Photopions from nuclei in the distorted-wave impulse approximation

NASA Astrophysics Data System (ADS)

Girija, V.; Devanathan, V.

1982-11-01

The formalism for photoproduction of pions from nuclei has been developed in the distorted-wave impulse approximation, taking into account the effect of the change in pion momentum in nuclear medium. Detailed calculations have been done for the reaction 16O(γ, π+)16N for photon energies from 170 to 380 MeV, with a view to investigate the effect due to the gradient operator ∇-->π for momentum of the pion and test the sensitivity of the photopion cross sections to the details of the pion-nucleus optical potential. The results clearly establish that the gradient operator increases the cross sections throughout the energy region considered, the increase being small at lower energies. Also with ∇-->π, the cross sections are rendered less sensitive to the optical potential. The calculated differential cross sections agree very well with the recent experimental data of Shoda et al. for γ-ray energy of 200 MeV. However, the cross sections obtained at medium energies are higher when compared to the available experimental data. NUCLEAR REACTIONS π+ photoproduction from 16O; distorted wave impulse approximation; pion-nucleus optical potentials; gradient operator for the pion momentum.

Longitudinal evaluation of patients with oral potentially malignant disorders using optical imaging and spectroscopy

NASA Astrophysics Data System (ADS)

Schwarz, Richard A.; Pierce, Mark C.; Mondrik, Sharon; Gao, Wen; Quinn, Mary K.; Bhattar, Vijayashree; Williams, Michelle D.; Vigneswaran, Nadarajah; Gillenwater, Ann M.; Richards-Kortum, Rebecca

2012-02-01

Dysplastic and cancerous alterations in oral tissue can be detected noninvasively in vivo using optical techniques including autofluorescence imaging, high-resolution imaging, and spectroscopy. Interim results are presented from a longitudinal study in which optical imaging and spectroscopy were used to evaluate the progression of lesions over time in patients at high risk for development of oral cancer. Over 100 patients with oral potentially malignant disorders have been enrolled in the study to date. Areas of concern in the oral cavity are measured using widefield autofluorescence imaging and depth-sensitive optical spectroscopy during successive clinical visits. Autofluorescence intensity patterns and autofluorescence spectra are tracked over time and correlated with clinical observations. Patients whose lesions progress and who undergo surgery are also measured in the operating room immediately prior to surgery using autofluorescence imaging and spectroscopy, with the addition of intraoperative high-resolution imaging to characterize nuclear size, nuclear crowding, and tissue architecture at selected sites. Optical measurements are compared to histopathology results from biopsies and surgical specimens collected from the measured sites. Autofluorescence imaging and spectroscopy measurements are continued during post-surgery followup visits. We examined correlations between clinical impression and optical classification over time with an average followup period of 4 months. The data collected to date suggest that multimodal optical techniques may aid in noninvasive monitoring of the progression of oral premalignant lesions, biopsy site selection, and accurate delineation of lesion extent during surgery.

Integrated optical maze

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

Roos, E.V.; Hendrix, J.L.

1994-06-01

Improvements to Nuclear Weapons Surety through the development of new detonation control techniques incorporating electro-optic technology are reviewed and proposed in this report. The results of the Kansas City Division`s (KCD`s) literature and vendor search, potential system architecture synthesis, and device test results are the basis of this report. This study has revealed several potential reconfigureable optical interconnect architectures that meet Los Alamos National Laboratory`s preliminary performance specifications. Several planer and global architectures have the potential for meeting the Department of Energy`s applications. Preliminary conclusions on the proposed architectures are discussed. The planer approach of monolithic GaAs amplifier switch arraysmore » is the leading candidate because it meets most of the specifications now. LiNbO{sub 3} and LiTaO{sub 3} planer tree switch arrays are the second choice because they meet all the specifications except for laser power transmission. Although not atop choice, acousto-optical free space switch arrays have been considered and meet most of the specifications. Symmetric-Self Electro-Optic Effect Devices (S-SEED) free space switch arrays are being considered and have excellent potential for smart reconfigureable optical interconnects in the future.« less

Nuclear Cross Sections for Space Radiation Applications

NASA Technical Reports Server (NTRS)

Werneth, C. M.; Maung, K. M.; Ford, W. P.; Norbury, J. W.; Vera, M. D.

2015-01-01

The eikonal, partial wave (PW) Lippmann-Schwinger, and three-dimensional Lippmann-Schwinger (LS3D) methods are compared for nuclear reactions that are relevant for space radiation applications. Numerical convergence of the eikonal method is readily achieved when exact formulas of the optical potential are used for light nuclei (A = 16) and the momentum-space optical potential is used for heavier nuclei. The PW solution method is known to be numerically unstable for systems that require a large number of partial waves, and, as a result, the LS3D method is employed. The effect of relativistic kinematics is studied with the PW and LS3D methods and is compared to eikonal results. It is recommended that the LS3D method be used for high energy nucleon-nucleus reactions and nucleus-nucleus reactions at all energies because of its rapid numerical convergence and stability for both non-relativistic and relativistic kinematics.

Correlation of single mode fiber fabrication factors and radiation response

NASA Astrophysics Data System (ADS)

Friebele, E. J.

1992-02-01

Fiber optic transmission systems, because of their extraordinary channel capacity and decreasing cost, are the preferred terrestrial transmission media of the nation's long distance, inter-city telecommunications infrastructure. Since the commercial telephone network forms the foundation for emergency communication in the event of a national crisis or emergency, additional requirements are placed on the fibers and components of this system. The network must remain operational in the face of such threats as loss of commercial power, disruption by natural causes, violation of physical security, and exposure to the effects of nuclear weapons, including electromagnetic pulse (EMP) and ionizing radiation from the delayed gamma component and fallout. The most stressing environment for the fiber consists of fallout subsequent to a nuclear attack since the long lengths of fiber can be potentially exposed to high total doses. The susceptibility of some types of commercially available fiber optic cable to optical darkening (and hence increased signal loss and bit error rate) from exposure to ionizing radiation raises serious questions about the survivability of such systems in the reconstitution phase of a nuclear conflict.

Nuclear power plant prestressed concrete containment vessel structure monitoring during integrated leakage rate test using three kinds of fiber optic sensors

NASA Astrophysics Data System (ADS)

Liao, Kaixing; Li, Jinke; Kong, Xianglong; Sun, Changsen; Zhao, Xuefeng

2017-04-01

After years of operation, the safety of the prestressed concrete containment vessel (PCCV) structure of Nuclear Power Plant (NPP) is an important aspect. In order to detect the strength degradation and the structure deformation, several sensors such as vibrating wire strain gauge, invar wires and pendulums were installed in PCCV. However, the amounts of sensors above are limited due to the cost. Due to the well durability of fiber optic sensors, three kinds of fiber optic sensors were chosen to install on the surface of PCCV to monitor the deformation during Integrated Leakage Rate Test (ILRT). The three kinds of fiber optic sensors which had their own advantages and disadvantages are Fiber Bragg Grating (FBG), white light interferometry (WLI) and Brillouin Optical Time Domain Analysis (BOTDA). According to the measuring data, the three fiber optic sensors worked well during the ILRT. After the ILRT, the monitoring strain was recoverable thus the PCCV was still in the elastic stage. If these three kinds of fiber optic sensors are widely used in the PCCV, the unusual deformations are easier to detect. As a consequence, the three fiber optic sensors have good potential in the structure health monitoring of PCCV.

Calculation and analysis of cross-sections for p+184W reactions up to 200 MeV

NASA Astrophysics Data System (ADS)

Sun, Jian-Ping; Zhang, Zheng-Jun; Han, Yin-Lu

2015-08-01

A set of optimal proton optical potential parameters for p+ 184W reactions are obtained at incident proton energy up to 250 MeV. Based on these parameters, the reaction cross-sections, elastic scattering angular distributions, energy spectra and double differential cross sections of proton-induced reactions on 184W are calculated and analyzed by using theoretical models which integrate the optical model, distorted Born wave approximation theory, intra-nuclear cascade model, exciton model, Hauser-Feshbach theory and evaporation model. The calculated results are compared with existing experimental data and good agreement is achieved. Supported by National Basic Research Program of China, Technology Research of Accelerator Driven Sub-critical System for Nuclear Waste Transmutation (2007CB209903) and Strategic Priority Research Program of Chinese Academy of Sciences, Thorium Molten Salt Reactor Nuclear Energy System (XDA02010100)

Optical Imaging in Breast Cancer Diagnosis: The Next Evolution

PubMed Central

Ruibal, Alvaro

2012-01-01

Breast cancer is one of the most common cancers among the population of the Western world. Diagnostic methods include mammography, ultrasound, and magnetic resonance; meanwhile, nuclear medicine techniques have a secondary role, being useful in regional assessment and therapy followup. Optical imaging is a very promising imaging technique that uses near-infrared light to assess optical properties of tissues and is expected to play an important role in breast cancer detection. Optical breast imaging can be performed by intrinsic breast tissue contrast alone (hemoglobin, water, and lipid content) or with the use of exogenous fluorescent probes that target specific molecules for breast cancer. Major advantages of optical imaging are that it does not use any radioactive components, very high sensitivity, relatively inexpensive, easily accessible, and the potential to be combined in a multimodal approach with other technologies such as mammography, ultrasound, MRI, and positron emission tomography. Moreover, optical imaging agents could, potentially, be used as “theranostics,” combining the process of diagnosis and therapy. PMID:23304141

Nuclear Spin Nanomagnet in an Optically Excited Quantum Dot

NASA Astrophysics Data System (ADS)

Korenev, V. L.

2007-12-01

Linearly polarized light tuned slightly below the optical transition of the negatively charged exciton (trion) in a single quantum dot causes the spontaneous nuclear spin polarization (self-polarization) at a level close to 100%. The effective magnetic field of spin-polarized nuclei shifts the optical transition energy close to resonance with photon energy. The resonantly enhanced Overhauser effect sustains the stability of the nuclear self-polarization even in the absence of spin polarization of the quantum dot electron. As a result the optically selected single quantum dot represents a tiny magnet with the ferromagnetic ordering of nuclear spins—the nuclear spin nanomagnet.

Nuclear spin nanomagnet in an optically excited quantum dot.

PubMed

Korenev, V L

2007-12-21

Linearly polarized light tuned slightly below the optical transition of the negatively charged exciton (trion) in a single quantum dot causes the spontaneous nuclear spin polarization (self-polarization) at a level close to 100%. The effective magnetic field of spin-polarized nuclei shifts the optical transition energy close to resonance with photon energy. The resonantly enhanced Overhauser effect sustains the stability of the nuclear self-polarization even in the absence of spin polarization of the quantum dot electron. As a result the optically selected single quantum dot represents a tiny magnet with the ferromagnetic ordering of nuclear spins-the nuclear spin nanomagnet.

Widths of transverse momentum distributions in intermediate-energy heavy-ion collisions.

PubMed

Khan, F; Townsend, L W

1993-08-01

The need to include dynamical collision momentum transfer contributions, arising from interacting nuclear and Coulomb fields, to estimates of fragment momentum distributions is discussed. Methods based upon an optical potential model are presented. Comparisons with recent experimental data of the Siegen group for variances of transverse momentum distributions for gold nuclei at 980 A MeV fragmenting on silver foil and plastic nuclear track detector targets are made. The agreement between theory and experiment is good.

Nuclear physics uncertainties of the astrophysical γ-process studied through the 64Zn(p,α)61Cu and 64Zn(p,γ)65Ga reactions

NASA Astrophysics Data System (ADS)

Gyürky, Gy.; Fülöp, Zs.; Halász, Z.; Kiss, G. G.; Szücs, T.

2018-01-01

In a recent work, the cross section measurement of the 64Zn(p,α)61Cu reaction was used to prove that the standard α-nucleus optical potentials used in astrophysical network calculation fail to reproduce the experimental data at energies relevant for heavy element nucleosynthesis. In the present paper the analysis of the obtained experimental data are continued by comparing the results with the predictions using different parameters. It is shown that the recently suggested modification of the standard optical potential leads to a better description of the data.

Selective Optical Addressing of Nuclear Spins through Superhyperfine Interaction in Rare-Earth Doped Solids.

PubMed

Car, B; Veissier, L; Louchet-Chauvet, A; Le Gouët, J-L; Chanelière, T

2018-05-11

In Er^{3+}:Y_{2}SiO_{5}, we demonstrate the selective optical addressing of the ^{89}Y^{3+} nuclear spins through their superhyperfine coupling with the Er^{3+} electronic spins possessing large Landé g factors. We experimentally probe the electron-nuclear spin mixing with photon echo techniques and validate our model. The site-selective optical addressing of the Y^{3+} nuclear spins is designed by adjusting the magnetic field strength and orientation. This constitutes an important step towards the realization of long-lived solid-state qubits optically addressed by telecom photons.

Selective Optical Addressing of Nuclear Spins through Superhyperfine Interaction in Rare-Earth Doped Solids

NASA Astrophysics Data System (ADS)

Car, B.; Veissier, L.; Louchet-Chauvet, A.; Le Gouët, J.-L.; Chanelière, T.

2018-05-01

In Er3 +:Y2SiO5 , we demonstrate the selective optical addressing of the Y89 3 + nuclear spins through their superhyperfine coupling with the Er3 + electronic spins possessing large Landé g factors. We experimentally probe the electron-nuclear spin mixing with photon echo techniques and validate our model. The site-selective optical addressing of the Y3 + nuclear spins is designed by adjusting the magnetic field strength and orientation. This constitutes an important step towards the realization of long-lived solid-state qubits optically addressed by telecom photons.

Neutron radiation effects on Fabry-Perot fiber optic sensors

NASA Astrophysics Data System (ADS)

Liu, Hanying; Talnagi, Joseph; Miller, Don W.

2003-07-01

Nuclear Power Plant operators and Generation IV plant designers are considering advanced data transmission and measurement systems to improve system economics and safety, while concurrently addressing the issue of obsolescence of instrumentation and control systems. Fiber optic sensors have advantages over traditional sensors such as immunity to electromagnetic interference or radio frequency interference, higher sensitivity and accuracy, smaller size and less weight, higher bandwidth and multiplexing capability. A Fabry-Perot fiber optic sensor utilizes a unique interferometric mechanism and data processing technique, and has potential applications in nuclear radiation environments. Three sensors with different gamma irradiation history were irradiated in a mixed neutron/gamma irradiation field, in which the total neutron fluence was 2.6×10 16 neutrons/cm 2 and the total gamma dose was 1.09 MGy. All of them experienced a temperature shift of about 34°F but responded linearly to temperature changes. An annealing phenomenon was observed as the environmental temperature increased, which reduced the offset by approximately 63%.

Predicting the optical observables for nucleon scattering on even-even actinides

NASA Astrophysics Data System (ADS)

Martyanov, D. S.; Soukhovitskiĩ, E. Sh.; Capote, R.; Quesada, J. M.; Chiba, S.

2017-09-01

The previously derived Lane consistent dispersive coupled-channel optical model for nucleon scattering on 232Th and 238U nuclei is extended to describe scattering on even-even actinides with Z = 90-98. A soft-rotator-model (SRM) description of the low-lying nuclear structure is used, where the SRM Hamiltonian parameters are adjusted to the observed collective levels of the target nucleus. SRM nuclear wave functions (mixed in K quantum number) have been used to calculate the coupling matrix elements of the generalized optical model. The “effective” deformations that define inter-band couplings are derived from the SRM Hamiltonian parameters. Conservation of nuclear volume is enforced by introducing a dynamic monopolar term to the deformed potential, leading to additional couplings between rotational bands. The fitted static deformation parameters are in very good agreement with those derived by Wang and collaborators using the Weizsäcker-Skyrme global mass model (WS4), allowing use of the latter to predict cross sections for nuclei without experimental data. A good description of the scarce “optical” experimental database is achieved. SRM couplings and volume conservation allow a precise calculation of the compound-nucleus formation cross sections, which is significantly different from that calculated with rigid-rotor potentials coupling the ground-state rotational band. The derived parameters can be used to describe both neutron- and proton-induced reactions. Supported by International Atomic Energy Agency, through the IAEA Research Contract 19263, by the Spanish Ministry of Economy and Competitivity under Contracts FPA2014-53290-C2-2-P and FPA2016-77689-C2-1-R.

Optical model with multiple band couplings using soft rotator structure

NASA Astrophysics Data System (ADS)

Martyanov, Dmitry; Soukhovitskii, Efrem; Capote, Roberto; Quesada, Jose Manuel; Chiba, Satoshi

2017-09-01

A new dispersive coupled-channel optical model (DCCOM) is derived that describes nucleon scattering on 238U and 232Th targets using a soft-rotator-model (SRM) description of the collective levels of the target nucleus. SRM Hamiltonian parameters are adjusted to the observed collective levels of the target nucleus. SRM nuclear wave functions (mixed in K quantum number) have been used to calculate coupling matrix elements of the generalized optical model. Five rotational bands are coupled: the ground-state band, β-, γ-, non-axial- bands, and a negative parity band. Such coupling scheme includes almost all levels below 1.2 MeV of excitation energy of targets. The "effective" deformations that define inter-band couplings are derived from SRM Hamiltonian parameters. Conservation of nuclear volume is enforced by introducing a monopolar deformed potential leading to additional couplings between rotational bands. The present DCCOM describes the total cross section differences between 238U and 232Th targets within experimental uncertainty from 50 keV up to 200 MeV of neutron incident energy. SRM couplings and volume conservation allow a precise calculation of the compound-nucleus (CN) formation cross sections, which is significantly different from the one calculated with rigid-rotor potentials with any number of coupled levels.

Potential Signatures of Semi-volatile Compounds Associated With Nuclear Processing

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

Probasco, Kathleen M.; Birnbaum, Jerome C.; Maughan, A. D.

2002-06-01

Semi-volatile chemicals associated with nuclear processes (e.g., the reprocessing of uranium to produce plutonium for nuclear weapons, or the separation of actinides from processing waste streams), can provide sticky residues or signatures that will attach to piping, ducting, soil, water, or other surface media. Volatile compounds, that are more suitable for electro-optical sensing, have been well studied. However, the semi-volatile compounds have not been well documented or studied. A majority of these semi-volatile chemicals are more robust than typical gaseous or liquid chemicals and can have lifetimes of several weeks, months, or years in the environment. However, large data gapsmore » exist concerning these potential signature compounds and more research is needed to fill these data gaps so that important signature information is not overlooked or discarded. This report investigates key semi-volatile compounds associated with nuclear separations, identifies available chemical and physical properties, and discusses the degradation products that would result from hydrolysis, radiolysis and oxidation reactions on these compounds.« less

Forging the link between nuclear reactions and nuclear structure.

PubMed

Mahzoon, M H; Charity, R J; Dickhoff, W H; Dussan, H; Waldecker, S J

2014-04-25

A comprehensive description of all single-particle properties associated with the nucleus Ca40 is generated by employing a nonlocal dispersive optical potential capable of simultaneously reproducing all relevant data above and below the Fermi energy. The introduction of nonlocality in the absorptive potentials yields equivalent elastic differential cross sections as compared to local versions but changes the absorption profile as a function of angular momentum suggesting important consequences for the analysis of nuclear reactions. Below the Fermi energy, nonlocality is essential to allow for an accurate representation of particle number and the nuclear charge density. Spectral properties implied by (e, e'p) and (p, 2p) reactions are correctly incorporated, including the energy distribution of about 10% high-momentum nucleons, as experimentally determined by data from Jefferson Lab. These high-momentum nucleons provide a substantial contribution to the energy of the ground state, indicating a residual attractive contribution from higher-body interactions for Ca40 of about 0.64  MeV/A.

Ship Effect Measurements With Fiber Optic Neutron Detector

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

King, Kenneth L.; Dean, Rashe A.; Akbar, Shahzad

2010-08-10

The main objectives of this research project was to assemble, operate, test and characterize an innovatively designed scintillating fiber optic neutron radiation detector manufactured by Innovative American Technology with possible application to the Department of Homeland Security screening for potential radiological and nuclear threats at US borders (Kouzes 2004). One goal of this project was to make measurements of the neutron ship effect for several materials. The Virginia State University DOE FaST/NSF summer student-faculty team made measurements with the fiber optic radiation detector at PNNL above ground to characterize the ship effect from cosmic neutrons, and underground to characterize themore » muon contribution.« less

Optical Polarization of Nuclear Spins in Silicon Carbide

NASA Astrophysics Data System (ADS)

Falk, Abram L.; Klimov, Paul V.; Ivády, Viktor; Szász, Krisztián; Christle, David J.; Koehl, William F.; Gali, Ádám; Awschalom, David D.

2015-06-01

We demonstrate optically pumped dynamic nuclear polarization of 29Si nuclear spins that are strongly coupled to paramagnetic color centers in 4 H - and 6 H -SiC. The 9 9 % ±1 % degree of polarization that we observe at room temperature corresponds to an effective nuclear temperature of 5 μ K . By combining ab initio theory with the experimental identification of the color centers' optically excited states, we quantitatively model how the polarization derives from hyperfine-mediated level anticrossings. These results lay a foundation for SiC-based quantum memories, nuclear gyroscopes, and hyperpolarized probes for magnetic resonance imaging.

Cerenkov luminescence imaging of medical isotopes

PubMed Central

Ruggiero, Alessandro; Holland, Jason P.; Lewis, Jason S.; Grimm, Jan

2011-01-01

The development of novel multimodality imaging agents and techniques represents the current frontier of research in the field of medical imaging science. However, the combination of nuclear tomography with optical techniques has yet to be established. Here, we report the use of the inherent optical emissions from the decay of radiopharmaceuticals for Cerenkov luminescence imaging (CLI) of tumors in vivo and correlate the results with those obtained from concordant immuno-PET studies. Methods In vitro phantom studies were used to validate the visible light emission observed from a range of radionuclides including the positron emitters 18F, 64Cu, 89Zr, and 124I; β-emitter 131I; and α-particle emitter 225Ac for potential use in CLI. The novel radiolabeled monoclonal antibody 89Zr-desferrioxamine B-[DFO-J591 for immuno-PET of prostate-specific membrane antigen (PSMA) expression was used to coregister and correlate the CLI signal observed with the immuno-PET images and biodistribution studies. Results Phantom studies confirmed that Cerenkov radiation can be observed from a range of positron-,β-, and α-emitting radionuclides using standard optical imaging devices. The change in light emission intensity versus time was concordant with radionuclide decay and was also found to correlate linearly with both the activity concentration and the measured PET signal (percentage injected dose per gram). In vivo studies conducted in male severe combined immune deficient mice bearing PSMA-positive, subcutaneous LNCaP tumors demonstrated that tumor-specific uptake of 89Zr-DFO-J591 could be visualized by both immuno-PET and CLI. Optical and immuno-PET signal intensities were found to increase over time from 24 to 96 h, and biodistribution studies were found to correlate well with both imaging modalities. Conclusion These studies represent the first, to our knowledge, quantitative assessment of CLI for measuring radiotracer uptake in vivo. Many radionuclides common to both nuclear tomographic imaging and radiotherapy have the potential to be used in CLI. The value of CLI lies in its ability to image radionuclides that do not emit either positrons or γ-rays and are, thus, unsuitable for use with current nuclear imaging modalities. Optical imaging of Cerenkov radiation emission shows excellent promise as a potential new imaging modality for the rapid, high-throughput screening of radiopharmaceuticals PMID:20554722

A scalable quantum computer with ions in an array of microtraps

PubMed

Cirac; Zoller

2000-04-06

Quantum computers require the storage of quantum information in a set of two-level systems (called qubits), the processing of this information using quantum gates and a means of final readout. So far, only a few systems have been identified as potentially viable quantum computer models--accurate quantum control of the coherent evolution is required in order to realize gate operations, while at the same time decoherence must be avoided. Examples include quantum optical systems (such as those utilizing trapped ions or neutral atoms, cavity quantum electrodynamics and nuclear magnetic resonance) and solid state systems (using nuclear spins, quantum dots and Josephson junctions). The most advanced candidates are the quantum optical and nuclear magnetic resonance systems, and we expect that they will allow quantum computing with about ten qubits within the next few years. This is still far from the numbers required for useful applications: for example, the factorization of a 200-digit number requires about 3,500 qubits, rising to 100,000 if error correction is implemented. Scalability of proposed quantum computer architectures to many qubits is thus of central importance. Here we propose a model for an ion trap quantum computer that combines scalability (a feature usually associated with solid state proposals) with the advantages of quantum optical systems (in particular, quantum control and long decoherence times).

Role of the 3He optical model potential ambiguity in the distorted-wave Born approximation description of the 58Ni(3He, d)59Cu reaction at 130 MeV incident energy

NASA Astrophysics Data System (ADS)

Djaloeis, A.; Alderliesten, C.; Bojowald, J.; Mayer-Böricke, C.; Oelert, W.; Turek, P.

1983-04-01

Angular distributions of 58Ni(3He, d)59Cu transitions leading to the (0.0 MeV, 32-), (0.91 MeV, 52-), and (3.04 MeV, 92+) states in 59Cu have been measured at an incident energy of 130 MeV. The experimental data have been used to study mainly the role of the 3He optical model potential ambiguity in the distorted-wave Born approximation description of the reaction. Satisfactory fits to the data are obtained using a deep helion potential in standard local zero-range calculations. For a shallow 3He potential a comparable description can be achieved if the depth of the real part of the deuteron optical potential is reduced considerably, and nonlocality as well as finite-range corrections are taken into account. Under these conditions, the use of a 3He potential constructed according to the Johnson-Soper prescription yields similar results. NUCLEAR REACTIONS 58Ni (3He, d)59Cu, E=130 MeV; measured dσ(θ)dΩ. Enriched target; DWBA analysis; discussed reaction mechanism.

Rapid and prodium iodide-compatible optical clearing method for brain tissue based on sugar/sugar-alcohol

NASA Astrophysics Data System (ADS)

Yu, Tingting; Qi, Yisong; Wang, Jianru; Feng, Wei; Xu, Jianyi; Zhu, Jingtan; Yao, Yingtao; Gong, Hui; Luo, Qingming; Zhu, Dan

2016-08-01

The developed optical clearing methods show great potential for imaging of large-volume tissues, but these methods present some nonnegligible limitations such as complexity of implementation and long incubation times. In this study, we tried to screen out rapid optical clearing agents by means of molecular dynamical simulation and experimental demonstration. According to the optical clearing potential of sugar and sugar-alcohol, we further evaluated the improvement in the optical clearing efficacy of mouse brain samples, imaging depth, fluorescence preservation, and linear deformation. The results showed that drops of sorbitol, sucrose, and fructose could quickly make the mouse brain sample transparent within 1 to 2 min, and induce about threefold enhancement in imaging depth. The former two could evidently enhance the fluorescence intensity of green fluorescent protein (GFP) and prodium iodide (PI) nuclear dye. Fructose could significantly increase the fluorescence intensity of PI, but slightly decrease the fluorescence intensity of GFP. Even though the three agents caused some shrinkage in samples, the contraction in horizontal and longitudinal directions are almost the same.

Prolonged, brain-wide expression of nuclear-localized GCaMP3 for functional circuit mapping

PubMed Central

Kim, Christina K.; Miri, Andrew; Leung, Louis C.; Berndt, Andre; Mourrain, Philippe; Tank, David W.; Burdine, Rebecca D.

2014-01-01

Larval zebrafish offer the potential for large-scale optical imaging of neural activity throughout the central nervous system; however, several barriers challenge their utility. First, ~panneuronal probe expression has to date only been demonstrated at early larval stages up to 7 days post-fertilization (dpf), precluding imaging at later time points when circuits are more mature. Second, nuclear exclusion of genetically-encoded calcium indicators (GECIs) limits the resolution of functional fluorescence signals collected during imaging. Here, we report the creation of transgenic zebrafish strains exhibiting robust, nuclearly targeted expression of GCaMP3 across the brain up to at least 14 dpf utilizing a previously described optimized Gal4-UAS system. We confirmed both nuclear targeting and functionality of the modified probe in vitro and measured its kinetics in response to action potentials (APs). We then demonstrated in vivo functionality of nuclear-localized GCaMP3 in transgenic zebrafish strains by identifying eye position-sensitive fluorescence fluctuations in caudal hindbrain neurons during spontaneous eye movements. Our methodological approach will facilitate studies of larval zebrafish circuitry by both improving resolution of functional Ca2+ signals and by allowing brain-wide expression of improved GECIs, or potentially any probe, further into development. PMID:25505384

Advancing the Theory of Nuclear Reactions with Rare Isotopes: From the Laboratory to the Cosmos

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

Elster, Charlotte

2015-06-01

The mission of the TORUS Topical Collaboration is to develop new methods that will advance nuclear reaction theory for unstable isotopes by using three-body techniques to improve direct-reaction calculations, and, by using a new partial-fusion theory, to integrate descriptions of direct and compound-nucleus reactions. Ohio University concentrates its efforts on the first part of the mission. Since direct measurements are often not feasible, indirect methods, e.g. (d,p) reactions, should be used. Those (d,p) reactions may be viewed as three-body reactions and described with Faddeev techniques. Faddeev equations in momentum space have a long tradition of utilizing separable interactions in ordermore » to arrive at sets of coupled integral equations in one variable. While there exist several separable representations for the nucleon-nucleon interaction, the optical potential between a neutron (proton) and a nucleus is not readily available in separable form. For this reason we first embarked in introducing a separable representation for complex phenomenological optical potentials of Woods-Saxon type.« less

Nuclear spin circular dichroism.

PubMed

Vaara, Juha; Rizzo, Antonio; Kauczor, Joanna; Norman, Patrick; Coriani, Sonia

2014-04-07

Recent years have witnessed a growing interest in magneto-optic spectroscopy techniques that use nuclear magnetization as the source of the magnetic field. Here we present a formulation of magnetic circular dichroism (CD) due to magnetically polarized nuclei, nuclear spin-induced CD (NSCD), in molecules. The NSCD ellipticity and nuclear spin-induced optical rotation (NSOR) angle correspond to the real and imaginary parts, respectively, of (complex) quadratic response functions involving the dynamic second-order interaction of the electron system with the linearly polarized light beam, as well as the static magnetic hyperfine interaction. Using the complex polarization propagator framework, NSCD and NSOR signals are obtained at frequencies in the vicinity of optical excitations. Hartree-Fock and density-functional theory calculations on relatively small model systems, ethene, benzene, and 1,4-benzoquinone, demonstrate the feasibility of the method for obtaining relatively strong nuclear spin-induced ellipticity and optical rotation signals. Comparison of the proton and carbon-13 signals of ethanol reveals that these resonant phenomena facilitate chemical resolution between non-equivalent nuclei in magneto-optic spectra.

Suppression of nuclear spin bath fluctuations in self-assembled quantum dots induced by inhomogeneous strain

PubMed Central

Chekhovich, E.A.; Hopkinson, M.; Skolnick, M.S.; Tartakovskii, A.I.

2015-01-01

Interaction with nuclear spins leads to decoherence and information loss in solid-state electron-spin qubits. One particular, ineradicable source of electron decoherence arises from decoherence of the nuclear spin bath, driven by nuclear–nuclear dipolar interactions. Owing to its many-body nature nuclear decoherence is difficult to predict, especially for an important class of strained nanostructures where nuclear quadrupolar effects have a significant but largely unknown impact. Here, we report direct measurement of nuclear spin bath coherence in individual self-assembled InGaAs/GaAs quantum dots: spin-echo coherence times in the range 1.2–4.5 ms are found. Based on these values, we demonstrate that strain-induced quadrupolar interactions make nuclear spin fluctuations much slower compared with lattice-matched GaAs/AlGaAs structures. Our findings demonstrate that quadrupolar effects can potentially be used to engineer optically active III-V semiconductor spin-qubits with a nearly noise-free nuclear spin bath, previously achievable only in nuclear spin-0 semiconductors, where qubit network interconnection and scaling are challenging. PMID:25704639

Control of coherence among the spins of a single electron and the three nearest neighbor {sup 13}C nuclei of a nitrogen-vacancy center in diamond

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

Shimo-Oka, T.; Miwa, S.; Suzuki, Y.

2015-04-13

Individual nuclear spins in diamond can be optically detected through hyperfine couplings with the electron spin of a single nitrogen-vacancy (NV) center; such nuclear spins have outstandingly long coherence times. Among the hyperfine couplings in the NV center, the nearest neighbor {sup 13}C nuclear spins have the largest coupling strength. Nearest neighbor {sup 13}C nuclear spins have the potential to perform fastest gate operations, providing highest fidelity in quantum computing. Herein, we report on the control of coherences in the NV center where all three nearest neighbor carbons are of the {sup 13}C isotope. Coherence among the three and fourmore » qubits are generated and analyzed at room temperature.« less

Challenges in the quality assurance of elemental and isotopic analyses in the nuclear domain benefitting from high resolution ICP-OES and sector field ICP-MS.

PubMed

Krachler, Michael; Alvarez-Sarandes, Rafael; Van Winckel, Stefaan

Accurate analytical data reinforces fundamentally the meaningfulness of nuclear fuel performance assessments and nuclear waste characterization. Regularly lacking matrix-matched certified reference materials, quality assurance of elemental and isotopic analysis of nuclear materials remains a challenging endeavour. In this context, this review highlights various dedicated experimental approaches envisaged at the European Commission-Joint Research Centre-Institute for Transuranium Elements to overcome this limitation, mainly focussing on the use of high resolution-inductively coupled plasma-optical emission spectrometry (HR-ICP-OES) and sector field-inductively coupled plasma-mass spectrometry (SF-ICP-MS). However, also α- and γ-spectrometry are included here to help characterise extensively the investigated actinide solutions for their actual concentration, potential impurities and isotopic purity.

Fiber optic cables for severe environment

NASA Astrophysics Data System (ADS)

Massarani, M. G.

1982-10-01

The most severe challenges to the fiber optic cable are related to nuclear weapons testing and other military applications. Nuclear experiments are conducted in deep underground holes. Cables connect the experimental device to recording stations positioned at a certain distance from ground zero. Attractive features provided by fiber optic cable technology include large cost advantages in cable purchase price, savings in handling cost due to the lighter weight, immunity to electromagnetic pulses (EMP), and the capability to transmit high data rates. Details of underground nuclear testing are discussed, taking into account the underground nuclear test environment, and questions of fiber optic cable design for the underground experiments. The use of fiber optics for the Ground Launched Cruise Missile Weapons System (GLCM) is also considered. Attention is given to the GLCM environment, and the proposed cable for GLCM application.

Study of 11Li+p elastic scattering using BHF formalism with three body force

NASA Astrophysics Data System (ADS)

Sharma, Manjari; Haider, W.

2018-04-01

In the present work we have analyzed the elastic scattering data of 11Li + p at 62, 68.4 and 75 MeV/nucleon, using the microscopic optical potential calculated within the framework of Brueckner-Hartree-Fock formalism (BHF). The calculation uses Argonne v18 and Urbana v14 inter-nucleon potentials and the Urbana IX (UVIX) model of three body force. The required nucleon-density distributions for 11Li are obtained using the semi-phenomenological model for nuclear density distributions. The optical potential has been obtained by folding the g-matrices as calculated in BHF (with and without three body forces) over the nucleon density distributions. We have used the exact method for calculating both the direct and the exchange parts of the spin-orbit potential. Our results reveal that the spin-orbit potential significantly contributes to 11Li+p elastic scattering at all three incident energies. Further, the calculated spin-orbit potential in BHF is much smaller and more diffused as compared with the phenomenological spin-orbit potential. The analysis reveals that the calculated microscopic optical potentials, with and without three body force using BHF approach with phenomenological form of density distribution, provides satisfactory agreement with the elastic scattering data for 11Li+p.

On the synergy of nuclear data for fusion and model assumptions

NASA Astrophysics Data System (ADS)

Avrigeanu, Vlad; Avrigeanu, Marilena

2017-09-01

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

Enhanced laboratory sensitivity to variation of the fine-structure constant using highly charged ions.

PubMed

Berengut, J C; Dzuba, V A; Flambaum, V V

2010-09-17

We study atomic systems that are in the frequency range of optical atomic clocks and have enhanced sensitivity to potential time variation of the fine-structure constant α. The high sensitivity is due to coherent contributions from three factors: high nuclear charge Z, high ionization degree, and significant differences in the configuration composition of the states involved. Configuration crossing keeps the frequencies in the optical range despite the large ionization energies. We discuss a few promising examples that have the largest α sensitivities seen in atomic systems.

University Physics, Study Guide, Revised Edition

NASA Astrophysics Data System (ADS)

Benson, Harris

1996-01-01

Partial table of contents: Vectors. One-Dimensional Kinematics. Particle Dynamics II. Work and Energy. Linear Momentum. Systems of Particles. Angular Momentum and Statics. Gravitation. Solids and Fluids. Oscillations. Mechanical Waves. Sound. First Law of Thermodynamics. Kinetic Theory. Entropy and the Second Law of Thermodynamics. Electrostatics. The Electric Field. Gauss's Law. Electric Potential. Current and Resistance. The Magnetic Field. Sources of the Magnetic Field. Electromagnetic Induction. Light: Reflection and Refraction. Lenses and Optical Instruments. Wave Optics I. Special Relativity. Early Quantum Theory. Nuclear Physics. Appendices. Answers to Odd-Numbered Exercises and Problems. Index.

Nuclear fragmentation energy and momentum transfer distributions in relativistic heavy-ion collisions

NASA Technical Reports Server (NTRS)

Khandelwal, Govind S.; Khan, Ferdous

1989-01-01

An optical model description of energy and momentum transfer in relativistic heavy-ion collisions, based upon composite particle multiple scattering theory, is presented. Transverse and longitudinal momentum transfers to the projectile are shown to arise from the real and absorptive part of the optical potential, respectively. Comparisons of fragment momentum distribution observables with experiments are made and trends outlined based on our knowledge of the underlying nucleon-nucleon interaction. Corrections to the above calculations are discussed. Finally, use of the model as a tool for estimating collision impact parameters is indicated.

Long-range dynamic polarization potentials for 11Be projectiles on 64Zn

NASA Astrophysics Data System (ADS)

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

2015-07-01

We investigate the effects of the long-range dynamic polarization (LRDP) potential, which consists of the Coulomb dipole excitation (CDE) potential and the long-range nuclear (LRN) potential, for the 11Be projectile on 64Zn. To study these effects, we perform a χ2 analysis of an optical model including the LRDP potential as well as a conventional short-range nuclear (SRN) potential. To take these effects into account, we argue that both the CDE and LRN potentials are essential to explaining the experimental values of PE, which is the ratio of the elastic scattering cross section to the Rutherford cross section. The Coulomb and nuclear parts of the LRDP potential are found to contribute to a strong absorption effect. Strong absorption occurs because the real part of the CDE and LRN potentials lowers the barrier, and the imaginary part of the CDE and LRN potentials removes the flux from the elastic channel in the 11Be+64Zn system. Finally, we extract the total reaction cross section σR including the inelastic, breakup, and fusion cross sections. The contribution of the inelastic scattering by the first excited state at ɛx1 st=0.32 MeV (1 /2-) is found to be relatively large and cannot be ignored. In addition, our results are shown to agree quite well with the experimental breakup reaction cross section by using a fairly large radius parameter.

Optical potentials for nuclear level structures and nucleon interactions data of tin isotopes based on the soft-rotator model

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

Lee, Jeong-Yeon; Hahn, Insik; Kim, Yeongduk

2009-06-15

The soft-rotator model is applied to self-consistent analyses of the nuclear level structures and the nucleon interaction data of the even-even Sn isotopes, {sup 116}Sn, {sup 118}Sn, {sup 120}Sn, and {sup 122}Sn. The model successfully describes low-lying collective levels of these isotopes, which exhibit neither typical rotational nor harmonic vibrational structures. The experimental nucleon interaction data--total neutron cross sections, proton reaction cross sections, and nucleon elastic and inelastic scattering data--are well described up to 200 MeV in a coupled-channels optical model approach. For the calculations, nuclear wave functions for the Sn isotopes are taken from the nonaxial soft-rotator model withmore » the model parameters adjusted to fit the measured low-lying collective level structures. We find that the {beta}{sub 2} and {beta}{sub 3} deformations for incident protons are larger than those for incident neutrons by {approx}15%, which is clear evidence of the deviation from the pure collective model for these isotopes.« less

New materials for high-energy-resolution x-ray optics

DOE PAGES

Yavas, Hasan; Sutter, John P.; Gog, Thomas; ...

2017-06-09

The use of crystals other than silicon for x-ray optics is becoming more common for many challenging experiments such as resonant inelastic x-ray scattering and nuclear resonant scattering. As more—and more specialized—spectrometers become available at many synchrotron radiation facilities, interest in pushing the limits of experimental energy resolution has increased. The potentially large improvements in resolution and efficiency that nonsilicon optics offer are beginning to be realized. Furthermore, this article covers the background and state of the art for nonsilicon crystal optics with a focus on a resolution of 10 meV or better, concentrating on compounds that form trigonal crystals,more » including sapphire, quartz, and lithium niobate, rather than the more conventional cubic materials, including silicon, diamond, and germanium.« less

Room-temperature in situ nuclear spin hyperpolarization from optically pumped nitrogen vacancy centres in diamond

DOE PAGES

King, Jonathan P.; Jeong, Keunhong; Vassiliou, Christophoros C.; ...

2015-12-07

Low detection sensitivity stemming from the weak polarization of nuclear spins is a primary limitation of magnetic resonance spectroscopy and imaging. Methods have been developed to enhance nuclear spin polarization but they typically require high magnetic fields, cryogenic temperatures or sample transfer between magnets. Here we report bulk, room-temperature hyperpolarization of 13C nuclear spins observed via high-field magnetic resonance. The technique harnesses the high optically induced spin polarization of diamond nitrogen vacancy centres at room temperature in combination with dynamic nuclear polarization. We observe bulk nuclear spin polarization of 6%, an enhancement of ~170,000 over thermal equilibrium. The signal ofmore » the hyperpolarized spins was detected in situ with a standard nuclear magnetic resonance probe without the need for sample shuttling or precise crystal orientation. In conclusion, hyperpolarization via optical pumping/dynamic nuclear polarization should function at arbitrary magnetic fields enabling orders of magnitude sensitivity enhancement for nuclear magnetic resonance of solids and liquids under ambient conditions.« less

Optical Absorption Spectra of Nuclear Filters Modified by Deposition of Silver Nano- and Microparticles

NASA Astrophysics Data System (ADS)

Smolyanskii, A. S.; Kozlova, N. V.; Zheltova, A. V.; Aksyutina, A. S.; Shvedov, A. S.; Lakeev, S. G.

2015-07-01

Light scattering and interference patterns are studied in the optical absorption spectra of nuclear filters based on polyethylene terephthalate fi lms modifi ed by dry aerosol deposition of silver nano- and microparticles. Surface plasmon polaritons and localized plasmons formed by the passage of light through porous silver films are found to have an effect on the diffraction and interference modes. The thickness of silver nano- and microparticle coatings on the surface of the nuclear fi lters was determined from the shift in the interference patterns in the optical absorption spectra of the modified nuclear filters relative to the original nuclear filters. A correlation was found between the estimated coating thickness and the average surface roughness of the nuclear filters modified by layers of silver nano- and microparticles.

Optical pumping of electron and nuclear spin in a negatively-charged quantum dot

NASA Astrophysics Data System (ADS)

Bracker, Allan; Gershoni, David; Korenev, Vladimir

2005-03-01

We report optical pumping of electron and nuclear spins in an individual negatively-charged quantum dot. With a bias-controlled heterostructure, we inject one electron into the quantum dot. Intense laser excitation produces negative photoluminescence polarization, which is easily erased by the Hanle effect, demonstrating optical pumping of a long-lived resident electron. The electron spin lifetime is consistent with the influence of nuclear spin fluctuations. Measuring the Overhauser effect in high magnetic fields, we observe a high degree of nuclear spin polarization, which is closely correlated to electron spin pumping.

Microscopic few-body and Gaussian-shaped density distributions for the analysis of the 6He exotic nucleus with different target nuclei

NASA Astrophysics Data System (ADS)

Aygun, M.; Kucuk, Y.; Boztosun, I.; Ibraheem, Awad A.

2010-12-01

The elastic scattering angular distributions of 6He projectile on different medium and heavy mass target nuclei including 12C, 27Al, 58Ni, 64Zn, 65Cu, 197Au, 208Pb and 209Bi have been examined by using the few-body and Gaussian-shaped density distributions at various energies. The microscopic real parts of the complex nuclear optical potential have been obtained by using the double-folding model for each of the density distributions and the phenomenological imaginary potentials have been taken as the Woods-Saxon type. Comparative results of the few-body and Gaussian-shaped density distributions together with the experimental data are presented within the framework of the optical model.

On the use of the generalized SPRT method in the equivalent hard sphere approximation for nuclear data evaluation

NASA Astrophysics Data System (ADS)

Noguere, Gilles; Archier, Pascal; Bouland, Olivier; Capote, Roberto; Jean, Cyrille De Saint; Kopecky, Stefan; Schillebeeckx, Peter; Sirakov, Ivan; Tamagno, Pierre

2017-09-01

A consistent description of the neutron cross sections from thermal energy up to the MeV region is challenging. One of the first steps consists in optimizing the optical model parameters using average resonance parameters, such as the neutron strength functions. They can be derived from a statistical analysis of the resolved resonance parameters, or calculated with the generalized form of the SPRT method by using scattering matrix elements provided by optical model calculations. One of the difficulties is to establish the contributions of the direct and compound nucleus reactions. This problem was solved by using a slightly modified average R-Matrix formula with an equivalent hard sphere radius deduced from the phase shift originating from the potential. The performances of the proposed formalism are illustrated with results obtained for the 238U+n nuclear systems.

Feasibility study for distributed dose monitoring in ionizing radiation environments with standard and custom-made optical fibers

NASA Astrophysics Data System (ADS)

Van Uffelen, Marco; Berghmans, Francis; Brichard, Benoit; Borgermans, Paul; Decréton, Marc C.

2002-09-01

Optical fibers stimulate much interest since many years for their potential use in various nuclear environments, both for radiation tolerant and EMI-free data communication as well as for distributed sensing. Besides monitoring temperature and stress, measuring ionizing doses with optical fibers is particularly essential in applications such as long-term nuclear waste disposal monitoring, and for real-time aging monitoring of power and signal cables installed inside a reactor containment building. Two distinct options exist to perform optical fiber dosimetry. First, find an accurate model for a restricted application field that accounts for all the parameters that influence the radiation response of a standard fiber, or second, develop a dedicated fiber with a response that will solely depend on the deposited energy. Using various models presented in literature, we evaluate both standard commercially available and custom-made optical fibers under gamma radiation, particularly for distributed dosimetry applications with an optical time domain reflectometer (OTDR). We therefore present the radiation induced attenuation at near-infrared telecom wavelengths up to MGy total dose levels, with dose rates ranging from about 1 Gy/h up to 1 kGy/h, whereas temperature was raised step-wise from 25 °C to 85 °C. Our results allow to determine and compare the practical limitations of distributed dose measurements with both fiber types in terms of temperature sensitivity, dose estimation accuracy and spatial resolution.

Optical hyperpolarization of 13C nuclear spins in nanodiamond ensembles

NASA Astrophysics Data System (ADS)

Chen, Q.; Schwarz, I.; Jelezko, F.; Retzker, A.; Plenio, M. B.

2015-11-01

Dynamical nuclear polarization holds the key for orders of magnitude enhancements of nuclear magnetic resonance signals which, in turn, would enable a wide range of novel applications in biomedical sciences. However, current implementations of DNP require cryogenic temperatures and long times for achieving high polarization. Here we propose and analyze in detail protocols that can achieve rapid hyperpolarization of 13C nuclear spins in randomly oriented ensembles of nanodiamonds at room temperature. Our protocols exploit a combination of optical polarization of electron spins in nitrogen-vacancy centers and the transfer of this polarization to 13C nuclei by means of microwave control to overcome the severe challenges that are posed by the random orientation of the nanodiamonds and their nitrogen-vacancy centers. Specifically, these random orientations result in exceedingly large energy variations of the electron spin levels that render the polarization and coherent control of the nitrogen-vacancy center electron spins as well as the control of their coherent interaction with the surrounding 13C nuclear spins highly inefficient. We address these challenges by a combination of an off-resonant microwave double resonance scheme in conjunction with a realization of the integrated solid effect which, together with adiabatic rotations of external magnetic fields or rotations of nanodiamonds, leads to a protocol that achieves high levels of hyperpolarization of the entire nuclear-spin bath in a randomly oriented ensemble of nanodiamonds even at room temperature. This hyperpolarization together with the long nuclear-spin polarization lifetimes in nanodiamonds and the relatively high density of 13C nuclei has the potential to result in a major signal enhancement in 13C nuclear magnetic resonance imaging and suggests functionalized and hyperpolarized nanodiamonds as a unique probe for molecular imaging both in vitro and in vivo.

High-efficiency optical pumping of nuclear polarization in a GaAs quantum well

NASA Astrophysics Data System (ADS)

Mocek, R. W.; Korenev, V. L.; Bayer, M.; Kotur, M.; Dzhioev, R. I.; Tolmachev, D. O.; Cascio, G.; Kavokin, K. V.; Suter, D.

2017-11-01

The dynamic polarization of nuclear spins by photoexcited electrons is studied in a high quality GaAs/AlGaAs quantum well. We find a surprisingly high efficiency of the spin transfer from the electrons to the nuclei as reflected by a maximum nuclear field of 0.9 T in a tilted external magnetic field of 1 T strength only. This high efficiency is due to a low leakage of spin out of the polarized nuclear system, because mechanisms of spin relaxation other than the hyperfine interaction are strongly suppressed, leading to a long nuclear relaxation time of up to 1000 s. A key ingredient to that end is the low impurity concentration inside the heterostructure, while the electrostatic potential from charged impurities in the surrounding barriers becomes screened through illumination by which the spin relaxation time is increased compared to keeping the system in the dark. This finding indicates a strategy for obtaining high nuclear spin polarization as required for long-lasting carrier spin coherence.

Nuclear-spin optical rotation in xenon

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

Savukov, Igor Mykhaylovich

We report that the nuclear-spin optical rotation (NSOR) effect, which has potential applications in correlated nuclear-spin-resonance optical spectroscopy, has previously been explored experimentally and theoretically in liquid Xe. Calculations of the Xe NSOR constant are very challenging because the result is sensitive to correlations, relativistic effects, and the choice of basis, with strong cancellation between contributions from lowest and remaining states. The relativistic configuration-interaction many-body-theory approach, presented here, is promising because this approach has been successful in predicting various properties of noble-gas atoms, such as energies, oscillator strengths (OSs), Verdet constants, and photoionization cross sections. However, correlations become stronger alongmore » the sequence of noble-gas atoms and the theoretical accuracy in Xe is not as high as, for example, in neon and argon. To improve the accuracy of the Xe Verdet and NSOR constants, which are calculated as explicit sums over the excited states, theoretical values for the several lowest levels are replaced with empirical values of energies, OSs, and hyperfine structure constants. We found that the Xe Verdet constant is in excellent agreement with accurate measurements. To take into account liquid effects, empirical data for energy shifts were also used to correct the NSOR constant. In conclusion, the resulting Xe NSOR constant is in a good agreement with experiment, although the liquid-state effect is treated quite approximately.« less

Nuclear-spin optical rotation in xenon

DOE PAGES

Savukov, Igor Mykhaylovich

2015-10-29

We report that the nuclear-spin optical rotation (NSOR) effect, which has potential applications in correlated nuclear-spin-resonance optical spectroscopy, has previously been explored experimentally and theoretically in liquid Xe. Calculations of the Xe NSOR constant are very challenging because the result is sensitive to correlations, relativistic effects, and the choice of basis, with strong cancellation between contributions from lowest and remaining states. The relativistic configuration-interaction many-body-theory approach, presented here, is promising because this approach has been successful in predicting various properties of noble-gas atoms, such as energies, oscillator strengths (OSs), Verdet constants, and photoionization cross sections. However, correlations become stronger alongmore » the sequence of noble-gas atoms and the theoretical accuracy in Xe is not as high as, for example, in neon and argon. To improve the accuracy of the Xe Verdet and NSOR constants, which are calculated as explicit sums over the excited states, theoretical values for the several lowest levels are replaced with empirical values of energies, OSs, and hyperfine structure constants. We found that the Xe Verdet constant is in excellent agreement with accurate measurements. To take into account liquid effects, empirical data for energy shifts were also used to correct the NSOR constant. In conclusion, the resulting Xe NSOR constant is in a good agreement with experiment, although the liquid-state effect is treated quite approximately.« less

Spin temperature concept verified by optical magnetometry of nuclear spins

NASA Astrophysics Data System (ADS)

Vladimirova, M.; Cronenberger, S.; Scalbert, D.; Ryzhov, I. I.; Zapasskii, V. S.; Kozlov, G. G.; Lemaître, A.; Kavokin, K. V.

2018-01-01

We develop a method of nonperturbative optical control over adiabatic remagnetization of the nuclear spin system and apply it to verify the spin temperature concept in GaAs microcavities. The nuclear spin system is shown to exactly follow the predictions of the spin temperature theory, despite the quadrupole interaction that was earlier reported to disrupt nuclear spin thermalization. These findings open a way for the deep cooling of nuclear spins in semiconductor structures, with the prospect of realizing nuclear spin-ordered states for high-fidelity spin-photon interfaces.

Network signatures of nuclear and cytoplasmic density alterations in a model of pre and postmetastatic colorectal cancer

NASA Astrophysics Data System (ADS)

Damania, Dhwanil; Subramanian, Hariharan; Backman, Vadim; Anderson, Eric C.; Wong, Melissa H.; McCarty, Owen J. T.; Phillips, Kevin G.

2014-01-01

Cells contributing to the pathogenesis of cancer possess cytoplasmic and nuclear structural alterations that accompany their aberrant genetic, epigenetic, and molecular perturbations. Although it is known that architectural changes in primary and metastatic tumor cells can be quantified through variations in cellular density at the nanometer and micrometer spatial scales, the interdependent relationships among nuclear and cytoplasmic density as a function of tumorigenic potential has not been thoroughly investigated. We present a combined optical approach utilizing quantitative phase microscopy and partial wave spectroscopic microscopy to perform parallel structural characterizations of cellular architecture. Using the isogenic SW480 and SW620 cell lines as a model of pre and postmetastatic transition in colorectal cancer, we demonstrate that nuclear and cytoplasmic nanoscale disorder, micron-scale dry mass content, mean dry mass density, and shape metrics of the dry mass density histogram are uniquely correlated within and across different cellular compartments for a given cell type. The correlations of these physical parameters can be interpreted as networks whose nodal importance and level of connection independence differ according to disease stage. This work demonstrates how optically derived biophysical parameters are linked within and across different cellular compartments during the architectural orchestration of the metastatic phenotype.

Cavity Born-Oppenheimer Approximation for Correlated Electron-Nuclear-Photon Systems.

PubMed

Flick, Johannes; Appel, Heiko; Ruggenthaler, Michael; Rubio, Angel

2017-04-11

In this work, we illustrate the recently introduced concept of the cavity Born-Oppenheimer approximation [ Flick et al. PNAS 2017 , 10.1073/pnas.1615509114 ] for correlated electron-nuclear-photon problems in detail. We demonstrate how an expansion in terms of conditional electronic and photon-nuclear wave functions accurately describes eigenstates of strongly correlated light-matter systems. For a GaAs quantum ring model in resonance with a photon mode we highlight how the ground-state electronic potential-energy surface changes the usual harmonic potential of the free photon mode to a dressed mode with a double-well structure. This change is accompanied by a splitting of the electronic ground-state density. For a model where the photon mode is in resonance with a vibrational transition, we observe in the excited-state electronic potential-energy surface a splitting from a single minimum to a double minimum. Furthermore, for a time-dependent setup, we show how the dynamics in correlated light-matter systems can be understood in terms of population transfer between potential energy surfaces. This work at the interface of quantum chemistry and quantum optics paves the way for the full ab initio description of matter-photon systems.

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

Ray, L.; Hoffmann, G.W.; Thaler, R.M.

The treatment of the Coulomb interaction in the multiple scattering theories of Kerman-McManus-Thaler and Watson is examined in detail. By neglecting virtual Coulomb excitations, the lowest order Coulomb term in the Watson optical potential is shown to be a convolution of the point Coulomb interaction with the distributed nuclear charge, while the equivalent Kerman-McManus-Thaler Coulomb potential is obtained from an averaged, single-particle Coulombic T matrix. The Kerman-McManus-Thaler Coulomb potential is expressed as the Watson Coulomb term plus additional Coulomb-nuclear and Coulomb-Coulomb cross terms, and the omission of the extra terms in usual Kerman-McManus-Thaler applications leads to negative infinite total reactionmore » cross section predictions and incorrect pure Coulomb scattering limits. Approximations are presented which eliminate these anomalies. Using the two-potential formula, the full projectile-nucleus T matrix is separated into two terms, one resulting from the distributed nuclear charge and the other being a Coulomb distorted nuclear T matrix. It is shown that the error resulting from the omission of the Kerman-McManus-Thaler Coulomb terms is effectively removed when the pure Coulomb T matrix in Kerman-McManus-Thaler is replaced by the analogous quantity in the Watson approach. Using the various approximations, theoretical angular distributions are obtained for 800 MeV p+/sup 208/Pb elastic scattering and compared with experimental data.« less

X-ray free-electron laser oscillator with nuclear-resonant cavity stabilization and quantum-optical applications

DOE PAGES

Adams, Bernhard W.; Kim, Kwang -Je

2016-08-09

Here, x-ray free-electron-laser oscillators with nuclear-resonant cavity stabilization (NRS-XFELO) hold the promise for providing x-rays with unprecedented coherence properties that will enable interesting quantum-optical and metrological applications. Among these are atom optics with x-ray-based optical elements providing high momentum transfer, or a frequency standard far surpassing the best state-of the-art atomic clocks.

Nuclear physics with antiprotons

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

Dover, C.B.

1984-01-01

Transparencies of an invited talk presented at the Nashville meeting of the American Physical Society, October 18-20, 1984, are included. Topics include: (1) Salient features of two-body N anti N interactions (N anti N reversible NN, annihilation mechanisms (quark models), and optical model phenomenology); (2) anti N-nucleus interactions - elastic, inelastic, etc. (new cross section data, optical potentials, signatures of spin-isospin dependence of N anti N force, and (anti p, p) reactions); and (3) anti N-nucleus annihilation processes (features of cascade or fluid dynamics calculations, searches for baryonium and other exotics, meson interferometry, and (anti p, NN) reactions. (WHK)

Optical transitions in highly charged californium ions with high sensitivity to variation of the fine-structure constant.

PubMed

Berengut, J C; Dzuba, V A; Flambaum, V V; Ong, A

2012-08-17

We study electronic transitions in highly charged Cf ions that are within the frequency range of optical lasers and have very high sensitivity to potential variations in the fine-structure constant, α. The transitions are in the optical range despite the large ionization energies because they lie on the level crossing of the 5f and 6p valence orbitals in the thallium isoelectronic sequence. Cf(16+) is a particularly rich ion, having several narrow lines with properties that minimize certain systematic effects. Cf(16+) has very large nuclear charge and large ionization energy, resulting in the largest α sensitivity seen in atomic systems. The lines include positive and negative shifters.

Instrumentation and data acquisition for satellite testing in nuclear environments

NASA Astrophysics Data System (ADS)

Samyal, B.; Naumann, W.

1982-06-01

Electro-optic and magnetic-optic sensors for measurement of SGEMP-induced electromagnetic fields in and around a satellite in a UGT environment and a fiber optic data link suitable for relaying analog measurements inside the satellite to outside data collection devices are described. The electro-optic and magneto-optic sensors are based on the Pockels and Faraday Effects, respectively. The former has a sensitivity range of 10 to the second power - 10 to the 6th power v/m and the latter 1 x 10 to the minus 6th power - 34 x 10 to the minus 4th power Weber/meters square. Brief theoretical reviews and optical systems for the application of these sensors are presented. These sensors have several advantages over the conventional electrical sensors and they exhibit a great potential for measurement of electromagenetic fields. However, the effects of radiation on these sensors are uncertain and need to be assessed for any future development of these sensors. The fiber optic data link consists of several transmitter modules, located at the satellite, connected by optical fibers to the corresponding receiver modules located at a radiation safe alcove.

Influence of Chloride Ions as Contaminants on the Corrosion Behavior of Alloy 718 in Pool Water of Nuclear Power Plants

NASA Astrophysics Data System (ADS)

Hugues, Jonathan; Andrieu, Eric; Blanc, Christine; Cloué, Jean-Marc

The electrochemical behavior of alloy 718 in a chloride-containing boric acid solution was studied to determine the influence of chloride ions as contaminants of pool water of nuclear power plants on the corrosion behavior of the alloy. Experiments were performed at 20°C and 60°C with chloride concentrations from 1.5 to 15 000 ppm, using stationary measurements i.e. OCP versus time measurements and plotting of current-potential curves. After the electrochemical tests, the samples were observed using optical microscopy. Immersion tests in chloride-containing boric acid solutions were also carried out: samples were immersed for a time as long as 17 weeks at open circuit potential and their residual mechanical properties were measured. Results showed that, whatever the chloride concentration, there was no corrosion for samples immersed at open circuit potential. However, when the samples were polarized at high potentials, intergranular corrosion might be observed in occluded zones.

Inhomogeneous nuclear spin polarization induced by helicity-modulated optical excitation of fluorine-bound electron spins in ZnSe

NASA Astrophysics Data System (ADS)

Heisterkamp, F.; Greilich, A.; Zhukov, E. A.; Kirstein, E.; Kazimierczuk, T.; Korenev, V. L.; Yugova, I. A.; Yakovlev, D. R.; Pawlis, A.; Bayer, M.

2015-12-01

Optically induced nuclear spin polarization in a fluorine-doped ZnSe epilayer is studied by time-resolved Kerr rotation using resonant excitation of donor-bound excitons. Excitation with helicity-modulated laser pulses results in a transverse nuclear spin polarization, which is detected as a change of the Larmor precession frequency of the donor-bound electron spins. The frequency shift in dependence on the transverse magnetic field exhibits a pronounced dispersion-like shape with resonances at the fields of nuclear magnetic resonance of the constituent zinc and selenium isotopes. It is studied as a function of external parameters, particularly of constant and radio frequency external magnetic fields. The width of the resonance and its shape indicate a strong spatial inhomogeneity of the nuclear spin polarization in the vicinity of a fluorine donor. A mechanism of optically induced nuclear spin polarization is suggested based on the concept of resonant nuclear spin cooling driven by the inhomogeneous Knight field of the donor-bound electron.

Cross sections of proton-induced nuclear reactions on bismuth and lead up to 100 MeV

NASA Astrophysics Data System (ADS)

Mokhtari Oranj, L.; Jung, N. S.; Bakhtiari, M.; Lee, A.; Lee, H. S.

2017-04-01

Production cross sections of 209Bi(p , x n )207,206,205,204,203Po, 209Bi(p , pxn) 207,206,205,204,203,202Bi, and natPb(p , x n ) 206,205,204,203,202,201Bi reactions were measured to fill the gap in the excitation functions up to 100 MeV as well as to figure out the effects of different nuclear properties on proton-induced reactions including heavy nuclei. The targets were arranged in two different stacks consisting of Bi, Pb, Al, Au foils and Pb plates. The proton beam intensity was determined by the activation analysis method using 27Al(p ,3 p n )24Na, 197Au(p ,p n )196Au, and 197Au(p , p 3 n )194Au monitor reactions in parallel as well as the Gafchromic film dosimetry method. The activities of produced radionuclei in the foils were measured by the HPGe spectroscopy system. Over 40 new cross sections were measured in the investigated energy range. A satisfactory agreement was observed between the present experimental data and the previously published data. Excitation functions of mentioned reactions were calculated by using the theoretical model based on the latest version of the TALYS code and compared to the new data as well as with other data in the literature. Additionally, the effects of various combinations of the nuclear input parameters of different level density models, optical model potentials, and γ-ray strength functions were considered. It was concluded that if certain level density models are used, the calculated cross sections could be comparable to the measured data. Furthermore, the effects of optical model potential and γ-ray strength functions were considerably lower than that of nuclear level densities.

Hard X-ray mirrors for Nuclear Security

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

Descalle, M. A.; Brejnholt, N.; Hill, R.

Research performed under this LDRD aimed to demonstrate the ability to detect and measure hard X-ray emissions using multilayer X-ray reflective optics above 400 keV, to enable the development of inexpensive and high-accuracy mirror substrates, and to investigate applications of hard X-ray mirrors of interest to the nuclear security community. Experiments conducted at the European Synchrotron Radiation Facility demonstrated hard X-ray mirror reflectivity up to 650 keV for the first time. Hard X-ray optics substrates must have surface roughness under 3 to 4 Angstrom rms, and three materials were evaluated as potential substrates: polycarbonates, thin Schott glass and a newmore » type of flexible glass called Willow Glass®. Chemical smoothing and thermal heating of the surface of polycarbonate samples, which are inexpensive but have poor intrinsic surface characteristics, did not yield acceptable surface roughness. D263 Schott glass was used for the focusing optics of the NASA NuSTAR telescope. The required specialized hardware and process were costly and motivated experiments with a modified non-contact slumping technique. The surface roughness of the glass was preserved and the process yielded cylindrical shells with good net shape pointing to the potential advantage of this technique. Finally, measured surface roughness of 200 and 130 μm thick Willow Glass sheets was between 2 and 2.5 A rms. Additional results of flexibility tests and multilayer deposition campaigns indicated it is a promising substrate for hard X-ray optics. The detection of U and Pu characteristics X-ray lines and gamma emission lines in a high background environment was identified as an area for which X-ray mirrors could have an impact and where focusing optics could help reduce signal to noise ratio by focusing signal onto a smaller detector. Hence the first one twelvetant of a Wolter I focusing optics for the 90 to 140 keV energy range based on aperiodic multilayer coating was designed. Finally, we conducted the first demonstration that reflective multilayer mirrors could be used as diagnostic for HED experiment with an order of magnitude improvement in signal-to-noise ratio for the multilayer optic compared a transmission crystal spectrometer.« less

Multinuclear Detection of Nuclear Spin Optical Rotation at Low Field.

PubMed

Zhu, Yue; Gao, Yuheng; Rodocker, Shane; Savukov, Igor; Hilty, Christian

2018-06-06

We describe the multinuclear detection of nuclear spin optical rotation (NSOR), an effect dependent on the hyperfine interaction between nuclear spins and electrons. Signals of 1 H and 19 F are discriminated by frequency in a single spectrum acquired at sub-millitesla field. The simultaneously acquired optical signal along with the nuclear magnetic resonance signal allows the calculation of the relative magnitude of the NSOR constants corresponding to different nuclei within the sample molecules. This is illustrated by a larger NSOR signal measured at the 19 F frequency despite a smaller corresponding spin concentration. Second, it is shown that heteronuclear J-coupling is observable in the NSOR signal, which can be used to retrieve chemical information. Multinuclear frequency and J resolution can localize optical signals in the molecule. Properties of electronic states at multiple sites in a molecule may therefore ultimately be determined by frequency-resolved NSOR spectroscopy at low field.

Antishadowing and nuclear optics

NASA Astrophysics Data System (ADS)

Białas, A.; CzYżz, W.

1994-05-01

Using standard methods of nuclear optics, we investigate the recent suggestion by Kharzeev and Satz that antishadowing of photons in nuclear matter may be an effect of quantum interference. We show that the Kharzeev-Satz effect is controlled by the real part of the elastic scattering amplitude of the strongly interacting system coupled to the photon and traversing the nucleus. Phenomenological consequences of this observation are discussed.

Developing a clinically viable angle-resolved low coherence interferometry optical biopsy system

NASA Astrophysics Data System (ADS)

Pyhtila, John W.

