 MeV above the Coulomb barrier. Reaction products were detected by an array of 32 photovoltaic cells coupled to the AFRODITE {gamma}-ray detector array at iThemba LABS. A symmetric fission component has been observed at about 600 MeV total kinetic energy. This could possibly be due to fusion-fission with a cross section of 35{+-}20 mb.

  11. Activation product transport in fusion reactors. [RAPTOR

    SciTech Connect

    Klein, A.C.

    1983-01-01

    Activated corrosion and neutron sputtering products will enter the coolant and/or tritium breeding material of fusion reactor power plants and experiments and cause personnel access problems. Radiation levels around plant components due to these products will cause difficulties with maintenance and repair operations throughout the plant. Similar problems are experienced around fission reactor systems. The determination of the transport of radioactive corrosion and neutron sputtering products through the system is achieved using the computer code RAPTOR. This code calculates the mass transfer of a number of activation products based on the corrosion and sputtering rates through the system, the deposition and release characteristics of various plant components, the neturon flux spectrum, as well as other plant parameters. RAPTOR assembles a system of first order linear differential equations into a matrix equation based upon the reactor system parameters. Included in the transfer matrix are the deposition and erosion coefficients, and the decay and activation data for the various plant nodes and radioactive isotopes. A source vector supplies the corrosion and neutron sputtering source rates. This matrix equation is then solved using a matrix operator technique to give the specific activity distribution of each radioactive species throughout the plant. Once the amount of mass transfer is determined, the photon transport due to the radioactive corrosion and sputtering product sources can be evaluated, and dose rates around the plant components of interest as a function of time can be determined. This method has been used to estimate the radiation hazards around a number of fusion reactor system designs.

  12. Suppression of complete fusion due to breakup in the reactions {sup 10,11}B+{sup 209}Bi

    SciTech Connect

    Gasques, L. R.; Hinde, D. J.; Dasgupta, M.; Mukherjee, A.; Thomas, R. G.

    2009-03-15

    Above-barrier cross sections of fission and {alpha}-active heavy reaction products were measured for the reactions of {sup 10,11}B with {sup 209}Bi. Systematic analysis showed that the fission originates almost exclusively from complete fusion (CF). Existing measurements of above-barrier fusion products for the {sup 30}Si+{sup 186}W reaction, assumed to proceed exclusively through CF, were extrapolated to the current systems using statistical model calculations. This extrapolation showed that the heavy reaction products from the {sup 10,11}B+{sup 209}Bi reactions include substantial components from incomplete fusion as well as from CF. Compared with fusion calculations without breakup, the CF cross sections are suppressed by 15% for {sup 10}B and 7% for {sup 11}B. A consistent and systematic variation of the suppression of CF for reactions of the weakly bound nuclei {sup 6,7}Li, {sup 9}Be, and {sup 10,11}B on targets of {sup 208}Pb and {sup 209}Bi is found as a function of the breakup threshold energy.

  13. The application of diagnostic equipment in the Tokamak fusion reaction

    NASA Astrophysics Data System (ADS)

    Zhang, Bang-shuai; Chang, Jun; Gong, Xian-zu; Gan, Jia-fu; Feng, Shu-long

    2011-11-01

    This paper introduces the infrared optical system in the Tokamak fusion reaction device. In this optical system, the traditional optical structure can't meet the requirements, because the length of the infrared optical system in the Tokamak is very long. The design of optical system in the detection facility includes three parts:1.the combination of the concave aspheric mirror and flat mirror; 2.the Cassegrain system; 3.the relay group lenses. This paper describes the decrease of the modulation transfer function (MTF) when the temperature changes and how to compensate the decrease of the MTF in order to maintain the image quality in a high level. As a result, the image quality of this optical system can reach the requirements when the temperature changes.

  14. Ion transport of Fr nuclear reaction products

    SciTech Connect

    Behr, J.A.; Cahn, S.B.; Dutta, S.B.

    1993-04-01

    Experiments planned for fundamental studies of radioactive atoms in magneto-optic traps require efficient deceleration and transport of nuclear reaction products to energies and locations where they can be trapped. The authors have built a low-energy ion transport system for Francium and other alkalis. A thick Au target is held on a W rod at 45{degrees} to the accelerator beam direction. The heavy-ion fusion reaction 115 MeV {sup 18}O + {sup 197}Au produces {sup 211,210,209}Fr recoil products which are stopped in the target. The target is heated to close to the melting point of Au to allow the Fr to diffuse to the surface, where it is ionized due to Au`s high work function, and is directly extracted by an electrode at 90{degrees} to the accelerator beam direction. The Fr is transported by electrostatic optics {approximately}1 m to a catcher viewed by an {alpha} detector: {ge}15% of the Fr produced in the target reaches the catcher. 2{times}10{sup 5} Fr/sec have been produced at the catcher, yielding at equilibrium a sample of 3x10{sup 7}Fr nuclei. This scheme physically decouples the target diffusion from the surface neutralization process, which can occur at a lower temperature more compatible with the neutral-atom trap.

  15. The fusion-fission process in the reaction 34S +186W near the interaction barrier

    NASA Astrophysics Data System (ADS)

    Harca, I. M.; Dmitriev, S.; Itkis, J.; Kozulin, E. M.; Knyazheva, G.; Loktev, T.; Novikov, K.; Azaiez, F.; Gottardo, A.; Matea, I.; Verney, D.; Chubarian, G.; Hanappe, F.; Piot, J.; Schmitt, C.; Trzaska, W. H.; Vardaci, E.

    2015-02-01

    The reaction 34S +186W at Elab=160 MeV was investigated with the aim of diving into the features of the fusion-fission process. Gamma rays in coincidence with binary reaction fragments were measured using the high efficiency gamma-ray spectrometer ORGAM at the TANDEM Accelerator facility of I.P.N., Orsay, and the time-of-flight spectrometer for fission fragments (FF) registration CORSET of the Flerov Laboratory of Nuclear Reactions (FLNR), Dubna. The coupling of the ORGAM and CORSET setups offers the unique opportunity of extracting details for characterizing the fusion-fission process and gives information regarding production of neutron-rich heavy nuclei. The FF-γ coincidence method is of better use then the γ - γ coincidence method when dealing with low statistic measurements and also offers the opportunity to precisely correct the Dopler shift for in-flight emitted gamma rays. Evidence of symmetric and asymmetric fission modes were observed in the mass and TKE distributions, occurring due to shell effects in the fragments. Coincident measurements allow for discrimination between the gamma rays by accepting a specific range within the mass distribution of the reaction products. Details regarding the experimental setup, methods of processing the acquisitioned data and preliminary results are presented.

  16. Methods of detection using a cellulose binding domain fusion product

    DOEpatents

    Shoseyov, Oded; Shpiegl, Itai; Goldstein, Marc A.; Doi, Roy H.

    1999-01-01

    A cellulose binding domain (CBD) having a high affinity for crystalline cellulose and chitin is disclosed, along with methods for the molecular cloning and recombinant production thereof. Fusion products comprising the CBD and a second protein are likewise described. A wide range of applications are contemplated for both the CBD and the fusion products, including drug delivery, affinity separations, and diagnostic techniques.

  17. Methods of detection using a cellulose binding domain fusion product

    DOEpatents

    Shoseyov, O.; Shpiegl, I.; Goldstein, M.A.; Doi, R.H.

    1999-01-05

    A cellulose binding domain (CBD) having a high affinity for crystalline cellulose and chitin is disclosed, along with methods for the molecular cloning and recombinant production. Fusion products comprising the CBD and a second protein are likewise described. A wide range of applications are contemplated for both the CBD and the fusion products, including drug delivery, affinity separations, and diagnostic techniques. 34 figs.

  18. Reaction products of chlorine dioxide.

    PubMed Central

    Stevens, A A

    1982-01-01

    Inspection of the available literature reveals that a detailed investigation of the aqueous organic chemistry of chlorine dioxide and systematic identification of products formed during water disinfection has not been considered. This must be done before an informed assessment can be made of the relative safety of using chlorine dioxide as a disinfectant alternative to chlorine. Although trihalomethanes are generally not formed by the action of chlorine dioxide, the products of chlorine dioxide treatment of organic materials are oxidized species, some of which also contain chlorine. The relative amounts of species types may depend on the amount of chlorine dioxide residual maintained and the concentration and nature of the organic material present in the source water. The trend toward lower concentrations of chlorinated by-products with increasing ClO2 concentration, which was observed with phenols, has not been observed with natural humic materials as measured by the organic halogen parameter. Organic halogen concentrations have been shown to increase with increasing chlorine dioxide dose, but are much lower than those observed when chlorine is applied. Aldehydes have been detected as apparent by-products of chlorine dioxide oxidation reactions in a surface water that is a drinking water source. Some other nonchlorinated products of chlorine dioxide treatment may be quinones and epoxides. The extent of formation of these moieties within the macromolecular humic structure is also still unknown. PMID:7151750

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

    SciTech Connect

    Fotiadis, Nikolaos; Nelson, Ronald O; Devlin, Matthew; Cizewski, Jolie A; Krucken, Reiner; Clark, R M; Fallon, Paul; Lee, I Yang; Macchiavelli, Agusto O; Becker, John A; Younes, Walid

    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 states between the neutron-deficient and neutron-rich nuclei. Results near shell closures should motivate new shell model calculations.

  20. RF heating for fusion product studies

    NASA Astrophysics Data System (ADS)

    Hellsten, T.; Johnson, T.; Sharapov, S. E.; Kiptily, V.; Eriksson, J.; Mantsinen, M.; Schneider, M.; Rimini, F.; Tsalas, M.

    2015-12-01

    Third harmonic cyclotron heating is an effective tool for accelerating deuterium (D) beams to the MeV energy range, suitable for studying ITER relevant fast particle physics in plasmas without significant tritium content. Such experiments were recently conducted in JET with an ITER like wall in D plasmas with 3He concentrations up to 30% in order to boost the fusion reactivity by D-3He reactions. The harmonic cyclotron heating produces high-energy tails in the MeV range of D ions by on-axis heating and of 3He ions by tangential off-axis heating. The discharges are characterized by long sawtooth free periods and a rich spectrum of MHD modes excited by the fast D and 3He ions. The partitions of the power, which depend on the distribution function of D, vary strongly over several slowing down times. Self-consistent modelling of the distribution function with the SELFO-light code are presented and compared with experimental data from fast particle diagnostics.

  1. RF heating for fusion product studies

    SciTech Connect

    Hellsten, T. Johnson, T.; Sharapov, S. E.; Kiptily, V.; Rimini, F.; Eriksson, J.; Mantsinen, M.; Schneider, M.; Tsalas, M.

    2015-12-10

    Third harmonic cyclotron heating is an effective tool for accelerating deuterium (D) beams to the MeV energy range, suitable for studying ITER relevant fast particle physics in plasmas without significant tritium content. Such experiments were recently conducted in JET with an ITER like wall in D plasmas with {sup 3}He concentrations up to 30% in order to boost the fusion reactivity by D-{sup 3}He reactions. The harmonic cyclotron heating produces high-energy tails in the MeV range of D ions by on-axis heating and of {sup 3}He ions by tangential off-axis heating. The discharges are characterized by long sawtooth free periods and a rich spectrum of MHD modes excited by the fast D and {sup 3}He ions. The partitions of the power, which depend on the distribution function of D, vary strongly over several slowing down times. Self-consistent modelling of the distribution function with the SELFO-light code are presented and compared with experimental data from fast particle diagnostics.

  2. Inertial confinement fusion reaction chamber and power conversion system study. Final report

    SciTech Connect

    Maya, I.; Schultz, K.R.; Bourque, R.F.; Cheng, E.T.; Creedon, R.L.; Norman, J.H.; Price, R.J.; Porter, J.; Schuster, H.L.; Simnad, M.J.

    1985-10-01

    This report summarizes the results of the second year of a two-year study on the design and evaluation of the Cascade concept as a commercial inertial confinement fusion (ICF) reactor. We developed a reactor design based on the Cascade reaction chamber concept that would be competitive in terms of both capital and operating costs, safe and environmentally acceptable in terms of hazard to the public, occupational exposure and radioactive waste production, and highly efficient. The Cascade reaction chamber is a double-cone-shaped rotating drum. The granulated solid blanket materials inside the rotating chamber are held against the walls by centrifugal force. The fusion energy is captured in a blanket of solid carbon, BeO, and LiAlO/sub 2/ granules. These granules are circulated to the primary side of a ceramic heat exchanger. Primary-side granule temperatures range from 1285 K at the LiAlO/sub 2/ granule heat exchanger outlet to 1600 K at the carbon granule heat exchanger inlet. The secondary side consists of a closed-cycle gas turbine power conversion system with helium working fluid, operating at 1300 K peak outlet temperature and achieving a thermal power conversion efficiency of 55%. The net plant efficiency is 49%. The reference design is a plant producing 1500 MW of D-T fusion power and delivering 815 MW of electrical power for sale to the utility grid. 88 refs., 44 figs., 47 tabs.

  3. Fusion Reactions of Superheavy and Giant Nuclear Systems

    SciTech Connect

    Greiner, Walter; Zagrebaev, Valery

    2007-05-22

    The problem of production and study of superheavy elements is discussed in the talk. Different nuclear reactions leading to formation of superheavy nuclei are analyzed. Collisions of transactinide nuclei are investigated as an alternative way for production of neutron-rich superheavy elements. In many events lifetime of the composite giant nuclear system consisting of two touching nuclei turns out to be rather long ({>=} 10-20 s); sufficient for observing line structure in spontaneous positron emission from super-strong electric fields, a fundamental QED process.

  4. Effects of magnetization on fusion product trapping and secondary neutron spectra

    SciTech Connect

    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.; and others

    2015-05-15

    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.

  5. Effects of magnetization on fusion product trapping and secondary neutron spectra

    SciTech Connect

    Knapp, Patrick F.; Schmit, Paul F.; Hansen, Stephanie B.; Gomez, Matthew R.; Hahn, Kelly D.; Sinars, Daniel Brian; Peterson, Kyle J.; Slutz, Stephen A.; Sefkow, Adam B.; Awe, Thomas James; Harding, Eric; Jennings, Christopher A.; Desjarlais, M. P.; Chandler, Gordon A.; Cooper, Gary Wayne; Cuneo, Michael Edward; Geissel, Matthias; Harvey-Thompson, Adam James; Porter, John L.; Rochau, Gregory A.; Rovang, Dean C.; Ruiz, Carlos L.; Savage, Mark E.; Smith, Ian C.; Stygar, William A.; Herrmann, Mark

    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 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 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.

  6. Effects of magnetization on fusion product trapping and secondary neutron spectra

    DOE PAGESBeta

    Knapp, Patrick F.; Schmit, Paul F.; Hansen, Stephanie B.; Gomez, Matthew R.; Hahn, Kelly D.; Sinars, Daniel Brian; Peterson, Kyle J.; Slutz, Stephen A.; Sefkow, Adam B.; Awe, Thomas James; et al

    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

  7. 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.

  8. Production of unknown transactinides in asymmetry-exit-channel quasifission reactions

    SciTech Connect

    Adamian, G.G.; Antonenko, N. V.; Zubov, A. S.

    2005-03-01

    Possibilities of production of new isotopes of superheavy nuclei with charge numbers 104-108 in asymmetry-exit-channel quasifission reactions are studied for the first time. The optimal conditions for the synthesis are suggested in this type of reaction. The products of suggested reactions can fill a gap of unknown isotopes between the isotopes of heaviest nuclei obtained in cold and hot complete fusion reactions.

  9. Applications of Skyrme energy-density functional to fusion reactions for synthesis of superheavy nuclei

    SciTech Connect

    Wang Ning; Scheid, Werner; Wu Xizhen; Liu Min; Li Zhuxia

    2006-10-15

    The Skyrme energy-density functional approach has been extended to study massive heavy-ion fusion reactions. Based on the potential barrier obtained and the parametrized barrier distribution the fusion (capture) excitation functions of a lot of heavy-ion fusion reactions are studied systematically. The average deviations of fusion cross sections at energies near and above the barriers from experimental data are less than 0.05 for 92% of 76 fusion reactions with Z{sub 1}Z{sub 2}<1200. For the massive fusion reactions, for example, the {sup 238}U-induced reactions and {sup 48}Ca+{sup 208}Pb, the capture excitation functions have been reproduced remarkably well. The influence of structure effects in the reaction partners on the capture cross sections is studied with our parametrized barrier distribution. By comparing the reactions induced by double-magic nucleus {sup 48}Ca and by {sup 32}S and {sup 35}Cl, the ''threshold-like'' behavior in the capture excitation function for {sup 48}Ca-induced reactions is explored and an optimal balance between the capture cross section and the excitation energy of the compound nucleus is studied. Finally, the fusion reactions with {sup 36}S, {sup 37}Cl, {sup 48}Ca, and {sup 50}Ti bombarding {sup 248}Cm, {sup 247,249}Bk, {sup 250,252,254}Cf, and {sup 252,254}Es, as well as the reactions leading to the same compound nucleus with Z=120 and N=182, are studied further. The calculation results for these reactions are useful for searching for the optimal fusion configuration and suitable incident energy in the synthesis of superheavy nuclei.

  10. Calculations of Proton Emission Cross Sections in Deuteron Induced Reactions of Some Fusion Structural Materials

    NASA Astrophysics Data System (ADS)

    Yiğit, M.; Tel, E.; Tanır, G.

    2013-06-01

    The growing demands for energy consumption have led to the increase of the research and development activities on new energy sources. Fusion energy has the highest potential to become a very safe, clean and abundant energy source for the future. To get energy from fusion are needed for development of fusion reactor technology. Particularly, the design and development of international facilities as International Thermonuclear Experimental Reactor and International Fusion Material Irradiation Facility requires for the cross-section data of deuteron induced reactions. Moreover, the selection of fusion structural materials are an indispensable component for this technology. Therefore, the cross-section data of deuteron induced reactions on fusion structural materials are of great importance for development of fusion reactor technology. In this study, reaction model calculations of the cross sections of deuteron induced reactions on structural fusion materials such as 27Al, 59Co, 55Mn, 50Cr, 54Cr, 64Ni, 109Ag, 184W and 186W have been carried out for incident energies up to 50 MeV. In these calculations, the pre-equilibrium and equilibrium effects for ( d, p) stripping reactions have been investigated. The pre-equilibrium calculations involve the new evaluated the geometry dependent hybrid model and hybrid model. Equilibrium effects are calculated according to the Weisskopf-Ewing model. In the calculations the program code ALICE/ASH was used. The calculated results are discussed and compared with the experimental data taken from the literature.

  11. HYPERFUSE: a hypervelocity inertial confinement system for fusion energy production and fission waste transmutation

    SciTech Connect

    Makowitz, H; Powell, J R; Wiswall, R

    1980-01-01

    Parametric system studies of an inertial confinement fusion (ICF) reactor system to transmute fission products from an LWR economy have been carried out. The ICF reactors would produce net power in addition to transmuting fission products. The particular ICF concept examined is an impact fusion approach termed HYPERFUSE, in which hypervelocity pellets, traveling on the order of 100 to 300 km/sec, collide with each other or a target block in a reactor chamber and initiate a thermonuclear reaction. The DT fusion fuel is contained in a shell of the material to be transmuted, e.g., /sup 137/Cs, /sup 90/Sr, /sup 129/I, /sup 99/Tc, etc. The 14-MeV fusion neutrons released during the pellet burn cause transmutation reactions (e.g., (n,2n), (n,..cap alpha..), (n,..gamma..), etc.) that convert the long-lived fission products (FP's) either to stable products or to species that decay with a short half-life to a stable product. The transmutation parametric studies conclude that the design of the hypervelocity projectiles should emphasize the achievement of high densities in the transmutation regions (greater than the DT fusion fuel density), as well as the DT ignition and burn criterion (rho R=1.0 to 3.0) requirements.

  12. Possibilities for synthesis of new isotopes of superheavy nuclei in cold fusion reactions

    NASA Astrophysics Data System (ADS)

    Bao, X. J.; Gao, Y.; Li, J. Q.; Zhang, H. F.

    2016-04-01

    In order to find a way to produce superheavy nuclei (SHN), which appear in the gap between the SHN synthesized by cold fusion and those by hot fusion, or those so far not yet been produced in the laboratory, we tried to make use of a set of projectile isotopic chains, to use a radioactive beam projectile, and to test symmetric fusion reactions for gaining more neutrons to synthesize neutron-richer SHN based on the dinuclear system (DNS) model via cold fusion reactions. It is found that the nuclei 265Mt,Ds,272268,273Rg, and 274,275,276Cn may be produced with the detectable evaporation residual cross sections. The intensities of radioactive beams are significantly less than those of the stable beams, therefore using a stable beam is predicted to be the most favorable method for producing SHN. From the symmetric reaction system 136Xe+136Xe , no fusion event was found.