2007-12-01

Non-invasive optical biopsy techniques, which interrogate tissue in situ, offer a potential method to improve the detection of dysplasia, a pre-cancerous tissue state. Specifically, monitoring of Barrett's esophagus (BE) patients for dysplasia, currently done through systematic biopsy, can be improved by increasing the proportion of at-risk tissue examined. Angle-resolved low coherence interferometry (a/LCI) is an optical spectroscopic technique which measures the depth resolved nuclear morphology of tissue, a key biomarker for identifying dysplasia. Using an animal carcinogenesis model, it was shown that a/LCI can detect dysplasia with great sensitivity and specificity. However, for the clinical application of a/LCI, numerous hurdles must be overcome. This dissertation presents the development of three new a/LCI systems which incrementally address the three main obstacles preventing the clinical application of a/LCI. First, data acquisition time is reduced by implementing a frequency-domain detection scheme using an imaging spectrograph that collects the complete depth resolved angular scattering distribution in parallel. This advance reduces data collection time to a clinically acceptable 40 ms. Second, a fiber probe is developed to enable the endoscopic application of a/LCI. The probe incorporates a single fiber for delivering light and a coherent fiber bundle for collecting the angular distribution of scattered light. Third, a portable device is created through miniaturization of the optical design, and a flexible fiber probe is created using polarization maintaining fiber to deliver the light. These advances allow for the clinical application of the system to ex vivo human tissue samples. The performance of each described system is evaluated through a number of validation studies, including the sizing of polystyrene microspheres, a typical model used in light scattering studies, and the measurement of in vitro cell nuclear diameters, accomplished with sub-wavelength precision and accuracy. The culmination of this work is the first human study using a/LCI in which it is demonstrated that a/LCI depth resolved nuclear morphology measurements provide an excellent means to identify dysplasia in BE patients. The described results demonstrate the great potential for the in vivo application of a/LCI as a targeting mechanism for the detection of dysplasia in Barrett's esophagus patients.

Cell death monitoring using quantitative optical coherence tomography methods

NASA Astrophysics Data System (ADS)

Farhat, Golnaz; Yang, Victor X. D.; Kolios, Michael C.; Czarnota, Gregory J.

2011-03-01

Cell death is characterized by a series of predictable morphological changes, which modify the light scattering properties of cells. We present a multi-parametric approach to detecting changes in subcellular morphology related to cell death using optical coherence tomography (OCT). Optical coherence tomography data were acquired from acute myeloid leukemia (AML) cells undergoing apoptosis over a period of 48 hours. Integrated backscatter (IB) and spectral slope (SS) were computed from OCT backscatter spectra and statistical parameters were extracted from a generalized gamma (GG) distribution fit to OCT signal intensity histograms. The IB increased by 2-fold over 48 hours with significant increases observed as early as 4 hours. The SS increased in steepness by 2.5-fold with significant changes at 12 hours, while the GG parameters were sensitive to apoptotic changes at 24 to 48 hours. Histology slides indicated nuclear condensation and fragmentation at 24 hours, suggesting the late scattering changes could be related to nuclear structure. A second series of measurements from AML cells treated with cisplatin, colchicine or ionizing radiation suggested that the GG parameters could potentially differentiate between modes of cell death. Distinct cellular morphology was observed in histology slides obtained from cells treated under each condition.

Linking Nuclear Reactions and Nuclear Structure on the Way to the Drip Line

NASA Astrophysics Data System (ADS)

Dickhoff, Willem

2012-10-01

The present understanding of the role of short- and long-range physics in determining proton properties near the Fermi energy for stable closed-shell nuclei has relied on data from the (e,e'p) reaction. Hadronic tools to extract such spectroscopic information have been hampered by the lack of a consistent reaction description that provides unambiguous and undisputed results. The dispersive optical model (DOM), originally conceived by Claude Mahaux, provides a unified description of both elastic nucleon scattering and structure information related to single-particle properties below the Fermi energy. The DOM provides the starting point to provide a framework in which nuclear reactions and structure data can be analyzed consistently to provide unambiguous spectroscopic information including its asymmetry dependence. Recent extensions of this approach include the treatment of non-locality to describe experimental data like the nuclear charge density based on information of the spectral density below the Fermi energy, the application of the DOM ingredients to the description of transfer reactions, a comparison of the microscopic content of the nucleon self-energy based on Faddeev-RPA calculations emphasizing long-range correlations with DOM potentials, and a study of the relation between a self-energy which includes the effect of short-range correlations with DOM potentials. The most recent Dom implementation currently in progress abandons the constraint of local potentials completely to allow an accurate description of various properties of the nuclear ground state.

Electron and nuclear spin interactions in the optical spectra of single GaAs quantum dots.

PubMed

Gammon, D; Efros, A L; Kennedy, T A; Rosen, M; Katzer, D S; Park, D; Brown, S W; Korenev, V L; Merkulov, I A

2001-05-28

Fine and hyperfine splittings arising from electron, hole, and nuclear spin interactions in the magneto-optical spectra of individual localized excitons are studied. We explain the magnetic field dependence of the energy splitting through competition between Zeeman, exchange, and hyperfine interactions. An unexpectedly small hyperfine contribution to the splitting close to zero applied field is described well by the interplay between fluctuations of the hyperfine field experienced by the nuclear spin and nuclear dipole/dipole interactions.

Measuring surface-area-to-volume ratios in soft porous materials using laser-polarized xenon interphase exchange nuclear magnetic resonance

NASA Technical Reports Server (NTRS)

Butler, J. P.; Mair, R. W.; Hoffmann, D.; Hrovat, M. I.; Rogers, R. A.; Topulos, G. P.; Walsworth, R. L.; Patz, S.

2002-01-01

We demonstrate a minimally invasive nuclear magnetic resonance (NMR) technique that enables determination of the surface-area-to-volume ratio (S/V) of soft porous materials from measurements of the diffusive exchange of laser-polarized 129Xe between gas in the pore space and 129Xe dissolved in the solid phase. We apply this NMR technique to porous polymer samples and find approximate agreement with destructive stereological measurements of S/V obtained with optical confocal microscopy. Potential applications of laser-polarized xenon interphase exchange NMR include measurements of in vivo lung function in humans and characterization of gas chromatography columns.

Properties of nuclear matter from macroscopic-microscopic mass formulas

NASA Astrophysics Data System (ADS)

Wang, Ning; Liu, Min; Ou, Li; Zhang, Yingxun

2015-12-01

Based on the standard Skyrme energy density functionals together with the extended Thomas-Fermi approach, the properties of symmetric and asymmetric nuclear matter represented in two macroscopic-microscopic mass formulas: Lublin-Strasbourg nuclear drop energy (LSD) formula and Weizsäcker-Skyrme (WS*) formula, are extracted through matching the energy per particle of finite nuclei. For LSD and WS*, the obtained incompressibility coefficients of symmetric nuclear matter are K∞ = 230 ± 11 MeV and 235 ± 11 MeV, respectively. The slope parameter of symmetry energy at saturation density is L = 41.6 ± 7.6 MeV for LSD and 51.5 ± 9.6 MeV for WS*, respectively, which is compatible with the liquid-drop analysis of Lattimer and Lim [4]. The density dependence of the mean-field isoscalar and isovector effective mass, and the neutron-proton effective masses splitting for neutron matter are simultaneously investigated. The results are generally consistent with those from the Skyrme Hartree-Fock-Bogoliubov calculations and nucleon optical potentials, and the standard deviations are large and increase rapidly with density. A better constraint for the effective mass is helpful to reduce uncertainties of the depth of the mean-field potential.

Nuclear magnetic resonance of laser-polarized noble gases in molecules, materials and organisms

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

Goodson, Boyd McLean

1999-12-01

Conventional nuclear magnetic resonance (NMR) spectroscopy and magnetic resonance imaging (MRI) are fundamentally challenged by the insensitivity that stems from the ordinarily low spin polarization achievable in even the strongest NMR magnets. However, by transferring angular momentum from laser light to electronic and nuclear spins, optical pumping methods can increase the nuclear spin polarization of noble gases by several orders of magnitude, thereby greatly enhancing their NMR sensitivity. This dissertation is primarily concerned with the principles and practice of optically pumped nuclear magnetic resonance (OPNMR). The enormous sensitivity enhancement afforded by optical pumping noble gases can be exploited to permitmore » a variety of novel NMR experiments across many disciplines. Many such experiments are reviewed, including the void-space imaging of organisms and materials, NMR and MRI of living tissues, probing structure and dynamics of molecules in solution and on surfaces, and zero-field NMR and MRI.« less

Nuclear magnetic resonance studies of quadrupolar nuclei and dipolar field effects

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

Urban, Jeffry Todd

Experimental and theoretical research conducted in two areas in the field of nuclear magnetic resonance (NMR) spectroscopy is presented: (1) studies of the coherent quantum-mechanical control of the angular momentum dynamics of quadrupolar (spin I > 1/2) nuclei and its application to the determination of molecular structure; and (2) applications of the long-range nuclear dipolar field to novel NMR detection methodologies.The dissertation is organized into six chapters. The first two chapters and associated appendices are intended to be pedagogical and include an introduction to the quantum mechanical theory of pulsed NMR spectroscopy and the time dependent theory of quantum mechanics.more » The third chapter describes investigations of the solid-state multiple-quantum magic angle spinning (MQMAS) NMR experiment applied to I = 5/2 quadrupolar nuclei. This work reports the use of rotary resonance-matched radiofrequency irradiation for sensitivity enhancement of the I = 5/2 MQMAS experiment. These experiments exhibited certain selective line narrowing effects which were investigated theoretically.The fourth chapter extends the discussion of multiple quantum spectroscopy of quadrupolar nuclei to a mostly theoretical study of the feasibility of enhancing the resolution of nitrogen-14 NMR of large biomolecules in solution via double-quantum spectroscopy. The fifth chapter continues to extend the principles of multiple quantum NMR spectroscopy of quadrupolar nuclei to make analogies between experiments in NMR/nuclear quadrupolar resonance (NQR) and experiments in atomic/molecular optics (AMO). These analogies are made through the Hamiltonian and density operator formalism of angular momentum dynamics in the presence of electric and magnetic fields.The sixth chapter investigates the use of the macroscopic nuclear dipolar field to encode the NMR spectrum of an analyte nucleus indirectly in the magnetization of a sensor nucleus. This technique could potentially serve as an encoding module for the recently developed NMR remote detection experiment. The feasibility of using hyperpolarized xenon-129 gas as a sensor is discussed. This work also reports the use of an optical atomic magnetometer to detect the nuclear magnetization of Xe-129 gas, which has potential applicability as a detection module for NMR remote detection experiments.« less

Role of Quantum Vibrations on the Structural, Electronic, and Optical Properties of 9-Methylguanine.

PubMed

Law, Yu Kay; Hassanali, Ali A

2015-11-05

In this work, we report theoretical predictions of the UV-absorption spectra of 9-methylguanine using time dependent density functional theory (TDDFT). Molecular dynamics simulations of the hydrated DNA base are peformed using an empirical force field, Born-Oppenheimer ab initio molecular dynamics (AIMD), and finally path-integral AIMD to understand the role of the underlying electronic potential, solvation, and nuclear quantum vibrations on the absorption spectra. It is shown that the conformational distributions, including hydrogen bonding interactions, are perturbed by the inclusion of nuclear quantum effects, leading to significant changes in the total charge and dipole fluctuations of the DNA base. The calculated absorption spectra using the different sampling protocols shows that the inclusion of nuclear quantum effects causes a significant broadening and red shift of the spectra bringing it into closer agreement with experiments.

Prospects of Optical Single Atom Detection in Noble Gas Solids for Measurements of Rare Nuclear Reactions

NASA Astrophysics Data System (ADS)

Singh, Jaideep; Bailey, Kevin G.; Lu, Zheng-Tian; Mueller, Peter; O'Connor, Thomas P.; Xu, Chen-Yu; Tang, Xiaodong

2013-04-01

Optical detection of single atoms captured in solid noble gas matrices provides an alternative technique to study rare nuclear reactions relevant to nuclear astrophysics. I will describe the prospects of applying this approach for cross section measurements of the ^22Ne,,),25Mg reaction, which is the crucial neutron source for the weak s process inside of massive stars. Noble gas solids are a promising medium for the capture, detection, and manipulation of atoms and nuclear spins. They provide stable and chemically inert confinement for a wide variety of guest species. Because noble gas solids are transparent at optical wavelengths, the guest atoms can be probed using lasers. We have observed that ytterbium in solid neon exhibits intersystem crossing (ISC) which results in a strong green fluorescence (546 nm) under excitation with blue light (389 nm). Several groups have observed ISC in many other guest-host pairs, notably magnesium in krypton. Because of the large wavelength separation of the excitation light and fluorescence light, optical detection of individual embedded guest atoms is feasible. This work is supported by DOE, Office of Nuclear Physics, under contract DE-AC02-06CH11357.

Establishment of Imaging Spectroscopy of Nuclear Gamma-Rays based on Geometrical Optics

PubMed Central

Tanimori, Toru; Mizumura, Yoshitaka; Takada, Atsushi; Miyamoto, Shohei; Takemura, Taito; Kishimoto, Tetsuro; Komura, Shotaro; Kubo, Hidetoshi; Kurosawa, Shunsuke; Matsuoka, Yoshihiro; Miuchi, Kentaro; Mizumoto, Tetsuya; Nakamasu, Yuma; Nakamura, Kiseki; Parker, Joseph D.; Sawano, Tatsuya; Sonoda, Shinya; Tomono, Dai; Yoshikawa, Kei

2017-01-01

Since the discovery of nuclear gamma-rays, its imaging has been limited to pseudo imaging, such as Compton Camera (CC) and coded mask. Pseudo imaging does not keep physical information (intensity, or brightness in Optics) along a ray, and thus is capable of no more than qualitative imaging of bright objects. To attain quantitative imaging, cameras that realize geometrical optics is essential, which would be, for nuclear MeV gammas, only possible via complete reconstruction of the Compton process. Recently we have revealed that “Electron Tracking Compton Camera” (ETCC) provides a well-defined Point Spread Function (PSF). The information of an incoming gamma is kept along a ray with the PSF and that is equivalent to geometrical optics. Here we present an imaging-spectroscopic measurement with the ETCC. Our results highlight the intrinsic difficulty with CCs in performing accurate imaging, and show that the ETCC surmounts this problem. The imaging capability also helps the ETCC suppress the noise level dramatically by ~3 orders of magnitude without a shielding structure. Furthermore, full reconstruction of Compton process with the ETCC provides spectra free of Compton edges. These results mark the first proper imaging of nuclear gammas based on the genuine geometrical optics. PMID:28155870

Establishment of Imaging Spectroscopy of Nuclear Gamma-Rays based on Geometrical Optics.

PubMed

Tanimori, Toru; Mizumura, Yoshitaka; Takada, Atsushi; Miyamoto, Shohei; Takemura, Taito; Kishimoto, Tetsuro; Komura, Shotaro; Kubo, Hidetoshi; Kurosawa, Shunsuke; Matsuoka, Yoshihiro; Miuchi, Kentaro; Mizumoto, Tetsuya; Nakamasu, Yuma; Nakamura, Kiseki; Parker, Joseph D; Sawano, Tatsuya; Sonoda, Shinya; Tomono, Dai; Yoshikawa, Kei

2017-02-03

Since the discovery of nuclear gamma-rays, its imaging has been limited to pseudo imaging, such as Compton Camera (CC) and coded mask. Pseudo imaging does not keep physical information (intensity, or brightness in Optics) along a ray, and thus is capable of no more than qualitative imaging of bright objects. To attain quantitative imaging, cameras that realize geometrical optics is essential, which would be, for nuclear MeV gammas, only possible via complete reconstruction of the Compton process. Recently we have revealed that "Electron Tracking Compton Camera" (ETCC) provides a well-defined Point Spread Function (PSF). The information of an incoming gamma is kept along a ray with the PSF and that is equivalent to geometrical optics. Here we present an imaging-spectroscopic measurement with the ETCC. Our results highlight the intrinsic difficulty with CCs in performing accurate imaging, and show that the ETCC surmounts this problem. The imaging capability also helps the ETCC suppress the noise level dramatically by ~3 orders of magnitude without a shielding structure. Furthermore, full reconstruction of Compton process with the ETCC provides spectra free of Compton edges. These results mark the first proper imaging of nuclear gammas based on the genuine geometrical optics.

206Pb+n resonances for E=600-900 keV: Neutron strength functions

NASA Astrophysics Data System (ADS)

Horen, D. J.; Harvey, J. A.; Hill, N. W.

1981-11-01

Data from high resolution neutron transmission and differential scattering measurements performed on 206Pb have been analyzed for E=600-900 keV. Resonance parameters (i.e., E, l, J, and Γn) have been deduced for many of the 161 resonances observed. Strength functions and potential phase shifts for s-, p-, and d-wave neutrons for En-0-900 keV are compared with optical model calculations. It is found that the phase contributed by the external R function as well as the integrated neutron strength functions can be reproduced for the s and d waves with a well depth of V0=50.4 MeV for the real potential and WD=6.0 MeV for an imaginary surface potential. Somewhat smaller values (V0=48.7 MeV and WD=2.0 MeV) are required to reproduce the p-wave data. These values of the real potential are also found to give the experimentally observed binding energies for the 4s12, 3d32, and 3d52 single particle levels (V0=50.4 MeV), and the 3p12 single particle level (V0=48.7 MeV). Nuclear level densities for s and d waves are found to be well represented by a constant temperature model. However, the model under estimates the number of p-wave resonances. NUCLEAR REACTIONS 206Pb(n), (n,n), E=600-900 keV; measured σT(E), σ(E,θ). 207Pb deduced resonance parameters, Jπ, Γn, neutron strength functions, optical model parameters for l=0,1,2.

Pump-shaped dump optimal control reveals the nuclear reaction pathway of isomerization of a photoexcited cyanine dye.

PubMed

Dietzek, Benjamin; Brüggemann, Ben; Pascher, Torbjörn; Yartsev, Arkady

2007-10-31

Using optimal control as a spectroscopic tool we decipher the details of the molecular dynamics of the essential multidimensional excited-state photoisomerization - a fundamental chemical reaction of key importance in biology. Two distinct nuclear motions are identified in addition to the overall bond-twisting motion: Initially, the reaction is dominated by motion perpendicular to the torsion coordinate. At later times, a second optically active vibration drives the system along the reaction path to the bottom of the excited-state potential. The time scales of the wavepacket motion on a different part of the excited-state potential are detailed by pump-shaped dump optimal control. This technique offers new means to control a chemical reaction far from the Franck-Condon point of absorption and to map details of excited-state reaction pathways revealing unique insights into the underlying reaction mechanism.

Technical Readiness and Gaps Analysis of Commercial Optical Materials and Measurement Systems for Advanced Small Modular Reactors

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

Anheier, Norman C.; Suter, Jonathan D.; Qiao, Hong

2013-08-06

This report intends to support Department of Energy’s Office of Nuclear Energy (DOE-NE) Nuclear Energy Research and Development Roadmap and industry stakeholders by evaluating optical-based instrumentation and control (I&C) concepts for advanced small modular reactor (AdvSMR) applications. These advanced designs will require innovative thinking in terms of engineering approaches, materials integration, and I&C concepts to realize their eventual viability and deployability. The primary goals of this report include: 1. Establish preliminary I&C needs, performance requirements, and possible gaps for AdvSMR designs based on best available published design data. 2. Document commercial off-the-shelf (COTS) optical sensors, components, and materials in termsmore » of their technical readiness to support essential AdvSMR in-vessel I&C systems. 3. Identify technology gaps by comparing the in-vessel monitoring requirements and environmental constraints to COTS optical sensor and materials performance specifications. 4. Outline a future research, development, and demonstration (RD&D) program plan that addresses these gaps and develops optical-based I&C systems that enhance the viability of future AdvSMR designs. The development of clean, affordable, safe, and proliferation-resistant nuclear power is a key goal that is documented in the Nuclear Energy Research and Development Roadmap. This roadmap outlines RD&D activities intended to overcome technical, economic, and other barriers, which currently limit advances in nuclear energy. These activities will ensure that nuclear energy remains a viable component to this nation’s energy security.« less

Investigation and Implementation of Commercially Available Optically Stimulated Luminescence Dosimeters for Use in Fixed Nuclear Accident Dosimeter Systems.

PubMed

Georgeson, David L; Christiansen, Byron H

2018-06-01

Idaho National Laboratory transitioned from an external dosimetry system reliant on thermoluminescent dosimeters to one that uses optically stimulated luminescence dosimeters in 2010. This change not only affected the dosimeters worn by personnel, but those found in the nuclear-accident dosimeters used across Idaho National Laboratory. The elimination of on-site use and processing of thermoluminescent dosimeters impacted Idaho National Laboratory's ability to process nuclear-accident dosimeters in a timely manner. This change in processes drove Idaho National Laboratory to develop an alternative method for fixed nuclear-accident dosimeter gamma-dose analyses. This new method was driven by the need to establish a simple, cost-effective, and rapid-turnaround alternative to the thermoluminescent-dosimeter-based fixed nuclear-accident dosimeter system. An adaptation of existing technologies proved to be the most efficient path to this end. The purpose of this article is to delineate the technical basis for replacing the thermoluminescent dosimeter contained within the Idaho National Laboratory fixed nuclear-accident dosimeter system with optically stimulated luminescence-based Landauer, Inc., nanoDot dosimeters.

The nuclear Thomas-Fermi model

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

Myers, W.D.; Swiatecki, W.J.

1994-08-01

The statistical Thomas-Fermi model is applied to a comprehensive survey of macroscopic nuclear properties. The model uses a Seyler-Blanchard effective nucleon-nucleon interaction, generalized by the addition of one momentum-dependent and one density-dependent term. The adjustable parameters of the interaction were fitted to shell-corrected masses of 1654 nuclei, to the diffuseness of the nuclear surface and to the measured depths of the optical model potential. With these parameters nuclear sizes are well reproduced, and only relatively minor deviations between measured and calculated fission barriers of 36 nuclei are found. The model determines the principal bulk and surface properties of nuclear mattermore » and provides estimates for the more subtle, Droplet Model, properties. The predicted energy vs density relation for neutron matter is in striking correspondence with the 1981 theoretical estimate of Friedman and Pandharipande. Other extreme situations to which the model is applied are a study of Sn isotopes from {sup 82}Sn to {sup 170}Sn, and the rupture into a bubble configuration of a nucleus (constrained to spherical symmetry) which takes place when Z{sup 2}/A exceeds about 100.« less

The Nuclear Thomas-Fermi Model

DOE R&D Accomplishments Database

Myers, W. D.; Swiatecki, W. J.

1994-08-01

The statistical Thomas-Fermi model is applied to a comprehensive survey of macroscopic nuclear properties. The model uses a Seyler-Blanchard effective nucleon-nucleon interaction, generalized by the addition of one momentum-dependent and one density-dependent term. The adjustable parameters of the interaction were fitted to shell-corrected masses of 1654 nuclei, to the diffuseness of the nuclear surface and to the measured depths of the optical model potential. With these parameters nuclear sizes are well reproduced, and only relatively minor deviations between measured and calculated fission barriers of 36 nuclei are found. The model determines the principal bulk and surface properties of nuclear matter and provides estimates for the more subtle, Droplet Model, properties. The predicted energy vs density relation for neutron matter is in striking correspondence with the 1981 theoretical estimate of Friedman and Pandharipande. Other extreme situations to which the model is applied are a study of Sn isotopes from {sup 82}Sn to {sup 170}Sn, and the rupture into a bubble configuration of a nucleus (constrained to spherical symmetry) which takes place when Z{sup 2}/A exceeds about 100.

Elastic Differential Cross Sections

NASA Technical Reports Server (NTRS)

Werneth, Charles M.; Maung, Khin M.; Ford, William P.; Norbury, John W.; Vera, Michael D.

2014-01-01

The eikonal, partial wave (PW) Lippmann-Schwinger, and three-dimensional Lippmann-Schwinger (LS3D) methods are compared for nuclear reactions that are relevant for space radiation applications. Numerical convergence of the eikonal method is readily achieved when exact formulas of the optical potential are used for light nuclei (A less than or equal to 16) and the momentum-space optical potential is used for heavier nuclei. The PW solution method is known to be numerically unstable for systems that require a large number of partial waves, and, as a result, the LS3D method is employed. The effect of relativistic kinematics is studied with the PW and LS3D methods and is compared to eikonal results. It is recommended that the LS3D method be used for high energy nucleon- nucleus reactions and nucleus-nucleus reactions at all energies because of its rapid numerical convergence and stability.

Confinement and Diffusion Effects in Dynamical Nuclear Polarization in Low Dimensional Nanostructures

NASA Astrophysics Data System (ADS)

Henriksen, Dan; Tifrea, Ionel

2012-02-01

We investigate the dynamic nuclear polarization as it results from the hyperfine coupling between nonequilibrium electronic spins and nuclear spins in semiconductor nanostructures. The natural confinement provided by low dimensional nanostructures is responsible for an efficient nuclear spin - electron spin hyperfine coupling [1] and for a reduced value of the nuclear spin diffusion constant [2]. In the case of optical pumping, the induced nuclear spin polarization is position dependent even in the presence of nuclear spin diffusion. This effect should be measurable via optically induced nuclear magnetic resonance or time-resolved Faraday rotation experiments. We discuss the implications of our calculations for the case of GaAs quantum well structures.[4pt] [1] I. Tifrea and M. E. Flatt'e, Phys. Rev. B 84, 155319 (2011).[0pt] [2] A. Malinowski and R. T. Harley, Solid State Commun. 114, 419 (2000).

Nonlocal Nuclear Spin Quieting in Quantum Dot Molecules: Optically Induced Extended Two-Electron Spin Coherence Time.

PubMed

Chow, Colin M; Ross, Aaron M; Kim, Danny; Gammon, Daniel; Bracker, Allan S; Sham, L J; Steel, Duncan G

2016-08-12

We demonstrate the extension of coherence between all four two-electron spin ground states of an InAs quantum dot molecule (QDM) via nonlocal suppression of nuclear spin fluctuations in two vertically stacked quantum dots (QDs), while optically addressing only the top QD transitions. Long coherence times are revealed through dark-state spectroscopy as resulting from nuclear spin locking mediated by the exchange interaction between the QDs. Line shape analysis provides the first measurement of the quieting of the Overhauser field distribution correlating with reduced nuclear spin fluctuations.

Nonlocal Nuclear Spin Quieting in Quantum Dot Molecules: Optically Induced Extended Two-Electron Spin Coherence Time

NASA Astrophysics Data System (ADS)

Chow, Colin M.; Ross, Aaron M.; Kim, Danny; Gammon, Daniel; Bracker, Allan S.; Sham, L. J.; Steel, Duncan G.

2016-08-01

We demonstrate the extension of coherence between all four two-electron spin ground states of an InAs quantum dot molecule (QDM) via nonlocal suppression of nuclear spin fluctuations in two vertically stacked quantum dots (QDs), while optically addressing only the top QD transitions. Long coherence times are revealed through dark-state spectroscopy as resulting from nuclear spin locking mediated by the exchange interaction between the QDs. Line shape analysis provides the first measurement of the quieting of the Overhauser field distribution correlating with reduced nuclear spin fluctuations.

Crystal Growth and Characterization of THO2 and UxTh1-xO2

DTIC Science & Technology

2013-03-01

bulk actinide crystals would open up new possibilities for the detection of weapons of mass destruction, the study of the effect of aging on...way of growing bulk actinide materials of optical quality. These refractory oxide single crystals offer potential applications in thorium nuclear...fuel technology, wide-band-gap uranium-based direct-conversion solid state neutron detectors, and understanding how actinide fuels age with time. ThO2

Optical pumping of the electronic and nuclear spin of single charge-tunable quantum dots.

PubMed

Bracker, A S; Stinaff, E A; Gammon, D; Ware, M E; Tischler, J G; Shabaev, A; Efros, Al L; Park, D; Gershoni, D; Korenev, V L; Merkulov, I A

2005-02-04

We present a comprehensive examination of optical pumping of spins in individual GaAs quantum dots as we change the net charge from positive to neutral to negative with a charge-tunable heterostructure. Negative photoluminescence polarization memory is enhanced by optical pumping of ground state electron spins, which we prove with the first measurements of the Hanle effect on an individual quantum dot. We use the Overhauser effect in a high longitudinal magnetic field to demonstrate efficient optical pumping of nuclear spins for all three charge states of the quantum dot.

Optical Pumping of the Electronic and Nuclear Spin of Single Charge-Tunable Quantum Dots

NASA Astrophysics Data System (ADS)

Bracker, A. S.; Stinaff, E. A.; Gammon, D.; Ware, M. E.; Tischler, J. G.; Shabaev, A.; Efros, Al. L.; Park, D.; Gershoni, D.; Korenev, V. L.; Merkulov, I. A.

2005-02-01

We present a comprehensive examination of optical pumping of spins in individual GaAs quantum dots as we change the net charge from positive to neutral to negative with a charge-tunable heterostructure. Negative photoluminescence polarization memory is enhanced by optical pumping of ground state electron spins, which we prove with the first measurements of the Hanle effect on an individual quantum dot. We use the Overhauser effect in a high longitudinal magnetic field to demonstrate efficient optical pumping of nuclear spins for all three charge states of the quantum dot.

Is the nuclear refractive index lower than cytoplasm? Validation of phase measurements and implications for light scattering technologies.

PubMed

Steelman, Zachary A; Eldridge, Will J; Weintraub, Jacob B; Wax, Adam

2017-12-01

The refractive index (RI) of biological materials is a fundamental parameter for the optical characterization of living systems. Numerous light scattering technologies are grounded in a quantitative knowledge of the refractive index at cellular and subcellular scales. Recent work in quantitative phase microscopy (QPM) has called into question the widely held assumption that the index of the cell nucleus is greater than that of the cytoplasm, a result which disagrees with much of the current literature. In this work, we critically examine the measurement of the nuclear and whole-cell refractive index using QPM, validating that nuclear refractive index is lower than that of cytoplasm in four diverse cell lines and their corresponding isolated nuclei. We further examine Mie scattering and phase-wrapping as potential sources of error in these measurements, finding they have minimal impact. Finally, we use simulation to examine the effects of incorrect RI assumptions on nuclear morphology measurements using angle-resolved scattering information. Despite an erroneous assumption of the nuclear refractive index, accurate measurement of nuclear morphology was maintained, suggesting that light scattering modalities remain effective. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Physics and instrumentation for imaging in-vivo drug distribution.

PubMed

Singh, M; Waluch, V

2000-03-15

Several imaging methods are currently available to measure drugs noninvasively. Of these, two techniques are today central to such measurements: nuclear imaging and magnetic resonance imaging/spectroscopy (MRI and MRS). While other methods, such as optical techniques, are rapidly gaining in interest, they have not yet attained the degree of development that makes them effective in measuring drugs in living systems, except in a small number of examples. The following introduction provides some basic elements of the potential and the limitations of both nuclear imaging and MRI/MRS techniques, methods that will be used in the studies described in the articles in this issue. However, and for those desiring to gain a better understanding of both methods, the reader is advised to consult much more extensive reviews and books describing such methods. A suggested list of books and articles on Nuclear Imaging and MRI/MRS is given.

Electromagnetic and nuclear radiation detector using micromechanical sensors

DOEpatents

Thundat, Thomas G.; Warmack, Robert J.; Wachter, Eric A.

2000-01-01

Electromagnetic and nuclear radiation is detected by micromechanical sensors that can be coated with various interactive materials. As the micromechanical sensors absorb radiation, the sensors bend and/or undergo a shift in resonance characteristics. The bending and resonance changes are detected with high sensitivity by any of several detection methods including optical, capacitive, and piezoresistive methods. Wide bands of the electromagnetic spectrum can be imaged with picoJoule sensitivity, and specific absorptive coatings can be used for selective sensitivity in specific wavelength bands. Microcantilevers coated with optical cross-linking polymers are useful as integrating optical radiation dosimeters. Nuclear radiation dosimetry is possible by fabricating cantilevers from materials that are sensitive to various nuclear particles or radiation. Upon exposure to radiation, the cantilever bends due to stress and its resonance frequency shifts due to changes in elastic properties, based on cantilever shape and properties of the coating.

Development of an advanced antineutrino detector for reactor monitoring

DOE PAGES

Classen, T.; Bernstein, A.; Bowden, N. S.; ...

2014-11-05

We present the development of a compact antineutrino detector for the purpose of nuclear reactor monitoring, improving upon a previously successful design. Our paper will describe the design improvements of the detector which increases the antineutrino detection efficiency threefold over the previous effort. There are two main design improvements over previous generations of detectors for nuclear reactor monitoring: dual-ended optical readout and single volume detection mass. The dual-ended optical readout eliminates the need for fiducialization and increases the uniformity of the detector's optical response. The containment of the detection mass in a single active volume provides more target mass permore » detector footprint, a key design criteria for operating within a nuclear power plant. This technology could allow for real-time monitoring of the evolution of a nuclear reactor core, independent of reactor operator declarations of fuel inventories, and may be of interest to the safeguards community.« less

Synthesis, growth, structural characterization, Hirshfeld analysis and nonlinear optical studies of a methyl substituted chalcone

NASA Astrophysics Data System (ADS)

Prabhu, Shobha R.; Jayarama, A.; Chandrasekharan, K.; Upadhyaya, V.; Ng, Seik Weng

2017-05-01

A new chalcone compound (2E)-3-(3-methylphenyl)-1-(4-nitrophenyl)prop-2-en-1-one (3MPNP) with molecular formula C16H13NO3 has been synthesized and crystallized by slow solvent evaporation technique. The Fourier transform infrared, Fourier transform Raman and nuclear magnetic resonance techniques were used for structural characterization. UV-visible absorption studies were carried out to study the transparency of the crystal in the visible region. Differential scanning calorimetry study shows thermal stability of crystals up to temperature 122 °C. Single crystal X-ray diffraction and powder X-ray diffraction techniques were used to study crystal structure and cell parameters. The Hirshfeld surface and 2-D fingerprint analysis were performed to study the nature of interactions and their quantitative contributions towards the crystal packing. The third order non-linear optical properties have been studied using single beam Z-scan technique and the results show that the material is a potential candidate for optical device applications such as optical limiters and optical switches.

Cerebral blood flow and autoregulation: current measurement techniques and prospects for noninvasive optical methods

PubMed Central

Fantini, Sergio; Sassaroli, Angelo; Tgavalekos, Kristen T.; Kornbluth, Joshua

2016-01-01

Abstract. Cerebral blood flow (CBF) and cerebral autoregulation (CA) are critically important to maintain proper brain perfusion and supply the brain with the necessary oxygen and energy substrates. Adequate brain perfusion is required to support normal brain function, to achieve successful aging, and to navigate acute and chronic medical conditions. We review the general principles of CBF measurements and the current techniques to measure CBF based on direct intravascular measurements, nuclear medicine, X-ray imaging, magnetic resonance imaging, ultrasound techniques, thermal diffusion, and optical methods. We also review techniques for arterial blood pressure measurements as well as theoretical and experimental methods for the assessment of CA, including recent approaches based on optical techniques. The assessment of cerebral perfusion in the clinical practice is also presented. The comprehensive description of principles, methods, and clinical requirements of CBF and CA measurements highlights the potentially important role that noninvasive optical methods can play in the assessment of neurovascular health. In fact, optical techniques have the ability to provide a noninvasive, quantitative, and continuous monitor of CBF and autoregulation. PMID:27403447

New radiological material detection technologies for nuclear forensics: Remote optical imaging and graphene-based sensors.

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

Harrison, Richard Karl; Martin, Jeffrey B.; Wiemann, Dora K.

We developed new detector technologies to identify the presence of radioactive materials for nuclear forensics applications. First, we investigated an optical radiation detection technique based on imaging nitrogen fluorescence excited by ionizing radiation. We demonstrated optical detection in air under indoor and outdoor conditions for alpha particles and gamma radiation at distances up to 75 meters. We also contributed to the development of next generation systems and concepts that could enable remote detection at distances greater than 1 km, and originated a concept that could enable daytime operation of the technique. A second area of research was the development ofmore » room-temperature graphene-based sensors for radiation detection and measurement. In this project, we observed tunable optical and charged particle detection, and developed improved devices. With further development, the advancements described in this report could enable new capabilities for nuclear forensics applications.« less

Wavefront aberrations and retinal image quality in different lenticular opacity types and densities.

PubMed

Wu, Cheng-Zhe; Jin, Hua; Shen, Zhen-Nv; Li, Ying-Jun; Cui, Xun

2017-11-10

To investigate wavefront aberrations in the entire eye and in the internal optics (lens) and retinal image qualities according to different lenticular opacity types and densities. Forty-one eyes with nuclear cataract, 33 eyes with cortical cataract, and 29 eyes with posterior subcapsular cataract were examined. In each group, wavefront aberrations in the entire eye and in the internal optics and retinal image quality were measured using a raytracing aberrometer. Eyes with cortical cataracts showed significantly higher coma-like aberrations compared to the other two groups in both entire eye and internal optic aberrations (P = 0.012 and P = 0.007, respectively). Eyes with nuclear cataract had lower spherical-like aberrations than the other two groups in both entire eye and internal optics aberrations (P < 0.001 and P < 0.001, respectively). In the nuclear cataract group, nuclear lens density was negatively correlated with internal spherical aberrations (r = -0.527, P = 0.005). Wavefront technology is useful for objective and quantitative analysis of retinal image quality deterioration in eyes with different early lenticular opacity types and densities. Understanding the wavefront optical properties of different crystalline lens opacities may help ophthalmic surgeons determine the optimal time to perform cataract surgery.

Precision measurement of the nuclear polarization in laser-cooled, optically pumped 37 K

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

Fenker, B.; Behr, J. A.; Melconian, D.

We report a measurement of the nuclear polarization of laser-cooled, optically pumped 37K atoms which will allow us to precisely measure angular correlation parameters in themore » $${\\beta }^{+}$$-decay of the same atoms. These results will be used to test the V ₋ A framework of the weak interaction at high precision. At the Triumf neutral atom trap (Trinat), a magneto-optical trap confines and cools neutral 37K atoms and optical pumping spin-polarizes them. We monitor the nuclear polarization of the same atoms that are decaying in situ by photoionizing a small fraction of the partially polarized atoms and then use the standard optical Bloch equations to model their population distribution. We obtain an average nuclear polarization of $$\\bar{P}=0.9913\\pm 0.0009$$, which is significantly more precise than previous measurements with this technique. Since our current measurement of the β-asymmetry has $$0.2 \\% $$ statistical uncertainty, the polarization measurement reported here will not limit its overall uncertainty. This result also demonstrates the capability to measure the polarization to $$\\lt 0.1 \\% $$, allowing for a measurement of angular correlation parameters to this level of precision, which would be competitive in searches for new physics.« less

Precision measurement of the nuclear polarization in laser-cooled, optically pumped 37 K

DOE PAGES

Fenker, B.; Behr, J. A.; Melconian, D.; ...

2016-07-13

We report a measurement of the nuclear polarization of laser-cooled, optically pumped 37K atoms which will allow us to precisely measure angular correlation parameters in themore » $${\\beta }^{+}$$-decay of the same atoms. These results will be used to test the V ₋ A framework of the weak interaction at high precision. At the Triumf neutral atom trap (Trinat), a magneto-optical trap confines and cools neutral 37K atoms and optical pumping spin-polarizes them. We monitor the nuclear polarization of the same atoms that are decaying in situ by photoionizing a small fraction of the partially polarized atoms and then use the standard optical Bloch equations to model their population distribution. We obtain an average nuclear polarization of $$\\bar{P}=0.9913\\pm 0.0009$$, which is significantly more precise than previous measurements with this technique. Since our current measurement of the β-asymmetry has $$0.2 \\% $$ statistical uncertainty, the polarization measurement reported here will not limit its overall uncertainty. This result also demonstrates the capability to measure the polarization to $$\\lt 0.1 \\% $$, allowing for a measurement of angular correlation parameters to this level of precision, which would be competitive in searches for new physics.« less

Dynamic nuclear spin polarization in the resonant laser excitation of an InGaAs quantum dot.

PubMed

Högele, A; Kroner, M; Latta, C; Claassen, M; Carusotto, I; Bulutay, C; Imamoglu, A

2012-05-11

Resonant optical excitation of lowest-energy excitonic transitions in self-assembled quantum dots leads to nuclear spin polarization that is qualitatively different from the well-known optical orientation phenomena. By carrying out a comprehensive set of experiments, we demonstrate that nuclear spin polarization manifests itself in quantum dots subjected to finite external magnetic field as locking of the higher energy Zeeman transition to the driving laser field, as well as the avoidance of the resonance condition for the lower energy Zeeman branch. We interpret our findings on the basis of dynamic nuclear spin polarization originating from noncollinear hyperfine interaction and find excellent agreement between experiment and theory. Our results provide evidence for the significance of noncollinear hyperfine processes not only for nuclear spin diffusion and decay, but also for buildup dynamics of nuclear spin polarization in a coupled electron-nuclear spin system.

Measurement of the spin temperature of optically cooled nuclei and GaAs hyperfine constants in GaAs/AlGaAs quantum dots

NASA Astrophysics Data System (ADS)

Chekhovich, E. A.; Ulhaq, A.; Zallo, E.; Ding, F.; Schmidt, O. G.; Skolnick, M. S.

2017-10-01

Deep cooling of electron and nuclear spins is equivalent to achieving polarization degrees close to 100% and is a key requirement in solid-state quantum information technologies. While polarization of individual nuclear spins in diamond and SiC (ref. ) reaches 99% and beyond, it has been limited to 50-65% for the nuclei in quantum dots. Theoretical models have attributed this limit to formation of coherent `dark' nuclear spin states but experimental verification is lacking, especially due to the poor accuracy of polarization degree measurements. Here we measure the nuclear polarization in GaAs/AlGaAs quantum dots with high accuracy using a new approach enabled by manipulation of the nuclear spin states with radiofrequency pulses. Polarizations up to 80% are observed--the highest reported so far for optical cooling in quantum dots. This value is still not limited by nuclear coherence effects. Instead we find that optically cooled nuclei are well described within a classical spin temperature framework. Our findings unlock a route for further progress towards quantum dot electron spin qubits where deep cooling of the mesoscopic nuclear spin ensemble is used to achieve long qubit coherence. Moreover, GaAs hyperfine material constants are measured here experimentally for the first time.

Structural, thermal, optical and nonlinear optical properties of ethylenediaminium picrate single crystals

NASA Astrophysics Data System (ADS)

Indumathi, C.; T. C., Sabari Girisun; Anitha, K.; Alfred Cecil Raj, S.

2017-07-01

A new organic optical limiting material, ethylenediaminium picrate (EDAPA) was synthesized through acid base reaction and grown as single crystals by solvent evaporation method. Single crystal XRD analysis showed that EDAPA crystallizes in orthorhombic system with Cmca as space group. The formation of charge transfer complex during the reaction of ethylenediamine and picric acid was strongly evident through the recorded Fourier Transform Infra Red (FTIR), Raman and Nuclear Magnetic Resonance (NMR) spectrum. Thermal (TG-DTA and DSC) curves indicated that the material possesses high thermal stability with decomposition temperature at 243 °C. Optical (UV-Visible-NIR) analysis showed that the grown crystal was found to be transparent in the entire visible and NIR region. Z-scan studies with intense short pulse (532 nm, 5 ns, 100 μJ) excitations, revealed that EDAPA exhibited two photon absorption behaviour and the nonlinear absorption coefficient was found to be two orders of magnitude higher than some of the known optical limiter like Cu nano glasses. EDAPA exhibited a strong optical limiting action with low limiting threshold which make them a potential candidate for eye and photosensitive component protection against intense short pulse lasers.

Silicon carbide novel optical sensor for combustion systems and nuclear reactors

NASA Astrophysics Data System (ADS)

Lim, Geunsik; Kar, Aravinda

2014-09-01

Crystalline silicon carbide is a wide bandgap semiconductor material with excellent optical properties, chemical inertness, radiation hardness and high mechanical strength at high temperatures. It is an excellent material platform for sensor applications in harsh environments such as combustion systems and nuclear reactors. A laser doping technique is used to fabricate SiC sensors for different combustion gases such as CO2, CO, NO and NO2. The sensor operates based on the principle of semiconductor optics, producing optical signal in contrast to conventional electrical sensors that produces electrical signal. The sensor response is measured with a low power He-Ne or diode laser.

Neutron-antineutron oscillations in nuclei

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

Dover, C.B.; Gal, A.; Richard, J.M.

1983-03-01

We present calculations of the neutron-antineutron (n-n-bar) annihilation lifetime T in deuterium, /sup 16/O, and /sup 56/Fe in terms of the free-space oscillation time tau/sub n/n-bar. The coupled Schroedinger equations for the n and n-bar wave functions in a nucleus are solved numerically, using a realistic shell-model potential which fits the empirical binding energies of the neu- p tron orbits, and a complex n-bar-nucleus optical potential obtained from fits to p-bar-atom level shifts. Most previous estimates of T in nuclei, which exhibit large variations, are found to be quite inaccurate. When the nuclear-physics aspects of the problem are handled properlymore » (in particular, the finite neutron binding, the nuclear radius, and the surface diffuseness), the results are found to be rather stable with respect to allowable changes in the parameters of the nuclear model. We conclude that experimental limits on T in nuclei can be used to give reasonably precise constraints on tau/sub n/n-bar: T>10/sup 30/ or 10/sup 31/ yr leads to tau/sub n/n-bar>(1.5--2) x 10/sup 7/ or (5--6) x 10/sup 7/ sec, respectively.« less

Angle-resolved low-coherence interferometry: an optical biopsy technique for clinical detection of dysplasia in Barrett’s esophagus

PubMed Central

Zhu, Yizheng; Terry, Neil G; Wax, Adam

2012-01-01

Angle-resolved low-coherence interferometry (a/LCI) is an optical biopsy technique that measures scattered light from tissue to determine nuclear size with submicron-level accuracy. The a/LCI probe can be deployed through the accessory channel of a standard endoscope and provides feedback to physicians to guide physical biopsies. The technique has been validated in animal and ex vivo human studies, and has been used to detect dysplasia in Barrett’s esophagus patients in vivo. In a recent clinical study of 46 Barrett’s esophagus patients, a/LCI was able to detect dysplasia with 100% sensitivity and 84% specificity. This report reviews the technique and discusses its potential clinical utility. PMID:22149580

Study of in-medium {\\eta }^{\\prime} properties in the (γ, \\eta ^{\\prime} p) reaction on nuclei

NASA Astrophysics Data System (ADS)

Paryev, E. Ya

2016-01-01

We study the near-threshold photoproduction of {η }\\prime mesons from nuclei in coincidence with forward going protons in the kinematical conditions of the Crystal Barrel/TAPS experiment, recently performed at ELSA. The calculations have been performed within a collision model based on the nuclear spectral function. The model accounts for both the primary γ p\\to η \\prime p process and the two-step intermediate nucleon rescattering processes as well as the effect of the nuclear η \\prime mean-field potential. We calculate the exclusive η \\prime kinetic energy distributions for the 12C(γ, η \\prime p) reaction for different scenarios of η \\prime in-medium modification. We find that the considered two-step rescattering mechanism plays an insignificant role in η \\prime p photoproduction off the carbon target. We also demonstrate that the calculated η \\prime kinetic energy distributions in primary photon-proton η \\prime p production reveal strong sensitivity to the depth of the real η \\prime potential at normal nuclear matter density (or to the η \\prime in-medium mass shift) in the studied incident photon energy regime. Therefore, such observables may be useful to help determine the above η \\prime in-medium renormalization from the comparison of the results of our calculations with the data from the CBELSA/TAPS experiment. In addition, we show that these distributions are also strongly influenced by the momentum-dependent optical potential, which the outgoing participant proton feels inside the carbon nucleus. This potential should be taken into account in the analysis of these data with the aim to obtain information on the η \\prime modification in cold nuclear matter.

Nuclear Technology: Making Informed Decisions.

ERIC Educational Resources Information Center

Altshuler, Kenneth

1989-01-01

Discusses a unit on nuclear technology which is taught in a physics class. Explains the unit design, implementation process, demonstrations used, and topics of discussion that include light and optics, naturally and artificially produced sources of radioactivity, nuclear equations, isotopes and half-lives, and power-generating nuclear reactors.…

Cell Nucleus-Targeting Zwitterionic Carbon Dots.

PubMed

Jung, Yun Kyung; Shin, Eeseul; Kim, Byeong-Su

2015-12-22

An innovative nucleus-targeting zwitterionic carbon dot (CD) vehicle has been developed for anticancer drug delivery and optical monitoring. The zwitterionic functional groups of the CDs introduced by a simple one-step synthesis using β-alanine as a passivating and zwitterionic ligand allow cytoplasmic uptake and subsequent nuclear translocation of the CDs. Moreover, multicolor fluorescence improves the accuracy of the CDs as an optical code. The CD-based drug delivery system constructed by non-covalent grafting of doxorubicin, exhibits superior antitumor efficacy owing to enhanced nuclear delivery in vitro and tumor accumulation in vivo, resulting in highly effective tumor growth inhibition. Since the zwitterionic CDs are highly biocompatible and effectively translocated into the nucleus, it provides a compelling solution to a multifunctional nanoparticle for substantially enhanced nuclear uptake of drugs and optical monitoring of translocation.

Cell Nucleus-Targeting Zwitterionic Carbon Dots

PubMed Central

Jung, Yun Kyung; Shin, Eeseul; Kim, Byeong-Su

2015-01-01

An innovative nucleus-targeting zwitterionic carbon dot (CD) vehicle has been developed for anticancer drug delivery and optical monitoring. The zwitterionic functional groups of the CDs introduced by a simple one-step synthesis using β-alanine as a passivating and zwitterionic ligand allow cytoplasmic uptake and subsequent nuclear translocation of the CDs. Moreover, multicolor fluorescence improves the accuracy of the CDs as an optical code. The CD-based drug delivery system constructed by non-covalent grafting of doxorubicin, exhibits superior antitumor efficacy owing to enhanced nuclear delivery in vitro and tumor accumulation in vivo, resulting in highly effective tumor growth inhibition. Since the zwitterionic CDs are highly biocompatible and effectively translocated into the nucleus, it provides a compelling solution to a multifunctional nanoparticle for substantially enhanced nuclear uptake of drugs and optical monitoring of translocation. PMID:26689549

Estimation of M 1 scissors mode strength for deformed nuclei in the medium- to heavy-mass region by statistical Hauser-Feshbach model calculations

NASA Astrophysics Data System (ADS)

Mumpower, M. R.; Kawano, T.; Ullmann, J. L.; Krtička, M.; Sprouse, T. M.

2017-08-01

Radiative neutron capture is an important nuclear reaction whose accurate description is needed for many applications ranging from nuclear technology to nuclear astrophysics. The description of such a process relies on the Hauser-Feshbach theory which requires the nuclear optical potential, level density, and γ -strength function as model inputs. It has recently been suggested that the M 1 scissors mode may explain discrepancies between theoretical calculations and evaluated data. We explore statistical model calculations with the strength of the M 1 scissors mode estimated to be dependent on the nuclear deformation of the compound system. We show that the form of the M 1 scissors mode improves the theoretical description of evaluated data and the match to experiment in both the fission product and actinide regions. Since the scissors mode occurs in the range of a few keV to a few MeV, it may also impact the neutron capture cross sections of neutron-rich nuclei that participate in the rapid neutron capture process of nucleosynthesis. We comment on the possible impact to nucleosynthesis by evaluating neutron capture rates for neutron-rich nuclei with the M 1 scissors mode active.

Photoluminescence and Optically Stimulated Luminescence Studies of LiAlO2 and LiGaO2 Crystals

DTIC Science & Technology

2015-03-26

tests from the past. In terms of personal dosimetry, OSL dosimeters could potentially replace ther- moluminescence dosimeters (TLDs) which are widely...used by individuals conducting research and maintaining nuclear weapons ( OSL dosimeters are a promising alterna- tive to TLDs because they do not...because they contain lithium, unlike Al2O3:C, the most commonly used OSL dosimeter [2]. The large neutron 1 cross section of lithium-6 makes enriched

Hyperon stars in a modified quark meson coupling model

NASA Astrophysics Data System (ADS)

Mishra, R. N.; Sahoo, H. S.; Panda, P. K.; Barik, N.; Frederico, T.

2016-09-01

We determine the equation of state (EOS) of nuclear matter with the inclusion of hyperons in a self-consistent manner by using a modified quark meson coupling model where the confining interaction for quarks inside a baryon is represented by a phenomenological average potential in an equally mixed scalar-vector harmonic form. The hadron-hadron interaction in nuclear matter is then realized by introducing additional quark couplings to σ ,ω , and ρ mesons through mean-field approximations. The effect of a nonlinear ω -ρ term on the EOS is studied. The hyperon couplings are fixed from the optical potential values and the mass-radius curve is determined satisfying the maximum mass constraint of 2 M⊙ for neutron stars, as determined in recent measurements of the pulsar PSR J0348+0432. We also observe that there is no significant advantage of introducing the nonlinear ω -ρ term in the context of obtaining the star mass constraint in the present set of parametrizations.

Elastic scattering and breakup reactions of the exotic nucleus 8B on nuclear targets

NASA Astrophysics Data System (ADS)

Lukyanov, V. K.; Kadrev, D. N.; Antonov, A. N.; Zemlyanaya, E. V.; Lukyanov, K. V.; Gaidarov, M. K.; Spasova, K.

2018-05-01

Microscopic calculations of the optical potentials (OPs) and elastic scattering cross sections of the proton-rich nucleus 8B on 12C, 58Ni and 208Pb targets are presented. The density distributions of 8B obtained within the variational Monte Carlo (VMC) model and the three-cluster model (3CM) are used to construct the optical potentials (OP). The real part of the hybrid OP (ReOP) is calculated using the folding model with the direct and exchange terms included, while the imaginary part (ImOP) is obtained on the base of the high energy approximation (HEA). In addition, the cluster model, in which 8B consists of a proton halo and a 7Be core is applied to calculate the breakup cross sections of 8B on 9Be, 12C and 197Au targets, as well as the momentum distributions of 7Be fragments. A comparison with the available experimental data is made and a good agreement is obtained.

An apparatus for pulsed ESR and DNP experiments using optically excited triplet states down to liquid helium temperatures

NASA Astrophysics Data System (ADS)

Eichhorn, T. R.; Haag, M.; van den Brandt, B.; Hautle, P.; Wenckebach, W. Th.; Jannin, S.; van der Klink, J. J.; Comment, A.

2013-09-01

In standard Dynamic Nuclear Polarization (DNP) electron spins are polarized at low temperatures in a strong magnetic field and this polarization is transferred to the nuclear spins by means of a microwave field. To obtain high nuclear polarizations cryogenic equipment reaching temperatures of 1 K or below and superconducting magnets delivering several Tesla are required. This equipment strongly limits applications in nuclear and particle physics where beams of particles interact with the polarized nuclei, as well as in neutron scattering science. The problem can be solved using short-lived optically excited triplet states delivering the electron spin. The spin is polarized in the optical excitation process and both the cryogenic equipment and magnet can be simplified significantly. A versatile apparatus is described that allows to perform pulsed dynamic nuclear polarization experiments at X-band using short-lived optically excited triplet sates. The efficient 4He flow cryostat that cools the sample to temperatures between 4 K and 300 K has an optical access with a coupling stage for a fiber transporting the light from a dedicated laser system. It is further designed to be operated on a neutron beam. A combined pulse ESR/DNP spectrometer has been developed to observe and characterize the triplet states and to perform pulse DNP experiments. The ESR probe is based on a dielectric ring resonator of 7 mm inner diameter that can accommodate cubic samples of 5 mm length needed for neutron experiments. NMR measurements can be performed during DNP with a coil integrated in the cavity. With the presented apparatus a proton polarization of 0.5 has been achieved at 0.3 T.

Alterations of the outer retina in non-arteritic anterior ischaemic optic neuropathy detected using spectral-domain optical coherence tomography.

PubMed

Ackermann, Philipp; Brachert, Maike; Albrecht, Philipp; Ringelstein, Marius; Finis, David; Geerling, Gerd; Aktas, Orhan; Guthoff, Rainer

2017-07-01

A characteristic disease pattern may be reflected by retinal layer thickness changes in non-arteritic anterior ischaemic optic neuropathy measured using spectraldomain optical coherence tomography. Retinal layer segmentation is enabled by advanced software. In this study, retinal layer thicknesses in acute and chronic non-arteritic anterior ischaemic optic neuropathy were compared. A single-centre cross-sectional analysis was used. A total of 27 patients (20 age-matched healthy eyes) were included: 14 with acute (<7 days) and 13 patients with chronic non-arteritic anterior ischaemic optic neuropathy. Macular volume and 12° peripapillary ring optical coherence tomography scans were used. The peripapillary thicknesses of the following layers were determined by manual segmentation: retinal nerve fibres, ganglion cells + inner plexiform layer, inner nuclear layer + outer plexiform layer, outer nuclear layer + inner segments of the photoreceptors and outer segments of the photoreceptors to Bruch's membrane. Macular retinal layer thicknesses were automatically determined in volume cubes centred on the fovea. Peripapillary retinal swelling in acute nonarteritic anterior ischaemic optic neuropathy was attributable to retinal nerve fibre layer, ganglion cell layer/inner plexiform layer and outer nuclear layer/segments of the photoreceptors thickening. In chronic cases, peripapillary retinal nerve fibre layer, macular ganglion cell layer and inner plexiform layer thinning were observed. In acute non-arteritic anterior ischaemic optic neuropathy, the inner and outer peripapillary retinal layers are affected by thickness changes. In chronic cases, atrophy of the ganglion cells and their axons and dendrites is evident by inner retinal layer thinning. © 2017 Royal Australian and New Zealand College of Ophthalmologists.

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

NASA Astrophysics Data System (ADS)

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

2018-04-01

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

Optically Induced Nuclear Spin Polarization in the Quantum Hall Regime: The Effect of Electron Spin Polarization through Exciton and Trion Excitations.

PubMed

Akiba, K; Kanasugi, S; Yuge, T; Nagase, K; Hirayama, Y

2015-07-10

We study nuclear spin polarization in the quantum Hall regime through the optically pumped electron spin polarization in the lowest Landau level. The nuclear spin polarization is measured as a nuclear magnetic field B(N) by means of the sensitive resistive detection. We find the dependence of B(N) on the filling factor nonmonotonic. The comprehensive measurements of B(N) with the help of the circularly polarized photoluminescence measurements indicate the participation of the photoexcited complexes, i.e., the exciton and trion (charged exciton), in nuclear spin polarization. On the basis of a novel estimation method of the equilibrium electron spin polarization, we analyze the experimental data and conclude that the filling factor dependence of B(N) is understood by the effect of electron spin polarization through excitons and trions.

Climate changes associated with nuclear war

NASA Technical Reports Server (NTRS)

Toon, O. B.

1986-01-01

Nuclear war, featuring explosion of half the world arsenal of nuclear weapons, would cause urban and forest fires that would inject 20-650 megatons of smoke into the atmosphere. The Northern Hemisphere optical depth would increase to between 0.5-14. All models indicate an increase in optical depths, a large net radiation gain in the smoke layer, and an antigreenhouse effect at the surface. Significant global cooling would proceed, transforming the global climate to a large degree toward that of an airless world. Persisting deficiencies in the models are identified, noting research areas which would improve the accuracies of the predictions.

Neutron-proton effective mass splitting in neutron-rich matter and its impacts on nuclear reactions

NASA Astrophysics Data System (ADS)

Li, Bao-An; Chen, Lie-Wen

2015-04-01

The neutron-proton effective mass splitting in neutron-rich nucleonic matter reflects the spacetime nonlocality of the isovector nuclear interaction. It affects the neutron/proton ratio during the earlier evolution of the Universe, cooling of proto-neutron stars, structure of rare isotopes and dynamics of heavy-ion collisions. While there is still no consensus on whether the neutron-proton effective mass splitting is negative, zero or positive and how it depends on the density as well as the isospin-asymmetry of the medium, significant progress has been made in recent years in addressing these issues. There are different kinds of nucleon effective masses. In this mini-review, we focus on the total effective masses often used in the non-relativistic description of nuclear dynamics. We first recall the connections among the neutron-proton effective mass splitting, the momentum dependence of the isovector potential and the density dependence of the symmetry energy. We then make a few observations about the progress in calculating the neutron-proton effective mass splitting using various nuclear many-body theories and its effects on the isospin-dependence of in-medium nucleon-nucleon cross-sections. Perhaps, our most reliable knowledge so far about the neutron-proton effective mass splitting at saturation density of nuclear matter comes from optical model analyses of huge sets of nucleon-nucleus scattering data accumulated over the last five decades. The momentum dependence of the symmetry potential from these analyses provide a useful boundary condition at saturation density for calibrating nuclear many-body calculations. Several observables in heavy-ion collisions have been identified as sensitive probes of the neutron-proton effective mass splitting in dense neutron-rich matter based on transport model simulations. We review these observables and comment on the latest experimental findings.

Spinning angle optical calibration apparatus

DOEpatents

Beer, Stephen K.; Pratt, II, Harold R.

1991-01-01

An optical calibration apparatus is provided for calibrating and reproducing spinning angles in cross-polarization, nuclear magnetic resonance spectroscopy. An illuminated magnifying apparatus enables optical setting an accurate reproducing of spinning "magic angles" in cross-polarization, nuclear magnetic resonance spectroscopy experiments. A reference mark scribed on an edge of a spinning angle test sample holder is illuminated by a light source and viewed through a magnifying scope. When the "magic angle" of a sample material used as a standard is attained by varying the angular position of the sample holder, the coordinate position of the reference mark relative to a graduation or graduations on a reticle in the magnifying scope is noted. Thereafter, the spinning "magic angle" of a test material having similar nuclear properties to the standard is attained by returning the sample holder back to the originally noted coordinate position.

Explicit inclusion of nonlocality in ( d , p ) transfer reactions

DOE PAGES

Titus, L. J.; Nunes, F. M.; Potel, G.

2016-01-06

Traditionally, nucleon-nucleus optical potentials are made local for convenience. In recent work we studied the effects of including nonlocal interactions explicitly in the final state for (d,p) reactions, within the distorted wave Born approximation. Our goal in this work is to develop an improved formalism for nonlocal interactions that includes deuteron breakup and to use it to study the effects of including nonlocal interactions in transfer (d,p) reactions, in both the deuteron and the proton channel. We extend the finite-range adiabatic distorted wave approximation to include nonlocal nucleon optical potentials. We apply our method to (d,p) reactions on 16O, 40Ca,more » 48Ca, 126Sn, 132Sn, and 208Pb at 10, 20 and 50 MeV. Here, we find that nonlocality in the deuteron scattering state reduces the amplitude of the wave function in the nuclear interior, and shifts the wave function outward. In many cases, this has the effect of increasing the transfer cross section at the first peak of the angular distributions. This increase was most significant for heavy targets and for reactions at high energies. Lastly, our systematic study shows that, if only local optical potentials are used in the analysis of experimental (d, p) transfer cross sections, the extracted spectroscopic factors may be incorrect by up to 40% due to the local approximation.« less

Nuclear spin cooling by electric dipole spin resonance and coherent population trapping

NASA Astrophysics Data System (ADS)

Li, Ai-Xian; Duan, Su-Qing; Zhang, Wei

2017-09-01

Nuclear spin fluctuation suppression is a key issue in preserving electron coherence for quantum information/computation. We propose an efficient way of nuclear spin cooling in semiconductor quantum dots (QDs) by the coherent population trapping (CPT) and the electric dipole spin resonance (EDSR) induced by optical fields and ac electric fields. The EDSR can enhance the spin flip-flop rate and may bring out bistability under certain conditions. By tuning the optical fields, we can avoid the EDSR induced bistability and obtain highly polarized nuclear spin state, which results in long electron coherence time. With the help of CPT and EDSR, an enhancement of 1500 times of the electron coherence time can been obtained after a 500 ns preparation time.

Nuclear-matter radius studies from 58Ni(α ,α ) experiments at the GSI Experimental Storage Ring with the EXL facility

NASA Astrophysics Data System (ADS)

Zamora, J. C.; Aumann, T.; Bagchi, S.; Bönig, S.; Csatlós, M.; Dillmann, I.; Dimopoulou, C.; Egelhof, P.; Eremin, V.; Furuno, T.; Geissel, H.; Gernhäuser, R.; Harakeh, M. N.; Hartig, A.-L.; Ilieva, S.; Kalantar-Nayestanaki, N.; Kiselev, O.; Kollmus, H.; Kozhuharov, C.; Krasznahorkay, A.; Kröll, Th.; Kuilman, M.; Litvinov, S.; Litvinov, Yu. A.; Mahjour-Shafiei, M.; Mutterer, M.; Nagae, D.; Najafi, M. A.; Nociforo, C.; Nolden, F.; Popp, U.; Rigollet, C.; Roy, S.; Scheidenberger, C.; von Schmid, M.; Steck, M.; Streicher, B.; Stuhl, L.; Thürauf, M.; Uesaka, T.; Weick, H.; Winfield, J. S.; Winters, D.; Woods, P. J.; Yamaguchi, T.; Yue, K.; Zenihiro, J.

2017-09-01

A novel method for measuring nuclear reactions in inverse kinematics with stored ion beams was successfully used to extract the nuclear-matter radius of 58Ni. The experiment was performed at the experimental heavy-ion storage ring at the GSI facility using a stored 58Ni beam at energies of 100 and 150 MeV/u and an internal helium gas-jet target. Elastically scattered α -recoils at low momentum transfers were measured with an in-ring detector system compatible with ultrahigh vacuum. Experimental angular distributions were fitted using density-dependent optical model potentials within the eikonal approximation. This permitted the extraction of the point-matter root-mean-square radius of 58Ni with an average value of 3.70(7) fm. Results from this work are in good agreement with several experiments performed in the past in normal kinematics. This pioneering experiment demonstrates a major breakthrough towards future investigations with far-from-stability stored beams using the present technique.

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

Sin, M.; Capote, R.; Herman, M. W.

Comprehensive calculations of cross sections for neutron-induced reactions on 232–237U targets are performed in this paper in the 10 keV–30 MeV incident energy range with the code EMPIRE–3.2 Malta. The advanced modelling and consistent calculation scheme are aimed at improving our knowledge of the neutron scattering and emission cross sections, and to assess the consistency of available evaluated libraries for light uranium isotopes. The reaction model considers a dispersive optical potential (RIPL 2408) that couples from five (even targets) to nine (odd targets) levels of the ground-state rotational band, and a triple-humped fission barrier with absorption in the wells describedmore » within the optical model for fission. A modified Lorentzian model (MLO) of the radiative strength function and Enhanced Generalized Superfluid Model nuclear level densities are used in Hauser-Feschbach calculations of the compound-nuclear decay that include width fluctuation corrections. The starting values for the model parameters are retrieved from RIPL. Excellent agreement with available experimental data for neutron emission and fission is achieved, giving confidence that the quantities for which there is no experimental information are also accurately predicted. Finally, deficiencies in existing evaluated libraries are highlighted.« less

Hybrid surgical guidance based on the integration of radionuclear and optical technologies

PubMed Central

Valdés-Olmos, Renato; Buckle, Tessa; Vidal-Sicart, Sergi

2016-01-01

With the evolution of imaging technologies and tracers, the applications for nuclear molecular imaging are growing rapidly. For example, nuclear medicine is increasingly being used to guide surgical resections in complex anatomical locations. Here, a future workflow is envisioned that uses a combination of pre-operative diagnostics, navigation and intraoperative guidance. Radioguidance can provide means for pre-operative and intraoperative identification of “hot” lesions, forming the basis of a virtual data set that can be used for navigation. Luminescence guidance has shown great potential in the intraoperative setting by providing optical feedback, in some cases even in real time. Both of these techniques have distinct drawbacks, which include inaccuracy in areas that contain a background signal (radioactivity) or a limited degree of signal penetration (luminescence). We, and others, have reasoned that hybrid/multimodal approaches that integrate the use of these complementary modalities may help overcome their individual weaknesses. Ultimately, this will lead to advancement of the field of interventional molecular imaging/image-guided surgery. In this review, an overview of clinically applied hybrid surgical guidance technologies is given, whereby the focus is placed on tracers and hardware. PMID:26943463

Towards automated segmentation of cells and cell nuclei in nonlinear optical microscopy.

PubMed

Medyukhina, Anna; Meyer, Tobias; Schmitt, Michael; Romeike, Bernd F M; Dietzek, Benjamin; Popp, Jürgen

2012-11-01

Nonlinear optical (NLO) imaging techniques based e.g. on coherent anti-Stokes Raman scattering (CARS) or two photon excited fluorescence (TPEF) show great potential for biomedical imaging. In order to facilitate the diagnostic process based on NLO imaging, there is need for an automated calculation of quantitative values such as cell density, nucleus-to-cytoplasm ratio, average nuclear size. Extraction of these parameters is helpful for the histological assessment in general and specifically e.g. for the determination of tumor grades. This requires an accurate image segmentation and detection of locations and boundaries of cells and nuclei. Here we present an image processing approach for the detection of nuclei and cells in co-registered TPEF and CARS images. The algorithm developed utilizes the gray-scale information for the detection of the nuclei locations and the gradient information for the delineation of the nuclear and cellular boundaries. The approach reported is capable for an automated segmentation of cells and nuclei in multimodal TPEF-CARS images of human brain tumor samples. The results are important for the development of NLO microscopy into a clinically relevant diagnostic tool. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Military Applications of Fiber Optics Technology

DTIC Science & Technology

1989-05-01

Research Projects Agency DNA Defense Nuclear Agency EMI Electromagnetic interference EMP Electromagnetic pulse FET Field effect transistor FOFA Follow...Organization SEED Self electro-optic effect device TBM Tactical ballistic missile TOW Tube launched, optically tracked, wire-guided UAV Unmanned aerial vehicle...systems, coupled with novel but effective transducing technology, have set the stage for a powerful class of fiber optic sensors. 8 Optical fibers have

Advances toward fully automated in vivo assessment of oral epithelial dysplasia by nuclear endomicroscopy-A pilot study.

PubMed

Liese, Jan; Winter, Karsten; Glass, Änne; Bertolini, Julia; Kämmerer, Peer Wolfgang; Frerich, Bernhard; Schiefke, Ingolf; Remmerbach, Torsten W

2017-11-01

Uncertainties in detection of oral epithelial dysplasia (OED) frequently result from sampling error especially in inflammatory oral lesions. Endomicroscopy allows non-invasive, "en face" imaging of upper oral epithelium, but parameters of OED are unknown. Mucosal nuclei were imaged in 34 toluidine blue-stained oral lesions with a commercial endomicroscopy. Histopathological diagnosis showed four biopsies in "dys-/neoplastic," 23 in "inflammatory," and seven in "others" disease groups. Strength of different assessment strategies of nuclear scoring, nuclear count, and automated nuclear analysis were measured by area under ROC curve (AUC) to identify histopathological "dys-/neoplastic" group. Nuclear objects from automated image analysis were visually corrected. Best-performing parameters of nuclear-to-image ratios were the count of large nuclei (AUC=0.986) and 6-nearest neighborhood relation (AUC=0.896), and best parameters of nuclear polymorphism were the count of atypical nuclei (AUC=0.996) and compactness of nuclei (AUC=0.922). Excluding low-grade OED, nuclear scoring and count reached 100% sensitivity and 98% specificity for detection of dys-/neoplastic lesions. In automated analysis, combination of parameters enhanced diagnostic strength. Sensitivity of 100% and specificity of 87% were seen for distances of 6-nearest neighbors and aspect ratios even in uncorrected objects. Correction improved measures of nuclear polymorphism only. The hue of background color was stronger than nuclear density (AUC=0.779 vs 0.687) to detect dys-/neoplastic group indicating that macroscopic aspect is biased. Nuclear-to-image ratios are applicable for automated optical in vivo diagnostics for oral potentially malignant disorders. Nuclear endomicroscopy may promote non-invasive, early detection of dys-/neoplastic lesions by reducing sampling error. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Anomalous electron spin decoherence in an optically pumped quantum dot

NASA Astrophysics Data System (ADS)

Shi, Xiaofeng; Sham, L. J.

2013-03-01

We study the nuclear-spin-fluctuation induced spin decoherence of an electron (SDE) in an optically pumped quantum dot. The SDE is computed in terms of the steady distribution of the nuclear field (SDNF) formed through the hyperfine interaction (HI) with two different nuclear species in the dot. A feedback loop between the optically driven electron spin and the nuclear spin ensemble determines the SDNF [W. Yang and L. J. Sham, Phy. Rev. B 85, 235319(2012)]. Different from that work and others reviewed therein, where a bilinear HI, SαIβ , between the electron (or hole) spin S and the nuclear spin I is used, we use an effective nonlinear interaction of the form SαIβIγ derived from the Fermi-contact HI. Our feedback loop forms a multi-peak SDNF in which the SDE shows remarkable collapses and revivals in nanosecond time scale. Such an anomalous SDE results from a quantum interference effect of the electron Larmor precession in a multi-peak effective magnetic field. In the presence of a bilinear HI that suppresses the nuclear spin fluctuation, the non-Markovian SDE persists whenever there are finite Fermi contact interactions between two or more kinds of nuclei and the electron in the quantum dot. This work is supported by NSF(PHY 1104446) and the US Army Research Office MURI award W911NF0910406.

Development and Application of Integrated Optical Sensors for Intense E-Field Measurement

PubMed Central

Zeng, Rong; Wang, Bo; Niu, Ben; Yu, Zhanqing

2012-01-01

The measurement of intense E-fields is a fundamental need in various research areas. Integrated optical E-field sensors (IOESs) have important advantages and are potentially suitable for intense E-field detection. This paper comprehensively reviews the development and applications of several types of IOESs over the last 30 years, including the Mach-Zehnder interferometer (MZI), coupler interferometer (CI) and common path interferometer (CPI). The features of the different types of IOESs are compared, showing that the MZI has higher sensitivity, the CI has a controllable optical bias, and the CPI has better temperature stability. More specifically, the improvement work of applying IOESs to intense E-field measurement is illustrated. Finally, typical uses of IOESs in the measurement of intense E-fields are demonstrated, including application areas such as E-fields with different frequency ranges in high-voltage engineering, simulated nuclear electromagnetic pulse in high-power electromagnetic pulses, and ion-accelerating field in high-energy physics. PMID:23112663

Excitation of the {sup 229m}Th nuclear isomer via resonance conversion in ionized atoms

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

Karpeshin, F. F., E-mail: fkarpeshin@gmail.com; Trzhaskovskaya, M. B.

2015-09-15

Pressing problems concerning the optical pumping of the 7.6-eV {sup 229m}Th nuclear isomer, which is a candidate for a new nuclear optical reference point for frequencies, are examined. Physics behind the mechanism of the two-photon optical pumping of the isomer is considered. It is shown that, irrespective of the pumping scheme, a dominant contribution comes, in accord with what was proven earlier for the 3.5-eV isomer, from the resonance 8s–7s transition. Details of an optimum experimental scheme are discussed. It is shown that, after isomer excitation, the atom involved remains with a high probability in an excited state at anmore » energy of about 0.5 eV rather than in the ground state, the required energy of the two photons being equal to the energy of the nuclear level plus the energy of the lowest 7s state of the atom. The estimated pumping time is about 1.5 s in the case where the field strength of each laser is 1 V/cm.« less

Excitation of the 229 m Th nuclear isomer via resonance conversion in ionized atoms

NASA Astrophysics Data System (ADS)

Karpeshin, F. F.; Trzhaskovskaya, M. B.

2015-09-01

Pressing problems concerning the optical pumping of the 7.6-eV 229 m Th nuclear isomer, which is a candidate for a new nuclear optical reference point for frequencies, are examined. Physics behind the mechanism of the two-photon optical pumping of the isomer is considered. It is shown that, irrespective of the pumping scheme, a dominant contribution comes, in accord with what was proven earlier for the 3.5-eV isomer, from the resonance 8 s-7 s transition. Details of an optimum experimental scheme are discussed. It is shown that, after isomer excitation, the atom involved remains with a high probability in an excited state at an energy of about 0.5 eV rather than in the ground state, the required energy of the two photons being equal to the energy of the nuclear level plus the energy of the lowest 7 s state of the atom. The estimated pumping time is about 1.5 s in the case where the field strength of each laser is 1 V/cm.

Determination of the η‧-nucleus optical potential

NASA Astrophysics Data System (ADS)

Nanova, M.; Metag, V.; Paryev, E. Ya.; Bayadilov, D.; Bantes, B.; Beck, R.; Beloglazov, Y. A.; Böse, S.; Brinkmann, K.-T.; Challand, Th.; Crede, V.; Dahlke, T.; Dietz, F.; Drexler, P.; Eberhardt, H.; Elsner, D.; Ewald, R.; Fornet-Ponse, K.; Friedrich, S.; Frommberger, F.; Funke, Ch.; Gottschall, M.; Gridnev, A.; Grüner, M.; Gutz, E.; Hammann, Ch.; Hammann, D.; Hannappel, J.; Hartmann, J.; Hillert, W.; Hoffmeister, P.; Honisch, Ch.; Jaegle, I.; Kaiser, D.; Kalinowsky, H.; Kammer, S.; Keshelashvili, I.; Kleber, V.; Klein, F.; Klempt, E.; Krusche, B.; Lang, M.; Lopatin, I. V.; Maghrbi, Y.; Makonyi, K.; Müller, J.; Odenthal, T.; Piontek, D.; Schaepe, S.; Schmidt, Ch.; Schmieden, H.; Schmitz, R.; Seifen, T.; Thiel, A.; Thoma, U.; van Pee, H.; Walther, D.; Wendel, Ch.; Wiedner, U.; Wilson, A.; Winnebeck, A.; Zenke, F.

2013-12-01

The excitation function and momentum distribution of η‧ mesons have been measured in photon induced reactions on 12C in the energy range of 1250-2600 MeV. The experiment was performed with tagged photon beams from the ELSA electron accelerator using the Crystal Barrel and TAPS detectors. The data are compared to model calculations to extract information on the sign and magnitude of the real part of the η‧-nucleus potential. Within the model, the comparison indicates an attractive potential of -(37±10(stat)±10(syst)) MeV depth at normal nuclear matter density. Since the modulus of this depth is larger than the modulus of the imaginary part of the η‧-nucleus potential of -(10±2.5) MeV, determined by transparency ratio measurements, a search for resolved η‧-bound states appears promising.

Feasibility of Optical Instruments Based on Multiaperture Optics.

DTIC Science & Technology

1984-10-16

system may be configured. The optical elements may be nonimaging concentrators (light horns), the field of view (FOV) of which may be controlled by a...RD-RI58 868 FEASIBILITY OF OPTICAL INSTRUMENTS BASED ON i/I MULTIAPERTURE OPTICS (U) FLORIDA UNIV GAINESVILLE DEPT OF NUCLEAR ENGINEERING SCIENCES J D...d Subtitle) 5. TYPE OF REPORT & PERIOD COVERED ’ 0 Feasibility of Optical Instruments Based on Final Report * CD Multiaperature Optics 615/83 to 9/30

Analysis system of submicron particle tracks in the fine-grained nuclear emulsion by a combination of hard x-ray and optical microscopy

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

Naka, T., E-mail: naka@flab.phys.nagoya-u.ac.jp; Institute for Advanced Research, Nagoya University, Aichi 464-8602; Asada, T.

Analyses of nuclear emulsion detectors that can detect and identify charged particles or radiation as tracks have typically utilized optical microscope systems because the targets have lengths from several μm to more than 1000 μm. For recent new nuclear emulsion detectors that can detect tracks of submicron length or less, the current readout systems are insufficient due to their poor resolution. In this study, we developed a new system and method using an optical microscope system for rough candidate selection and the hard X-ray microscope system at SPring-8 for high-precision analysis with a resolution of better than 70 nm resolution.more » Furthermore, we demonstrated the analysis of submicron-length tracks with a matching efficiency of more than 99% and position accuracy of better than 5 μm. This system is now running semi-automatically.« less

Spinning angle optical calibration apparatus

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

Beer, S.K.; Pratt, H.R. II.

1989-09-12

An optical calibration apparatus is provided for calibrating and reproducing spinning angles in cross-polarization, nuclear magnetic resonance spectroscopy. An illuminated magnifying apparatus enables optical setting and accurate reproducing of spinning magic angles in cross-polarization, nuclear magnetic resonance spectroscopy experiments. A reference mark scribed on an edge of a spinning angle test sample holder is illuminated by a light source and viewed through a magnifying scope. When the magic angle of a sample material used as a standard is attained by varying the angular position of the sample holder, the coordinate position of the reference mark relative to a graduation ormore » graduations on a reticle in the magnifying scope is noted. Thereafter, the spinning magic angle of a test material having similar nuclear properties to the standard is attained by returning the sample holder back to the originally noted coordinate position. 2 figs.« less

Discretization of the total magnetic field by the nuclear spin bath in fluorine-doped ZnSe.

PubMed

Zhukov, E A; Kirstein, E; Kopteva, N E; Heisterkamp, F; Yugova, I A; Korenev, V L; Yakovlev, D R; Pawlis, A; Bayer, M; Greilich, A

2018-05-16

The coherent spin dynamics of fluorine donor-bound electrons in ZnSe induced by pulsed optical excitation is studied in a perpendicular applied magnetic field. The Larmor precession frequency serves as a measure for the total magnetic field exerted onto the electron spins and, surprisingly, does not increase linearly with the applied field, but shows a step-like behavior with pronounced plateaus, given by multiples of the laser repetition rate. This discretization occurs by a feedback mechanism in which the electron spins polarize the nuclear spins, which in turn generate a local Overhauser field adjusting the total magnetic field accordingly. Varying the optical excitation power, we can control the plateaus, in agreement with our theoretical model. From this model, we trace the observed discretization to the optically induced Stark field, which causes the dynamic nuclear polarization.

Dual-mode imaging with radiolabeled gold nanorods

NASA Astrophysics Data System (ADS)

Agarwal, Ashish; Shao, Xia; Rajian, Justin R.; Zhang, Huanan; Chamberland, David L.; Kotov, Nicholas A.; Wang, Xueding

2011-05-01

Many nanoparticle contrast agents have difficulties with deep tissue and near-bone imaging due to limited penetration of visible photons in the body and mineralized tissues. We are looking into the possibility of mediating this problem while retaining the capabilities of the high spatial resolution associated with optical imaging. As such, the potential combination of emerging photoacoustic imaging and nuclear imaging in monitoring of antirheumatic drug delivery by using a newly developed dual-modality contrast agent is investigated. The contrast agent is composed of gold nanorods (GNRs) conjugated to the tumor necrosis factor (TNF-α) antibody and is subsequently radiolabeled by 125I. ELISA experiments designed to test TNF-α binding are performed to prove the specificity and biological activity of the radiolabeled conjugated contrast agent. Photoacoustic and nuclear imaging are performed to visualize the distribution of GNRs in articular tissues of the rat tail joints in situ. Findings from the two imaging modalities correspond well with each other in all experiments. Our system can image GNRs down to a concentration of 10 pM in biological tissues and with a radioactive label of 5 μCi. This study demonstrates the potential of combining photoacoustic and nuclear imaging modalities through one targeted contrast agent for noninvasive monitoring of drug delivery as well as deep and mineralized tissue imaging.

Spin-lattice relaxation of optically polarized nuclei in p -type GaAs

NASA Astrophysics Data System (ADS)

Kotur, M.; Dzhioev, R. I.; Vladimirova, M.; Cherbunin, R. V.; Sokolov, P. S.; Yakovlev, D. R.; Bayer, M.; Suter, D.; Kavokin, K. V.

2018-04-01

Spin-lattice relaxation of the nuclear spin system in p -type GaAs is studied using a three-stage experimental protocol including optical pumping and measuring the difference of the nuclear spin polarization before and after a dark interval of variable length. This method allows us to measure the spin-lattice relaxation time T1 of optically pumped nuclei "in the dark," that is, in the absence of illumination. The measured T1 values fall into the subsecond time range, being three orders of magnitude shorter than in earlier studied n -type GaAs. The drastic difference is further emphasized by magnetic-field and temperature dependencies of T1 in p -GaAs, showing no similarity to those in n -GaAs. This unexpected behavior finds its explanation in the spatial selectivity of the optical pumping in p -GaAs, that is only efficient in the vicinity of shallow donors, together with the quadrupole relaxation of nuclear spins, which is induced by electric fields within closely spaced donor-acceptor pairs. The developed theoretical model explains the whole set of experimental results.

Quantum entanglement analysis of an optically excited coupling of two nuclear spins via a mediator: Combining the quantum concurrence and negativity

NASA Astrophysics Data System (ADS)

Fu, Chenghua; Hu, Zhanning

2018-03-01

In this paper, we investigate the characteristics of the nuclear spin entanglement generated by an intermedium with an optically excited triplet. Significantly, the interaction between the two nuclear spins presents to be a direct XY coupling in each of the effective subspace Hamiltonians which are obtained by applying a transformation on the natural Hamiltonian. The quantum concurrence and negativity are discussed to quantitatively describe the quantum entanglement, and a comparison between them can reveal the nature of their relationship. An innovative general equation describing the relationship between the concurrence and negativity is explicitly obtained.

Present Practice And Perceived Needs-Managing Diagnostic Images

NASA Astrophysics Data System (ADS)

Vanden Brink, John A.

1982-01-01

With the advent of digital radiography and the installed base of CT, Nuclear Medicine and Ultrasound Scanners numbering in the thousands and the potential of NMR, the market potential for the electronic management of digital images is perhaps one of the most exciting, fastest growing (and most ill defined) fields in medicine today. New technology in optical data storage, electronic transmission, image reproduction, microprocessing, automation and software development provide the promise of a whole new generation of products which will simplify and enhance the diagnostic process (thereby hopefully improving diagnostic accuracy), enable implementation of archival review in a practical sense, expand the availability of diagnostic data and lower the cost/case by at least an order of magnitude.

(16) {C}16C-elastic scattering examined using several models at different energies

NASA Astrophysics Data System (ADS)

El-hammamy, M. N.; Attia, A.

2018-05-01

In the present paper, the first results concerning the theoretical analysis of the ^{16}C + p reaction by investigating two elastic scattering angular distributions measured at high energy compared to low energy for this system are reported. Several models for the real part of the nuclear potential are tested within the optical model formalism. The imaginary potential has a Woods-Saxon shape with three free parameters. Two types of density distribution and three different cluster structures for ^{16}C are assumed in the analysis. The results are compared with each other as well as with the experimental data to give evidence of the importance of these studied items.

Determination of the real part of the η'-Nb optical potential

NASA Astrophysics Data System (ADS)

Nanova, M.; Friedrich, S.; Metag, V.; Paryev, E. Ya.; Afzal, F. N.; Bayadilov, D.; Beck, R.; Becker, M.; Böse, S.; Brinkmann, K.-T.; Crede, V.; Elsner, D.; Frommberger, F.; Grüner, M.; Gutz, E.; Hammann, Ch.; Hannappel, J.; Hartmann, J.; Hillert, W.; Hoffmeister, P.; Honisch, Ch.; Jude, T.; Kalischewski, F.; Keshelashvili, I.; Klein, F.; Koop, K.; Krusche, B.; Lang, M.; Makonyi, K.; Messi, F.; Müller, J.; Müllers, J.; Piontek, D.-M.; Rostomyan, T.; Schaab, D.; Schmidt, C.; Schmieden, H.; Schmitz, R.; Seifen, T.; Sowa, C.; Spieker, K.; Thiel, A.; Thoma, U.; Triffterer, T.; Urban, M.; van Pee, H.; Walther, D.; Wendel, C.; Werthmüller, D.; Wiedner, U.; Wilson, A.; Witthauer, L.; Wunderlich, Y.; Zaunick, H.-G.; Cbelsa/Taps Collaboration

2016-08-01

The excitation function and momentum distribution of η' mesons have been measured in photoproduction off 93Nb in the energy range of 1.2-2.9 GeV. The experiment has been performed with the combined Crystal Barrel and MiniTAPS detector system, using tagged photon beams from the ELSA electron accelerator. Information on the sign and magnitude of the real part of the η'-Nb potential has been extracted from a comparison of the data with model calculations. An attractive potential of -(41 ±10 (stat )±15 (syst )) MeV depth at normal nuclear matter density is deduced within model uncertainties. This value is consistent with the potential depth of -(37 ±10 (stat )±10 (syst )) MeV obtained in an earlier measurement for a light nucleus (carbon). This relatively shallow η'-nucleus potential will make the search for η'-nucleus bound states more difficult.

Histone deacetylase expression patterns in developing murine optic nerve

PubMed Central

2014-01-01

Background Histone deacetylases (HDACs) play important roles in glial cell development and in disease states within multiple regions of the central nervous system. However, little is known about HDAC expression or function within the optic nerve. As a first step in understanding the role of HDACs in optic nerve, this study examines the spatio-temporal expression patterns of methylated histone 3 (K9), acetylated histone 3 (K18), and HDACs 1–6 and 8–11 in the developing murine optic nerve head. Results Using RT-qPCR, western blot and immunofluorescence, three stages were analyzed: embryonic day 16 (E16), when astrocyte precursors are found in the optic stalk, postnatal day 5 (P5), when immature astrocytes and oligodendrocytes are found throughout the optic nerve, and P30, when optic nerve astrocytes and oligodendrocytes are mature. Acetylated and methylated histone H3 immunoreactivity was co-localized in the nuclei of most SOX2 positive glia within the optic nerve head and adjacent optic nerve at all developmental stages. HDACs 1–11 were expressed in the optic nerve glial cells at all three stages of optic nerve development in the mouse, but showed temporal differences in overall levels and subcellular localization. HDACs 1 and 2 were predominantly nuclear throughout optic nerve development and glial cell maturation. HDACs 3, 5, 6, 8, and 11 were predominantly cytoplasmic, but showed nuclear localization in at least one stage of optic nerve development. HDACs 4, 9 and10 were predominantly cytoplasmic, with little to no nuclear expression at any time during the developmental stages examined. Conclusions Our results showing that HDACs 1, 2, 3, 5, 6, 8, and 11 were each localized to the nuclei of SOX2 positive glia at some stages of optic nerve development and maturation and extend previous reports of HDAC expression in the aging optic nerve. These HDACs are candidates for further research to understand how chromatin remodeling through acetylation, deacetylation and methylation contributes to glial development as well as their injury response. PMID:25011550

Nuclear spin polarized H and D by means of spin-exchange optical pumping

NASA Astrophysics Data System (ADS)

Stenger, Jörn; Grosshauser, Carsten; Kilian, Wolfgang; Nagengast, Wolfgang; Ranzenberger, Bernd; Rith, Klaus; Schmidt, Frank

1998-01-01

Optically pumped spin-exchange sources for polarized hydrogen and deuterium atoms have been demonstrated to yield high atomic flow and high electron spin polarization. For maximum nuclear polarization the source has to be operated in spin temperature equilibrium, which has already been demonstrated for hydrogen. In spin temperature equilibrium the nuclear spin polarization PI equals the electron spin polarization PS for hydrogen and is even larger than PS for deuterium. We discuss the general properties of spin temperature equilibrium for a sample of deuterium atoms. One result are the equations PI=4PS/(3+PS2) and Pzz=PSṡPI, where Pzz is the nuclear tensor polarization. Furthermore we demonstrate that the deuterium atoms from our source are in spin temperature equilibrium within the experimental accuracy.

Optical Imaging of Ionizing Radiation from Clinical Sources.

PubMed

Shaffer, Travis M; Drain, Charles Michael; Grimm, Jan

2016-11-01

Nuclear medicine uses ionizing radiation for both in vivo diagnosis and therapy. Ionizing radiation comes from a variety of sources, including x-rays, beam therapy, brachytherapy, and various injected radionuclides. Although PET and SPECT remain clinical mainstays, optical readouts of ionizing radiation offer numerous benefits and complement these standard techniques. Furthermore, for ionizing radiation sources that cannot be imaged using these standard techniques, optical imaging offers a unique imaging alternative. This article reviews optical imaging of both radionuclide- and beam-based ionizing radiation from high-energy photons and charged particles through mechanisms including radioluminescence, Cerenkov luminescence, and scintillation. Therapeutically, these visible photons have been combined with photodynamic therapeutic agents preclinically for increasing therapeutic response at depths difficult to reach with external light sources. Last, new microscopy methods that allow single-cell optical imaging of radionuclides are reviewed. © 2016 by the Society of Nuclear Medicine and Molecular Imaging, Inc.

Lattice damage assessment and optical waveguide properties in LaAlO3 single crystal irradiated with swift Si ions

NASA Astrophysics Data System (ADS)

Liu, Y.; Crespillo, M. L.; Huang, Q.; Wang, T. J.; Liu, P.; Wang, X. L.

2017-02-01

As one of the representative ABO3 perovskite-structured oxides, lanthanum aluminate (LaAlO3) crystal has emerged as one of the most valuable functional-materials, and has attracted plenty of fundamental research and promising applications in recent years. Electronic, magnetic, optical and other properties of LaAlO3 strongly depend on its crystal structure, which could be strongly modified owing to the nuclear or electronic energy loss deposited in an ion irradiation environment and, therefore, significantly affecting the performance of LaAlO3-based devices. In this work, utilizing swift (tens of MeV) Si-ion irradiation, the damage behavior of LaAlO3 crystal induced by nuclear or electronic energy loss has been studied in detail utilizing complementary characterization techniques. Differing from other perovskite-structured crystals in which the electronic energy loss could lead to the formation of an amorphous region based on the thermal spike mechanism, in this case, intense electronic energy loss in LaAlO3 will not induce any obvious structural damage. The effects of ion irradiation on the mechanical properties, including hardness increase and elastic modulus decrease, have been confirmed. On the other hand, considering the potential applications of LaAlO3 in the field of integrated optoelectronics, the optical-waveguide properties of the irradiation region have been studied. The significant correspondence (symmetrical inversion) between the iWKB-reconstructed refractive-index profile and SRIM-simulated dpa profile further proves the effects (irradiation-damage production and refractive-index decrease) of nuclear energy loss during the swift-ion penetration process in LaAlO3 crystal. In the case of the rather-thick damage layer produced by swift-ion irradiation, obtaining a damage profile will be constrained owing to the analysis-depth limitation of the characterization techniques (RBS/channeling), and our analysis process (optical guided-mode measurement and subsequent refractive-index-profile reconstruction) also provides a new approach to study the damage behavior (damage profile) once the functional relationship between the refractive index and lattice disorder for the specific material could be determined.

Nuclear Winter: Global Consequences of Multiple Nuclear Explosions

NASA Astrophysics Data System (ADS)

Turco, R. P.; Toon, O. B.; Ackerman, T. P.; Pollack, J. B.; Sagan, Carl

1983-12-01

The potential global atmospheric and climatic consequences of nuclear war are investigated using models previously developed to study the effects of volcanic eruptions. Although the results are necessarily imprecise, due to a wide range of possible scenarios and uncertainty in physical parameters, the most probable first-order effects are serious. Significant hemispherical attenuation of the solar radiation flux and subfreezing land temperatures may be caused by fine dust raised in high-yield nuclear surface bursts and by smoke from city and forest fires ignited by airbursts of all yields. For many simulated exchanges of several thousand megatons, in which dust and smoke are generated and encircle the earth within 1 to 2 weeks, average light levels can be reduced to a few percent of ambient and land temperatures can reach -15 degrees to -25 degrees C. The yield threshold for major optical and climatic consequences may be very low: only about 100 megatons detonated over major urban centers can create average hemispheric smoke optical depths greater than 2 for weeks and, even in summer, subfreezing land temperatures for months. In a 5000-megaton war, at northern mid-latitude sites remote from targets, radioactive fallout on time scales of days to weeks can lead to chronic mean doses of up to 50 rads from external whole-body gamma-ray exposure, with a likely equal or greater internal dose from biologically active radionuclides. Large horizontal and vertical temperature gradients caused by absorption of sunlight in smoke and dust clouds may greatly accelerate transport of particles and radioactivity from the Northern Hemisphere to the Southern Hemisphere. When combined with the prompt destruction from nuclear blast, fires, and fallout and the later enhancement of solar ultraviolet radiation due to ozone depletion, long-term exposure to cold, dark, and radioactivity could pose a serious threat to human survivors and to other species.

Unusual Attenuation Recovery Process After Fiber Optic Cable Irradiation

NASA Astrophysics Data System (ADS)

Konečná, Z.; Plaček, V.; Havránek, P.

2017-11-01

At present, the number of optical cables in nuclear power plants has been increasing. Fiber optic cables are commonly used at nuclear power plants in instrumentation and control systems but they are usually used in environments without radiation. Nevertheless, currently, the number of applications in NPP containment with radiation is increasing. One of the most prevalent effects of radiation exposure is an increase of signal attenuation (signal loss). This is the result of fiber darkening due to radiation exposure and it is the main limitation factor in application of fiber optics in radiation environment. However, after the irradiation, the fiber optics go through a “recovery process” during which the optical properties improve again; i.e. attenuation decreases. However, we have found cable, where the expected healing process after few days changed its trend and the attenuation increased again to a value well above the attenuation just after the irradiation. This paper describes experiments that were carried out to explain this unusual recovery behaviour.

Estimation of M 1 scissors mode strength for deformed nuclei in the medium- to heavy-mass region by statistical Hauser-Feshbach model calculations

DOE PAGES

Mumpower, Matthew Ryan; Kawano, Toshihiko; Ullmann, John Leonard; ...

2017-08-17

Radiative neutron capture is an important nuclear reaction whose accurate description is needed for many applications ranging from nuclear technology to nuclear astrophysics. The description of such a process relies on the Hauser-Feshbach theory which requires the nuclear optical potential, level density, and γ-strength function as model inputs. It has recently been suggested that the M1 scissors mode may explain discrepancies between theoretical calculations and evaluated data. We explore statistical model calculations with the strength of the M1 scissors mode estimated to be dependent on the nuclear deformation of the compound system. We show that the form of the M1more » scissors mode improves the theoretical description of evaluated data and the match to experiment in both the fission product and actinide regions. Since the scissors mode occurs in the range of a few keV to a few MeV, it may also impact the neutron capture cross sections of neutron-rich nuclei that participate in the rapid neutron capture process of nucleosynthesis. As a result, we comment on the possible impact to nucleosynthesis by evaluating neutron capture rates for neutron-rich nuclei with the M1 scissors mode active.« less

Optical detection of special nuclear materials: an alternative approach for standoff and remote sensing

NASA Astrophysics Data System (ADS)

Johnson, J. Bruce; Reeve, S. W.; Burns, W. A.; Allen, Susan D.

2010-04-01

Termed Special Nuclear Material (SNM) by the Atomic Energy Act of 1954, fissile materials, such as 235U and 239Pu, are the primary components used to construct modern nuclear weapons. Detecting the clandestine presence of SNM represents an important capability for Homeland Security. An ideal SNM sensor must be able to detect fissile materials present at ppb levels, be able to distinguish between the source of the detected fissile material, i.e., 235U, 239Pu, 233U or other fission source, and be able to perform the discrimination in near real time. A sensor with such capabilities would provide not only rapid identification of a threat but, ultimately, information on the potential source of the threat. For example, current detection schemes for monitoring clandestine nuclear testing and nuclear fuel reprocessing to provide weapons grade fissile material rely largely on passive air sampling combined with a subsequent instrumental analysis or some type of wet chemical analysis of the collected material. It would be highly useful to have a noncontact method of measuring isotopes capable of providing forensic information rapidly at ppb levels of detection. Here we compare the use of Kr, Xe and I as "canary" species for distinguishing between 235U and 239Pu fission sources by spectroscopic methods.

First results from GeMS/GSAOI for project SUNBIRD: Supernovae UNmasked By Infra-Red Detection

NASA Astrophysics Data System (ADS)

Kool, E. C.; Ryder, S.; Kankare, E.; Mattila, S.; Reynolds, T.; McDermid, R. M.; Pérez-Torres, M. A.; Herrero-Illana, R.; Schirmer, M.; Efstathiou, A.; Bauer, F. E.; Kotilainen, J.; Väisänen, P.; Baldwin, C.; Romero-Cañizales, C.; Alberdi, A.

2018-02-01

Core collapse supernova (CCSN) rates suffer from large uncertainties as many CCSNe exploding in regions of bright background emission and significant dust extinction remain unobserved. Such a shortfall is particularly prominent in luminous infrared galaxies (LIRGs), which have high star formation (and thus CCSN) rates and host bright and crowded nuclear regions, where large extinctions and reduced search detection efficiency likely lead to a significant fraction of CCSNe remaining undiscovered. We present the first results of project SUNBIRD (Supernovae UNmasked By Infra-Red Detection), where we aim to uncover CCSNe that otherwise would remain hidden in the complex nuclear regions of LIRGs, and in this way improve the constraints on the fraction that is missed by optical seeing-limited surveys. We observe in the near-infrared 2.15 μm Ks-band, which is less affected by dust extinction compared to the optical, using the multiconjugate adaptive optics imager GeMS/GSAOI on Gemini South, allowing us to achieve a spatial resolution that lets us probe close in to the nuclear regions. During our pilot program and subsequent first full year we have discovered three CCSNe and one candidate with projected nuclear offsets as small as 200 pc. When compared to the total sample of LIRG CCSNe discovered in the near-IR and optical, we show that our method is singularly effective in uncovering CCSNe in nuclear regions and we conclude that the majority of CCSNe exploding in LIRGs are not detected as a result of dust obscuration and poor spatial resolution.

Multiphoton microscopy as a diagnostic imaging modality for pancreatic neoplasms without hematoxylin and eosin stains

NASA Astrophysics Data System (ADS)

Chen, Youting; Chen, Jing; Chen, Hong; Hong, Zhipeng; Zhu, Xiaoqin; Zhuo, Shuangmu; Chen, Yanling; Chen, Jianxin

2014-09-01

Hematoxylin and eosin (H&E) staining of tissue samples is the standard approach in histopathology for imaging and diagnosing cancer. Recent reports have shown that multiphoton microscopy (MPM) provides better sample interface with single-cell resolution, which enhances traditional H&E staining and offers a powerful diagnostic tool with potential applications in oncology. The purpose of this study was to further expand the versatility of MPM by establishing the optical parameters required for imaging unstained histological sections of pancreatic neoplasms, thereby providing an efficient and environmentally sustainable alternative to H&E staining while improving the accuracy of pancreatic cancer diagnoses. We found that the high-resolution MPM images clearly distinguish between the structure of normal pancreatic tissues compared with pancreatic neoplasms in unstained histological sections, and discernable differences in tissue architecture and cell morphology between normal versus tumorigenic cells led to enhanced optical diagnosis of cancerous tissue. Moreover, quantitative assessment of the cytomorphological features visualized from MPM images showed significant differences in the nuclear-cytoplasmic ratios of pancreatic neoplasms compared with normal pancreas, as well as further distinguished pancreatic malignant tumors from benign tumors. These results indicate that the MPM could potentially serve as an optical tool for the diagnosis of pancreatic neoplasms in unstained histological sections.

FALCON reactor-pumped laser description and program overview

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

None

1989-12-01

The FALCON (Fission Activated Laser CONcept) reactor-pumped laser program at Sandia National Laboratories is examining the feasibility of high-power systems pumped directly by the energy from a nuclear reactor. In this concept we use the highly energetic fission fragments from neutron induced fission to excite a large volume laser medium. This technology has the potential to scale to extremely large optical power outputs in a primarily self-powered device. A laser system of this type could also be relatively compact and capable of long run times without refueling.

Characterizing the Utility and Limitations of Repurposing an Open-Field Optical Imaging Device for Fluorescence-Guided Surgery in Head and Neck Cancer Patients.

PubMed

Moore, Lindsay S; Rosenthal, Eben L; Chung, Thomas K; de Boer, Esther; Patel, Neel; Prince, Andrew C; Korb, Melissa L; Walsh, Erika M; Young, E Scott; Stevens, Todd M; Withrow, Kirk P; Morlandt, Anthony B; Richman, Joshua S; Carroll, William R; Zinn, Kurt R; Warram, Jason M

2017-02-01

The purpose of this study was to assess the potential of U.S. Food and Drug Administration-cleared devices designed for indocyanine green-based perfusion imaging to identify cancer-specific bioconjugates with overlapping excitation and emission wavelengths. Recent clinical trials have demonstrated potential for fluorescence-guided surgery, but the time and cost of the approval process may impede clinical translation. To expedite this translation, we explored the feasibility of repurposing existing optical imaging devices for fluorescence-guided surgery. Consenting patients (n = 15) scheduled for curative resection were enrolled in a clinical trial evaluating the safety and specificity of cetuximab-IRDye800 (NCT01987375). Open-field fluorescence imaging was performed preoperatively and during the surgical resection. Fluorescence intensity was quantified using integrated instrument software, and the tumor-to-background ratio characterized fluorescence contrast. In the preoperative clinic, the open-field device demonstrated potential to guide preoperative mapping of tumor borders, optimize the day of surgery, and identify occult lesions. Intraoperatively, the device demonstrated robust potential to guide surgical resections, as all peak tumor-to-background ratios were greater than 2 (range, 2.2-14.1). Postresection wound bed fluorescence was significantly less than preresection tumor fluorescence (P < 0.001). The repurposed device also successfully identified positive margins. The open-field imaging device was successfully repurposed to distinguish cancer from normal tissue in the preoperative clinic and throughout surgical resection. This study illuminated the potential for existing open-field optical imaging devices with overlapping excitation and emission spectra to be used for fluorescence-guided surgery. © 2017 by the Society of Nuclear Medicine and Molecular Imaging.

Optical model calculations of heavy-ion target fragmentation

NASA Technical Reports Server (NTRS)

Townsend, L. W.; Wilson, J. W.; Cucinotta, F. A.; Norbury, J. W.

1986-01-01

The fragmentation of target nuclei by relativistic protons and heavy ions is described within the context of a simple abrasion-ablation-final-state interaction model. Abrasion is described by a quantum mechanical formalism utilizing an optical model potential approximation. Nuclear charge distributions of the excited prefragments are calculated by both a hypergeometric distribution and a method based upon the zero-point oscillations of the giant dipole resonance. Excitation energies are estimated from the excess surface energy resulting from the abrasion process and the additional energy deposited by frictional spectator interactions of the abraded nucleons. The ablation probabilities are obtained from the EVA-3 computer program. Isotope production cross sections for the spallation of copper targets by relativistic protons and for the fragmenting of carbon targets by relativistic carbon, neon, and iron projectiles are calculated and compared with available experimental data.

Feedback control for manipulating magnetization in spin-exchange optical pumping system

NASA Astrophysics Data System (ADS)

Zhang, Ke; Li, Jun; Jiang, Min; Zhao, Nan; Peng, XinHua

2018-08-01

Control of magnetization plays an important role in the scientific and technological field of manipulating spin systems. In this work, we study the problem of manipulating nuclear magnetization in the spin-exchange optical pumping system, including accelerating the recovery of nuclear polarization and fixing it on a specific desired state. A real-time feedback control strategy is exploited here. We have also done some numerical simulations, with the results clearly demonstrating the effectiveness of our method, that the nuclear magnetization is able to be driven towards the equilibrium state at a much faster speed and also can be stabilized to a target state. We expect that our feedback control method can find applications in gyro experiments.

Spinning angle optical calibration apparatus

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

Beer, S.K.; Pratt, H.R.

1991-02-26

This patent describes an optical calibration apparatus provided for calibrating and reproducing spinning angles in cross-polarization, nuclear magnetic resonance spectroscopy. An illuminated magnifying apparatus enables optical setting an accurate reproducing of spinning magic angles in cross-polarization, nuclear magnetic resonance spectroscopy experiments. A reference mark scribed on an edge of a spinning angle test sample holder is illuminated by a light source and viewed through a magnifying scope. When the magic angle of a sample material used as a standard is attained by varying the angular position of the sample holder, the coordinate position of the reference mark relative to amore » graduation or graduations on a reticle in the magnifying scope is noted.« less

Overview of radiation effects research in photonics

NASA Astrophysics Data System (ADS)

Webb, Robert C.; Cohn, Lewis M.; Taylor, Edward W.; Greenwell, Roger A.

1995-05-01

A brief overview of ongoing radiation effects research in photonics is presented focusing on integrated optic and acousto-optic components. A short summary of radiation-induced effects in electro-optic modulators, detector arrays, and other photonic technologies is presented along with extensive references. The coordinated radiation effects studies among researchers within the Tri-Service Organizations and international experimental teams are beginning to demonstrate consistent measurements of radiation-induced effects in photonic components and confirming earlier reported data. This paper will present an overview of these coordinated investigations and focus on key research being conducted with the AFMC Phillips Laboratory, Naval Research Laboratory, Defence Nuclear Agency, NATO Nuclear Effects Task Group, and the Tri-Service Photonics Coordinating Committee.

Selective sensitivity of Mueller imaging for tissue scattering over absorption changes in cancer mimicking phantoms

NASA Astrophysics Data System (ADS)

Fathima, Adeeba; Sharma B. S., Mahima; N., Sujatha

2018-03-01

Tissue characterization using optical polarimetry, especially Mueller imaging is receiving sustained interest due to its potential in achieving optical contrast between normal and malignant variations. This is particularly important in identifying the margin of malignant growth in suspected tissue regions for accurate surgical removal, or in aiding the sampling procedure during biopsy. The sensitivity of Mueller matrix derived depolarization index to the combined effects of changes in scattering and absorption occurring in a cancerous growth is illustrated in this study. Depolarization imaging is shown to be useful in demarcating the boundary of two regions of differing optical properties using a tissue phantom, modeled according to the changes expected during cancerous growth in tissue. Tissue scattering and absorption are expected to generally increase with the nuclear size change and crowding as well as angiogenesis associated with malignancy. We have observed that there is selective sensitivity for the Mueller elements and derived depolarization index to tissue scattering over absorption in the object field. Although the scattering and absorption are expected to increase and decrease depolarization respectively, the optical contrast of Mueller images and the derived depolarization index between normal and cancerous tissue is found appreciable in this region.

229Thorium-doped calcium fluoride for nuclear laser spectroscopy.

PubMed

Dessovic, P; Mohn, P; Jackson, R A; Winkler, G; Schreitl, M; Kazakov, G; Schumm, T

2014-03-12

The (229)thorium isotope presents an extremely low-energy isomer state of the nucleus which is expected around 7.8 eV, in the vacuum ultraviolet (VUV) regime. This unique system may bridge between atomic and nuclear physics, enabling coherent manipulation and precision spectroscopy of nuclear quantum states using laser light. It has been proposed to implant (229)thorium into VUV transparent crystal matrices to facilitate laser spectroscopy and possibly realize a solid-state nuclear clock. In this work, we validate the feasibility of this approach by computer modelling of thorium doping into calcium fluoride single crystals. Using atomistic modelling and full electronic structure calculations, we find a persistent large band gap and no additional electronic levels emerging in the middle of the gap due to the presence of the dopant, which should allow direct optical interrogation of the nuclear transition.Based on the electronic structure, we estimate the thorium nuclear quantum levels within the solid-state environment. Precision laser spectroscopy of these levels will allow the study of a broad range of crystal field effects, transferring Mössbauer spectroscopy into the optical regime.

Theoretical model of dynamic spin polarization of nuclei coupled to paramagnetic point defects in diamond and silicon carbide

NASA Astrophysics Data System (ADS)

Ivády, Viktor; Szász, Krisztián; Falk, Abram L.; Klimov, Paul V.; Christle, David J.; Janzén, Erik; Abrikosov, Igor A.; Awschalom, David D.; Gali, Adam

2015-09-01

Dynamic nuclear spin polarization (DNP) mediated by paramagnetic point defects in semiconductors is a key resource for both initializing nuclear quantum memories and producing nuclear hyperpolarization. DNP is therefore an important process in the field of quantum-information processing, sensitivity-enhanced nuclear magnetic resonance, and nuclear-spin-based spintronics. DNP based on optical pumping of point defects has been demonstrated by using the electron spin of nitrogen-vacancy (NV) center in diamond, and more recently, by using divacancy and related defect spins in hexagonal silicon carbide (SiC). Here, we describe a general model for these optical DNP processes that allows the effects of many microscopic processes to be integrated. Applying this theory, we gain a deeper insight into dynamic nuclear spin polarization and the physics of diamond and SiC defects. Our results are in good agreement with experimental observations and provide a detailed and unified understanding. In particular, our findings show that the defect electron spin coherence times and excited state lifetimes are crucial factors in the entire DNP process.

Analysis of the 48Ca neutron skin using a nonlocal dispersive-optical-model self-energy

NASA Astrophysics Data System (ADS)

Atkinson, Mack; Mahzoon, Hossein; Dickhoff, Willem; Charity, Robert

2017-09-01

A nonlocal dispersive-optical-model (DOM) analysis of the 40Ca and 48Ca nuclei has been implemented. The real and imaginary potentials are constrained by fitting to elastic-scattering data, total and reaction cross sections, energy level information, particle number, and the charge densities of 40Ca and 48Ca, respectively. The nonlocality of these potentials permits a proper dispersive self-energy which accurately describes both positive and negative energy observables. 48Ca is of particular interest because it is doubly magic and has a neutron skin due to the excess of neutrons. The DOM neutron skin radius is found to be rskin = 0.245 , which is larger than most previous calculations. The neutron skin is closely related to the symmetry energy which is a crucial part of the nuclear equation of state. The combined analysis of 40Ca and 48Ca energy densities provides a description of the density dependence of the symmetry energy which is compared with the 48Ca neutron skin. Results for 208Pb will also become available in the near future. NSF.

Electrically tunable dynamic nuclear spin polarization in GaAs quantum dots at zero magnetic field

NASA Astrophysics Data System (ADS)

Manca, M.; Wang, G.; Kuroda, T.; Shree, S.; Balocchi, A.; Renucci, P.; Marie, X.; Durnev, M. V.; Glazov, M. M.; Sakoda, K.; Mano, T.; Amand, T.; Urbaszek, B.

2018-04-01

In III-V semiconductor nano-structures, the electron and nuclear spin dynamics are strongly coupled. Both spin systems can be controlled optically. The nuclear spin dynamics are widely studied, but little is known about the initialization mechanisms. Here, we investigate optical pumping of carrier and nuclear spins in charge tunable GaAs dots grown on 111A substrates. We demonstrate dynamic nuclear polarization (DNP) at zero magnetic field in a single quantum dot for the positively charged exciton X+ state transition. We tune the DNP in both amplitude and sign by variation of an applied bias voltage Vg. Variation of ΔVg on the order of 100 mV changes the Overhauser splitting (nuclear spin polarization) from -30 μeV (-22%) to +10 μeV (+7%) although the X+ photoluminescence polarization does not change sign over this voltage range. This indicates that absorption in the structure and energy relaxation towards the X+ ground state might provide favourable scenarios for efficient electron-nuclear spin flip-flops, generating DNP during the first tens of ps of the X+ lifetime which is on the order of hundreds of ps. Voltage control of DNP is further confirmed in Hanle experiments.

Retinal single-layer analysis with optical coherence tomography shows inner retinal layer thinning in Huntington's disease as a potential biomarker.

PubMed

Gulmez Sevim, Duygu; Unlu, Metin; Gultekin, Murat; Karaca, Cagatay

2018-02-12

There have been ongoing clinical trials of therapeutic agents in Huntington's disease (HD) which requires development of reliable biomarkers of disease progression. There have been studies in the literature with conflicting results on the involvement of retina in HD, and up to date there is not a study evaluating the single retinal layers in HD. We aimed to evaluate the specific retinal changes in HD and their usability as potential disease progression markers. This cross-sectional study used spectral-domain optical coherence tomography with automatic segmentation to measure peripapillary retinal nerve fiber layer (pRNFL) thickness and the thickness and volume of retinal layers in foveal scans of 15 patients with HD and 15 age- and sex-matched controls. Genetic testing results, disease duration, HD disease burden scores and Unified HD Rating Scales motor scores were acquired for the patients. Temporal pRNFL, macular RNFL (mRNFL), ganglion cell layer (GCL), inner plexiform layer (IPL), inner nuclear layer and outer plexiform layer thicknesses and IPL, retinal pigment epithelium and outer macular volume were found lower in HD compared to controls, while outer nuclear layer and outer retinal layer thickness were increased (p < 0.05). We found significant correlations between inner retinal layer thicknesses, most significantly with mRNFL and GCL and disease progression markers. The outcomes of this study points out that retinal layers, most significantly mRNFL and GCL, are strongly correlated with the disease progression in HD and could serve as useful biomarkers for disease progression.

RETINAL DEEP CAPILLARY ISCHEMIA ASSOCIATED WITH AN OCCLUDED CONGENITAL RETINAL MACROVESSEL.

PubMed

Hasegawa, Taiji; Ogata, Nahoko

2017-01-01

To report the case of a patient with an occluded congenital retinal macrovessel accompanied by retinal deep capillary ischemia. A 38-year-old woman presented with a 2-day history of a paracentral scotoma of her right eye. Fundus photograph showed a dilated congenital retinal macrovessel with arteriovenous anastomosis, an intravascular white region indicating the thrombus at arteriovenous anastomotic region, and an area of retinal whitening temporal to the fovea. The spectral domain optical coherence tomography images through the area of retinal whitening showed a thickening and highly reflectivity at the level of the inner nuclear layer, which is likely due to the deep capillary ischemia. After 6 weeks, spectral domain optical coherence tomography images through the same area demonstrated a thinning and atrophy of only the inner nuclear layer, and the patient's paracentral scotoma persisted. Acute capillary hemodynamic changes caused deep capillary ischemia. The spectral domain optical coherence tomography showed a highly reflective lesion at the level of the inner nuclear layer in the acute phase.

Modelling Neutron-induced Reactions on 232–237U from 10 keV up to 30 MeV

DOE PAGES

Sin, M.; Capote, R.; Herman, M. W.; ...

2017-01-17

Comprehensive calculations of cross sections for neutron-induced reactions on 232–237U targets are performed in this paper in the 10 keV–30 MeV incident energy range with the code EMPIRE–3.2 Malta. The advanced modelling and consistent calculation scheme are aimed at improving our knowledge of the neutron scattering and emission cross sections, and to assess the consistency of available evaluated libraries for light uranium isotopes. The reaction model considers a dispersive optical potential (RIPL 2408) that couples from five (even targets) to nine (odd targets) levels of the ground-state rotational band, and a triple-humped fission barrier with absorption in the wells describedmore » within the optical model for fission. A modified Lorentzian model (MLO) of the radiative strength function and Enhanced Generalized Superfluid Model nuclear level densities are used in Hauser-Feschbach calculations of the compound-nuclear decay that include width fluctuation corrections. The starting values for the model parameters are retrieved from RIPL. Excellent agreement with available experimental data for neutron emission and fission is achieved, giving confidence that the quantities for which there is no experimental information are also accurately predicted. Finally, deficiencies in existing evaluated libraries are highlighted.« less

Effects of NN potentials on p Nuclides in the A ˜100-120 region

NASA Astrophysics Data System (ADS)

Lahiri, C.; Biswal, S. K.; Patra, S. K.

2016-02-01

Microscopic optical potentials for low-energy proton reactions have been obtained by folding density dependent M3Y (DDM3Y) interaction derived from nuclear matter calculation with densities from mean field approach to study astrophysically important proton rich nuclei in mass 100-120 region. We compare S factors for low-energy (p,γ) reactions with available experimental data and further calculate astrophysical reaction rates for (p,γ) and (p,n) reactions. Again, we choose some nonlinear R3Y (NR3Y) interactions from relativistic mean field (RMF) calculation and folded them with corresponding RMF densities to reproduce experimental S-factor values in this mass region. Finally, the effect of nonlinearity on our result is discussed.

Decoherence and fluctuation dynamics of the quantum dot nuclear spin bath probed by nuclear magnetic resonance

NASA Astrophysics Data System (ADS)

Chekhovich, Evgeny A.

2017-06-01

Dynamics of nuclear spin decoherence and nuclear spin flip-flops in self-assembled InGaAs/GaAs quantum dots are studied experimentally using optically detected nuclear magnetic resonance (NMR). Nuclear spin-echo decay times are found to be in the range 1-4 ms. This is a factor of ~3 longer than in strain-free GaAs/AlGaAs structures and is shown to result from strain-induced quadrupolar effects that suppress nuclear spin flip-flops. The correlation times of the flip-flops are examined using a novel frequency-comb NMR technique and are found to exceed 1 s, a factor of ~1000 longer than in strain-free structures. These findings complement recent studies of electron spin coherence and reveal the paradoxical dual role of the quadrupolar effects in self-assembled quantum dots: large increase of the nuclear spin bath coherence and at the same time significant reduction of the electron spin-qubit coherence. Approaches to increasing electron spin coherence are discussed. In particular the nanohole filled GaAs/AlGaAs quantum dots are an attractive option: while their optical quality matches the self-assembled dots the quadrupolar effects measured in NMR spectra are a factor of 1000 smaller.

All-optical control of long-lived nuclear spins in rare-earth doped nanoparticles.

PubMed

Serrano, D; Karlsson, J; Fossati, A; Ferrier, A; Goldner, P

2018-05-29

Nanoscale systems that coherently couple to light and possess spins offer key capabilities for quantum technologies. However, an outstanding challenge is to preserve properties, and especially optical and spin coherence lifetimes, at the nanoscale. Here, we report optically controlled nuclear spins with long coherence lifetimes (T 2 ) in rare-earth-doped nanoparticles. We detect spins echoes and measure a spin coherence lifetime of 2.9 ± 0.3 ms at 5 K under an external magnetic field of 9 mT, a T 2 value comparable to those obtained in bulk rare-earth crystals. Moreover, we achieve spin T 2 extension using all-optical spin dynamical decoupling and observe high fidelity between excitation and echo phases. Rare-earth-doped nanoparticles are thus the only nano-material in which optically controlled spins with millisecond coherence lifetimes have been reported. These results open the way to providing quantum light-atom-spin interfaces with long storage time within hybrid architectures.

Precise determination of lattice phase shifts and mixing angles

DOE PAGES

Lu, Bing -Nan; Lähde, Timo A.; Lee, Dean; ...

2016-07-09

Here, we introduce a general and accurate method for determining lattice phase shifts and mixing angles, which is applicable to arbitrary, non-cubic lattices. Our method combines angular momentum projection, spherical wall boundaries and an adjustable auxiliary potential. This allows us to construct radial lattice wave functions and to determine phase shifts at arbitrary energies. For coupled partial waves, we use a complex-valued auxiliary potential that breaks time-reversal invariance. We benchmark our method using a system of two spin-1/2 particles interacting through a finite-range potential with a strong tensor component. We are able to extract phase shifts and mixing angles formore » all angular momenta and energies, with precision greater than that of extant methods. We discuss a wide range of applications from nuclear lattice simulations to optical lattice experiments.« less

Nuclear Science Symposium, 4th, and Nuclear Power Systems Symposium, 9th, San Francisco, Calif., October 19-21, 1977, Proceedings

NASA Technical Reports Server (NTRS)

1978-01-01

Consideration is given to the following types of high energy physics instrumentation: drift chambers, multiwire proportional chambers, calorimeters, optical detectors, ionization and scintillation detectors, solid state detectors, and electronic and digital subsystems. Attention is also paid to reactor instrumentation, nuclear medicine instrumentation, data acquisition systems for nuclear instrumentation, microprocessor applications in nuclear science, environmental instrumentation, control and instrumentation of nuclear power generating stations, and radiation monitoring. Papers are also presented on instrumentation for the High Energy Astronomy Observatory.

Theoretical study of NMR, infrared and Raman spectra on triple-decker phthalocyanines

NASA Astrophysics Data System (ADS)

Suzuki, Atsushi; Oku, Takeo

2016-02-01

Electronic structures and magnetic properties of multi-decker phthalocyanines were studied by theoretical calculation. Electronic structures, excited processes at multi-states, isotropic chemical shifts of 13C, 14N and 1H-nuclear magnetic resonance (NMR), principle V-tensor in electronic field gradient (EFG) tensor and asymmetry parameters (η), vibration mode in infrared (IR) and Raman spectra of triple-decker phthalocyanines were calculated by density functional theory (DFT) and time-dependent DFT using B3LYP as basis function. Electron density distribution was delocalized on the phthalocyanine rings with electron static potential. Considerable separation of chemical shifts in 13C, 14N and 1H-NMR was originated from nuclear spin interaction between nitrogen and carbon atoms, nuclear quadrupole interaction based on EFG and η of central metal under crystal field. Calculated optical absorption at multi-excited process was derived from overlapping π-orbital on the phthalocyanine rings. The vibration modes in IR and Raman spectra were based on in-plane deformation and stretching vibrations of metal-ligand coordination bond on the deformed structure.

Communication: Nuclear quadrupole moment-induced Cotton-Mouton effect in noble gas atoms

NASA Astrophysics Data System (ADS)

Fu, Li-juan; Rizzo, Antonio; Vaara, Juha

2013-11-01

New, high-sensitivity and high-resolution spectroscopic and imaging methods may be developed by exploiting nuclear magneto-optic effects. A first-principles electronic structure formulation of nuclear electric quadrupole moment-induced Cotton-Mouton effect (NQCME) is presented for closed-shell atoms. In NQCME, aligned quadrupole moments alter the index of refraction of the medium along with and perpendicular to the direction of nuclear alignment. The roles of basis-set convergence, electron correlation, and relativistic effects are investigated for three quadrupolar noble gas isotopes: 21Ne, 83Kr, and 131Xe. The magnitude of the resulting ellipticities is predicted to be 10-4-10-6 rad/(M cm) for fully spin-polarized nuclei. These should be detectable in the Voigt setup. Particularly interesting is the case of 131Xe, in which a high degree of spin polarization can be achieved via spin-exchange optical hyperpolarization.

Coherent manipulation of non-thermal spin order in optical nuclear polarization experiments

NASA Astrophysics Data System (ADS)

Buntkowsky, Gerd; Ivanov, Konstantin L.; Zimmermann, Herbert; Vieth, Hans-Martin

2017-03-01

Time resolved measurements of Optical Nuclear Polarization (ONP) have been performed on hyperpolarized triplet states in molecular crystals created by light excitation. Transfer of the initial electron polarization to nuclear spins has been studied in the presence of radiofrequency excitation; the experiments have been performed with different pulse sequences using different doped molecular systems. The experimental results clearly demonstrate the dominant role of coherent mechanisms of spin order transfer, which manifest themselves in well pronounced oscillations. These oscillations are of two types, precessions and nutations, having characteristic frequencies, which are the same for the different molecular systems and the pulse sequences applied. Hence, precessions and nutations constitute a general feature of polarization transfer in ONP experiments. In general, coherent manipulation of spin order transfer creates a powerful resource for improving the performance of the ONP method, which paves the way to strong signal enhancement in nuclear magnetic resonance.

Theory of time-resolved x-ray photoelectron diffraction from transient conformational molecules

NASA Astrophysics Data System (ADS)

Tsuru, Shota; Sako, Tokuei; Fujikawa, Takashi; Yagishita, Akira

2017-04-01

We formulate x-ray photoelectron diffraction (XPD) from molecules undergoing photochemical reactions induced by optical laser pulses, and then apply the formula to the simulation of time-dependent XPD profiles from both dissociating I2 molecules and bending C S2 molecules. The dependence of nuclear wave-packet motions on the intensity and shape of the optical laser pulses is examined. As a result, the XPD simulations based on such nuclear wave-packet calculations are observed to exhibit characteristic features, which are compared with the XPD profiles due to classical trajectories of nuclear motions. The present study provides a methodology toward creating "molecular movies" of ultrafast photochemical reactions by means of femtosecond XPD with x-ray free-electron lasers.

An automatic analyzer of solid state nuclear track detectors using an optic RAM as image sensor

NASA Astrophysics Data System (ADS)

Staderini, Enrico Maria; Castellano, Alfredo

1986-02-01

An optic RAM is a conventional digital random access read/write dynamic memory device featuring a quartz windowed package and memory cells regularly ordered on the chip. Such a device is used as an image sensor because each cell retains data stored in it for a time depending on the intensity of the light incident on the cell itself. The authors have developed a system which uses an optic RAM to acquire and digitize images from electrochemically etched CR39 solid state nuclear track detectors (SSNTD) in the track count rate up to 5000 cm -2. On the digital image so obtained, a microprocessor, with appropriate software, performs image analysis, filtering, tracks counting and evaluation.

Optical model potential analysis of n ¯ A and n A interactions

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

Lee, Teck-Ghee; Wong, Cheuk-Yin

In this study, we use a momentum-dependent optical model potential to analyze the annihilation cross sections of the antineutronmore » $$\\overline{n}$$ on C, Al, Fe, Cu, Ag, Sn, and Pb nuclei for projectile momenta p lab ≲ 500 MeV / c . We obtain a good description of annihilation cross section data of Barbina et al. [Nucl. Phys. A 612, 346 (1997)] and of Astrua et al. [Nucl. Phys. A 697, 209 (2002)] which exhibit an interesting dependence of the cross sections on p lab as well as on the target mass number A. We also obtain the neutron (n) nonelastic reaction cross sections for the same targets. Comparing the $nA$ reaction cross sections σ$$nA\\atop{rec}$$ to the $$\\overline{n}A$$ annihilation cross sections σ $$\\overline{n}A$$ ann, we find that σ $$\\overline{n}A$$ ann is significantly larger than σ$$nA\\atop{rec}$$, that is, theσ $$\\overline{n}A$$ ann / σ$$nA\\atop{rec}$$ cross section ratio lies between the values of about 1.5 to 4.0 in the momentum region where comparison is possible. The dependence of the $$\\overline{n}$$ annihilation cross section on the projectile charge is also examined in comparison with the antiproton $$\\overline{p}$$. Here we predict the $$\\overline{p}A$$ annihilation cross section on the simplest assumption that both $$\\overline{p}A$$ and $$\\overline{n}A$$ interactions have the same nuclear part of the optical potential but differ only in the electrostatic Coulomb interaction. Finally, deviation from a such simple model extrapolation in measurements will provide new information on the difference between $$\\overline{n}A$$ and $$\\overline{p}A$$ potentials.« less

Optical model potential analysis of n ¯A and n A interactions

NASA Astrophysics Data System (ADS)

Lee, Teck-Ghee; Wong, Cheuk-Yin

2018-05-01

We use a momentum-dependent optical model potential to analyze the annihilation cross sections of the antineutron n ¯ on C, Al, Fe, Cu, Ag, Sn, and Pb nuclei for projectile momenta plab ≲500 MeV /c . We obtain a good description of annihilation cross section data of Barbina et al. [Nucl. Phys. A 612, 346 (1997), 10.1016/S0375-9474(96)00331-4] and of Astrua et al. [Nucl. Phys. A 697, 209 (2002), 10.1016/S0375-9474(01)01252-0] which exhibit an interesting dependence of the cross sections on plab as well as on the target mass number A . We also obtain the neutron (n ) nonelastic reaction cross sections for the same targets. Comparing the n A reaction cross sections σrecn A to the n ¯A annihilation cross sections σannn ¯A, we find that σannn ¯A is significantly larger than σrecn A, that is, the σannn ¯A/σrecn A cross section ratio lies between the values of about 1.5 to 4.0 in the momentum region where comparison is possible. The dependence of the n ¯ annihilation cross section on the projectile charge is also examined in comparison with the antiproton p ¯. Here we predict the p ¯A annihilation cross section on the simplest assumption that both p ¯A and n ¯A interactions have the same nuclear part of the optical potential but differ only in the electrostatic Coulomb interaction. Deviation from a such simple model extrapolation in measurements will provide new information on the difference between n ¯A and p ¯A potentials.

Optical model potential analysis of n ¯ A and n A interactions

DOE PAGES

Lee, Teck-Ghee; Wong, Cheuk-Yin

2018-05-25

In this study, we use a momentum-dependent optical model potential to analyze the annihilation cross sections of the antineutronmore » $$\\overline{n}$$ on C, Al, Fe, Cu, Ag, Sn, and Pb nuclei for projectile momenta p lab ≲ 500 MeV / c . We obtain a good description of annihilation cross section data of Barbina et al. [Nucl. Phys. A 612, 346 (1997)] and of Astrua et al. [Nucl. Phys. A 697, 209 (2002)] which exhibit an interesting dependence of the cross sections on p lab as well as on the target mass number A. We also obtain the neutron (n) nonelastic reaction cross sections for the same targets. Comparing the $nA$ reaction cross sections σ$$nA\\atop{rec}$$ to the $$\\overline{n}A$$ annihilation cross sections σ $$\\overline{n}A$$ ann, we find that σ $$\\overline{n}A$$ ann is significantly larger than σ$$nA\\atop{rec}$$, that is, theσ $$\\overline{n}A$$ ann / σ$$nA\\atop{rec}$$ cross section ratio lies between the values of about 1.5 to 4.0 in the momentum region where comparison is possible. The dependence of the $$\\overline{n}$$ annihilation cross section on the projectile charge is also examined in comparison with the antiproton $$\\overline{p}$$. Here we predict the $$\\overline{p}A$$ annihilation cross section on the simplest assumption that both $$\\overline{p}A$$ and $$\\overline{n}A$$ interactions have the same nuclear part of the optical potential but differ only in the electrostatic Coulomb interaction. Finally, deviation from a such simple model extrapolation in measurements will provide new information on the difference between $$\\overline{n}A$$ and $$\\overline{p}A$$ potentials.« less

Progress towards measuring the Rydberg Constant Using Circular Rydberg Atoms in an Intensity-Modulated Optical Lattice

NASA Astrophysics Data System (ADS)

Ramos, Andira; Moore, Kaitlin; Raithel, Georg

2015-05-01

Recent significant disagreement with the previously established size of the proton demonstrates a need to reconsider the current value of the Rydberg constant, the effects of the nuclear charge distribution and QED in hydrogen-like atoms. An experiment is in progress to obtain a measurement of the Rydberg constant by studying circular Rydberg atoms, which exhibit very small QED shifts and electron wavefunctions which do not overlap with the nucleus. Cold Rydberg atoms are trapped using a ponderomotive potential. To drive the transitions, a novel type of spectroscopy is used which utilizes an optical-lattice field that is intensity-modulated at the frequencies of atomic transitions. The method is free of typical spectroscopic selection rules and has been shown to drive transitions up to fifth order. Combined with optical Rydberg-atom trapping, the method enables the measurement of narrow, sub-THz transitions between long-lived circular Rydberg levels. Energy shifts affecting this precision measurement will also be discussed. This work is suported by NSF, NIST and NASA grants.

Energetic radiation influence on temperature dependency of Brillouin frequency in optical fibers

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

Pheron, X.; Ouerdane, Y.; Delepine-Lesoille, S.

We present a post mortem study of the influence of energetic radiation on optical fiber Brillouin sensors, both Brillouin spectrum and its temperature dependency in two different fibers, a photosensitive optical fiber and a SMF28. The target application is nuclear wastes repository monitoring where optical fiber Brillouin sensors might be exposed to energetic radiation. UV exposure induced optical losses, Brillouin frequency shifts up to 28 MHz and even a variation of the temperature dependency. The photosensitive optical fiber resulted more sensitive than SMF28{sup TM}. (authors)

Analysis of corrections to the eikonal approximation

NASA Astrophysics Data System (ADS)

Hebborn, C.; Capel, P.

2017-11-01

Various corrections to the eikonal approximations are studied for two- and three-body nuclear collisions with the goal to extend the range of validity of this approximation to beam energies of 10 MeV/nucleon. Wallace's correction does not improve much the elastic-scattering cross sections obtained at the usual eikonal approximation. On the contrary, a semiclassical approximation that substitutes the impact parameter by a complex distance of closest approach computed with the projectile-target optical potential efficiently corrects the eikonal approximation. This opens the possibility to analyze data measured down to 10 MeV/nucleon within eikonal-like reaction models.

ELASTIC SCATTERING ANGULAR DISTRIBUTIONS AND TOTAL REACTION CROSS SECTIONS FOR THE INTERACTION OF 12.8 Mev DEUTERONS WITH Ni$sup 58$ AND Ni$sup 60$ NUCLEI

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

Budzanowski, A.; Grotowski, K.

1962-10-15

Recentiy optical model analysis has been applied to fit the experimental angular distribution data of the elastic scattering of deuterons by nuclei. In view of a considerable dependence of sigma /sub R/ on the shape of the real and imaginary part of the potential at the nuclear surface, it was thought worthwhile to measure both sigma /sub el/ ( theta ) and sigma /sub R/ for 12.8 Mev deuterons on targets of separated Ni/sup 58/ and Ni/sup 60/ isotopes. (W.D.M.)

Directing Nuclear Spin Flips in InAs Quantum Dots Using Detuned Optical Pulse Trains

DTIC Science & Technology

2009-04-24

Directing Nuclear Spin Flips in InAs Quantum Dots Using Detuned Optical Pulse Trains S . G. Carter,1 A. Shabaev,2 Sophia E. Economou,1 T. A. Kennedy,1...A. S . Bracker,1 and T. L. Reinecke1 1Naval Research Laboratory, Washington, D.C. 20375-5322, USA 2School of Computational Sciences, George Mason...trion spin states and the allowed transitions. Single (double) arrows are electron (hole) spins. PRL 102, 167403 (2009) P HY S I CA L R EV I EW LE T T ER

Use of cryostat sections from snap-frozen nervous tissue for combining stereological estimates with histological, cellular, or molecular analyses on adjacent sections.