  13. 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 Central

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

    2015-01-01

    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. PMID:25655701

  14. A charged fusion product diagnostic for a spherical tokamak

    NASA Astrophysics Data System (ADS)

    Perez, Ramona Leticia Valenzuela

    Designs for future nuclear fusion power reactors rely on the ability to create a stable plasma (hot ionized gas of hydrogen isotopes) as a medium with which to sustain nuclear fusion reactions. My dissertation work involves designing, constructing, testing, installing, operating, and validating a new diagnostic for spherical tokamaks, a type of reactor test facility. Through detecting charged particles emitted from the plasma, this instrument can be used to study fusion reaction rates within the plasma and how they are affected by plasma perturbations. Quantitatively assessing nuclear fusion reaction rates at specific locations inside the plasma and as a function of time can provide valuable data that can be used to evaluate theory-based simulations related to energy transport and plasma stability. The Proton Detector (PD), installed in the Mega Amp Spherical Tokamak (MAST) at the Culham Centre for Fusion Energy (CCFE) in Abingdon, England, was the first instrument to experimentally detect 3 MeV Protons and 1 MeV Tritons created from deuterium- deuterium (hydrogen isotopes) nuclear fusion reactions inside a spherical tokamak's plasma. The PD consists of an array of particle detectors with a protective housing and the necessary signal conditioning electronics and readout. After several years of designing (which included simulations for detector orientations), fabricating, and testing the PD, it was installed in MAST and data were collected over a period of two months in the summer of 2013. Proton and triton rates as high as 200 kHz were measured and an initial radial profile of these fusion reaction rates inside the plasma was extracted. These results will be compared to a complementary instrument at MAST as well as theory-based simulations and form the knowledge basis for developing a larger future instrument. The design and performance of all instrument components (electrical, computational, mechanical), and subsequent data analysis methods and results are

  15. Charge-exchange and fusion reaction measurements during compression experiments with neutral beam heating in the Tokamak Fusion Test Reactor

    SciTech Connect

    Kaita, R.; Heidbrink, W.W.; Hammett, G.W.; Chan, A.A.; England, A.C.; Hendel, H.W.; Medley, S.S.; Nieschmidt, E.; Roquemore, A.L.; Scott, S.D.

    1986-04-01

    Adiabatic toroidal compression experiments were performed in conjunction with high power neutral beam injection in the Tokamak Fusion Test Reactor (TFTR). Acceleration of beam ions to energies nearly twice the injection energy was measured with a charge-exchange neutral particle analyzer. Measurements were also made of 2.5 MeV neutrons and 15 MeV protons produced in fusion reactions between the deuterium beam ions and the thermal deuterium and /sup 3/He ions, respectively. When the plasma was compressed, the d(d,n)/sup 3/He fusion reaction rate increased a factor of five, and the /sup 3/He(d,p)/sup 4/He rate by a factor of twenty. These data were simulated with a bounce-averaged Fokker-Planck program, which assumed conservation of angular momentum and magnetic moment during compression. The results indicate that the beam ion acceleration was consistent with adiabatic scaling.

  16. Hot fusion-evaporation cross sections of 45Sc -induced reactions with lanthanide targets

    NASA Astrophysics Data System (ADS)

    Werke, T. A.; Mayorov, D. A.; Alfonso, M. C.; Bennett, M. E.; DeVanzo, M. J.; Frey, M. M.; Tereshatov, E. E.; Folden, C. M.

    2015-09-01

    Background: 45Sc has rarely been studied as a projectile in fusion-evaporation reactions. The synthesis of new superheavy elements with Z >118 will require projectiles with Z >20 , and 45Sc could potentially be used for this purpose. Purpose: Cross sections were measured for the x n and p x n exit channels in the reactions of 45Sc with lanthanide targets for comparison to previous measurements of 48Ca reacting with similar targets. These data provide insight on the survival of spherical, shell-stabilized nuclei against fission, and could have implications for the discovery of new superheavy elements. Methods: Beams of 45Sc6 + were delivered from the K500 superconducting cyclotron at Texas A&M University with an energy of ≈5 MeV /nucleon . Products were purified using the Momentum Achromat Recoil Spectrometer, and excitation functions were measured for reactions of 45Sc+156-158,160Gd, 159Tb , and 162Dy at five or more energies each. Evaporation residues were identified by their characteristic α -decay energies. Experimental data were compared to a simple theoretical model to study each step in the fusion-evaporation process. Results: The maximum measured 4 n cross sections for the reactions 45Sc+156-158,160Gd, 159Tb , and 162Dy are 5.8 ±1.7 , 25 ±5 , 39 ±7 , 150 ±20 , 2 .4-1.4+2.3 , and 1.8 ±0.6 μ b , respectively. Proton emission competes effectively with neutron emission from the excited compound nucleus in most cases. The α ,α n , and α 2 n products were also observed in the 45Sc+162Dy reaction. Conclusions: Excitation functions were reported for 45Sc -induced reactions on lanthanide targets for the first time, and these cross sections are much smaller than for 48Ca -induced reactions on the same targets. The relative neutron-deficiency of the compound nuclei leads to significantly increased fissility and large reductions in the survival probability. Little evidence for improved production cross sections due to shell-stabilization was observed.

  17. Attempt to produce the isotopes of element 108 in the fusion reaction {sup 136}Xe+{sup 136}Xe

    SciTech Connect

    Oganessian, Yu. Ts.; Dmitriev, S. N.; Yeremin, A. V.; Aksenov, N. V.; Bozhikov, G. A.; Chepigin, V. I.; Chelnokov, M. L.; Lebedev, V. Ya.; Malyshev, O. N.; Petrushkin, O. V.; Shishkin, S. V.; Svirikhin, A. I.; Tereshatov, E. E.; Vostokin, G. K.

    2009-02-15

    A setup of the experiment on the production of the isotopes with Z=108 in the fusion reaction {sup 136}Xe+{sup 136}Xe and the obtained results are presented. At the excitation energy 0{<=}E{sub x}{<=}30 MeV of the {sup 272}Hs* compound nucleus the upper limit of the cross section for evaporation residues {sigma}{sub (1-3)n}{<=}4 pb has been measured. The experimental results together with the data from asymmetric reactions point to a strong limitation of the Hs compound nucleus formation with increasing Coulomb forces in the entrance channel of the reaction.

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

    NASA Astrophysics Data System (ADS)

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

    2013-10-01

    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.

  19. 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. PMID:24104859

  20. Role of neutron transfer in asymmetric fusion reactions at sub-barrier energies

    NASA Astrophysics Data System (ADS)

    Ogloblin, A. A.; Zhang, H. Q.; Lin, C. J.; Jia, H. M.; Khlebnikov, S. V.; Kuzmin, E. A.; Trzaska, W. H.; Xu, X. X.; Yan, F.; Sargsyan, V. V.; Adamian, G. G.; Antonenko, N. V.; Scheid, W.

    2014-10-01

    The measured complete fusion (capture) excitation function is presented for the 28Si + 208Pb reaction at deep sub-barrier energies. This excitation function is compared with the one predicted with the quantum diffusion approach.

  1. 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.

  2. Analysis of the role of neutron transfer in asymmetric fusion reactions at subbarrier energies

    NASA Astrophysics Data System (ADS)

    Ogloblin, A. A.; Zhang, H. Q.; Lin, C. J.; Jia, H. M.; Khlebnikov, S. V.; Kuzmin, E. A.; Danilov, A. N.; Demyanova, A. S.; Trzaska, W. H.; Xu, X. X.; Yang, F.; Sargsyan, V. V.; Adamian, G. G.; Antonenko, N. V.; Scheid, W.

    2015-12-01

    The excitation functions were measured for the 28Si + 208Pb complete-fusion (capture) reaction at deep subbarrier energies. The results were compared with the cross sections predicted within the quantum diffusion approach. The role of neutron transfer in the case of positive Q values in the 28Si + 124Sn, 208Pb; 30Si + 124Sn, 208Pb; 20Ne + 208Pb; 40Ca + 96Zr; and 134Te + 40Ca complete-fusion (capture) reactions is discussed.

  3. Competition between complete fusion and quasifission in reactions with heavy nuclei

    SciTech Connect

    Antonenko, N. V.; Scheid, W.; Adamian, G. G.; Volkov, V. V.

    1998-02-15

    A model based on the dinuclear system concept is suggested for the calculation of the competition between complete fusion and quasifission in reactions with heavy nuclei. The fusion rate through the inner fusion barrier in mass asymmetry is found by using the Kramers-type expression. The calculated cross sections for the heaviest nuclei are in a good agreement with the experimental data. The experimentally observed rapid fall-off of the cross section of the cold fusion with increasing charge number Z of the compound nucleus is explained.

  4. Measurements of fusion reactions of low-intensity radioactive carbon beams on 12C and their implications for the understanding of X-ray bursts.

    PubMed

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

    2014-05-16

    The interaction between neutron-rich nuclei plays an important role for understanding the reaction mechanism of the fusion process as well as for the energy production through pycnonuclear reactions in the crust of neutron stars. We have performed the first measurements of the total fusion cross sections in the systems (10,14,15)C+(12)C using a new active target-detector system. In the energy region accessible with existing radioactive beams, a good agreement between the experimental and theoretical cross sections is observed. This gives confidence in our ability to calculate fusion cross sections for systems which are outside the range of today's radioactive beam facilities. PMID:24877935

  5. ConnesFusionTensorProduct/Photon GluonFusion in Mitochondria

    NASA Astrophysics Data System (ADS)

    Wh-Maksoed, Prodi Of Physics Ui, Depok 16415-Indonesia; Ssi, Wh-Maksoed

    2016-05-01

    As in AJ Wassermann distinguished of classical invariant theory & quantum invariant theory subfactor, in S. Palcoux:``From Neveu-Schwarz Subfactors & Connes Fusion'' described the subfactor theory & Witt-algebra whereas Andreas Thom's explanation about ConnesFusionTensorProduct/CFTP related Connes fusion to composition of homomorphism (i). classical tensor product O-X adds the changes,(ii). Relative tensor product H-X preserve the changes. For photonGluonFusion/PGF defined:''photon is the gauge boson of QED, the simplest of all boson'' devotes to CFT as ``quantum field theory which are invariant under conformal transformation & in 2D there are infinite dimensional algebra. Alain Connes states theirselves Connes fusion as ``associative tensor operation'' to be in coincidences with ``their dynamic behavior driven by the balance in mitochondrial fusion & fission (Carveney, 2007) from Peter Alexander Williams: ``Retinal neuronal remodeling in a model of Optic Atrophy'', Dec, 2011. Great acknowledged to the VicePresident of the R.I, HE.Mr. Drs. M. JUSUF KALLA.

  6. Fusion-neutron production in the TFTR with deuterium neutral beam injection

    SciTech Connect

    Hendel, H.W.; England, A.C.; Jassby, D.L.; Mirin, A.A.; Nieschmidt, E.B.

    1986-06-01

    We report measurements of the fusion reaction rate in the Tokamak Fusion Test Reactor (TFTR) covering a wide range of plasma conditions and injected neutral beam powers up to 6.3 MW. The fusion-neutron production rate in beam-injected plasmas decreases slightly with increasing plasma density n/sub e/, even though the energy confinement parameter n/sub e/tau/sub E/ generally increases with density. The measurements indicate and Fokker-Planck simulations show that with increasing density the source of fusion neutrons evolves from mainly beam-beam and beam-target reactions at very low n/sub e/ to a combination of beam-target and thermonuclear reactions at high n/sub e/. At a given plasma current, the reduction in neutron source strength at higher n/sub e/ is due to both a decrease in electron temperature and in beam-beam reaction rate. The Fokker-Planck simulations also show that at low n/sub e/, plasma rotation can appreciably reduce the beam-target reaction rate for experiments with co-injection only. The variation of neutron source strength with plasma and beam parameters is as expected for beam-dominated regimes. However, the Fokker-Planck simulations systematically overestimate the measured source strength by a factor of 2 to 3; the source of this discrepancy has not yet been identified.

  7. Capture and Fusion-Fission Processes in Heavy Ion Induced Reactions

    NASA Astrophysics Data System (ADS)

    Itkis, M. G.; Beghini, S.; Behera, B. R.; Bogatchev, A. A.; Bouchat, V.; Corradi, L.; Dorvaux, O.; Fioretto, E.; Gadea, A.; Hanappe, F.; Itkis, I. M.; Jandel, M.; Kliman, J.; Knyazheva, G. N.; Kondratiev, N. A.; Kozulin, E. M.; Krupa, L.; Latina, A.; Lyapin, V. G.; Materna, T.; Montagnoli, G.; Oganessian, Yu. Ts.; Pokrovsky, I. V.; Prokhorova, E. V.; Rowley, N.; Rubchenya, V. A.; Rusanov, A. Ya.; Sagaidak, R. N.; Scarlassara, F.; Schmitt, C.; Stefanini, A. M.; Stuttge, L.; Szilner, S.; Trotta, M.; Trzaska, W. H.; Voskresenski, V. M.

    2005-11-01

    Results of the experiments aimed at the study of fission and quasi-fission processes in the reactions 12C+204Pb, 48Ca+144,154Sm, 168Er, 208Pb, 238U, 244Pu, 248Cm; 58Fe+208Pb, 244Pu, 248Cm, and 64Ni+186W, 242Pu are presented. The choice of the above-mentioned reactions was inspired by the experiments on the production of the isotopes 283112, 289114 and 283116 at Dubna using the same reactions. The 58Fe and 64Ni projectiles were chosen since the corresponding projectile-target combinations lead to the synthesis of even heavier elements. The experiments were carried out at the U-400 accelerator of the Flerov Laboratory of Nuclear Reactions (JINR, Russia), the XTU Tandem accelerator of the National Laboratory of Legnaro (LNL, Italy) and the Accelerator of the Laboratory of University of Jyvaskyla (JYFL, Finland) using the time-of-flight spectrometer of fission fragments CORSET and the neutron multi-detector DEMON. The role of shell effects and the influence of the entrance channel asymmetry and the deformations of colliding nucleus on the mechanism of the fusion-fission and the competitive process of quasi-fission are discussed.

  8. HYPERFUSE: a hypervelocity inertial confinement system for fusion energy production and fission waste transmutation

    SciTech Connect

    Makowitz, H.; Powell, J.R.; Wiswall, R.

    1980-01-01

    Parametric system studies of an inertial confinement fusion (ICF) reactor system to transmute fission products from a LWR economy have been carried out. The ICF reactors would produce net power in addition to transmuting fission products. The particular ICF concept examined is an impact fusion approach termed HYPERFUSE, in which hypervelocity pellets, traveling on the order of 100 to 300 km/sec, collide with each other or a target block in a reactor chamber and initiate a thermonuclear reaction. The DT fusion fuel is contained in a shell of the material to be transmuted, e.g., /sup 137/Cs, /sup 90/Sr, /sup 129/I, /sup 99/Tc, etc. The 14-MeV fusion neutrons released during the pellet burn cause transmutation reactions (e.g., (n,2n), (n,..cap alpha..), (n,..gamma..), etc.) that convert the long-lived fission products (FP's) either to stable products or to species that decay with a short half-life to a stable product. The transmutation parametric studies conclude that the design of the hypervelocity projectiles should emphasize the achievement of high densities in the transmutation regions (greater than the DT fusion fuel density), as well as the DT ignition and burn criterion (rho R = 1.0 to 3.0) requirements. These studies also indicate that masses on the order of 1.0 g at densities of rho greater than or equal to 500.0 g/cm/sup 3/ are required for a practical fusion-based fission product transmutation system.

  9. Complete and Incomplete Fusion Competition in 11B-INDUCED Fission Reactions on 197Au at the Intermediate Energy

    NASA Astrophysics Data System (ADS)

    Demekhina, N. A.; Karapetyan, G. S.; Balabekyan, A. R.

    2015-06-01

    Above Coulomb barrier cross sections of fission fragment production were measured in reactions of 11B with 197Au target. Induced-activity method was used for measurement the fission decay channel of the composite nuclei. Systematic of the fission fragment charge and mass distributions was used for fission cross section calculation. Fission fraction of the composite nuclei decay was compared with PACE-4 mode calculations. Estimated suppression for fission fraction followed the complete fusion have been obtained 35%.

  10. Quasifission and fusion-fission in reactions with massive nuclei: Comparison of reactions leading to the Z=120 element

    SciTech Connect

    Nasirov, A. K.; Giardina, G.; Mandaglio, G.; Manganaro, M.; Hanappe, F.; Heinz, S.; Hofmann, S.; Muminov, A. I.; Scheid, W.

    2009-02-15

    The yields of evaporation residues, fusion-fission, and quasifission fragments in the {sup 48}Ca+{sup 144,154}Sm and {sup 16}O+{sup 186}W reactions are analyzed in the framework of the combined theoretical method based on the dinuclear system concept and advanced statistical model. The measured yields of evaporation residues for the {sup 48}Ca+{sup 154}Sm reaction can be well reproduced. The measured yields of fission fragments are decomposed into contributions coming from fusion-fission, quasifission, and fast-fission. The decrease in the measured yield of quasifission fragments in {sup 48}Ca+{sup 154}Sm at the large collision energies and the lack of quasifission fragments in the {sup 48}Ca+{sup 144}Sm reaction are explained by the overlap in mass angle distributions of the quasifission and fusion-fission fragments. The investigation of the optimal conditions for the synthesis of the new element Z=120 (A=302) show that the {sup 54}Cr+{sup 248}Cm reaction is preferable in comparison with the {sup 58}Fe+{sup 244}Pu and {sup 64}Ni+{sup 238}U reactions because the excitation function of the evaporation residues of the former reaction is some orders of magnitude larger than that for the last two reactions.

  11. Study of fusion-fission dynamics in 19F+238U reaction

    NASA Astrophysics Data System (ADS)

    Dubey, R.; Sugathan, P.; Jhingan, A.; Kaur, Gurpreet; Mukul, Ish; Siwal, Davinder; Saneesh, N.; Banerjee, Tathagata; Yadav, Abhishek; Thakur, Meenu; Mahajan, Ruchi; Chaterjee, M. B.

    2016-05-01

    Mass angle distribution measurements for 19F+238U reaction were carried out around the sub barrier energies. Mass angle correlation has not been observed at above and below the fusion barrier in present reaction. This infer the minimal presence of non compound like events at these bombarding energies range.

  12. No-capture breakup and incomplete fusion reactions induced by stable weakly bound nucleus 9Be

    NASA Astrophysics Data System (ADS)

    Seyyedi, S. A.

    2016-06-01

    The reactions including the stable weakly bound nucleus 9Be have been studied using the classical trajectory model accompanied with the experimental breakup function and the Aage-Winther interaction potential (AW95). In these calculations, the no-capture breakup and the incomplete fusion cross-sections as well as their competition at around the Coulomb barrier have been investigated. Our calculations showed that at a given far-Coulomb-barrier energy the incomplete fusion reaction in different distributions of angular momentum and energies can dominate the no-capture breakup reaction. This dominating process is reversed at the near-barrier energies.

  13. Recent developments in heavy-ion fusion reactions around the Coulomb barrier

    NASA Astrophysics Data System (ADS)

    Hagino, K.; Rowley, N.; Yao, J. M.

    2016-06-01

    The nuclear fusion is a reaction to form a compound nucleus. It plays an important role in several circumstances in nuclear physics as well as in nuclear astrophysics, such as synthesis of superheavy elements and nucleosynthesis in stars. Here we discuss two recent theoretical developments in heavy-ion fusion reactions at energies around the Coulomb barrier. The first topic is a generalization of the Wong formula for fusion cross sections in a single-channel problem. By introducing an energy dependence to the barrier parameters, we show that the generalized formula leads to results practically indistinguishable from a full quantal calculation, even for light symmetric systems such as 12C+12C, for which fusion cross sections show an oscillatory behavior. We then discuss a semi-microscopic modeling of heavy-ion fusion reactions, which combine the coupled-channels approach to the state-of-the-art nuclear structure calculations for low-lying collective motions. We apply this method to subbarrier fusion reactions of 58Ni+58Ni and 40Ca+58Ni systems, and discuss the role of anharmonicity of the low-lying vibrational motions.

  14. 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.

  15. Revised analysis of 40Ca+96Zr fusion reactions

    NASA Astrophysics Data System (ADS)

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

    2016-03-01

    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. The scaling of the transfer strengths is supposed to simulate the combined effect of neutron and proton transfer, and the calculated one- and two-nucleon transfer cross sections are indeed in reasonable agreement with the measured cross sections.

  16. Role of the neck degree of freedom in cold fusion reactions

    NASA Astrophysics Data System (ADS)

    Adamian, G. G.; Antonenko, N. V.; Lenske, H.

    2015-05-01

    Mass parameters for collective variables of dinuclear systems formed in cold fusion reactions are microscopically calculated with the linear response theory making use of the width of single-particle states and the fluctuation-dissipation theorem. The single-particle spectrum and potential energy surface of the adiabatic two-center shell model are used. The microscopical mass parameter in the neck is found to be much larger than one obtained with the hydrodynamical model. Therefore, the dinuclear system lives a rather long time, comparable to the characteristic time of fusion and, correspondingly, the fusion can be considered at fixed neck parameter. With an adiabatic melting of the dinuclear system along the internuclear distance into a compound system one cannot explain the experimental trends in cold fusion reactions.