PubMed

Schmitz, C; Dafotakis, M; Heinsen, H; Mugrauer, K; Niesel, A; Popken, G J; Stephan, M; Van de Berg, W D; von Hörsten, S; Korr, H

2000-10-01

Adequate tissue preparation is essential for both modern stereological and immunohistochemical investigations. However, combining these methodologies in a single study presents a number of obstacles pertaining to optimal histological preparation. Tissue shrinkage and loss of nuclei/nucleoli from the unprotected section surfaces of unembedded tissue used for immunohistochemistry may be problematic with regard to adequate stereological design. In this study, frozen cryostat sections from hippocampal and cerebellar regions of two rat strains and cerebellar and cerebral regions from a human brain were analyzed to determine the potential impact of these factors on estimates of neuron number obtained using the optical disector. Neuronal nuclei and nucleoli were clearly present in thin sections of snap-frozen rat (3 microm) and human (6 microm) tissue, indicating that neuronal nuclei/nucleoli are not unavoidably lost from unprotected section surfaces of unembedded tissue. In order to quantify the potential impact of any nuclear loss, optical fractionator estimates of rat hippocampal pyramidal cells in areas CA1-3 and cerebellar granule and Purkinje cells were made using minimal (1 microm) upper guard zones. Estimates did not differ from data reported previously in the literature. This data indicates that cryostat sections of snap-frozen nervous tissue may successfully be used for estimating total neuronal numbers using optical disectors.

Black Hole Demographics in and Nuclear Properties of Nearby Low Luminosity Radio Galaxies; Connections to Radio Activity?

NASA Technical Reports Server (NTRS)

Baum, S. A.; Kleijn, G. A. Verdoes; Xu, C.; ODea, C. P.; deZeeuw, P. T.

2004-01-01

We combine the results of an HST STIS and WFPC study of a complete sample of 21 nearby UGC low luminosity radio galaxies with the results of a radio VLA and VLBA study of the same sample. We examine the relationship between the stellar and gaseous properties of the galaxies on tens to hundreds of parsec scale with the properties of the radio jets on the same scale. From the VLA and VLBA data we constrain the physics of the outflowing radio plasma from the tens of parsecs to hundreds of kiloparsec scales. From the WFPC2 H alpha and dust images and the STIS kinematics of the near nuclear gas we obtain constraints on the orientation of near nuclear disks of gas and measures of the nuclear stellar, continuum point source, and line emission fluxes. Under the statistically supported assumption that the radio jet issues perpendicular to the disk, we use the orientation of the optical (large scale accretion?) disks to constrain the three-dimensional orientation of the radio ejection. From HST/STIS spectroscopy of the near-nuclear emission line gas we obtain measures/limits on the black hole masses. We examine correlations between the VLBA and VLA-scale radio emission, the nuclear line emission, and the nuclear optical and radio continuum emission. Though our sample is relatively small, it is uniquely well defined, spans a narrow range in redshift and we have a consistent set of high resolution data with which to carefully examine these relationships. We use the combined radio and optical data to: 1) Constrain the orientation, physics, and bulk outflow speed of the radio plasma; 2) Put limits on the mass accretion rate and study the relationship between black hole mass, radio luminosity, and near nuclear gaseous content; 3) Provide insight into the relationship between BL Lac objects and low luminosity radio galaxies.

Nuclear Spin Locking and Extended Two-Electron Spin Decoherence Time in an InAs Quantum Dot Molecule

NASA Astrophysics Data System (ADS)

Chow, Colin; Ross, Aaron; Steel, Duncan; Sham, L. J.; Bracker, Allan; Gammon, Daniel

2015-03-01

The spin eigenstates for two electrons confined in a self-assembled InAs quantum dot molecule (QDM) consist of the spin singlet state, S, with J = 0 and the triplet states T-, T0 and T+, with J = 1. When a transverse magnetic field (Voigt geometry) is applied, the two-electron system can be initialized to the different states with appropriate laser excitation. Under the excitation of a weak probe laser, non-Lorentzian lineshapes are obtained when the system is initialized to either T- or T+, where T- results in a ``resonance locking'' lineshape while T+ gives a ``resonance avoiding '' lineshape: two different manifestations of hysteresis showing the importance of memory in the system. These observations signify dynamic nuclear spin polarization (DNSP) arising from a feedback mechanism involving hyperfine interaction between lattice nuclei and delocalized electron spins, and Overhauser shift due to nuclear spin polarization. Using pump configurations that generate coherent population trapping, the isolation of the electron spin from the optical excitation shows the stabilization of the nuclear spin ensemble. The dark-state lineshape measures the lengthened electron spin decoherence time, from 1 ns to 1 μs. Our detailed spectra highlight the potential of QDM for realizing a two-qubit gate. This work is supported by NSF, ARO, AFOSR, DARPA, and ONR.

Evaluation of the automatic optical authentication technologies for control systems of objects

NASA Astrophysics Data System (ADS)

Averkin, Vladimir V.; Volegov, Peter L.; Podgornov, Vladimir A.

2000-03-01

The report considers the evaluation of the automatic optical authentication technologies for the automated integrated system of physical protection, control and accounting of nuclear materials at RFNC-VNIITF, and for providing of the nuclear materials nonproliferation regime. The report presents the nuclear object authentication objectives and strategies, the methodology of the automatic optical authentication and results of the development of pattern recognition techniques carried out under the ISTC project #772 with the purpose of identification of unique features of surface structure of a controlled object and effects of its random treatment. The current decision of following functional control tasks is described in the report: confirmation of the item authenticity (proof of the absence of its substitution by an item of similar shape), control over unforeseen change of item state, control over unauthorized access to the item. The most important distinctive feature of all techniques is not comprehensive description of some properties of controlled item, but unique identification of item using minimum necessary set of parameters, properly comprising identification attribute of the item. The main emphasis in the technical approach is made on the development of rather simple technological methods for the first time intended for use in the systems of physical protection, control and accounting of nuclear materials. The developed authentication devices and system are described.

Non-Nuclear Testing of Fission Technologies at NASA MSFC

NASA Technical Reports Server (NTRS)

Houts, Robert G.; Pearson, J. Boise; Aschenbrenner, Kenneth C.; Bradley, David E.; Dickens, Ricky E.; Emrich, William J.; Garber, Anne E.; Godfroy, Thomas J.; Harper, Roger T.; Martin, Jim J.;

Neutral hydrogen in elliptical galaxies with nuclear radio sources and optical emission lines

NASA Technical Reports Server (NTRS)

Dressel, L. L.; Bania, T. M.; Oconnell, R. W.

1982-01-01

An H I detection survey of eleven elliptical galaxies with powerful nuclear radio sources was conducted, using the 305 m antenna of Arecibo Observatory, to test the hypothesis that large H I mass is conductive to the formation of nuclear radio sources in elliptical galaxies. The H I was detected in emission in UGC 09114 and was possibly detected in absorption in UGC 06671. Observations of the remaining galaxies were not sensitive enough to support or refute the hypothesis. Data was combined from other H I surveys and spectroscopic surveys to search for correlations of H I mass with other galactic properties and environmental conditions. Strong correlations of (O II) lambda 3727 emission with H I content and with nuclear radio power were found. The latter two properties may simply indicate, respectively, whether a significant amount of gas is available to be ionized and whether energy is provided by nuclear activity for ionization. No dependence of H I content on optical luminosity or on degree of isolation from other galaxies was found.

2nd-order optical model of the isotopic dependence of heavy ion absorption cross sections for radiation transport studies

NASA Astrophysics Data System (ADS)

Cucinotta, Francis A.; Yan, Congchong; Saganti, Premkumar B.

2018-01-01

Heavy ion absorption cross sections play an important role in radiation transport codes used in risk assessment and for shielding studies of galactic cosmic ray (GCR) exposures. Due to the GCR primary nuclei composition and nuclear fragmentation leading to secondary nuclei heavy ions of charge number, Z with 3 ≤ Z ≥ 28 and mass numbers, A with 6 ≤ A ≥ 60 representing about 190 isotopes occur in GCR transport calculations. In this report we describe methods for developing a data-base of isotopic dependent heavy ion absorption cross sections for interactions. Calculations of a 2nd-order optical model solution to coupled-channel solutions to the Eikonal form of the nucleus-nucleus scattering amplitude are compared to 1st-order optical model solutions. The 2nd-order model takes into account two-body correlations in the projectile and target ground-states, which are ignored in the 1st-order optical model. Parameter free predictions are described using one-body and two-body ground state form factors for the isotopes considered and the free nucleon-nucleon scattering amplitude. Root mean square (RMS) matter radii for protons and neutrons are taken from electron and muon scattering data and nuclear structure models. We report on extensive comparisons to experimental data for energy-dependent absorption cross sections for over 100 isotopes of elements from Li to Fe interacting with carbon and aluminum targets. Agreement between model and experiments are generally within 10% for the 1st-order optical model and improved to less than 5% in the 2nd-order optical model in the majority of comparisons. Overall the 2nd-order optical model leads to a reduction in absorption compared to the 1st-order optical model for heavy ion interactions, which influences estimates of nuclear matter radii.

4Pi microscopy of the nuclear pore complex.

PubMed

Kahms, Martin; Hüve, Jana; Peters, Reiner

2015-01-01

4Pi microscopy is a far-field fluorescence microscopy technique, in which the wave fronts of two opposing illuminating beams are adjusted to constructively interfere in a common focus. This yields a diffraction pattern in the direction of the optical axis, which essentially consists of a main focal spot accompanied by two smaller side lobes. At optimal conditions, the main peak of this so-called point spread function has a full width at half maximum: fixed phrase of 100 nm in the direction of the optical axis, and thus is 6-7-fold smaller than that of a confocal microscope. In this chapter, we describe the basic features of 4Pi microscopy and its application to cell biology using the example of the nuclear pore complex, a large protein assembly spanning the nuclear envelope.

Optical spectroscopies diagnose cancer

NASA Astrophysics Data System (ADS)

Alfano, Robert R.; Das, Bidyut B.; Glassman, Wenling S.; Pradhan, Asima; Tang, Gui C.

1992-02-01

Today's medical professional is looking beyond the conventional procedures of X-rays, nuclear radiation, magnetic resonance, chemical analysis, and ultrasound to diagnose diseases ranging from cancer to heart ailments. In view of the possible dangerous side effects of X-rays and nuclear radiation, a need exists for novel techniques in disease detection that can either eliminate or reduce their use in examinations. For more than half a century, fluorescence, absorption, and light scattering spectroscopies have been widely used as probes to acquire fundamental knowledge about various physical, chemical, and biological processes. Light may offer alternatives to X-rays and nuclear approaches, and in some cases is non-invasive. Optical spectroscopy and laser technology may offer techniques for the detection and characterization of physical and chemical changes that occur in diseased tissue on a microscopic level.

Biomedical nuclear and X-ray imager using high-energy grazing incidence mirrors

DOEpatents

Ziock, Klaus-Peter; Craig, William W.; Hasegawa, Bruce; Pivovaroff, Michael J.

2005-09-27

Imaging of radiation sources located in a subject is explored for medical applications. The approach involves using grazing-incidence optics to form images of the location of radiopharmaceuticals administered to a subject. The optics are "true focusing" optics, meaning that they project a real and inverted image of the radiation source onto a detector possessing spatial and energy resolution.

Laser-Induced Fluorescence Measurements for Optical Single Atom Detection for Nuclear Astrophysics

NASA Astrophysics Data System (ADS)

Parzuchowski, Kristen; Singh, Jaideep; Wenzl, Jennifer; Frisbie, Dustin; Johnson, Maegan

2016-09-01

We propose a new highly selective detector to measure rare nuclear reactions relevant for nuclear astrophysics. Our primary interest is the 22Ne(α , n) 25Mg reaction, which is a primary source of neutrons for the s-process. Our proposed detector, in conjunction with a recoil separator, captures the recoil products resulting from the reaction in a cryogenically frozen thin film of solid neon. The fluorescence spectra of the captured atoms is shifted from the absorption spectra by hundreds of nanometers. This allows for the optical detection of individual fluorescence photons against a background of intense excitation light. We will describe our initial studies of laser-induced fluorescence of Yb and Mg in solid Ne. Neon is an attractive medium because it is optically transparent and provides efficient, pure, stable, & chemically inert confinement for a wide variety of atomic and molecular species. Yb is used as a test atom because of its similar atomic structure to Mg and much brighter fluorescence signal. This work is supported by funds from Michigan State University.

Microscopic modeling of direct pre-equilibrium emission from neutron induced reactions on even and odd actinides

NASA Astrophysics Data System (ADS)

Dupuis, M.; Hilaire, S.; Péru, S.; Bauge, E.; Kerveno, M.; Dessagne, P.; Henning, G.

2017-09-01

Direct inelastic scattering to discrete excitations and pre-equilibrium emission are described within a microscopic model. Nuclear structure information are obtained in the (Quasi) Random Phase Approximation ((Q)RPA) framework implemented with the Gogny force. The relevant optical and transition potentials are build considering the JLM folding model. Various successful applications are shown for (n,n), (n,n'), (n,xn) and (n,xnγ) reactions for spherical and axially deformed even-even or odd targets. The rearrangement corrections to transition potentials and the contribution of unnatural parity excitations to pre-equilibrium emission are discussed. Our model predictions for (n,n'γ) reactions, for intra- and inter-band transitions in 238U, and for the 239Pu(n,2n) cross section are analyzed.

In-medium properties of mesons

NASA Astrophysics Data System (ADS)

Metag, Volker; Nanova, Mariana; Brinkmann, Kai-Thomas

2017-01-01

In the project B.4, the modification of meson properties (mass, width) in a nuclear medium has been studied in photoproduction of mesons off nuclear targets. This work has been motivated by theoretical expectations of in-medium modifications of hadrons based on the conjecture of a partial restoration of chiral symmetry in a strongly interacting medium. It has been shown that these in-medium changes can be discussed in a compact form in terms of an optical potential describing the meson-nucleus interaction. Experimental approaches to determine the real and imaginary part of the meson-nucleus potential have been developed. The experiments have been performed with the Crystal Barrel/TAPS detector at the electron accelerator ELSA (Bonn) and the Crystal Ball/TAPS detector at MAMI (Mainz). Measuring the excitation function and momentum distribution for photo production of ω and η' mesons, the real parts of the ω and η'-nucleus potential, given by the in-medium mass shift, have been determined. For the η' meson a lowering of the mass at normal nuclear matter density by -(39±7(stat)±15(syst)) MeV is observed, while for the ω meson a slightly smaller mass shift is found, however, with much larger uncertainties, not excluding a zero mass shift. The imaginary part of the potentials has been extracted from the measurement of the transparency ratio which compares the meson production cross section per nucleon within a nucleus to the production cross section off the free proton. For the η' meson the imaginary part of the potential is found to be smaller than the real part. In case of the ω meson the opposite is observed. This makes the η' meson a good candidate for the search for meson-nucleus bound states while no resolved ω mesic states can be expected. The results are compared with theoretical predictions. An outlook on future experiments is given.

Solid state laser media driven by remote nuclear powered fluorescence

DOEpatents

Prelas, Mark A.

1992-01-01

An apparatus is provided for driving a solid state laser by a nuclear powered fluorescence source which is located remote from the fluorescence source. A nuclear reaction produced in a reaction chamber generates fluorescence or photons. The photons are collected from the chamber into a waveguide, such as a fiber optic waveguide. The waveguide transports the photons to the remote laser for exciting the laser.

Optics in engineering measurement; Proceedings of the Meeting, Cannes, France, December 3-6, 1985

NASA Technical Reports Server (NTRS)

Fagan, William F. (Editor)

1986-01-01

The present conference on optical measurement systems considers topics in the fields of holographic interferometry, speckle techniques, moire fringe and grating methods, optical surface gaging, laser- and fiber-optics-based measurement systems, and optics for engineering data evaluation. Specific attention is given to holographic NDE for aerospace composites, holographic interferometry of rotating components, new developments in computer-aided holography, electronic speckle pattern interferometry, mass transfer measurements using projected fringes, nuclear reactor photogrammetric inspection, a laser Doppler vibrometer, and optoelectronic measurements of the yaw angle of projectiles.

Development of an Integrated Raman and Turbidity Fiber Optic Sensor for the In-Situ Analysis of High Level Nuclear Waste

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

Gasbarro, Christina; Bello, Job M.; Bryan, Samuel A.

2013-02-24

Stored nuclear waste must be retrieved from storage, treated, separated into low- and high-level waste streams, and finally put into a disposal form that effectively encapsulates the waste and isolates it from the environment for a long period of time. Before waste retrieval can be done, waste composition needs to be characterized so that proper safety precautions can be implemented during the retrieval process. In addition, there is a need for active monitoring of the dynamic chemistry of the waste during storage since the waste composition can become highly corrosive. This work describes the development of a novel, integrated fibermore » optic Raman and light scattering probe for in situ use in nuclear waste solutions. The dual Raman and turbidity sensor provides simultaneous chemical identification of nuclear waste as well as information concerning the suspended particles in the waste using a common laser excitation source.« less

Development of an Integrated Raman and Turbidity Fiber Optic Sensor for the In-Situ Analysis of High Level Nuclear Waste - 13532

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

Gasbarro, Christina; Bello, Job; Bryan, Samuel

2013-07-01

Stored nuclear waste must be retrieved from storage, treated, separated into low- and high-level waste streams, and finally put into a disposal form that effectively encapsulates the waste and isolates it from the environment for a long period of time. Before waste retrieval can be done, waste composition needs to be characterized so that proper safety precautions can be implemented during the retrieval process. In addition, there is a need for active monitoring of the dynamic chemistry of the waste during storage since the waste composition can become highly corrosive. This work describes the development of a novel, integrated fibermore » optic Raman and light scattering probe for in situ use in nuclear waste solutions. The dual Raman and turbidity sensor provides simultaneous chemical identification of nuclear waste as well as information concerning the suspended particles in the waste using a common laser excitation source. (authors)« less

Communication: Nuclear quadrupole moment-induced Cotton-Mouton effect in noble gas atoms

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

Fu, Li-juan; Vaara, Juha, E-mail: juha.vaara@iki.fi; Rizzo, Antonio

New, high-sensitivity and high-resolution spectroscopic and imaging methods may be developed by exploiting nuclear magneto-optic effects. A first-principles electronic structure formulation of nuclear electric quadrupole moment-induced Cotton-Mouton effect (NQCME) is presented for closed-shell atoms. In NQCME, aligned quadrupole moments alter the index of refraction of the medium along with and perpendicular to the direction of nuclear alignment. The roles of basis-set convergence, electron correlation, and relativistic effects are investigated for three quadrupolar noble gas isotopes: {sup 21}Ne, {sup 83}Kr, and {sup 131}Xe. The magnitude of the resulting ellipticities is predicted to be 10{sup −4}–10{sup −6} rad/(M cm) for fully spin-polarized nuclei.more » These should be detectable in the Voigt setup. Particularly interesting is the case of {sup 131}Xe, in which a high degree of spin polarization can be achieved via spin-exchange optical hyperpolarization.« less

Protecting a Diamond Quantum Memory by Charge State Control.

PubMed

Pfender, Matthias; Aslam, Nabeel; Simon, Patrick; Antonov, Denis; Thiering, Gergő; Burk, Sina; Fávaro de Oliveira, Felipe; Denisenko, Andrej; Fedder, Helmut; Meijer, Jan; Garrido, Jose A; Gali, Adam; Teraji, Tokuyuki; Isoya, Junichi; Doherty, Marcus William; Alkauskas, Audrius; Gallo, Alejandro; Grüneis, Andreas; Neumann, Philipp; Wrachtrup, Jörg

2017-10-11

In recent years, solid-state spin systems have emerged as promising candidates for quantum information processing. Prominent examples are the nitrogen-vacancy (NV) center in diamond, phosphorus dopants in silicon (Si:P), rare-earth ions in solids, and V Si -centers in silicon-carbide. The Si:P system has demonstrated that its nuclear spins can yield exceedingly long spin coherence times by eliminating the electron spin of the dopant. For NV centers, however, a proper charge state for storage of nuclear spin qubit coherence has not been identified yet. Here, we identify and characterize the positively charged NV center as an electron-spin-less and optically inactive state by utilizing the nuclear spin qubit as a probe. We control the electronic charge and spin utilizing nanometer scale gate electrodes. We achieve a lengthening of the nuclear spin coherence times by a factor of 4. Surprisingly, the new charge state allows switching of the optical response of single nodes facilitating full individual addressability.

Non-Nuclear Testing of Space Nuclear Systems at NASA MSFC

NASA Technical Reports Server (NTRS)

Houts, Michael G.; Pearson, Boise J.; Aschenbrenner, Kenneth C.; Bradley, David E.; Dickens, Ricky; Emrich, William J.; Garber, Anne; Godfroy, Thomas J.; Harper, Roger T.; Martin, Jim J.;

Electron and Nuclear Spin Interactions in the Optical Spectra of Single GaAs Quantum Dots

DTIC Science & Technology

2001-05-28

VOLUME 86, NUMBER 22 P H Y S I C A L R E V I E W L E T T E R S 28 MAY 2001 5 Electron and Nuclear Spin Interactions in the Optical Spectra of Single...GaAs Quantum Dots D. Gammon, Al. L. Efros, T. A. Kennedy, M. Rosen, D. S . Katzer, and D. Park Naval Research Laboratory, Washington, D.C. 20375 S . W...Brown NIST, Gaithersburg, Maryland V. L. Korenev and I. A. Merkulov A. F. Ioffe Institute, St. Petersburg, Russia (Received 18 December 2000) Fine and

Development of automated optical verification technologies for control systems

NASA Astrophysics Data System (ADS)

Volegov, Peter L.; Podgornov, Vladimir A.

1999-08-01

The report considers optical techniques for automated verification of object's identity designed for control system of nuclear objects. There are presented results of experimental researches and results of development of pattern recognition techniques carried out under the ISTC project number 772 with the purpose of identification of unique feature of surface structure of a controlled object and effects of its random treatment. Possibilities of industrial introduction of the developed technologies in frames of USA and Russia laboratories' lab-to-lab cooperation, including development of up-to-date systems for nuclear material control and accounting are examined.

Spin accumulation in thin Cs salts on contact with optically polarized Cs vapor

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

Ishikawa, Kiyoshi

2011-09-15

The spin angular momentum accumulates in the Cs nuclei of salt on contact with optically pumped Cs vapor. The spin polarization in stable chloride as well as dissociative hydride indicates that nuclear dipole interaction works in spin transferring with a lesser role of atom exchange. In the solid film, not only the spin buildup but also the decay of enhanced polarization is faster than the thermal recovery rate for the bulk salt. Eliminating the signal of thick salt, we find that the nuclear spin polarization in the chloride film reaches over 100 times the thermal equilibrium.

Effect of absorbing impurities on the accuracy of the optical method for the detection of the iodine-containing substances resulting from the processing of waste nuclear fuel

NASA Astrophysics Data System (ADS)

Kireev, S. V.; Simanovsky, I. G.; Shnyrev, S. L.

2010-12-01

The study is aimed at an increase in the accuracy of the optical method for the detection of the iodine-containing substances in technological liquids resulting form the processing of the waste nuclear fuel. It is demonstrated that the accuracy can be increased owing to the measurements at various combinations of wavelengths depending on the concentrations of impurities that are contained in the sample under study and absorb in the spectral range used for the detection of the iodine-containing substances.

Microcystic macular oedema in optic neuropathy: case series and literature review.

PubMed

Kessel, Line; Hamann, Steffen; Wegener, Marianne; Tong, Jessica; Fraser, Clare L

2018-05-25

Cavitations in the inner nuclear layer associated with severe optic atrophy and loss of retinal ganglion cells have clinically been termed microcystic macular oedema (MME). We describe a case series of MME in patients of all ages but predominantly younger patients with a wide range of optic atrophies ranging from acute onset optic disc drusen associated ischemic optic neuropathy to slowly progressive disease as glaucoma. There were no physical distinctions between MME in different causes of optic atrophy suggesting a common causative mechanism. We reviewed the literature on MME and it appears that MME is associated with more severe visual loss, and is more common in hereditary optic neuropathies and neuro-myelitis optica spectrum disease rather than in patients with optic atrophy secondary to multiple sclerosis and glaucoma. Three main causative mechanisms have been proposed, including increased vitreal traction on the macular as the ganglion cells are lost. Others have suggested that trans-synaptic loss of cells in the inner nuclear layer causes formation of empty spaces or cavities. Finally, some have hypothesized a disturbance in the fluid homeostasis of the inner retina as Müller cells are lost or their function is impaired. There are no known treatments of MME. In conclusion, MME seems to be a marker of severe optic nerve atrophy irrespective of the underlying cause. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Eddy current proximity measurement of perpendicular tubes from within pressure tubes in CANDU nuclear reactors

NASA Astrophysics Data System (ADS)

Bennett, P. F. D.; Underhill, P. R.; Morelli, J.; Krause, T. W.

2018-04-01

Fuel channels in CANDU® (CANada Deuterium Uranium) nuclear reactors consist of two non-concentric tubes; an inner pressure tube (PT) and a larger diameter calandria tube (CT). Up to 400 horizontally mounted fuel channels are contained within a calandria vessel, which also holds the heavy water moderator. Certain fuel channels pass perpendicularly over horizontally oriented tubes (nozzles) that are part of the reactor's liquid injection shutdown system (LISS). Due to sag, these fuel channels are at risk of coming into contact with the LISS nozzles. In the event of contact between the LISS nozzle and CT, flow-induced vibrations from within the moderator could lead to fretting and deformation of the CT. LISS nozzle proximity to CTs is currently measured optically from within the calandria vessel, but from outside the fuel channels. Measurement by an independent means would provide confidence in optical results and supplement cases where optical observations are not possible. Separation of PT and CT, known as gap, is monitored from within the PT using a transmit-receive eddy current probe. Investigation of the eddy current based gap probe as a tool to also measure proximity of LISS nozzles was carried out experimentally in this work. Eddy current response as a function of LISS-PT proximity was recorded. When PT-CT gap, PT wall thickness, PT resistivity and probe lift-off variations were not present this dependence could be used to determine the LISS-PT proximity. This method has the potential to provide LISS-CT proximity using existing gap measurement data. Obtaining LISS nozzle proximity at multiple inspection intervals could be used to provide an estimate of the time to LISS-CT contact, and thereby provide a means of optimizing maintenance schedules.

Quantitative in vivo cell-surface receptor imaging in oncology: kinetic modeling & paired-agent principles from nuclear medicine and optical imaging

PubMed Central

Tichauer, Kenneth M.; Wang, Yu; Pogue, Brian W.; Liu, Jonathan T. C.

2015-01-01

The development of methods to accurately quantify cell-surface receptors in living tissues would have a seminal impact in oncology. For example, accurate measures of receptor density in vivo could enhance early detection or surgical resection of tumors via protein-based contrast, allowing removal of cancer with high phenotype specificity. Alternatively, accurate receptor expression estimation could be used as a biomarker to guide patient-specific clinical oncology targeting of the same molecular pathway. Unfortunately, conventional molecular contrast-based imaging approaches are not well adapted to accurately estimating the nanomolar-level cell-surface receptor concentrations in tumors, as most images are dominated by nonspecific sources of contrast such as high vascular permeability and lymphatic inhibition. This article reviews approaches for overcoming these limitations based upon tracer kinetic modeling and the use of emerging protocols to estimate binding potential and the related receptor concentration. Methods such as using single time point imaging or a reference-tissue approach tend to have low accuracy in tumors, whereas paired-agent methods or advanced kinetic analyses are more promising to eliminate the dominance of interstitial space in the signals. Nuclear medicine and optical molecular imaging are the primary modalities used, as they have the nanomolar level sensitivity needed to quantify cell-surface receptor concentrations present in tissue, although each likely has a different clinical niche. PMID:26134619

Exome Array Analysis of Nuclear Lens Opacity.

PubMed

Loomis, Stephanie J; Klein, Alison P; Lee, Kristine E; Chen, Fei; Bomotti, Samantha; Truitt, Barbara; Iyengar, Sudha K; Klein, Ronald; Klein, Barbara E K; Duggal, Priya

2018-06-01

Nuclear cataract is the most common subtype of age-related cataract, the leading cause of blindness worldwide. It results from advanced nuclear sclerosis, or opacity in the center of the optic lens, and is affected by both genetic and environmental risk factors, including smoking. We sought to understand the genetic factors associated with nuclear sclerosis through interrogation of rare and low frequency coding variants using exome array data. We analyzed Illumina Human Exome Array data for 1,488 participants of European ancestry in the Beaver Dam Eye Study who were without cataract surgery for association with nuclear sclerosis grade, controlling for age and sex. We performed single-variant regression analysis for 32,138 variants with minor allele frequency (MAF) ≥0.003. In addition, gene-based analysis of 11,844 genes containing at least two variants with MAF < 0.05 was performed using a gene-based unified burden and non-burden sequence kernel association test (SKAT-O). Additionally, both single-variant and gene-based analyses were analyzed stratified by smoking status. No single-variant test was statistically significant after Bonferroni correction (p < 1.6 × 10 -6 ; top single nucleotide polymorphism (SNP): rs144458991, p = 2.83 × 10 -5 ). Gene-based tests were suggestively associated with the gene RNF149 overall (p = 8.29 × 10 -6 ) and among never smokers (N = 790, p = 2.67 × 10 -6 ). This study did not find a significant genetic association with nuclear sclerosis, the possible association with the RNF149 gene highlights a potential candidate gene for future studies that aim to understand the genetic architecture of nuclear sclerosis.

Observational artifacts of Nuclear Spectroscopic Telescope Array: ghost rays and stray light

NASA Astrophysics Data System (ADS)

Madsen, Kristin K.; Christensen, Finn E.; Craig, William W.; Forster, Karl W.; Grefenstette, Brian W.; Harrison, Fiona A.; Miyasaka, Hiromasa; Rana, Vikram

2017-10-01

The Nuclear Spectroscopic Telescope Array (NuSTAR) launched in June 2012, flies two conical approximation Wolter-I mirrors at the end of a 10.15-m mast. The optics are coated with multilayers of Pt/C and W/Si that operate from 3 to 80 keV. Since the optical path is not shrouded, aperture stops are used to limit the field of view (FoV) from background and sources outside the FoV. However, there is still a sliver of sky (˜1.0 deg to 4.0 deg) where photons may bypass the optics altogether and fall directly on the detector array. We term these photons stray light. Additionally, there are also photons that do not undergo the focused double reflections in the optics, and we term these ghost rays. We present detailed analysis and characterization of these two components and discuss how they impact observations. Finally, we discuss how they could have been prevented and should be in future observatories.

Ultraluminous infrared galaxies

NASA Technical Reports Server (NTRS)

Sanders, D. B.; Soifer, B. T.; Neugebauer, G.; Scoville, N. Z.; Madore, B. F.; Danielson, G. E.; Elias, J. H.; Matthews, K.; Persson, C. J.; Persson, S. E.

1987-01-01

The IRAS survey of the local universe has revealed the existence of a class of ultraluminous infrared galaxies with L(8 to 1000 micrometer) greater than 10 to the 12th L sub 0 that are slightly more numerous, and as luminous as optically selected quasars at similar redshift. Optical CCD images of these infrared galaxies show that nearly all are advanced mergers. Millimeter wave CO observations indicate that these interacting systems are extremely rich in molecular gas with total H2 masses 1 to 3 x 10 to the 10th power M sub 0. Nearly all of the ultraluminous infrared galaxies show some evidence in their optical spectra for nonthermal nuclear activity. It is proposed that their infrared luminosity is powered by an embedded active nucleus and a nuclear starburst both of which are fueled by the tremendous reservoir of molecular gas. Once these merger nuclei shed their obscuring dust, allowing the AGN to visually dominate the decaying starburst, they become the optically selected quasars.

Impact of (α, n) reactions on weak r-process in neutrino-driven winds

NASA Astrophysics Data System (ADS)

Bliss, J.; Arcones, A.; Montes, F.; Pereira, J.

2017-05-01

After a successful core-collapse supernova, a neutrino-driven wind develops where it is possible to synthesize lighter heavy elements (30 < Z < 45). In the early galaxy, the origin of these elements is associated with the r-process and to an additional process. Here we assume that the additional process corresponds to the weak r-process (sometimes referred to as alpha-process) taking place in neutrino-driven winds. Based on a trajectory obtained from hydrodynamical simulations we study the astrophysics and nuclear physics uncertainties of a weak r-process with our main focus on the (α, n) reactions. These reactions are critical to redistribute the matter and allow it to move from light to heavy elements after nuclear statistical equilibrium freezes out. In this first sensitivity study, we vary all (α, n) reactions by given constant factors which are justified based on the uncertainties of the statistical model and its nuclear physics input, mainly alpha optical potentials for weak r-process conditions. Our results show that (α, n) rate uncertainties are indeed crucial to predict abundances. Therefore, further studies will follow to identify individual critical reactions. Since the nucleosynthesis path is close to stability, these reactions can be measured in the near future. Since much of the other nuclear data for the weak r-process are known, the reduction in nuclear physics uncertainties provided by these experiments will allow astronomical observations to directly constrain the astronomical conditions in the wind.

Reduction of speckle noise from optical coherence tomography images using multi-frame weighted nuclear norm minimization method

NASA Astrophysics Data System (ADS)

Thapa, Damber; Raahemifar, Kaamran; Lakshminarayanan, Vasudevan

2015-12-01

In this paper, we propose a speckle noise reduction method for spectral-domain optical coherence tomography (SD-OCT) images called multi-frame weighted nuclear norm minimization (MWNNM). This method is a direct extension of weighted nuclear norm minimization (WNNM) in the multi-frame framework since an adequately denoised image could not be achieved with single-frame denoising methods. The MWNNM method exploits multiple B-scans collected from a small area of a SD-OCT volumetric image, and then denoises and averages them together to obtain a high signal-to-noise ratio B-scan. The results show that the image quality metrics obtained by denoising and averaging only five nearby B-scans with MWNNM method is considerably better than those of the average image obtained by registering and averaging 40 azimuthally repeated B-scans.

ESR Detection of optical dynamic nuclear polarization in GaAs/Al{sub x}Ga{sub 1-x}As quantum wells at unity filling factor in the quantum Hall effect

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

Vitkalov, Sergey A.; Bowers, C. Russell; Simmons, Jerry A.

2000-02-15

This paper presents a study of the enhancement of the Zeeman energy of two-dimensional (2D) conduction electrons near the {nu}=1 filling factor of the quantum Hall effect by optical dynamic nuclear polarization. The change in the Zeeman energy is determined from the Overhauser shift of the transport detected electron spin resonance in GaAs/Al{sub x}Ga{sub 1-x}As multiquantum wells. In a separate experiment the NMR signal enhancement factor is obtained by radio frequency detected nuclear magnetic resonance under similar conditions in the same sample. These measurements afford an estimation of the hyperfine coupling constant between the nuclei and 2D conduction electrons. (c)more » 2000 The American Physical Society.« less

High Neutron Fluence Survivability Testing of Advanced Fiber Bragg Grating Sensors

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

Fielder, Robert S.; Klemer, Daniel; Stinson-Bagby, Kelly L.

2004-02-04

The motivation for the reported research was to support NASA space nuclear power initiatives through the development of advanced fiber optic sensors for space-based nuclear power applications. The purpose of the high-neutron fluence testing was to demonstrate the survivability of fiber Bragg grating (FBG) sensors in a fission reactor environment. 520 FBGs were installed in the Ford reactor at the University of Michigan. The reactor was operated for 1012 effective full power hours resulting in a maximum neutron fluence of approximately 5x1019 n/cm2, and a maximum gamma dose of 2x103 MGy gamma. This work is significant in that, to themore » knowledge of the authors, the exposure levels obtained are approximately 1000 times higher than for any previously published experiment. Four different fiber compositions were evaluated. An 87% survival rate was observed for fiber Bragg gratings located at the fuel centerline. Optical Frequency Domain Reflectometry (OFDR), originally developed at the NASA Langley Research Center, can be used to interrogate several thousand low-reflectivity FBG strain and/or temperature sensors along a single optical fiber. A key advantage of the OFDR sensor technology for space nuclear power is the extremely low mass of the sensor, which consists of only a silica fiber 125{mu}m in diameter. The sensors produced using this technology will fill applications in nuclear power for current reactor plants, emerging Generation-IV reactors, and for space nuclear power. The reported research was conducted by Luna Innovations and was funded through a Small Business Innovative Research (SBIR) contract with the NASA Glenn Research Center.« less

High Neutron Fluence Survivability Testing of Advanced Fiber Bragg Grating Sensors

NASA Astrophysics Data System (ADS)

Fielder, Robert S.; Klemer, Daniel; Stinson-Bagby, Kelly L.

2004-02-01

The motivation for the reported research was to support NASA space nuclear power initiatives through the development of advanced fiber optic sensors for space-based nuclear power applications. The purpose of the high-neutron fluence testing was to demonstrate the survivability of fiber Bragg grating (FBG) sensors in a fission reactor environment. 520 FBGs were installed in the Ford reactor at the University of Michigan. The reactor was operated for 1012 effective full power hours resulting in a maximum neutron fluence of approximately 5×1019 n/cm2, and a maximum gamma dose of 2×103 MGy gamma. This work is significant in that, to the knowledge of the authors, the exposure levels obtained are approximately 1000 times higher than for any previously published experiment. Four different fiber compositions were evaluated. An 87% survival rate was observed for fiber Bragg gratings located at the fuel centerline. Optical Frequency Domain Reflectometry (OFDR), originally developed at the NASA Langley Research Center, can be used to interrogate several thousand low-reflectivity FBG strain and/or temperature sensors along a single optical fiber. A key advantage of the OFDR sensor technology for space nuclear power is the extremely low mass of the sensor, which consists of only a silica fiber 125μm in diameter. The sensors produced using this technology will fill applications in nuclear power for current reactor plants, emerging Generation-IV reactors, and for space nuclear power. The reported research was conducted by Luna Innovations and was funded through a Small Business Innovative Research (SBIR) contract with the NASA Glenn Research Center.

Cross-Section Measurements via the Activation Technique at the Cologne Clover Counting Setup

NASA Astrophysics Data System (ADS)

Heim, Felix; Mayer, Jan; Netterdon, Lars; Scholz, Philipp; Zilges, Andreas

The activation technique is a widely used method for the determination of cross-section values for charged-particle induced reactions at astrophysically relevant energies. Since network calculations of nucleosynthesis processes often depend on reaction rates calculated in the scope of the Hauser-Feshbach statistical model, these cross-sections can be used to improve the nuclear-physics input-parameters like optical-model potentials (OMP), γ-ray strength functions, and nuclear level densities. In order to extend the available experimental database, the 108Cd(α, n)111Sn reaction cross section was investigated at ten energies between 10.2 and 13.5 MeV. As this reaction at these energies is almost only sensitive on the α-decay width, the results were compared to statistical model calculations using different models for the α-OMP. The irradiation as well as the consecutive γ-ray counting were performed at the Institute for Nuclear Physics of the University of Cologne using the 10 MV FN-Tandem accelerator and the Cologne Clover Counting Setup. This setup consists of two clover- type high purity germanium (HPGe) detectors in a close face-to-face geometry to cover a solid angle of almost 4π.

Low-temperature dynamic nuclear polarization with helium-cooled samples and nitrogen-driven magic-angle spinning.

PubMed

Thurber, Kent; Tycko, Robert

2016-03-01

We describe novel instrumentation for low-temperature solid state nuclear magnetic resonance (NMR) with dynamic nuclear polarization (DNP) and magic-angle spinning (MAS), focusing on aspects of this instrumentation that have not been described in detail in previous publications. We characterize the performance of an extended interaction oscillator (EIO) microwave source, operating near 264 GHz with 1.5 W output power, which we use in conjunction with a quasi-optical microwave polarizing system and a MAS NMR probe that employs liquid helium for sample cooling and nitrogen gas for sample spinning. Enhancement factors for cross-polarized (13)C NMR signals in the 100-200 range are demonstrated with DNP at 25K. The dependences of signal amplitudes on sample temperature, as well as microwave power, polarization, and frequency, are presented. We show that sample temperatures below 30K can be achieved with helium consumption rates below 1.3 l/h. To illustrate potential applications of this instrumentation in structural studies of biochemical systems, we compare results from low-temperature DNP experiments on a calmodulin-binding peptide in its free and bound states. Published by Elsevier Inc.

Elastic and Inelastic Scattering of Neutrons from Neon and Argon: Impact on Neutrinoless Double-Beta Decay and Dark Matter Experimental Programs

NASA Astrophysics Data System (ADS)

MacMullin, Sean Patrick

In underground physics experiments, such as neutrinoless double-beta decay and dark matter searches, fast neutrons may be the dominant and potentially irreducible source of background. Experimental data for the elastic and inelastic scattering cross sections of neutrons from argon and neon, which are target and shielding materials of interest to the dark matter and neutrinoless double-beta decay communities, were previously unavailable. Unmeasured neutron scattering cross sections are often accounted for incorrectly in Monte-Carlo simulations. Elastic scattering cross sections were measured at the Triangle Universities Nuclear Laboratory (TUNL) using the neutron time-of-flight technique. Angular distributions for neon were measured at 5.0 and 8.0 MeV. One full angular distribution was measured for argon at 6.0 MeV. The cross-section data were compared to calculations using a global optical model. Data were also fit using the spherical optical model. These model fits were used to predict the elastic scattering cross section at unmeasured energies and also provide a benchmark where the global optical models are not well constrained. Partial gamma-ray production cross sections for (n,xngamma ) reactions in natural argon and neon were measured using the broad spectrum neutron beam at the Los Alamos Neutron Science Center (LANSCE). Neutron energies were determined using time of flight and resulting gamma rays from neutron-induced reactions were detected using the GErmanium Array for Neutron Induced Excitations (GEANIE). Partial gamma-ray production cross sections for six transitions in 40Ar, two transitions in 39Ar and the first excited state transitions is 20Ne and 22Ne were measured from threshold to a neutron energy where the gamma-ray yield dropped below the detection sensitivity. Measured (n,xngamma) cross sections were compared with calculations using the TALYS and CoH3 nuclear reaction codes. These new measurements will help to identify potential backgrounds in neutrinoless double-beta decay and dark matter experiments that use argon or neon. The measurements will also aid in the identification of neutron interactions in these experiments through the detection of gamma rays produced by ( n,xngamma) reactions.

The HELLAS2XMM survey. XI. Unveiling the nature of X-ray bright optically normal galaxies

NASA Astrophysics Data System (ADS)

Civano, F.; Mignoli, M.; Comastri, A.; Vignali, C.; Fiore, F.; Pozzetti, L.; Brusa, M.; La Franca, F.; Matt, G.; Puccetti, S.; Cocchia, F.

2007-12-01

Aims:X-ray bright optically normal galaxies (XBONGs) constitute a small but significant fraction of hard X-ray selected sources in recent Chandra and XMM-Newton surveys. Even though several possibilities were proposed to explain why a relatively luminous hard X-ray source does not leave any significant signature of its presence in terms of optical emission lines, the nature of XBONGs is still subject of debate. We aim to better understand their nature by means of a multiwavelength and morphological analysis of a small sample of these sources. Methods: Good-quality photometric near-infrared data (ISAAC/VLT) of four low-redshift (z = 0.1{-}0.3) XBONGs, selected from the HELLAS2XMM survey, have been used to search for the presence of the putative nucleus, applying the surface-brightness decomposition technique through the least-squares fitting program GALFIT. Results: The surface brightness decomposition allows us to reveal a nuclear point-like source, likely to be responsible for the X-ray emission, in two out of the four sources. The results indicate that moderate amounts of gas and dust, covering a large solid angle (possibly 4π) at the nuclear source, combined with the low nuclear activity, may explain the lack of optical emission lines. The third XBONG is associated with an X-ray extended source and no nuclear excess is detected in the near infrared at the limits of our observations. The last source is associated to a close (d≤ 1 arcsec) double system and the fitting procedure cannot achieve a firm conclusion. Based on observations made at the European Southern Observatory, Paranal, Chile (ESO Programme ID 69.A-0554).

Real time monitoring of water level and temperature in storage fuel pools through optical fibre sensors.

PubMed

Rizzolo, S; Périsse, J; Boukenter, A; Ouerdane, Y; Marin, E; Macé, J-R; Cannas, M; Girard, S

2017-08-18

We present an innovative architecture of a Rayleigh-based optical fibre sensor for the monitoring of water level and temperature inside storage nuclear fuel pools. This sensor, able to withstand the harsh constraints encountered under accidental conditions such as those pointed-out during the Fukushima-Daiichi event (temperature up to 100 °C and radiation dose level up to ~20 kGy), exploits the Optical Frequency Domain Reflectometry technique to remotely monitor a radiation resistant silica-based optical fibre i.e. its sensing probe. We validate the efficiency and the robustness of water level measurements, which are extrapolated from the temperature profile along the fibre length, in a dedicated test bench allowing the simulation of the environmental operating and accidental conditions. The conceived prototype ensures an easy, practical and no invasive integration into existing nuclear facilities. The obtained results represent a significant breakthrough and comfort the ability of the developed system to overcome both operating and accidental constraints providing the distributed profiles of the water level (0-to-5 m) and temperature (20-to-100 °C) with a resolution that in accidental condition is better than 3 cm and of ~0.5 °C respectively. These new sensors will be able, as safeguards, to contribute and reinforce the safety in existing and future nuclear power plants.

Application of Diamond Nanoparticles in Low-Energy Neutron Physics

PubMed Central

Nesvizhevsky, Valery; Cubitt, Robert; Lychagin, Egor; Muzychka, Alexei; Nekhaev, Grigory; Pignol, Guillaume; Protasov, Konstantin; Strelkov, Alexander

2010-01-01

Diamond, with its exceptionally high optical nuclear potential and low absorption cross-section, is a unique material for a series of applications in VCN (very cold neutron) physics and techniques. In particular, powder of diamond nanoparticles provides the best reflector for neutrons in the complete VCN energy range. It allowed also the first observation of quasi-specular reflection of cold neutrons (CN) from disordered medium. Effective critical velocity for such a quasi-specular reflection is higher than that for the best super-mirror. Nano-diamonds survive in high radiation fluxes; therefore they could be used, under certain conditions, in the vicinity of intense neutron sources.

A universal quantum module for quantum communication, computation, and metrology

NASA Astrophysics Data System (ADS)

Hanks, Michael; Lo Piparo, Nicolò; Trupke, Michael; Schmiedmayer, Jorg; Munro, William J.; Nemoto, Kae

2017-08-01

In this work, we describe a simple module that could be ubiquitous for quantum information based applications. The basic modules comprises a single NV- center in diamond embedded in an optical cavity, where the cavity mediates interactions between photons and the electron spin (enabling entanglement distribution and efficient readout), while the nuclear spins constitutes a long-lived quantum memories capable of storing and processing quantum information. We discuss how a network of connected modules can be used for distributed metrology, communication and computation applications. Finally, we investigate the possible use of alternative diamond centers (SiV/GeV) within the module and illustrate potential advantages.

Spectroscopic follow-up of variability-selected active galactic nuclei in the Chandra Deep Field South

NASA Astrophysics Data System (ADS)

Boutsia, K.; Leibundgut, B.; Trevese, D.; Vagnetti, F.

2009-04-01

Context: Supermassive black holes with masses of 10^5-109 M⊙ are believed to inhabit most, if not all, nuclear regions of galaxies, and both observational evidence and theoretical models suggest a scenario where galaxy and black hole evolution are tightly related. Luminous AGNs are usually selected by their non-stellar colours or their X-ray emission. Colour selection cannot be used to select low-luminosity AGNs, since their emission is dominated by the host galaxy. Objects with low X-ray to optical ratio escape even the deepest X-ray surveys performed so far. In a previous study we presented a sample of candidates selected through optical variability in the Chandra Deep Field South, where repeated optical observations were performed in the framework of the STRESS supernova survey. Aims: The analysis is devoted to breaking down the sample in AGNs, starburst galaxies, and low-ionisation narrow-emission line objects, to providing new information about the possible dependence of the emission mechanisms on nuclear luminosity and black-hole mass, and eventually studying the evolution in cosmic time of the different populations. Methods: We obtained new optical spectroscopy for a sample of variability selected candidates with the ESO NTT telescope. We analysed the new spectra, together with those existing in the literature and studied the distribution of the objects in U-B and B-V colours, optical and X-ray luminosity, and variability amplitude. Results: A large fraction (17/27) of the observed candidates are broad-line luminous AGNs, confirming the efficiency of variability in detecting quasars. We detect: i) extended objects which would have escaped the colour selection and ii) objects of very low X-ray to optical ratio, in a few cases without any X-ray detection at all. Several objects resulted to be narrow-emission line galaxies where variability indicates nuclear activity, while no emission lines were detected in others. Some of these galaxies have variability and X-ray to optical ratio close to active galactic nuclei, while others have much lower variability and X-ray to optical ratio. This result can be explained by the dilution of the nuclear light due to the host galaxy. Conclusions: Our results demonstrate the effectiveness of supernova search programmes to detect large samples of low-luminosity AGNs. A sizable fraction of the AGN in our variability sample had escaped X-ray detection (5/47) and/or colour selection (9/48). Spectroscopic follow-up to fainter flux limits is strongly encouraged. Based on observations collected at the European Southern Observatory, Chile, 080.B-0187(A).

Potential criminal adversaries of nuclear programs: a portrait

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

Jenkins, B.M.

1980-07-01

This paper examines the possibility that terrorists or other kinds of criminals might attempt to seize or sabotage a nuclear facility, steal nuclear material, or carry out other criminal activities in the nuclear domain which has created special problems for the security of nuclear programs. This paper analyzes the potential threat. Our tasks was to describe the potential criminal adversary, or rather the spectrum of potential adversaries who conceivably might carry out malevolent criminal actions against nuclear programs and facilities. We were concerned with both the motivations as well as the material and operational capabilities likely to be displayed bymore » various categories of potential nuclear adversaries.« less

Dual-window dual-bandwidth spectroscopic optical coherence tomography metric for qualitative scatterer size differentiation in tissues.

PubMed

Tay, Benjamin Chia-Meng; Chow, Tzu-Hao; Ng, Beng-Koon; Loh, Thomas Kwok-Seng

2012-09-01

This study investigates the autocorrelation bandwidths of dual-window (DW) optical coherence tomography (OCT) k-space scattering profile of different-sized microspheres and their correlation to scatterer size. A dual-bandwidth spectroscopic metric defined as the ratio of the 10% to 90% autocorrelation bandwidths is found to change monotonically with microsphere size and gives the best contrast enhancement for scatterer size differentiation in the resulting spectroscopic image. A simulation model supports the experimental results and revealed a tradeoff between the smallest detectable scatterer size and the maximum scatterer size in the linear range of the dual-window dual-bandwidth (DWDB) metric, which depends on the choice of the light source optical bandwidth. Spectroscopic OCT (SOCT) images of microspheres and tonsil tissue samples based on the proposed DWDB metric showed clear differentiation between different-sized scatterers as compared to those derived from conventional short-time Fourier transform metrics. The DWDB metric significantly improves the contrast in SOCT imaging and can aid the visualization and identification of dissimilar scatterer size in a sample. Potential applications include the early detection of cell nuclear changes in tissue carcinogenesis, the monitoring of healing tendons, and cell proliferation in tissue scaffolds.

Modelling the transport of optical photons in scintillation detectors for diagnostic and radiotherapy imaging

NASA Astrophysics Data System (ADS)

Roncali, Emilie; Mosleh-Shirazi, Mohammad Amin; Badano, Aldo

2017-10-01

Computational modelling of radiation transport can enhance the understanding of the relative importance of individual processes involved in imaging systems. Modelling is a powerful tool for improving detector designs in ways that are impractical or impossible to achieve through experimental measurements. Modelling of light transport in scintillation detectors used in radiology and radiotherapy imaging that rely on the detection of visible light plays an increasingly important role in detector design. Historically, researchers have invested heavily in modelling the transport of ionizing radiation while light transport is often ignored or coarsely modelled. Due to the complexity of existing light transport simulation tools and the breadth of custom codes developed by users, light transport studies are seldom fully exploited and have not reached their full potential. This topical review aims at providing an overview of the methods employed in freely available and other described optical Monte Carlo packages and analytical models and discussing their respective advantages and limitations. In particular, applications of optical transport modelling in nuclear medicine, diagnostic and radiotherapy imaging are described. A discussion on the evolution of these modelling tools into future developments and applications is presented. The authors declare equal leadership and contribution regarding this review.

Ozone, dust, smoke and humidity in nuclear winter

NASA Technical Reports Server (NTRS)

Turco, R. P.; Toon, O. B.; Ackerman, T. P.; Pollack, J. B.; Sagan, C.

1985-01-01

Recent correspondence on nuclear winter is commented on. Reasons are given for why the Tunguska meteor explosion may not be useful in calibrating the effects of a major nuclear exchange. The relationship between the optical depth of an aerosol cloud, the composition of the cloud, and its effect on sunlight intensity and climate are clarified. The significance of the Tambora eruption of 1815 and of historical fires for the nuclear winter theory are briefly discussed. The dispersion of smoke plumes from large fires is addressed, and water condensation and smoke scavenging are considered.

Vulnerability of OFDR-based distributed sensors to radiations

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

Rizzolo, S.; Dipartimento di Fisica e Chimica, Universita di Palermo, Viale delle Scienze Parco d'Orleans II, Ed. 17, 90128 Palermo; Areva Centre Technique, Boulevard de l'Industrie, 71200, Le Creusot

2015-07-01

Silica-based optical fibers have recently attracted much interest for their use in harsh environments such as the ones encountered in space, military or high energy physics applications. Small size, fast response, light weight and immunity to electromagnetic fields are favorable advantages that often become decisive for fiber sensing to be chosen over other conventional sensing technologies. As an important and representative example, Fukushima's accident highlighted weaknesses in the safety of nuclear power plants. Since, one of the strategic research axis of the nuclear industry is devoted to the development of novel technologies and sensors to enhance and reinforce the safetymore » in nuclear power plants, especially in the case of accidental conditions associated with a strong increase of the constraints applied to the fiber-based system. The objective of this research field is to develop classes of distributed fiber-based sensors using scattering-based techniques, powerful solutions for various measurands measurement. Optical fiber properties, indeed, depend on several external parameters such as temperature, strain and therefore the fiber itself can be used as the sensitive element. Different classes of fiber-based sensing techniques have been recently investigated such as Fiber Bragg Gratings (FBGs) for discrete measurements and Brillouin, Raman and Rayleigh [8,9] scattering based techniques for distributed measurements of various environmental parameters. Whereas Brillouin and Raman sensor resolutions remain in the range of one meter, the advantage of Rayleigh scattering based technique is that it offers very high spatial resolution from 1 cm down to few μm over several hundred meters of fiber length down to few meters respectively. For nuclear industry, integrating fibers-based sensors has to improve the performances (resolution, operating range,...) of security systems in current nuclear power plants (NPPs) and offers new alternative technologies that may overcome the issues identified for next generation of NPPs. Such integration will only be possible if the OFDR based systems are able to resist to the constraints associated with industrial environments, one of the most constraining being the presence of high level of radiations. In this work, we carry out a systematic study to highlight the OFDR interest and sensitivity to probe the optical samples at high irradiation dose levels. The responses of five optical fibers types, from radiation hardened to radiation sensitive ones, are investigated to explore the influence of both the material compositions and the γ-irradiation on the ODFR sensors. Using these samples, we should highlight the influence of the core dopant concentration on the observed radiation-induced changes as well as the difference observed when the cladding is either radiation resistant or radiation sensitive. Our samples were irradiated using a {sup 60}Co source facility reaching total doses varying from 1 MGy up to a maximum of 10 MGy. All the measurements are performed after diverse months from irradiation to study permanents effects induced from these high γ-rays doses. We'll present at the conference all the experimental results acquired and use them to estimate the potential of OFDR-based systems for operation in radiation environments. (authors)« less

Radioisotope Power Sources for MEMS Devices,

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

Blanchard, J.P.

2001-06-17

Microelectromechanical systems (MEMS) comprise a rapidly expanding research field with potential applications varying from sensors in airbags to more recent optical applications. Depending on the application, these devices often require an on-board power source for remote operation, especially in cases requiring operation for an extended period of time. Previously suggested power sources include fossil fuels and solar energy, but nuclear power sources may provide significant advantages for certain applications. Hence, the objective of this study is to establish the viability of using radioisotopes to power realistic MEMS devices. A junction-type battery was constructed using silicon and a {sup 63}Ni liquidmore » source. A source volume containing 64 {micro}Ci provided a power of {approx}0.07 nW. A more novel application of nuclear sources for MEMS applications involves the creation of a resonator that is driven by charge collection in a cantilever beam. Preliminary results have established the feasibility of this concept, and future work will optimize the design for various applications.« less

Correction of stain variations in nuclear refractive index of clinical histology specimens

PubMed Central

Uttam, Shikhar; Bista, Rajan K.; Hartman, Douglas J.; Brand, Randall E.; Liu, Yang

2011-01-01

For any technique to be adopted into a clinical setting, it is imperative that it seamlessly integrates with well-established clinical diagnostic workflow. We recently developed an optical microscopy technique—spatial-domain low-coherence quantitative phase microscopy (SL-QPM) that can extract the refractive index of the cell nucleus from the standard histology specimens on glass slides prepared via standard clinical protocols. This technique has shown great potential in detecting cancer with a better sensitivity than conventional pathology. A major hurdle in the clinical translation of this technique is the intrinsic variation among staining agents used in histology specimens, which limits the accuracy of refractive index measurements of clinical samples. In this paper, we present a simple and easily generalizable method to remove the effect of variations in staining levels on nuclear refractive index obtained with SL-QPM. We illustrate the efficacy of our correction method by applying it to variously stained histology samples from animal model and clinical specimens. PMID:22112118

Vibrational nonlinear optical properties of spatially confined weakly bound complexes.

PubMed

Zaleśny, Robert; Chołuj, Marta; Kozłowska, Justyna; Bartkowiak, Wojciech; Luis, Josep M

2017-09-13

This study focuses on the theoretical description of the influence of spatial confinement on the electronic and vibrational contributions to (hyper)polarizabilities of two dimeric hydrogen bonded systems, namely HCNHCN and HCNHNC. A two-dimensional analytical potential is employed to render the confining environment (e.g. carbon nanotube). Based on the results of the state-of-the-art calculations, performed at the CCSD(T)/aug-cc-pVTZ level of theory, we established that: (i) the influence of spatial confinement increases with increasing order of the electrical properties, (ii) the effect of spatial confinement is much larger in the case of the electronic than vibrational contribution (this holds for each order of the electrical properties) and (iii) the decrease in the static nuclear relaxation first hyperpolarizability upon the increase of confinement strength is mainly due to changes in the harmonic term, however, in the case of nuclear relaxation second hyperpolarizability the anharmonic terms contribute more to the drop of this property.

Optical Pumping of the Electronic and Nuclear Spin of Single Charge-Tunable Quantum Dots

DTIC Science & Technology

2005-02-02

Optical Pumping of the Electronic and Nuclear Spin of Single Charge-Tunable Quantum Dots A. S . Bracker,1 E. A. Stinaff,1 D. Gammon,1 M. E. Ware,1 J...G. Tischler,1 A. Shabaev,1 Al. L. Efros,1 D. Park,1 D. Gershoni,2 V. L. Korenev ,3 and I. A. Merkulov3 1Naval Research Laboratory, Washington, D.C...intensity (open circles), the PRL 94, 047402 (2005) P H Y S I C A L R E V I E W L E T T E R S week ending 4 FEBRUARY 2005 0031-9007=05=94(4)=047402(4

RadBall Technology Testing and MCNP Modeling of the Tungsten Collimator.

PubMed

Farfán, Eduardo B; Foley, Trevor Q; Coleman, J Rusty; Jannik, G Timothy; Holmes, Christopher J; Oldham, Mark; Adamovics, John; Stanley, Steven J

2010-01-01

The United Kingdom's National Nuclear Laboratory (NNL) has developed a remote, non-electrical, radiation-mapping device known as RadBall(™), which can locate and quantify radioactive hazards within contaminated areas of the nuclear industry. RadBall(™) consists of a colander-like outer shell that houses a radiation-sensitive polymer sphere. The outer shell works to collimate radiation sources and those areas of the polymer sphere that are exposed react, becoming increasingly more opaque, in proportion to the absorbed dose. The polymer sphere is imaged in an optical-CT scanner, which produces a high resolution 3D map of optical attenuation coefficients. Subsequent analysis of the optical attenuation matrix provides information on the spatial distribution of sources in a given area forming a 3D characterization of the area of interest. RadBall(™) has no power requirements and can be positioned in tight or hard-to reach locations. The RadBall(™) technology has been deployed in a number of technology trials in nuclear waste reprocessing plants at Sellafield in the United Kingdom and facilities of the Savannah River National Laboratory (SRNL). This study focuses on the RadBall(™) testing and modeling accomplished at SRNL.

RadBall™ Technology Testing and MCNP Modeling of the Tungsten Collimator

PubMed Central

Farfán, Eduardo B.; Foley, Trevor Q.; Coleman, J. Rusty; Jannik, G. Timothy; Holmes, Christopher J.; Oldham, Mark; Adamovics, John; Stanley, Steven J.

2010-01-01

The United Kingdom’s National Nuclear Laboratory (NNL) has developed a remote, non-electrical, radiation-mapping device known as RadBall™, which can locate and quantify radioactive hazards within contaminated areas of the nuclear industry. RadBall™ consists of a colander-like outer shell that houses a radiation-sensitive polymer sphere. The outer shell works to collimate radiation sources and those areas of the polymer sphere that are exposed react, becoming increasingly more opaque, in proportion to the absorbed dose. The polymer sphere is imaged in an optical-CT scanner, which produces a high resolution 3D map of optical attenuation coefficients. Subsequent analysis of the optical attenuation matrix provides information on the spatial distribution of sources in a given area forming a 3D characterization of the area of interest. RadBall™ has no power requirements and can be positioned in tight or hard-to reach locations. The RadBall™ technology has been deployed in a number of technology trials in nuclear waste reprocessing plants at Sellafield in the United Kingdom and facilities of the Savannah River National Laboratory (SRNL). This study focuses on the RadBall™ testing and modeling accomplished at SRNL. PMID:21617740

Radioluminescence and photoluminescence of Th:CaF2 crystals

PubMed Central

Stellmer, Simon; Schreitl, Matthias; Schumm, Thorsten

2015-01-01

We study thorium-doped CaF2 crystals as a possible platform for optical spectroscopy of the 229Th nuclear isomer transition. We anticipate two major sources of background signal that might cover the nuclear spectroscopy signal: VUV-photoluminescence, caused by the probe light, and radioluminescence, caused by the radioactive decay of 229Th and its daughters. We find a rich photoluminescence spectrum at wavelengths above 260 nm, and radioluminescence emission above 220 nm. This is very promising, as fluorescence originating from the isomer transition, predicted at a wavelength shorter than 200 nm, could be filtered spectrally from the crystal luminescence. Furthermore, we investigate the temperature-dependent decay time of the luminescence, as well as thermoluminescence properties. Our findings allow for an immediate optimization of spectroscopy protocols for both the initial search for the nuclear transition using synchrotron radiation, as well as future optical clock operation with narrow-linewidth lasers. PMID:26502749

Thermal effects in supernova matter

NASA Astrophysics Data System (ADS)

Constantinou, Constantinos

A crucial ingredient in simulations of core collapse supernova (SN) explosions is the equation of state (EOS) of nucleonic matter for densities extending from 10-7 fm-3 to 1 ffm-3, temperatures up to 50 MeV, and proton-to-baryon fraction in the range 0 to 1/2. SN explosions release 99% of the progenitor star's gravitational potential energy in the form of neutrinos and, additionally, they are responsible for populating the universe with elements heavier than 56Fe. Therefore, the importance of understanding this phenomenon cannot be overstated as it could shed light onto the underlying nuclear and neutrino physics. A realistic EOS of SN matter must incorporate the nucleon-nucleon interaction in a many-body environment. We treat this problem with a non-relativistic potential model as well as relativistic mean-field theoretical one. In the former approach, we employ the Skyrme-like Hamiltonian density constructed by Akmal, Pandharipande, and Ravenhall which takes into account the long scattering lengths of nucleons that determine the low density characteristics. In the latter, we use a Walecka-like Lagrangian density supplemented by non-linear interactions involving scalar, vector, and isovector meson exchanges, calibrated so that known properties of nuclear matter are reproduced. We focus on the bulk homogeneous phase and calculate its thermodynamic properties as functions of baryon density, temperature, and proton-to-baryon ratio. The exact numerical results are then compared to those in the degenerate and non-degenerate limits for which analytical formulae have been derived. We find that the two models bahave similarly for densities up to nuclear saturation but exhibit differences at higher densities most notably in the isospin susceptibilities, the chemical potentials, and the pressure. The importance of the correct momentum dependence in the single particle potential that fits optical potentials of nucleon-nucleus scattering was highlighted in the context of intermediate energy heavy-ion collisions. To explore the effect momentum-dependent interactions have on the thermal properties of dense matter we study a schematic model constructed by Welke et al. in which the appropriate momentum dependence that fits optical potential data is built through finite-range exchange forces of the Yukawa type. We look into the finite-temperature properties of this model in the context of infinite, isospin-symmetric nucleonic matter. The exact numerical results are compared to analytical ones in the quantum regime where we rely on Landau's Fermi-Liquid Theory, and in the classical regime where the state variables are obtained through a steepest descent calculation. Detailed comparisons with similarly calibrated Skyrme models are also performed. We find that the high-density behavior of the thermal pressure is once again a differentiating feature. We attribute this to the temperature dependence of the energy spectrum of the finite-range and the meson-exchange models which leads to a higher specific heat and thus a lower pressure.

Optical coherence tomography for nondestructive evaluation of fuel rod degradation

NASA Astrophysics Data System (ADS)

Renshaw, Jeremy B.; Jenkins, Thomas P.; Buckner, Benjamin D.; Friend, Brian

2015-03-01

Nuclear power plants regularly inspect fuel rods to ensure safe and reliable operation. Excessive corrosion can cause fuel failures which can have significant repercussions for the plant, including impacts on plant operation, worker exposure to radiation, and the plant's INPO rating. While plants typically inspect for fuel rod corrosion using eddy current techniques, these techniques have known issues with reliability in the presence of tenacious, ferromagnetic crud layers that can deposit during operation, and the nondestructive evaluation (NDE) inspection results can often be in error by a factor of 2 or 3. For this reason, alternative measurement techniques, such as Optical Coherence Tomography (OCT), have been evaluated that are not sensitive to the ferromagnetic nature of the crud. This paper demonstrates that OCT has significant potential to characterize the thickness of crud layers that can deposit on the surfaces of fuel rods during operation. Physical trials have been performed on simulated crud samples, and the resulting data show an apparent correlation between the crud layer thickness and the OCT signal.

Elastic and inelastic scattering of neutrons on 238U nucleus

NASA Astrophysics Data System (ADS)

Capote, R.; Trkov, A.; Sin, M.; Herman, M. W.; Soukhovitskiĩ, E. Sh.

2014-04-01

Advanced modelling of neutron induced reactions on the 238U nucleus is aimed at improving our knowledge of neutron scattering. Capture and fission channels are well constrained by available experimental data and neutron standard evaluation. A focus of this contribution is on elastic and inelastic scattering cross sections. The employed nuclear reaction model includes - a new rotational-vibrational dispersive optical model potential coupling the low-lying collective bands of vibrational character observed in even-even actinides; - the Engelbrecht-Weidenmüller transformation allowing for inclusion of compound-direct interference effects; - and a multi-humped fission barrier with absorption in the secondary well described within the optical model for fission. Impact of the advanced modelling on elastic and inelastic scattering cross sections including angular distributions and emission spectra is assessed both by comparison with selected microscopic experimental data and integral criticality benchmarks including measured reaction rates (e.g. JEMIMA, FLAPTOP and BIG TEN). Benchmark calculations provided feedback to improve the reaction modelling. Improvement of existing libraries will be discussed.

Nanoscale nuclear architecture for cancer diagnosis by spatial-domain low-coherence quantitative phase microscopy

NASA Astrophysics Data System (ADS)

Wang, Pin; Bista, Rajan K.; Khalbuss, Walid E.; Qiu, Wei; Staton, Kevin D.; Zhang, Lin; Brentnall, Teresa A.; Brand, Randall E.; Liu, Yang

2011-03-01

Alterations in nuclear architecture are the hallmark diagnostic characteristic of cancer cells. In this work, we show that the nuclear architectural characteristics quantified by spatial-domain low-coherence quantitative phase microscopy (SL-QPM), is more sensitive for the identification of cancer cells than conventional cytopathology. We demonstrated the importance of nuclear architectural characteristics in both an animal model of intestinal carcinogenesis - APC/Min mouse model and human cytology specimens with colorectal cancer by identifying cancer from cytologically noncancerous appearing cells. The determination of nanoscale nuclear architecture using this simple and practical optical instrument is a significant advance towards cancer diagnosis.

Electronic structures and magnetic/optical properties of metal phthalocyanine complexes

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

Baba, Shintaro; Suzuki, Atsushi, E-mail: suzuki@mat.usp.ac.jp; Oku, Takeo

2016-02-01

Electronic structures and magnetic / optical properties of metal phthalocyanine complexes were studied by quantum calculations using density functional theory. Effects of central metal and expansion of π orbital on aromatic ring as conjugation system on the electronic structures, magnetic, optical properties and vibration modes of infrared and Raman spectra of metal phthalocyanines were investigated. Electron and charge density distribution and energy levels near frontier orbital and excited states were influenced by the deformed structures varied with central metal and charge. The magnetic parameters of chemical shifts in {sup 13}C-nuclear magnetic resonance ({sup 13}C-NMR), principle g-tensor, A-tensor, V-tensor of electricmore » field gradient and asymmetry parameters derived from the deformed structures with magnetic interaction of nuclear quadruple interaction based on electron and charge density distribution with a bias of charge near ligand under crystal field.« less

On X-Ray Variability in Seyfert Galaxies

NASA Technical Reports Server (NTRS)

Turner, T. J.; George, I. M.; Nandra, K.; Turcan, D.

1999-01-01

This paper presents a quantification of the X-ray variability amplitude for 79 ASCA observations of 36 Seyfert 1 galaxies. We find that consideration of sources with the narrowest permitted lines in the optical band introduces scatter into the established correlation between X-ray variability and nuclear luminosity. Consideration of the X-ray spectral index and variability properties together shows distinct groupings in parameter space for broad and narrow-line Seyfert 1 galaxies, confirming previous studies. A strong correlation is found between hard X-ray variability and FWHM Hbeta. A range of nuclear mass and accretion rate across the Seyfert population can explain the differences observed in X-ray and optical properties. An attractive alternative model, which does not depend on any systematic difference in central mass, is that the circumnuclear gas of NLSy1s is different to BLSy1s in temperature, optical depth, density or geometry.

SPECTRAL DOMAIN VERSUS SWEPT SOURCE OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY OF THE RETINAL CAPILLARY PLEXUSES IN SICKLE CELL MACULOPATHY.

PubMed

Jung, Jesse J; Chen, Michael H; Frambach, Caroline R; Rofagha, Soraya; Lee, Scott S

2018-01-01

To compare the spectral domain and swept source optical coherence tomography angiography findings in two cases of sickle cell maculopathy. A 53-year-old man and a 24-year-old man both with sickle cell disease (hemoglobin SS) presented with no visual complaints; Humphrey visual field testing demonstrated asymptomatic paracentral scotomas that extended nasally in the involved eyes. Clinical examination and multimodal imaging including spectral domain and swept source optical coherence tomography, and spectral domain optical coherence tomography angiography and swept source optical coherence tomography angiography (Carl Zeiss Meditec Inc, Dublin, CA) were performed. Fundus examination of both patients revealed subtle thinning of the macula. En-face swept source optical coherence tomography confirmed the extent of the thinning correlating with the functional paracentral scotomas on Humphrey visual field. Swept source optical coherence tomography B-scan revealed multiple confluent areas of inner nuclear thinning and significant temporal retinal atrophy. En-face 6 × 6-mm spectral domain optical coherence tomography angiography of the macula demonstrated greater loss of the deep capillary plexus compared with the superficial capillary plexus. Swept source optical coherence tomography angiography 12 × 12-mm imaging captured the same macular findings and loss of both plexuses temporally outside the macula. In these two cases of sickle cell maculopathy, deep capillary plexus ischemia is more extensive within the macula, whereas both the superficial capillary plexus and deep capillary plexus are involved outside the macula likely due to the greater oxygen demands and watershed nature of these areas. Swept source optical coherence tomography angiography clearly demonstrates the angiographic extent of the disease correlating with the Humphrey visual field scotomas and confluent areas of inner nuclear atrophy.

Investigation of nuclear nano-morphology marker as a biomarker for cancer risk assessment using a mouse model

NASA Astrophysics Data System (ADS)

Bista, Rajan K.; Uttam, Shikhar; Hartman, Douglas J.; Qiu, Wei; Yu, Jian; Zhang, Lin; Brand, Randall E.; Liu, Yang

2012-06-01

The development of accurate and clinically applicable tools to assess cancer risk is essential to define candidates to undergo screening for early-stage cancers at a curable stage or provide a novel method to monitor chemoprevention treatments. With the use of our recently developed optical technology--spatial-domain low-coherence quantitative phase microscopy (SL-QPM), we have derived a novel optical biomarker characterized by structure-derived optical path length (OPL) properties from the cell nucleus on the standard histology and cytology specimens, which quantifies the nano-structural alterations within the cell nucleus at the nanoscale sensitivity, referred to as nano-morphology marker. The aim of this study is to evaluate the feasibility of the nuclear nano-morphology marker from histologically normal cells, extracted directly from the standard histology specimens, to detect early-stage carcinogenesis, assess cancer risk, and monitor the effect of chemopreventive treatment. We used a well-established mouse model of spontaneous carcinogenesis--ApcMin mice, which develop multiple intestinal adenomas (Min) due to a germline mutation in the adenomatous polyposis coli (Apc) gene. We found that the nuclear nano-morphology marker quantified by OPL detects the development of carcinogenesis from histologically normal intestinal epithelial cells, even at an early pre-adenomatous stage (six weeks). It also exhibits a good temporal correlation with the small intestine that parallels the development of carcinogenesis and cancer risk. To further assess its ability to monitor the efficacy of chemopreventive agents, we used an established chemopreventive agent, sulindac. The nuclear nano-morphology marker is reversed toward normal after a prolonged treatment. Therefore, our proof-of-concept study establishes the feasibility of the SL-QPM derived nuclear nano-morphology marker OPL as a promising, simple and clinically applicable biomarker for cancer risk assessment and evaluation of chemopreventive treatment.

Flexible corner cube retroreflector array for temperature and strain sensing† †Electronic supplementary information (ESI) available. See DOI: 10.1039/c7ra13284k

PubMed Central

Khalid, Muhammad Waqas; Ahmed, Rajib; Yetisen, Ali K.

2018-01-01

Optical sensors for detecting temperature and strain play a crucial role in the analysis of environmental conditions and real-time remote sensing. However, the development of a single optical device that can sense temperature and strain simultaneously remains a challenge. Here, a flexible corner cube retroreflector (CCR) array based on passive dual optical sensing (temperature and strain) is demonstrated. A mechanical embossing process was utilised to replicate a three-dimensional (3D) CCR array in a soft flexible polymer film. The fabricated flexible CCR array samples were experimentally characterised through reflection measurements followed by computational modelling. As fabricated samples were illuminated with a monochromatic laser beam (635, 532, and 450 nm), a triangular shape reflection was obtained at the far-field. The fabricated flexible CCR array samples tuned retroreflected light based on external stimuli (temperature and strain as an applied force). For strain and temperature sensing, an applied force and temperature, in the form of weight suspension, and heat flow was applied to alter the replicated CCR surface structure, which in turn changed its optical response. Directional reflection from the heated flexible CCR array surface was also measured with tilt angle variation (max. up to 10°). Soft polymer CCRs may have potential in remote sensing applications, including measuring the temperature in space and in nuclear power stations. PMID:29568510

Radiation hardening commercial off-the-shelf erbium doped fibers by optimal photo-annealing source

NASA Astrophysics Data System (ADS)

Peng, Tz-Shiuan; Liu, Ren-Young; Lin, Yen-Chih; Mao, Ming-Hua; Wang, Lon A.

2017-09-01

Erbium doped fibers (EDFs) based devices are widely employed in space for optical communication [1], remote sensing [2], and navigation applications, e.g. interferometric fiber optic gyroscope (IFOG). However, the EDF suffers severely radiation induced attenuation (RIA) in radiation environments, e.g. space applications and nuclear reactors [3].

An Optical Disk-Based Information Retrieval System.

ERIC Educational Resources Information Center

Bender, Avi

1988-01-01

Discusses a pilot project by the Nuclear Regulatory Commission to apply optical disk technology to the storage and retrieval of documents related to its high level waste management program. Components and features of the microcomputer-based system which provides full-text and image access to documents are described. A sample search is included.…

Amorphous and crystalline optical materials used as instruments for high gamma radiation doses estimations

NASA Astrophysics Data System (ADS)

Ioan, M.-R.

2016-06-01

Nuclear radiation induce some changes to the structure of exposed materials. The main effect of ionizing radiation when interacting with optical materials is the occurrence of color centers, which are quantitatively proportional to the up-taken doses. In this paper, a relation between browning effect magnitude and dose values was found. Using this relation, the estimation of a gamma radiation dose can be done. By using two types of laser wavelengths (532 nm and 633 nm), the optical powers transmitted thru glass samples irradiated to different doses between 0 and 59.1 kGy, were measured and the associated optical browning densities were determined. The use of laser light gives the opportunity of using its particularities: monochromaticity, directionality and coherence. Polarized light was also used for enhancing measurements quality. These preliminary results bring the opportunity of using glasses as detectors for the estimation of the dose in a certain point in space and for certain energy, especially in particles accelerators experiments, where the occurred nuclear reactions are involving the presence of high gamma rays fields.

Optical microwell assay of membrane transport kinetics.

PubMed

Kiskin, Nikolai I; Siebrasse, Jan P; Peters, Reiner

2003-10-01

In optical single transporter recording, membranes are firmly attached to flat solid substrates containing small wells or test compartments (TC). Transport of fluorescent molecules through TC-spanning membrane patches is induced by solution change and recorded by confocal microscopy. Previously, track-etched membrane filters were used to create solid substrates containing populations of randomly distributed TCs. In this study the possibilities offered by orderly TC arrays as created by laser microdrilling were explored. A theoretical framework was developed taking the convolution of membrane transport, solution change, and diffusion into account. The optical properties of orderly TC arrays were studied and the kinetics of solution change measured. Export and import through the nuclear pore complex (NPC) was analyzed in isolated envelopes of Xenopus oocyte nuclei. In accordance with previous reports nuclear transport receptor NTF2, which binds directly to NPC proteins, was found to be translocated much faster than "inert" molecules of similar size. Unexpectedly, NXT1, a homolog of NTF2 reportedly unable to bind to NPC proteins directly, was translocated as fast as NTF2. Thus, microstructured TC arrays were shown to provide optical single transporter recording with a new basis.

Localization microscopy of DNA in situ using Vybrant{sup ®} DyeCycle™ Violet fluorescent probe: A new approach to study nuclear nanostructure at single molecule resolution

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

Żurek-Biesiada, Dominika; Szczurek, Aleksander T.; Prakash, Kirti

Higher order chromatin structure is not only required to compact and spatially arrange long chromatids within a nucleus, but have also important functional roles, including control of gene expression and DNA processing. However, studies of chromatin nanostructures cannot be performed using conventional widefield and confocal microscopy because of the limited optical resolution. Various methods of superresolution microscopy have been described to overcome this difficulty, like structured illumination and single molecule localization microscopy. We report here that the standard DNA dye Vybrant{sup ®} DyeCycle™ Violet can be used to provide single molecule localization microscopy (SMLM) images of DNA in nuclei ofmore » fixed mammalian cells. This SMLM method enabled optical isolation and localization of large numbers of DNA-bound molecules, usually in excess of 10{sup 6} signals in one cell nucleus. The technique yielded high-quality images of nuclear DNA density, revealing subdiffraction chromatin structures of the size in the order of 100 nm; the interchromatin compartment was visualized at unprecedented optical resolution. The approach offers several advantages over previously described high resolution DNA imaging methods, including high specificity, an ability to record images using a single wavelength excitation, and a higher density of single molecule signals than reported in previous SMLM studies. The method is compatible with DNA/multicolor SMLM imaging which employs simple staining methods suited also for conventional optical microscopy. - Highlights: • Super-resolution imaging of nuclear DNA with Vybrant Violet and blue excitation. • 90nm resolution images of DNA structures in optically thick eukaryotic nuclei. • Enhanced resolution confirms the existence of DNA-free regions inside the nucleus. • Optimized imaging conditions enable multicolor super-resolution imaging.« less

Three-Dimensional Reconstruction of Nuclear Envelope Architecture Using Dual-Color Metal-Induced Energy Transfer Imaging.

PubMed

Chizhik, Anna M; Ruhlandt, Daja; Pfaff, Janine; Karedla, Narain; Chizhik, Alexey I; Gregor, Ingo; Kehlenbach, Ralph H; Enderlein, Jörg

2017-12-26

The nuclear envelope, comprising the inner and the outer nuclear membrane, separates the nucleus from the cytoplasm and plays a key role in cellular functions. Nuclear pore complexes (NPCs), which are embedded in the nuclear envelope, control transport of macromolecules between the two compartments. Here, using dual-color metal-induced energy transfer (MIET), we determine the axial distance between Lap2β and Nup358 as markers for the inner nuclear membrane and the cytoplasmic side of the NPC, respectively. Using MIET imaging, we reconstruct the 3D profile of the nuclear envelope over the whole basal area, with an axial resolution of a few nanometers. This result demonstrates that optical microscopy can achieve nanometer axial resolution in biological samples and without recourse to complex interferometric approaches.

Stimulated Raman adiabatic control of a nuclear spin in diamond

NASA Astrophysics Data System (ADS)

Coto, Raul; Jacques, Vincent; Hétet, Gabriel; Maze, Jerónimo R.

2017-08-01

Coherent manipulation of nuclear spins is a highly desirable tool for both quantum metrology and quantum computation. However, most of the current techniques to control nuclear spins lack fast speed, impairing their robustness against decoherence. Here, based on stimulated Raman adiabatic passage, and its modification including shortcuts to adiabaticity, we present a fast protocol for the coherent manipulation of nuclear spins. Our proposed Λ scheme is implemented in the microwave domain and its excited-state relaxation can be optically controlled through an external laser excitation. These features allow for the initialization of a nuclear spin starting from a thermal state. Moreover we show how to implement Raman control for performing Ramsey spectroscopy to measure the dynamical and geometric phases acquired by nuclear spins.

One-shot calculation of temperature-dependent optical spectra and phonon-induced band-gap renormalization

NASA Astrophysics Data System (ADS)

Zacharias, Marios; Giustino, Feliciano

2016-08-01

Recently, Zacharias et al. [Phys. Rev. Lett. 115, 177401 (2015), 10.1103/PhysRevLett.115.177401] developed an ab initio theory of temperature-dependent optical absorption spectra and band gaps in semiconductors and insulators. In that work, the zero-point renormalization and the temperature dependence were obtained by sampling the nuclear wave functions using a stochastic approach. In the present work, we show that the stochastic sampling of Zacharias et al. can be replaced by fully deterministic supercell calculations based on a single optimal configuration of the atomic positions. We demonstrate that a single calculation is able to capture the temperature-dependent band-gap renormalization including quantum nuclear effects in direct-gap and indirect-gap semiconductors, as well as phonon-assisted optical absorption in indirect-gap semiconductors. In order to demonstrate this methodology, we calculate from first principles the temperature-dependent optical absorption spectra and the renormalization of direct and indirect band gaps in silicon, diamond, and gallium arsenide, and we obtain good agreement with experiment and with previous calculations. In this work we also establish the formal connection between the Williams-Lax theory of optical transitions and the related theories of indirect absorption by Hall, Bardeen, and Blatt, and of temperature-dependent band structures by Allen and Heine. The present methodology enables systematic ab initio calculations of optical absorption spectra at finite temperature, including both direct and indirect transitions. This feature will be useful for high-throughput calculations of optical properties at finite temperature and for calculating temperature-dependent optical properties using high-level theories such as G W and Bethe-Salpeter approaches.

Spin microscope based on optically detected magnetic resonance

DOEpatents

Berman, Gennady P [Los Alamos, NM; Chernobrod, Boris M [Los Alamos, NM

2010-06-29

The invention relates to scanning magnetic microscope which has a photoluminescent nanoprobe implanted in the tip apex of an atomic force microscope (AFM), a scanning tunneling microscope (STM) or a near-field scanning optical microscope (NSOM) and exhibits optically detected magnetic resonance (ODMR) in the vicinity of unpaired electron spins or nuclear magnetic moments in the sample material. The described spin microscope has demonstrated nanoscale lateral resolution and single spin sensitivity for the AFM and STM embodiments.

Spin microscope based on optically detected magnetic resonance

DOEpatents

Berman, Gennady P.; Chernobrod, Boris M.

2009-11-10

The invention relates to scanning magnetic microscope which has a photoluminescent nanoprobe implanted in the tip apex of an atomic force microscope (AFM), a scanning tunneling microscope (STM) or a near-field scanning optical microscope (NSOM) and exhibits optically detected magnetic resonance (ODMR) in the vicinity of impaired electron spins or nuclear magnetic moments in the sample material. The described spin microscope has demonstrated nanoscale lateral resolution and single spin sensitivity for the AFM and STM embodiments.

Spin microscope based on optically detected magnetic resonance

DOEpatents

Berman, Gennady P.; Chernobrod, Boris M.

2007-12-11

The invention relates to scanning magnetic microscope which has a photoluminescent nanoprobe implanted in the tip apex of an atomic force microscope (AFM), a scanning tunneling microscope (STM) or a near-field scanning optical microscope (NSOM) and exhibits optically detected magnetic resonance (ODMR) in the vicinity of unpaired electron spins or nuclear magnetic moments in the sample material. The described spin microscope has demonstrated nanoscale lateral resolution and single spin sensitivity for the AFM and STM embodiments.

Spin microscope based on optically detected magnetic resonance

DOEpatents

Berman, Gennady P [Los Alamos, NM; Chernobrod, Boris M [Los Alamos, NM

2010-07-13

The invention relates to scanning magnetic microscope which has a photoluminescent nanoprobe implanted in the tip apex of an atomic force microscope (AFM), a scanning tunneling microscope (STM) or a near-field scanning optical microscope (NSOM) and exhibits optically detected magnetic resonance (ODMR) in the vicinity of unpaired electron spins or nuclear magnetic moments in the sample material. The described spin microscope has demonstrated nanoscale lateral resolution and single spin sensitivity for the AFM and STM embodiments.

Spin microscope based on optically detected magnetic resonance

DOEpatents

Berman, Gennady P [Los Alamos, NM; Chernobrod, Boris M [Los Alamos, NM

2009-10-27

The invention relates to scanning magnetic microscope which has a photoluminescent nanoprobe implanted in the tip apex of an atomic force microscope (AFM), a scanning tunneling microscope (STM) or a near-field scanning optical microscope (NSOM) and exhibits optically detected magnetic resonance (ODMR) in the vicinity of unpaired electron spins or nuclear magnetic moments in the sample material. The described spin microscope has demonstrated nanoscale lateral resolution and single spin sensitivity for the AFM and STM embodiments.

Alterations in Retinal Layer Thickness and Reflectance at Different Stages of Diabetic Retinopathy by En Face Optical Coherence Tomography

PubMed Central

Wanek, Justin; Blair, Norman P.; Chau, Felix Y.; Lim, Jennifer I.; Leiderman, Yannek I.; Shahidi, Mahnaz

2016-01-01

Purpose This article reports a method for en face optical coherence tomography (OCT) imaging and quantitative assessment of alterations in both thickness and reflectance of individual retinal layers at different stages of diabetic retinopathy (DR). Methods High-density OCT raster volume scans were acquired in 29 diabetic subjects divided into no DR (NDR) or non-proliferative DR (NPDR) groups and 22 control subjects (CNTL). A customized image segmentation method identified eight retinal layer interfaces and generated en face thickness maps and reflectance images for nerve fiber layer (NFL), ganglion cell and inner plexiform layers (GCLIPL), inner nuclear layer (INL), outer plexiform layer (OPL), outer nuclear layer (ONL), photoreceptor outer segment layer (OSL), and retinal pigment epithelium (RPE). Mean thickness and intensity values were calculated in nine macular subfields for each retinal layer. Results En face thickness maps and reflectance images of retinal layers in CNTL subjects corresponded to normal retinal anatomy. Total retinal thickness correlated negatively with age in nasal subfields (R ≤−0.31; P ≤ 0.03, N = 51). In NDR subjects, NFL and OPL thickness were decreased (P = 0.05), and ONL thickness was increased (P = 0.04) compared to CNTL. In NPDR subjects, GCLIPL thickness was increased in perifoveal subfields (P < 0.05) and INL intensity was higher in all macular subfields (P = 0.04) compared to CNTL. Conclusions Depth and spatially resolved retinal thickness and reflectance measurements are potential biomarkers for assessment and monitoring of DR. PMID:27409491

Fusion and elastic scattering of 6Li + 58Ni at low energies

NASA Astrophysics Data System (ADS)

Aguilera, Elí F.; Amador-Valenzuela, Paulina; Martinez-Quiroz, Enrique; Lizcano, David; Garcia-Flores, Araceli; Kolata, James J.

2017-11-01

Sub-barrier fusion cross sections (σfus) for the 6Li + 58Ni system, obtained from the respective evaporation protons, are examined in the present work. With respect to expectations of a simple one-dimensional barrier penetration model, a large enhancement of the data is observed. Good consistency with equivalent data reported previously for similar systems is found. A comparison with total reaction cross sections (σR), deduced from elastic scattering measurements reported previously, indicates that σfus is close to σR within the measured energy range. To estimate the contribution of complete fusion (CF), an optical model analysis of the elastic scattering data is performed where CF is identified with the absorption in a short range volume potential. A surface polarization potential is added to the bare nuclear potential to simulate the effect of peripheral reactions. The results obtained indicate that other mechanisms different from CF may be dominant, especially in the lower energy region.

Profile and Determinants of Retinal Optical Intensity in Normal Eyes with Spectral Domain Optical Coherence Tomography.

PubMed

Chen, Binyao; Gao, Enting; Chen, Haoyu; Yang, Jianling; Shi, Fei; Zheng, Ce; Zhu, Weifang; Xiang, Dehui; Chen, Xinjian; Zhang, Mingzhi

2016-01-01

To investigate the profile and determinants of retinal optical intensity in normal subjects using 3D spectral domain optical coherence tomography (SD OCT). A total of 231 eyes from 231 healthy subjects ranging in age from 18 to 80 years were included and underwent a 3D OCT scan. Forty-four eyes were randomly chosen to be scanned by two operators for reproducibility analysis. Distribution of optical intensity of each layer and regions specified by the Early Treatment of Diabetic Retinopathy Study (ETDRS) were investigated by analyzing the OCT raw data with our automatic graph-based algorithm. Univariate and multivariate analyses were performed between retinal optical intensity and sex, age, height, weight, spherical equivalent (SE), axial length, image quality, disc area and rim/disc area ratio (R/D area ratio). For optical intensity measurements, the intraclass correlation coefficient of each layer ranged from 0.815 to 0.941, indicating good reproducibility. Optical intensity was lowest in the central area of retinal nerve fiber layer, ganglion cell layer, inner plexiform layer, inner nuclear layer, outer plexiform layer and photoreceptor layer, except for the retinal pigment epithelium (RPE). Optical intensity was positively correlated with image quality in all retinal layers (0.553<β<0.851, p<0.01), and negatively correlated with age in most retinal layers (-0.362<β<-0.179, p<0.01), except for the RPE (β = 0.456, p<0.01), outer nuclear layer and photoreceptor layer (p>0.05). There was no relationship between retinal optical intensity and sex, height, weight, SE, axial length, disc area and R/D area ratio. There was a specific pattern of distribution of retinal optical intensity in different regions. The optical intensity was affected by image quality and age. Image quality can be used as a reference for normalization. The effect of age needs to be taken into consideration when using OCT for diagnosis.

Toward Quantum Non-demolition of nitrogen-vacancy centers in diamond

NASA Astrophysics Data System (ADS)

Hodges, Jonathan; Jiang, Liang; Maze, Jeronimo; Lukin, Mikhail

2009-05-01

The nitrogen-vacancy color center (NVC) in diamond, which possesses a long-lived electronic spin (S=1) ground state with optical addressability, is a promising platform for quantum networks, single-photon sources, and nanoscale magnetometers. Here, we make use of a nuclear spin based quantum memory to demonstrate quantum non-demolition measurement of a solid-state spin qubit. By entangling the electron spin with a polarized carbon-13 spin (I=1/2) in the lattice, we have repeated optical measurement of the electron spin for the polarization lifetime of the nuclear spin. We show relative improvements in signal-to-noise of greater than 300%. These techniques can be used to improve the sensitivity of NVC magnetometers.

Excitation of Nuclei and Atoms Trapping in Optical Fields of High Intensity

DTIC Science & Technology

2006-11-01

the new relativistic wave equation for half- spin particle interacting with the electromagnetic field. The proposed equation is Lorentz and gauge ...CONTENTS Task 1. Gamma-ray laser with hidden inversion of nuclear state populations 3 Introduction 3 Recoil-accompanied nuclear...31 Task 2. Extended ensemble of monoenergetic atoms 33 Introduction 33 Results 37 Conclusion 66

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

Ramirez, A. P. D.; Vanhoy, J. R.; Hicks, S. F.

Elastic and inelastic differential cross sections for neutron scattering from 56Fe have been measured for several incident energies from 1.30 to 7.96 MeV at the University of Kentucky Accelerator Laboratory. Scattered neutrons were detected using a C 6D 6 liquid scintillation detector using pulse-shape discrimination and time-of-flight techniques. The deduced cross sections have been compared with previously reported data, predictions from evaluation databases ENDF, JENDL, and JEFF, and theoretical calculations performed using different optical model potentials using the TALYS and EMPIRE nuclear reaction codes. The coupled-channel calculations based on the vibrational and soft-rotor models are found to describe the experimentalmore » (n,n 0) and (n,n 1) cross sections well.« less

To the solar foci

NASA Technical Reports Server (NTRS)

Sonnabend, D.

1979-01-01

Earlier authors showed that the sun is likely to act as a lens for gravitational radiation, with focui in the outer solar system. They suggested that missions to these foci have the potential of directly measuring the density structure of the sun. Other applications include gravitational wave astronomy and tests of general relativity. This idea is reexamined, concentrating on the engineering aspects of focal missions; primarily spacecraft design and performance. Other topics studied include solar optics, gravitational wave detectors, navigation, and the design of missions for different purposes. Specifically, it is shown that shuttle launched chemical rockets have a substantial capability for reaching some foci; and that all can be reached with large payloads using nuclear isotope-electric propulsion.

High levels of absorption in orientation-unbiased, radio-selected 3CR Active Galaxies

NASA Astrophysics Data System (ADS)

Wilkes, Belinda J.; Haas, Martin; Barthel, Peter; Leipski, Christian; Kuraszkiewicz, Joanna; Worrall, Diana; Birkinshaw, Mark; Willner, Steven P.

2014-08-01

A critical problem in understanding active galaxies (AGN) is the separation of intrinsic physical differences from observed differences that are due to orientation. Obscuration of the active nucleus is anisotropic and strongly frequency dependent leading to complex selection effects for observations in most wavebands. These can only be quantified using a sample that is sufficiently unbiased to test orientation effects. Low-frequency radio emission is one way to select a close-to orientation-unbiased sample, albeit limited to the minority of AGN with strong radio emission.Recent Chandra, Spitzer and Herschel observations combined with multi-wavelength data for a complete sample of high-redshift (1 24.2) = 2.5:1.4:1 in these high-luminosity (log L(0.3-8keV) ~ 44-46) sources. These ratios are consistent with current expectations based on modelingthe Cosmic X-ray Background. A strong correlation with radio orientation constrains the geometry of the obscuring disk/torus to have a ~60 degree opening angle and ~12 degree Compton-thick cross-section. The deduced ~50% obscured fraction of the population contrasts with typical estimates of ~20% obscured in optically- and X-ray-selected high-luminosity samples. Once the primary nuclear emission is obscured, AGN X-ray spectra are frequently dominated by unobscured non-nuclear or scattered nuclear emission which cannot be distinguished from direct nuclear emission with a lower obscuration level unless high quality data is available. As a result, both the level of obscuration and the estimated instrinsic luminosities of highly-obscured AGN are likely to be significantly (*10-1000) underestimated for 25-50% of the population. This may explain the lower obscured fractions reported for optical and X-ray samples which have no independent measure of the AGN luminosity. Correcting AGN samples for these underestimated luminosities would result in flatter derived luminosity functions and potentially change their evolution.

Large scale obscuration and related climate effects open literature bibliography

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

Russell, N.A.; Geitgey, J.; Behl, Y.K.

1994-05-01

Large scale obscuration and related climate effects of nuclear detonations first became a matter of concern in connection with the so-called ``Nuclear Winter Controversy`` in the early 1980`s. Since then, the world has changed. Nevertheless, concern remains about the atmospheric effects of nuclear detonations, but the source of concern has shifted. Now it focuses less on global, and more on regional effects and their resulting impacts on the performance of electro-optical and other defense-related systems. This bibliography reflects the modified interest.

Nuclear-Spin Gyroscope Based on an Atomic Co-Magnetometer

NASA Technical Reports Server (NTRS)

Romalis, Michael; Komack, Tom; Ghost, Rajat

2008-01-01

An experimental nuclear-spin gyroscope is based on an alkali-metal/noblegas co-magnetometer, which automatically cancels the effects of magnetic fields. Whereas the performances of prior nuclear-spin gyroscopes are limited by sensitivity to magnetic fields, this gyroscope is insensitive to magnetic fields and to other external perturbations. In addition, relative to prior nuclear-spin gyroscopes, this one exhibits greater sensitivity to rotation. There is commercial interest in development of small, highly sensitive gyroscopes. The present experimental device could be a prototype for development of nuclear spin gyroscopes suitable for navigation. In comparison with fiber-optic gyroscopes, these gyroscopes would draw less power and would be smaller, lighter, more sensitive, and less costly.

Modifications of the optical properties for DAM-ADC nuclear track detector exposed to alpha particles

NASA Astrophysics Data System (ADS)

Rammah, Y. S.; Awad, E. M.

2018-05-01

Modifications of the optical properties of diallyl maleate-allyl diglycol carbonate (DAM-ADC) nuclear detector induced by alpha particles are described. DAM-ADC samples were irradiated perpendicularly by thin 241Am disk source that emits alpha particles with 5.48 MeV. The optical absorption has been measured using the ultraviolet-visible (UV-1100) spectroscopy. It was found that DAM-ADC polymer shows substantial modifications in its optical characteristics upon irradiated with alpha particles with different energies. The optical energy band gap (Egap) for the detector was calculated for the direct and the indirect allowed transitions in K-space using two approaches (Tauc's model and absorption spectrum fitting (ASF) method). Urbach's energy (Ea), number of carbon atoms per conjugated length (N), number of carbon atoms per cluster (M), and refractive index (n) for the present samples were determined. Results reveal that the values of energy gap in direct transition are greater than those of indirect, before and after irradiation. (Egap), (Ea), (N), (M), and (n) of the present samples are changed significantly with irradiation time and value of alpha energy. Results reflect the possibility of using DAM-ADC polymer track detectors to estimate alpha particle energies using the variation of the absorbance.

Space optics; Proceedings of the Seminar, Huntsville, Ala., May 22-24, 1979

NASA Technical Reports Server (NTRS)

Wyman, C. L.

1979-01-01

The seminar focused on infrared systems, the space telescope, new design for space astronomy, future earth resources systems, and planetary systems. Papers were presented on infrared astronomy satellite, infrared telescope on Spacelab 2, design alternatives for the Shuttle Infrared Telescope Facility, Spacelab 2 infrared telescope cryogenic system, geometrical theory of diffraction and telescope stray-light analysis, Space Telescope scientific instruments, faint-object spectrograph for the Space Telescope, light scattering from multilayer optics, bidirectional reflectance distribution function measurements of stray light suppression coatings for the Space Telescope, optical fabrication of a 60-in. mirror, interferogram analysis for space optics, nuclear-pumped lasers for space application, geophysical fluid flow experiment, coherent rays for optical astronomy in space, optical system with fiber-optical elements, and Pioneer-Venus solar flux radiometer.

Experimental Studies of Nuclear Physics Input for γ -Process Nucleosynthesis

NASA Astrophysics Data System (ADS)

Scholz, Philipp; Heim, Felix; Mayer, Jan; Netterdon, Lars; Zilges, Andreas

The predictions of reaction rates for the γ process in the scope of the Hauser-Feshbach statistical model crucially depend on nuclear physics input-parameters as optical-model potentials (OMP) or γ -ray strength functions. Precise cross-section measurements at astrophysically relevant energies help to constrain adopted models and, therefore, to reduce the uncertainties in the theoretically predicted reaction rates. During the last years, several cross-sections of charged-particle induced reactions on heavy nuclei have been measured at the University of Cologne. Either by means of the in-beam method at the HORUS γ -ray spectrometer or the activation technique using the Cologne Clover Counting Setup, total and partial cross-sections could be used to further constrain different models for nuclear physics input-parameters. It could be shown that modifications on the α -OMP in the case of the 112Sn(α , γ ) reaction also improve the description of the recently measured cross sections of the 108Cd(α , γ ) and 108Cd(α , n) reaction and other reactions as well. Partial cross-sections of the 92Mo(p, γ ) reaction were used to improve the γ -strength function model in 93Tc in the same way as it was done for the 89Y(p, γ ) reaction.

Towards quantum networks of single spins: analysis of a quantum memory with an optical interface in diamond.

PubMed

Blok, M S; Kalb, N; Reiserer, A; Taminiau, T H; Hanson, R

2015-01-01

Single defect centers in diamond have emerged as a powerful platform for quantum optics experiments and quantum information processing tasks. Connecting spatially separated nodes via optical photons into a quantum network will enable distributed quantum computing and long-range quantum communication. Initial experiments on trapped atoms and ions as well as defects in diamond have demonstrated entanglement between two nodes over several meters. To realize multi-node networks, additional quantum bit systems that store quantum states while new entanglement links are established are highly desirable. Such memories allow for entanglement distillation, purification and quantum repeater protocols that extend the size, speed and distance of the network. However, to be effective, the memory must be robust against the entanglement generation protocol, which typically must be repeated many times. Here we evaluate the prospects of using carbon nuclear spins in diamond as quantum memories that are compatible with quantum networks based on single nitrogen vacancy (NV) defects in diamond. We present a theoretical framework to describe the dephasing of the nuclear spins under repeated generation of NV spin-photon entanglement and show that quantum states can be stored during hundreds of repetitions using typical experimental coupling parameters. This result demonstrates that nuclear spins with weak hyperfine couplings are promising quantum memories for quantum networks.

Application of Optical Diagnosis to Aged Low-Voltage Cable Insulation in Nuclear Plants

NASA Astrophysics Data System (ADS)

Katagiri, Junichi; Takezawa, Yoshitaka; Shouji, Hiroshi

We have developed a novel non-destructive optical diagnosis technique for low-voltage cable insulations used in nuclear power plants. The key features of this diagnosis are the use of two wavelengths to measure the change in reflective absorbance (ΔAR), the use of polarized light to measure crystallinity and the use of element volatilizing to measure fluorescence. Chemical kinetics is used to predict the lifetimes of the cable insulations. When cable insulations darken and harden by time degradation, the ΔAR and depolarization parameters increase. This means that the cross-linking density in the cable insulations increases due to deterioration reactions. When the cross-linking density of insulation increases, its elasticity, corresponding to the material's life, increases. Similarly, as the crystallinity increases due to the change in the high-order structure of the insulating resin caused by irradiation, its elongation property decreases. The elongation property of insulation is one of the most important parameters that can be used to evaluate material lifetimes, because it relates to elasticity. The ΔAR correlated with the elongation property, and the correlation coefficient of an accelerated experiment using model pieces was over 0.9. Thus, we concluded that this optical diagnosis should be applied to evaluate the degradation of cable insulations used in nuclear power plants.

Fine structure and optical pumping of spins in individual semiconductor quantum dots

NASA Astrophysics Data System (ADS)

Bracker, Allan S.; Gammon, Daniel; Korenev, Vladimir L.

2008-11-01

We review spin properties of semiconductor quantum dots and their effect on optical spectra. Photoluminescence and other types of spectroscopy are used to probe neutral and charged excitons in individual quantum dots with high spectral and spatial resolution. Spectral fine structure and polarization reveal how quantum dot spins interact with each other and with their environment. By taking advantage of the selectivity of optical selection rules and spin relaxation, optical spin pumping of the ground state electron and nuclear spins is achieved. Through such mechanisms, light can be used to process spins for use as a carrier of information.

Radiation-Responsive Esculin-Derived Molecular Gels as Signal Enhancers for Optical Imaging.

PubMed

Silverman, Julian R; Zhang, Qize; Pramanik, Nabendu B; Samateh, Malick; Shaffer, Travis M; Sagiri, Sai Sateesh; Grimm, Jan; John, George

2017-12-13

Recent interest in detecting visible photons that emanate from interactions of ionizing radiation (IR) with matter has spurred the development of multifunctional materials that amplify the optical signal from radiotracers. Tailored stimuli-responsive systems may be paired with diagnostic radionuclides to improve surgical guidance and aid in detecting therapeutic radionuclides otherwise difficult to image with conventional nuclear medicine approaches. Because light emanating from these interactions is typically low in intensity and blue-weighted (i.e., greatly scattered and absorbed in vivo), it is imperative to increase or shift the photon flux for improved detection. To address this challenge, a gel that is both scintillating and fluorescent is used to enhance the optical photon output in image mapping for cancer imaging. Tailoring biobased materials to synthesize thixotropic thermoreversible hydrogels (a minimum gelation concentration of 0.12 wt %) offers image-aiding systems which are not only functional but also potentially economical, safe, and environmentally friendly. These robust gels (0.66 wt %, ∼900 Pa) respond predictably to different types of IRs including β- and γ-emitters, resulting in a doubling of the detectable photon flux from these emitters. The synthesis and formulation of such a gel are explored with a focus on its physicochemical and mechanical properties, before being utilized to enhance the visible photon flux from a panel of radionuclides as detected. The possibility of developing a topical cream of this gel makes this system an attractive potential alternative to current techniques, and the multifunctionality of the gelator may serve to inspire future next-generation materials.

Novel Scintillating Materials Based on Phenyl-Polysiloxane for Neutron Detection and Monitoring

NASA Astrophysics Data System (ADS)

Degerlier, M.; Carturan, S.; Gramegna, F.; Marchi, T.; Palma, M. Dalla; Cinausero, M.; Maggioni, G.; Quaranta, A.; Collazuol, G.; Bermudez, J.

Neutron detectors are extensively used at many nuclear research facilities across Europe. Their application range covers many topics in basic and applied nuclear research: in nuclear structure and reaction dynamics (reaction reconstruction and decay studies); in nuclear astrophysics (neutron emission probabilities); in nuclear technology (nuclear data measurements and in-core/off-core monitors); in nuclear medicine (radiation monitors, dosimeters); in materials science (neutron imaging techniques); in homeland security applications (fissile materials investigation and cargo inspection). Liquid scintillators, widely used at present, have however some drawbacks given by toxicity, flammability, volatility and sensitivity to oxygen that limit their duration and quality. Even plastic scintillators are not satisfactory because they have low radiation hardness and low thermal stability. Moreover organic solvents may affect their optical properties due to crazing. In order to overcome these problems, phenyl-polysiloxane based scintillators have been recently developed at Legnaro National Laboratory. This new solution showed very good chemical and thermal stability and high radiation hardness. The results on the different samples performance will be presented, paying special attention to a characterization comparison between synthesized phenyl containing polysiloxane resins where a Pt catalyst has been used and a scintillating material obtained by condensation reaction, where tin based compounds are used as catalysts. Different structural arrangements as a result of different substituents on the main chain have been investigated by High Resolution X-Ray Diffraction, while the effect of improved optical transmittance on the scintillation yield has been elucidated by a combination of excitation/fluorescence measurements and scintillation yield under exposure to alpha and γ-rays.

Optical gamma thermometer

DOEpatents

Koster, Glen Peter; Xia, Hua; Lee, Boon Kwee

2013-08-06

An optical gamma thermometer includes a metal mass having a temperature proportional to a gamma flux within a core of a nuclear reactor, and an optical fiber cable for measuring the temperature of the heated metal mass. The temperature of the heated mass may be measured by using one or more fiber grating structures and/or by using scattering techniques, such as Raman, Brillouin, and the like. The optical gamma thermometer may be used in conjunction with a conventional reactor heat balance to calibrate the local power range monitors over their useful in-service life. The optical gamma thermometer occupies much less space within the in-core instrument tube and costs much less than the conventional gamma thermometer.

Atlas of Atomic Spectral Lines of Neptunium Emitted by Inductively Coupled Plasma

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

DeKalb, E.L. and Edelson, M. C.

1987-08-01

Optical emission spectra from high-purity Np-237 were generated with a glovebox-enclosed inductively coupled plasma (ICP) source. Spectra covering the 230-700 nm wavelength range are presented along with general commentary on the methodology used in collecting the data. The Ames Laboratory Nuclear Safeguards and Security Program has been charged with the task of developing optical spectroscopic methods to analyze the composition of spent nuclear fuels. Such materials are highly radioactive even after prolonged 'cooling' and are chemically complex. Neptunium (Np) is a highly toxic by-product of nuclear power generation and is found, in low abundance, in spent nuclear fuels. This atlasmore » of the optical emission spectrum of Np, as produced by an inductively coupled plasma (ICP) spectroscopic source, is part of a general survey of the ICP emission spectra of the actinide elements. The ICP emission spectrum of the actinides originates almost exclusively from the electronic relaxation of excited, singly ionized species. Spectral data on the Np ion emission spectrum (i.e., the Np II spectrum) have been reported by Tomkins and Fred [1] and Haaland [2]. Tomkins and Fred excited the Np II spectrum with a Cu spark discharge and identified 114 Np lines in the 265.5 - 436.3 nm spectral range. Haaland, who corrected some spectral line misidentifications in the work of Tomkins and Fred, utilized an enclosed Au spark discharge to excite the Np II spectrum and reported 203 Np lines within the 265.4 - 461.0 nm wavelength range.« less

Frontiers of Physics 1998, Proceedings of the Intl Mtg

NASA Astrophysics Data System (ADS)

Chia, S. P.; Bradley, D. A.

The Table of Contents for the book is as follows: * FOREWORD * PLENARY SESSIONS * Progress of RFQ and superconducting accelerators in China * Dual Ginzburg-Landau theory and quark nuclear physics * Study of solid surfaces on a atomic scale * QCD phase transition in the laboratory and in the early universe * X-ray studies of magnetism: the synchrotron revolution * On the possibility of a gamma-laser: photon emission by a charged particle channeling in a acoustically bent crystal * Frontiers in ultrafast laser science * Inductively coupled RF discharges * Asymmetries of sea quark distributions in baryons * High energy limit of photon-atom interactions: example of double ionization of He by photoabsorption * Excitation of nuclear levels in atomic transitions * PARALLEL SESSIONS * Condensed Matter Physics * A variational approach to many-particle systems * Path-integral approach to band tail density of states in heavily doped semiconductors * Study of vibrational spectra of nanocrystalline silicon by Raman scattering and photoluminescence spectroscopy * Derivation of nonlinear magnetic susceptibility tensors for a ferromagnet * High hard magnetic properties of Sr hexagonal ferrite substituted by La * Elastic anomalies in superconducting and non-superconducting tl-based compounds * Theoretical calculation of the variation of interface parameter, S with the band gap of the ionic insulator * Stationary waves in nonlinear crystal lattices * Quantum field theory, non-linear optics and magnetic phase transitions * Annealing effects on optical and electrical properties of hydrogenated amorphous silicon film * Effect of composition, sintering and grain size on the physical properties of cullet-mica ceramics * Optical characterisation of thin metal film using surface plasmons resonance * A look at nonlinear susceptibility coefficients of ferroelectrics in the far infrared * Elastic behaviour of lead zinc phosphate glasses * Characterization of Gd doped Y-Ba-Cu-O superconductor by ac-susceptibility method * Role of Pb substitution in the formation of single phase Bi-Sr-Ca-Cu-O superconductors * Magnetic and electrical properties of Bi1.6Pb0.4Sr2Ca2(Su1-xSnx)3Oδ superconducting ceramics * Synchrotron Light Sources * Synchrotron radiation activities at KEK * From archaeology to zoology: the diversity in experimentation at a versatile synchrotron radiation beamline * Beijing light source: the Beijing synchrotron radiation facility * Present status of Pohang light source * Present status of synchrotron radiation research in Thailand - the Siam Photon project * Present status of Taiwan light source * Plasma Physics & Technology * Results of the UNU/ICTP PFF network * Dense plasma focus and plasma processing of materials * Carbon nitride thin films research at Nanyang Technological University * High voltage shock-wave and soliton generation * Film deposition of TiN on metal substrates using a plasma sputter-type Ion source * Investigation of the performance of a 2.3 kJ plasma focus device * Dense plasma sequential focus device * Time profile of the neutron emission from a small plasma focus * Characterization of a plasma ozonizer and its application * 0.2 micron lithography using a powerful plasma focus soft X-ray source * Transverse profile analysis of a plasma beam in a plasma-sputter-type ion source * Ion dynamics in the sheath in multicomponent plasma with negative ions * Atomic Physics * New generation positron-atom scattering theories * Electron impact on excited helium * An ab initio optical potential treatment of positron scattering by H atom * Optical potential models for positron scattering from bound atoms * Particle Physics * Superconducting pairing of quarks in QCD * Absorptive contributions of the electroweak penguins * Results on atmospheric neutrinos from super-Kamiokande - evidence for νμ oscillations - * Fermion quantum field theory in black-hole spacetimes * Calculation of the Higgs-Penguin vertex function * Torsion and the Adler-Bell-Jackiw anomaly * Cosmological constant in de-Sitter spacetime * Quantum supergroups and noncommutative superspaces * Production of dissimilar quark-antiquark pairs from e+e- collision * Flavour-changing two-gluon penguin vertex * Laser Physics * Photon-gated persistent spectral hole burning * Propagation of finite electromagnetic waves in the generalised eikonal formalism * Digital recording and reconstruction of holograms * A two-stage Blumlein circuit for nitrogen laser * Some characteristics of thermally induced fracture of glass under non-uniform radiant heating * Digital holography and application to laser metrology * Investigation of laser-etching quality on film substrate using copper vapour and argon ion lasers * Studies of side pin electrode configuration in a fast-axial-flow CW CO2 laser * Laser trimming of thick film resistors * Damage performed by a Q-switched infrared laser * Applied Physics * Wind driven circulation of the South China Sea * An efficient analysis of temporal pulse propagation through a turbid medium using a Monte Carlo protocol * Pulsed photothermal radiometry in lateral geometry * Changes in dielectric constant and loss factor of various cooking oils * Polarization conversion through the excitation of electromagnetic modes on grating and grating waveguide * Vibration monitoring of a rotary vacuum pump at various levels of vacuum and their remedial techniques * El Nino southern oscillation (ENSO) and outgoing longwave radiation (OLR) * Experimental evidence for variation in electronic chemical potential with size of metal substrate in a reversible electrode * Radiation & Nuclear Physics * Effect of soil type on environmental terrestrial gamma radiation dose in Johor State, Malaysia * Uptake and tissue distribution of 137Cs by Magur fish (clarius batrachus) * Diurnal and spacial variation of radon concentration in Malaysian houses * Tests of thermoluminescence dating at Gua Tok Long archaeological site * Alpha spectra from samples of alluvial material contaminated by oxides of thorium * Effect of radiation on thermoluminescence and transmission characteristics of optical fibres * Photon backscatter factors for ISO reference radiations * Discriminant analysis of breast tissue elemental concentration data with determination limits * Determination of air kerma and absorbed dose to water calibration factors of a chamber in a 60Co gamma ray beam * Beam size measurement of a 60Co teletherapy unit at a dosimeter calibration position * Modern neutron skyshine response functions for integral line-beam and conical-beam methods * On the normalization constants associated with the nuclear bound-state wavefunctions * Atomic and nuclear cluster effects in deuterium cluster ion implantation on solids * Optical Fibres * Research in optical fibres devices at Telekom Malaysia photonics laboratory * Erbium doped fiber lasers for optical communications * Characteristics evolution in erbium-doped fibre amplifiers * Development of optical fiber preform fabrication facility at Telekom Malaysia * Multiple signal generation in a BEFL system * Fibre Bragg gratings for optical communication: fabrication and characterisation * Optimization of the reflectivity in Er3+/Yb3+ co-doped fiber laser design for maximum output power * Back reflection study on a fiber laser system * Mathematical and Computational Physics * Simplifying complexity * Asymptotic behaviour of Burgers equation with noisy boundary condition * Kinematical symmetries on punctured sphere * Cellular automata studies of the prisoner's dilemma * Astrophysics * Gravitational wave detection in the laboratory * Eclipsing binary stars in the EROS catalogue * Measurement of seismic noise at the site of Tianyin-100 in UTM * Using thinner suspension wire to reduce thermal noise in Tianyin-100 * Energy losses of solar neutrinos using the standard solar model * Participant List

Nuclear quadrupole moment-induced Cotton-Mouton effect in molecules

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

Fu, Li-juan, E-mail: lijuan.fu@oulu.fi, E-mail: juha.vaara@iki.fi; Vaara, Juha, E-mail: lijuan.fu@oulu.fi, E-mail: juha.vaara@iki.fi

Nuclear magneto-optic effects could make important contributions to novel, high-sensitivity, and high-resolution spectroscopic and imaging methods that provide nuclear site-specific structural and dynamic information on molecular and materials systems. Here we present a first-principles electronic structure formulation of nuclear quadrupole moment-induced Cotton-Mouton effect in terms of response theory, as well as ab initio and density-functional theory calculations of this phenomenon for a series of molecular liquids: H{sub 2}O, CH{sub 3}NO{sub 2}, CH{sub 3}CH{sub 2}OH, C{sub 6}H{sub 6}, C{sub 6}H{sub 12} (cyclohexane), HI, XeF{sub 2}, WF{sub 5}Cl, and Pt(C{sub 2}dtp){sub 2}. The roles of basis-set convergence, electron correlation, and relativistic effectsmore » are discussed. The estimated order of magnitude of the overall ellipticities induced to linearly polarized light is 10{sup −3}–10{sup −7} rad/(M cm) for fully spin polarized nuclei. The cases with the largest presently obtained ellipticities should be detectable with modern instrumentation in the Voigt magneto-optic setup, particularly for the heavy nuclei.« less

Protection against UV and X-ray cataracts using dynamic light scattering

NASA Technical Reports Server (NTRS)

Giblin, Frank J.

2005-01-01

Static and dynamic light scattering (SLS and DLS) analysis was used to investigate the aggregation of lens proteins in a hyperbaric oxygen (HBO)/guinea pig in vivo model for nuclear cataract. Nuclear cataract, an opacity which occurs in the center of the lens, is a major type of human maturity-onset cataract for which the cause is not well-understood. HBO is commonly used in major hospitals for treating complications such as poor wound healing due to impaired blood circulation. It is known that treatment of human patients with HBO for extended periods of time can produce nuclear cataract. Guinea pigs, initially 18 months old, were treated with HBO (2.5 atm of 100% O2 for 2.5 hr) 3x per week for 7 months to increase tie level of lens nuclear light scattering. Age-matched animals were used for controls. The eyes of the animals were analyzed in vivo using an integrated static and DLS fiber optic probe in collaboration with the NASA group. DLS in vivo was used to measure the size of lens proteins at 50 different locations across the optical axis of the guinea pig lens.

A Compact Fiber Optic Eye Diagnostic System

NASA Technical Reports Server (NTRS)

Ansari, Rafat R.; Suh, Kwang I.; Dubin, Stephen; Dellavecchia, Michael A.

1995-01-01

A new fiber optic probe developed for determining transport properties of sub-micron particles in fluid experiments in a microgravity environment has been applied to study different parts of an eye. The probe positioned in front of an eye, delivers a low power (approximately few microW) light from a laser diode into the eye and guides the light which is back scattered by different components (aqueous humor, lens, and vitreous humor) of the eye through a receiving optical fiber to a photo detector. The probe provides rapid determination of macromolecular diffusivities and their respective size distributions in the eye lens and the gel-like materials in the vitreous humor. In a clinical setting, the probe can be mounted on a standard slit-lamp apparatus simply using a Hruby lens holder. The capability of detecting cataracts, both nuclear and cortical, in their early stages of formation, in a non invasive and quantitative fashion, has the potential in patient monitoring and in developing and testing new drugs or diet therapies to 'dissolve' or slow down the cataract formation before the surgery becomes necessary. The ability to detect biochemical and macromolecular changes in the vitreous structure can be very useful in identifying certain diseases of the posterior chamber and their complications, e.g., posterior vitreous detachment and diabetic retinopathy.

A Compact Fiber Optic Eye Diagnostics System

NASA Technical Reports Server (NTRS)

Ansari, Rafat R.; Suh, Kwang I.; DellaVecchia, Michael A.; Dubin, Stephen; Zigler, J. Samuel, Jr.

1995-01-01

A new fiber optic probe development for determining transport properties of sub-micron particles in fluids experiments in a microgravity environment has been applied to study different parts of the eye. The probe positioned in front of an eye, delivers a low power (approximately a few mu W) light from a laser diode into the eye and guides the light which is back scattered by different components (aqueous humor, lens, and vitreous humor) of the eye through a receiving optical fiber to a photo detector. The probe provides rapid determination of macromolecular diffusivities and their respective size distributions in the eye lens and the gel-like material in the vitreous humor. For a clinical use, the probe is mounted on a standard slit-lamp apparatus simply using Hruby lens holder. The capability of detecting cataracts, both nuclear and cortical, in their early stages of formation, in a non invasive and quantitative fashion, has the potential in patient monitoring and in developing and testing new drugs or diet therapies to 'dissolve' or slow down the cataract formation before the surgery becomes necessary. The ability to detect biochemical and macromolecular changes in the vitreous structure can be very useful in identifying certain diseases of the posterior chamber and their complications, e.g., posterior vitreous detachment and diabetic retinopathy.

Ophthalmic Diagnostics Using a New Dynamic Light Scattering Fiber Optic Probe

NASA Technical Reports Server (NTRS)

Ansari, Rafat R.; Suh, Kwang I.; Dellavecchia, Michael A.; Dubin, Stephen

1995-01-01

A new fiber optic probe is developed to study different parts of the eye. The probe positioned in front of an eye, delivers a low power light from a laser diode into the eye and guides the light which is back scattered by different components (aqueous humor, lens, and vitreous humor) of the eye through a receiving optical fiber to a photo detector. The probe provides rapid determination of macromolecular diffusivities and their respective size distributions in the eye lens and the gel-like material in the vitreous humor. We report alpha-crystalline size distributions, as a function of penetration depth, inside the lens and hyaluronic acid molecular size distribution in the vitreous body. In a clinical setting, the probe can be mounted on a slit-lamp apparatus simply by using a H-ruby lens holder. The capability of detecting cataracts, both nuclear and peripheral, in their early stages of formation, in a non invasive and quantitative fashion, has the potential in patient monitoring and in developing and testing new drugs or diet therapies to 'dissolve' or slow down the cataract formation before surgery is necessary. The ability to detect biochemical and macromolecular changes in the vitreous structure can be very useful in identifying certain diseases of the posterior chamber, e.g., posterior vitreous detachment.

SO(3) "Nuclear Physics" with ultracold Gases

NASA Astrophysics Data System (ADS)

Rico, E.; Dalmonte, M.; Zoller, P.; Banerjee, D.; Bögli, M.; Stebler, P.; Wiese, U.-J.

2018-06-01

An ab initio calculation of nuclear physics from Quantum Chromodynamics (QCD), the fundamental SU(3) gauge theory of the strong interaction, remains an outstanding challenge. Here, we discuss the emergence of key elements of nuclear physics using an SO(3) lattice gauge theory as a toy model for QCD. We show that this model is accessible to state-of-the-art quantum simulation experiments with ultracold atoms in an optical lattice. First, we demonstrate that our model shares characteristic many-body features with QCD, such as the spontaneous breakdown of chiral symmetry, its restoration at finite baryon density, as well as the existence of few-body bound states. Then we show that in the one-dimensional case, the dynamics in the gauge invariant sector can be encoded as a spin S = 3/2 Heisenberg model, i.e., as quantum magnetism, which has a natural realization with bosonic mixtures in optical lattices, and thus sheds light on the connection between non-Abelian gauge theories and quantum magnetism.

[Morphological and functional characteristics of lymphocytes of mothers of children with Down syndrome].

PubMed

Novikov, V D; Valova, T A; Iasakova, N T; Belan, I B

2000-01-01

Nuclear chromatine of peripheral blood lymphocytes was studied in 13 women with children suffering from Down's syndrome using optic structural computer analysis. In 12 cases significant increase of nuclear roundness coefficient was determined. Deformation coefficient was determined for heterochromatine structures in 8 cases. Integral optic density of nuclear chromatine was significantly decreased in 12 women. This indicates the reduction of felgen-positive material due to deficiency of its compact fraction (in 11 cases). The activity of lymphocyte cytoplasmic lactate, alpha-glycerophosphate and succinate dehydrogenases (SDG) was studied morphocytochemically in 5 women who had children with the disease. High activity of mitochondrial SDG was determined in all cases which probably indicates disorders in lymphocyte energy state. This is one of the reasons for retention of risk pregnancy. Further research in this area may serve as a base for complete cytoanalysis in order to distinguish risk groups among women including primagravida for consequent determination of embryonal karyotype.

Temperature Resistant Fiber Bragg Gratings for On-Line and Structural Health Monitoring of the Next-Generation of Nuclear Reactors.

PubMed

Laffont, Guillaume; Cotillard, Romain; Roussel, Nicolas; Desmarchelier, Rudy; Rougeault, Stéphane

2018-06-02

The harsh environment associated with the next generation of nuclear reactors is a great challenge facing all new sensing technologies to be deployed for on-line monitoring purposes and for the implantation of SHM methods. Sensors able to resist sustained periods at very high temperatures continuously as is the case within sodium-cooled fast reactors require specific developments and evaluations. Among the diversity of optical fiber sensing technologies, temperature resistant fiber Bragg gratings are increasingly being considered for the instrumentation of future nuclear power plants, especially for components exposed to high temperature and high radiation levels. Research programs are supporting the developments of optical fiber sensors under mixed high temperature and radiative environments leading to significant increase in term of maturity. This paper details the development of temperature-resistant wavelength-multiplexed fiber Bragg gratings for temperature and strain measurements and their characterization for on-line monitoring into the liquid sodium used as a coolant for the next generation of fast reactors.

Alpha decay studies on Po isotopes using different versions of nuclear potentials

NASA Astrophysics Data System (ADS)

Santhosh, K. P.; Sukumaran, Indu

2017-12-01

The alpha decays from 186-224Po isotopes have been studied using 25 different versions of nuclear potentials so as to select a suitable nuclear potential for alpha decay studies. The computed standard deviation of the calculated half-lives in comparison with the experimental data suggested that proximity 2003-I is the apt form of nuclear potential for alpha decay studies as it possesses the least standard deviation, σ =0.620 . Among the different proximity potentials, proximity 1966 ( σ =0.630 and proximity 1977 ( σ =0.636 , are also found to work well in alpha decay studies with low deviation. Among other versions of nuclear potentials (other than proximity potentials), Bass 1980 is suggested to be a significant form of nuclear potential because of its good predictive power. However, while the other forms of potentials are able to reproduce the experimental data to some extent, these potentials cannot be considered as apposite potentials for alpha decay studies in their present form. Since the experimental correlation of the models is noticed to be satisfying, the alpha decay half-lives of certain Po isotopes that are not detected experimentally yet have been predicted.

Effects of chiral three-nucleon forces on 4He-nucleus scattering in a wide range of incident energies

NASA Astrophysics Data System (ADS)

Toyokawa, Masakazu; Yahiro, Masanobu; Matsumoto, Takuma; Kohno, Michio

2018-02-01

An important current subject is to clarify the properties of chiral three-nucleon forces (3NFs) not only in nuclear matter but also in scattering between finite-size nuclei. Particularly for elastic scattering, this study has just started and the properties are not understood for a wide range of incident energies (E_in). We investigate basic properties of chiral 3NFs in nuclear matter with positive energies by using the Brueckner-Hartree-Fock method with chiral two-nucleon forces at N3LO and 3NFs at NNLO, and analyze the effects of chiral 3NFs on 4He elastic scattering from targets ^{208}Pb, ^{58}Ni, and ^{40}Ca over a wide range of 30 ≲ E_in/A_P ≲ 200 MeV by using the g-matrix folding model, where A_P is the mass number of the projectile. In symmetric nuclear matter with positive energies, chiral 3NFs make the single-particle potential less attractive and more absorptive. The effects mainly come from the Fujita-Miyazawa 2π-exchange 3NF and become slightly larger as E_in increases. These effects persist in the optical potentials of 4He scattering. As for the differential cross sections of 4He scattering, chiral-3NF effects are large for E_in/A_P ≳ 60 MeV and improve the agreement of the theoretical results with the measured ones. Particularly for E_in/A_P ≳ 100 MeV, the folding model reproduces measured differential cross sections pretty well. Cutoff (Λ) dependence is investigated for both nuclear matter and 4He scattering by considering two cases of Λ=450 and 550 MeV. The uncertainty coming from the dependence is smaller than chiral-3NF effects even at E_in/A_P=175 MeV.

Environmental Detection of Clandestine Nuclear Weapon Programs

NASA Astrophysics Data System (ADS)

Kemp, R. Scott

2016-06-01

Environmental sensing of nuclear activities has the potential to detect nuclear weapon programs at early stages, deter nuclear proliferation, and help verify nuclear accords. However, no robust system of detection has been deployed to date. This can be variously attributed to high costs, technical limitations in detector technology, simple countermeasures, and uncertainty about the magnitude or behavior of potential signals. In this article, current capabilities and promising opportunities are reviewed. Systematic research in a variety of areas could improve prospects for detecting covert nuclear programs, although the potential for countermeasures suggests long-term verification of nuclear agreements will need to rely on methods other than environmental sensing.

Nuclear Technology. Course 27: Metrology. Module 27-4, Angle Measurement Instruments, Optical Projections and Surface Texture Gages.

ERIC Educational Resources Information Center

Selleck, Ben; Espy, John

This fourth in a series of eight modules for a course titled Metrology describes the universal bevel protractor and the sine bar, the engineering microscope and optical projector, and several types of surface texture gages. The module follows a typical format that includes the following sections: (1) introduction, (2) module prerequisites, (3)…

Integrated Structural and Cable Connector

NASA Technical Reports Server (NTRS)

Totah, R. S.

1982-01-01

Ball-and-socket coupling includes fiber-optic cable. Three steps couple two parts of fiber-optic cable: ball is inserted into socket; cone is released in, and cable moves toward plug. Sleeve is pulled to end of its travel and cable and plug are mated. Device is a quick-connect/disconnect coupling that has application in hazardous environments, such as space, undersea and nuclear installations.

Persistent Optical Nuclear Spin Narrowing in a Singly Charged InAs Quantum Dot

DTIC Science & Technology

2012-02-01

explained in terms of an anisotropic hyperfine coupling between the hole spin and the nuclear spins. © 2012 Optical Society of America OCIS codes: 300.6250...February 2012 / J. Opt. Soc. Am. B A121 where γs (γt) is the spin (trion) dephasing rate, χ is half the pump Rabi frequency ΩR (ΩR # μEℏ , where μ is...probe ab- sorption at the dark state dip (αdip) and the Rabi sideband (αpeak): αdip # α0 χ2γs & γt$γ2s% χ4 & 2χ2γtγs & γ2t γ2s ; (11) αpeak # α0 χ2γs

A compact spin-exchange optical pumping system for 3He polarization based on a solenoid coil, a VBG laser diode, and a cosine theta RF coil

NASA Astrophysics Data System (ADS)

Lee, Sungman; Kim, Jongyul; Moon, Myung Kook; Lee, Kye Hong; Lee, Seung Wook; Ino, Takashi; Skoy, Vadim R.; Lee, Manwoo; Kim, Guinyun

2013-02-01

For use as a neutron spin polarizer or analyzer in the neutron beam lines of the HANARO (High-flux Advanced Neutron Application ReactOr) nuclear research reactor, a 3He polarizer was designed based on both a compact solenoid coil and a VBG (volume Bragg grating) diode laser with a narrow spectral linewidth of 25 GHz. The nuclear magnetic resonance (NMR) signal was measured and analyzed using both a built-in cosine radio-frequency (RF) coil and a pick-up coil. Using a neutron transmission measurement, we estimated the polarization ratio of the 3He cell as 18% for an optical pumping time of 8 hours.

Precise Measurement of Parity Nonconserving Optical Rotation in Atomic Thallium

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

Edwards, N.H.; Phipp, S.J.; Baird, P.E.G.

1995-04-03

We report a new measurement of parity nonconserving (PNC) optical rotation on the 6{ital p}{sub 1/2}-6{ital p}{sub 3/2} transition in atomic thallium near 1283 nm. The result expressed in terms of the quantity R=Im{l_brace}{ital E}1{sup PNC}/{ital M}1{r_brace} is {minus}(15.68{plus_minus}0.45){times}10{sup {minus}8}, and is consistent with current calculations based on the standard model. In addition, limits have been set on the much smaller nuclear spin-dependent rotation amplitude at R{sub {ital S}}=(0.04{plus_minus}0.20){times}10{sup {minus}8}; this is consistent with theoretical estimates which include a nuclear anapole contribution.

Looking Down Through the Clouds – Optical Attenuation through Real-Time Clouds

NASA Astrophysics Data System (ADS)

Burley, J.; Lazarewicz, A.; Dean, D.; Heath, N.

Detecting and identifying nuclear explosions in the atmosphere and on the surface of the Earth is critical for the Air Force Technical Applications Center (AFTAC) treaty monitoring mission. Optical signals, from surface or atmospheric nuclear explosions detected by satellite sensors, are attenuated by the atmosphere and clouds. Clouds present a particularly complex challenge as they cover up to seventy percent of the earth's surface. Moreover, their highly variable and diverse nature requires physics-based modeling. Determining the attenuation for each optical ray-path is uniquely dependent on the source geolocation, the specific optical transmission characteristics along that ray path, and sensor detection capabilities. This research details a collaborative AFTAC and AFIT effort to fuse worldwide weather data, from a variety of sources, to provide near-real-time profiles of atmospheric and cloud conditions and the resulting radiative transfer analysis for virtually any wavelength(s) of interest from source to satellite. AFIT has developed a means to model global clouds using the U.S. Air Force’s World Wide Merged Cloud Analysis (WWMCA) cloud data in a new toolset that enables radiance calculations through clouds from UV to RF wavelengths.

Development of a fiber-guided laser ultrasonic system resilient to high temperature and gamma radiation for nuclear power plant pipe monitoring

NASA Astrophysics Data System (ADS)

Yang, Jinyeol; Lee, Hyeonseok; Lim, Hyung Jin; Kim, Nakhyeon; Yeo, Hwasoo; Sohn, Hoon

2013-08-01

This study develops an embeddable optical fiber-guided laser ultrasonic system for structural health monitoring (SHM) of pipelines exposed to high temperature and gamma radiation inside nuclear power plants (NPPs). Recently, noncontact laser ultrasonics is gaining popularity among the SHM community because of its advantageous characteristics such as (a) scanning capability, (b) immunity against electromagnetic interference (EMI) and (c) applicability to high-temperature surfaces. However, its application to NPP pipelines has been hampered because pipes inside NPPs are often covered by insulators and/or target surfaces are not easily accessible. To overcome this problem, this study designs embeddable optical fibers and fixtures so that laser beams used for ultrasonic inspection can be transmitted between the laser sources and the target pipe. For guided-wave generation, an Nd:Yag pulsed laser coupled with an optical fiber is used. A high-power pulsed laser beam is guided through the optical fiber onto a target structure. Based on the principle of laser interferometry, the corresponding response is measured using a different type of laser beam guided by another optical fiber. All devices are especially designed to sustain high temperature and gamma radiation. The robustness/resilience of the proposed measurement system installed on a stainless steel pipe specimen has been experimentally verified by exposing the specimen to high temperature of up to 350 °C and optical fibers to gamma radiation of up to 125 kGy (20 kGy h-1).