  17. Investigating multichannel quantum tunneling in heavy-ion fusion reactions with Bayesian spectral deconvolution

    NASA Astrophysics Data System (ADS)

    Hagino, K.

    2016-06-01

    Excitations of colliding nuclei during a nuclear reaction considerably affect fusion cross sections at energies around the Coulomb barrier. It has been demonstrated that such channel coupling effects can be represented in terms of a distribution of multiple fusion barriers. I here apply a Bayesian approach to analyze the so-called fusion barrier distributions. This method determines simultaneously the barrier parameters and the number of barriers. I particularly investigate the 16O+144Sm and 16O+154Sm systems in order to demonstrate the effectiveness of the method. The present analysis indicates that the fusion barrier distribution for the former system is most consistent with three fusion barriers, even though the experimental data show only two distinct peaks.

  18. Sub- and near-barrier fusion reactions experimental results

    NASA Astrophysics Data System (ADS)

    Montagnoli, G.

    2016-05-01

    Early data of sub-barrier fusion teached us that cross sections may strongly depend on the structure of colliding nuclei and on couplings to transfer channels. The influence of transfer is clearly indicated in the excitation functions of different nickel isotopes and various Ca+Zr systems. Fusion barrier distributions often yield the fingerprint of the relevant inelastic and transfer couplings. At lower energies, far below the barrier the slope of the excitation function keeps increasing in many cases, so that the cross sections are strongly over-predicted by standard coupled-channels (CC) calculations; this was named a hindrance effect. Furthermore, light heavy-ion systems show cross section oscillations above the Coulomb barrier. Recent experiments have been performed on the fusion of 28,30Si+28,30Si systems where all phenomena cited above show up. In particular regular oscillations that have been revealed above the barrier for 28Si+28Si and have been interpreted as the consequence of the strong channel couplings and/or the oblate deformation of 28Si.

  19. Proliferation Risks of Fusion Energy: Clandestine Production, Covert Production, and Breakout

    SciTech Connect

    R.J. Goldston, A. Glaser, A.F. Ross

    2009-08-13

    Nuclear proliferation risks from fusion associated with access to weapon-usable material can be divided into three main categories: 1) clandestine production of fissile material in an undeclared facility, 2) covert production of such material in a declared and safeguarded facility, and 3) use of a declared facility in a breakout scenario, in which a state begins production of fissile material without concealing the effort. In this paper we address each of these categories of risk from fusion. For each case, we find that the proliferation risk from fusion systems can be much lower than the equivalent risk from fission systems, if commercial fusion systems are designed to accommodate appropriate safeguards.

  20. Dispersion relation approach to sub-barrier heavy-ion fusion reactions

    SciTech Connect

    Franzin, V.L.M.; Hussein, M.S.

    1988-11-01

    We discuss the conditions under which the dispersion relation technique, extensively employed in the context of elastic scattering, can be used in the analysis of heavy-ion fusion reactions. General unitarity defect arguments are used for this purpose. With the aid of an inverse dispersion relation, which gives the imaginary part of the fusion inclusive polarization potential in terms of the principal part integral involving the real part of the inclusive polarization potential, the sub-barrier fusion of heavy ions is discussed. The system /sup 16/O+/sup A/Sm is taken as an example.

  1. Cross sections calculated for cold fusion reactions for producing superheavy nuclei

    SciTech Connect

    Smolanczuk, Robert

    2008-08-15

    We propose a handy formula for calculating the formation cross sections for optimal bombarding energies for transactinides (superheavy elements). By means of the proposed formula the cross sections for asymmetric and symmetric cold fusion reactions (one-neutron-out reactions) are calculated. The fusion barrier and its position are calculated by using the folding heavy-ion potential that for spherical reaction partners has the form of a seventh-order polynomial of the radial coordinate with built-in dependence on the thickness of the nuclear surface, as well as on the separation energy of the least bound nucleon. Possibilities of further experimental exploitation of cold fusion in producing the superheavy nuclei are briefly discussed.

  2. Competition between fusion and quasi-fission in heavy ion induced reactions

    SciTech Connect

    Back, B.B.

    1986-09-01

    Quantitative analyses of angular distributions and angle-mass correlations have been applied to the U + Ca reaction to obtain upper limit estimates for the cross sections for complete fusion near or below the interaction barrier. Extrapolating to the systems Ca + Cm and Ca + Es using the well established scaling properties of the extra push model, an estimate of the cross sections relevant to the efforts of synthesizing super-heavy elements in the region Z = 116 and N = 184 via heavy-ion fusion reactions are obtained. A simple evaporation calculation using properties of the super heavy elements shows that the failure to observe super-heavy elements with the Ca + Cm reaction is consistent with estimates of the complete fusion process. 33 refs., 9 figs., 1 tab.

  3. Equation of state of hot polarized nuclear matter and heavy-ion fusion reactions

    SciTech Connect

    Ghodsi, O. N.; Gharaei, R.

    2011-08-15

    We employ the equation of state of hot polarized nuclear matter to simulate the repulsive force caused by the incompressibility effects of nuclear matter in the fusion reactions of heavy colliding ions. The results of our studies reveal that temperature effects of compound nuclei have significant importance in simulating the repulsive force on the fusion reactions for which the temperature of the compound nucleus increases up to about 2 MeV. Since the equation of state of hot nuclear matter depends upon the density and temperature of the nuclear matter, it has been suggested that, by using this equation of state, one can simulate simultaneously both the effects of the precompound nucleons' emission and the incompressibility of nuclear matter to calculate the nuclear potential in fusion reactions within a static formalism such as the double-folding (DF) model.

  4. Fusion and quasi-fission dynamics in nearly-symmetric reactions

    NASA Astrophysics Data System (ADS)

    Wang, Ning; Zhao, Kai; Li, ZhuXia

    2015-11-01

    Some nearly-symmetric fusion reactions are systematically investigated with the improved quantum molecular dynamics (ImQMD) model. By introducing two-body inelastic scattering in the Fermi constraint procedure, the stability of an individual nucleus and the description of fusion cross sections at energies near the Coulomb barrier can be further improved. Simultaneously, the quasifission process in 154Sm+160Gd is also investigated with the microscopic dynamics model for the first time. We find that at energies above the Bass barrier, the fusion probability is smaller than 10-5 for this reaction, and the nuclear contact time is generally smaller than 1500 fm/ c. From the central collisions of Sm+Gd, the neutron-rich fragments such as 164,165Gd, 192W can be produced in the ImQMD simulations, which implies that the quasi-fission reaction could be an alternative way to synthesize new neutron-rich heavy nuclei.

  5. Probing systematic model dependence of complete fusion for reactions with the weakly bound projectiles Li,76

    NASA Astrophysics Data System (ADS)

    Kundu, A.; Santra, S.; Pal, A.; Chattopadhyay, D.; Nayak, B. K.; Saxena, A.; Kailas, S.

    2016-07-01

    Background: Complete fusion cross section measurements involving weakly bound projectiles show suppression at above-barrier energies compared to coupled-channels (CC) calculations, but no definite conclusion could be drawn for sub-barrier energies. Different CC models often lead to contrasting results. Purpose: We aim to investigate the differences in the fusion cross sections predicted by commonly used CC calculations, using codes such as fresco and ccfull, when compared to experimental data. Methods: The fusion cross sections are normalized to a dimensionless form by isolating the effect of only dynamic channel couplings calculated by both fresco and ccfull, by the method of fusion functions, and compared to a universal fusion function. This acts as a probe for obtaining the model dependence of fusion. Results: A difference is observed between the predictions of fresco and ccfull for all the reactions involving Li,76 as projectiles, and it is noticeably more for systems involving 7Li. Conclusions: With the theoretical foundations of the two CC models being different, their calculation of fusion is different even for the same system. The conclusion about the enhancement or suppression of fusion cross sections is model dependent.

  6. Fusion-product transport in axisymmetric tokamaks: losses and thermalization

    SciTech Connect

    Hively, L.M.

    1980-01-01

    High-energy fusion-product losses from an axisymmetric tokamak plasma are studied. Prompt-escape loss fluxes (i.e. prior to slowing down) are calculated including the non-separable dependence of flux as a function of poloidal angle and local angle-of-incidence at the first wall. Fusion-product (fp) thermalization and heating are calculated assuming classical slowing down. The present analytical model describes fast ion orbits and their distribution function in realistic, high-..beta.., non-circular tokamak equilibria. First-orbit losses, trapping effects, and slowing-down drifts are also treated.

  7. Genotoxicity testing of Maillard reaction products.

    PubMed

    Shibamoto, T

    1989-01-01

    Since the development of short-term genotoxicity tests such as the Ames assay, the mutagenicity of Maillard reaction products has been tested extensively. Some products have exhibited strong activity. For example, one of the earliest studies demonstrated some mutagenic activity in a dichloromethane extract of a D-glucose/ammonia Maillard model system. Many researchers have attempted to pinpoint the principal chemical(s) of mutagenicity of the Maillard products using various sugar-amino acid browning model systems over last two decades. However, no mutagenic individual Maillard product has been isolated and identified. Nitrite has been also used as a reactant in browning reaction model systems, primarily to investigate the formation of potentially mutagenic or carcinogenic N-nitroso compounds. Recently some potent mutagens isolated from pyrolyzed amino acids or proteins have begun to receive attention as Maillard reaction products. PMID:2675034

  8. Analysis of the role of neutron transfer in asymmetric fusion reactions at subbarrier energies

    SciTech Connect

    Ogloblin, A. A.; Zhang, H. Q.; Lin, C. J.; Jia, H. M.; Khlebnikov, S. V.; Kuzmin, E. A.; Danilov, A. N.; Demyanova, A. S.; Trzaska, W. H.; Xu, X. X.; Yang, F.; Sargsyan, V. V. Adamian, G. G.; Antonenko, N. V.; Scheid, W.

    2015-12-15

    The excitation functions were measured for the {sup 28}Si + {sup 208}Pb complete-fusion (capture) reaction at deep subbarrier energies. The results were compared with the cross sections predicted within the quantum diffusion approach. The role of neutron transfer in the case of positive Q values in the {sup 28}Si + {sup 124}Sn, {sup 208}Pb; {sup 30}Si + {sup 124}Sn, {sup 208}Pb; {sup 20}Ne + {sup 208}Pb; {sup 40}Ca + {sup 96}Zr; and {sup 134}Te + {sup 40}Ca complete-fusion (capture) reactions is discussed.

  9. Antibody-independent Targeted Quantification of TMPRSS2-ERG Fusion Protein Products in Prostate Cancer

    SciTech Connect

    He, Jintang; Sun, Xuefei; Shi, Tujin; Schepmoes, Athena A.; Fillmore, Thomas L.; Petyuk, Vladislav A.; Xie, Fang; Zhao, Rui; Gritsenko, Marina A.; Yang, Feng; Kitabayashi, Naoki; Chae, Sung Suk; Rubin, Mark; Siddiqui, Javed; Wei, John; Chinnaiyan, Arul M.; Qian, Weijun; Smith, Richard D.; Kagan, Jacob; Srivastava, Sudhir; Rodland, Karin D.; Liu, Tao; Camp, David G.

    2014-10-01

    Fusions between the transmembrane protease serine 2 (TMPRSS2) and ETS related gene (ERG) represent one of the most specific biomarkers that define a distinct molecular subtype of prostate cancer. The studies on TMPRSS2-ERG gene fusions have seldom been performed at the protein level, primarily due to the lack of high-quality antibodies or an antibody-independent method that is sufficiently sensitive for detecting the truncated ERG protein products resulting from TMPRSS2-ERG gene fusions and alternative splicing. Herein, we applied a recently developed PRISM (high-pressure high-resolution separations with intelligent selection and multiplexing)-SRM (selected reaction monitoring) strategy for quantifying ERG protein in prostate cancer cell lines and tumors. The highly sensitive PRISM-SRM assays led to confident detection of 6 unique ERG peptides in either the TMPRSS2-ERG positive cell lines or tissues but not in the negative controls, indicating that ERG protein expression is highly correlated with TMPRSS2-ERG gene rearrangements. Significantly, our results demonstrated for the first time that at least two groups of ERG protein isoforms were simultaneously expressed at variable levels in TMPRSS2-ERG positive samples as evidenced by concomitant detection of two mutually exclusive peptides. Three peptides shared across almost all fusion protein products were determined to be the most abundant peptides, and hence can be used as “signature” peptides for detecting ERG overexpression resulting from TMPRSS2-ERG gene fusion. These PRISM-SRM assays provide valuable tools for studying TMPRSS2-ERG gene fusion protein products, thus improving our understanding of the role of TMPRSS2-ERG gene fusion in the biology of prostate cancer.

  10. Fusion reactions and experimental approaches to the synthesis of superheavy nuclei

    SciTech Connect

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

    1998-02-15

    The question whether the asymmetric actinide based heavy ion reactions could be used for the synthesis of heavy (Z{>=}106) nuclides is essential from the point of view of the study of limitation on fusion, it is also important in such reactions new nuclides close to the magic number N=162 can be produced. Thus as the problem of a hindrance to fusion still remains unsolved the high excitation energy of the compound nucleus looks to be an obvious obstacle to using these reactions. Using the gas-filled recoil separator and electrostatic recoil separator VAS-SILISSA installed at the beam lines of the U-400 heavy ion cyclotron of the FLNR JINR we investigated the fusion reactions leading to 102, 103, 104, 105 and heaviest isotopes of the 106, 108 and 110 elements. The analysis of the measured cross-sections did not reveal any evidence of a hindrance to fusion at the ion bombarding energy close to the Coulomb barrier. {sup 48}Ca+{sup 232}Th{yields}{sup 280}110*, {sup 48}Ca+{sup 238}U{yields}{sup 286}112*, {sup 48}Ca+{sup 244}Pu{yields}{sup 292}114* appear to be the best reactions from the point of view of their cross-sections.

  11. The fusion-fission process in the reaction {sup 34}S+{sup 186}W near the interaction barrier

    SciTech Connect

    Harca, I. M.; Dmitriev, S.; Itkis, J.; Kozulin, E. M.; Knyazheva, G.; Loktev, T.; Novikov, K.; Azaiez, F.; Gottardo, A.; Matea, I.; Verney, D.; Hanappe, F.; Piot, J.; Schmitt, C.; Vardaci, E.

    2015-02-24

    The reaction {sup 34}S+{sup 186}W at E{sub lab}=160 MeV was investigated with the aim of diving into the features of the fusion-fission process. Gamma rays in coincidence with binary reaction fragments were measured using the high efficiency gamma-ray spectrometer ORGAM at the TANDEM Accelerator facility of I.P.N., Orsay, and the time-of-flight spectrometer for fission fragments (FF) registration CORSET of the Flerov Laboratory of Nuclear Reactions (FLNR), Dubna. The coupling of the ORGAM and CORSET setups offers the unique opportunity of extracting details for characterizing the fusion-fission process and gives information regarding production of neutron-rich heavy nuclei. The FF–γ coincidence method is of better use then the γ – γ coincidence method when dealing with low statistic measurements and also offers the opportunity to precisely correct the Dopler shift for in-flight emitted gamma rays. Evidence of symmetric and asymmetric fission modes were observed in the mass and TKE distributions, occurring due to shell effects in the fragments. Coincident measurements allow for discrimination between the gamma rays by accepting a specific range within the mass distribution of the reaction products. Details regarding the experimental setup, methods of processing the acquisitioned data and preliminary results are presented.

  12. An evolved Mxe GyrA intein for enhanced production of fusion proteins.

    PubMed

    Marshall, Carrie J; Grosskopf, Vanessa A; Moehling, Taylor J; Tillotson, Benjamin J; Wiepz, Gregory J; Abbott, Nicholas L; Raines, Ronald T; Shusta, Eric V

    2015-02-20

    Expressing antibodies as fusions to the non-self-cleaving Mxe GyrA intein enables site-specific, carboxy-terminal chemical modification of the antibodies by expressed protein ligation (EPL). Bacterial antibody-intein fusion protein expression platforms typically yield insoluble inclusion bodies that require refolding to obtain active antibody-intein fusion proteins. Previously, we demonstrated that it was possible to employ yeast surface display to express properly folded single-chain antibody (scFv)-intein fusions, therefore permitting the direct small-scale chemical functionalization of scFvs. Here, directed evolution of the Mxe GyrA intein was performed to improve both the display and secretion levels of scFv-intein fusion proteins from yeast. The engineered intein was shown to increase the yeast display levels of eight different scFvs by up to 3-fold. Additionally, scFv- and green fluorescent protein (GFP)-intein fusion proteins can be secreted from yeast, and while fusion of the scFvs to the wild-type intein resulted in low expression levels, the engineered intein increased scFv-intein production levels by up to 30-fold. The secreted scFv- and GFP-intein fusion proteins retained their respective binding and fluorescent activities, and upon intein release, EPL resulted in carboxy-terminal azide functionalization of the target proteins. The azide-functionalized scFvs and GFP were subsequently employed in a copper-free, strain-promoted click reaction to site-specifically immobilize the proteins on surfaces, and it was demonstrated that the functionalized, immobilized scFvs retained their antigen binding specificity. Taken together, the evolved yeast intein platform provides a robust alternative to bacterial intein expression systems. PMID:25384269

  13. Low Energy Nuclear Reaction Products at Surfaces

    NASA Astrophysics Data System (ADS)

    Nagel, David J.

    2008-03-01

    This paper examines the evidence for LENR occurring on or very near to the surface of materials. Several types of experimental indications for LENR surface reactions have been reported and will be reviewed. LENR result in two types of products, energy and the appearance of new elements. The level of instantaneous power production can be written as the product of four factors: (1) the total area of the surface on which the reactions can occur, (2) the fraction of the area that is active at any time, (3) the reaction rate, that is, the number of reactions per unit active area per second, and (4) the energy produced per reaction. Each of these factors, and their limits, are reviewed. A graphical means of relating these four factors over their wide variations has been devised. The instantaneous generation of atoms of new elements can also be written as the product of the first three factors and the new elemental mass produced per reaction. Again, a graphical means of presenting the factors and their results over many orders of magnitude has been developed.

  14. Inertial confinement fusion reaction chamber and power conversion system study

    SciTech Connect

    Maya, I.; Schultz, K.R.; Battaglia, J.M.; Buksa, J.J.; Creedson, R.L.; Erlandson, O.D.; Levine, H.E.; Roelant, D.F.; Sanchez, H.W.; Schrader, S.A.

    1984-09-01

    GA Technologies has developed a conceptual ICF reactor system based on the Cascade rotating-bed reaction chamber concept. Unique features of the system design include the use of low activation SiC in a reaction chamber constructed of box-shaped tiles held together in compression by prestressing tendons to the vacuum chamber. Circulating Li/sub 2/O granules serve as the tritium breeding and energy transport material, cascading down the sides of the reaction chamber to the power conversion system. The total tritium inventory of the system is 6 kg; tritium recovery is accomplished directly from the granules via the vacuum system. A system for centrifugal throw transport of the hot Li/sub 2/O granules from the reaction chamber to the power conversion system has been developed. A number of issues were evaluated during the course of this study. These include the response of first-layer granules to the intense microexplosion surface heat flux, cost effective fabrication of Li/sub 2/O granules, tritium inventory and recovery issues, the thermodynamics of solids-flow options, vacuum versus helium-medium heat transfer, and the tradeoffs of capital cost versus efficiency for alternate heat exchange and power conversion system option. The resultant design options appear to be economically competitive, safe, and environmentally attractive.

  15. Concept of a charged fusion product diagnostic for NSTX.

    PubMed

    Boeglin, W U; Valenzuela Perez, R; Darrow, D S

    2010-10-01

    The concept of a new diagnostic for NSTX to determine the time dependent charged fusion product emission profile using an array of semiconductor detectors is presented. The expected time resolution of 1-2 ms should make it possible to study the effect of magnetohydrodynamics and other plasma activities (toroidal Alfvén eigenmodes (TAE), neoclassical tearing modes (NTM), edge localized modes (ELM), etc.) on the radial transport of neutral beam ions. First simulation results of deuterium-deuterium (DD) fusion proton yields for different detector arrangements and methods for inverting the simulated data to obtain the emission profile are discussed. PMID:21033827

  16. Concept of a charged fusion product diagnostic for NSTX

    SciTech Connect

    Boeglin, W. U.; Valenzuela Perez, R.; Darrow, D. S.

    2010-10-15

    The concept of a new diagnostic for NSTX to determine the time dependent charged fusion product emission profile using an array of semiconductor detectors is presented. The expected time resolution of 1-2 ms should make it possible to study the effect of magnetohydrodynamics and other plasma activities (toroidal Alfven eigenmodes (TAE), neoclassical tearing modes (NTM), edge localized modes (ELM), etc.) on the radial transport of neutral beam ions. First simulation results of deuterium-deuterium (DD) fusion proton yields for different detector arrangements and methods for inverting the simulated data to obtain the emission profile are discussed.

  17. Controlled shock shells and intracluster fusion reactions in the explosion of large clusters

    SciTech Connect

    Peano, F.