Neutron scattering from 208Pb at 30.4 and 40.0 MeV and isospin dependence of the nucleon optical potential

NASA Astrophysics Data System (ADS)

Devito, R. P.; Khoa, Dao T.; Austin, Sam M.; Berg, U. E. P.; Loc, Bui Minh

2012-02-01

Background: Analysis of data involving nuclei far from stability often requires the optical potential (OP) for neutron scattering. Because neutron data are seldom available, whereas proton scattering data are more abundant, it is useful to have estimates of the difference of the neutron and proton optical potentials. This information is contained in the isospin dependence of the nucleon OP. Here we attempt to provide it for the nucleon-208Pb system.Purpose: The goal of this paper is to obtain accurate n+208Pb scattering data and use it, together with existing p+208Pb and 208Pb(p,n)208BiIAS* data, to obtain an accurate estimate of the isospin dependence of the nucleon OP at energies in the 30-60-MeV range.Method: Cross sections for n+208Pb scattering were measured at 30.4 and 40.0 MeV, with a typical relative (normalization) accuracy of 2-4% (3%). An angular range of 15∘ to 130∘ was covered using the beam-swinger time-of-flight system at Michigan State University. These data were analyzed by a consistent optical-model study of the neutron data and of elastic p+208Pb scattering at 45 and 54 MeV. These results were combined with a coupled-channel analysis of the 208Pb(p,n) reaction at 45 MeV, exciting the 0+ isobaric analog state (IAS) in 208Bi.Results: The new data and analysis give an accurate estimate of the isospin impurity of the nucleon-208Pb OP at 30.4 MeV caused by the Coulomb correction to the proton OP. The corrections to the real proton OP given by the CH89 global systematics were found to be only a few percent, whereas for the imaginary potential it was greater than 20% at the nuclear surface. On the basis of the analysis of the measured elastic n+208Pb data at 40 MeV, a Coulomb correction of similar strength and shape was also predicted for the p+208Pb OP at energies around 54 MeV.Conclusions: Accurate neutron scattering data can be used in combination with proton scattering data and (p,n) charge exchange data leading to the IAS to obtain reliable estimates of the isospin impurity of the nucleon OP.

Optical properties of metal-dielectric based epsilon near zero metamaterials

NASA Astrophysics Data System (ADS)

Subramania, Ganapathi; Fischer, Arthur; Luk, Ting

2014-03-01

Epsilon(ɛ) near zero(ENZ) materials are metamaterials where the effective dielectric constant(ɛ) is close to zero for a range of wavelengths resulting in zero effective displacement field (D = ɛE) and displacement current. ENZ structures are of great interest in many application areas such as optical nanocircuits, supercoupling, cloaking, emission enhancement etc. Effective ENZ behavior has been demonstrated using cut-off frequency region in a metallic waveguide where the modal index vanishes. Here we demonstrate the fabrication of ENZ metamaterials operating at visible wavelengths (λ ~ 640nm) using an effective medium approach based on a metal-dielectric composites(App. Phys. Let.,101,241107(2012)) that can act as ``bulk'' ENZ material. The structure consists of a multilayer stack composite of alternating nanoscale thickness layers of Ag and TiO2. Optical spectroscopy shows transmission and absorption response is consistent with ENZ behavior and matches well with simulations. We will discuss the criteria necessary in the design and practical implementation of the composite that better approximates a homogenous effective medium including techniques to minimize the effect of optical losses to boost transmission. The potential for hosting gain media in the gratings to address losses and emission control will be 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. DOE's National Nuclear Security Administration under contract DE-AC04-94AL85000.

The role of science in treaty verification.

PubMed

Gavron, Avigdor

2005-01-01

Technologically advanced nations are currently applying more science to treaty verification than ever before. Satellites gather a multitude of information relating to proliferation concerns using thermal imaging analysis, nuclear radiation measurements, and optical and radio frequency signals detection. Ground stations gather complementary signals such as seismic events and radioactive emissions. Export controls in many countries attempt to intercept materials and technical means that could be used for nuclear proliferation. Nevertheless, we have witnessed a plethora of nuclear proliferation episodes, that were undetected (or were belatedly detected) by these technologies--the Indian nuclear tests in 1998, the Libyan nuclear buildup, the Iranian enrichment program and the North Korea nuclear weapons program are some prime examples. In this talk, we will discuss some of the technologies used for proliferation detection. In particular, we will note some of the issues relating to nuclear materials control agreements that epitomize political difficulties as they impact the implementation of science and technology.

The tethering of chromatin to the nuclear envelope supports nuclear mechanics

PubMed Central

Schreiner, Sarah M.; Koo, Peter K.; Zhao, Yao; Mochrie, Simon G. J.; King, Megan C.

2015-01-01

The nuclear lamina is thought to be the primary mechanical defence of the nucleus. However, the lamina is integrated within a network of lipids, proteins and chromatin; the interdependence of this network poses a challenge to defining the individual mechanical contributions of these components. Here, we isolate the role of chromatin in nuclear mechanics by using a system lacking lamins. Using novel imaging analyses, we observe that untethering chromatin from the inner nuclear membrane results in highly deformable nuclei in vivo, particularly in response to cytoskeletal forces. Using optical tweezers, we find that isolated nuclei lacking inner nuclear membrane tethers are less stiff than wild-type nuclei and exhibit increased chromatin flow, particularly in frequency ranges that recapitulate the kinetics of cytoskeletal dynamics. We suggest that modulating chromatin flow can define both transient and long-lived changes in nuclear shape that are biologically important and may be altered in disease. PMID:26074052

Vorinostat differentially alters 3D nuclear structure of cancer and non-cancerous esophageal cells.

PubMed

Nandakumar, Vivek; Hansen, Nanna; Glenn, Honor L; Han, Jessica H; Helland, Stephanie; Hernandez, Kathryn; Senechal, Patti; Johnson, Roger H; Bussey, Kimberly J; Meldrum, Deirdre R

2016-08-09

The histone deacetylase (HDAC) inhibitor vorinostat has received significant attention in recent years as an 'epigenetic' drug used to treat solid tumors. However, its mechanisms of action are not entirely understood, particularly with regard to its interaction with the aberrations in 3D nuclear structure that accompany neoplastic progression. We investigated the impact of vorinostat on human esophageal epithelial cell lines derived from normal, metaplastic (pre-cancerous), and malignant tissue. Using a combination of novel optical computed tomography (CT)-based quantitative 3D absorption microscopy and conventional confocal fluorescence microscopy, we show that subjecting malignant cells to vorinostat preferentially alters their 3D nuclear architecture relative to non-cancerous cells. Optical CT (cell CT) imaging of fixed single cells showed that drug-treated cancer cells exhibit significant alterations in nuclear morphometry. Confocal microscopy revealed that vorinostat caused changes in the distribution of H3K9ac-marked euchromatin and H3K9me3-marked constitutive heterochromatin. Additionally, 3D immuno-FISH showed that drug-induced expression of the DNA repair gene MGMT was accompanied by spatial relocation toward the center of the nucleus in the nuclei of metaplastic but not in non-neoplastic cells. Our data suggest that vorinostat's differential modulation of 3D nuclear architecture in normal and abnormal cells could play a functional role in its anti-cancer action.

Thinking About Preventing Nuclear War.

ERIC Educational Resources Information Center

Ground Zero, Washington, DC.

Potential paths to nuclear war and the available means of prevention of nuclear war are discussed. Presented is a detailed description of six nuclear war scenarios, and brief examples of types of potential deterrents to nuclear war (firebreaks) which are relevant for each. To be effective, the right combination of firebreaks must be used, the…

Dose Deposition Profiles in Untreated Brick Material

DOE PAGES

O'Mara, Ryan; Hayes, Robert

2018-04-01

In nuclear forensics or accident dosimetry, building materials such as bricks can be used to retrospectively determine radiation fields using thermoluminescence and/or optically stimu-lated luminescence. A major problem with brick material is that significant chemical processing is generally necessary to isolate the quartz from the brick. In this study, a simplified treatment process has been tested in an effort to lessen the processing burden for retrospective dosimetry studies. It was found that by using thermoluminescence responses, the dose deposition profile of a brick sample could be reconstructed without any chemical treat-ment. This method was tested by estimating the gamma-ray ener-giesmore » of an 241Am source from the dose deposition in a brick. The results demonstrated the ability to retrospectively measure the source energy with an overall energy resolution of approximately 6 keV. This technique has the potential to greatly expedite dose re-constructions in the wake of nuclear accidents or for any related application where doses of interest are large compared to overall process system noise.« less

Dose Deposition Profiles in Untreated Brick Material

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

O'Mara, Ryan; Hayes, Robert

In nuclear forensics or accident dosimetry, building materials such as bricks can be used to retrospectively determine radiation fields using thermoluminescence and/or optically stimu-lated luminescence. A major problem with brick material is that significant chemical processing is generally necessary to isolate the quartz from the brick. In this study, a simplified treatment process has been tested in an effort to lessen the processing burden for retrospective dosimetry studies. It was found that by using thermoluminescence responses, the dose deposition profile of a brick sample could be reconstructed without any chemical treat-ment. This method was tested by estimating the gamma-ray ener-giesmore » of an 241Am source from the dose deposition in a brick. The results demonstrated the ability to retrospectively measure the source energy with an overall energy resolution of approximately 6 keV. This technique has the potential to greatly expedite dose re-constructions in the wake of nuclear accidents or for any related application where doses of interest are large compared to overall process system noise.« less

Systematic study of proton capture reactions in medium-mass nuclei relevant to the p process: The case of 103Rh and In,115113

NASA Astrophysics Data System (ADS)

Harissopulos, S.; Spyrou, A.; Foteinou, V.; Axiotis, M.; Provatas, G.; Demetriou, P.

2016-02-01

The cross sections of the 103Rh(p ,γ )104Pd and the In,115113(p ,γ )Sn,116114 reactions have been determined from γ angular distribution measurements carried out at beam energies from 2 to 3.5 MeV. An array of four highly efficient HPGe detectors all shielded with BGO crystals for Compton background suppression was used. Astrophysical S factors and reaction rates were deduced from the measured cross sections. Statistical model calculations were performed using the Hauser-Feshbach (HF) code TALYS and were compared with the new data. A good agreement between theory and experiment was found. In addition, the effect of different combinations of the nuclear input parameters entering the HF calculations on the ground-state reaction rates was investigated. It was found that these rates differ by a factor 3 at the most, being thus within the average discrepancies observed between calculated p -nuclei abundances and observations, if certain combinations of optical model potentials, nuclear level densities, and γ -ray strength functions are used.

Recent Trends in Antibody-based Oncologic Imaging

PubMed Central

Kaur, Sukhwinder; Venktaraman, Ganesh; Jain, Maneesh; Senapati, Shantibhusan; Garg, Pradeep K.; Batra, Surinder K.

2011-01-01

Antibodies, with their unmatched ability for selective binding to any target, are considered as potentially the most specific probes for imaging. Their clinical utility, however, has been limited chiefly due to their slow clearance from the circulation, longer retention in non-targeted tissues and the extensive optimization required for each antibody-tracer. The development of newer contrast agents, combined with improved conjugation strategies and novel engineered forms of antibodies (diabodies, minibodies, single chain variable fragments, and nanobodies), have triggered a new wave of antibody-based imaging approaches. Apart from their conventional use with nuclear imaging probes, antibodies and their modified forms are increasingly being employed with non-radioisotopic contrast agents (MRI and ultrasound) as well as newer imaging modalities, such as quantum dots, near infra red (NIR) probes, nanoshells and surface enhanced Raman spectroscopy (SERS). The review article provides new developments in the usage of antibodies and their modified forms in conjunction with probes of various imaging modalities such as nuclear imaging, optical imaging, ultrasound, MRI, SERS and nanoshells in preclinical and clinical studies on the diagnosis, prognosis and therapeutic responses of cancer. PMID:22104729

Large volume multiple-path nuclear pumped laser

NASA Technical Reports Server (NTRS)

Hohl, F.; Deyoung, R. J. (Inventor)

1981-01-01

Large volumes of gas are excited by using internal high reflectance mirrors that are arranged so that the optical path crosses back and forth through the excited gaseous medium. By adjusting the external dielectric mirrors of the laser, the number of paths through the laser cavity can be varied. Output powers were obtained that are substantially higher than the output powers of previous nuclear laser systems.

A new Cu–cysteamine complex: structure and optical properties

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

Ma, Lun; Chen, Wei; Schatte, Gabriele

2014-06-07

Here we report the structure and optical properties of a new Cu–cysteamine complex (Cu–Cy) with a formula of Cu3Cl(SR)2 (R ¼ CH2CH2NH2). This Cu–Cy has a different structure from a previous Cu–Cy complex, in which both thio and amine groups from cysteamine bond with copper ions. Single-crystal X-ray diffraction and solid-state nuclear magnetic resonance results show that the oxidation state of copper in Cu3Cl(SR)2 is +1 rather than +2. Further, Cu3Cl(SR)2 has been observed to show intense photoluminescence and X-ray excited luminescence. More interesting is that Cu3Cl(SR)2 particles can produce singlet oxygen under irradiation by light or X-ray. This indicatesmore » that Cu3Cl(SR)2 is a new photosensitizer that can be used for deep cancer treatment as X-ray can penetrate soft tissues. All these findings mean that Cu3Cl(SR)2 is a new material with potential applications for lighting, radiation detection and cancer treatment.« less

Optical coherence tomography for nondestructive evaluation of fuel rod degradation

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

Renshaw, Jeremy B., E-mail: jrenshaw@epri.com; Jenkins, Thomas P., E-mail: tjenkins@metrolaserinc.com; Buckner, Benjamin D., E-mail: tjenkins@metrolaserinc.com

Nuclear power plants regularly inspect fuel rods to ensure safe and reliable operation. Excessive corrosion can cause fuel failures which can have significant repercussions for the plant, including impacts on plant operation, worker exposure to radiation, and the plant's INPO rating. While plants typically inspect for fuel rod corrosion using eddy current techniques, these techniques have known issues with reliability in the presence of tenacious, ferromagnetic crud layers that can deposit during operation, and the nondestructive evaluation (NDE) inspection results can often be in error by a factor of 2 or 3. For this reason, alternative measurement techniques, such asmore » Optical Coherence Tomography (OCT), have been evaluated that are not sensitive to the ferromagnetic nature of the crud. This paper demonstrates that OCT has significant potential to characterize the thickness of crud layers that can deposit on the surfaces of fuel rods during operation. Physical trials have been performed on simulated crud samples, and the resulting data show an apparent correlation between the crud layer thickness and the OCT signal.« less

Retention of retinal axon collateral is responsible for induced ipsilateral retinotectal projections in adult goldfish.

PubMed

Sharma, S C; Tsai, C

1991-01-01

In normal goldfish, optic axons innervate only the contralateral optic tectum. When one eye was enucleated and the optic nerve of the other eye crushed, the regenerating optic axons innervated both optic tecta. We studied the presence of bilaterally projecting retinal ganglion cells by double retrograde cell labeling methods using Nuclear Yellow and True Blue dyes. About 10% of the retinal ganglion cells were double labeled and these cells were found throughout the retina. In addition, HRP application to the ipsilateral tectum revealed retrogradely-labeled retinal ganglion cells of all morphological types. These results suggest that induced ipsilateral projections are formed by regenerating axon collaterals and that all cell types are involved in the generation of normal mirror image typography.

Neutron scattering cross section measurements for Fe 56

DOE PAGES

Ramirez, A. P. D.; Vanhoy, J. R.; Hicks, S. F.; ...

2017-06-09

Elastic and inelastic differential cross sections for neutron scattering from 56Fe have been measured for several incident energies from 1.30 to 7.96 MeV at the University of Kentucky Accelerator Laboratory. Scattered neutrons were detected using a C 6D 6 liquid scintillation detector using pulse-shape discrimination and time-of-flight techniques. The deduced cross sections have been compared with previously reported data, predictions from evaluation databases ENDF, JENDL, and JEFF, and theoretical calculations performed using different optical model potentials using the TALYS and EMPIRE nuclear reaction codes. The coupled-channel calculations based on the vibrational and soft-rotor models are found to describe the experimentalmore » (n,n 0) and (n,n 1) cross sections well.« less

Synthesis of Naphthyl-, Quinolin- and Anthracenyl Analogues of Clofibric Acid as PPARα Agonists.

PubMed

Giampietro, Letizia; Ammazzalorso, Alessandra; Bruno, Isabella; Carradori, Simone; De Filippis, Barbara; Fantacuzzi, Marialuigia; Giancristofaro, Antonella; Maccallini, Cristina; Amoroso, Rosa

2016-03-01

PPARα is a ligand activated transcription factor belonging to the nuclear receptor subfamily, involved in fatty acid metabolism in tissues with high oxidative rates such as muscle, heart and liver. PPARα activation is important in steatosis, inflammation and fibrosis in preclinical models of non-alcoholic fatty liver disease identifying a new potential therapeutic area. In this work, three series of clofibric acid analogues conjugated with naphthyl, quinolin, chloroquinolin and anthracenyl scaffolds were synthesized. In an effort to obtain new compounds active as PPARα agonists, these molecules were evaluated for PPARα transactivation activity. Naphthyl and quinolin derivatives showed a good activation of PPARα; noteworthy, optically active naphthyl derivatives activated PPARα better than corresponding parent compound. © 2015 John Wiley & Sons A/S.

Neutron scattering cross section measurements for 56Fe

NASA Astrophysics Data System (ADS)

Ramirez, A. P. D.; Vanhoy, J. R.; Hicks, S. F.; McEllistrem, M. T.; Peters, E. E.; Mukhopadhyay, S.; Harrison, T. D.; Howard, T. J.; Jackson, D. T.; Lenzen, P. D.; Nguyen, T. D.; Pecha, R. L.; Rice, B. G.; Thompson, B. K.; Yates, S. W.

2017-06-01

Elastic and inelastic differential cross sections for neutron scattering from 56Fe have been measured for several incident energies from 1.30 to 7.96 MeV at the University of Kentucky Accelerator Laboratory. Scattered neutrons were detected using a C6D6 liquid scintillation detector using pulse-shape discrimination and time-of-flight techniques. The deduced cross sections have been compared with previously reported data, predictions from evaluation databases ENDF, JENDL, and JEFF, and theoretical calculations performed using different optical model potentials using the talys and empire nuclear reaction codes. The coupled-channel calculations based on the vibrational and soft-rotor models are found to describe the experimental (n ,n0 ) and (n ,n1 ) cross sections well.

A New Compton-thick AGN in our Cosmic Backyard: Unveiling the Buried Nucleus in NGC 1448 with NuSTAR

NASA Astrophysics Data System (ADS)

Annuar, A.; Alexander, D. M.; Gandhi, P.; Lansbury, G. B.; Asmus, D.; Ballantyne, D. R.; Bauer, F. E.; Boggs, S. E.; Boorman, P. G.; Brandt, W. N.; Brightman, M.; Christensen, F. E.; Craig, W. W.; Farrah, D.; Goulding, A. D.; Hailey, C. J.; Harrison, F. A.; Koss, M. J.; LaMassa, S. M.; Murray, S. S.; Ricci, C.; Rosario, D. J.; Stanley, F.; Stern, D.; Zhang, W.

2017-02-01

NGC 1448 is one of the nearest luminous galaxies (L 8-1000μm > 109 L ⊙) to ours (z = 0.00390), and yet the active galactic nucleus (AGN) it hosts was only recently discovered, in 2009. In this paper, we present an analysis of the nuclear source across three wavebands: mid-infrared (MIR) continuum, optical, and X-rays. We observed the source with the Nuclear Spectroscopic Telescope Array (NuSTAR), and combined these data with archival Chandra data to perform broadband X-ray spectral fitting (≈0.5-40 keV) of the AGN for the first time. Our X-ray spectral analysis reveals that the AGN is buried under a Compton-thick (CT) column of obscuring gas along our line of sight, with a column density of N H(los) ≳ 2.5 × 1024 cm-2. The best-fitting torus models measured an intrinsic 2-10 keV luminosity of L {}2-10,{int} = (3.5-7.6) × 1040 erg s-1, making NGC 1448 one of the lowest luminosity CTAGNs known. In addition to the NuSTAR observation, we also performed optical spectroscopy for the nucleus in this edge-on galaxy using the European Southern Observatory New Technology Telescope. We re-classify the optical nuclear spectrum as a Seyfert on the basis of the Baldwin-Philips-Terlevich diagnostic diagrams, thus identifying the AGN at optical wavelengths for the first time. We also present high spatial resolution MIR observations of NGC 1448 with Gemini/T-ReCS, in which a compact nucleus is clearly detected. The absorption-corrected 2-10 keV luminosity measured from our X-ray spectral analysis agrees with that predicted from the optical [O III]λ5007 Å emission line and the MIR 12 μm continuum, further supporting the CT nature of the AGN.

A New Compton-Thick AGN in Our Cosmic Backyard: Unveiling the Buried Nucleus in NGC 1448 with NuSTAR

NASA Technical Reports Server (NTRS)

Annuar, A.; Alexander, D. M.; Ghandi, P.; Lansbury, G. B.; Asmus, D.; Ballantyne, D. R.; Bauer, F. E.; Boggs, S. E.; Boorman, P. G.; Brandt, W. N.;

Inductive Measurement of Optically Hyperpolarized Phosphorous Donor Nuclei in an Isotopically Enriched Silicon-28 Crystal

NASA Astrophysics Data System (ADS)

Gumann, P.; Patange, O.; Ramanathan, C.; Haas, H.; Moussa, O.; Thewalt, M. L. W.; Riemann, H.; Abrosimov, N. V.; Becker, P.; Pohl, H.-J.; Itoh, K. M.; Cory, D. G.

2014-12-01

We experimentally demonstrate the first inductive readout of optically hyperpolarized phosphorus-31 donor nuclear spins in an isotopically enriched silicon-28 crystal. The concentration of phosphorus donors in the crystal was 1.5 ×1 015 cm-3 , 3 orders of magnitude lower than has previously been detected via direct inductive detection. The signal-to-noise ratio measured in a single free induction decay from a 1 cm3 sample (≈1015 spins) was 113. By transferring the sample to an X -band ESR spectrometer, we were able to obtain a lower bound for the nuclear spin polarization at 1.7 K of ˜64 % . The 31P -T2 measured with a Hahn echo sequence was 420 ms at 1.7 K, which was extended to 1.2 s with a Carr Purcell cycle. The T1 of the 31P nuclear spins at 1.7 K is extremely long and could not be determined, as no decay was observed even on a time scale of 4.5 h. Optical excitation was performed with a 1047 nm laser, which provided above-band-gap excitation of the silicon. The buildup of the hyperpolarization at 4.2 K followed a single exponential with a characteristic time of 577 s, while the buildup at 1.7 K showed biexponential behavior with characteristic time constants of 578 and 5670 s.

Continental-scale enrichment of atmospheric 14CO2 from the nuclear power industry: potential impact on the estimation of fossil fuel-derived CO2

NASA Astrophysics Data System (ADS)

Graven, H. D.; Gruber, N.

2011-12-01

The 14C-free fossil carbon added to atmospheric CO2 by combustion dilutes the atmospheric 14C/C ratio (Δ14C), potentially providing a means to verify fossil CO2 emissions calculated using economic inventories. However, sources of 14C from nuclear power generation and spent fuel reprocessing can counteract this dilution and may bias 14C/C-based estimates of fossil fuel-derived CO2 if these nuclear influences are not correctly accounted for. Previous studies have examined nuclear influences on local scales, but the potential for continental-scale influences on Δ14C has not yet been explored. We estimate annual 14C emissions from each nuclear site in the world and conduct an Eulerian transport modeling study to investigate the continental-scale, steady-state gradients of Δ14C caused by nuclear activities and fossil fuel combustion. Over large regions of Europe, North America and East Asia, nuclear enrichment may offset at least 20% of the fossil fuel dilution in Δ14C, corresponding to potential biases of more than -0.25 ppm in the CO2 attributed to fossil fuel emissions, larger than the bias from plant and soil respiration in some areas. Model grid cells including high 14C-release reactors or fuel reprocessing sites showed much larger nuclear enrichment, despite the coarse model resolution of 1.8°×1.8°. The recent growth of nuclear 14C emissions increased the potential nuclear bias over 1985-2005, suggesting that changing nuclear activities may complicate the use of Δ14C observations to identify trends in fossil fuel emissions. The magnitude of the potential nuclear bias is largely independent of the choice of reference station in the context of continental-scale Eulerian transport and inversion studies, but could potentially be reduced by an appropriate choice of reference station in the context of local-scale assessments.

Experimental investigations of a uranium plasma pertinent to a self-sustaining plasma source

NASA Technical Reports Server (NTRS)

Schneider, R. T.

1971-01-01

The research is pertinent to the realization of a self-sustained fissioning plasma for applications such as nuclear propulsion, closed cycle MHD power generation using a plasma core reactor, and heat engines such as the nuclear piston engine, as well as the direct conversion of fission energy into optical radiation (nuclear pumped lasers). Diagnostic measurement methods and experimental devices simulating plasma core reactor conditions are discussed. Studies on the following topics are considered: (1) ballistic piston compressor (U-235); (2) high pressure uranium plasma (natural uranium); (3) sliding spark discharge (natural uranium); (4) fission fragment interaction (He-3 and U-235); and (5) nuclear pumped lasers (He-3 and U-235).

Nuclear Science Symposium, 25th, and Symposium on Nuclear Power Systems, 10th, Washington, D.C., October 18-20, 1978, Proceedings

NASA Technical Reports Server (NTRS)

1979-01-01

Detectors of various types are discussed, taking into account drift chambers, calorimetry, multiwire proportional chambers, signal processing, the use of semiconductors, and photo/optical applications. Circuits are considered along with instrumentation for space, nuclear medicine instrumentation, data acquisition and systems, environmental instrumentation, reactor instrumentation, and nuclear power systems. Attention is given to a new approach to high accuracy gaseous detectors, the current status of electron mobility and free-ion yield in high mobility liquids, a digital drift chamber digitizer system, the stability of oxides in high purity germanium, the quadrant photomultiplier, and the theory of imaging with a very limited number of projections.

Investigation of Retinal Morphology Alterations Using Spectral Domain Optical Coherence Tomography in a Mouse Model of Retinal Branch and Central Retinal Vein Occlusion

PubMed Central

Ebneter, Andreas; Agca, Cavit; Dysli, Chantal; Zinkernagel, Martin S.

2015-01-01

Retinal vein occlusion is a leading cause of visual impairment. Experimental models of this condition based on laser photocoagulation of retinal veins have been described and extensively exploited in mammals and larger rodents such as the rat. However, few reports exist on the use of this paradigm in the mouse. The objective of this study was to investigate a model of branch and central retinal vein occlusion in the mouse and characterize in vivo longitudinal retinal morphology alterations using spectral domain optical coherence tomography. Retinal veins were experimentally occluded using laser photocoagulation after intravenous application of Rose Bengal, a photo-activator dye enhancing thrombus formation. Depending on the number of veins occluded, variable amounts of capillary dropout were seen on fluorescein angiography. Vascular endothelial growth factor levels were markedly elevated early and peaked at day one. Retinal thickness measurements with spectral domain optical coherence tomography showed significant swelling (p<0.001) compared to baseline, followed by gradual thinning plateauing two weeks after the experimental intervention (p<0.001). Histological findings at day seven correlated with spectral domain optical coherence tomography imaging. The inner layers were predominantly affected by degeneration with the outer nuclear layer and the photoreceptor outer segments largely preserved. The application of this retinal vein occlusion model in the mouse carries several advantages over its use in other larger species, such as access to a vast range of genetically modified animals. Retinal changes after experimental retinal vein occlusion in this mouse model can be non-invasively quantified by spectral domain optical coherence tomography, and may be used to monitor effects of potential therapeutic interventions. PMID:25775456

Survey of advanced nuclear technologies for potential applications of sonoprocessing.

PubMed

Rubio, Floren; Blandford, Edward D; Bond, Leonard J

2016-09-01

Ultrasonics has been used in many industrial applications for both sensing at low power and processing at higher power. Generally, the high power applications fall within the categories of liquid stream degassing, impurity separation, and sonochemical enhancement of chemical processes. Examples of such industrial applications include metal production, food processing, chemical production, and pharmaceutical production. There are many nuclear process streams that have similar physical and chemical processes to those applications listed above. These nuclear processes could potentially benefit from the use of high-power ultrasonics. There are also potential benefits to applying these techniques in advanced nuclear fuel cycle processes, and these benefits have not been fully investigated. Currently the dominant use of ultrasonic technology in the nuclear industry has been using low power ultrasonics for non-destructive testing/evaluation (NDT/NDE), where it is primarily used for inspections and for characterizing material degradation. Because there has been very little consideration given to how sonoprocessing can potentially improve efficiency and add value to important process streams throughout the nuclear fuel cycle, there are numerous opportunities for improvement in current and future nuclear technologies. In this paper, the relevant fundamental theory underlying sonoprocessing is highlighted, and some potential applications to advanced nuclear technologies throughout the nuclear fuel cycle are discussed. Copyright © 2016 Elsevier B.V. All rights reserved.

The Sagnac-configured fiber optic calorimeter: An investigation of an improved non-destructive methodology for determining the thermal power output of heat-producing nuclear materials

NASA Astrophysics Data System (ADS)

Bayliss, Stephen Carlton

An essential component in an ever-expanding global nuclear economy is the nondestructive assay (NDA) of nuclear materials. Accurate accounting of these materials helps to insure the safe handling and disposal of them and the accurate monitoring of these materials can help prevent their diversion. A particularly useful and important NDA technique has proven to be isothermal calorimetry. With state-of-the-art calorimeters, heat rates as low as a few milliwatts can be measured, which correspond to approximately one gram of plutonium or one milligram of tritium; two materials of particular interest. In addition, calorimetry is relatively insensitive to the matrix of the sample. This work reports on the development of a calorimeter technique based on fiber optics, which can greatly increase the sensitivity of the calorimeter compared with present day devices. Specifically, this device uses an optical fiber configuration based on the Sagnac interferometer. Fundamentally, the optical fiber is replacing the resistive wire used in conventional calorimeters. The optical fiber is wrapped around two "thermels;" a reference and a sample thermel; the thermal sample to be measured is placed in the sample thermel. The light within the optical fiber of the sample arm experiences a change in phase due to the change in the index of refraction caused by the thermal load. When this light mixes with the light from the reference arm, a change in the light intensity results. An electro-optic receiver converts the time-varying light intensity to a time-varying voltage output. It is this voltage output that is stored and analyzed. A prototype fiber calorimeter has been built and proved capable of measuring heat loads in the microwatt regime. This sensitivity represents a factor of a one thousand-fold improvement over conventional calorimeters. This would allow plutonium samples as small as one milligram to be measured and microgram quantities of tritium. In addition, gram quantities of 93% enriched uranium could be measured for the first time using calorimetry. This device has not been optimized with respect to background interferences (room thermal loads and acoustics), but indications are that the sensitivity could be improved further with more development.

Preliminary Neutronics Analysis of the ITER Toroidal Interferometer and Polarimeter Diagnostic Corner Cube Retroreflectors

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

Tresemer, K. R.

2015-07-01

ITER is an international project under construction in France that will demonstrate nuclear fusion at a power plant-relevant scale. The Toroidal Interferometer and Polarimeter (TIP) Diagnostic will be used to measure the plasma electron line density along 5 laser-beam chords. This line-averaged density measurement will be input to the ITER feedback-control system. The TIP is considered the primary diagnostic for these measurements, which are needed for basic ITER machine control. Therefore, system reliability & accuracy is a critical element in TIP’s design. There are two major challenges to the reliability of the TIP system. First is the survivability and performancemore » of in-vessel optics and second is maintaining optical alignment over long optical paths and large vessel movements. Both of these issues greatly depend on minimizing the overall distortion due to neutron & gamma heating of the Corner Cube Retroreflectors (CCRs). These are small optical mirrors embedded in five first wall locations around the vacuum vessel, corresponding to certain plasma tangency radii. During the development of the design and location of these CCRs, several iterations of neutronics analyses were performed to determine and minimize the total distortion due to nuclear heating of the CCRs. The CCR corresponding to TIP Channel 2 was chosen for analysis as a good middle-road case, being an average distance from the plasma (of the five channels) and having moderate neutron shielding from its blanket shield housing. Results show that Channel 2 meets the requirements of the TIP Diagnostic, but barely. These results suggest other CCRs might be at risk of exceeding thermal deformation due to nuclear heating.« less

Application of nuclear pumped laser to an optical self-powered neutron detector

NASA Astrophysics Data System (ADS)

Yamanaka, N.; Takahashi, H.; Iguchi, T.; Nakazawa, M.; Kakuta, T.; Yamagishi, H.; Katagiri, M.

1996-05-01

A Nuclear Pumped Laser (NPL) using 3He/Ne/Ar gas mixture is investigated for a purpose of applying to an optical self-powered neutron detector. Reactor experiments and simulations on lasing mechanism have been made to estimate the best gas pressure and mixture ratios on the threshold input power density (or thermal neutron flux) in 3He/Ne/Ar mixture. Calculational results show that the best mixture pressure is 3He/Ne/Ar=2280/60/100 Torr and thermal neutron flux threshold 5×1012 n/cm2 sec, while the reactor experiments made in the research reactor ``YAYOI'' of the University of Tokyo and ``JRR-4'' of JAERI also demonstrate that excitational efficiency is maximized in a similar gas mixture predicted by the calculation.

An experimental platform for real-time measurement of the deformation of nuclear fuel rod claddings submitted to thermal transients

NASA Astrophysics Data System (ADS)

Gallais, L.; Burla, R.; Martin, F.; Richaud, J. C.; Volle, G.; Pontillon, M.; Capdevila, H.; Pontillon, Y.

2018-01-01

We report on experimental development and qualification of a system developed to detect and quantify the deformations of the cladding surface of nuclear fuel pellet assemblies submitted to heat transient conditions. The system consists of an optical instrument, based on 2 wavelengths speckle interferometry, associated with an induction furnace and a model pellet assembly used to simulate the radial thermal gradient experienced by fuel pellets in pressurized water reactors. We describe the concept, implementation, and first results obtained with this system. We particularly demonstrate that the optical system is able to provide real time measurements of the cladding surface shape during the heat transients from ambient to high temperatures (up to a cladding surface temperature of 600 °C) with micrometric resolution.

An experimental platform for real-time measurement of the deformation of nuclear fuel rod claddings submitted to thermal transients.

PubMed

Gallais, L; Burla, R; Martin, F; Richaud, J C; Volle, G; Pontillon, M; Capdevila, H; Pontillon, Y

2018-01-01

We report on experimental development and qualification of a system developed to detect and quantify the deformations of the cladding surface of nuclear fuel pellet assemblies submitted to heat transient conditions. The system consists of an optical instrument, based on 2 wavelengths speckle interferometry, associated with an induction furnace and a model pellet assembly used to simulate the radial thermal gradient experienced by fuel pellets in pressurized water reactors. We describe the concept, implementation, and first results obtained with this system. We particularly demonstrate that the optical system is able to provide real time measurements of the cladding surface shape during the heat transients from ambient to high temperatures (up to a cladding surface temperature of 600 °C) with micrometric resolution.

PREFACE: I International Scientific School Methods of Digital Image Processing in Optics and Photonics

NASA Astrophysics Data System (ADS)

Gurov, I. P.; Kozlov, S. A.

2014-09-01

The first international scientific school "Methods of Digital Image Processing in Optics and Photonics" was held with a view to develop cooperation between world-class experts, young scientists, students and post-graduate students, and to exchange information on the current status and directions of research in the field of digital image processing in optics and photonics. The International Scientific School was managed by: Saint Petersburg National Research University of Information Technologies, Mechanics and Optics (ITMO University) - Saint Petersburg (Russia) Chernyshevsky Saratov State University - Saratov (Russia) National research nuclear University "MEPHI" (NRNU MEPhI) - Moscow (Russia) The school was held with the participation of the local chapters of Optical Society of America (OSA), the Society of Photo-Optical Instrumentation Engineers (SPIE) and IEEE Photonics Society. Further details, including topics, committees and conference photos are available in the PDF

Reflectance confocal microscope for imaging oral tissues in vivo, potentially with line scanning as a low-cost approach for clinical use

NASA Astrophysics Data System (ADS)

Peterson, Gary; Abeytunge, Sanjeewa; Eastman, Zachary; Rajadhyaksha, Milind

2012-02-01

Reflectance confocal microscopy with a line scanning approach potentially offers a smaller, simpler and less expensive approach than traditional methods of point scanning for imaging in living tissues. With one moving mechanical element (galvanometric scanner), a linear array detector and off-the-shelf optics, we designed a compact (102x102x76mm) line scanning confocal reflectance microscope (LSCRM) for imaging human tissues in vivo in a clinical setting. Custom-designed electronics, based on field programmable gate array (FPGA) logic has been developed. With 405 nm illumination and a custom objective lens of numerical aperture 0.5, lateral resolution was measured to be 0.8 um (calculated 0.64 um). The calculated optical sectioning is 3.2 um. Preliminary imaging shows nuclear and cellular detail in human skin and oral epithelium in vivo. Blood flow is also visualized in the deeper connective tissue (lamina propria) in oral mucosa. Since a line is confocal only in one dimension (parallel) but not in the other, the detection is more sensitive to multiply scattered out of focus background noise than in the traditional point scanning configuration. Based on the results of our translational studies thus far, a simpler, smaller and lower-cost approach based on a LSCRM appears to be promising for clinical imaging.

Whispering gallery states of neutrons and anti-hydrogen atoms and their applications to fundamental and surface physics

NASA Astrophysics Data System (ADS)

Nesvizhevsky, Valery

2013-03-01

The `whispering gallery' effect has been known since ancient times for sound waves in air, later in water and more recently for a broad range of electromagnetic waves: radio, optics, Roentgen and so on. It is intensively used and explored due to its numerous crucial applications. It consists of wave localization near a curved reflecting surface and is expected for waves of various natures, for instance, for neutrons and (anti)atoms. For (anti)matter waves, it includes a new feature: a massive particle is settled in quantum states, with parameters depending on its mass. In this talk, we present the first observation of the quantum whispering-gallery effect for matter particles (cold neutrons) 1-2. This phenomenon provides an example of an exactly solvable problem analogous to the `quantum bouncer'; it is complementary to recently discovered gravitational quantum states of neutrons3. These two phenomena provide a direct demonstration of the weak equivalence principle for a massive particle in a quantum state. Deeply bound long-living states are weakly sensitive to surface potential; highly excited short-living states are very sensitive to the wall nuclear potential shape. Therefore, they are a promising tool for studying fundamental neutron-matter interactions, quantum neutron optics and surface physics effects. Analogous phenomena could be measured with atoms and anti-atoms 4-5.

PROBLEMS OF THE OPTICAL MODEL FOR DEUTERONS. I. PARAMETERS OF THE OPTICAL POTENTIAL (in Polish)

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

Grotowski, K.

1963-01-01

S>Problems concerning the optical model are discussed. Some special properties of deuterons as projectiles influence the optical model describing their interaction with nuclei. Several experiments were performed to obtain parameters of the optical model potential. (auth)

Potential Nuclear Conflict: Attention Adult Educators.

ERIC Educational Resources Information Center

Gleazer, Edmund J.

1983-01-01

Teaching about potential nuclear conflict is increasing in schools, colleges, and universities. A group of faculty from many universities across the United States has formed United Campuses to Prevent Nuclear War (UCAM) to produce teaching materials and publish summaries of courses on nuclear war. One such course at Lafayette College…

THE DYNACELL AND FOCAL PLANE CONCEPTS OF PHOTOTROPIC SYSTEMS APPLICATION TO OPHTHALMIC NUCLEAR FLASH-PROTECTIVE DEVICES

DTIC Science & Technology

Two concepts of phototropic systems application are presented in this report. These concepts, when considered individually or in combination, make...possible the development of improved, directly or indirectly actuated, phototropic , ophthalmic, nuclear flash-protective devices. By the application...of a phototropic filter at the focal plane of an optical system, the attenuation of the phototropic response due to distance is minimized. Using a

Nuclear quantum effects in a HIV/cancer inhibitor: The case of ellipticine

NASA Astrophysics Data System (ADS)

Sappati, Subrahmanyam; Hassanali, Ali; Gebauer, Ralph; Ghosh, Prasenjit

2016-11-01

Ellipticine is a natural product that is currently being actively investigated for its inhibitory cancer and HIV properties. Here we use path-integral molecular dynamics coupled with excited state calculations to characterize the role of nuclear quantum effects on the structural and electronic properties of ellipticine in water, a common biological solvent. Quantum effects collectively enhance the fluctuations of both light and heavy nuclei of the covalent and hydrogen bonds in ellipticine. In particular, for the ellipticine-water system, where the proton donor and acceptor have different proton affinities, we find that nuclear quantum effects (NQEs) strengthen both the strong and the weak H bonds. This is in contrast to what is observed for the cases where the proton affinity of the donors and acceptors is same. These structural fluctuations cause a significant red-shift in the absorption spectra and an increase in the broadening, bringing it into closer agreement with the experiments. Our work shows that nuclear quantum effects alter both qualitatively and quantitatively the optical properties of this biologically relevant system and highlights the importance of the inclusion of these effects in the microscopic understanding of their optical properties. We propose that isotopic substitution will produce a blue shift and a reduction in the broadening of the absorption peak.

Active Temperature Compensation Using a High-Temperature, Fiber Optic, Hybrid Pressure and Temperature Sensor

NASA Astrophysics Data System (ADS)

Fielder, Robert S.; Palmer, Matthew E.; Davis, Matthew A.; Engelbrecht, Gordon P.

2006-01-01

Luna Innovations has developed a novel, fiber optic, hybrid pressure-temperature sensor system for extremely high-temperature environments that is capable of reliable operation up to 1050 °C. This system is based on the extremely high-temperature fiber optic sensors already demonstrated during previous work. The novelty of the sensors presented here lies in the fact that pressure and temperature are measured simultaneously with a single fiber and a single transducer. This hybrid approach will enable highly accurate active temperature compensation and sensor self-diagnostics not possible with other platforms. Hybrid pressure and temperature sensors were calibrated by varying both pressure and temperature. Implementing active temperature compensation resulted in a ten-fold reduction in the temperature-dependence of the pressure measurement. Sensors were tested for operability in a relatively high neutron dose environment up to 6.9×1017 n/cm2. In addition to harsh environment survivability, fiber optic sensors offer a number of intrinsic advantages for space nuclear power applications including extremely low mass, immunity to electromagnetic interference, self diagnostics / prognostics, and smart sensor capability. Deploying fiber optic sensors on future space exploration missions would provide a substantial improvement in spacecraft instrumentation. Additional development is needed, however, before these advantages can be realized. This paper will highlight recent demonstrations of fiber optic sensors in environments relevant to space nuclear applications. Successes and lessons learned will be highlighted. Additionally, development needs will be covered which will suggest a framework for a coherent plan to continue work in this area.

Kinesin-8 Motors Improve Nuclear Centering by Promoting Microtubule Catastrophe

NASA Astrophysics Data System (ADS)

Glunčić, Matko; Maghelli, Nicola; Krull, Alexander; Krstić, Vladimir; Ramunno-Johnson, Damien; Pavin, Nenad; Tolić, Iva M.

2015-02-01

In fission yeast, microtubules push against the cell edge, thereby positioning the nucleus in the cell center. Kinesin-8 motors regulate microtubule catastrophe; however, their role in nuclear positioning is not known. Here we develop a physical model that describes how kinesin-8 motors affect nuclear centering by promoting a microtubule catastrophe. Our model predicts the improved centering of the nucleus in the presence of motors, which we confirmed experimentally in living cells. The model also predicts a characteristic time for the recentering of a displaced nucleus, which is supported by our experiments where we displaced the nucleus using optical tweezers.

Theory and laboratory astrophysics

NASA Technical Reports Server (NTRS)

Schramm, David N.; Mckee, Christopher F.; Alcock, Charles; Allamandola, Lou; Chevalier, Roger A.; Cline, David B.; Dalgarno, Alexander; Elmegreen, Bruce G.; Fall, S. Michael; Ferland, Gary J.

1991-01-01

Science opportunities in the 1990's are discussed. Topics covered include the large scale structure of the universe, galaxies, stars, star formation and the interstellar medium, high energy astrophysics, and the solar system. Laboratory astrophysics in the 1990's is briefly surveyed, covering such topics as molecular, atomic, optical, nuclear and optical physics. Funding recommendations are given for the National Science Foundation, NASA, and the Department of Energy. Recommendations for laboratory astrophysics research are given.

Integral Field Spectroscopy of Markarian 273: Mapping High-Velocity Gas Flows and an Off-Nucleus Seyfert 2 Nebula.

PubMed

Colina; Arribas; Borne

1999-12-10

Integral field optical spectroscopy with the INTEGRAL fiber-based system is used to map the extended ionized regions and gas flows in Mrk 273, one of the closest ultraluminous infrared galaxies. The Hbeta and [O iii] lambda5007 maps show the presence of two distinct regions separated by 4&arcsec; (3.1 kpc) along position angle (P.A.) 240 degrees. The northeastern region coincides with the optical nucleus of the galaxy and shows the spectral characteristics of LINERs. The southwestern region is dominated by [O iii] emission and is classified as a Seyfert 2. Therefore, in the optical, Mrk 273 is an ultraluminous infrared galaxy with a LINER nucleus and an extended off-nucleus Seyfert 2 nebula. The kinematics of the [O iii] ionized gas shows (1) the presence of highly disturbed gas in the regions around the LINER nucleus, (2) a high-velocity gas flow with a peak-to-peak amplitude of 2.4x103 km s-1, and (3) quiescent gas in the outer regions (at 3 kpc). We hypothesize that the high-velocity flow is the starburst-driven superwind generated in an optically obscured nuclear starburst and that the quiescent gas is directly ionized by a nuclear source, similar to the ionization cones typically seen in Seyfert galaxies.

Monitoring of Concrete Structures Using Ofdr Technique

NASA Astrophysics Data System (ADS)

Henault, J. M.; Salin, J.; Moreau, G.; Delepine-Lesoille, S.; Bertand, J.; Taillade, F.; Quiertant, M.; Benzarti, K.

2011-06-01

Structural health monitoring is a key factor in life cycle management of infrastructures. Truly distributed fiber optic sensors are able to provide relevant information on large structures, such as bridges, dikes, nuclear power plants or nuclear waste disposal facilities. The sensing chain includes an optoelectronic unit and a sensing cable made of one or more optical fibers. A new instrument based on Optical Frequency Domain Reflectometry (OFDR), enables to perform temperature and strain measurements with a centimeter scale spatial resolution over hundred of meters and with a level of precision equal to 1 μstrain and 0.1 °C. Several sensing cables are designed with different materials targeting to last for decades in a concrete aggressive environment and to ensure an optimal transfer of temperature and strain from the concrete matrix to the optical fiber. Tests were carried out by embedding various sensing cables into plain concrete specimens and representative-scale reinforced concrete structural elements. Measurements were performed with an OFDR instrument; meanwhile, mechanical solicitations were imposed to the concrete element. Preliminary experiments are very promising since measurements performed with distributed sensing system are comparable to values obtained with conventional sensors used in civil engineering and with the Strength of Materials Modelling. Moreover, the distributed sensing system makes it possible to detect and localize cracks appearing in concrete during the mechanical loading.

Evaluation of Aerogel Clad Optical Fibers Final Report CRADA No. TSB-1448-97

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

Maitland, Duncan; Droege, M. W.

Fiber-optic based sensors will be needed for in situ monitoring of degradation products in various components of nuclear weapons. These sensors typically consist of a transducer located at the measurement site whose optical properties are modulated by interaction with the targeted degradation product. The interrogating light source and the detector for determining sensor response are located remotely. These two subsystems are connected by fiber optic cables. LLNL has developed a new technology, aerogel clad optical fibers, that have the advantage of accepting incident rays over a much wider angular range than normal glass clad fibers. These fibers are also capablemore » of transmitting light more efficiently. These advantages can lead to a factor of 2-4 improvement in sensitivity and detection limit.« less

Role of optical computers in aeronautical control applications

NASA Technical Reports Server (NTRS)

Baumbick, R. J.

1981-01-01

The role that optical computers play in aircraft control is determined. The optical computer has the potential high speed capability required, especially for matrix/matrix operations. The optical computer also has the potential for handling nonlinear simulations in real time. They are also more compatible with fiber optic signal transmission. Optics also permit the use of passive sensors to measure process variables. No electrical energy need be supplied to the sensor. Complex interfacing between optical sensors and the optical computer is avoided if the optical sensor outputs can be directly processed by the optical computer.

Optimization of a Widefield Structured Illumination Microscope for Non-Destructive Assessment and Quantification of Nuclear Features in Tumor Margins of a Primary Mouse Model of Sarcoma

PubMed Central

Fu, Henry L.; Mueller, Jenna L.; Javid, Melodi P.; Mito, Jeffrey K.; Kirsch, David G.; Ramanujam, Nimmi; Brown, J. Quincy

2013-01-01

Cancer is associated with specific cellular morphological changes, such as increased nuclear size and crowding from rapidly proliferating cells. In situ tissue imaging using fluorescent stains may be useful for intraoperative detection of residual cancer in surgical tumor margins. We developed a widefield fluorescence structured illumination microscope (SIM) system with a single-shot FOV of 2.1×1.6 mm (3.4 mm2) and sub-cellular resolution (4.4 µm). The objectives of this work were to measure the relationship between illumination pattern frequency and optical sectioning strength and signal-to-noise ratio in turbid (i.e. thick) samples for selection of the optimum frequency, and to determine feasibility for detecting residual cancer on tumor resection margins, using a genetically engineered primary mouse model of sarcoma. The SIM system was tested in tissue mimicking solid phantoms with various scattering levels to determine impact of both turbidity and illumination frequency on two SIM metrics, optical section thickness and modulation depth. To demonstrate preclinical feasibility, ex vivo 50 µm frozen sections and fresh intact thick tissue samples excised from a primary mouse model of sarcoma were stained with acridine orange, which stains cell nuclei, skeletal muscle, and collagenous stroma. The cell nuclei were segmented using a high-pass filter algorithm, which allowed quantification of nuclear density. The results showed that the optimal illumination frequency was 31.7 µm−1 used in conjunction with a 4×0.1 NA objective ( = 0.165). This yielded an optical section thickness of 128 µm and an 8.9×contrast enhancement over uniform illumination. We successfully demonstrated the ability to resolve cell nuclei in situ achieved via SIM, which allowed segmentation of nuclei from heterogeneous tissues in the presence of considerable background fluorescence. Specifically, we demonstrate that optical sectioning of fresh intact thick tissues performed equivalently in regards to nuclear density quantification, to physical frozen sectioning and standard microscopy. PMID:23894357

Automatic neutron dosimetry system based on fluorescent nuclear track detector technology.

PubMed

Akselrod, M S; Fomenko, V V; Bartz, J A; Haslett, T L

2014-10-01

For the first time, the authors are describing an automatic fluorescent nuclear track detector (FNTD) reader for neutron dosimetry. FNTD is a luminescent integrating type of detector made of aluminium oxide crystals that does not require electronics or batteries during irradiation. Non-destructive optical readout of the detector is performed using a confocal laser scanning fluorescence imaging with near-diffraction limited resolution. The fully automatic table-top reader allows one to load up to 216 detectors on a tray, read their engraved IDs using a CCD camera and optical character recognition, scan and process simultaneously two types of images in fluorescent and reflected laser light contrast to eliminate false-positive tracks related to surface and volume crystal imperfections. The FNTD dosimetry system allows one to measure neutron doses from 0.1 mSv to 20 Sv and covers neutron energies from thermal to 20 MeV. The reader is characterised by a robust, compact optical design, fast data processing electronics and user-friendly software. © The Author 2013. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Ultrafast time scale X-rotation of cold atom storage qubit using Rubidium clock states

NASA Astrophysics Data System (ADS)

Song, Yunheung; Lee, Han-Gyeol; Kim, Hyosub; Jo, Hanlae; Ahn, Jaewook

2017-04-01

Ultrafast-time-scale optical interaction is a local operation on the electronic subspace of an atom, thus leaving its nuclear state intact. However, because atomic clock states are maximally entangled states of the electronic and nuclear degrees of freedom, their entire Hilbert space should be accessible only with local operations and classical communications (LOCC). Therefore, it may be possible to achieve hyperfine qubit gates only with electronic transitions. Here we show an experimental implementation of ultrafast X-rotation of atomic hyperfine qubits, in which an optical Rabi oscillation induces a geometric phase between the constituent fine-structure states, thus bringing about the X-rotation between the two ground hyperfine levels. In experiments, cold atoms in a magneto-optical trap were controlled with a femtosecond laser pulse from a Ti:sapphire laser amplifier. Absorption imaging of the as-controlled atoms initially in the ground hyperfine state manifested polarization dependence, strongly agreeing with the theory. The result indicates that single laser pulse implementations of THz clock speed qubit controls are feasible for atomic storage qubits. Samsung Science and Technology Foundation [SSTF-BA1301-12].

Radiolabeled mannosylated dextran derivatives bearing an NIR-fluorophore for sentinel lymph node imaging.

PubMed

Morais, Maurício; Campello, Maria P C; Xavier, Catarina; Heemskerk, Johannes; Correia, João D G; Lahoutte, Tony; Caveliers, Vicky; Hernot, Sophie; Santos, Isabel

2014-11-19

Current methods for sentinel lymph node (SLN) mapping involve the use of radioactivity detection with technetium-99m sulfur colloid and/or visually guided identification using a blue dye. To overcome the kinetic variations of two individual imaging agents through the lymphatic system, we report herein on two multifunctional macromolecules, 5a and 6a, that contain a radionuclide ((99m)Tc or (68)Ga) and a near-infrared (NIR) reporter for pre- and/or intraoperative SLN mapping by nuclear and NIR optical imaging techniques. Both bimodal probes are dextran-based polymers (10 kDa) functionalized with pyrazole-diamine (Pz) or 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) chelating units for labeling with fac-[(99m)Tc(CO)3](+) or (68)Ga(III), respectively, mannose units for receptor targeting, and NIR fluorophore units for optical imaging. The probes allowed a clear visualization of the popliteal node by single-photon emission computed tomography (SPECT/CT) or positron emission tomography (PET/CT), as well as real-time optically guided excision. Biodistribution studies confirmed that both macromolecules present a significant accumulation in the popliteal node (5a: 3.87 ± 0.63% IA/organ; 6a: 1.04 ± 0.26% IA/organ), with minimal spread to other organs. The multifunctional nanoplatforms display a popliteal extraction efficiency >90%, highlighting their potential to be further explored as dual imaging agents.

Development of Metal Oxide Nanostructure-based Optical Sensors for Fossil Fuel Derived Gases Measurement at High Temperature

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

Chen, Kevin P.

2015-02-13

This final technical report details research works performed supported by a Department of Energy grant (DE-FE0003859), which was awarded under the University Coal Research Program administrated by National Energy Technology Laboratory. This research program studied high temperature fiber sensor for harsh environment applications. It developed two fiber optical sensor platform technology including regenerative fiber Bragg grating sensors and distributed fiber optical sensing based on Rayleigh backscattering optical frequency domain reflectometry. Through the studies of chemical and thermal regenerative techniques for fiber Bragg grating (FBG) fabrication, high-temperature stable FBG sensors were successfully developed and fabricated in air-hole microstructured fibers, high-attenuation fibers,more » rare-earth doped fibers, and standard telecommunication fibers. By optimizing the laser processing and thermal annealing procedures, fiber grating sensors with stable performance up to 1100°C have been developed. Using these temperature-stable FBG gratings as sensor platform, fiber optical flow, temperature, pressure, and chemical sensors have been developed to operate at high temperatures up to 800°C. Through the integration of on-fiber functional coating, the use of application-specific air-hole microstructural fiber, and application of active fiber sensing scheme, distributed fiber sensor for temperature, pressure, flow, liquid level, and chemical sensing have been demonstrated with high spatial resolution (1-cm or better) with wide temperature ranges. These include the demonstration of 1) liquid level sensing from 77K to the room temperature, pressure/temperature sensing from the room temperature to 800C and from the 15psi to 2000 psi, and hydrogen concentration measurement from 0.2% to 10% with temperature ranges from the room temperature to 700°C. Optical sensors developed by this program has broken several technical records including flow sensors with the highest operation temperature up to 750°C, first distributed chemical measurements at the record high temperature up to 700°C, first distributed pressure measurement at the record high temperature up to 800°C, and the fiber laser sensors with the record high operation temperature up to 700°C. The research performed by this program dramatically expand the functionality, adaptability, and applicability of distributed fiber optical sensors with potential applications in a number of high-temperature energy systems such as fossil-fuel power generation, high-temperature fuel cell applications, and potential for nuclear energy systems.« less

Lunar sample contracts

NASA Technical Reports Server (NTRS)

Walker, R. M.

1974-01-01

The major scientific accomplishments through 1971 are reported for the particle track studies of lunar samples. Results are discussed of nuclear track measurements by optical and electron microscopy, thermoluminescence, X-ray diffraction, and differential thermal analysis.

Equation of state of asymmetric nuclear matter using re-projected nucleon–nucleon potentials

NASA Astrophysics Data System (ADS)

Asadi Aghbolaghi, Z.; Bigdeli, M.

2018-06-01

In this paper, we have calculated the equation of state of asymmetric nuclear matter using the lowest order constrained variational approach and Argonne family potentials with and without three-nucleon interaction (TNI) contribution. In particular, we have used the AV18 potential and the re-projected potentials, AV8‧, and AV6‧. We have also calculated the saturation properties of symmetric nuclear matter, and the nuclear symmetry energy using AV18+TNI, AV8‧+TNI and AV6‧+TNI potentials. The inclusion of TNI has modified the agreement with experiment. We have also made a comparison between our results and those of other many-body calculations.

Study of the optical properties and the carbonaceous clusters in DAM-ADC solid state nuclear track detectors

NASA Astrophysics Data System (ADS)

Rammah, Y. S.; Abdalla, A. M.

2017-12-01

The optical properties of DAM-ADC solid state nuclear track detectors (SSNTDs) were investigated. Samples of DAM-ADC detector were irradiated at room temperature with gamma doses in the range of 100-500 kGy using 1.25 MeV 60Co source of dose rate 4 kGy/h. The optical characterization of these detectors have been studied through the measurements of UV-visible absorption spectra of blank and γ- irradiated samples. The optical energy band gaps, Eg for the detectors were obtained from the direct and the indirect allowed transitions in K-space using two methods (Tauc's model and absorption spectrum fitting (ASF) method). The absorbance of DAM-ADC detector was found to increase with increasing of the gamma absorbed dose. The width of the tail of localized states in the band gap, Eu was evaluated with the Urbach's method. The number of carbon atoms per conjugated length (N), the number of carbon atoms per cluster (M), and refractive index (n) for the present samples were determined. Both of the direct and the indirect band gaps of DAM-ADC detector decrease with increasing of the gamma absorbed dose. Urbach's energy decreased significantly for the detector. An increase in N, M, and n with increasing of the gamma absorbed dose was noticed. Results shed light on the effect of gamma irradiations of DAM-ADC SSNTDs to suitable industrial applications and to modify the optical properties through gamma-induced modifications of the polymer structure.

Detecting ionizing radiation with optical fibers down to biomedical doses

NASA Astrophysics Data System (ADS)

Avino, S.; D'Avino, V.; Giorgini, A.; Pacelli, R.; Liuzzi, R.; Cella, L.; De Natale, P.; Gagliardi, G.

2013-10-01

We report on a passive ionizing radiation sensor based on a fiber-optic resonant cavity interrogated by a high resolution interferometric technique. After irradiation in clinical linear accelerators, we observe significant variations of the fiber thermo-optic coefficient. Exploiting this effect, we demonstrate an ultimate detection limit of 160 mGy with an interaction volume of only 6 × 10-4 mm3. Thanks to its reliability, compactness, and sensitivity at biomedical dose levels, our system lends itself to real applications in radiation therapy procedures as well as in radiation monitoring and protection in medicine, aerospace, and nuclear power plants.

Sodium leak detection system for liquid metal cooled nuclear reactors

DOEpatents

Modarres, Dariush

1991-01-01

A light source is projected across the gap between the containment vessel and the reactor vessel. The reflected light is then analyzed with an absorption spectrometer. The presence of any sodium vapor along the optical path results in a change of the optical transmissivity of the media. Since the absorption spectrum of sodium is well known, the light source is chosen such that the sensor is responsive only to the presence of sodium molecules. The optical sensor is designed to be small and require a minimum of amount of change to the reactor containment vessel.

Laser pixelation of thick scintillators for medical imaging applications: x-ray studies

NASA Astrophysics Data System (ADS)

Sabet, Hamid; Kudrolli, Haris; Marton, Zsolt; Singh, Bipin; Nagarkar, Vivek V.

2013-09-01

To achieve high spatial resolution required in nuclear imaging, scintillation light spread has to be controlled. This has been traditionally achieved by introducing structures in the bulk of scintillation materials; typically by mechanical pixelation of scintillators and fill the resultant inter-pixel gaps by reflecting materials. Mechanical pixelation however, is accompanied by various cost and complexity issues especially for hard, brittle and hygroscopic materials. For example LSO and LYSO, hard and brittle scintillators of interest to medical imaging community, are known to crack under thermal and mechanical stress; the material yield drops quickly with large arrays with high aspect ratio pixels and therefore the pixelation process cost increases. We are utilizing a novel technique named Laser Induced Optical Barriers (LIOB) for pixelation of scintillators that overcomes the issues associated with mechanical pixelation. In this technique, we can introduce optical barriers within the bulk of scintillator crystals to form pixelated arrays with small pixel size and large thickness. We applied LIOB to LYSO using a high-frequency solid-state laser. Arrays with different crystal thickness (5 to 20 mm thick), and pixel size (0.8×0.8 to 1.5×1.5 mm2) were fabricated and tested. The width of the optical barriers were controlled by fine-tuning key parameters such as lens focal spot size and laser energy density. Here we report on LIOB process, its optimization, and the optical crosstalk measurements using X-rays. There are many applications that can potentially benefit from LIOB including but not limited to clinical/pre-clinical PET and SPECT systems, and photon counting CT detectors.

Quantum Dots

NASA Astrophysics Data System (ADS)

Tartakovskii, Alexander

2012-07-01

Part I. Nanostructure Design and Structural Properties of Epitaxially Grown Quantum Dots and Nanowires: 1. Growth of III/V semiconductor quantum dots C. Schneider, S. Hofling and A. Forchel; 2. Single semiconductor quantum dots in nanowires: growth, optics, and devices M. E. Reimer, N. Akopian, M. Barkelid, G. Bulgarini, R. Heeres, M. Hocevar, B. J. Witek, E. Bakkers and V. Zwiller; 3. Atomic scale analysis of self-assembled quantum dots by cross-sectional scanning tunneling microscopy and atom probe tomography J. G. Keizer and P. M. Koenraad; Part II. Manipulation of Individual Quantum States in Quantum Dots Using Optical Techniques: 4. Studies of the hole spin in self-assembled quantum dots using optical techniques B. D. Gerardot and R. J. Warburton; 5. Resonance fluorescence from a single quantum dot A. N. Vamivakas, C. Matthiesen, Y. Zhao, C.-Y. Lu and M. Atature; 6. Coherent control of quantum dot excitons using ultra-fast optical techniques A. J. Ramsay and A. M. Fox; 7. Optical probing of holes in quantum dot molecules: structure, symmetry, and spin M. F. Doty and J. I. Climente; Part III. Optical Properties of Quantum Dots in Photonic Cavities and Plasmon-Coupled Dots: 8. Deterministic light-matter coupling using single quantum dots P. Senellart; 9. Quantum dots in photonic crystal cavities A. Faraon, D. Englund, I. Fushman, A. Majumdar and J. Vukovic; 10. Photon statistics in quantum dot micropillar emission M. Asmann and M. Bayer; 11. Nanoplasmonics with colloidal quantum dots V. Temnov and U. Woggon; Part IV. Quantum Dot Nano-Laboratory: Magnetic Ions and Nuclear Spins in a Dot: 12. Dynamics and optical control of an individual Mn spin in a quantum dot L. Besombes, C. Le Gall, H. Boukari and H. Mariette; 13. Optical spectroscopy of InAs/GaAs quantum dots doped with a single Mn atom O. Krebs and A. Lemaitre; 14. Nuclear spin effects in quantum dot optics B. Urbaszek, B. Eble, T. Amand and X. Marie; Part V. Electron Transport in Quantum Dots Fabricated by Lithographic Techniques: III-V Semiconductors and Carbon: 15. Electrically controlling single spin coherence in semiconductor nanostructures Y. Dovzhenko, K. Wang, M. D. Schroer and J. R. Petta; 16. Theory of electron and nuclear spins in III-V semiconductor and carbon-based dots H. Ribeiro and G. Burkard; 17. Graphene quantum dots: transport experiments and local imaging S. Schnez, J. Guettinger, F. Molitor, C. Stampfer, M. Huefner, T. Ihn and K. Ensslin; Part VI. Single Dots for Future Telecommunications Applications: 18. Electrically operated entangled light sources based on quantum dots R. M. Stevenson, A. J. Bennett and A. J. Shields; 19. Deterministic single quantum dot cavities at telecommunication wavelengths D. Dalacu, K. Mnaymneh, J. Lapointe, G. C. Aers, P. J. Poole, R. L. Williams and S. Hughes; Index.

Important role of projectile excitation in 16O+60Ni and 16O+27Al scattering at intermediate energies

NASA Astrophysics Data System (ADS)

Zagatto, V. A. B.; Cappuzzello, F.; Lubian, J.; Cavallaro, M.; Linares, R.; Carbone, D.; Agodi, C.; Foti, A.; Tudisco, S.; Wang, J. S.; Oliveira, J. R. B.; Hussein, M. S.

2018-05-01

The elastic scattering angular distribution of the 16O+60Ni system at 260 MeV was measured in the range of the Rutherford cross section down to seven orders of magnitude. The cross sections of the lowest 2+ and 3- inelastic states of the target were also measured over several orders of magnitude. Coupled-channel (CC) calculations were performed and are shown to be compatible with the whole set of data only when including the excitation of the projectile and when the deformations of the imaginary part of the nuclear optical potential are taken into account. Similar results were obtained when the procedure is applied to the existing data on 16O+27Al elastic and inelastic scattering at 100 and 280 MeV. An analysis in terms of dynamical polarization potentials (DPP) indicates the major role of coupled-channel effects in the overlapping surface region of the colliding nuclei.

Development and characterisation of polymeric microparticle of poly(d,l-lactic acid) loaded with holmium acetylacetonate.

PubMed

de Azevedo, Mariangela de Burgos M; de Melo, Vitor H S; Soares, Carlos Roberto J; Miyamoto, Douglas M; Katayama, Ricardo A; Squair, Peterson L; Barros, Caio H N; Tasic, Ljubica

2018-06-14

Biodegradable polymers containing radioactive isotopes such as Holmium 166 ( 166 Ho) have potential applications as beta particle emitters in tumour tissues. It is also a gamma ray emitter, allowing nuclear imaging of any tissue to be acquired. It is frequently used in the form of complexes such as holmium acetylacetonate (HoAcAc), which may cause damages in tissues next to the targets cancer cells, as it is difficult to control its linkage or healthy tissues radiotherapy effects. Poly(d,l-lactic acid), PDLLA, was used to encapsulate holmium acetylacetonate (HoAcAc) using an emulsion solvent extraction/evaporation technique. Microspheres with sizes between 20-53 µm were extensively characterised. HoAcAc release from the microspheres was assessed through studies using Inductively Coupled Plasma - Optical Emission Spectroscopy, and the microspheres showed no holmium leakage after a period of 10 half-lives and following gamma irradiation. Thus, HoAcAc loaded microspheres are here presented as a potential system for brachytherapy and imaging purposes.

Optical fiber sensors measurement system and special fibers improvement

NASA Astrophysics Data System (ADS)

Jelinek, Michal; Hrabina, Jan; Hola, Miroslava; Hucl, Vaclav; Cizek, Martin; Rerucha, Simon; Lazar, Josef; Mikel, Bretislav

2017-06-01

We present method for the improvement of the measurement accuracy in the optical frequency spectra measurements based on tunable optical filters. The optical filter was used during the design and realization of the measurement system for the inspection of the fiber Bragg gratings. The system incorporates a reference block for the compensation of environmental influences, an interferometric verification subsystem and a PC - based control software implemented in LabView. The preliminary experimental verification of the measurement principle and the measurement system functionality were carried out on a testing rig with a specially prepared concrete console in the UJV Řež. The presented system is the laboratory version of the special nuclear power plant containment shape deformation measurement system which was installed in the power plant Temelin during last year. On the base of this research we started with preparation other optical fiber sensors to nuclear power plants measurement. These sensors will be based on the microstructured and polarization maintaining optical fibers. We started with development of new methods and techniques of the splicing and shaping optical fibers. We are able to made optical tapers from ultra-short called adiabatic with length around 400 um up to long tapers with length up to 6 millimeters. We developed new techniques of splicing standard Single Mode (SM) and Multimode (MM) optical fibers and splicing of optical fibers with different diameters in the wavelength range from 532 to 1550 nm. Together with development these techniques we prepared other techniques to splicing and shaping special optical fibers like as Polarization-Maintaining (PM) or hollow core Photonic Crystal Fiber (PCF) and theirs cross splicing methods with focus to minimalize backreflection and attenuation. The splicing special optical fibers especially PCF fibers with standard telecommunication and other SM fibers can be done by our developed techniques. Adjustment of the splicing process has to be prepared for any new optical fibers and new fibers combinations. The splicing of the same types of fibers from different manufacturers can be adjusted by several tested changes in the splicing process. We are able to splice PCF with standard telecommunication fiber with attenuation up to 2 dB. The method is also presented. Development of these new techniques and methods of the optical fibers splicing are made with respect to using these fibers to another research and development in the field of optical fibers sensors, laser frequency stabilization and laser interferometry based on optical fibers. Especially for the field of laser frequency stabilization we developed and present new techniques to closing microstructured fibers with gases inside.

Nuclear Forensics. Chapter 18

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

Mayer, Klaus; Glaser, Alexander

Whenever nuclear material is found out of regulatory control, questions on the origin of the material, on its intended use, and on hazards associated with the material need to be answered. Here, analytical and interpretational methodologies have been developed in order to exploit measurable material properties for gaining information on the history of the nuclear material. This area of research is referred to as nuclear forensic science or, in short, nuclear forensics.This chapter reviews the origins, types, and state-of-the-art of nuclear forensics; discusses the potential roles of nuclear forensics in supporting nuclear security; and examines what nuclear forensics can realisticallymore » achieve. Lastly, it also charts a path forward, pointing at potential applications of nuclear forensic methodologies in other areas.« less

Nuclear Forensics

DOE PAGES

Glaser, Alexander; Mayer, Klaus

2016-06-01

Whenever nuclear material is found out of regulatory control, questions on the origin of the material, on its intended use, and on hazards associated with the material need to be answered. Analytical and interpretational methodologies have been developed in order to exploit measurable material properties for gaining information on the history of the nuclear material. This area of research is referred to as nuclear forensic science or, in short, nuclear forensics.This chapter reviews the origins, types, and state-of-the-art of nuclear forensics; discusses the potential roles of nuclear forensics in supporting nuclear security; and examines what nuclear forensics can realistically achieve.more » It also charts a path forward, pointing at potential applications of nuclear forensic methodologies in other areas.« less

Optically-based Sensor System for Critical Nuclear Facilities Post-Event Seismic Structural Assessment

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

McCallen, David; Petrone, Floriana; Buckle, Ian

The U.S. Department of Energy (DOE) has ownership and operational responsibility for a large enterprise of nuclear facilities that provide essential functions to DOE missions ranging from national security to discovery science and energy research. These facilities support a number of DOE programs and offices including the National Nuclear Security Administration, Office of Science, and Office of Environmental Management. With many unique and “one of a kind” functions, these facilities represent a tremendous national investment, and assuring their safety and integrity is fundamental to the success of a breadth of DOE programs. Many DOE critical facilities are located in regionsmore » with significant natural phenomenon hazards including major earthquakes and DOE has been a leader in developing standards for the seismic analysis of nuclear facilities. Attaining and sustaining excellence in nuclear facility design and management must be a core competency of the DOE. An important part of nuclear facility management is the ability to monitor facilities and rapidly assess the response and integrity of the facilities after any major upset event. Experience in the western U.S. has shown that understanding facility integrity after a major earthquake is a significant challenge which, lacking key data, can require extensive effort and significant time. In the work described in the attached report, a transformational approach to earthquake monitoring of facilities is described and demonstrated. An entirely new type of optically-based sensor that can directly and accurately measure the earthquake-induced deformations of a critical facility has been developed and tested. This report summarizes large-scale shake table testing of the sensor concept on a representative steel frame building structure, and provides quantitative data on the accuracy of the sensor measurements.« less

Foveomacular schisis in juvenile X-linked retinoschisis: an optical coherence tomography study.

PubMed

Yu, Jia; Ni, Yingqin; Keane, Pearse A; Jiang, Chunhui; Wang, Wenji; Xu, Gezhi

2010-06-01

To explore the structural features of juvenile X-linked retinoschisis using spectral-domain optical coherence tomography (OCT). Retrospective, observational cross-sectional study. Eighteen male patients (34 eyes) who were diagnosed with juvenile X-linked retinoschisis at the Eye & ENT Hospital of Fudan University over an 18-month period were included. Their OCT images, which were obtained using spectral-domain OCT (Cirrus HD-OCT; Carl Zeiss Meditec), were analyzed. The anatomic location of the schisis cavity in juvenile X-linked retinoschisis was characterized by direct inspection of OCT images. On OCT, the schisis cavity was visible at the fovea in all 34 eyes, and it was associated with increased retinal thickness. Schisis was present at the retinal nerve fiber layer in 4 eyes, at the inner nuclear layer in 29 eyes, and at the outer nuclear layer/outer plexiform layer in 22 eyes. In most cases, widespread foveomacular schisis was detected using OCT; however, in 9 eyes (6 patients), the schisis was confined to the fovea. Schisis of the inner nuclear layer and outer nuclear layer/outer plexiform layer almost always involved the foveal center, but retinal nerve fiber layer schisis was seen only in the parafoveal area. Despite conventional wisdom, in patients with X-linked retinoschisis, the schisis cavity can occur in a number of different layers of the neurosensory retina (retinal nerve fiber layer, inner nuclear layer, and outer nuclear layer/outer plexiform layer). In addition, different forms of schisis may affect different locations in the macula (foveal vs parafoveal), and, in most eyes, the schisis involves the entire foveomacular region. Copyright 2010 Elsevier Inc. All rights reserved.

JPRS report: Science and technology. USSR: Engineering and equipment

NASA Astrophysics Data System (ADS)

1991-10-01

A bibliography is given of U.S.S.R. research in engineering and equipment. Topics covered include aviation, space technology, optics, high energy devices, nuclear energy, and industrial technology, planning, and productivity.

Nuclear Spin relaxation mediated by Fermi-edge electrons in n-type GaAs

NASA Astrophysics Data System (ADS)

Kotur, M.; Dzhioev, R. I.; Kavokin, K. V.; Korenev, V. L.; Namozov, B. R.; Pak, P. E.; Kusrayev, Yu. G.

2014-03-01

A method based on the optical orientation technique was developed to measure the nuclear-spin lattice relaxation time T 1 in semiconductors. It was applied to bulk n-type GaAs, where T 1 was measured after switching off the optical excitation in magnetic fields from 400 to 1200 G at low (< 30 K) temperatures. The spin-lattice relaxation of nuclei in the studied sample with n D = 9 × 1016 cm-3 was found to be determined by hyperfine scattering of itinerant electrons (Korringa mechanism) which predicts invariability of T 1 with the change in magnetic field and linear dependence of the relaxation rate on temperature. This result extends the experimentally verified applicability of the Korringa relaxation law in degenerate semiconductors, previously studied in strong magnetic fields (several Tesla), to the moderate field range.

Fiber Optic Tamper Indicating Enclosure (TIE); A Case Study in Authentication

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

Anheier, Norman C.; Benz, Jacob M.; Tanner, Jennifer E.

2015-07-15

A robust fiber optic-based tamper-indicating enclosure (TIE) has been developed by PNNL through funding by the National Nuclear Security Administration Office of Nuclear Verification over the past few years. The objective of this work is to allow monitors to have confidence in both the authenticity and integrity of the TIE and the monitoring equipment inside, throughout the time it may be located at a host facility. Incorporating authentication features into the design were the focus of fiscal year 2014 development efforts. Throughout the development process, modifications have been made to the physical TIE design based on lessons learned via exercisesmore » and expert elicitation. The end result is a robust and passive TIE which can be utilized to protect monitoring party equipment left in a host facility.« less

Spin-injection optical pumping of molten cesium salt and its NMR diagnosis

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

Ishikawa, Kiyoshi

2015-07-15

Nuclear spin polarization of cesium ions in the salt was enhanced during optical pumping of cesium vapor at high magnetic field. Significant motional narrowing and frequency shift of NMR signals were observed by intense laser heating of the salt. When the hyperpolarized salt was cooled by blocking the heating laser, the signal width and frequency changed during cooling and presented the phase transition from liquid to solid. Hence, we find that the signal enhancement is mostly due to the molten salt and nuclear spin polarization is injected into the salt efficiently in the liquid phase. We also show that opticalmore » pumping similarly induces line narrowing in the solid phase. The use of powdered salt provided an increase in effective surface area and signal amplitude without glass wool in the glass cells.« less

The use of stimulated electron emission (SEE) in homeland security applications

NASA Astrophysics Data System (ADS)

Ing, H.; Andrews, H. R.; Facina, M.; Lee, W. T.; Niu, H. W.

2012-06-01

Certain insulating solids can store a fraction of the absorbed energy when irradiated by ionizing radiation. The stored energy can be released subsequently by heating or optical stimulation. As a result, light may be emitted through Thermoluminescence (TL) or Optically-Stimulated Luminescence (OSL) and electrons may be emitted through Thermally-Stimulated Electron Emission (TSEE) or Optically-Stimulated Electron Emission (OSEE). TL and OSL are widely used in current radiation dosimetry systems. However, despite considerable research effort during the early 1970s, SEE was not commonly adopted for dosimetry applications. One of the main reasons is that SEE is a surface phenomenon, while luminescence is a bulk phenomenon, making SEE more susceptible to humidity, absorption of gases, minor physical defects and handling, both before and after irradiation. Nevertheless, it has been recognized that SEE may be useful for homeland security applications in nuclear forensics, where dose accuracy is not the primary performance metric. In this research, we are investigating the use of SEE for nuclear forensic applications. Many common materials, both natural and man-made, exhibit the phenomenon, providing an opportunity to use the environment itself as an in-situ radiation detector. We have designed and constructed a unique prototype reader for conducting SEE measurements. We have demonstrated that the SEE measurements from a variety of materials are quantitatively reproducible and correlated to radiation exposure. Due to the broad applicability of SEE, significant additional studies are warranted to optimize this novel technique for nuclear forensic and other applications.

Spectroscopic Measurement of LEAD-204 Isotope Shift and LEAD-205 Nuclear Spin.

NASA Astrophysics Data System (ADS)

Schonberger, Peter

The isotope shift of ('204)Pb and the nuclear spin of 1.4 x 10('7)-y ('205)Pb was determined from a high -resolution optical measurement of the 6p('2) ('3)P(,o) -6p7s('3)P(,1)('o) 283.3-nm resonance line. The value of the shift, relative to ('208)Pb is -140.2(8) x 10('-3)cm(' -1), the negative sign indicating a shift to lower wave numbers. The precision is 3-4 times greater than that of previous measurements. The spin of ('205)Pb l = 5/2 was obtained from the measurement of the relative intensities of its three hyperfine components. This method of absorption spectroscopy determination of ground state nuclear spin is applicable to any stable or longlived isotope. High resolution optical absorption spectra were obtained with a 25.4cm diffraction grating in a 9.1m focal length Czerny-Turner spectrometer. A signal-averaging scanning technique was used to record the spectra. Increased precision in the isotope shift measurement was attained by using separated isotope samples of ('204)Pb and ('207)Pb. A controlled amount of the later was incorporated in the absorption cell to provide internal calibration by its 6p7s ('3)P(,1)('o) hfs separation. Absorption spectra were recorded for several optical thicknesses of the absorber. A single spin value of increased precision was derived from the entire set of combined data.

JPRS Report, Science & Technology. USSR: Physics & Mathematics

DTIC Science & Technology

1987-10-29

Pulse Holography (S. D. Nikolayev, I. 0. Starobogatov; OPTIKA I SPEKTROSKOPIYA, No 5, Nov 86) 22 NUCLEAR PHYSICS Masses of Vector and Quasi-Scalar...86) 32 Anomalous Evolution of Optical Solitons (S. 0. Yelyutin, A. I. Maymistov; OPTIKA I SPEKTROSKOPIYA, No 5, Nov 86) • ."’. 33 Four-Level...of Polarization Modes in Birefringent Single-Mode Fiber-Optic Waveguide (F. A. Shatalov; OPTIKA I SPEKTROSKOPIYA, No 2, Feb 87)..’.. 3U High

Working Beyond Moore’s Limit - Coherent Nonlinear Optical Control of Individual and Coupled Single Electron Doped Quantum Dots

DTIC Science & Technology

2015-07-06

preparation for deterministic spin-photon entanglement ; (3) Demonstration of initialization of the 2 qubit states; (4) Demonstration of nonlocal nuclear...Demonstration of a flying qubit by entanglement of the quantum dot spin polarization with the polarization of a spontaneously emitted photon. Future...coherent optical control steps in preparation for deterministic spin-photon entanglement ; (3) Demonstration of initialization of the 2 qubit states in

Optical mapping of optogenetically shaped cardiac action potentials.

PubMed

Park, Sarah A; Lee, Shin-Rong; Tung, Leslie; Yue, David T

2014-08-19

Light-mediated silencing and stimulation of cardiac excitability, an important complement to electrical stimulation, promises important discoveries and therapies. To date, cardiac optogenetics has been studied with patch-clamp, multielectrode arrays, video microscopy, and an all-optical system measuring calcium transients. The future lies in achieving simultaneous optical acquisition of excitability signals and optogenetic control, both with high spatio-temporal resolution. Here, we make progress by combining optical mapping of action potentials with concurrent activation of channelrhodopsin-2 (ChR2) or halorhodopsin (eNpHR3.0), via an all-optical system applied to monolayers of neonatal rat ventricular myocytes (NRVM). Additionally, we explore the capability of ChR2 and eNpHR3.0 to shape action-potential waveforms, potentially aiding the study of short/long QT syndromes that result from abnormal changes in action potential duration (APD). These results show the promise of an all-optical system to acquire action potentials with precise temporal optogenetics control, achieving a long-sought flexibility beyond the means of conventional electrical stimulation.

Optical mapping of optogenetically shaped cardiac action potentials

PubMed Central

Park, Sarah A.; Lee, Shin-Rong; Tung, Leslie; Yue, David T.

2014-01-01

Light-mediated silencing and stimulation of cardiac excitability, an important complement to electrical stimulation, promises important discoveries and therapies. To date, cardiac optogenetics has been studied with patch-clamp, multielectrode arrays, video microscopy, and an all-optical system measuring calcium transients. The future lies in achieving simultaneous optical acquisition of excitability signals and optogenetic control, both with high spatio-temporal resolution. Here, we make progress by combining optical mapping of action potentials with concurrent activation of channelrhodopsin-2 (ChR2) or halorhodopsin (eNpHR3.0), via an all-optical system applied to monolayers of neonatal rat ventricular myocytes (NRVM). Additionally, we explore the capability of ChR2 and eNpHR3.0 to shape action-potential waveforms, potentially aiding the study of short/long QT syndromes that result from abnormal changes in action potential duration (APD). These results show the promise of an all-optical system to acquire action potentials with precise temporal optogenetics control, achieving a long-sought flexibility beyond the means of conventional electrical stimulation. PMID:25135113

Effect of the timing of first cleavage on in vitro developmental potential of nuclear-transferred bovine oocytes receiving cumulus and fibroblast cells.

PubMed

Amarnath, Dasari; Kato, Yoko; Tsunoda, Yukio

2007-06-01

The aim of the present study was to examine whether cumulus and fibroblast cell nuclear-transferred oocytes, which have high and low potential to develop into normal calves, respectively, are different in terms of in their patterns of timing of first cleavage and in their relationships between timing of first cleavage and in vitro developmental potential. The timing of first cleavage was similar in both types of nuclear-transferred and in vitro fertilized oocytes. More than 86% of the oocytes cleaved within 24 h after activation or in vitro fertilization; these oocytes contributed to more than 98% of the total number of blastocysts in all three groups. The potential of oocytes that cleaved at different intervals to develop into blastocysts differed among the groups. The developmental potential of the cumulus cell nuclear-transferred oocytes and in vitro fertilized oocytes decreased with the increase in time required for cleavage. Fibroblast cell nuclear-transferred oocytes that cleaved at 20 h, an intermediate cleaving time, had higher potential to develop into blastocysts. The results of the present study suggest that the type of donor nucleus used for nuclear transfer affects the timing of first cleavage.

On-line tritium production monitor

DOEpatents

Mihalczo, John T.

1993-01-01

A scintillation optical fiber system for the on-line monitoring of nuclear reactions in an event-by-event manner is described. In the measurement of tritium production one or more optical fibers are coated with enriched .sup.6 Li and connected to standard scintillation counter circuitry. A neutron generated .sup.6 Li(n )T reaction occurs in the coated surface of .sup.6 Li-coated fiber to produce energetic alpha and triton particles one of which enters the optical fiber and scintillates light through the fiber to the counting circuit. The coated optical fibers can be provided with position sensitivity by placing a mirror at the free end of the fibers or by using pulse counting circuits at both ends of the fibers.

On-line tritium production monitor

DOEpatents

Mihalczo, J.T.

1993-11-23

A scintillation optical fiber system for the on-line monitoring of nuclear reactions in an event-by-event manner is described. In the measurement of tritium production one or more optical fibers are coated with enriched {sup 6}Li and connected to standard scintillation counter circuitry. A neutron generated {sup 6}Li(n)T reaction occurs in the coated surface of {sup 6}Li-coated fiber to produce energetic alpha and triton particles one of which enters the optical fiber and scintillates light through the fiber to the counting circuit. The coated optical fibers can be provided with position sensitivity by placing a mirror at the free end of the fibers or by using pulse counting circuits at both ends of the fibers. 5 figures.

Optical Imaging of Ionizing Radiation from Clinical Sources

PubMed Central

Shaffer, Travis M.; Drain, Charles Michael

2016-01-01

Nuclear medicine uses ionizing radiation for both in vivo diagnosis and therapy. Ionizing radiation comes from a variety of sources, including x-rays, beam therapy, brachytherapy, and various injected radionuclides. Although PET and SPECT remain clinical mainstays, optical readouts of ionizing radiation offer numerous benefits and complement these standard techniques. Furthermore, for ionizing radiation sources that cannot be imaged using these standard techniques, optical imaging offers a unique imaging alternative. This article reviews optical imaging of both radionuclide- and beam-based ionizing radiation from high-energy photons and charged particles through mechanisms including radioluminescence, Cerenkov luminescence, and scintillation. Therapeutically, these visible photons have been combined with photodynamic therapeutic agents preclinically for increasing therapeutic response at depths difficult to reach with external light sources. Last, new microscopy methods that allow single-cell optical imaging of radionuclides are reviewed. PMID:27688469

Fiber Optic Communication System For Medical Images

NASA Astrophysics Data System (ADS)

Arenson, Ronald L.; Morton, Dan E.; London, Jack W.

1982-01-01

This paper discusses a fiber optic communication system linking ultrasound devices, Computerized tomography scanners, Nuclear Medicine computer system, and a digital fluoro-graphic system to a central radiology research computer. These centrally archived images are available for near instantaneous recall at various display consoles. When a suitable laser optical disk is available for mass storage, more extensive image archiving will be added to the network including digitized images of standard radiographs for comparison purposes and for remote display in such areas as the intensive care units, the operating room, and selected outpatient departments. This fiber optic system allows for a transfer of high resolution images in less than a second over distances exceeding 2,000 feet. The advantages of using fiber optic cables instead of typical parallel or serial communication techniques will be described. The switching methodology and communication protocols will also be discussed.

Nonlinear and non-Hermitian optical systems applied to the development of filters and optical sensors

NASA Astrophysics Data System (ADS)

Amaro de Faria Júnior, A. C.

2015-09-01

In this work we present a method of investigation of nonlinear optical beams generated from non-Hermitian optical systems1 . This method can be applied in the development of optical filters and optical sensors to process, analyze and choose the passband of the propagation modes of an optical pulse from an non-Hermitian optical system. Non-Hermitian optical systems can be used to develop optical fiber sensors that suppress certain propagation modes of optical pulses that eventually behave as quantum noise. Such systems are described by the Nonlinear Schrödinger-like Equation with Parity-Time (PT) Symmetric Optical Potentials. There are optical fiber sensors that due to high laser intensity and frequency can produce quantum noise, such as Raman and Brillouin scattering. However, the optical fiber, for example, can be designed so that its geometry suppress certain propagation modes of the beam. We apply some results of non- Hermitian optical systems with PT symmetry to simulate optical lattice by a appropriate potential function, which among other applications, can naturally suppress certain propagation modes of an optical beam propagating through a waveguide. In other words, the optical system is modeled by a potential function in the Nonlinear Schrödinger-like Equation that one relates with the geometric aspects of the wave guides and with the optical beam interacting with the waveguide material. The paper is organized as follows: sections 1 and 2 present a brief description about nonlinear optical systems and non-Hermitian optical systems with PT symmetry. Section 3 presents a description of the dynamics of nonlinear optical pulses propagating through optical networks described by a optical potential non-Hermitian. Sections 4 and 5 present a general description of this non-Hermitian optical systems and how to get them from a more general model. Section 6 presents some conclusions and comment and the final section presents the references. Begin the abstract two lines below author names and addresses.

Fabrication and physicochemical characterization of porous composite microgranules with selenium oxyanions and risedronate sodium for potential applications in bone tumors.

PubMed

Kolmas, Joanna; Pajor, Kamil; Pajchel, Lukasz; Przekora, Agata; Ginalska, Grażyna; Oledzka, Ewa; Sobczak, Marcin

2017-01-01

Nanocrystalline hydroxyapatite containing selenite ions (SeHA; 9.6 wt.% of selenium) was synthesized using wet method and subject to careful physicochemical analysis by powder X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, solid-state nuclear magnetic resonance, wavelength dispersive X-ray fluorescence, and inductively coupled plasma optical emission spectrometry. SeHA was then used to develop the selenium-containing hydroxyapatite/alginate (SeHA/ALG) composite granules. Risedronate sodium (RIS) was introduced to the obtained spherical microgranules of a size of about 1.1-1.5 mm in 2 ways: during the granules' preparation (RIS solution added to a suspension of ALG and SeHA), and as a result of SeHA/ALG granules soaking in aqueous RIS solution. The analysis made using 13 C and 31 P cross-polarization magic angle spinning nuclear magnetic resonance confirmed the presence of RIS and its interaction with calcium ions. Then, the release of selenium (inductively coupled plasma optical emission spectrometry) and RIS (high-performance liquid chromatography) from microgranules was examined. Moreover, cytotoxicity of fabricated granules was assessed by MTT test. Selenium release was biphasic: the first stage was short and ascribed to a "burst release" probably from a hydrated surface layer of SeHA crystals, while the next stage was significantly longer and ascribed to a sustained release of selenium from the crystals' interior. The study showed that the method of obtaining microgranules containing RIS significantly affects its release profile. Performed cytotoxicity test revealed that fabricated granules had high antitumor activity against osteosarcoma cells. However, because of the "burst release" of selenium during the first 10 h, the granules significantly reduced viability of normal osteoblasts as well.

Uncertainty quantification for optical model parameters

DOE PAGES

Lovell, A. E.; Nunes, F. M.; Sarich, J.; ...

2017-02-21

Although uncertainty quantification has been making its way into nuclear theory, these methods have yet to be explored in the context of reaction theory. For example, it is well known that different parameterizations of the optical potential can result in different cross sections, but these differences have not been systematically studied and quantified. The purpose of our work is to investigate the uncertainties in nuclear reactions that result from fitting a given model to elastic-scattering data, as well as to study how these uncertainties propagate to the inelastic and transfer channels. We use statistical methods to determine a best fitmore » and create corresponding 95% confidence bands. A simple model of the process is fit to elastic-scattering data and used to predict either inelastic or transfer cross sections. In this initial work, we assume that our model is correct, and the only uncertainties come from the variation of the fit parameters. Here, we study a number of reactions involving neutron and deuteron projectiles with energies in the range of 5–25 MeV/u, on targets with mass A=12–208. We investigate the correlations between the parameters in the fit. The case of deuterons on 12C is discussed in detail: the elastic-scattering fit and the prediction of 12C(d,p) 13C transfer angular distributions, using both uncorrelated and correlated χ 2 minimization functions. The general features for all cases are compiled in a systematic manner to identify trends. This work shows that, in many cases, the correlated χ 2 functions (in comparison to the uncorrelated χ 2 functions) provide a more natural parameterization of the process. These correlated functions do, however, produce broader confidence bands. Further optimization may require improvement in the models themselves and/or more information included in the fit.« less

The structure and function of the macula in patients with advanced retinitis pigmentosa.

PubMed

Vámos, Rita; Tátrai, Erika; Németh, János; Holder, Graham E; DeBuc, Delia Cabrera; Somfai, Gábor Márk

2011-10-28

To assess the structure and function of the macula in advanced retinitis pigmentosa (RP). Twenty-nine eyes of 22 patients with RP were compared against 17 control eyes. Time-domain optical coherence tomography (OCT) data were processed using OCTRIMA (optical coherence tomography retinal image analysis) as a means of quantifying commercial OCT system images. The thickness of the retinal nerve fiber layer (RNFL), ganglion cell layer and inner plexiform layer complex (GCL+IPL), inner nuclear layer and outer plexiform layer complex (INL+OPL), and the outer nuclear layer (ONL) were measured. Multifocal electroretinography (mfERG) was performed; two groups were formed based on the mfERG findings. Fourteen eyes had no detectable central retinal function (NCRF) on mfERG; detectable but abnormal retinal function (DRF) was present in the mfERG of the other 15 eyes. The thickness of the ONL in the central macular region was significantly less in the NCRF eyes compared with that in both DRF eyes and controls. The ONL was significantly thinner in the pericentral region in both patient groups compared with that in controls, whereas the thickness of the GCL+IPL and INL+OPL was significantly decreased only in the NCRF eyes. The RNFL in the peripheral region was significantly thicker, whereas the thickness of the GCL+IPL and ONL was significantly thinner in both patient groups compared with that in controls. The results are consistent with degeneration of the outer retina preceding inner retinal changes in RP. OCT image segmentation enables objective evaluation of retinal structural changes in RP, with potential use in the planning of therapeutic interventions and conceivably as an outcome measure.

The Structure and Function of the Macula in Patients with Advanced Retinitis Pigmentosa

PubMed Central

Vámos, Rita; Tátrai, Erika; Németh, János; Holder, Graham E.; DeBuc, Delia Cabrera

2011-01-01

Purpose. To assess the structure and function of the macula in advanced retinitis pigmentosa (RP). Methods. Twenty-nine eyes of 22 patients with RP were compared against 17 control eyes. Time-domain optical coherence tomography (OCT) data were processed using OCTRIMA (optical coherence tomography retinal image analysis) as a means of quantifying commercial OCT system images. The thickness of the retinal nerve fiber layer (RNFL), ganglion cell layer and inner plexiform layer complex (GCL+IPL), inner nuclear layer and outer plexiform layer complex (INL+OPL), and the outer nuclear layer (ONL) were measured. Multifocal electroretinography (mfERG) was performed; two groups were formed based on the mfERG findings. Fourteen eyes had no detectable central retinal function (NCRF) on mfERG; detectable but abnormal retinal function (DRF) was present in the mfERG of the other 15 eyes. Results. The thickness of the ONL in the central macular region was significantly less in the NCRF eyes compared with that in both DRF eyes and controls. The ONL was significantly thinner in the pericentral region in both patient groups compared with that in controls, whereas the thickness of the GCL+IPL and INL+OPL was significantly decreased only in the NCRF eyes. The RNFL in the peripheral region was significantly thicker, whereas the thickness of the GCL+IPL and ONL was significantly thinner in both patient groups compared with that in controls. Conclusions. The results are consistent with degeneration of the outer retina preceding inner retinal changes in RP. OCT image segmentation enables objective evaluation of retinal structural changes in RP, with potential use in the planning of therapeutic interventions and conceivably as an outcome measure. PMID:21948552

Optically Stimulated Luminescence Response to Ionizing Radiation of Red Bricks (SiO2, Al2O3, and Fe2O3) Used as Building Materials

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

Bogard, James S; Espinosa Garcia, Guillermo

2007-01-01

Quartz is the most common mineral in our environment. It is found in granite, hydrothermal veins and volcanic rocks, as well as in sedimentary deposits derived from such solid materials. These sediments are also made into building materials, such as bricks and pottery. Thus the potential use of a dose reconstruction technique based on quartz grains is enormous, whether as a dating tool in archaeology and quaternary geology, or in nuclear accident dosimetry. This work describes the Optically Stimulated Luminescence (OSL) response of red brick to ionizing radiation. The bricks, from the state of Puebla, Mexico, represent another class ofmore » materials that can be used in retrospective dosimetry following nuclear or radiological incidents. The chemical composition of fifteen bricks (three samples from five different brick factories) was determined, using energy dispersive spectroscopy (EDS), be primarily SiO{sub 2}, Al{sub 2}O{sub 3} and Fe{sub 2}O{sub 3} and is believed to be representative for this common building material. Individual aliquots from these bricks were powdered in agate mortars and thermally annealed. Replicate samples of the aliquots were then irradiated with beta particles from a sealed source of {sup 90}Sr/{sup 90}Y. The OSL response was measured with a Daybreak Model 2200 High-Capacity OSL Reader System. We present here for this material the characteristic OSL response to beta particles; the reproducibility of the OSL response; the linearity of the response in the dose range 0.47 Gy to 47 Gy; and the fading characteristics.« less

Fabrication and physicochemical characterization of porous composite microgranules with selenium oxyanions and risedronate sodium for potential applications in bone tumors

PubMed Central

Kolmas, Joanna; Pajor, Kamil; Pajchel, Lukasz; Przekora, Agata; Ginalska, Grażyna; Oledzka, Ewa; Sobczak, Marcin

2017-01-01

Nanocrystalline hydroxyapatite containing selenite ions (SeHA; 9.6 wt.% of selenium) was synthesized using wet method and subject to careful physicochemical analysis by powder X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, solid-state nuclear magnetic resonance, wavelength dispersive X-ray fluorescence, and inductively coupled plasma optical emission spectrometry. SeHA was then used to develop the selenium-containing hydroxyapatite/alginate (SeHA/ALG) composite granules. Risedronate sodium (RIS) was introduced to the obtained spherical microgranules of a size of about 1.1–1.5 mm in 2 ways: during the granules’ preparation (RIS solution added to a suspension of ALG and SeHA), and as a result of SeHA/ALG granules soaking in aqueous RIS solution. The analysis made using 13C and 31P cross-polarization magic angle spinning nuclear magnetic resonance confirmed the presence of RIS and its interaction with calcium ions. Then, the release of selenium (inductively coupled plasma optical emission spectrometry) and RIS (high-performance liquid chromatography) from microgranules was examined. Moreover, cytotoxicity of fabricated granules was assessed by MTT test. Selenium release was biphasic: the first stage was short and ascribed to a “burst release” probably from a hydrated surface layer of SeHA crystals, while the next stage was significantly longer and ascribed to a sustained release of selenium from the crystals’ interior. The study showed that the method of obtaining microgranules containing RIS significantly affects its release profile. Performed cytotoxicity test revealed that fabricated granules had high antitumor activity against osteosarcoma cells. However, because of the “burst release” of selenium during the first 10 h, the granules significantly reduced viability of normal osteoblasts as well. PMID:28848343

Understanding Alterations in Cell Nano-architecture during Early Carcinogenesis using Optical Microscopy

NASA Astrophysics Data System (ADS)

Damania, Dhwanil

Carcinogenesis is a complex multi-step process which eventually results in a malignant phenotype that often progresses into a fatal metastatic stage. There are several molecular changes (e.g. DNA methylation, activation of proto-oncogenes, loss of tumor-suppressor genes, histone acetylation) that occur in cells prior to the microscopically detectable morphological alterations. Hence, it is intuitive that these molecular changes should impact various biochemical, biophysical and transport processes within the cell and therefore its nanoscale morphology. Furthermore, recent studies have established that apparently `normal' cells (i.e., away from the actual tumor location) undergo similar genetic/epigenetic changes as the actual cancer cells, giving rise to the phenomenon of field carcinogenesis. Unfortunately, traditional microscopy or histopathology cannot resolve structures below 300 nm due to diffraction-limited resolution. Hence, we developed a novel optical imaging technique, partial wave spectroscopic (PWS) microscopy or optical nanocytology which quantifies the nanoscale refractive-index fluctuations (i.e. mass-density variations such as chromatin compaction) in an optically measured biomarker, disorder strength (Ld). This dissertation proves the nanoscale sensitivity of PWS nanocytology and shows that increase in Ld parallels neoplastic potential of a cell by using standardized cell-lines and animal-models. Based on concept of field carcinogenesis, we employ PWS nanocytology in a multi-center clinical study on approximately 450 patients in four different cancer-types (colon, ovarian, thyroid and lung) and we illustrate that nanoscale disorder increase is a ubiquitous phenomenon across different organs. We further demonstrate the potential of PWS nanocytology in predicting risk for developing future neoplasia. Biologically, we prove that cytoskeletal organization in both nucleus and cytoplasm plays a crucial role in governing L d-differences. Moreover, we elucidate the role of chromatin architecture (specifically histone deacetylase2) in determining nanoscale nuclear disorder. Finally, we develop an image-analysis technique to extract native 3-dimensional-mass-density correlation function of biological cells (cheek cells) using scanning transmission electron microscopy (STEM) without staining or sectioning. This technique can be used in future to corroborate PWS results. Overall, this work signifies the potential of PWS nanocytology in a clinical setting and establishes it as an important minimally-invasive tool for early cancer detection as well as for better biological understanding of a disease.

Investigation of total cross sections for reactions induced by {sup 6}He interaction with silicon nuclei at energies between 5 and 50 MeV/A

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

Kabdrakhimova, G. D., E-mail: gaukharkd@gmail.com; Sobolev, Yu. G.; Kuhtina, I. N.

2017-01-15

Experimental excitation functions in terms of the total cross sections for {sup 6}He + Si nuclear reactions are analyzed in the energy range between 5 and 50 MeV/A, and a brief survey of the procedures used to obtain experimental data is given. Particular attention is given to describing experiments performed in beams of radioactive nuclei from the accelerators of the Laboratory of Nuclear Reactions at the Joint Institute for Nuclear Research (JINR, Dubna). The experimental data in question are analyzed on the basis of a semimicroscopic optical model.

Planetary camera observations of the double nucleus of M31

NASA Technical Reports Server (NTRS)

Lauer, Tod R.; Faber, S. M.; Groth, Edward J.; Shaya, Edward J.; Campbell, Bel; Code, Arthur; Currie, Douglas G.; Baum, William A.; Ewald, S. P.; Hester, J. J.

1993-01-01

HST Planetary Camera images obtained in the V and I band for M31 show its inner nucleus to consist of two components that are separated by 0.49 arcsec. The nuclear component with lower surface brightness closely coincides with the bulge photocenter and is argued to be at the kinematic center of the galaxy. It is surmised that, if dust absorption generates the asymmetric nuclear morphology observed, the dust grain size must either be exceptionally large, or the dust optical depth must be extremely high; the higher surface-brightness and off-center nuclear component may alternatively be a separate stellar system.

Apatite glass-ceramics: a review

NASA Astrophysics Data System (ADS)

Duminis, Tomas; Shahid, Saroash; Hill, Robert Graham

2016-12-01

This article is a review of the published literature on apatite glass-ceramics (GCs). Topics covered include crystallization mechanisms of the various families of the apatite GCs and an update on research and development on apatite GCs for applications in orthopedics, dentistry, optoelectronics and nuclear waste management. Most apatite GCs crystallize through a homogenous nucleation and crystallization mechanism, which is aided by a prior liquid-liquid phase separation. Careful control of the base glass composition and heat-treatment conditions, which determine the nature and morphology of the crystal phases in the GC can produce GC materials with exceptional thermal, mechanical, optical and biological properties. The GCs reviewed for orthopedic applications exhibit suitable mechanical properties and can chemically bond to bone and stimulate its regeneration. The most commercially successful apatite GCs are those developed for dental veneering. These materials exhibit excellent translucency and clinical esthetics, and mimic the natural tooth mineral. Due to the ease of solid solution of the apatite lattice, rare earth doped apatite GCs are discussed for potential applications in optoelectronics and nuclear waste management. One of the drawbacks of the commercial apatite GCs used in orthopedics is the lack of resorbability, therefore the review provides a direction for future research in the field.

Pressure Effect on Hydrogen Tunneling and Vibrational Spectrum in α-Mn

NASA Astrophysics Data System (ADS)

Kolesnikov, Alexander; Podlesnyak, Andrey; Sadykov, Ravil; Antonov, Vladimir; Kuzovnikov, Michail; Ehlers, Georg; Granroth, Garrett

The pressure effect on the tunneling mode and vibrational spectra of hydrogen in α-MnH0.07 has been studied by inelastic neutron scattering. Applying hydrostatic pressure of up to 30 kbar is shown to shift both the hydrogen optical modes and the tunneling peak to higher energies. First-principles calculations show that the potential for hydrogen in α-Mn becomes overall steeper with increasing pressure. At the same time, the barrier height and its extent in the direction of tunneling decrease and the calculations predict significant changes of the dynamics of hydrogen in α-Mn at 100 kbar, when the estimated tunneling splitting of the hydrogen ground state exceeds the barrier height. Acknowledgments: Research at ORNL SNS was supported by the Sci. User Facilities Division, Office BES, US DOE, and was sponsored by the LDRD Program of ORNL, managed by UT-Battelle, LLC, for the US DOE. It used resources of the Nat. Energy Res. Sci. Comp. Center, which is supported by the Office of Sci. US DOE under Contract No. DE-AC02-05CH11231. A support by a Grant of the Program on Elementary Particle Physics, Fundamental Nuclear Physics and Nuclear Techn. RAS is also acknowledged.

China’s Ace in the Hole Rare Earth Elements

DTIC Science & Technology

2010-01-01

before losing magnetism. 11 Europium sesquioxide (Eu203) has been tested as neutron absorbers for control rods in (fast breeder ) nuclear reactors ...sources of rare earth around the world, it could take anywhere from 10 to 15 years from the time of discovery to begin a full- scale rare earth...television/computer screens, it is being studied for possible use in nuclear reactors .11 Erbium is used as an amplifier for fiber optic data

X-ray comb generation from nuclear-resonance-stabilized x-ray free-electron laser oscillator for fundamental physics and precision metrology

DOE PAGES

Adams, B.  W.; Kim, K. -J.

2015-03-31

An x-ray free-electron laser oscillator (XFELO) is a next-generation x-ray source, similar to free-electron laser oscillators at VUV and longer wavelengths but using crystals as high-reflectivity x-ray mirrors. Each output pulse from an XFELO is fully coherent with high spectral purity. The temporal coherence length can further be increased drastically, from picoseconds to microseconds or even longer, by phase-locking successive XFELO output pulses, using the narrow nuclear resonance lines of nuclei such as ⁵⁷Fe as a reference. We show that the phase fluctuation due to the seismic activities is controllable and that due to spontaneous emission is small. The fluctuationmore » of electron-bunch spacing contributes mainly to the envelope fluctuation but not to the phase fluctuation. By counting the number of standing-wave maxima formed by the output of the nuclear-resonance-stabilized (NRS) XFELO over an optically known length, the wavelength of the nuclear resonance can be accurately measured, possibly leading to a new length or frequency standard at x-ray wavelengths. A NRS-XFELO will be an ideal source for experimental x-ray quantum optics as well as other fundamental physics. The technique can be refined for other, narrower resonances such as ¹⁸¹Ta or ⁴⁵Sc.« less

Velocimetry Overview for visitors from the DOD

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

Briggs, Matthew E.; Holtkamp, David Bruce

2016-08-19

We are in the midst of a transformative period in which technological advances are making fundamental changes in the measurement techniques that form the backbone of nuclear weapon certification. Optical velocimetry has replaced electrical shorting pins in “Hydrotests,” which measure the dynamic implosion process. This advance has revolutionized nuclear weapons certification during the last 5 years. We can now measure the implosion process that drives a nuclear detonation with many orders of magnitude more resolution in both space and time than was possible just 10 years ago. It has been compared to going from Morse Code to HDTV, resulting inmore » a dozen or more improvements in models of these weapons. These Hydrotests are carried out at LANL, LLNL and the NNSS, with the later holding the important role of allowing us to test with nuclear materials, in sub-critical configurations (i.e., no yield.) Each of these institutions has largely replaced pins with hundreds of channels of optical velocimetry. Velocimetry is non-contact and is used simultaneously with the X-ray capability of these facilities. The U1-a facility at NNSS pioneered this approach in the Gemini series in 2012, and continues to lead, both in channel count and technological advances. Close cooperation among LANL, LLNL and NSTec in these advances serves the complex by leveraging capabilities across sites and accelerating the pace of technical improvements.« less

[CHROMATIN ORGANIZATION IN CELL CYCLE OF AMOEBA PROTEUS ACCORDING TO OPTICAL TOMOGRAPHY DATA].

PubMed

Demin, S Yu; Berdieva, M A; Podlipaeva, Yu I; Yudin, A L; Goodkov, A V

2015-01-01

For the first time the nuclear cycle of large freshwater amoeba Amoeba proteus was studied by the method of optical tomography. The nuclei were fixed in situ in the cells of synchronized culture, stained by DAPI and examined by confocal laser scanning microscope. 3D-images of intranuclear chromatin were studied in details at different stages of nuclear cycle. The obtained data, together with literary ones allow represent the dynamics of structural organization of the nucleus in Amoeba proteus cell cycle in a new fashion. It was concluded that in this species the two-stage interphase takes place, as well as mitosis of peculiar type which does not correspond to any known type of mitosis according to classification existing now. It is presumed that in the course of nuclear cycle the chromosomes and/or their fragments are amplified, this presumption being in a good correspondence with the data about nuclear DNA hyperreplication in the cell cycle of A. proteus. As a result of chromosomes amplification their number may vary at different stages of cell cycle, and it allows to explain the contradictory data concerning the exact number of chromosomes in this species. The elimination of extra-DNA occurs mainly at the stage between prophase and prometaphase. We presume the majority of chromosomes, or may be even all of them to be referred to cholocentric type according to their behaviour during the mitosis.

OWL: A code for the two-center shell model with spherical Woods-Saxon potentials

NASA Astrophysics Data System (ADS)

Diaz-Torres, Alexis

2018-03-01

A Fortran-90 code for solving the two-center nuclear shell model problem is presented. The model is based on two spherical Woods-Saxon potentials and the potential separable expansion method. It describes the single-particle motion in low-energy nuclear collisions, and is useful for characterizing a broad range of phenomena from fusion to nuclear molecular structures.

Ultraviolet observations of clusters of Wolf-Rayet stars in the SBm3 galaxy NGC 4214 and Ultraviolet and optical observations of LINER's

NASA Technical Reports Server (NTRS)

Filippenko, Alexei V.

1992-01-01

The purpose of the grant was to obtain and analyze IUE (UV) and ground-based (optical) spectra of the central bar of NGC 4214, which contains several bright H II regions, in order to further explore the properties of the Wolf-Rayet stars in this galaxy. Several spatially distinct regions, with widely different equivalent widths of optical Wolf-Rayet lines, could be sampled by the large IUE entrance aperture. By using newly developed extraction techniques, the spectra of these H II regions could be isolated, and differences in their stellar populations would be systematically studied. Data were obtained with IUE in late February and early March, 1992. Some of the shifts were successful, but a few were not -- apparently the blind offset from the nearby star did not work equally well in all cases. Thus, the signal-to-noise ratio is somewhat lower than we had hoped. This necessitated a more careful extraction of the spectra of individual H II regions from the two-dimensional spectra. (A program that models the point spread function in the spatial direction was used to deblend the distinct H II regions.) The IUE data are currently being analyzed in conjunction with ground-based optical spectra. There appear to be obvious variations in the stellar population over angular scales of only a few arc seconds. The second part of the research performed under this grant was a continuation of a project that uses IUE (UV) and ground-based (optical) spectra to infer the physical conditions in Low-Ionization Nuclear Emission-Line Regions (LINER's). We have obtained spectra of a few key objects that cover a representative range in LINER continuum and emission-line properties. The overall goals are to (1) separate the emission into spatially distinct components, (2) establish whether the observed nuclear ultraviolet continua indicate sufficient photoionizing fluxes to account for the emission lines, (3) determine whether the nuclear emission can be explained by hot stars alone, (4) detect and measure the strengths of UV emission lines, and (5) search for systematic differences in the UV spectra of LINER's whose other properties differ in some respects.

General theory of feedback control of a nuclear spin ensemble in quantum dots

NASA Astrophysics Data System (ADS)

Yang, Wen; Sham, L. J.

2013-12-01

We present a microscopic theory of the nonequilibrium nuclear spin dynamics driven by the electron and/or hole under continuous-wave pumping in a quantum dot. We show the correlated dynamics of the nuclear spin ensemble and the electron and/or hole under optical excitation as a quantum feedback loop and investigate the dynamics of the many nuclear spins as a nonlinear collective motion. This gives rise to three observable effects: (i) hysteresis, (ii) locking (avoidance) of the pump absorption strength to (from) the natural resonance, and (iii) suppression (amplification) of the fluctuation of weakly polarized nuclear spins, leading to prolonged (shortened) electron-spin coherence time. A single nonlinear feedback function is constructed which determines the different outcomes of the three effects listed above depending on the feedback being negative or positive. The general theory also helps to put in perspective the wide range of existing theories on the problem of a single electron spin in a nuclear spin bath.

Global optical model potential for A=3 projectiles

NASA Astrophysics Data System (ADS)

Pang, D. Y.; Roussel-Chomaz, P.; Savajols, H.; Varner, R. L.; Wolski, R.

2009-02-01

A global optical model potential (GDP08) for He3 projectiles has been obtained by simultaneously fitting the elastic scattering data of He3 from targets of 40⩽AT⩽209 at incident energies of 30⩽Einc⩽217 MeV. Uncertainties and correlation coefficients between the global potential parameters were obtained by using the bootstrap statistical method. GDP08 was found to satisfactorily account for the elastic scattering of H3 as well, which makes it a global optical potential for the A=3 nuclei. Optical model calculations using the GDP08 global potential are compared with the experimental angular distributions of differential cross sections for He3-nucleus and H3-nucleus scattering from different targets of 6⩽AT⩽232 at incident energies of 4⩽Einc⩽450 MeV. The optical potential for the doubly-magic nucleus Ca40, the low-energy correction to the real potential for nuclei with 58≲AT≲120 at Einc<30 MeV, the comparison with double-folding model calculations and the CH89 potential, and the spin-orbit potential parameters are discussed.

Evaluation of neutron total and capture cross sections on 99Tc in the unresolved resonance region

NASA Astrophysics Data System (ADS)

Iwamoto, Nobuyuki; Katabuchi, Tatsuya

2017-09-01

Long-lived fission product Technetium-99 is one of the most important radioisotopes for nuclear transmutation. The reliable nuclear data are indispensable for a wide energy range up to a few MeV, in order to develop environmental load reducing technology. The statistical analyses of resolved resonances were performed by using the truncated Porter-Thomas distribution, coupled-channels optical model, nuclear level density model and Bayes' theorem on conditional probability. The total and capture cross sections were calculated by a nuclear reaction model code CCONE. The resulting cross sections have statistical consistency between the resolved and unresolved resonance regions. The evaluated capture data reproduce those recently measured at ANNRI of J-PARC/MLF above resolved resonance region up to 800 keV.

Ultraviolet to optical spectral distributions of northern star-forming galaxies

NASA Technical Reports Server (NTRS)

Mcquade, Kerry; Calzetti, Daniela; Kinney, Anne L.

1995-01-01

We report spectral energy distribution from the UV to the optical for a sample of 31 northern star-forming galaxies. We also present measurements for emission-line fluxes, continuum levels, and equivalent widths of absorption features for each individual spectrum as well as averages for the eight galactic activity classes, including normal, starburst, Seyfert 2, blue compact dwarf, blue compact, Low-Inonization Nuclear Emission Regions (LINER), H II, and combination LINER-H II galaxies.

Fiber-optic laser-induced breakdown spectroscopy of zirconium metal in air: Special features of the plasma produced by a long-pulse laser

NASA Astrophysics Data System (ADS)

Matsumoto, Ayumu; Ohba, Hironori; Toshimitsu, Masaaki; Akaoka, Katsuaki; Ruas, Alexandre; Sakka, Tetsuo; Wakaida, Ikuo

2018-04-01

The decommissioning of the Tokyo Electric Power Company (TEPCO) Fukushima Daiichi Nuclear Power Plant is an essential issue in nuclear R&D. Fiber-optic laser-induced breakdown spectroscopy (Fiber-optic LIBS) could be used for in-situ elemental analysis of the inside of the damaged reactors. To improve the performances under difficult conditions, using a long-pulse laser can be an efficient alternative. In this work, the emission spectra of zirconium metal in air obtained for a normal-pulse laser (6 ns) and a long-pulse laser (100 ns) (wavelength: 1064 nm, pulse energy: 12.5 mJ, spot diameter: 0.35 mm) are compared to investigate the fundamental aspects of fiber-optic LIBS with the long-pulse laser. The spectral features are considerably different: when the long-pulse laser is used, the atomic and molecular emission is remarkably enhanced. The enhancement of the atomic emission at the near infrared (NIR) region would lead to the observation of emission lines with minimum overlapping. To understand the differences in the spectra induced respectively from the normal-pulse laser and the long-pulse laser, photodiode signals, time-resolved spectra, plasma parameters, emission from the ambient air, and emission regions are investigated, showing the particular characteristics of the plasma produced by the long-pulse laser.

Quantum Control and Entanglement of Spins in Silicon Carbide

NASA Astrophysics Data System (ADS)

Klimov, Paul

Over the past several decades silicon carbide (SiC) has matured into a versatile material platform for high-power electronics and optoelectronic and micromechanical devices. Recent advances have also established SiC as a promising host for quantum technologies based on the spin of intrinsic defects, with the potential of leveraging existing device fabrication protocols alongside solid-state quantum control. Among these defects are the divacancies and related color centers, which have ground-state electron-spin triplets with coherence times as long as one millisecond and built-in optical interfaces operating near the telecommunication wavelengths. This rapidly developing field has prompted research into the SiC material host to understand how defect-bound electron spins interact with their surrounding nuclear spin bath. Although nuclear spins are a major source of decoherence in color-center spin systems, they are also a valuable resource since they can have coherence times that are orders of magnitude longer than electron spins. In this talk I will discuss our recent efforts to interface defect-bound electron spins in SiC with the nuclear spins of naturally occurring 29Si and 13C isotopic defects. I will discuss how the hyperfine interaction can be used to strongly initialize them, to coherently control them, to read them out, and to produce genuine electron-nuclear ensemble entanglement, all at ambient conditions. These demonstrations motivate further research into spins in SiC for prospective quantum technologies. In collaboration with A. Falk, D. Christle, K. Miao, H. Seo, V. Ivady, A. Gali, G. Galli, and D. D. Awschalom. This research was supported by the AFOSR, the NSF DMR-1306300, and the NSF Materials Research Science and Engineering Center.

High-fidelity spin measurement on the nitrogen-vacancy center

NASA Astrophysics Data System (ADS)

Hanks, Michael; Trupke, Michael; Schmiedmayer, Jörg; Munro, William J.; Nemoto, Kae

2017-10-01

Nitrogen-vacancy (NV) centers in diamond are versatile candidates for many quantum information processing tasks, ranging from quantum imaging and sensing through to quantum communication and fault-tolerant quantum computers. Critical to almost every potential application is an efficient mechanism for the high fidelity readout of the state of the electronic and nuclear spins. Typically such readout has been achieved through an optically resonant fluorescence measurement, but the presence of decay through a meta-stable state will limit its efficiency to the order of 99%. While this is good enough for many applications, it is insufficient for large scale quantum networks and fault-tolerant computational tasks. Here we explore an alternative approach based on dipole induced transparency (state-dependent reflection) in an NV center cavity QED system, using the most recent knowledge of the NV center’s parameters to determine its feasibility, including the decay channels through the meta-stable subspace and photon ionization. We find that single-shot measurements above fault-tolerant thresholds should be available in the strong coupling regime for a wide range of cavity-center cooperativities, using a majority voting approach utilizing single photon detection. Furthermore, extremely high fidelity measurements are possible using weak optical pulses.

Precision measurement of the positron asymmetry of laser-cooled, spin-polarized 37K

NASA Astrophysics Data System (ADS)

Melconian, Dan; Fenker, B.; Behr, J. A.; Anholm, M.; Ashery, D.; Behling, R. S.; Cohen, I.; Craiciu, I.; Gorelov, A.; Gwinner, G.; McNeil, J.; Mehlman, M.; Smale, S.; Warner, C. L.

2017-01-01

Precision low-energy measurements in nuclear β decay can be used to provide constraints on possible physics beyond the standard model, complementing searches at high-energy colliders. The short-lived isotope 37K was produced at ISAC-TRIUMF and confined in an alternating magneto-optical trap before being spin-polarized to 99.13(9)% via optical pumping. Our system allows for an exceptionally open geometry with the decay products escaping with their momenta unperturbed by the shallow trapping potential. The emitted positrons are detected in a pair of symmetric detectors placed along the polarization axis to measure the β asymmetry. The analysis was performed blind and considers β-scattering as well as other systematic effects. The results place limits on the mass of a hypothetical W boson coupling to right-handed neutrinos as well as contribute to an independent determination of the Vud element of the CKM matrix. The β asymmetry result as well as improvements and future plans will be described. This work is supported in part by the U.S. Department of Energy, the Natural Sciences and Engineering Research Council of Canada, and the Israel Science Foundation.

Fibre optic confocal imaging (FOCI) of keratinocytes, blood vessels and nerves in hairless mouse skin in vivo

PubMed Central

BUSSAU, L. J.; VO, L. T.; DELANEY, P. M.; PAPWORTH, G. D.; BARKLA, D. H.; KING, R. G.

1998-01-01

Fibre optic confocal imaging (FOCI) enabled subsurface fluorescence microscopy of the skin of hairless mice in vivo. Application of acridine orange enabled imaging of the layers of the epidermis. The corneocytes of the stratum corneum, the keratinocytes in the basal layers and redundant hair follicles were visualised at depths greater than 100 μm. Cellular and nuclear membranes of keratinocytes of the skin were visualised by the use of acridine orange and DIOC5(3). Imaging of the skin after injection of FITC-dextran revealed an extensive network of blood vessels with a size range up to 20 μm. Blood cells could be seen moving through dermal vessels and the blood circulation through the dermal vascular bed was video-taped. The fluorescent dye 4-di-2-ASP showed the presence of nerves fibres around the hair follicles and subsurface blood vessels. Comparison was made between images obtained in vivo using FOCI and in vitro scanning electron microscopy and conventional histology. FOCI offers the potential to study dynamic events in vivo, such as blood flow, skin growth, nerve regeneration and many pathological processes, in ways which have not previously been possible. PMID:9643419

Automated seeding-based nuclei segmentation in nonlinear optical microscopy.

PubMed

Medyukhina, Anna; Meyer, Tobias; Heuke, Sandro; Vogler, Nadine; Dietzek, Benjamin; Popp, Jürgen

2013-10-01

Nonlinear optical (NLO) microscopy based, e.g., on coherent anti-Stokes Raman scattering (CARS) or two-photon-excited fluorescence (TPEF) is a fast label-free imaging technique, with a great potential for biomedical applications. However, NLO microscopy as a diagnostic tool is still in its infancy; there is a lack of robust and durable nuclei segmentation methods capable of accurate image processing in cases of variable image contrast, nuclear density, and type of investigated tissue. Nonetheless, such algorithms specifically adapted to NLO microscopy present one prerequisite for the technology to be routinely used, e.g., in pathology or intraoperatively for surgical guidance. In this paper, we compare the applicability of different seeding and boundary detection methods to NLO microscopic images in order to develop an optimal seeding-based approach capable of accurate segmentation of both TPEF and CARS images. Among different methods, the Laplacian of Gaussian filter showed the best accuracy for the seeding of the image, while a modified seeded watershed segmentation was the most accurate in the task of boundary detection. The resulting combination of these methods followed by the verification of the detected nuclei performs high average sensitivity and specificity when applied to various types of NLO microscopy images.

Development of Selective Excitation Methods in Nuclear Magnetic Resonance: Investigation of Hemoglobin Oxygenation in Erythrocytes Using Proton and Phosphorus -31 Nuclear Magnetic Resonance

NASA Astrophysics Data System (ADS)

Fetler, Bayard Keith

1993-01-01

Nuclear magnetic resonance (NMR) offers a potential method for making measurements of the percent oxygenation of hemoglobin (Hb) in living tissue non-invasively. As a demonstration of the feasibility of such measurements, we measured the percent oxygenation of Hb in red blood cells (erythrocytes) using resonances in the proton-NMR (^1H-NMR) spectrum which are characteristic of oxyhemoglobin (oxy-Hb) and deoxyhemoglobin (deoxy-Hb), and are due to the unique magnetic properties of these molecules. To perform these measurements, we developed a new NMR method of selectively exciting signals in a region of interest with uniform phase and amplitude, while suppressing the signal of the water resonance. With this method, we are able to make exact calculations distinguishing between uniform phase excitation produced at large flip-angles using the non-linear properties of the Bloch equations, and uniform phase excitation produced at small flip-angles using asymmetric pulse excitation functions. We measured the percent oxygenation of three characteristic ^1H-NMR resonances of Hb: two from deoxy-Hb, originating from the N_delta H protons of histidine residue F8, which occur at different frequencies for the alpha and beta chains of Hb; and one from oxy-Hb, originating from the gamma_2 -CH_3 protons of valine residue E11. We performed experiments both on fresh erythrocytes and on erythrocytes depleted of 2,3-diphosphoglycerate (2,3-DPG), and found that oxygen is more tightly bound to Hb in the former case. In both fresh and 2,3-DPG-depleted samples, we found that: (i) from the deoxy-Hb marker resonances, there is a small but significant difference in the oxygen saturation between the alpha and beta chains; (ii) the decrease in the areas of the deoxy-Hb marker resonances correlates well with the increase in the percent oxygenation of Hb as measured optically; (iii) the area of the oxy-Hb marker resonance may be up to ~15% less than the optically measured Hb saturation. We are thus able to demonstrate the feasibility and validity of using this method to measure the oxygen saturation of Hb using ^1H-NMR.

A Tale of Two Comets: ISON

NASA Image and Video Library

2013-11-25

An optical color image of galaxies is seen here overlaid with X-ray data magenta from NASA Nuclear Spectroscopic Telescope Array NuSTAR. Both magenta blobs show X-rays from massive black holes buried at the hearts of galaxies.

Optical spectroscopy of laser-produced plasmas for standoff isotopic analysis

NASA Astrophysics Data System (ADS)

Harilal, S. S.; Brumfield, B. E.; LaHaye, N. L.; Hartig, K. C.; Phillips, M. C.

2018-06-01

Rapid, in-field, and non-contact isotopic analysis of solid materials is extremely important to a large number of applications, such as nuclear nonproliferation monitoring and forensics, geochemistry, archaeology, and biochemistry. Presently, isotopic measurements for these and many other fields are performed in laboratory settings. Rapid, in-field, and non-contact isotopic analysis of solid material is possible with optical spectroscopy tools when combined with laser ablation. Laser ablation generates a transient vapor of any solid material when a powerful laser interacts with a sample of interest. Analysis of atoms, ions, and molecules in a laser-produced plasma using optical spectroscopy tools can provide isotopic information with the advantages of real-time analysis, standoff capability, and no sample preparation requirement. Both emission and absorption spectroscopy methods can be used for isotopic analysis of solid materials. However, applying optical spectroscopy to the measurement of isotope ratios from solid materials presents numerous challenges. Isotope shifts arise primarily due to variation in nuclear charge distribution caused by different numbers of neutrons, but the small proportional nuclear mass differences between nuclei of various isotopes lead to correspondingly small differences in optical transition wavelengths. Along with this, various line broadening mechanisms in laser-produced plasmas and instrumental broadening generated by the detection system are technical challenges frequently encountered with emission-based optical diagnostics. These challenges can be overcome by measuring the isotope shifts associated with the vibronic emission bands from molecules or by using the techniques of laser-based absorption/fluorescence spectroscopy to marginalize the effect of instrumental broadening. Absorption and fluorescence spectroscopy probe the ground state atoms existing in the plasma when it is cooler, which inherently provides narrower lineshapes, as opposed to emission spectroscopy which requires higher plasma temperatures to be able to detect thermally excited emission. Improvements in laser and detection systems and spectroscopic techniques have allowed for isotopic measurements to be carried out at standoff distances under ambient atmospheric conditions, which have expanded the applicability of optical spectroscopy-based isotopic measurements to a variety of scientific fields. These technological advances offer an in-situ measurement capability that was previously not available. This review will focus on isotope detection through emission, absorption, and fluorescence spectroscopy of atoms and molecules in a laser-produced plasma formed from a solid sample. A description of the physics behind isotope shifts in atoms and molecules is presented, followed by the physics behind solid sampling of laser ablation plumes, optical methods for isotope measurements, the suitable physical conditions of laser-produced plasma plumes for isotopic analysis, and the current status. Finally, concluding remarks will be made on the existing knowledge/technological gaps identified from the current literature and suggestions for the future work.

Persistence of uranium emission in laser-produced plasmas

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

LaHaye, N. L.; Harilal, S. S., E-mail: hari@purdue.edu; Diwakar, P. K.

2014-04-28

Detection of uranium and other nuclear materials is of the utmost importance for nuclear safeguards and security. Optical emission spectroscopy of laser-ablated U plasmas has been presented as a stand-off, portable analytical method that can yield accurate qualitative and quantitative elemental analysis of a variety of samples. In this study, optimal laser ablation and ambient conditions are explored, as well as the spatio-temporal evolution of the plasma for spectral analysis of excited U species in a glass matrix. Various Ar pressures were explored to investigate the role that plasma collisional effects and confinement have on spectral line emission enhancement andmore » persistence. The plasma-ambient gas interaction was also investigated using spatially resolved spectra and optical time-of-flight measurements. The results indicate that ambient conditions play a very important role in spectral emission intensity as well as the persistence of excited neutral U emission lines, influencing the appropriate spectral acquisition conditions.« less

Note: Real time optical sensing of alpha-radiation emitting radioactive aerosols based on solid state nuclear track detector.

PubMed

Kulkarni, A; Ha, S; Joshirao, P; Manchanda, V; Bak, M S; Kim, T

2015-06-01

A sensitive radioactive aerosols sensor has been designed and developed. Its design guidance is based on the need for a low operational cost and reliable measurements to provide daily aerosol monitoring. The exposure of diethylene-glycol bis (allylcarbonate) to radiation causes modification of its physico-chemical properties like surface roughness and reflectance. In the present study, optical sensor based on the reflectance measurement has been developed with an aim to monitor real time presence of alpha radioactive aerosols emitted from thorium nitrate hydrate. The results shows that the fabricated sensor can detect 0.0157 kBq to 0.1572 kBq of radio activity by radioactive aerosols generated from (Th(NO3)4 ⋅ 5H2O) at 0.1 ml/min flow rate. The proposed instrument will be helpful to monitor radioactive aerosols in/around a nuclear facility, building construction sites, mines, and granite polishing factories.

Recent optimization of the beam-optical characteristics of the 6 MV van de Graaff accelerator for high brightness beams at the iThemba LABS NMP facility

NASA Astrophysics Data System (ADS)

Conradie, J. L.; Eisa, M. E. M.; Celliers, P. J.; Delsink, J. L. G.; Fourie, D. T.; de Villiers, J. G.; Maine, P. M.; Springhorn, K. A.; Pineda-Vargas, C. A.

2005-04-01

With the aim of improving the reliability and stability of the beams delivered to the nuclear microprobe at iThemba LABS, as well as optimization of the beam characteristics along the van de Graaff accelerator beamlines in general, relevant modifications were implemented since the beginning of 2003. The design and layout of the beamlines were revised. The beam-optical characteristics through the accelerator, from the ion source up to the analysing magnet directly after the accelerator, were calculated and the design optimised, using the computer codes TRANSPORT, IGUN and TOSCA. The ion source characteristics and optimal operating conditions were determined on an ion source test bench. The measured optimal emittance for 90% of the beam intensity was about 50π mm mrad for an extraction voltage of 6 kV. These changes allow operation of the Nuclear Microprobe at proton energies in the range 1 MeV-4 MeV with beam intensities of tenths of a pA at the target surface. The capabilities of the nuclear microprobe facility were evaluated in the improved beamline, with particular emphasis to bio-medical samples.

Qualification of a truly distributed fiber optic technique for strain and temperature measurements in concrete structures

NASA Astrophysics Data System (ADS)

Henault, J. M.; Salin, J.; Moreau, G.; Delepine-Lesoille, S.; Bertand, J.; Taillade, F.; Quiertant, M.; Benzarti, K.

2011-04-01

Structural health monitoring is a key factor in life cycle management of infrastructures. Truly distributed fiber optic sensors are able to provide relevant information on large structures, such as nuclear power plants or nuclear waste disposal facilities. The sensing chain includes an optoelectronic unit and a sensing cable made of one or more optical fibers. A new instrument based on Optical Frequency Domain Reflectometry (OFDR), enables to perform temperature and strain measurements with a centimeter scale spatial resolution over hundred of meters and with a level of precision equal to 1 μ strain and 0.1 °C. Several sensing cables are designed with different materials targeting to last for decades, either embedded in the concrete or attached to the surface of the structure. They must ensure an optimal transfer of temperature and strain from the concrete matrix to the optical fiber. Based on the European guide FD CEN/TR 14748 "Non-destructive testing - Methodology for qualification of non-destructive tests", a qualification method was developed. Tests were carried out using various sensing cables embedded in the volume or fixed to the surface of plain concrete specimens and representative-scale reinforced concrete structural elements. Measurements were performed with an OFDR instrument, while mechanical solicitations were imposed to the concrete element. Preliminary experiments seem very promising since measurements performed with distributed sensing systems are found comparable to values obtained with conventional sensors used in civil engineering and with the Strength of Materials Modelling. Moreover, the distributed sensing system makes it possible to detect and localize cracks appearing in concrete during the mechanical loading.

Elastic neutron scattering studies at 96 MeV for transmutation.

PubMed

Osterlund, M; Blomgren, J; Hayashi, M; Mermod, P; Nilsson, L; Pomp, S; Ohrn, A; Prokofiev, A V; Tippawan, U

2007-01-01

Elastic neutron scattering from (12)C, (14)N, (16)O, (28)Si, (40)Ca, (56)Fe, (89)Y and (208)Pb has been studied at 96 MeV in the10-70 degrees interval, using the SCANDAL (SCAttered Nucleon Detection AssembLy) facility. The results for (12)C and (208)Pb have recently been published, while the data on the other nuclei are under analysis. The achieved energy resolution, 3.7 MeV, is about an order of magnitude better than for any previous experiment above 65 MeV incident energy. A novel method for normalisation of the absolute scale of the cross section has been used. The estimated normalisation uncertainty, 3%, is unprecedented for a neutron-induced differential cross section measurement on a nuclear target. Elastic neutron scattering is of utmost importance for a vast number of applications. Besides its fundamental importance as a laboratory for tests of isospin dependence in the nucleon-nucleon, and nucleon-nucleus, interaction, knowledge of the optical potentials derived from elastic scattering come into play in virtually every application where a detailed understanding of nuclear processes is important. Applications for these measurements are dose effects due to fast neutrons, including fast neutron therapy, as well as nuclear waste incineration and single event upsets in electronics. The results at light nuclei of medical relevance ((12)C, (14)N and (16)O) are presented separately. In the present contribution, results on the heavier nuclei are presented, among which several are of relevance to shielding of fast neutrons.

Identification and Quantitation of Sorbitol-Based Nuclear Clarifying Agents Extracted from Common Laboratory and Consumer Plasticware Made of Polypropylene

PubMed Central

McDonald, Jeffrey G.; Cummins, Carolyn L.; Barkley, Robert M.; Thompson, Bonne M.; Lincoln, Holly A.