    2006-05-15

    The ion phase-space dynamics in the Coulomb explosion of very large ({approx}10{sup 6}-10{sup 7} atoms) deuterium clusters can be tailored using two consecutive laser pulses with different intensities and an appropriate time delay. For suitable sets of laser parameters (intensities and delay), large-scale shock shells form during the explosion, thus highly increasing the probability of fusion reactions within the single exploding clusters. In order to analyze the ion dynamics and evaluate the intracluster reaction rate, a one-dimensional theory is used, which approximately accounts for the electron expulsion from the clusters. It is found that, for very large clusters (initial radius {approx}100 nm), and optimal laser parameters, the intracluster fusion yield becomes comparable to the intercluster fusion yield. The validity of the results is confirmed with three-dimensional particle-in-cell simulations.

  18. Microscopic study of 40Ca+58,64Ni fusion reactions

    NASA Astrophysics Data System (ADS)

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

    2016-03-01

    Background: Heavy-ion fusion reactions at energies near the Coulomb barrier are influenced by couplings between the relative motion and nuclear intrinsic degrees of freedom of the colliding nuclei. The time-dependent Hartree-Fock (TDHF) theory, incorporating the couplings at the mean-field level, as well as the coupled-channels (CC) method are standard approaches to describe low energy nuclear reactions. Purpose: To investigate the effect of couplings to inelastic and transfer channels on the fusion cross sections for the reactions 40Ca+58Ni and 40Ca+64Ni . Methods: Fusion cross sections around and below the Coulomb barrier have been obtained from CC calculations, using the bare nucleus-nucleus potential calculated with the frozen Hartree-Fock method and coupling parameters taken from known nuclear structure data. The fusion thresholds and neutron transfer probabilities have been calculated with the TDHF method. Results: For 40Ca+58Ni , the TDHF fusion threshold is in agreement with the most probable barrier obtained in the CC calculations including the couplings to the low-lying octupole 31- state for 40Ca and to the low-lying quadrupole 21+ state for 58Ni. This indicates that the octupole and quadrupole states are the dominant excitations while neutron transfer is shown to be weak. For 40Ca+64Ni , the TDHF barrier is lower than predicted by the CC calculations including the same inelastic couplings as those for 40Ca+58Ni . TDHF calculations show large neutron transfer probabilities in 40Ca+64Ni which could result in a lowering of the fusion threshold. Conclusions: Inelastic channels play an important role in 40Ca+58Ni and 40Ca+64Ni reactions. The role of neutron transfer channels has been highlighted in 40Ca+64Ni .

  19. 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

  20. On the fusion triple product and fusion power gain of tokamak pilot plants and reactors

    NASA Astrophysics Data System (ADS)

    Costley, A. E.

    2016-06-01

    The energy confinement time of tokamak plasmas scales positively with plasma size and so it is generally expected that the fusion triple product, nTτ E, will also increase with size, and this has been part of the motivation for building devices of increasing size including ITER. Here n, T, and τ E are the ion density, ion temperature and energy confinement time respectively. However, tokamak plasmas are subject to operational limits and two important limits are a density limit and a beta limit. We show that when these limits are taken into account, nTτ E becomes almost independent of size; rather it depends mainly on the fusion power, P fus. In consequence, the fusion power gain, Q fus, a parameter closely linked to nTτ E is also independent of size. Hence, P fus and Q fus, two parameters of critical importance in reactor design, are actually tightly coupled. Further, we find that nTτ E is inversely dependent on the normalised beta, β N; an unexpected result that tends to favour lower power reactors. Our findings imply that the minimum power to achieve fusion reactor conditions is driven mainly by physics considerations, especially energy confinement, while the minimum device size is driven by technology and engineering considerations. Through dedicated R&D and parallel developments in other fields, the technology and engineering aspects are evolving in a direction to make smaller devices feasible.

  1. Charged particle decay of hot and rotating 88Mo nuclei in fusion-evaporation reactions

    NASA Astrophysics Data System (ADS)

    Valdré, S.; Piantelli, S.; Casini, G.; Barlini, S.; Carboni, S.; Ciemała, M.; Kmiecik, M.; Maj, A.; Mazurek, K.; Cinausero, M.; Gramegna, F.; Kravchuk, V. L.; Morelli, L.; Marchi, T.; Baiocco, G.; Bardelli, L.; Bednarczyk, P.; Benzoni, G.; Bini, M.; Blasi, N.; Bracco, A.; Brambilla, S.; Bruno, M.; Camera, F.; Chbihi, A.; Corsi, A.; Crespi, F. C. L.; D'Agostino, M.; Degerlier, M.; Fabris, D.; Fornal, B.; Giaz, A.; Krzysiek, M.; Leoni, S.; Matejska-Minda, M.; Mazumdar, I.; MÈ©czyński, W.; Million, B.; Montanari, D.; Myalski, S.; Nicolini, R.; Olmi, A.; Pasquali, G.; Prete, G.; Roberts, O. J.; Styczeń, J.; Szpak, B.; Wasilewska, B.; Wieland, O.; Wieleczko, J. P.; ZiÈ©bliński, M.

    2016-03-01

    A study of fusion-evaporation and (partly) fusion-fission channels for the 88Mo compound nucleus, produced at different excitation energies in the reaction 48Ti+40Ca at 300, 450, and 600 MeV beam energies, is presented. Fusion-evaporation and fusion-fission cross sections have been extracted and compared with the existing systematics. Experimental data concerning light charged particles have been compared with the prediction of the statistical model in its implementation in the gemini++ code, well suited even for high spin systems, in order to tune the main model parameters in a mass region not abundantly covered by exclusive experimental data. Multiplicities for light charged particles emitted in fusion evaporation events are also presented. Some discrepancies with respect to the prediction of the statistical model have been found for forward emitted α particles; they may be due both to pre-equilibrium emission and to reaction channels (such as deep inelastic collisions or quasifission/quasifusion) different from the compound nucleus formation.

  2. Production Cross Sections for Synthesis of Nuclides with Z = 118 IN Large Mass Transfer Reactions

    NASA Astrophysics Data System (ADS)

    Wang, Nan; Jin, Xin; Yang, Shuang; Zhao, En-Guang

    The production cross sections for the synthesis of superheavy nuclei with charge number 118 are studied with the di-nuclear system model with dynamical potential surface (DNS-DyPES model). The dynamical potential energy surface (PES) and the fusion probabilities for 48Ca bombarding Cf nuclei reactions are studied. By multiplying the capture cross section, fusion probability and survival probability, the evaporation residue(ER) cross sections for superheavy nuclei with Z = 118 are obtained. And the excitation functions for the reactions with a mixture target of Cf isotopes are also shown.

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

    SciTech Connect

    Jung, J; Yoon, D; Shin, H; Kim, M; Suh, T

    2015-06-15

    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 that 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.

  4. Study of the mechanism of muon-catalyzed t + t fusion reaction

    SciTech Connect

    Bogdanova, L. N.; Demin, D. L.; Filchenkov, V. V.

    2015-01-15

    The mechanism for the muon catalyzed fusion reaction t + t → {sup 4}He + 2n + 11.33 MeV is investigated. The model of the cascade reaction with {sup 5}He as an intermediate state is considered, both the ground and the first exited states being taken into account. The neutron energy spectrum measured in the recent experiment is compared with the Monte-Carlo-simulated one. Varying reaction parameters, we obtain optimum values for the relative weights of the {sup 5}He ground and excited states and for the excitation energy and width of the excited state.

  5. REACTION PRODUCTS FROM THE CHLORINATION OF SEAWATER

    EPA Science Inventory

    Chemical treatment of natural waters, in particular the use of chlorine as a biocide, modifies the chemistry of these waters in ways that are not fully understood. The research described in this report examined both inorganic and organic reaction products from the chlorination of...

  6. Fission-Fusion: A new reaction mechanism for nuclear astrophysics based on laser-ion acceleration

    NASA Astrophysics Data System (ADS)

    Thirolf, P. G.; Habs, D.; Gross, M.; Allinger, K.; Bin, J.; Henig, A.; Kiefer, D.; Ma, W.; Schreiber, J.

    2011-10-01

    We propose to produce neutron-rich nuclei in the range of the astrophysical r-process around the waiting point N = 126 by fissioning a dense laser-accelerated thorium ion bunch in a thorium target (covered by a CH2 layer), where the light fission fragments of the beam fuse with the light fission fragments of the target. Via the `hole-boring' mode of laser Radiation Pressure Acceleration using a high-intensity, short pulse laser, very efficiently bunches of 232Th with solid-state density can be generated from a Th target and a deuterated CD2 foil, both forming the production target assembly. Laser-accelerated Th ions with about 7 MeV/u will pass through a thin CH2 layer placed in front of a thicker second Th foil (both forming the reaction target) closely behind the production target and disintegrate into light and heavy fission fragments. In addition, light ions (d,C) from the CD2 layer of the production target will be accelerated as well, inducing the fission process of 232Th also in the second Th layer. The laser-accelerated ion bunches with solid-state density, which are about 1014 times more dense than classically accelerated ion bunches, allow for a high probability that generated fission products can fuse again. The high ion beam density may lead to a strong collective modification of the stopping power, leading to significant range and thus yield enhancement. Using a high-intensity laser as envisaged for the ELI-Nuclear Physics project in Bucharest (ELI-NP), order-of-magnitude estimates promise a fusion yield of about 103 ions per laser pulse in the mass range of A = 180-190, thus enabling to approach the r-process waiting point at N = 126.

  7. Charged fusion product loss measurements using nuclear activation.

    PubMed

    Bonheure, G; Hult, M; González de Orduña, R; Arnold, D; Dombrowski, H; Laubenstein, M; Wieslander, E; Vermaercke, P; Murari, A; Popovichev, S; Mlynar, J

    2010-10-01

    In ITER, α particle loss measurements will be required in order to understand the alpha particle physics. Techniques capable of operating in a fusion reactor environment need further development. Recent experimental studies on JET demonstrated the potential of nuclear activation to measure the flux of escaping MeV ions. New results from MeV ion induced activation of metallic, ceramic, and crystal samples placed near the plasma edge are reported. Activation products were measured as function of orientation with respect to the magnetic field as well as function of the distance to the plasma. Sample activity was measured using ultralow-level gamma-ray spectrometry. Distribution of 14.68 MeV fusion proton induced activation products is strongly anisotropic in agreement with simulations and falls off sharply with increasing distance to the plasma. Prospects for using the technique in ITER are discussed. PMID:21058458

  8. Systematic study of suppression of complete fusion in reactions involving weakly bound nuclei at energies above the Coulomb barrier

    NASA Astrophysics Data System (ADS)

    Wang, Bing; Zhao, Wei-Juan; Diaz-Torres, Alexis; Zhao, En-Guang; Zhou, Shan-Gui

    2016-01-01

    Complete fusion excitation functions of reactions involving breakup are studied by using the empirical coupled-channel (ECC) model with breakup effects considered. An exponential function with two parameters is adopted to describe the prompt-breakup probability in the ECC model. These two parameters are fixed by fitting the measured prompt-breakup probability or the complete fusion cross sections. The suppression of complete fusion at energies above the Coulomb barrier is studied by comparing the data with the predictions from the ECC model without the breakup channel considered. The results show that the suppression of complete fusion is roughly independent of the target for the reactions involving the same projectile.

  9. Lattice fusion rules and logarithmic operator product expansions

    NASA Astrophysics Data System (ADS)

    Gainutdinov, A. M.; Vasseur, R.

    2013-03-01

    The interest in Logarithmic Conformal Field Theories (LCFTs) has been growing over the last few years thanks to recent developments coming from various approaches. A particularly fruitful point of view consists in considering lattice models as regularizations for such quantum field theories. The indecomposability then encountered in the representation theory of the corresponding finite-dimensional associative algebras exactly mimics the Virasoro indecomposable modules expected to arise in the continuum limit. In this paper, we study in detail the so-called Temperley-Lieb (TL) fusion functor introduced in physics by Read and Saleur [N. Read and H. Saleur, Associative-algebraic approach to logarithmic conformal field theories, Nucl. Phys. B 777 (2007) 316]. Using quantum group results, we provide rigorous calculations of the fusion of various TL modules at roots of unity cases. Our results are illustrated by many explicit examples relevant for physics. We discuss how indecomposability arises in the "lattice" fusion and compare the mechanisms involved with similar observations in the corresponding field theory. We also discuss the physical meaning of our lattice fusion rules in terms of indecomposable operator product expansions of quantum fields.

  10. Deep Sub-Barrier Fusion Enhancement in the {sup 6}He+{sup 206}Pb Reaction

    SciTech Connect

    Penionzhkevich, Yu.E.; Zagrebaev, V.I.; Lukyanov, S.M.; Kalpakchieva, R.

    2006-04-28

    The fusion of {sup 6}He with {sup 206}Pb has been studied at energies close to and below the Coulomb barrier. The experiment was carried out at the Dubna Radioactive Ion Beams complex of FLNR, JINR. The {sup 6}He beam intensity was about 5x10{sup 6} pps, the maximum energy being 60.3{+-}0.4 MeV. The yield of the {sup 210}Po isotope, produced in the 2n-evaporation channel, demonstrates an extremely large enhancement of the sub-barrier fusion cross section as compared with the {sup 4}He+{sup 208}Pb reaction. This enhancement is most likely due to the mechanism of 'sequential fusion' with an intermediate neutron transfer from {sup 6}He to the Pb nucleus with positive Q values.

  11. Intimations of neck formation in heavy-ion subbarrier fusion reactions

    SciTech Connect

    Stelson, P.H.

    1990-07-01

    Since the observed fusion cross sections for collisions between heavy ions at subbarrier energies are orders of magnitude larger than would be expected for barrier tunnelling, one is faced with the task of identifying the basic force which is strong enough to overcome the strong Coulomb force and bring about fusion. The two possibilities seem to be excursions of the nuclear surface (and strong nuclear force) due to collective motions of the colliding nuclei and formation of a neck of nuclear matter. The first possibility has received the most attention. However, the systematics of fusion cross sections suggest neck formation is playing an important role. Neck formation can also result in a reseparation of the composite system and we review the experimental information on these reactions at barrier and subbarrier energies. 15 refs., 18 figs.

  12. Spin polarization effects in the /sup 3/H(d,n)/sup 4/He fusion reaction

    SciTech Connect

    Conzett, H.E.; Rioux, C.

    1985-06-01

    A recent investigation has shown that the /sup 3/H(d,n)/sup 4/He fusion reaction rate could be enhanced by a factor of 3/2 if the fusion plasma consisted of both polarized deuterons and tritons, forming exclusively the channel-spin S = 3/2, J = 3/2/sup +/ state. This result follows simply from the statistical weights of the quartet S = 3/2 and doublet S = 1/2 initial states, with the assumption of the single J = 3/2/sup +/ reaction amplitude. Since, with a small but nonzero J = 1/2/sup +/ amplitude, the maximum enhancement of the reaction occurs at the peak of the J = 3/2/sup +/ resonance, corresponding to a deuteron lab energy of 107 keV, it is of obvious interest to know what the enhancement would be at the lower energies that are typical of fusion plasmas. We are able to address this question by extending earlier calculations which gave the values of all of the spin-polarization observables at this J = 3/2/sup +/ resonance in both the /sup 3/H(d,n)/sup 4/He and the /sup 3/He(d,p)/sup 4/He reactions.

  13. Charged fusion product and fast ion loss in TFTR

    SciTech Connect

    Zweben, S.J.; Darrow, D.S.; Fredrickson, E.D.; Mynick, H.E.; White, R.B.; Biglari, H.; Bretz, N.; Budny, R.; Bush, C.E.; Chang, C.S.; Chen, L.; Cheng, C.Z.; Fu, G.Y.; Hammett, G.W.; Hawryluk, R.J.; Hosea, J.; Johnson, L.; Mansfield, D.; McGuire, K.; Medley, S.S.; Nazikian, R.; Owens, D.K.; Park, H.; Park, J.; Phillips, C.K.; Schivell, J.; Stratton, B.C.; Ulrickson, M.; Wilson, R.; Young, K.M.; Boivin, R.; Machuzak, J.S.; Woskov, P.; Fisher, R.; McChesney, J.; Fonck, R.; McKee, G.; Tuszewski, M.

    1993-03-01

    Several different fusion product and fast ion loss processes have been observed in TFTR using an array of pitch angle, energy and time resolved scintillator detectors located near the vessel wall. For D-D fusion products (3 MeV protons and 1 MeV tritons) the observed loss is generally consistent with expected first-orbit loss for Ip < 1.4 MA, except near the outer midplane where stochastic TF ripple loss dominates when Ip > I MA. However, at higher currents, Ip = 1.4--2.5 MA, an NM induced D-D fusion product loss can be up to 3-4 times larger than the first-orbit loss, particularly at high beam powers, P {ge} 25 MW. The MHD induced loss of 100 KeV neutron beam ions and {approximately}0.5 MeV ICRF minority tail tons has also been measured {le} 459 below the outer midplane. be potential implications of these results for D-T alpha particle experiments in TFTR and ITER are described.

  14. Charged fusion product and fast ion loss in TFTR

    SciTech Connect

    Zweben, S.J.; Darrow, D.S.; Fredrickson, E.D.; Mynick, H.E.; White, R.B.; Biglari, H.; Bretz, N.; Budny, R.; Bush, C.E.; Chang, C.S.; Chen, L.; Cheng, C.Z.; Fu, G.Y.; Hammett, G.W.; Hawryluk, R.J.; Hosea, J.; Johnson, L.; Mansfield, D.; McGuire, K.; Medley, S.S.; Nazikian, R.; Owens, D.K.; Park, H.; Park, J.; Phillips, C.K.; Schivell, J.; Stratton, B.C.; Ulrickson, M.; Wilson, R.; Young, K.M. (Princeton Univ., NJ (United Sta

    1993-03-01

    Several different fusion product and fast ion loss processes have been observed in TFTR using an array of pitch angle, energy and time resolved scintillator detectors located near the vessel wall. For D-D fusion products (3 MeV protons and 1 MeV tritons) the observed loss is generally consistent with expected first-orbit loss for Ip < 1.4 MA, except near the outer midplane where stochastic TF ripple loss dominates when Ip > I MA. However, at higher currents, Ip = 1.4--2.5 MA, an NM induced D-D fusion product loss can be up to 3-4 times larger than the first-orbit loss, particularly at high beam powers, P [ge] 25 MW. The MHD induced loss of 100 KeV neutron beam ions and [approximately]0.5 MeV ICRF minority tail tons has also been measured [le] 459 below the outer midplane. be potential implications of these results for D-T alpha particle experiments in TFTR and ITER are described.

  15. Hot fusion-evaporation cross sections of 44Ca-induced reactions with lanthanide targets

    NASA Astrophysics Data System (ADS)

    Werke, T. A.; Mayorov, D. A.; Alfonso, M. C.; Tereshatov, E. E.; Folden, C. M.

    2015-11-01

    Background: Previously reported cross sections of 45Sc-induced reactions with lanthanide targets are much smaller than 48Ca-induced reactions on the same targets. 44Ca is one proton removed from 45Sc and could be used to produce nuclei with a relative neutron content between those produced in the 45Sc- and 48Ca-induced reactions. Purpose: As part of a systematic investigation of fusion-evaporation reactions, cross sections of 44Ca-induced reactions on lanthanide targets were measured. These results are compared to available data for 48Ca- and 45Sc-induced fusion-evaporation cross sections on the same lanthanide targets. Collectively, these data provide insight into the importance of the survival against fission of excited compound nuclei produced near spherical shell closures. Methods: A beam of 6+Ca at an energy of ≈5 MeV /u was delivered by the K500 superconducting cyclotron at the Cyclotron Institute at Texas A&M University. The desired evaporation residues were selected by the Momentum Achromat Recoil Spectrometer and identified via their characteristic α -decay energies. Excitation functions for the 44Ca+158Gd ,159Tb, and 162Dy reactions were measured at five or more energies each. A theoretical model was employed to study the fusion-evaporation process. Results: The 44Ca-induced reactions have x n cross sections that are two orders of magnitude larger than 45Sc-induced reactions but two orders of magnitude smaller than 48Ca-induced reactions on the same targets. Proton emission competes effectively with neutron emission for the 44Ca+159Tb and 162Dy reactions. The maximum 4 n cross sections in the 44Ca+158Gd ,159Tb, and 162Dy reactions were 2100 ± 230 ,230 ± 20 , and 130 ±20 μ b , respectively. The 44Ca+158Gd and 159Tb cross sections are in good agreement with the respective cross bombardments of 48Ca+154Gd and 45Sc+158Gd once differences in capture cross sections and compound nucleus formation probabilities are corrected for. Conclusions: Excitation

  16. Proliferation Risks of Magneetic Fusion Energy: Clandestine Production, Covert Production and Breakout

    SciTech Connect

    A. Glaser and R.J. Goldston

    2012-03-13

    Nuclear proliferation risks from magnetic fusion energy associated with access to weapon-usable materials can be divided into three main categories: (1) clandestine production of weapon-usable material in an undeclared facility, (2) covert production of such material inn a declared facility, and (3) use of a declared facility in a breakout scenario, in which a state begins production of fissile material without concealing the effort. In this paper we address each of these categories of risks from fusion. For each case, we find that the proliferation risk from fusion systems can be much lower than the equivalent risk from fission systems, if the fusion system is designed to accommodate appropriate safeguards.