2009-01-01

Reported here is the mass spectral identification of sorbitol-based nuclear clarifying agents (NCAs) and the quantitative description of their extractability from common laboratory and household plasticware made of polypropylene. NCAs are frequently added to polypropylene to improve optical clarity, increase performance properties, and aid in the manufacturing process of this plastic. NCA addition makes polypropylene plasticware more aesthetically pleasing to the user and makes the product competitive with other plastic formulations. We show here that several NCAs are readily extracted with either ethanol or water from plastic labware during typical laboratory procedures. Observed levels ranged from a nanogram to micrograms of NCA. NCAs were also detected in extracts from plastic food storage containers; levels ranged from 1to 10 μg in two of the three brands tested. The electron ionization mass spectra for three sorbitol-based nuclear clarifying agents (1,3:2,4-bis-O-(benzylidene)sorbitol, 1,3:2,4-bis-O-(p-methylbenzylidene)sorbitol, 1,3:2,4-bis-O-(3,4-dimethylbenzylidene)sorbitol) are presented for the native and trimethylsilylderivatized compounds together with the collision-induced dissociation mass spectra; gas and liquid chromatographic data are also reported. These NCAs now join other well-known plasticizers such as phthalate esters and bisphenol A as common laboratory contaminants. While the potential toxicity of NCAs in mammalian systems is unknown, the current data provide scientists and consumers the opportunity to make more informed decisions regarding the use of polypropylene plastics. PMID:18533681

Innovations in Nuclear Imaging Instrumentation: Cerenkov Imaging.

PubMed

Tamura, Ryo; Pratt, Edwin C; Grimm, Jan

2018-07-01

Cerenkov luminescence (CL) is blue glow light produced by charged subatomic particles travelling faster than the phase velocity of light in a dielectric medium such as water or tissue. CL was first discovered in 1934, but for biomedical research it was recognized only in 2009 after advances in optical camera sensors brought the required high sensitivity. Recently, applications of CL from clinical radionuclides have been rapidly expanding to include not only preclinical and clinical biomedical imaging but also an approach to therapy. Cerenkov Luminescence Imaging (CLI) utilizes CL generated from clinically relevant radionuclides alongside optical imaging instrumentation. CLI is advantageous over traditional nuclear imaging methods in terms of infrastructure cost, resolution, and imaging time. Furthermore, CLI is a truly multimodal imaging method where the same agent can be detected by two independent modalities, with optical (CL) imaging and with positron emission tomography (PET) imaging. CL has been combined with small molecules, biomolecules and nanoparticles to improve diagnosis and therapy in cancer research. Here, we cover the fundamental breakthroughs and recent advances in reagents and instrumentation methods for CLI as well as therapeutic application of CL. Copyright © 2018 Elsevier Inc. All rights reserved.

Believing Your Eyes: Strengthening the Reliability of Tags and Seals

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

Brim, Cornelia P.; Denlinger, Laura S.

2013-07-01

NNSA’s Office of Nonproliferation and International Security (NIS) is working together with scientific experts at the DOE national laboratories to develop the tools needed to safeguard and secure nuclear material from diversion, theft, and sabotage--tasks critical to support future arms control treaties that may involve the new challenge of monitoring nuclear weapons dismantlement. Use of optically stimulated luminescent material is one method to enhance the security and robustness of existing tamper indicating devices such as tags and seals.

Physics through the 1990s: Atomic, molecular and optical physics

NASA Technical Reports Server (NTRS)

1986-01-01

The volume presents a program of research initiatives in atomic, molecular, and optical physics. The current state of atomic, molecular, and optical physics in the US is examined with respect to demographics, education patterns, applications, and the US economy. Recommendations are made for each field, with discussions of their histories and the relevance of the research to government agencies. The section on atomic physics includes atomic theory, structure, and dynamics; accelerator-based atomic physics; and large facilities. The section on molecular physics includes spectroscopy, scattering theory and experiment, and the dynamics of chemical reactions. The section on optical physics discusses lasers, laser spectroscopy, and quantum optics and coherence. A section elucidates interfaces between the three fields and astrophysics, condensed matter physics, surface science, plasma physics, atmospheric physics, and nuclear physics. Another section shows applications of the three fields in ultra-precise measurements, fusion, national security, materials, medicine, and other topics.

Test and Evaluation of Fiber Optic Sensors for High-Radiation Space Nuclear Power Applications

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

Klemer, Daniel; Fielder, Robert S.; Stinson-Bagby, Kelly L.

2004-07-01

Fiber optic sensors can be used to measure a number of parameters, including temperature, strain, pressure and flow, for instrumentation and control of space nuclear power systems. In the past, this technology has often been rejected for use in such a high-radiation environment based on early experiments that revealed a number of degradation phenomena, including radiation-induced fiber attenuation, or 'graying', and Fiber Bragg Grating (FBG) fading and wavelength shift. However, this paper reports the results of recent experimental testing that demonstrates readability of fiber optic sensors to extremely high levels of neutron and gamma radiation. Both distributed Fiber Bragg Gratingmore » (FBG) sensors and single-point Extrinsic Fabry Perot Interferometer (EFPI) sensors were continuously monitored over a 2-month period, during which they were exposed to combined neutron and gamma radiation in both in-core and ex-core positions within a nuclear reactor. Total exposure reached approximately 2 x 10{sup 19} cm{sup -2} fast neutron (E > 1 MeV) fluence and 8.7 x 10{sup 8} Gy gamma for in-core sensors. FBG sensors were interrogated using a standard Luna Innovations FBG measurement system, which is based on optical frequency-domain reflectometer (OFDR) technology. Approximately 74% of the 19 FBG sensors located at the core centerline in the in-core position exhibited sufficient signal-to-noise ratio (SNR) to remain readable even after receiving the maximum dose. EFPI sensors were spectrally interrogated using a broadband probe source operating in the 830 nm wavelength region. While these single-point sensors failed early in the test, important additional fiber spectral transmission data was collected, which indicates that interrogation of EFPI sensors in alternate wavelength regions may allow significant improvement in sensor longevity for operation in high-radiation environments. This work was funded through a Small Business Innovative Research (SBIR) contract with the Nasa Glenn Research Center. (authors)« less

Development of a video-based slurry sensor for on-line ash analysis. Fifth quarterly technical progress report, October 1, 1995--December 31, 1995

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

Adel, G.T.; Luttrell, G.H.

Automatic control of fine coal cleaning circuits has traditionally been limited by the lack of sensors for on-line ash analysis. Although several nuclear-based analyzers are available, none have seen widespread acceptance. This is largely due to the fact that nuclear sensors are expensive and tend to be influenced by changes in seam type and pyrite content. Recently, researchers at VPI&SU have developed an optical sensor for phosphate analysis. The sensor uses image processing technology to analyze video images of phosphate ore. It is currently being used by PCS Phosphate for off-line analysis of dry flotation concentrate. The primary advantages ofmore » optical sensors over nuclear sensors are that hey are significantly cheaper, are not subject to measurement variations due to changes in high atomic number materials, are inherently safer and require no special radiation permitting. The purpose of this work is to apply the knowledge gained in the development of an optical phosphate analyzer to the development of an on-line ash analyzer for fine coal slurries. During the past quarter, the current prototype of the on-line optical ash analyzer was subjected to extensive testing at the Middlefork coal preparation plant. Initial work focused on obtaining correlations between ash content and mean gray level, while developmental work on the more comprehensive neural network calibration approach continued. Test work to date shows a promising trend in the correlation between ash content and mean gray level. Unfortunately, data scatter remains significant. Recent tests seem to eliminate variations in percent solids, particle size distribution, measurement angle and light setting as causes for the data scatter; however, equipment warm-up time and number of images taken per measurement appear to have a significant impact on the gray-level values obtained. 8 figs., 8 tabs.« less

Women in Physics.

ERIC Educational Resources Information Center

Roth, Laura M.; O'Fallon, Nancy M.

This booklet presents information about career opportunities for women in physics. Included are summaries of research areas in physics (optical physics, solid-state physics, materials science, nuclear physics, high-energy physics, astrophysics, cryogenics, plasma physics, biophysics, atmospheric physics) and differences between theory and…

Skin optical clearing potential of disaccharides

NASA Astrophysics Data System (ADS)

Feng, Wei; Shi, Rui; Ma, Ning; Tuchina, Daria K.; Tuchin, Valery V.; Zhu, Dan

2016-08-01

Skin optical clearing can significantly enhance the ability of biomedical optical imaging. Some alcohols and sugars have been selected to be optical clearing agents (OCAs). In this work, we paid attention to the optical clearing potential of disaccharides. Sucrose and maltose were chosen as typical disaccharides to compare with fructose, an excellent monosaccharide-OCA, by using molecular dynamics simulation and an ex vivo experiment. The experimental results indicated that the optical clearing efficacy of skin increases linearly with the concentration for each OCA. Both the theoretical predication and experimental results revealed that the two disaccharides exerted a better optical clearing potential than fructose at the same concentration, and sucrose is optimal. Since maltose has an extremely low saturation concentration, the other two OCAs with saturation concentrations were treated topically on rat skin in vivo, and optical coherence tomography imaging was applied to monitor the optical clearing process. The results demonstrated that sucrose could cause a more significant increase in imaging depth and signal intensity than fructose.

Investigation of gaseous nuclear rocket technology

NASA Technical Reports Server (NTRS)

Kendall, J. S.

1972-01-01

The experimental and theoretical investigations conducted during the period from September 1969 through September 1972 are reported which were directed toward obtaining information necessary to determine the feasibility of the full-scale nuclear light bulb engine, and of small-scale nuclear tests involving fissioning uranium plasmas in a unit cell installed in a driver reactor, such as the Nuclear Furnace. Emphasis was placed on development of RF simulations of conditions expected in nuclear tests in the Nuclear Furnace. The work included investigations of the following: (1) the fluid mechanics and containment characteristics of one-component and two-component vortex flows, both unheated and RF-induction heated; (2) heating of particle-seeded streams by thermal radiation from a dc arc to simulate propellant heating; (3) condensation and separation phenomena for metal-vapor/heated-gas mixtures to provide information for conceptual designs of components of fuel exhaust and recycle systems; (4) the characteristics of the radiant energy spectrum emitted from the fuel region, with emphasis on definition of fuel and buffer-gas region seed systems to reduce the ultraviolet radiation emitted from the nuclear fuel; and (5) the effects of nuclear radiation on the optical transmission characteristics of transparent materials.

NuSTAR on-ground calibration: II. Effective area

NASA Astrophysics Data System (ADS)

Brejnholt, Nicolai F.; Christensen, Finn E.; Westergaard, Niels J.; Hailey, Charles J.; Koglin, Jason E.; Craig, William W.

2012-09-01

The Nuclear Spectroscopic Telescope ARray (NuSTAR) was launched in June 2012 carrying the first focusing hard X-ray (5-80keV) optics to orbit. The multilayer coating was carried out at the Technical University of Denmark (DTU Space). In this article we introduce the NuSTAR multilayer reference database and its implementation in the NuSTAR optic response model. The database and its implementation is validated using on-ground effective area calibration data and used to estimate in-orbit performance.

Raman-Induced Kerr Effect Studies.

DTIC Science & Technology

1980-06-10

appropriate parameters. He also has access to a ten joule Nd: glass laser a part of whose beam pumps a tunable dye laser. These lasers, according to theor...introduced. Quantum limited signal- proportional to the spontaneous Raman cross section. The to.noise ratios may be approached by the use of optical...ratio result from the use of optical ={B(W3 - w2) - 2A(t, - w2)1/24. (3) In (2) and (3), A(Aw) and BCAw) are the complex nuclear Manuscript received

Preparation and measurement of FBG-based length, temperature, and vibration sensors

NASA Astrophysics Data System (ADS)

Mikel, Bretislav; Helan, Radek; Buchta, Zdenek; Jelinek, Michal; Cip, Ondrej

2016-12-01

We present system of structure health measurement by optical fiber sensors based on fiber Bragg gratings. Our system is focused to additionally install to existing buildings. We prepared first set-up of the system to monitoring of the nuclear power plant containment shape deformation. The presented system can measure up to several tens of sensors simultaneously. Each sensor contains optical fiber grating to measurement of change of length and the other independed fiber grating to monitor the temperature and the other ineligible effects.

Nuclear-effects model embedded stochastically in simulation (NEMESIS) summary report. Technical paper

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

Youngren, M.A.

1989-11-01

An analytic probability model of tactical nuclear warfare in the theater is presented in this paper. The model addresses major problems associated with representing nuclear warfare in the theater. Current theater representations of a potential nuclear battlefield are developed in context of low-resolution, theater-level models or scenarios. These models or scenarios provide insufficient resolution in time and space for modeling a nuclear exchange. The model presented in this paper handles the spatial uncertainty in potentially targeted unit locations by proposing two-dimensional multivariate probability models for the actual and perceived locations of units subordinate to the major (division-level) units represented inmore » theater scenarios. The temporal uncertainty in the activities of interest represented in our theater-level Force Evaluation Model (FORCEM) is handled through probability models of the acquisition and movement of potential nuclear target units.« less

Two-Photon Autofluorescence Imaging Reveals Cellular Structures Throughout the Retina of the Living Primate Eye.

PubMed

Sharma, Robin; Williams, David R; Palczewska, Grazyna; Palczewski, Krzysztof; Hunter, Jennifer J

2016-02-01

Although extrinsic fluorophores can be introduced to label specific cell types in the retina, endogenous fluorophores, such as NAD(P)H, FAD, collagen, and others, are present in all retinal layers. These molecules are a potential source of optical contrast and can enable noninvasive visualization of all cellular layers. We used a two-photon fluorescence adaptive optics scanning light ophthalmoscope (TPF-AOSLO) to explore the native autofluorescence of various cell classes spanning several layers in the unlabeled retina of a living primate eye. Three macaques were imaged on separate occasions using a custom TPF-AOSLO. Two-photon fluorescence was evoked by pulsed light at 730 and 920 nm excitation wavelengths, while fluorescence emission was collected in the visible range from several retinal layers and different locations. Backscattered light was recorded simultaneously in confocal modality and images were postprocessed to remove eye motion. All retinal layers yielded two-photon signals and the heterogeneous distribution of fluorophores provided optical contrast. Several structural features were observed, such as autofluorescence from vessel walls, Müller cell processes in the nerve fibers, mosaics of cells in the ganglion cell and other nuclear layers of the inner retina, as well as photoreceptor and RPE layers in the outer retina. This in vivo survey of two-photon autofluorescence throughout the primate retina demonstrates a wider variety of structural detail in the living eye than is available through conventional imaging methods, and broadens the use of two-photon imaging of normal and diseased eyes.

Integrated optical dipole trap for cold neutral atoms with an optical waveguide coupler

NASA Astrophysics Data System (ADS)

Lee, J.; Park, D. H.; Mittal, S.; Dagenais, M.; Rolston, S. L.

2013-04-01

An integrated optical dipole trap uses two-color (red and blue-detuned) traveling evanescent wave fields for trapping cold neutral atoms. To achieve longitudinal confinement, we propose using an integrated optical waveguide coupler, which provides a potential gradient along the beam propagation direction sufficient to confine atoms. This integrated optical dipole trap can support an atomic ensemble with a large optical depth due to its small mode area. Its quasi-TE0 waveguide mode has an advantage over the HE11 mode of a nanofiber, with little inhomogeneous Zeeman broadening at the trapping region. The longitudinal confinement eliminates the need for a one dimensional optical lattice, reducing collisional blockaded atomic loading, potentially producing larger ensembles. The waveguide trap allows for scalability and integrability with nano-fabrication technology. We analyze the potential performance of such integrated atom traps.

Probing the nuclear susceptibility of mesoionic compounds using two-beam coupling with chirp-controlled pulses

NASA Astrophysics Data System (ADS)

Bosco, Carlos A. C.; Maciel, Glauco S.; Rakov, Nikifor; de Araújo, Cid B.; Acioli, Lúcio H.; Simas, Alfredo M.; Athayde-Filho, Petrônio F.; Miller, Joseph

2007-11-01

The third-order non-linear optical response of mesoionic compounds (MIC) in dimethylsulfoxide (DMSO) and methanol solutions was investigated by use of collinear pump and probe technique with chirp-controlled femtosecond pulses. The experiments allowed the investigation of non-instantaneous nuclear processes and thermal effects induced by two-photon absorption (TPA). We found that the nuclear non-linearity of MIC in DMSO is ˜1/5 the benzene, which was used as a reference material. This result is attributed to the large inertia of MIC to rotation, compared to benzene. The results for MIC in methanol indicate the influence of thermal effects due to TPA.

Direct measurement of nuclear cross sections of astrophysical relevance at LUNA: The 22Ne(p, γ) 23Na reaction

NASA Astrophysics Data System (ADS)

Ferraro, F.; LUNA Collaboration

2017-01-01

Most of the elements constituting the universe were produced in stars through a series of nuclear reactions. LUNA performs direct measurements of nuclear cross sections relevant to astrophysics, taking advantage of the low background at LNGS. The ^{22}Ne(p,γ)^{23}Na reaction rate, which belongs to the NeNa cycle of hydrogen burning, has been recently studied. Its rate is still very uncertain because of a lot of resonances lying inside the Gamow window. LUNA discovered three new resonances using two high-purity germanium detectors and considerably improved the existing upper limits on the lower energy resonances using a high-efficiency optically-segmented BGO crystal.

[A study on the relationship between postmortem interval and the changes of DNA content in the kidney cellule of rat].

PubMed

Liu, L; Peng, D B; Liu, Y; Deng, W N; Liu, Y L; Li, J J

2001-05-01

To study changes of DNA content in the kidney cellule of rats and relationship with the postmortem interval. This experiment chose seven parameter of cell nuclear, including the area and integral optical density, determined the changes of DNA content in the kidney cellule of 15 rats at different intervals between 0 and 48 h postmortem with auto-TV-image system. The degradation rate of DNA in nuclear has a certainty relationship to early PMI(in 48 h) of rat, and get binomial regress equation. Determining the quantity of DNA in nuclear should be an objective and exact way to estimate the PMI.

Small size yet big action: a simple sulfate anion templated a discrete 78-nuclearity silver sulfur nanocluster with a multishell structure.

PubMed

Cheng, Li-Ping; Wang, Zhi; Wu, Qiao-Yu; Su, Hai-Feng; Peng, Tao; Luo, Geng-Geng; Li, Yan-An; Sun, Di; Zheng, Lan-Sun

2018-03-07

A discrete 78-nucleus silver-sulfur nanocluster with a sulfate-centered multishell structure was isolated and characterized. Its crystal structure revealed 18 and 60 Ag atoms in the inner and outer shell, respectively. The inner shell of 18-nuclearity Ag atoms is a very rare convex polyhedron featuring an elongated triangular orthobicupola. The incorporation of a sulfate anion and multishell arrangement in the nanocluster led to a dramatic decrease in the band gap (E g = 1.40 eV). Our study showed that simple anions can also induce the formation of high-nuclearity silver clusters with excellent optical properties.

Using neutrons, X-rays and nuclear magnetism to determine the role of transition metal oxide inclusions on both glass structure and stability in automotive glass enamels.

PubMed

Bowron, Daniel T; Booth, Jonathan; Barrow, Nathan S; Sutton, Patricia; Johnson, Simon R

2018-05-23

Low levels of transition metal oxides in alkali borosilicate glass systems can drastically influence crystallisation and phase separation properties. We investigated the non-monotonic effect of manganese doping on suppressing crystallisation, and the influence on optical properties by iron oxide doping, in terms of local atomic structure. Structural models based on empirical potential structure refinement were generated from neutron and X-ray scattering data, and compared against multinuclear solid-state NMR. This revealed that a 2.5% manganese doping had a disruptive effect on the entire glass network, supressing crystallisation of an undesired bismuth silicate phase, and that iron species preferentially locate near borate tetrahedra. Preventing phase separation and controlling crystallisation behaviour of glass are critical to the ultimate properties of automotive glass enamels.

Swollen poly(dimethylsiloxane) (PDMS) as a template for inorganic morphologies.

PubMed

Brennan, Daniel P; Dobley, Arthur; Sideris, Paul J; Oliver, Scott R J

2005-12-06

We report a series of silica, titania, and zirconia microstructures synthesized within swollen poly(dimethylsiloxane) (PDMS). Voids created by solvent-swelling the polymer are used to template the product. The inorganic morphologies range from spheres to networks, depending upon the nature of the polymer, its degree of swelling, and the synthetic conditions. Organic solvents as well as pure metal alkoxide liquids have been used to swell the polymer. Once the alkoxide precursor is inside the swollen polymer, water is introduced to bring about hydrolysis and condensation polymerization. The product is a textured metal oxide within a PDMS matrix. Scanning electron microscopy (SEM), optical microscopy, nuclear magnetic resonance (NMR), and powder X-ray diffraction (PXRD) were used to characterize the products. Microstructures formed in this manner have potential use as an inexpensive route to catalysts, fillers, capsules, or membranes for separations.

Characterisation of large area THGEMs and experimental measurement of the Townsend coefficients for CF4

NASA Astrophysics Data System (ADS)

Burns, J.; Crane, T.; Ezeribe, A. C.; Grove, C. L.; Lynch, W.; Scarff, A.; Spooner, N. J. C.; Steer, C.

2017-10-01

Whilst the performance of small THGEMs is well known, here we consider the challenges in scaling these up to large area charge readouts. We first verify the expected gain of larger THGEMs by reporting experimental Townsend coefficients for a 10 cm diameter THGEM in low-pressure CF4. Large area 50 cm by 50 cm THGEMs were sourced from a commercial PCB supplier and geometrical imperfections were observed which we quantified using an optical camera setup. The large area THGEMs were experimentally characterised at Boulby Underground Laboratory through a series of gain calibrations and alpha spectrum measurements. ANSYS, Magboltz and Garfield++ simulations of the design of a TPC based on the large area THGEMs are presented. We also consider their implications for directional dark matter research and potential applications within nuclear security.

Beyond the Rayleigh instability limit for multicharged finite systems: From fission to Coulomb explosion

PubMed Central

Last, Isidore; Levy, Yaakov; Jortner, Joshua

2002-01-01

We address the stability of multicharged finite systems driven by Coulomb forces beyond the Rayleigh instability limit. Our exploration of the nuclear dynamics of heavily charged Morse clusters enabled us to vary the range of the pair potential and of the fissibility parameter, which results in distinct fragmentation patterns and in the angular distributions of the fragments. The Rayleigh instability limit separates between nearly binary (or tertiary) spatially unisotropic fission and spatially isotropic Coulomb explosion into a large number of small, ionic fragments. Implications are addressed for a broad spectrum of dynamics in chemical physics, radiation physics of ultracold gases, and biophysics, involving the fission of clusters and droplets, the realization of Coulomb explosion of molecular clusters, the isotropic expansion of optical molasses, and the Coulomb instability of “isolated” proteins. PMID:12093910

Mysteries of TOPSe revealed: insights into quantum dot nucleation.

PubMed

Evans, Christopher M; Evans, Meagan E; Krauss, Todd D

2010-08-18

We have investigated the reaction mechanism responsible for QD nucleation using optical absorption and nuclear magnetic resonance spectroscopies. For typical II-VI and IV-VI quantum dot (QD) syntheses, pure tertiary phosphine selenide sources (e.g., trioctylphosphine selenide (TOPSe)) were surprisingly found to be unreactive with metal carboxylates and incapable of yielding QDs. Rather, small quantities of secondary phosphines, which are impurities in tertiary phosphines, are entirely responsible for the nucleation of QDs; their low concentrations account for poor synthetic conversion yields. QD yields increase to nearly quantitative levels when replacing TOPSe with a stoiciometric amount of a secondary phosphine chalcogenide such as diphenylphosphine selenide. Based on our observations, we have proposed potential monomer identities, reaction pathways, and transition states and believe this mechanism to be universal to all II-VI and IV-VI QDs synthesized using phosphine based methods.

Mysteries of TOPSe Revealed: Insights into Quantum Dot Nucleation

PubMed Central

Evans, Christopher M.; Evans, Meagan E.

2010-01-01

We have investigated the reaction mechanism responsible for QD nucleation using optical absorption and nuclear magnetic resonance spectroscopies. For typical II-VI and IV-VI quantum dot (QD) syntheses, pure tertiary phosphine selenide sources (e.g. trioctylphosphine selenide (TOPSe)) were surprisingly found to be unreactive with metal carboxylates and incapable of yielding QDs. Rather, small quantities of secondary phosphines, which are impurities in tertiary phosphines, are entirely responsible for the nucleation of QDs; their low concentrations account for poor synthetic conversion yields. QD yields increase to nearly quantitative levels when replacing TOPSe with a stoiciometric amount of a secondary phosphine chalcogenide such as diphenylphosphine selenide. Based on our observations, we have proposed potential monomer identities, reaction pathways and transition states, and believe this mechanism to be universal to all II-VI and IV-VI QDs synthesized using phosphine based methods. PMID:20698646

Extraterrestrial applications of solar optics for interior illumination

NASA Technical Reports Server (NTRS)

Eijadi, David A.; Williams, Kyle D.

1992-01-01

Solar optics is a terrestrial technology that has potential extraterrestrial applications. Active solar optics (ASO) and passive solar optics (PSO) are two approaches to the transmission of sunlight to remote interior spaces. Active solar optics is most appropriate for task illumination, while PSO is most appropriate for general illumination. Research into solar optics, motivated by energy conservation, has produced lightweight and low-cost materials, products that have applications to NASA's Controlled Ecological Life Support System (CELSS) program and its lunar base studies. Specifically, prism light guides have great potential in these contexts. Several applications of solar optics to lunar base concepts are illustrated.

Pulsed laser versus electrical energy for peripheral nerve stimulation

PubMed Central

Wells, Jonathon; Konrad, Peter; Kao, Chris; Jansen, E. Duco; Mahadevan-Jansen, Anita

2010-01-01

Transient optical neural stimulation has previously been shown to elicit highly controlled, artifact-free potentials within the nervous system in a non-contact fashion without resulting in damage to tissue. This paper presents the physiologic validity of elicited nerve and muscle potentials from pulsed laser induced stimulation of the peripheral nerve in a comparative study with the standard method of electrically evoked potentials. Herein, the fundamental physical properties underlying the two techniques are contrasted. Key laser parameters for efficient optical stimulation of the peripheral nerve are detailed. Strength response curves are shown to be linear for each stimulation modality, although fewer axons can be recruited with optically evoked potentials. Results compare the relative transient energy requirements for stimulation using each technique and demonstrate that optical methods can selectively excite functional nerve stimulation. Adjacent stimulation and recording of compound nerve potentials in their entirety from optical and electrical stimulation are presented, with optical responses shown to be free of any stimulation artifact. Thus, use of a pulsed laser exhibits some advantages when compared to standard electrical means for excitation of muscle potentials in the peripheral nerve in the research domain and possibly for clinical diagnostics in the future. PMID:17537515

Novel optical waveguides by in-depth controlled electronic damage with swift ions

NASA Astrophysics Data System (ADS)

Olivares, J.; García-Navarro, A.; Méndez, A.; Agulló-López, F.; García, G.; García-Cabañes, A.; Carrascosa, M.

2007-04-01

We review recent results on a novel method to modify crystalline dielectric materials and fabricate optical waveguides and integrated optics devices. It relies on irradiation with medium-mass high-energy ions (2-50 MeV) where the electronic stopping power is dominant over that one associated to nuclear collisions. By exploiting the processing capabilities of the method, novel optical structures can be achieved at moderate (1014 cm-2) and even low and ultralow (1012 cm-2) fluences. In particular, step-like waveguides with a high index jump Δn ∼ 0.1-0.2, guiding both ordinary and extraordinary modes, have been prepared with F and O ions (20 MeV) at moderate fluences. They present good non-linear and electrooptic perfomance and low losses. (1 dB/cm). Moreover, useful optical waveguiding has been also achieved at ultralow frequencies (isolated track regime), using Cl and Si ions (40-45 MeV). In this latter case, the individual amorphous nanotracks, whose radius increases with depth, create an effective optical medium causing optical trapping.

A quasi-optical and corrugated waveguide microwave transmission system for simultaneous dynamic nuclear polarization NMR on two separate 14.1 T spectrometers

PubMed Central

Dubroca, Thierry; Smith, Adam N.; Pike, Kevin J.; Froud, Stuart; Wylde, Richard; Trociewitz, Bianca; McKay, Johannes; Mentink-Vigier, Frederic; van Tol, Johan; Wi, Sungsool; Brey, William; Long, Joanna R.; Frydman, Lucio; Hill, Stephen

2018-01-01

Nuclear magnetic resonance (NMR) is an intrinsically insensitive technique, with Boltzmann distributions of nuclear spin states on the order of parts per million in conventional magnetic fields. To overcome this limitation, dynamic nuclear polarization (DNP) can be used to gain up to three orders of magnitude in signal enhancement, which can decrease experimental time by up to six orders of magnitude. In DNP experiments, nuclear spin polarization is enhanced by transferring the relatively larger electron polarization to NMR active nuclei via microwave irradiation. Here, we describe the design and performance of a quasi-optical system enabling the use of a single 395 GHz gyrotron microwave source to simultaneously perform DNP experiments on two different 14.1 T (1H 600 MHz) NMR spectrometers: one configured for magic angle spinning (MAS) solid state NMR; the other configured for solution state NMR experiments. In particular, we describe how the high power microwave beam is split, transmitted, and manipulated between the two spectrometers. A 13C enhancement of 128 is achieved via the cross effect for alanine, using the nitroxide biradical AMUPol, under MAS-DNP conditions at 110 K, while a 31P enhancement of 160 is achieved via the Overhauser effect for triphenylphosphine using the monoradical BDPA under solution NMR conditions at room temperature. The latter result is the first demonstration of Overhauser DNP in the solution state at a field of 14.1 T (1H 600 MHz). Moreover these results have been produced with large sample volumes (~100 μL, i.e. 3 mm diameter NMR tubes). PMID:29459343

A quasi-optical and corrugated waveguide microwave transmission system for simultaneous dynamic nuclear polarization NMR on two separate 14.1 T spectrometers

NASA Astrophysics Data System (ADS)

Dubroca, Thierry; Smith, Adam N.; Pike, Kevin J.; Froud, Stuart; Wylde, Richard; Trociewitz, Bianca; McKay, Johannes; Mentink-Vigier, Frederic; van Tol, Johan; Wi, Sungsool; Brey, William; Long, Joanna R.; Frydman, Lucio; Hill, Stephen

2018-04-01

Nuclear magnetic resonance (NMR) is an intrinsically insensitive technique, with Boltzmann distributions of nuclear spin states on the order of parts per million in conventional magnetic fields. To overcome this limitation, dynamic nuclear polarization (DNP) can be used to gain up to three orders of magnitude in signal enhancement, which can decrease experimental time by up to six orders of magnitude. In DNP experiments, nuclear spin polarization is enhanced by transferring the relatively larger electron polarization to NMR active nuclei via microwave irradiation. Here, we describe the design and performance of a quasi-optical system enabling the use of a single 395 GHz gyrotron microwave source to simultaneously perform DNP experiments on two different 14.1 T (1H 600 MHz) NMR spectrometers: one configured for magic angle spinning (MAS) solid state NMR; the other configured for solution state NMR experiments. In particular, we describe how the high power microwave beam is split, transmitted, and manipulated between the two spectrometers. A 13C enhancement of 128 is achieved via the cross effect for alanine, using the nitroxide biradical AMUPol, under MAS-DNP conditions at 110 K, while a 31P enhancement of 160 is achieved via the Overhauser effect for triphenylphosphine using the monoradical BDPA under solution NMR conditions at room temperature. The latter result is the first demonstration of Overhauser DNP in the solution state at a field of 14.1 T (1H 600 MHz). Moreover these results have been produced with large sample volumes (∼100 μL, i.e. 3 mm diameter NMR tubes).

A quasi-optical and corrugated waveguide microwave transmission system for simultaneous dynamic nuclear polarization NMR on two separate 14.1 T spectrometers.

PubMed

Dubroca, Thierry; Smith, Adam N; Pike, Kevin J; Froud, Stuart; Wylde, Richard; Trociewitz, Bianca; McKay, Johannes; Mentink-Vigier, Frederic; van Tol, Johan; Wi, Sungsool; Brey, William; Long, Joanna R; Frydman, Lucio; Hill, Stephen

2018-04-01

Nuclear magnetic resonance (NMR) is an intrinsically insensitive technique, with Boltzmann distributions of nuclear spin states on the order of parts per million in conventional magnetic fields. To overcome this limitation, dynamic nuclear polarization (DNP) can be used to gain up to three orders of magnitude in signal enhancement, which can decrease experimental time by up to six orders of magnitude. In DNP experiments, nuclear spin polarization is enhanced by transferring the relatively larger electron polarization to NMR active nuclei via microwave irradiation. Here, we describe the design and performance of a quasi-optical system enabling the use of a single 395 GHz gyrotron microwave source to simultaneously perform DNP experiments on two different 14.1 T ( 1 H 600 MHz) NMR spectrometers: one configured for magic angle spinning (MAS) solid state NMR; the other configured for solution state NMR experiments. In particular, we describe how the high power microwave beam is split, transmitted, and manipulated between the two spectrometers. A 13 C enhancement of 128 is achieved via the cross effect for alanine, using the nitroxide biradical AMUPol, under MAS-DNP conditions at 110 K, while a 31 P enhancement of 160 is achieved via the Overhauser effect for triphenylphosphine using the monoradical BDPA under solution NMR conditions at room temperature. The latter result is the first demonstration of Overhauser DNP in the solution state at a field of 14.1 T ( 1 H 600 MHz). Moreover these results have been produced with large sample volumes (∼100 µL, i.e. 3 mm diameter NMR tubes). Copyright © 2018 Elsevier Inc. All rights reserved.

Local optical control of ferromagnetism and chemical potential in a topological insulator

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

Yeats, Andrew L.; Mintun, Peter J.; Pan, Yu

Many proposed experiments involving topological insulators (TIs) require spatial control over time-reversal symmetry and chemical potential. We demonstrate reconfigurable micron-scale optical control of both magnetization (which breaks time-reversal symmetry) and chemical potential in ferromagnetic thin films of Cr-(Bi,Sb) 2Te 3 grown on SrTiO 3. By optically modulating the coercivity of the films, we write and erase arbitrary patterns in their remanent magnetization, which we then image with Kerr microscopy. Additionally, by optically manipulating a space charge layer in the underlying SrTiO 3 substrates, we control the local chemical potential of the films. This optical gating effect allows us to writemore » and erase p-n junctions in the films, which we study with photocurrent microscopy. Both effects are persistent and may be patterned and imaged independently on a few-micron scale. As a result, dynamic optical control over both magnetization and chemical potential of a TI may be useful in efforts to understand and control the edge states predicted at magnetic domain walls in quantum anomalous Hall insulators.« less

Local optical control of ferromagnetism and chemical potential in a topological insulator

DOE PAGES

Yeats, Andrew L.; Mintun, Peter J.; Pan, Yu; ...

2017-09-12

Many proposed experiments involving topological insulators (TIs) require spatial control over time-reversal symmetry and chemical potential. We demonstrate reconfigurable micron-scale optical control of both magnetization (which breaks time-reversal symmetry) and chemical potential in ferromagnetic thin films of Cr-(Bi,Sb) 2Te 3 grown on SrTiO 3. By optically modulating the coercivity of the films, we write and erase arbitrary patterns in their remanent magnetization, which we then image with Kerr microscopy. Additionally, by optically manipulating a space charge layer in the underlying SrTiO 3 substrates, we control the local chemical potential of the films. This optical gating effect allows us to writemore » and erase p-n junctions in the films, which we study with photocurrent microscopy. Both effects are persistent and may be patterned and imaged independently on a few-micron scale. As a result, dynamic optical control over both magnetization and chemical potential of a TI may be useful in efforts to understand and control the edge states predicted at magnetic domain walls in quantum anomalous Hall insulators.« less

CURRENTLY AVAILABLE TECHNOLOGIES DEMONSTRATION FOR ALTERNATIVES TO RADIOLOGICAL SOURCES

EPA Science Inventory

EPA's Office of Radiation and Indoor Air awarded a contract to demonstrate that non-nuclear measurement using optical and magnetic technology can replace radioactive devices used to measure the thickness and density of various paper, film, and plastic sheets.

The Physics of Physical Examinations.

ERIC Educational Resources Information Center

Patterson, James D.

1989-01-01

Discussed are several topics on medical imaging including x-rays and Computer Assisted Tomography (CAT) scans, magnetic resonance imaging, fiber optics endoscopy, nuclear medicine and bone scans, positron-emission tomography, and ultrasound. The concepts of radiation dosage, electrocardiograms, and laser therapy are included. (YP)

Science Serves Society.

ERIC Educational Resources Information Center

Sneed, G. C.

This book discusses how some of the topics taught in a conventional physics course have been used to solve interesting technical problems in industry, medicine, agriculture, transportation, and other areas of society. The topics include heat, optics, magnetism and electricity, nuclear physics, and sound. (MLH)

Experimental results on the ω- and η'-nucleus potential - on the way to mesic states

NASA Astrophysics Data System (ADS)

Nanova, Mariana

2015-06-01

Different experimental approaches to determine the meson-nucleus optical potential are discussed. The experiments have been performed with the Crystal Barrel/TAPS detector system at the ELSA accelerator in Bonn and the Crystal Ball/TAPS at the MAMI accelerator in Mainz. Experimental results about the real and imaginary part of the η'- and ω-nucleus optical potential are presented. The imaginary part of the meson-nucleus optical potential is determined from the in-medium width of the meson by the measurement of the transparency ratio. Information on the real part of the optical potential is deduced from measurements of the excitation function and momentum distribution which are sensitive to the sign and depth of the potential. The results are discussed and compared to theoretical predictions. The data for both mesons are consistent with a weakly attractive potential. The formation and population of ω-nucleus and η'-nucleus bound states is additionally discussed.

Universal functions of nuclear proximity potential for Skyrme nucleus-nucleus interaction in a semiclassical approach

NASA Astrophysics Data System (ADS)

Gupta, Raj K.; Singh, Dalip; Kumar, Raj; Greiner, Walter

2009-07-01

The universal function of the nuclear proximity potential is obtained for the Skyrme nucleus-nucleus interaction in the semiclassical extended Thomas-Fermi (ETF) approach. This is obtained as a sum of the spin-orbit-density-independent and spin-orbit-density-dependent parts of the Hamiltonian density, since the two terms behave differently, the spin-orbit-density-independent part mainly attractive and the spin-orbit-density-dependent part mainly repulsive. The semiclassical expansions of kinetic energy density and spin-orbit density are allowed up to second order, and the two-parameter Fermi density, with its parameters fitted to experiments, is used for the nuclear density. The universal functions or the resulting nuclear proximity potential reproduce the 'exact' Skyrme nucleus-nucleus interaction potential in the semiclassical approach, within less than ~1 MeV of difference, both at the maximum attraction and in the surface region. An application of the resulting interaction potential to fusion excitation functions shows clearly that the parameterized universal functions of nuclear proximity potential substitute completely the 'exact' potential in the Skyrme energy density formalism based on the semiclassical ETF method, including also the modifications of interaction barriers at sub-barrier energies in terms of modifying the constants of the universal functions.

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

Alfaro, R.; Sandoval, A.; Cruz, E.

We have performed radiation tolerance tests on the BCF-99-29MC wavelength shifting fibers and the BC404 plastic scintillator from Bicron as well as on silicon rubber optical couplers. We used the 60Co gamma source at the Instituto de Ciencias Nucleares facility to irradiate 30-cm fiber samples with doses from 50 Krad to 1 Mrad. We also irradiated a 10x10 cm2 scintillator detector with the WLS fibers embedded on it with a 200 krad dose and the optical conectors between the scintillator and the PMT with doses from 100 to 300 krad. We measured the radiation damage on the materials by comparingmore » the pre- and post-irradiation optical transparency as a function of time.« less

Faithful Solid State Optical Memory with Dynamically Decoupled Spin Wave Storage

NASA Astrophysics Data System (ADS)

Lovrić, Marko; Suter, Dieter; Ferrier, Alban; Goldner, Philippe

2013-07-01

We report a high fidelity optical memory in which dynamical decoupling is used to extend the storage time. This is demonstrated in a rare-earth doped crystal in which optical coherences were transferred to nuclear spin coherences and then protected against environmental noise by dynamical decoupling, leading to storage times of up to 4.2 ms. An interference experiment shows that relative phases of input pulses are preserved through the whole storage and retrieval process with a visibility ≈1, demonstrating the usefulness of dynamical decoupling for extending the storage time of quantum memories. We also show that dynamical decoupling sequences insensitive to initial spin coherence increase retrieval efficiency.

Glycerol dehydration of native and diabetic animal tissues studied by THz-TDS and NMR methods

PubMed Central

Smolyanskaya, O. A.; Schelkanova, I. J.; Kulya, M. S.; Odlyanitskiy, E. L.; Goryachev, I. S.; Tcypkin, A. N.; Grachev, Ya. V.; Toropova, Ya. G.; Tuchin, V. V.

2018-01-01

The optical clearing method has been widely used for different spectral ranges where it provides tissue transparency. In this work, we observed the enhanced penetration of the terahertz waves inside biological samples (skin, kidney, and cornea) treated with glycerol solutions inducing changes of optical and dielectric properties. It was supported by the observed trend of free-to-bound water ratio measured by the nuclear magnetic resonance (NMR) method. The terahertz clearing efficiency was found to be less for diabetic samples than for normal ones. Results of the numerical simulation proved that pulse deformation is due to bigger penetration depth caused by the reduction of absorption and refraction at optical clearing. PMID:29541513

Faithful solid state optical memory with dynamically decoupled spin wave storage.

PubMed

Lovrić, Marko; Suter, Dieter; Ferrier, Alban; Goldner, Philippe

2013-07-12

We report a high fidelity optical memory in which dynamical decoupling is used to extend the storage time. This is demonstrated in a rare-earth doped crystal in which optical coherences were transferred to nuclear spin coherences and then protected against environmental noise by dynamical decoupling, leading to storage times of up to 4.2 ms. An interference experiment shows that relative phases of input pulses are preserved through the whole storage and retrieval process with a visibility ≈1, demonstrating the usefulness of dynamical decoupling for extending the storage time of quantum memories. We also show that dynamical decoupling sequences insensitive to initial spin coherence increase retrieval efficiency.

Targeting Nuclear Receptors with Marine Natural Products

PubMed Central

Yang, Chunyan; Li, Qianrong; Li, Yong

2014-01-01

Nuclear receptors (NRs) are important pharmaceutical targets because they are key regulators of many metabolic and inflammatory diseases, including diabetes, dyslipidemia, cirrhosis, and fibrosis. As ligands play a pivotal role in modulating nuclear receptor activity, the discovery of novel ligands for nuclear receptors represents an interesting and promising therapeutic approach. The search for novel NR agonists and antagonists with enhanced selectivities prompted the exploration of the extraordinary chemical diversity associated with natural products. Recent studies involving nuclear receptors have disclosed a number of natural products as nuclear receptor ligands, serving to re-emphasize the translational possibilities of natural products in drug discovery. In this review, the natural ligands of nuclear receptors will be described with an emphasis on their mechanisms of action and their therapeutic potentials, as well as on strategies to determine potential marine natural products as nuclear receptor modulators. PMID:24473166

Chernobyl Nuclear Catastrophe and the High Risk Potential for Mental Retardation.

ERIC Educational Resources Information Center

Holowinsky, Ivan Z.

1993-01-01

This report considers potential effects of the 1986 nuclear explosion at the Chernobyl (Ukraine) nuclear reactor. Approximately 17 million people, of whom 2.5 million were below the age of 5, are thought to have suffered some radioactive contamination. Many of these children are at high risk for mental retardation and learning disorders.…

Localization microscopy of DNA in situ using Vybrant(®) DyeCycle™ Violet fluorescent probe: A new approach to study nuclear nanostructure at single molecule resolution.

PubMed

Żurek-Biesiada, Dominika; Szczurek, Aleksander T; Prakash, Kirti; Mohana, Giriram K; Lee, Hyun-Keun; Roignant, Jean-Yves; Birk, Udo J; Dobrucki, Jurek W; Cremer, Christoph

2016-05-01

Higher order chromatin structure is not only required to compact and spatially arrange long chromatids within a nucleus, but have also important functional roles, including control of gene expression and DNA processing. However, studies of chromatin nanostructures cannot be performed using conventional widefield and confocal microscopy because of the limited optical resolution. Various methods of superresolution microscopy have been described to overcome this difficulty, like structured illumination and single molecule localization microscopy. We report here that the standard DNA dye Vybrant(®) DyeCycle™ Violet can be used to provide single molecule localization microscopy (SMLM) images of DNA in nuclei of fixed mammalian cells. This SMLM method enabled optical isolation and localization of large numbers of DNA-bound molecules, usually in excess of 10(6) signals in one cell nucleus. The technique yielded high-quality images of nuclear DNA density, revealing subdiffraction chromatin structures of the size in the order of 100nm; the interchromatin compartment was visualized at unprecedented optical resolution. The approach offers several advantages over previously described high resolution DNA imaging methods, including high specificity, an ability to record images using a single wavelength excitation, and a higher density of single molecule signals than reported in previous SMLM studies. The method is compatible with DNA/multicolor SMLM imaging which employs simple staining methods suited also for conventional optical microscopy. Copyright © 2016. Published by Elsevier Inc.

Extended optical model for fission

DOE PAGES

Sin, M.; Capote, R.; Herman, M. W.; ...

2016-03-07

A comprehensive formalism to calculate fission cross sections based on the extension of the optical model for fission is presented. It can be used for description of nuclear reactions on actinides featuring multi-humped fission barriers with partial absorption in the wells and direct transmission through discrete and continuum fission channels. The formalism describes the gross fluctuations observed in the fission probability due to vibrational resonances, and can be easily implemented in existing statistical reaction model codes. The extended optical model for fission is applied for neutron induced fission cross-section calculations on 234,235,238U and 239Pu targets. A triple-humped fission barrier ismore » used for 234,235U(n,f), while a double-humped fission barrier is used for 238U(n,f) and 239Pu(n,f) reactions as predicted by theoretical barrier calculations. The impact of partial damping of class-II/III states, and of direct transmission through discrete and continuum fission channels, is shown to be critical for a proper description of the measured fission cross sections for 234,235,238U(n,f) reactions. The 239Pu(n,f) reaction can be calculated in the complete damping approximation. Calculated cross sections for 235,238U(n,f) and 239Pu(n,f) reactions agree within 3% with the corresponding cross sections derived within the Neutron Standards least-squares fit of available experimental data. Lastly, the extended optical model for fission can be used for both theoretical fission studies and nuclear data evaluation.« less

Spectroelectrochemistry as a Strategy for Improving Selectivity of Sensors for Security and Defense Applications

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

Heineman, William R.; Seliskar, Carl J.; Morris, Laura K.

2012-12-19

Spectroelectrochemistry provides improved selectivity for sensors by electrochemically modulating the optical signal associated with the analyte. The sensor consists of an optically transparent electrode (OTE) coated with a film that preconcentrates the target analyte. The OTE functions as an optical waveguide for attenuated total reflectance (ATR) spectroscopy, which detects the analyte by absorption. Alternatively, the OTE can serve as the excitation light for fluorescence detection, which is generally more sensitive than absorption. The analyte partitions into the film, undergoes an electrochemical redox reaction at the OTE surface, and absorbs or emits light in its oxidized or reduced state. The changemore » in the optical response associated with electrochemical oxidation or reduction at the OTE is used to quantify the analyte. Absorption sensors for metal ion complexes such as [Fe(CN)6]4- and [Ru(bpy)3]2+ and fluorescence sensors for [Ru(bpy)3]2+ and the polycyclic aromatic hydrocarbon 1-hydroxypyrene have been developed. The sensor concept has been extended to binding assays for a protein using avidin–biotin and 17β-estradiol–anti-estradiol antibodies. The sensor has been demonstrated to measure metal complexes in complex samples such as nuclear waste and natural water. This sensor has qualities needed for security and defense applications that require a high level of selectivity and good detection limits for target analytes in complex samples. Quickly monitoring and designating intent of a nuclear program by measuring the Ru/Tc fission product ratio is such an application.« less

The Importance of Slag Structure to Boron Removal from Silicon during the Refining Process: Insights from Raman and Nuclear Magnetic Resonance Spectroscopy Study

NASA Astrophysics Data System (ADS)

Qian, Guoyu; Wang, Zhi; Gong, Xuzhong; Sun, Liyuan

2017-12-01

Slag structure plays an important role in determining the relative ease of boron removal from silicon. Correlation between slag structure and boron removal thermodynamics was experimentally studied by Raman and nuclear magnetic resonance (NMR) spectroscopy using CaO-SiO2-Na2O slags with different optical basicities (0.6 to 0.71). Optimization of slag depolymerization leads to efficient removal of boron. The extent of nonbridged oxygen content (NBO/T) and boron removal gradually increased with an increase in optical basicity from 0.6 to 0.66: B2O3 derived from boron oxidation captured nonbridging oxygens of Q 0(Si), Q 1(Si), and Q 2(Si), and was incorporated into the silicate network in the form of Q 3(Si and B). When optical basicity increased to 0.71, NBO/T rapidly increased and boron removal decreased considerably. Quick depolymerization of Q 3(Si and B) deteriorated the stability of boron. Various structural forms of boron in the silicate network were successfully detected: the BO3 trihedrons [3]B-3Si, [3]B-2Si-1NBO, and BO3 (nonring), and the BO4 tetrahedrons BO4 (1B, 3Si) and BO4 (0B, 4Si). BO4 (1B, 3Si) was the main structure contributing to the increase of boron capacity; BO3 (nonring), detected under higher optical basicity conditions, may cause deterioration of boron removal by suppressing its oxidation.

Filming nuclear dynamics of iodine using x-ray diffraction at the LCLS

NASA Astrophysics Data System (ADS)

Ware, Matthew; Natan, Adi; Glownia, James; Cryan, James; Bucksbaum, Phil

2017-04-01

We will provide an overview of our analysis of the nuclear dynamics of iodine. At the LCLS, we pumped a gas cell of iodine with a weak 520nm, 50 fs pulse, and the nuclear dynamics are then probed with 9 keV, 40 fs x-rays with variable time delay. This allows us to simultaneously image nuclear wavepackets on the dissociating A state, on the bound B state, and even Raman wavepackets in the ground electronic state. We will explain at length how we isolate each of these signals using a Legendre decomposition of our x-ray data and the selection rules for each of the transitions. Likewise, we will discuss how we convert the x-ray diffraction patterns into real-space movies of the nuclear dynamics. Research supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Atomic, Molecular, and Optical Science Program. Use of LCLS supported under DOE Contract No. DE-AC02-76F00515.

Applications of a global nuclear-structure model to studies of the heaviest elements

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

Moeller, P.; Nix, J.R.

1993-10-01

We present some new results on heavy-element nuclear-structure properties calculated on the basis of the finite-range droplet model and folded-Yukawa single-particle potential. Specifically, we discuss calculations of nuclear ground-state masses and microscopic corrections, {alpha}-decay properties, {beta}-decay properties, fission potential-energy surfaces, and spontaneous-fission half-lives. These results, obtained in a global nuclear-structure approach, are particularly reliable for describing the stability properties of the heaviest elements.

Integrated Optical Dipole Trap for Cold Neutral Atoms with an Optical Waveguide Coupler

NASA Astrophysics Data System (ADS)

Lee, J.; Park, D. H.; Mittal, S.; Meng, Y.; Dagenais, M.; Rolston, S. L.

2013-05-01

Using an optical waveguide, an integrated optical dipole trap uses two-color (red and blue-detuned) traveling evanescent wave fields for trapping cold neutral atoms. To achieve longitudinal confinement, we propose using an integrated optical waveguide coupler, which provides a potential gradient along the beam propagation direction sufficient to confine atoms. This integrated optical dipole trap can support an atomic ensemble with a large optical depth due to its small mode area. Its quasi-TE0 waveguide mode has an advantage over the HE11 mode of a nanofiber, with little inhomogeneous Zeeman broadening at the trapping region. The longitudinal confinement eliminates the need for a 1D optical lattice, reducing collisional blockaded atomic loading, potentially producing larger ensembles. The waveguide trap allows for scalability and integrability with nano-fabrication technology. We analyze the potential performance of such integrated atom traps and present current research progress towards a fiber-coupled silicon nitride optical waveguide integrable with atom chips. Work is supported by the ARO Atomtronics MURI. Work is supported by the ARO Atomtronics MURI.

Differential two-body compound nuclear cross section, including the width-fluctuation corrections

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

Brown, D.; Herman, M.

2014-09-02

We figure out the compound angular differential cross sections, following mainly Fröbrich and Lipperheide, but with the angular momentum couplings that make sense for optical model work. We include the width-fluctuation correction along with calculations.

QUARTERLY PROGRESS REPORT NO. 83,

DTIC Science & Technology

Topics included are: microwave spectroscopy; radio astronomy; solid-state microwave electronics; optical and infrared spectroscopy; physical electronics and surface physics; physical acoustics; plasma physics; gaseous electronics; plasmas and controlled nuclear fusion ; energy conversion research; statistical communication theory; linguistics; cognitive information processing; communications biophysics; neurophysiology; computation research.

Optical bistability for optical signal processing and computing

NASA Astrophysics Data System (ADS)

Peyghambarian, N.; Gibbs, H. M.

1985-02-01

Optical bistability (OB) is a phenomenon in which a nonlinear medium responds to an optical input beam by changing its transmission abruptly from one value to another. A 'nonlinear medium' is a medium in which the index of refraction depends on the incident light intensity. A device is said to be optically bistable if two stable output states exist for the same value of the input. Optically bistable devices can perform a number of logic functions related to optical memory, optical transistor, optical discriminator, optical limiter, optical oscillator, and optical gate. They also have the potential for subpicosecond switching, greatly exceeding the capability of electronics. This potential is one of several advantages of optical data processing over electronic processing. Other advantages are greater immunity to electromagnetic interference and crosstalk, and highly parallel processing capability. The present investigation is mainly concerned with all-optical etalon devices. The considered materials, include GaAs, ZnS and ZnSe, CuCl, InSb, InAs, and CdS.

Effects of nuclear transfer procedures on ES cell cloning efficiency in the mouse.

PubMed

Yabuuchi, Akiko; Yasuda, Yoshiko; Kato, Yoko; Tsunoda, Yukio

2004-04-01

Enucleated oocytes receiving mouse embryonic stem (ES) cells develop into fertile young. The developmental potential to young is low, however, and the rate of postnatal death is high. We examined the effect of various nuclear transfer procedures on the in vitro and in vivo developmental potential of nuclear-transferred oocytes. The potential of oocytes receiving ES cells at M phase to develop into blastocysts after fusion by Sendai virus was high compared with that after direct injection (67% vs. 30%). The developmental potential of oocytes receiving ES cells at the M phase is higher than that of oocytes receiving ES cells at the G(1) phase (30-67% vs. 2-5%). Developmental ability to live young was low in all groups (0-4%). Different activation protocols affected the potential to develop into blastocysts to a different extent (27-62%), but did not affect the potential to develop into live young (0-3%). The present study demonstrated that the various conditions examined did not affect the potential of nuclear-transferred oocytes receiving ES cells to develop into live young or the incidence of postnatal death.

Active Proton Interrogation for Homeland Security

NASA Astrophysics Data System (ADS)

Greene, Steven; Morris, Christopher; Canavan, Gregory; Chung, Kiwhan; Elson, Jay; Hogan, Gary; Makela, Mark; Mariam, Fesseha; Murray, Matthew; Saunders, Alexander; Spaulding, Randy; Wang, Zhehui; Waters, Laurie; Wysocki, Frederick

2010-02-01

Energetic proton beams may provide an attractive technology for active interrogation of nuclear threats because: they have large fission cross sections, long mean free paths and high penetration, and proton beams can be manipulated with magnetic optics. We have measured time-dependent cross sections for delayed neutrons and gamma rays using 800 MeV protons from the Los Alamos Neutron Science Center and 4 GeV protons from the Brookhaven Alternating Gradient Synchrotron for a set of bare and shielded targets. The results show significant signals from both unshielded and shielded nuclear materials. Results will be presented. )

Fiber optic sensors for nuclear power plant applications

NASA Astrophysics Data System (ADS)

Kasinathan, Murugesan; Sosamma, Samuel; BabuRao, Chelamchala; Murali, Nagarajan; Jayakumar, Tammana

2012-05-01

Studies have been carried out for application of Raman Distributed Temperature Sensor (RDTS) in Nuclear Power Plants (NPP). The high temperature monitoring in sodium circuits of Fast Breeder Reactor (FBR) is important. It is demonstrated that RDTS can be usefully employed in monitoring sodium circuits and in tracking the percolating sodium in the surrounding insulation in case of any leak. Aluminum Conductor Steel Reinforced (ACSR) cable is commonly used as overhead power transmission cable in power grid. The suitability of RDTS for detecting defects in ACSR overhead power cable, is also demonstrated.

Detection of intestinal dysplasia using angle-resolved low coherence interferometry

PubMed Central

Terry, Neil; Zhu, Yizheng; Thacker, Julie K. M.; Migaly, John; Guy, Cynthia; Mantyh, Christopher R.; Wax, Adam

2011-01-01

Angle-resolved low coherence interferometry (a/LCI) is an optical biopsy technique that allows for depth-resolved, label-free measurement of the average size and optical density of cell nuclei in epithelial tissue to assess the tissue health. a/LCI has previously been used clinically to identify the presence of dysplasia in Barrett's Esophagus patients undergoing routine surveillance. We present the results of a pilot, ex vivo study of tissues from 27 patients undergoing partial colonic resection surgery, conducted to evaluate the ability of a/LCI to identify dysplasia. Performance was determined by comparing the nuclear morphology measurements with pathological assessment of co-located physical biopsies. A statistically significant correlation between increased average nuclear size, reduced nuclear density, and the presence of dysplasia was noted at the basal layer of the epithelium, at a depth of 200 to 300 μm beneath the tissue surface. Using a decision line determined from a receiver operating characteristic, a/LCI was able to separate dysplastic from healthy tissues with a sensitivity of 92.9% (13/14), a specificity of 83.6% (56/67), and an overall accuracy of 85.2% (69/81). The study illustrates the extension of the a/LCI technique to the detection of intestinal dysplasia, and demonstrates the need for future in vivo studies. PMID:22029349

Detection of intestinal dysplasia using angle-resolved low coherence interferometry

NASA Astrophysics Data System (ADS)

Terry, Neil; Zhu, Yizheng; Thacker, Julie K. M.; Migaly, John; Guy, Cynthia; Mantyh, Christopher R.; Wax, Adam

2011-10-01

Angle-resolved low coherence interferometry (a/LCI) is an optical biopsy technique that allows for depth-resolved, label-free measurement of the average size and optical density of cell nuclei in epithelial tissue to assess the tissue health. a/LCI has previously been used clinically to identify the presence of dysplasia in Barrett's Esophagus patients undergoing routine surveillance. We present the results of a pilot, ex vivo study of tissues from 27 patients undergoing partial colonic resection surgery, conducted to evaluate the ability of a/LCI to identify dysplasia. Performance was determined by comparing the nuclear morphology measurements with pathological assessment of co-located physical biopsies. A statistically significant correlation between increased average nuclear size, reduced nuclear density, and the presence of dysplasia was noted at the basal layer of the epithelium, at a depth of 200 to 300 μm beneath the tissue surface. Using a decision line determined from a receiver operating characteristic, a/LCI was able to separate dysplastic from healthy tissues with a sensitivity of 92.9% (13/14), a specificity of 83.6% (56/67), and an overall accuracy of 85.2% (69/81). The study illustrates the extension of the a/LCI technique to the detection of intestinal dysplasia, and demonstrates the need for future in vivo studies.

PARACENTRAL ACUTE MIDDLE MACULOPATHY IN A PERIVENULAR FERN-LIKE DISTRIBUTION WITH EN FACE OPTICAL COHERENCE TOMOGRAPHY.

PubMed

Garrity, Sean T; Tseng, Victoria L; Sarraf, David

2017-11-22

To report a case of central retinal vein occlusion resulting in a perivenular pattern of paracentral acute middle maculopathy lesions best identified with en face optical coherence tomography (OCT). Retrospective case report. Optos ultra-widefield fluorescein angiography, spectral domain OCT, en face OCT, and OCT angiography were performed. A 41-year-old man presented with decreased vision in the right eye for 2 weeks. Funduscopic examination of the affected right eye was notable for subtle retinal whitening in the macula, mild retinal venous dilation and tortuosity, and few scattered retinal dot and blot hemorrhages consistent with an acute central retinal vein occlusion. Widefield fluorescein angiography demonstrated delayed arterial and venous filling but no evidence of significant peripheral retinal vascular ischemia. En face OCT segmented at the inner nuclear layer illustrated a remarkable and precise perivenular distribution of fern-like paracentral acute middle maculopathy with periarterial sparing, whereas en face OCT segmented at the outer nuclear layer demonstrated florid cystoid macular edema. At 6-week follow-up, OCT demonstrated patchy areas of atrophic inner nuclear layer and spontaneous resolution of the cystoid macular edema. Optical coherence tomography angiography at the level of the deep capillary plexus illustrated remarkable flow reduction of the deep capillary plexus in mainly a perivenular distribution. The authors report a case of a central retinal vein occlusion with mild retinal findings associated with a remarkable perivenular pattern of paracentral acute middle maculopathy with en face OCT. Follow-up OCT angiography demonstrated significant flow reduction of the deep capillary plexus in a perivenular pattern. The perivenular pattern of paracentral acute middle maculopathy lesions with en face OCT can be an important finding suggestive of a central retinal vein occlusion.

Acute progressive paravascular placoid neuroretinopathy with negative-type electroretinography in paraneoplastic retinopathy.

PubMed

Chen, Fred K; Chew, Avenell L; Zhang, Dan; Chen, Shang-Chih; Chelva, Enid; Chandrasekera, Erandi; Koay, Eleanor M H; Forrester, John; McLenachan, Samuel

2017-06-01

Paraneoplastic retinopathy can be the first manifestation of systemic malignancy. A subset of paraneoplastic retinopathy is characterized by negative-type electroretinography (ERG) without fundus abnormality. Here we describe the multimodal imaging and clinico-pathological correlation of a unique case of acute progressive paravascular placoid neuroretinopathy with suspected retinal depolarizing bipolar cell dysfunction preceding the diagnosis of metastatic small cell carcinoma of the prostate. ERG was performed according to the International Society for Clinical Electrophysiology of Vision standards. Imaging modalities included near-infrared reflectance, blue-light autofluorescence, fluorescein and indocyanine green angiographies, spectral domain optical coherence tomography, ultra-widefield colour and green-light autofluorescence imaging, microperimetry and adaptive optics imaging. Patient serum was screened for anti-retinal antibodies using western blotting. Immunostaining and histological analyses were performed on sections from human retinal tissues and a patient prostate biopsy. Serial multimodal retinal imaging, microperimetry and adaptive optics photography demonstrated a paravascular distribution of placoid lesions characterized by hyper-reflectivity within the outer nuclear layer resembling type 2 acute macular neuroretinopathy. There was no visible lesion within the inner nuclear layer despite electronegative-type ERG. Six months later, the patient presented with metastatic small cell carcinoma of the prostate. Tumour cells were immunopositive for glyceraldehyde-3-phosphate dehydrogenase, enolase and recoverin as well as neuroendocrine markers. The patient's serum reacted to cytoplasmic and nuclear antigens in the prostate biopsy and in human retina. Anti-retinal antibodies against several antigens were detected by both commercial and in-house western blots. A spectrum of autoreactive anti-retinal antibodies is associated with a unique phenotype of acute progressive paravascular placoid neuroretinopathy resulting in degeneration of photoreceptor cells, inner retinal dysfunction and classic electronegative ERG in paraneoplastic retinopathy. Detailed clinical, functional and immunological phenotyping of paraneoplastic retinopathy illustrated the complex mechanism of paraneoplastic syndrome.

Distributed optical fibre temperature measurements in a low dose rate radiation environment based on Rayleigh backscattering

NASA Astrophysics Data System (ADS)

Faustov, A.; Gussarov, A.; Wuilpart, M.; Fotiadi, A. A.; Liokumovich, L. B.; Kotov, O. I.; Zolotovskiy, I. O.; Tomashuk, A. L.; Deschoutheete, T.; Mégret, P.

2012-04-01

On-line monitoring of environmental conditions in nuclear facilities is becoming a more and more important problem. Standard electronic sensors are not the ideal solution due to radiation sensitivity and difficulties in installation of multiple sensors. In contrast, radiation-hard optical fibres can sustain very high radiation doses and also naturally offer multi-point or distributed monitoring of external perturbations. Multiple local electro-mechanical sensors can be replaced by just one measuring fibre. At present, there are over four hundred operational nuclear power plants (NPPs) in the world 1. Operating experience has shown that ineffective control of the ageing degradation of major NPP components can threaten plant safety and also plant life. Among those elements, cables are vital components of I&C systems in NPPs. To ensure their safe operation and predict remaining life, environmental monitoring is necessary. In particular, temperature and radiation dose are considered to be the two most important parameters. The aim of this paper is to assess experimentally the feasibility of optical fibre temperature measurements in a low doserate radiation environment, using a commercially available reflectometer based on Rayleigh backscattering. Four different fibres were installed in the Sub-Pile Room of the BR2 Material testing nuclear reactor in Mol, Belgium. This place is man-accessible during the reactor shut-down, allowing easy fibre installation. When the reactor operates, the dose-rates in the room are in a range 0.005-5 Gy/h with temperatures of 40-60 °C, depending on the location. Such a surrounding is not much different to some "hot" environments in NPPs, where I&C cables are located.

All optical experimental design for neuron excitation, inhibition, and action potential detection

NASA Astrophysics Data System (ADS)

Walsh, Alex J.; Tolstykh, Gleb; Martens, Stacey; Sedelnikova, Anna; Ibey, Bennett L.; Beier, Hope T.

2016-03-01

Recently, infrared light has been shown to both stimulate and inhibit excitatory cells. However, studies of infrared light for excitatory cell inhibition have been constrained by the use of invasive and cumbersome electrodes for cell excitation and action potential recording. Here, we present an all optical experimental design for neuronal excitation, inhibition, and action potential detection. Primary rat neurons were transfected with plasmids containing the light sensitive ion channel CheRiff. CheRiff has a peak excitation around 450 nm, allowing excitation of transfected neurons with pulsed blue light. Additionally, primary neurons were transfected with QuasAr2, a fast and sensitive fluorescent voltage indicator. QuasAr2 is excited with yellow or red light and therefore does not spectrally overlap CheRiff, enabling imaging and action potential activation, simultaneously. Using an optic fiber, neurons were exposed to blue light sequentially to generate controlled action potentials. A second optic fiber delivered a single pulse of 1869nm light to the neuron causing inhibition of the evoked action potentials (by the blue light). When used in concert, these optical techniques enable electrode free neuron excitation, inhibition, and action potential recording, allowing research into neuronal behaviors with high spatial fidelity.

Role of modified Becke-Johnson potential in computation of electronic and optical properties of mixed crystals CdxZn1-xSe

NASA Astrophysics Data System (ADS)

Talreja, Sonal; Ahuja, B. L.

2015-08-01

Electronic and optical properties of CdxZn1-xSe (x = 0, 0.25, 0.5, 0.75, 1) compounds are investigated using the first-principles full potential linearized augmented plane wave method. In particular, we have used modified version of the exchange potential of Becke and Johnson, so called mBJ potential. We have discussed the energy bands, density of states, and optical properties such as dielectric constants, refractive indices, reflection spectra, extinction coefficients of all the CdxZn1-xSe compounds. Our mBJ potential based data are found to be in excellent agreement with the available experimental data, which unambiguously validates the applicability of orbital independent exchange-correlation potential in mixed semiconductor crystals. The optical properties are discussed in terms of applicability of Cd-Zn-Se system in light-emitting diodes, UV detectors and filters, etc.

Optical properties of doped sol-gel silica glasses

NASA Astrophysics Data System (ADS)

King, Terence A.

1994-01-01

Sol-gel optical composites were developed and characterized for potential applications in optics, lasers, nonlinear optics, and optoelectronics. Post-doped xerogels were index matched by in-situ polymerization of monomers to form inorganic-organic composites of low scatter and high optical quality. Characterization of the microstructure was made by visible and IR absorption and Raman Spectroscopy and optical quality by attenuation and scatter measurement. Doping techniques were optimized using hypercritical drying and vacuum impregnation and doping distribution monitored by laser-induced fluorescence. One-tenth wavelength surfaces were formed by novel optical polishing. Organic molecular dopants were tested in laser and nonlinear systems. Initial third harmonic generation and Z-scan measurements have shown the potential for saturable absorption and optical limiting.