  17. Proliferation risks of magnetic fusion energy: clandestine production, covert production and breakout

    NASA Astrophysics Data System (ADS)

    Glaser, A.; Goldston, R. J.

    2012-04-01

    Nuclear proliferation risks from magnetic fusion energy associated with access to weapon-usable materials can be divided into three main categories: (1) clandestine production of weapon-usable material in an undeclared facility, (2) covert production of such material in a declared facility and (3) use of a declared facility in a breakout scenario, in which a state begins production of fissile material without concealing the effort. In this paper, we address each of these categories of risks from fusion. For each case, we find that the proliferation risk from fusion systems can be much lower than the equivalent risk from fission systems, if the fusion system is designed to accommodate appropriate safeguards.

  18. Imaging of fusion reaction zone in plasma focus

    NASA Astrophysics Data System (ADS)

    Zakaullah, M.; Akhtar, Ijaz; Murtaza, G.; Waheed, A.

    1999-08-01

    In a low energy (2.3 kJ) Mather-type deuterium plasma focus, neutron and charged particle emission is investigated by using time-resolved neutron detectors and time-integrated charged particle pinhole imaging camera. The time-integrated charged particle pinhole images demonstrate the varying influence of magnetohydrodynamic (MHD) instabilities vis-a-vis filling pressure. The neutron production mechanism at play strongly depends upon the pressure. At lower pressure, the plasma column is highly unstable due to MHD instabilities and the neutron emission is found to be low with fluence anisotropy exceeding 3.5. At optimum pressure (2.5 mbar for this system), an almost stable dense plasma of about 17 mm3 volume is formed about 5 mm away from the anode, with neutron emission at its highest and the fluence anisotropy lowest. At higher pressure, the plasma column is stable, although it moves away from the anode like a jet and may then be called a moving boiler. In this case, the neutron emission is lowered compared to its optimum value and fluence anisotropy is increased. The data suggest beam-target mechanism at low pressure, trapped gyrating particles at optimum pressure and a jetlike moving boiler at higher pressure.

  19. Production of recombinant oxytocin through sulfitolysis of inteincontaining fusion protein.

    PubMed

    Esipov, Roman S; Stepanenko, Vasily N; Chupova, Larisa A; Miroshnikov, Anatoly I

    2012-05-01

    An artificial gene consisting of seven copies of an oxytocinoyl-lysine encoding sequence arranged in a tandem was synthesized and inserted downstream of the SspDnaB intein gene in a pTWIN1 plasmid. The corresponding fusion protein Dnab-7oxy contained 16 cysteine residues and formed inclusion bodies when expressed in E. coli. The standard protocol involving solubilization of the fusion protein and its autocatalytic cleavage on a chitin resin was not effective because of a very low yield of the cleavage reaction. Attempts to perform a refolding of the intein part of the fusion protein in solution were also unsuccessful because of a high level of protein aggregation. Sulfitolysis of cysteine residues is known to increase a solubility of proteins and peptides. Therefore we suggested a one-step approach that combines solubilization of inclusion bodies and sulfitolysis of a hybrid protein. The fusion protein was completely reduced and solubilized in 8M urea at pH 9.0 in the presence of sodium sulfite and sodium tetrathionate. The sulfitized protein was loaded onto a chitin column, an efficient cleavage was induced by a pH shift from 9.0 to 6.5, and seven successively connected oxytocinoyl- lysine units were released. The heptamer was subjected to trypsinolysis yielding sulfitized monomers of oxytocinoyllysine. Oxytocinoyl-lysine was refolded as described previously and treated by carboxypeptidase B to form the oxytocinic acid. The target oxytocin amide was then synthesized via methyl ester intermediate. Using this approach 6 mg of recombinant oxytocin can be obtained from 1 g of biomass. PMID:22316308

  20. Effects of sawtooth crashes on beam ions and fusion product tritons in JET

    NASA Astrophysics Data System (ADS)

    Marcus, F. B.; Adams, J. M.; Bond, D. S.; Hone, M. A.; Howarth, P. J. A.; Jarvis, O. N.; Loughlin, M. J.; Sadler, G. J.; Van Belle, P.; Watkins, N.

    1994-05-01

    The JET neutron emission profile monitor is used to measure the 2.5 MeV and 14 MeV neutron emission line integrals before and after sawtooth crashes in high d-d neutron yield, hot ion H mode plasmas in the Joint European Torus (JET). Deuterium-deuterium (d-d) fusion produces 2.5 MeV neutrons and 1 MeV tritons (t) at nearly equal rates from its two reaction channels. A plasma current of 3 MA is sufficiently high to contain most of the fusion product tritons, which have birth orbit gyroradii and velocity space distributions similar to those of the 3.5 MeV or particles from d-t fusion. By examining neutron emission line integrals and tomographically deduced local emissivity profiles, an upper limit of 10% can be placed on the net fraction of fusion product tritons which are displaced from the plasma axis by those sawtooth crashes studied. This is a much smaller net fraction than that typically observed, 35-55%, for displaced injected neutral beam deuterium ions. A study of the response of beam injected deuterium ions to a sawtooth crash shows that the change in their axial density depends on the precrash spatial width of the neutron emissivity profile. The fusion product tritons, which have a large precrash spatial width, respond weakly to a crash. This weak response is consistent with the behaviour of the analogous d-d beam thermal neutrons when extrapolated to the corresponding emissivity spatial width. The implication of these observations is that beam ions and 3.5 MeV alpha particles in JET may be relatively resilient to sawtooth clashes, when the spatial width of their density is sufficiently large

  1. Multi-Sampling Ionization Chamber (MUSIC) for measurements of fusion reactions with radioactive beams

    NASA Astrophysics Data System (ADS)

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

    2015-11-01

    A detection technique for high-efficiency measurements of fusion reactions with low-intensity radioactive beams was developed. The technique is based on a Multi-Sampling Ionization Chamber (MUSIC) operating as an active target and detection system, where the ionization gas acts as both target and counting gas. In this way, we can sample an excitation function in an energy range determined by the gas pressure, without changing the beam energy. The detector provides internal normalization to the incident beam and drastically reduces the measuring time. In a first experiment we tested the performance of the technique by measuring the 10,13,15C+12C fusion reactions at energies around the Coulomb barrier.

  2. 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.

  3. Quantum-mechanical description of the initial stage of fusion reaction

    SciTech Connect

    Sargsyan, V. V. Zubov, A.S.; Kanokov, Z.; Adamian, G. G. Antonenko, N. V.

    2009-03-15

    Projectile-nucleus capture by a target nucleus at bombarding energies in the vicinity of the Coulomb barrier is treated on the basis of the reduced-density-matrix formalism. The effect of dissipation and fluctuations on the capture process is taken into account self-consistently within this model. Cross sections for evaporation-residue formation in asymmetric-fusion reactions are found by using the calculated capture probabilities averaged over all orientations of the deformed projectile or target nucleus.

  4. Parameterization of fusion barriers for light-projectiles-induced reactions using the proximity approach

    NASA Astrophysics Data System (ADS)

    Gharaei, R.; Sheibani, J.

    2016-05-01

    In this article we propose a pocket formula for fusion barriers calculated by three versions of the proximity formalism, namely AW 95, Bass 80 and Prox. 2010 potentials, for fusion reactions involving the collisions of the proton and helium projectiles with different targets in mass ranges 51≤ AT ≤ 130 and 40≤ AT ≤ 233 , respectively. For the first type of the colliding systems, it is shown that the proposed pocket formulas are able to predict the actual values of RB and VB within accuracies of ±0.4% and ±0.45% , respectively. Moreover, for the second type of the selected reactions, these accuracies are obtained ±0.24% and ±0.36% , respectively. In this study, the ability of the present pocket formulas is also demonstrated to predict the exact values of the fusion cross sections for our selected mass ranges. A comparison with the results of the previous pocket formulas reveals that our parameterized forms are more successful to reproduce the empirical data of the barrier height and position in the proton- and helium-induced reactions.

  5. Population of ground-state rotational bands of superheavy nuclei produced in complete fusion reactions

    NASA Astrophysics Data System (ADS)

    Zubov, A. S.; Sargsyan, V. V.; Adamian, G. G.; Antonenko, N. V.

    2011-10-01

    Using the statistical and quantum diffusion approaches, we study the population of ground-state rotational bands of superheavy nuclei produced in the fusion-evaporation reactions 208Pb(48Ca,2n)254No, 206Pb(48Ca,2n)252No, and 204Hg(48Ca,2n)250Fm. By describing the relative intensities of E2 transitions between the rotational states, the entry spin distributions of residual nuclei, and the excitation functions for these reactions, the dependence of fission barriers of shell-stabilized nuclei on angular momentum is investigated.

  6. Heavy-ion inertial fusion: influence of target gain on accelerator parameters for vacuum-propagation regimes in reaction chambers

    SciTech Connect

    Mark, J.W.K.; Bangerter, R.O.; Barletta, W.A.; Fawley, W.M.; Judd, D.L.

    1982-03-04

    Target physics imposes requirements on the design of inertial fusion drivers. The influence of beam propagation in near vacuum fusion reaction chambers is evaluated for the relation between target gain and the phase-space requirements of heavy-ion accelerators. Initial results suggest that neutralization of the ion beam has a much greater positive effect than the deleterious one of beam stripping provided that the fusion chamber pressure is < 10/sup -3/ torr (of Li vapor or equivalent).

  7. Absorption-Fluctuation Theorem for Nuclear Reactions: Brink-Axel, Incomplete Fusion and All That

    SciTech Connect

    Hussein, M. S.

    2008-04-17

    We discuss the connection between absorption, averages and fluctuations in nuclear reactions. The fluctuations in the entrance channel result in the compound-nucleus Hauser-Feshbach cross section, and the fluctuations in the intermediate channels result in modifications of multistep reaction cross sections, while the fluctuations in the final channel result in hybrid cross sections that can be used to describe incomplete fusion reactions. We discuss the latter in detail and comment on the validity of the assumptions used in the development of the Surrogate method. We also discuss the theory of multistep reactions with regards to intermediate state fluctuations and the energy dependence and non-locality of the intermediate-channel optical potentials.

  8. Experimental study of the 13C+12C fusion reaction at deep sub-barrier energies

    NASA Astrophysics Data System (ADS)

    Tudor, D.; Chilug, A. I.; Straticiuc, M.; Trache, L.; Chesneanu, D.; Toma, S.; Ghita, D. G.; Burducea, I.; Margineanu, R.; Pantelica, A.; Gomoiu, C.; Zhang, N. T.; Tang, X.; Li, Y. J.

    2016-04-01

    Heavy-ion fusion reactions between light nuclei such as carbon and oxygen isotopes have been studied because of their significance for a wide variety of stellar burning scenarios. One important stellar reaction is 12C+12C, but it is difficult to measure it in the Gamow window because of very low cross sections and several resonances occurring. Hints can be obtained from the study of 13C+12C reaction. We have measured this process by an activation method for energies down to Ecm=2.5 MeV using 13C beams from the Bucharest 3 MV tandetron and gamma-ray deactivation measurements in our low and ultralow background laboratories, the latter located in a salt mine about 100 km north of Bucharest. Results obtained so far are shown and discussed in connection with the possibility to go even further down in energy and with the interpretation of the reaction mechanism at such deep sub-barrier energies.

  9. Astrophysical S factors for fusion reactions involving C, O, Ne, and Mg isotopes

    SciTech Connect

    Beard, M.; Afanasjev, A.V.; Chamon, L.C.; Gasques, L.R.; Wiescher, M.; Yakovlev, D.G.

    2010-09-15

    Using the Sao Paulo potential and the barrier penetration formalism we have calculated the astrophysical factor S(E) for 946 fusion reactions involving stable and neutron-rich isotopes of C, O, Ne, and Mg for center-of-mass energies E varying from 2 to {approx}18-30 MeV (covering the range below and above the Coulomb barrier). We have parameterized the energy dependence, S(E), by an accurate universal 9-parameter analytic expression and present tables of fit parameters for all the reactions. We also discuss the reduced 3-parameter version of our fit which is highly accurate at energies below the Coulomb barrier, and outline the procedure for calculating the reaction rates. The results can be easily converted to thermonuclear or pycnonuclear reaction rates to simulate various nuclear burning phenomena, in particular, stellar burning at high temperatures and nucleosynthesis in high density environments.

  10. Photo-fusion reactions in a new compact device for ELI

    NASA Astrophysics Data System (ADS)

    Moustaizis, S. D.; Auvray, P.; Hora, H.; Lalousis, P.; Larour, J.; Mourou, G.

    2012-07-01

    In the last few years significant progress on technological, experimental and numerical studies on fusion process in high density and high temperature plasmas produced by a high intensity laser pulse interaction with clusters in a high external applied magnetic field, enable us to propose a compact photo-fusion magnetic device for high neutron production. For the purpose of the project a pulsed magnetic field driver with values up to 110 Tesla has been developed which allows increasing the trapping time of the high density plasma in the device and improving the neutron yield. Numerical simulations show that the proposed device is capable of producing up to 109-1010 neutrons per laser shot with an external magnetic field of 150 Tesla. The proposed device can be used for experiments and numerical code validation concerning different conventional and (or) exotic fusion fuels.

  11. Photo-fusion reactions in a new compact device for ELI

    SciTech Connect

    Moustaizis, S. D.; Auvray, P.; Hora, H.; Lalousis, P.; Larour, J.; Mourou, G.

    2012-07-09

    In the last few years significant progress on technological, experimental and numerical studies on fusion process in high density and high temperature plasmas produced by a high intensity laser pulse interaction with clusters in a high external applied magnetic field, enable us to propose a compact photo-fusion magnetic device for high neutron production. For the purpose of the project a pulsed magnetic field driver with values up to 110 Tesla has been developed which allows increasing the trapping time of the high density plasma in the device and improving the neutron yield. Numerical simulations show that the proposed device is capable of producing up to 10{sup 9}-10{sup 10} neutrons per laser shot with an external magnetic field of 150 Tesla. The proposed device can be used for experiments and numerical code validation concerning different conventional and (or) exotic fusion fuels.

  12. 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.

  13. ICRF-induced DD fusion product losses in TFTR

    SciTech Connect

    Darrow, D.S.; Zweben, S.J.; Budny, R.V.

    1994-10-01

    When ICRF power is applied to TFTR plasmas in which there is no externally-supplied minority species, an enhanced loss of DD fusion products results. The characteristics of the loss are consistent with particles at or near the birth energy having their perpendicular velocity increased by the ICRF such that those near the passing/trapped boundary are carried into the first orbit loss cone. A rudimentary model of this process predicts losses of a magnitude similar to those seen. Extrapolations based upon this data for hypothetical ICRF ash removal from reactor plasmas suggest that the technique will not be energy efficient.

  14. The cost of tritium production in a fusion reactor

    SciTech Connect

    Wittenberg, L.J. . Fusion Technology Inst.)

    1992-03-01

    In this paper, a computational model is presented in order to assess the cost of tritium breeding in a fusion power reactor. This model compares the differential cost of the Li-bearing breeder blanket with that of a steel shield and adds the loss of revenue due to the lower energy multiplication of the breeder blanket compared to the steel shield. The cost of tritium production ranges from $215-$300/g for a simple breeder up to $1420/g for a high temperature breeder.

  15. Quasifission and fusion-fission processes in the reactions 78Kr+40Ca and 86Kr+48Ca at 10 MeV/nucleon bombarding energy

    NASA Astrophysics Data System (ADS)

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

    2016-02-01

    Within the dinuclear system model the charge, mass, and isotopic distributions of the products in the reactions 78Kr+40Ca and 86Kr+48Ca are predicted at bombarding energy 10 MeV/nucleon. The heavy-ion phase-space exploration code is applied to take into consideration the pre-equilibrium emission of light particles. The competition is treated between complete fusion followed by the decay of compound nucleus and quasifission channels. The possible explanation of the odd-even staggering in the yield of the final reaction products at high excitation energies is discussed.

  16. Competition between fusion-fission and quasifission processes in the {sup 32}S+{sup 184}W reaction

    SciTech Connect

    Zhang, H. Q.; Zhang, C. L.; Lin, C. J.; Liu, Z. H.; Yang, F.; Nasirov, A. K.; Mandaglio, G.; Manganaro, M.; Giardina, G.

    2010-03-15

    The angular distributions of fission fragments for the {sup 32}S+{sup 184}W reaction at center-of-mass energies of 118.8, 123.1, 127.3, 131.5, 135.8, 141.1, and 144.4 MeV are measured. The experimental fission excitation function is obtained. The anisotropy (A{sub exp}) is found by extrapolating each fission fragment angular distribution. The measured fission cross sections of the {sup 32}S+{sup 182,184}W reaction are decomposed into fusion-fission, quasifission, and fast-fission contributions by the dinuclear system model (DNS). The angular momentum distributions of the dinuclear system and compound nucleus calculated by the DNS model are used to reproduce the experimental capture and fusion excitation functions for both reactions and quantities K{sub 0}{sup 2}, , and A{sub exp}, which characterize angular distributions of the fission products at the considered range of beam energy. The total evaporation residue excitation function for the {sup 32}S+{sup 184}W reaction calculated in the framework of the advanced statistical model is close to the available experimental data only up to about E{sub c.m.}approx =160 MeV. The underestimation of the experimental data at high excitation energies E{sub c.m.}>160 MeV is explained by the fact that the statistical model cannot reproduce the cross section of evaporation residues formed by the nonequilibrium mechanism, that is, without formation of the compound nucleus in the statistical equilibrium state.

  17. Experimental Study of p-11B Reaction Related to the Clean Fusion Fuel

    NASA Astrophysics Data System (ADS)

    Lin, Erh-kang; Wang, Chang-wan; Yuan, Jian; Liu, Xiao-dong; Li, Cheng-bo; Sun, Zu-xun; Zhang, Pei-hua; Chen, Jin-xiang; Yang, Qi-xiang; Wang, Jian-yong; Ling-hua, Gong

    1998-11-01

    Whole continuous α spectra of the p-11B three-body sequential decay reaction have been measured by using a charge particle time-of-flight (TOF) spectrometer with the high-resolution passivated implanted planar silicon detector. A characteristic shape of the saddle-type distribution was obtained. The Monte Carlo calculations show that observed α spectra can be interpreted by anisotropy sequential decay process of the intermediate nucleus 8Be (1) for the p-11B reaction. In the measurement, angular distributions were obtained for proton energies at 667 and 1370 keV, respectively. Total cross-sections for the 11B(p,α)8Be(2α) reaction related to the clean fusion fuel were also reported at two bombarding energies.

  18. Experimental Studies of Fast Protons Originated from Fusion Reactions in Plasma-Focus Discharges

    SciTech Connect

    Malinowska, A.; Malinowski, K.; Sadowski, M. J.; Zebrowski, J.; Szydlowski, A.

    2008-03-19

    The paper describes results of the recent measurements of fusion-reaction protons, which were performed within the PF-360 facility operated at the IPJ in Swierk, Poland. The main aim of those studies was to perform time-integrated measurements of fast protons (of energy of about 3 MeV) by means of ion-pinhole cameras, which were equipped with solid state nuclear track detectors (SSNTD) of the PM-355 type and absorption filters made of thin metal foils. In order to determine the spatial distribution of fusion-produced protons the use was made of several miniature pinhole cameras placed at different angles to the PF-360 axis. The irradiated and etched detectors were analyzed with an optical microscope coupled with a CCD camera and a PC unit.

  19. Delivery of Therapeutic Proteins as Secretable TAT Fusion Products

    PubMed Central

    Flinterman, Marcella; Farzaneh, Farzin; Habib, Nagy; Malik, Farooq; Gäken, Joop; Tavassoli, Mahvash

    2008-01-01

    The trans-acting activator of transcription (TAT) protein transduction domain (PTD) mediates the transduction of peptides and proteins into target cells. The TAT-PTD has an important potential as a tool for the delivery of therapeutic agents. The production of TAT fusion proteins in bacteria, however, is problematic because of protein insolubility and the absence of eukaryotic post-translational modification. An attractive alternative, both for in vitro protein production and for in vivo applications, is the use of higher eukaryotic cells for secretion of TAT fusion proteins. However, the ubiquitous expression of furin endoprotease (PACE or SPC1) in the Golgi/endoplasmic reticulum, and the presence of furin recognition sequences within TAT-PTD, results in the cleavage and loss of the TAT-PTD domain during its secretory transition through the endoplasmic reticulum and Golgi. In this study, we show the development of a synthetic TATκ-PTD in which mutation of the furin recognition sequences, but retention of protein transduction activity, allows secretion of recombinant proteins, followed by successful uptake of the modified protein, by the target cells. This system was used to successfully secrete marker protein, green fluorescent protein (GFP), and apoptin, a protein with tumor-specific cytotoxicity. Detection of GFP, phosphorylation, and induction of cell death by TATκ-GFP-apoptin indicated that the secreted proteins were functional in target cells. This novel strategy therefore has important potential for the efficient delivery of therapeutic proteins. PMID:19050698

  20. 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.

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

    SciTech Connect

    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.

  2. Gamma-ray emission spectrum from thermonuclear fusion reactions without intrinsic broadening

    NASA Astrophysics Data System (ADS)

    Nocente, M.; Källne, J.; Salewski, M.; Tardocchi, M.; Gorini, G.

    2015-11-01

    First principle calculations of the gamma-ray energy spectrum arising from thermonuclear reactions without intrinsic broadening in fusion plasmas are presented, extending the theoretical framework needed to interpret measurements up to the accuracy level enabled by modern high resolution instruments. An analytical formula for the spectrum from Maxwellian plasmas, which extends to higher temperatures than the results previously available in the literature, has been derived and used to discuss the assumptions and limitations of earlier models. In case of radio-frequency injection, numerical results based on a Monte Carlo method are provided, focusing in particular on improved relations between the peak shift and width from the \\text{d}{{≤ft(\\text{p},γ \\right)}3}\\text{He} reaction and the temperature of protons accelerated by radio-frequency heating. The results presented in this paper significantly improve the accuracy of diagnostic information that can be extracted from the gamma-ray emission spectrum of fusion reactions without intrinsic broadening and are of relevance for applications to high performance plasmas of present and next generation devices.

  3. Cross section systematics for the lightest Bi and Po nuclei produced in complete fusion reactions with heavy ions

    SciTech Connect

    Andreyev, A.N.; Ackermann, D.; Muenzenberg, G.; Antalic, S.; Saro, S.; Streicher, B.; Darby, I.G.; Page, R.D.; Wiseman, D.R.; Franchoo, S.; Hessberger, F.P.; Kuusiniemi, P.; Lommel, B.; Kindler, B.; Mann, R.; Sulignano, B.; Hofmann, S.; Huyse, M.; Vel, K. van de; Duppen, P. van

    2005-07-01

    The production of the very neutron-deficient nuclides {sup 184-192}Bi and {sup 186-192}Po in the vicinity of the neutron midshell at N = 104 has been studied by using heavy-ion-induced complete fusion reactions in a series of experiments at the velocity filter SHIP. The cross sections for the xn and pxn evaporation channels of the {sup 46}Ti+{sup 144}Sm{yields}{sup 190}Po*,{sup 98}Mo+{sup 92}Mo{yields}{sup 190}Po*,{sup 50,52}Cr+{sup 142}Nd{yields}{sup 192,194}Po*, and {sup 94,95}Mo+{sup 93}Nb{yields}{sup 187,188}Bi* reactions were measured. The results obtained, together with the previously known cross section data for the heavier Bi and Po nuclides, are compared with the results of statistical model calculations carried out with the HIVAP code. It is shown that a satisfactory description of the experimental data requires a significant (up to 35%) reduction of the theoretical fission barriers. The optimal reactions for production of the lightest Bi and Po isotopes are discussed.

  4. Optimizing Neutron Production Rates from D-D Fusion in an Inertial Electrostatic Confinement Device

    SciTech Connect

    Wehmeyer, A.L.; Radel, R.F.; Kulcinski, G.L.

    2005-05-15

    Detection of explosives has been identified as a near term commercial opportunity for using a fusion plasma. Typical explosive compositions contain low Z material (C, N, O) which are not easily detected using conventional x-rays or metal detectors. However, 2.45 MeV neutrons produced in a D-D fusion reaction can be used for detection of explosives or other clandestine materials in suitcases, packages, or shipping containers.Steady-state D-D operation is possible using an Inertial Electrostatic Confinement (IEC) fusion device. The University of Wisconsin IEC device has produced D-D neutrons at 1.8 x 10{sup 8} neutrons/second at a true cathode voltage of 166 kV and a meter current of 68 mA. These neutron production rates are approaching the levels required for the detection of explosives. In order to increase and optimize the neutron production rate in the IEC device, experiments were performed altering the cathode's size (diameter), geometry, and material composition. Preliminary results indicate that significant differences in neutron production rates are not achieved by altering the geometry or material composition of the cathode. However, the neutron production rate was found to increase approximately 20% by doubling the cathode's diameter from 10 cm to 20 cm. In addition, increasing the cathode voltage from 34 kV to 94 kV at a meter current of 30 mA increased the neutron production rate from 1.24 x 10{sup 6} n/s to 2.83 x 10{sup 7} n/s.

  5. Fission barriers for Po nuclei produced in complete fusion reactions with heavy ions

    SciTech Connect

    Sagaidak, R. N.; Andreyev, A. N.

    2009-05-15

    Evaporation residues and fission excitation functions obtained in complete fusion reactions leading to Po compound nuclei have been analyzed in the framework of the standard statistical model. Macroscopic fission barriers deduced from the cross-section data analysis are compared with the predictions of various theoretical models and available data. A drop in the Po barriers with the decrease in a neutron number was found, which is stronger than predicted by any theory. The presence of entrance channel effects and collective excitations in the compound nucleus decay is considered as a possible reason for the barrier reduction.

  6. Physics of laser-plasma interaction for shock ignition of fusion reactions

    NASA Astrophysics Data System (ADS)

    Tikhonchuk, V. T.; Colaïtis, A.; Vallet, A.; Llor Aisa, E.; Duchateau, G.; Nicolaï, Ph; Ribeyre, X.

    2016-01-01

    The shock ignition scheme is an alternative approach, which aims to achieve ignition of fusion reactions in two subsequent steps: first, the target is compressed at a low implosion velocity and second, a strong converging shock is launched during the stagnation phase and ignites the hot spot. In this paper we describe the major elements of this scheme and recent achievements concerning the laser-plasma interaction, the crucial role of hot electrons in the shock generation, the shock amplification in the imploding shell and the ignition conditions.

  7. Quantum description of coupling to neutron-rearrangement channels in fusion reactions near the Coulomb barrier

    SciTech Connect

    Samarin, V. V.

    2015-10-15

    The fusion cross sections for the {sup 17,18}O+{sup 27}Al, {sup 18}O+{sup 58}Ni, and {sup 6}He+{sup 197}Au reactions were calculated by the coupled-channel method. The radial dependence of matrices that describe coupling to valence-neutron-rearrangement channels was determined with the aid of two-center wave functions. The coupling-strength parameters were evaluated on the basis of numerically solving the time-dependent Schrödinger equation. Satisfactory agreement with experimental data was obtained.

  8. Present status of coupled-channels calculations for heavy-ion subbarrier fusion reactions

    NASA Astrophysics Data System (ADS)

    Hagino, K.; Yao, J. M.

    2016-05-01

    The coupled-channels method has been a standard tool in analyzing heavy-ion fusion reactions at energies around the Coulomb barrier. We investigate three simplifications usually adopted in the coupledchannels calculations. These are i) the exclusion of non-collective excitations, ii) the assumption of coordinate independent coupling strengths, and iii) the harmonic oscillator approximation for multiphonon excitations. In connection to the last point, we propose a novel microscopic method based on the beyond-mean-field approach in order to take into account the anharmonic effects of collective vibrations.

  9. Utility of spectral measurements of secondary reaction products

    SciTech Connect

    Heidbrink, W.E.

    1986-02-01

    The spectra of 15 MeV protons and 14 MeV neutrons produced in the burnup of 0.8 MeV THe ions and 1 MeV tritons through the d(THe,p) and d(t,n) fusion reactions contain information on the velocity distributions of the energetic THe ions and tritons. 11 refs., 2 figs.

  10. Fusion and binary reactions in the collision of /sup 32/S on /sup 26/Mg at /ital E//sub lab/=163. 5 MeV

    SciTech Connect

    Cavallaro, S.; Zhi, Y. S.; Prete, G.; Viesti, G.

    1989-07-01

    Measurements of heavy fragments produced in the interaction of /sup 32/S with /sup 26/Mg at /ital E//sub lab/=163.5 MeV have been performed to study the interplay of the fusion reaction and binary processes. Experimental angular distributions, velocity spectra, and angle-integrated cross sections of detected heavy fragments have been compared with predictions of statistical models. The comparison shows that complete fusion exhausts the production of residues in the range /ital Z/=26--22. For fragments with atomic number /ital Z/=21 and /ital Z/=20 some other mechanism is also present. The analysis of energy spectra, angular distributions, and total kinetic energy of projectile-like fragments (/ital Z/=19--6) shows that the main process to limit fusion is an inelastic mechanism with large energy damping.

  11. Production of Medical isotope Technecium-99 from DT Fusion neutrons

    NASA Astrophysics Data System (ADS)

    Boguski, John; Gentile, Charles; Ascione, George

    2011-10-01

    High energy neutrons produced in DT fusion reactors have a secondary application for use in the synthesis of valuable man-made isotopes utilized in industry today. One such isotope is metastable Technecium-99 (Tc99m), a low energy gamma emitter used in ~ 85% of all medical imaging diagnostics. Tc99m is created through beta decay of Molybdenum-99 (Mo99), which itself has only a 66 hour half-life and must be created from a neutron capture by the widely available and stable isotope Molydenum-98. Current worldwide production of Tc99m occurs in just five locations and relies on obtaining the fission byproduct Mo99 from highly enriched Uranium reactors. A Tc99m generator using DT fusion neutrons, however, could potentially be operated at individual hospitals and medical facilities without the use of any fissile material. The neutron interaction of the DT neutrons with Molybdenum in a potential device geometry was modeled using Monte Carlo neutron transport code MCNP. Trial experiments were also performed to test the viability of using DT neutrons to create ample quantities of Tc99m. Modeling and test results will follow.

  12. Instability of the Contained Mode Due to Fusion Product Interactions

    NASA Astrophysics Data System (ADS)

    Riconda, C.; Coppi, B.; Penn, G.

    1996-11-01

    We study a model(C. Riconda, G. Penn, B. Coppi, 1996 International Sherwood Fusion Theory Conference, PPPL (Princeton University). Paper#2C39 ) that explains the main characteristics of enhanced ion cyclotron emission in fusing plasmas. In particular, the radiation peaks occur at harmonics of the α (or D) cyclotron frequency at the outer edge of the plasma column(JET Team, Phys. of Fluids \\underbar B5) (1993) 3 . In this model, the radiation results from the excitation of radially ``contained''(B. Coppi, Phys. Lett. A \\underbar 172) (1993) 439 modes, treated in a cylindrical approximation, which are driven unstable by the fusion products. The growth rate is evaluated using a full toroidal calculation for particle dymanics, and depends linearly on the α-particle density. The ``contained'' modes of this model are sharply localized in radius, compared to the radial excursion of the trapped particle orbits. In the limit where the growth rate is larger than the orbital frequency, this allows the calculation of the growth rate in the WKB approximation, where all quantities are evaluated at the mode layer and radial derivatives are neglected. We show the dependence of the growth rate on Larmor radius, toroidal effects (including drifts), and anisotropy in velocity space.

  13. Simulation of Carbon Production from Material Surfaces in Fusion Devices

    NASA Astrophysics Data System (ADS)

    Marian, J.; Verboncoeur, J.

    2005-10-01

    Impurity production at carbon surfaces by plasma bombardment is a key issue for fusion devices as modest amounts can lead to excessive radiative power loss and/or hydrogenic D-T fuel dilution. Here results of molecular dynamics (MD) simulations of physical and chemical sputtering of hydrocarbons are presented for models of graphite and amorphous carbon, the latter formed by continuous D-T impingement in conditions that mimic fusion devices. The results represent more extensive simulations than we reported last year, including incident energies in the 30-300 eV range for a variety of incident angles that yield a number of different hydrocarbon molecules. The calculated low-energy yields clarify the uncertainty in the complex chemical sputtering rate since chemical bonding and hard-core repulsion are both included in the interatomic potential. Also modeled is hydrocarbon break-up by electron-impact collisions and transport near the surface. Finally, edge transport simulations illustrate the sensitivity of the edge plasma properties arising from moderate changes in the carbon content. The models will provide the impurity background for the TEMPEST kinetic edge code.

  14. Fusion

    NASA Astrophysics Data System (ADS)

    Herman, Robin

    1990-10-01

    The book abounds with fascinating anecdotes about fusion's rocky path: the spurious claim by Argentine dictator Juan Peron in 1951 that his country had built a working fusion reactor, the rush by the United States to drop secrecy and publicize its fusion work as a propaganda offensive after the Russian success with Sputnik; the fortune Penthouse magazine publisher Bob Guccione sank into an unconventional fusion device, the skepticism that met an assertion by two University of Utah chemists in 1989 that they had created "cold fusion" in a bottle. Aimed at a general audience, the book describes the scientific basis of controlled fusion--the fusing of atomic nuclei, under conditions hotter than the sun, to release energy. Using personal recollections of scientists involved, it traces the history of this little-known international race that began during the Cold War in secret laboratories in the United States, Great Britain and the Soviet Union, and evolved into an astonishingly open collaboration between East and West.

  15. Production of pesticide metabolites by oxidative reactions.

    PubMed

    Hodgson, E

    1982-08-01

    The cytochrome P-450-dependent monooxygenase system catalyzes a wide variety of oxidations of pesticide chemicals and related compounds. These reactions include epoxidation and aromatic hydroxylation, aliphatic hydroxylation, O-, N- and S-dealkylation, N-oxidation, oxidative deamination, S-oxidation, P-oxidation, desulfuration and ester cleavage and may result in either detoxication or activation of the pesticide. The current status of such reactions, relative to the production, in vivo, of biologically active intermediates in pesticide metabolism is summarized. More recently we have shown that the FAD-containing monooxygenase of mammalian liver (E.C.1.14.13.8), a xenobiotic metabolizing enzyme of broad specificity formerly known as an amine oxidase, is involved in a variety of pesticide oxidations. These include sulfoxidation of organophosphorus insecticides such as phorate and disulfoton, oxidative desulfuration of phosphonate insecticides such as fonofos and oxidation at the phosphorus atom in such compounds as the cotton defoliant, folex. The relative importance of the FAD-containing monooxygenase vis-a-vis the cytochrome P-450-dependent monooxygenase system is discussed, based on in vitro studies on purified enzymes. PMID:7161848

  16. Reactions of uranium hexafluoride photolysis products

    NASA Astrophysics Data System (ADS)

    Lyman, John L.; Laguna, Glenn; Greiner, N. R.

    1985-01-01

    This paper confirms that the ultraviolet photolysis reactions of UF6 in the B band spectral region is simple bond cleavage to UF5 and F. The photolysis products may either recombine to UF6 or the UF5 may dimerize, and ultimately polymerize, to solid UF5 particles. We use four methods to set an upper limit for the rate constant for recombination of kr<2.0×10-12cm3 molecule-1 s-1. We measure the rate constant for UF5 dimerization to be kd=(1.0±0.2)×10-11 cm3 molecule-1 s-1. The principal method employed in these studies is the use of diode lasers to monitor, in real time, the changes in density of the species UF6 and UF5 after laser photolysis of the UF6 gas sample.

  17. Measurements of 10B(p,a)7Be Cross-sections: A Reaction Relevant to Nuclear Fusion Energy Research

    NASA Astrophysics Data System (ADS)

    Fisher, Barbara; Kafkarkou, Adamos; Ahmed, Mohammad; Weller, Henry; Myers, Luke; Sparker, Mark; Zimmerman, William; Mueller, Jon; Sikora, Mark; Mazumdar, Indral

    2012-10-01

    There is growing interest in aneutronic nuclear fusion reactors. One facility proposes to utilize the 11B(p,a)7Be reaction. The Radiative Capture Group at Triangle University Nuclear Laboratory (TUNL) has been engaged in a long-term study of this and related reactions. This poster will present preliminary data and analysis of the 10B(p,a)7Be reaction which is of interest because 10B is a potential reactor contaminant. Differential and total cross-sections will be presented for incident protons of 4.4 and 4.6 MeV. The data is necessary for simulations of an aneutrionic nuclear fusion reactor.

  18. Fusion and neutron transfer reactions with weakly bound nuclei within time-dependent and coupled channel approaches

    NASA Astrophysics Data System (ADS)

    Samarin, V. V.

    2016-05-01

    The time-dependent Schrödinger equation and the coupled channel approach based on the method of perturbed stationary two-center states are used to describe nucleon transfers and fusion in low-energy nuclear reactions. Results of the cross sections calculation for the formation of the 198Au and fusion in the 6He+197Au reaction and for the formation of the 65Zn in 6He+64Zn reaction agree satisfactorily with the experimental data near the barrier. The Feynman's continual integrals calculations for a few-body systems were used for the proposal of the new form of the shell model mean field for helium isotopes.

  19. Fusion Probability in the Reactions {sup 58}Fe+{sup 244}Pu and {sup 64}Ni+{sup 238}U

    SciTech Connect

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

    2010-04-30

    Mass-energy distributions, as well as capture cross-section of fission-like fragments for the reactions {sup 64}Ni+{sup 238}U and {sup 58}Fe+{sup 244}Pu leading to the formation of superheavy compound system with Z = 120 and N 182 at energies near the Coulomb barrier have been measured. Fusion-fission cross sections were estimated from the analysis of mass and total kinetic energy distributions. It was found that the fusion probability is about one order of magnitude higher for the reaction {sup 58}Fe+{sup 244}Pu than that for the reaction with {sup 64}Ni-ions.

  20. An overview on incomplete fusion reaction dynamics at energy range ∼ 3-8 MeV/A

    SciTech Connect

    Ali, Rahbar; Singh, D.; Ansari, M. Afzal; Kumar, Rakesh; Muralithar, S.; Golda, K. S.; Singh, R. P.; Bhowmik, R. K.; Rashid, M. H.; Guin, R.; Das, S. K.

    2014-08-14

    The information of ICF reaction has been obtained from the measurement of excitation function (EF) of ERs populated in the interaction of {sup 20}Ne and {sup 16}O on {sup 55}Mn, {sup 159}Tb and {sup 156}Gd targets. Sizable enhancement in the measured cross-sections has been observed in α-emitting channels over theoretical predictions, which has been attributed to ICF of the projectile. In order to confirm the findings of the measurements and analysis of EFs, the forward recoil range distributions of ERs populated in {sup 20}Ne+{sup 159}Tb (E ∼165MeV) and {sup 16}O+{sup 156}Gd (E ∼ 72, 82 and 93MeV) systems, have been measured. It has been observed that peaks appearing at different cumulative thicknesses in the stopping medium are related with different degree of linear momentum transfer from projectile to target nucleus by adopting the break-up fusion model consideration. In order to deduce the angular momentum involved in various CF and / or ICF reaction products, spin distribution and side-feeding intensity profiles of radio-nuclides populated via CF and ICF channels in {sup 16}O+{sup 160}Gd system at energy, E ∼ 5.6 MeV/A, have been studied. Spin distribution of ICF products are found to be distinctly different than that observed from CF products.

  1. Dynamical Dipole Mode in Heavy-Ion Fusion-Evaporation and Fission Reactions in the {sup 192}Pb Mass Region

    SciTech Connect

    Silvestri, R.; Inglima, G.; La Commara, M.; Martin, B.; Sandoli, M.; Pierroutsakou, D.; Parascandolo, C.; Boiano, A.; Romoli, M.; Agodi, C.; Alba, R.; Colonna, M.; Coniglione, R.; Del Zoppo, A.; Maiolino, C.; Santonocito, D.; Baran, V.; De Filippo, E.; Di Toro, M.; Rizzo, C.

    2011-10-28

    The prompt {gamma}-ray emission related with the dynamical dipole mode decay was investigated in the {sup 192}Pb mass region by means of the {sup 40}Ca+{sup 152}Sm and {sup 48}Ca+{sup 144}Sm fusion-evaporation and fission reactions at E{sub lab} = 11 and 10.1 MeV/nucleon, respectively. The two reactions populate, through entrance channel having different charge asymmetries, the {sup 192}Pb compound nucleus at an excitation energy of 236 MeV with identical spin distribution. Preliminary results of this experiment show that the dynamical dipole mode survives in collisions involving heavier mass reaction partners than those studied previously. As a fast cooling mechanism on the fusion path, the prompt dipole {gamma} radiation could be of interest for the synthesis of super-heavy elements through ''hot'' fusion reactions.

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

    SciTech Connect

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

    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 among 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.

  3. Advanced scheme for high-yield laser driven proton-boron fusion reaction

    NASA Astrophysics Data System (ADS)

    Margarone, D.; Picciotto, A.; Velyhan, A.; Krasa, J.; Kucharik, M.; Morrissey, M.; Mangione, A.; Szydlowsky, A.; Malinowska, A.; Bertuccio, G.; Shi, Y.; Crivellari, M.; Ullschmied, J.; Bellutti, P.; Korn, G.

    2015-02-01

    A low contrast nanosecond laser pulse with relatively low intensity (3 × 1016 W cm-2) was used to enhance the yield of induced nuclear reactions in advanced solid targets. In particular the "ultraclean" proton-boron fusion reaction, producing energetic alpha-particles without neutron generation, was chosen. A spatially well-defined layer of boron dopants in a hydrogen-enriched silicon substrate was used as target. The combination of the specific target geometry and the laser pulse temporal shape allowed enhancing the yield of alpha-particles up to 109 per steradian, i.e 100 times higher than previous experimental achievements. Moreover the alpha particle stream presented a clearly peaked angular and energy distribution, which make this secondary source attractive for potential applications. This result can be ascribed to the interaction of the long laser pre-pulse with the target and to the optimal target geometry and composition.

  4. Gluon-fusion contributions to {Phi}+2 jet production

    SciTech Connect

    Campanario, F.; Zeppenfeld, D.; Kubocz, M.

    2011-11-01

    In high energy hadronic collisions, a scalar or pseudoscalar Higgs boson, {Phi}=H, A, can be efficiently produced via gluon fusion, which is mediated by heavy quark loops. In this paper, we consider double real emission corrections to {Phi}=A production, which lead to a Higgs plus two-jet final state, at order {alpha}{sub s}{sup 4}. Full quark mass effects are considered in the calculation of scattering amplitudes for the CP-odd Higgs boson A, as induced by quark triangle-, box-, and pentagon-diagrams. They complement the analogous results for a CP-even Higgs boson H in Ref. [1]. Interference effects between loops with top and bottom quarks as well as between CP-even and CP-odd couplings of the heavy quarks are fully taken into account.

  5. Fokker-Planck Modelling of Delayed Loss of Charged Fusion Products in TFTR.

    SciTech Connect

    Edenstrasser, J.W.; Goloborod'ko, V.Ya.; Reznik, S.N.; Yavorskij, V.A.; Zweben, S.

    1998-08-01

    The results of a Fokker-Planck simulation of the ripple-induced loss of charged fusion products in the Tokamak Fusion Test Reactor (TFTR) are presented. It is shown that the main features of the measured "delayed loss" of partially thermalized fusion products, such as the differences between deuterium-deuterium and deuterium-tritium discharges, the plasma current and major radius dependencies, etc., are in satisfactory agreement with the classical collisional ripple transport mechanism. The inclusion of the inward shift of the vacuum flux surfaces turns out to be necessary for an adequate and consistent explanation of the origin of the partially thermalized fusion product loss to the bottom of TFTR.

  6. Electroweak meson production reaction in the nucleon resonance region

    SciTech Connect

    Sato, Toru

    2015-10-15

    We report on our recent study of the the neutrino-nucleon reaction in the nucleon resonance region. The dynamical reaction model of meson production reaction on the nucleon for the pion and photon induced reaction has been developed in order to investigate the spectrum of nucleon excited state. We have extended this model in order to describe the weak meson production reactions with the πN, ηN, KΛ, KΣ and ππN final states. We also studied the role of the final state interaction in the photon and the neutrino induced pion production reaction on the deuteron around the Δ(1232) resonance region.

  7. Detailed determination of the nuclear fusion radius by a simultaneous optical model calculation of elastic scattering and fusion cross sections in reactions involving weakly bound projectiles

    SciTech Connect

    Camacho, A. Gomez; Aguilera, E. F.; Gomes, P. R. S.; Lubian, J.

    2007-10-15

    Within the optical model for direct reactions, simultaneous calculations of elastic scattering, complete fusion, and total reaction cross sections for energies around the Coulomb barrier are presented for reactions involving the weakly bound projectile {sup 9}Be on {sup 64}Zn. Volume (W{sub F}) and surface (W{sub DR}) Woods-Saxon optical potentials are used such that the former is responsible only for complete fusion reactions while the latter for all direct reactions plus incomplete fusion. Simultaneous fits can be obtained with several sets of potential parameters, but if we impose the condition that the strength of W{sub F} is smaller than the strength of W{sub DR} at the tail region of the potential (this condition is discussed in detail), then values are required for r{sub F} and r{sub DR} of around 1.6 and 1.7-1.9 fm, respectively. These values are much larger than those frequently used in barrier penetration model calculations. Through the energy dependence of the real and imaginary parts of the polarization potentials, we show that the usual threshold anomaly does not show up for this system, but instead there is evidence of the presence of a breakup threshold anomaly.

  8. Charge-exchange reaction by Reggeon exchange and W{sup +}W{sup −}-fusion

    SciTech Connect

    Schicker, R.

    2015-04-10

    Charge-exchange reactions at high energies are examined. The existing cross section data on the Reggeon induced reaction pp → n + Δ{sup ++} taken at the ZGS and ISR accelerators are extrapolated to the energies of the RHIC and LHC colliders. The interest in the charge-exchange reaction induced by W{sup ±}-fusion is presented, and the corresponding QCD-background is examined.

  9. 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.

  10. (γ,2n) Reaction Cross Section Calculations on Several Structural Fusion Materials

    NASA Astrophysics Data System (ADS)

    Kaplan, A.; Özdoğan, H.; Aydın, A.; Tel, E.

    2013-08-01

    In this study, the theoretical photo-neutron cross-sections produced by (γ,2n) reactions for several structural fusion materials such as 51V, 55Mn, 58Ni, 90,91,92,94Zr, and 181Ta have been carried out for incident photon energies up to 40 MeV. Reaction cross-sections as a function of photon energy have been calculated theoretically using the PCROSS and TALYS 1.2 computer codes. TALYS 1.2 default and pre-equilibrium models have been used to calculate the pre-equilibrium photo-neutron cross-sections. For the reaction equilibrium component, PCROSS Weisskopf-Ewing model calculations have been preferred. The calculated results have been compared with each other and against the experimental data in the existing databases EXFOR. Generally, TALYS 1.2 default and pre-equilibrium model cross-section calculations are in good agreement with the experimental data for all reactions along the incident photon energy in this study. Pre-equilibrium option can be recommended, if experimental data are not available or are unlikely to be produced due to the experimental difficulty.

  11. Fusion cross sections for the {sup 9}Be+{sup 124}Sn reaction at energies near the Coulomb barrier

    SciTech Connect

    Parkar, V. V.; Palit, R.; Sharma, Sushil K.; Naidu, B. S.; Santra, S.; Mahata, K.; Ramachandran, K.; Joshi, P. K.; Rath, P. K.; Trivedi, T.; Raghav, A.

    2010-11-15

    The complete and incomplete fusion cross sections for {sup 9}Be+{sup 124}Sn reaction have been deduced using the online {gamma}-ray measurement technique. Complete fusion at energies above the Coulomb barrier was found to be suppressed by {approx}28% compared to the coupled-channels calculations and is in agreement with the systematics of L. R. Gasques et al. [Phys. Rev. C 79, 034605 (2009)]. Study of the projectile dependence for fusion on a {sup 124}Sn target shows that, for {sup 9}Be nuclei, the enhancement at below-barrier energies is substantial compared to that of tightly bound nuclei.

  12. Economic requirements for competitive laser fusion power production

    SciTech Connect

    Hogan, W.J.; Meier, W.R.

    1985-11-15

    An economic model of a laser fusion commercial power plant is used to identify the design and operating regimes of the driver, target and reaction chamber that will result in economic competitiveness with future fission and coal plants. We find that, for a plant with a net power of 1 GW/sub e/, the cost of the driver must be less than $0.4 to 0.6 B, and the recirculating power fraction must be less than 25%. Target gain improvements at low driver energy are the most beneficial but also the most difficult to achieve. The optimal driver energy decreases with increasing target technology. The sensitivity of the cost of electricity to variations in cost and performance parameters decreases with increasing target technology. If chamber pulse rates of a few Hz can be achieved, then gains of 80 to 100 will be sufficient, and higher pulse rates do not help much. Economic competitiveness becomes more difficult with decreasing plant size. Finally, decreasing the cost of the balance of plant has the greatest beneficial effect on economic competitiveness. 6 refs., 5 figs., 2 tabs.

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

    SciTech Connect

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

    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 on 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.

  14. Influence of the neutron numbers of projectile and target on the evaporation residue cross sections in hot fusion reactions

    NASA Astrophysics Data System (ADS)

    Zhu, Long; Su, Jun; Zhang, Feng-Shou

    2016-06-01

    Within the framework of a dinuclear system model, the influence of projectile and target neutron number on capture cross section, fusion probability, and survival probability for the reactions S,3634+238U and 48Ca+Pu 239 ,240 ,242 ,244 are investigated. The calculated excitation functions are in good agreement with the experimental data. To synthesize more unknown neutron-deficient isotopes of already-known superheavy elements, the possibility of using lighter calcium isotopes to induce hot fusion reactions is investigated and the maximal evaporation residual cross sections for Ca 44 ,46 ,48 -induced hot fusion reactions to produce unknown neutron-deficient superheavy nuclei with Z =112 -116 are predicted.

  15. Comparative analysis of anodized, implanted and sputtered tantalum oxide targets for the study of 16O+16O fusion reaction

    NASA Astrophysics Data System (ADS)

    Silva, H.; Cruz, J.; Redondo-Cubero, A.; Santos, C.; Fonseca, M.; Luis, H.; Jesus, A. P.

    2014-07-01

    Measuring the total cross section of a fusion reaction in the region of astrophysical interest, such as the 16O+16O fusion reaction, is a real challenge due the very small cross sections involved and the large number of possible exit channels. Taking into account these difficulties, the use of targets with known thickness, stoichiometry and minimal contamination that can withstand high beam currents is required. In this study, we report the comparison between three different types of targets for the study of this fusion reaction, such as anodized, implanted and sputtered tantalum oxide targets and the results show that the anodized and sputtered targets are more suitable for this study due to their higher oxygen density and to the formation of a stable oxide compound, tantalum pentoxide (Ta2O5).

  16. Fusion, and advanced-fuel, reaction bibliography. Particle reactions from H1 to B11. Special report, 17 February-17 August 1987

    SciTech Connect

    Pass, H.H.

    1987-08-01

    The Air Force Astronautics Laboratory has an ongoing program of studying the feasibility of fusion powered propulsion. This study first examines nuclear fuels and their associated fuel cycles. The investigated fuels and fuel cycles will then be used to explore present and proposed fusion propulsion concepts. From this study, it will be determined which concepts, if any, will be able to produce fusion propulsion systems using present or near term technology. The objective of the work reported herein was to compile a comprehensive list of the experimentally measured nuclear reactions involving the nuclides up to and including B11 (Boron-11). This compilation was performed in order to identify any new fuels and/or fuel cycles that would be potential candidate to replace the presently utilized fuels deuterium and tritium. Also, the project is intended to provide a readily accessible source of information for individuals who are studying fuels, reactions, and fuel cycles.

  17. Energy distribution among reaction products. V.

    NASA Technical Reports Server (NTRS)

    Anlauf, K. G.; Horne, D. S.; Macdonald, R. G.; Polanyi, J. C.; Woodall, K. B.

    1972-01-01

    Discussion of three reactions, one point of theoretical interest being the predicted correlation between barrier height and barrier location. The H + Br 2 reaction having a lower activation barrier than H + Cl 2, should have an earlier barrier, and hence a greater percentage attractive energy release and higher efficiency of vibrational excitation. Information is developed concerning the effect of isotopic substitution in the pair of reactions H + Cl 2 and D + Cl 2. The 'arrested relaxation' method was used. Essentially, the method involves reacting two diffuse reagent beams in a reaction vessel with background pressure less than 0.001 torr, and with walls cooled by liquid nitrogen or liquid helium.

  18. 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.

  19. Productive Hemifusion Intermediates in Fast Vesicle Fusion Driven by Neuronal SNAREs

    PubMed Central

    Liu, Tingting; Wang, Tingting; Chapman, Edwin R.; Weisshaar, James C.

    2008-01-01

    An in vitro fusion assay uses fluorescence microscopy of labeled lipids to monitor single v-SNARE vesicle docking and fusion events on a planar lipid bilayer containing t-SNAREs. For vesicles and bilayer comprising phosphatidylcholine (POPC, 84–85% by mol) and phosphatidylserine (DOPS, 15% by mol), previous work demonstrated prompt, full fusion (τfus = 25 ms). Substitution of 20–60% phosphatidylethanolamine (DOPE) for phosphatidylcholine in the v-SNARE vesicle with either 0 or 20% DOPE included in the t-SNARE bilayer gives rise to hemifusion events. Labeled lipids diffuse into the planar bilayer as two temporally distinct waves, presumably hemifusion of the outer leaflet followed by inner leaflet (core) fusion. The fusion kinetics with DOPE is markedly heterogeneous. Some vesicle/docking site pairs exhibit prompt, full fusion while others exhibit hemifusion. Hemifusion events are roughly half productive (leading to subsequent core fusion within 20 s) and half dead-end. In qualitative accord with expectations from studies of protein-free vesicle-vesicle fusion, the hemifusion rate khemi is 15–20 times faster than the core fusion rate kcore, and the fraction of hemifusion events increases with increasing percentage of DOPE. This suggests similar underlying molecular pathways for protein-free and neuronal SNARE-driven fusion. Removal of phosphatidylserine from the v-SNARE vesicle has no effect on docking or fusion. PMID:17951297

  20. Reaction-Based SiC Materials for Joining Silicon Carbide Composites for Fusion Energy

    SciTech Connect

    Lewinsohn, Charles A.; Jones, Russell H.; Singh, M.; Serizawa, H.; Katoh, Y.; Kohyama, A.

    2000-09-01

    The fabrication of large or complex silicon carbide-fiber-reinforced silicon carbide (SiC/SiC) components for fusion energy systems requires a method to assemble smaller components that are limited in size by manufacturing constraints. Previous analysis indicates that silicon carbide should be considered as candidate joint materials. Two methods to obtain SiC joints rely on a reaction between silicon and carbon to produce silicon carbide. This report summarizes preliminary mechanical properties of joints formed by these two methods. The methods appear to provide similar mechanical properties. Both the test methods and materials are preliminary in design and require further optimization. In an effort to determine how the mechanical test data is influenced by the test methodology and specimen size, plans for detailed finite element modeling (FEM) are presented.

  1. Analytical criterion for shock ignition of fusion reaction in hot spot

    NASA Astrophysics Data System (ADS)

    Ribeyre, X.; Tikhonchuk, V. T.; Breil, J.; Lafon, M.; Vallet, A.; Le Bel, E.

    2013-11-01

    Shock ignition of DT capsules involves two major steps. First, the fuel is assembled by means of a low velocity conventional implosion. At stagnation, the central core has a temperature lower than the one needed for ignition. Then a second, strong spherical converging shock, launched from a high intensity laser spike, arrives to the core. This shock crosses the core, rebounds at the target center and increases the central pressure to the ignition conditions. In this work we consider this latter phase by using the Guderley self-similar solution for converging flows. Our model accounts for the fusion reaction energy deposition, thermal and radiation losses thus describing the basic physics of hot spot ignition. The ignition criterion derived from the analytical model is successfully compared with full scale hydrodynamic simulations.

  2. A Prospect on the Demonstration of Electric Power Production from Fusion Energy

    NASA Astrophysics Data System (ADS)

    Okano, Kunihiko; Ogawa, Yuichi; Tobita, Kenji

    This paper describes a prospect toward electric power production by the Fusion energy. In the first part of the paper, a principle of TOKAMAK system which is the successful magnetic-confinement-systems for fusion reactors are shown, and then the ITER project based on TOKAMAK and the present status of ITER is reviewed. In the remainder of the paper, a roadmap for fusion energy and conceptual designs of Demonstration reactors are briefly described.

  3. Inertial fusion: an energy-production option for the future

    SciTech Connect

    Hovingh, J.; Pitts, J.H.; Monsler, M.J.; Grow, G.R.

    1982-05-01

    The authors discuss the inertial-confinement approach to fusion energy. After explaining the fundamentals of fusion, they describe the state of the art of fusion experiments, emphasizing the results achieved through the use of neodymium-doped glass lasers at Lawrence Livermore National Laboratory and at other laboratories. They highlight recent experimental results confirming theoretical predictions that short-wavelength lasers have excellent energy absorption on fuel pellets. Compressions of deuterium-tritium fuel of over 100 times liquid density have been measured, only a factor of 10 away from the compression required for a commercial reactor. Finally, it is shown how to exploit the unique characteristics of inertial fusion to design reactor chambers that have a very high power density and a long life, features that the authors believe will eventually lead to fusion power at a competitive cost.

  4. Investigation of the role of break-up processes on the fusion of {sup 16}O induced reactions

    SciTech Connect

    Singh, Devendra P.; Unnati; Singh, Pushpendra P.; Yadav, Abhishek; Singh, B. P.; Prasad, R.; Sharma, Manoj Kumar; Golda, K. S.; Kumar, Rakesh; Sinha, A. K.

    2009-07-15

    An experiment was carried out to explore heavy ion incomplete fusion reaction dynamics, within the framework of the break-up fusion model, at energies near and above the Coulomb barrier. Excitation functions for several radionuclides produced via xn, pxn, and {alpha}xn channels were measured in the {sup 16}O+{sup 181}Ta system at energies of {approx_equal}76-100 MeV. The experimental excitation functions were compared with those calculated using the theoretical model code PACE4. It was observed that excitation functions of xn/pxn channels are in good agreement with theoretical predictions. However, a significant enhancement in the measured excitation functions of {alpha}-emitting channels was observed and attributed to the incomplete fusion processes. The incomplete fusion fraction (F{sub ICF}) that gives the relative importance of complete and incomplete fusion processes was found to increase with energy. The results are discussed in terms of {alpha}-cluster structure of the projectile on various fusion reactions.

  5. Incomplete-fusion reactions for {gamma}-ray spectroscopy: Application to the study of high-spin states in {sup 234}U

    SciTech Connect

    Lane, G. J.; Dracoulis, G. D.; Byrne, A. P.; McGoram, T. R.; Poletti, A. R.

    1999-09-02

    Incomplete-fusion reactions occur when breakup of the projectile results in only part of the beam particle fusing with the target, the remnant being emitted with an energy equivalent to the beam velocity. Such reactions have been demonstrated to populate slightly neutron-rich nuclei compared to conventional fusion-evaporation reactions, opening possibilities for the study of nuclei along the neutron-rich side of the line of stability. Results from a study of {sup 211}Po are presented to illustrate the use of incomplete-fusion reactions for {gamma}-ray spectroscopy. New results from a test-run which populated high-spin states in {sup 234}U via the {sup 232}Th({sup 9}Be,{alpha}3n) reaction are also presented. An interesting feature of the latter reaction is that the high fission probabilities for the compound nuclei which follow complete fusion, results in the residues from incomplete fusion forming the dominant residue channels.

  6. Production of hollow microspheres for inertial confinement fusion experiments

    SciTech Connect

    Cook, R.

    1994-12-01

    The targets used in inertial confinement fusion (ICF) experiments at the Lawrence Livermore National Laboratory are plastic capsules roughly 0.5 mm in diameter. The capsules, which typically have wall thicknesses from 20 to 60 {mu}m, must possess extraordinary symmetry and concentricity and must have surface finishes of less than 1000 {Angstrom} peak-to-valley variation over surface contours of from 10 to 100`s of {mu}m. This paper reviews the fabrication of these capsules, focusing on the production of the thin-walled polystyrene microshell mandrel around which the capsule is built. The relationship between the capsule characteristics, especially surface finish, and capsule performance is discussed, as are the methods of surface characterization and modification necessary for experiments designed to study the effects of surface roughness on implosion dynamics. Targets for the next generation of ICF facilities using more powerful laser drivers will have to be larger while meeting the same or even more stringent symmetry and surface finish requirements. Some of the technologies for meeting these needs are discussed briefly.

  7. Study of fusion product effects in field-reversed mirrors

    SciTech Connect

    Driemeyer, D.E.

    1980-01-01

    The effect of fusion products (fps) on Field-Reversed Mirror (FRM) reactor concepts has been evaluated through the development of two new computer models. The first code (MCFRM) treats fps as test particles in a fixed background plasma, which is represented as a fluid. MCFRM includes a Monte Carlo treatment of Coulomb scattering and thus provides an accurate treatment of fp behavior even at lower energies where pitch-angle scattering becomes important. The second code (FRMOD) is a steady-state, globally averaged, two-fluid (ion and electron), point model of the FRM plasma that incorporates fp heating and ash buildup values which are consistent with the MCFRM calculations. These codes have been used extensively in the development of an advanced-fuel FRM reactor design (SAFFIRE). A Catalyzed-D version of the plant is also discussed along with an investigation of the steady-state energy distribution of fps in the FRM. User guides for the two computer codes are also included.

  8. First Results from a Charged Fusion Products Diagnostic at MAST

    NASA Astrophysics Data System (ADS)

    Perez, Ramona V.; Allan, Scott Y.; Boeglin, Werner U.; Cecconello, Marco; McClements, Ken G.; Darrow, Douglass S.; MAST Team

    2013-10-01

    We designed, built and installed in MAST a 4-channel solid-state detector array for the detection of the charged deuterium-deuterium fusion products protons and tritons. The array has been mounted at the end of the reciprocating probe arm in MAST allowing it to sample a range of radial positions. First data have been taken in August 2013. The detector signals have been digitized with a 60 MHz sampling rate and have been continuously recorded during plasma discharges. Protons and tritons were readily identified and counted. The observed count rates showed clear dependence on the neutral beam power and were modulated synchronous with saw-teeth. Comparison with data obtained from the MAST neutron camera and the fission chamber neutron detector is planned. We found that time resolutions as low as at least 1 ms were achievable. The detector performance and first analysis results for various plasma scenarios will be presented. Supported in part by DOE grant DE-SC0001157.

  9. 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.

  10. Production of tritium, neutrons, and heat based on the transmission resonance model (TRM) for cold fusion

    NASA Astrophysics Data System (ADS)

    Bush, Robert T.

    1991-05-01

    The TRM has recently been successful in fitting calorimetric data having interesting nonlinear structure. The model appears to provide a natural description for electrolytic cold fusion in terms of ``fractals''. Extended to the time dimension, the model can apparently account for the phenomenon of heat ``bursts''. The TRM combines a transmission condition involving quantized energies and an engergy shift of a Maxwell-Boltzmann energy distribution of deuterons at the cathodic surface that appears related to the concentration overpotential (hydrogen overvoltage). The model suggest three possible regimes vis-a-vis tritium production in terms of this energy shift, and indicates why measurable tritium production in the electrolytic case will tend to be the exception rather than the rule in absence of a recipe: Below a shift of approximately 2.8 meV there is production of both tritium and measureable excess heat, with the possibility of accounting for the Bockris curve indicating about a 1% correlation between excess heat and tritium. However, over the large range from about 2.8 meV to 340 meV energy shift there is a regime of observable excess heat production but little, and probably no measurable, tritium production. The third regime is more hypothetical: It begins at an energy shift of about 1 keV and extends to the boundaries of ``hot'' fusion at about 10 keV. A new type of nucelar reaction, trint (for transmission resonance-induced neutron transfer), is suggested by the model leading to triton and neutron production. A charge distribution ``polarization conjecture'' is the basis for theoretical derivation for the low-energy limit for an energy-dependent branching ratio for D-on-D. When the values of the parameters are inserted, this expression yields an estimate for the ratio of neutron-to-triton production of about 1.64×10-9. The possibility of some three-body reactions is also suggested. A comparison of the TRM's transmission energy levels for palladium deuteride

  11. Fusion hindrance and quasi-fission in heavy-ion induced reactions: disentangling the effect of different parameters

    SciTech Connect

    Fioretto, E.; Stefanini, A. M.; Behera, B. R.; Corradi, L.; Gadea, A.; Latina, A.; Trotta, M.; Beghini, S.; Montagnoli, G.; Scarlassara, F.; Chizhov, A. Yu.; Itkis, I. M.; Itkis, M. G.; Kniajeva, G. N.; Kondratiev, N. A.; Kozulin, E. M.; Pokrovsky, I. V.; Sagaidak, R. N.; Voskressensky, V. M.; Courtin, S.

    2006-04-26

    Experimental results on the fusion inhibition effect near the Coulomb barrier due to the onset of the quasi-fission mechanism are presented. The investigation was focused on reactions induced by 48Ca projectiles on different heavy targets and comparing them to reactions induced by light ions such as 12C and 16O leading to the same compound nuclei. Cross sections and angular distributions of evaporation residues and fission fragments have been measured.

  12. QCD and electroweak interference in Higgs production by gauge boson fusion

    SciTech Connect

    Andersen, Jeppe R.; Smillie, Jennifer M.

    2007-02-01

    We explicitly calculate the contribution to Higgs production at the LHC from the interference between gluon fusion and weak vector boson fusion, and compare it to the pure QCD and pure electroweak result. While the effect is small at tree level, we speculate it will be significantly enhanced by loop effects.

  13. Distribution of Fusion Products and Their Transport Due to Contained Modes

    NASA Astrophysics Data System (ADS)

    Penn, G.; Riconda, C.; Coppi, B.

    1997-11-01

    The influence of the interaction of the fusion products with a class of high-frequency radially localized modes, or ``contained modes'', on the fusion products distribution function is considered and compared with slowing down against electrons. In contrast to low-frequency modes, the interaction with the contained mode does not conserve the magnetic moment of the particles. A quasi-stationary distribution function for the fusion products, neglecting plasma fluctuations and the slowing down of alpha particles on electrons, is described. This model yields information about the velocity-space anisotropy of the fusion products and first-orbit losses onto the plasma chamber. The contained modes have been proposed(B. Coppi, G. Penn, C. Riconda, MIT RLE Report PTP-96/02 (1996)) as a mechanism for experimentally observed enhanced emission at harmonics of the cyclotron frequency of the fusion products.(JET Team, Phys. of Fluids) B5 (1993) 3^,(G.A. Cottrell, V.P. Bhatnagar et al., Nucl. Fusion) 33 (1993) 1365 The possibility to excite these contained modes by an external source is discussed. We point out that contained modes can be exploited for the direct transfer of energy to the fusing nuclei from those energetic fusion products that have a resonant interaction with the modes.

  14. Dynamical Dipole and Equation of State in N/Z Asymmetric Fusion Reactions

    NASA Astrophysics Data System (ADS)

    Giaz, Agnese; Corsi, Anna; Camera, Franco; Wieland, Oliver; Kravchuk, Vladimir L.; Barlini, Sandro; Alba, Rosa; Bednarczyk, P.; Bracco, Angela; Baiocco, Giorgio; Bardelli, Luigi; Benzoni, Giovanna; Bini, M.; Blasi, Nives; Brambilla, Sergio; Bruno, Mauro; Casini, Giovanni; Ciemala, Michal; Cinausero, Marco; Chiari, M.; Colonna, Maria; Crespi, Fabio Celso Luigi; D'Agostino, Michela; Degerlier, Meltem; Di Toro, Massimo; Gramegna, Fabiana; Kmiecik, Maria; Leoni, Silvia; Maiolino, C.; Maj, Adam; Marchi, Tommaso; Mazurek, K.; Meczynski, W.; Million, Benedicte; Montanari, Daniele; Morelli, Luca; Nannini, Adriana; Nicolini, Roberto; Pasquali, G.; Piantelli, S.; Ordine, A.; Poggi, Giacomo; Rizzi, V.; Rizzo, Carmelo; Santonocito, Domenico; Vandone, Valeria; Vannini, G.

    2014-03-01

    In heavy ion reactions, in the case of N/Z asymmetry between projectile and target, the process leading to complete fusion is expected to produce pre-equilibrium dipole γ-ray emission. It is generated during the charge equilibration process and it is known as Dynamical Dipole. A new measurement of the dynamical dipole emission was performed by studying 16O + 116Sn at 12 MeV/u. These data, together with those measured at 8.1 MeV/u and 15.6 MeV/u for the same reaction, provide the dependence on the Dynamical Dipole total emission yield with beam energy and they can be compared with theoretical expectations. The experimental results show a weak increase of the Dynamical Dipole total yield with beam energies and are in agreement with the prediction of a theoretical model based on the Boltzmann-Nordheim-Vlasov (BNV) approach. The measured trend with beam energy does not confirm the rise and fall behavior previously reported for the same fused compound but with a much higher dipole moment.

  15. A novel thermophilic fusion enzyme for trehalose production.

    PubMed

    de Pascale, D; Di Lernia, I; Sasso, M P; Furia, A; De Rosa, M; Rossi, M

    2002-12-01

    In recent years a number of hyperthermophilic micro-organisms of Sulfolobales have been found to produce trehalose from starch and dextrins. In our laboratory genes encoding the trehalosyl dextrin forming enzyme (TDFE) and the trehalose forming enzyme (TFE) of S. solfataricus MT4 have been cloned and expressed in E. coli (Rb791). Here we report the construction of a new protein obtained by fusion of TFE and TDFE coding sequences which is able to produce trehalose from dextrins at high temperature by sequential enzymatic steps. We demonstrate that the bifunctional fusion enzyme is able to produce trehalose starting from malto-oligosaccharides at 75 degrees C. Furthermore we partially purified the recombinant fusion protein from bacterial cell free extracts and from insoluble fractions in which the fusion protein was also found as aggregate in inclusion bodies. PMID:12486454

  16. Linear induction accelerators for fusion and neutron production

    SciTech Connect

    Barletta, W.A. |

    1993-08-01

    Linear induction accelerators (LIA) with pulsed power drives can produce high energy, intense beams or electrons, protons, or heavy ions with megawatts of average power. The continuing development of highly reliable LIA components permits the use such accelerators as cost-effective beam sources to drive fusion pellets with heavy ions, to produce intense neutron fluxes using proton beams, and to generate with electrons microwave power to drive magnetic fusion reactors and high gradient, rf-linacs.

  17. 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

  18. 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.

  19. 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.

  20. Study of the reactions occurring in the fusion of {sup 12}C and {sup 16}O with heavy nuclei at incident energies below 10 MeV/nucleon

    SciTech Connect

    Cavinato, M.; Fabrici, E.; Gadioli, E.; Gadioli Erba, E.; Vergani, P.; Crippa, M.; Colombo, G.; Redaelli, I.; Ripamonti, M.

    1995-11-01

    The excitation functions for production of many residues in the fusion of {sup 12}C with {sup 181}Ta and {sup 197}Au and of {sup 16}O with {sup 165}Ho and {sup 181}Ta have been measured at incident energies varying from the Coulomb barrier up to about 10 MeV/nucleon. The cross sections for fusion of these ions without fission have been deduced and they show that such a process may only occur for projectile angular momenta smaller than a critical value. The excitation functions for individual reactions provide evidence for the emission of preequilibrium nucleons during the thermalization of the composite nucleus and may be satisfactorily reproduced by a calculation based on the Boltzmann master equation theory.

  1. Measurements of charged fusion product diffusion in TFTR

    SciTech Connect

    Boivin, R.L.

    1991-12-01

    The single particle confinement of charged fusion products, namely the 1 MeV triton and the 3 MeV proton, has been studied using a detector located near the outer midplane of TFTR. The detector, which measure the flux of escaping particles, is composed of a scintillator (ZnS(Ag)) and a system of collimating apertures, which permit pitch angle, energy and time resolution. It is mounted on a movable probe which can be inserted 25 cm into the vacuum vessel. Measurements indicate a level of losses higher than expected from a first-orbit loss mechanism alone. The primary candidate for explaining the observed anomalous losses is the toroidal field (TF) stochastic ripple diffusion, theoretically discovered by Goldston, White and Boozer. This loss mechanism is expected to be localized near the outer midplane where, at least at high current ({approx gt} 1.0 MA) it would locally dominate over first-orbit losses. Calculations made with a mapping particle orbit code (MAPLOS) show a semi-quantitative agreement with the measurements. The predominant uncertainties in the numerical simulations were found to originate from the modeling of the first wall geometry and also from the assumed plasma current and source profiles. Direct measurements of the diffusion rate were performed by shadowing the detector with a second movable probe used as an obstacle. The diffusion rate was also measured by moving the detector behind the radius of the RF limiters, located on the outer wall. Comparisons of these experimental results with numerical simulations, which include diffusive mechanisms, indicate a quantitative agreement with the TF stochastic ripple diffusion model.

  2. Measurements of charged fusion product diffusion in TFTR

    SciTech Connect

    Boivin, R.L.

    1991-12-01

    The single particle confinement of charged fusion products, namely the 1 MeV triton and the 3 MeV proton, has been studied using a detector located near the outer midplane of TFTR. The detector, which measure the flux of escaping particles, is composed of a scintillator [ZnS(Ag)] and a system of collimating apertures, which permit pitch angle, energy and time resolution. It is mounted on a movable probe which can be inserted 25 cm into the vacuum vessel. Measurements indicate a level of losses higher than expected from a first-orbit loss mechanism alone. The primary candidate for explaining the observed anomalous losses is the toroidal field (TF) stochastic ripple diffusion, theoretically discovered by Goldston, White and Boozer. This loss mechanism is expected to be localized near the outer midplane where, at least at high current ({approx_gt} 1.0 MA) it would locally dominate over first-orbit losses. Calculations made with a mapping particle orbit code (MAPLOS) show a semi-quantitative agreement with the measurements. The predominant uncertainties in the numerical simulations were found to originate from the modeling of the first wall geometry and also from the assumed plasma current and source profiles. Direct measurements of the diffusion rate were performed by shadowing the detector with a second movable probe used as an obstacle. The diffusion rate was also measured by moving the detector behind the radius of the RF limiters, located on the outer wall. Comparisons of these experimental results with numerical simulations, which include diffusive mechanisms, indicate a quantitative agreement with the TF stochastic ripple diffusion model.

  3. Advanced fusion welding processes, solid state joining and a successful marriage. [production of aerospace structures

    NASA Technical Reports Server (NTRS)

    Miller, F. R.

    1972-01-01

    Joining processes for aerospace systems combine fusion welding and solid state joining during production of metal structures. Detailed characteristics of electron beam welding, plasma arc welding, diffusion welding, inertia welding and weldbond processes are discussed.

  4. Petawatt laser pulses for proton-boron high gain fusion with avalanche reactions excluding problems of nuclear radiation

    NASA Astrophysics Data System (ADS)

    Hora, Heinrich; Lalousis, Paraskevas; Giuffrida, Lorenzo; Margarone, Daniele; Korn, Georg; Eliezer, Shalom; Miley, George H.; Moustaizis, Stavros; Mourou, Gérard

    2015-05-01

    An alternative way may be possible for igniting solid density hydrogen-11B (HB11) fuel. The use of >petawatt-ps laser pulses from the non-thermal ignition based on ultrahigh acceleration of plasma blocks by the nonlinear (ponderomotive) force, has to be combined with the measured ultrahigh magnetic fields in the 10 kilotesla range for cylindrical trapping. The evaluation of measured alpha particles from HB11 reactions arrives at the conclusion that apart from the usual binary nuclear reactions, secondary reactions by an avalanche multiplication may cause the high gains, even much higher than from deuterium tritium fusion. This may be leading to a concept of clean economic power generation.

  5. Mitofusin 1 and 2 play distinct roles in mitochondrial fusion reactions via GTPase activity.

    PubMed

    Ishihara, Naotada; Eura, Yuka; Mihara, Katsuyoshi

    2004-12-15

    The mammalian homologues of yeast and Drosophila Fzo, mitofusin (Mfn) 1 and 2, are both essential for mitochondrial fusion and maintenance of mitochondrial morphology. Though the GTPase domain is required for Mfn protein function, the molecular mechanisms of the GTPase-dependent reaction as well as the functional division of the two Mfn proteins are unknown. To examine the function of Mfn proteins, tethering of mitochondrial membranes was measured in vitro by fluorescence microscopy using green fluorescence protein- or red fluorescent protein-tagged and Mfn1-expressing mitochondria, or by immunoprecipitation using mitochondria harboring HA- or FLAG-tagged Mfn proteins. These experiments revealed that Mfn1-harboring mitochondria were efficiently tethered in a GTP-dependent manner, whereas Mfn2-harboring mitochondria were tethered with only low efficiency. Sucrose density gradient centrifugation followed by co-immunoprecipitation revealed that Mfn1 produced oligomerized approximately 250 kDa and approximately 450 kDa complexes in a GTP-dependent manner. The approximately 450 kDa complex contained oligomerized Mfn1 from distinct apposing membranes (docking complex), whereas the approximately 250 kDa complex was composed of Mfn1 present on the same membrane or in the membrane-solubilized state (cis complex). These results were also confirmed using blue-native PAGE. Mfn1 exhibited higher activity for this reaction than Mfn2. Purified recombinant Mfn1 exhibited approximately eightfold higher GTPase activity than Mfn2. These findings indicate that the two Mfn proteins have distinct activities, and suggest that Mfn1 is mainly responsible for GTP-dependent membrane tethering. PMID:15572413

  6. Dissipation strength of the tilting degree of freedom in fusion-fission reactions

    NASA Astrophysics Data System (ADS)

    Nadtochy, P. N.; Vanin, D. V.; Cheredov, A. V.; Fedorov, S. V.; Ryabov, E. G.; Adeev, G. D.

    2016-05-01

    The four-dimensional Langevin model was applied to calculate a wide set of experimental observables for compound nuclei, formed in heavy-ion fusion-fission reactions. A modified one-body mechanism for nuclear dissipation with a reduction coefficient ks of the contribution from a "wall" formula was used for shapes parameters. Different possibilities of deformation-dependent dissipation coefficient for the K coordinate (γK) were investigated. Presented results demonstrate that the influence of the ks and γK parameters on the calculated quantities can be selectively probed. It was found that it is possible to describe experimental data with the deformation-dependent γK coefficient. One of the possibility is to use large values of γK ≃ 0.2 (MeV zs)-1/2 for compact shapes featuring no neck and small values of γK ≃ 0.0077 (MeV zs)-1/2 for elongated shapes.

  7. Effects of nuclear orientation on fusion and fission process for reactions using actinide target nuclei

    SciTech Connect

    Nishio, K.; Ikezoe, H.; Mitsuoka, S.; Nishinaka, I.; Makii, H.; Nagame, Y.; Watanabe, Y.; Ohtsuki, T.; Hirose, K.; Hofmann, S.

    2010-04-30

    Fission fragment mass distributions in the reaction of {sup 30}Si+{sup 238}U were measured at the energies around the Coulomb barrier. At the above-barrier energies, the mass distribution showed Gaussian shape. At the sub-barrier energies, triple-humped distribution was observed, which consists of symmetric fission and asymmetric fission peaked at A{sub L}/A{sub H}approx =90/178. The asymmetric fission should be attributed to quasifission from the results of the measured evaporation residue (ER) cross-sections produced by {sup 30}Si+{sup 238}U. The cross-section for {sup 263}Sg at the above-barrier energy agree with the statistical model calculation which assumes that the measured fission cross-sections are equal to the fusion cross-sections, whereas the one for {sup 264}Sg measured at the sub-barrier energy is smaller than the calculation, indicating the presence for quasifission. We also report the results on the fragment mass distributions for {sup 36,34}S+{sup 238}U and {sup 40}Ar+{sup 238}U.

  8. Tumor growth prediction with reaction-diffusion and hyperelastic biomechanical model by physiological data fusion.

    PubMed

    Wong, Ken C L; Summers, Ronald M; Kebebew, Electron; Yao, Jianhua

    2015-10-01

    The goal of tumor growth prediction is to model the tumor growth process, which can be achieved by physiological modeling and model personalization from clinical measurements. Although image-driven frameworks have been proposed with promising results, several issues such as infinitesimal strain assumptions, complicated personalization procedures, and the lack of functional information, may limit their prediction accuracy. In view of these issues, we propose a framework for pancreatic neuroendocrine tumor growth prediction, which comprises a FEM-based tumor growth model with coupled reaction-diffusion equation and nonlinear biomechanics. Physiological data fusion of structural and functional images is used to improve the subject-specificity of model personalization, and a derivative-free global optimization algorithm is adopted to facilitate the complicated model and accommodate flexible choices of objective functions. With this flexibility, we propose an objective function accounting for both the tumor volume difference and the root-mean-squared error of intracellular volume fractions. Experiments were performed on synthetic and clinical data to verify the parameter estimation capability and the prediction performance. Comparisons of using different biomechanical models and objective functions were also performed. From the experimental results of eight patient data sets, the average recall, precision, Dice coefficient, and relative volume difference between predicted and measured tumor volumes were 84.5 ± 6.9%, 85.8 ± 8.2%, 84.6 ± 1.7%, and 14.2 ± 8.4%, respectively. PMID:25962846

  9. Simulation and Experimental Study on the Efficiency of Traveling Wave Direct Energy Conversion for Application to Aneutronic Fusion Reactions

    NASA Astrophysics Data System (ADS)

    Tarditi, Alfonso; Chap, Andrew; Miley, George; Scott, John

    2013-10-01

    A study based on both Particle-in-cell (PIC) simulation and experiments is being developed to study the physics of the Traveling Wave Direct Energy Converter (TWDEC,) with the perspective of application to aneutronic fusion reaction products and space propulsion. The PIC model is investigating in detail the key TWDEC physics process by simulating the time-dependent transfer of energy from the ion beam to an electric load connected to ring-type electrodes in cylindrical symmetry. An experimental effort is in progress on a TWDEC test article at NASA, Johnson Space Center with the purpose of studying the conditions for improving the efficiency of the direct energy conversion process. Using a scaled-down ion energy source, the experiment is primarily focused on the effect of the (bunched) beam density on the efficiency and on the optimization of the electrode design. The simulation model is guiding the development of the experimental configuration and will provide details of the beam dynamics for direct comparison with experimental diagnostics. Work supported by NASA, Johnson Space Center.

  10. Activation product release from fusion structural materials in helium

    NASA Astrophysics Data System (ADS)

    Maya, I.; Montgomery, F.; Trester, P.; Burnette, R.; Johnson, W.; Schultz, K.

    1985-08-01

    The release and transport of activated materials-of-construction in a fusion reactor during an accident scenario involving overheating and ingress of oxidants is an important area of safety research. This investigation quantified material release characteristics which result from surface oxide spallation and vaporization for the steel alloys PCA and HT-9 in impure helium and air environments.