100 Matching Results

Search Results

Advanced search parameters have been applied.

Cross-Section at 15.6 and 16.1 MeV

Description: The intent of this investigation is the determination of the values of the Cs-133 (n,2n)Cs-132 cross-section at neutron energies of 15.6 and 16.1 MeV. Neutrons of this energy are produced with comparative ease by means of the D-T reaction, in which deuterons of energy 500 and 750 keV, respectively, are impingent upon a tritium target.
Date: May 1969
Creator: Pepper, George H.
Partner: UNT Libraries

Transportation risk assessment for the shipment of irradiated FFTF tritium target assemblies from the Hanford Site to the Savannah River Site

Description: A Draft Technical Information Document (HNF-1855) is being prepared to evaluate proposed interim tritium and medical isotope production at the Fast Flux Test Facility (FFTF). This report examines the potential health and safety impacts associated with transportation of irradiated tritium targets from FFTF to the Savannah River Site for processing at the Tritium Extraction Facility. Potential risks to workers and members of the public during normal transportation and accident conditions are assessed.
Date: November 19, 1997
Creator: Nielsen, D. L.
Partner: UNT Libraries Government Documents Department

New Monte Carlo simulations of the LLNL pulsed-sphere experiments

Description: From the late 1960s to about 1985, the Pulsed-Sphere Program at Lawrence Livermore National Laboratory (LLNL) was carried out to measure 14-MeV neutron leakage spectra from target spheres made out of various elements, compounds, and mixtures Data from these experiments have been and continue to be fundamental in the evaluation of neutron Monte Carlo transport codes and cross section data libraries In addition, the data provide important integral information for stockpile stewardship, fusion technology, neutron therapy, and other applications Therefore, comparisons between computer Monte Carlo simulations and the results of these experiments are pivotal for the integral testing of processed nuclear data libraries and transport codes Fortunately, a large subset of data from the pulsed-sphere program (some 70 experiments) is available as a computer file called disp93in Furthermore, in the past few years, there has been a remarkable improvement in computer performance that allows for more realistic simulations by Monte Carlo codes such as TART 4 Previous TART simulations of the pulsed-sphere experiments were performed using simplified models with relatively small numbers of histories and very large solid angle detectors to offset the limitations in computer power. Also, not all the TART input files were created with the same level of detail For example, some input files included the air around the sphere while others did not These factors prompted a study to simulate in more detail all of the available pulsed-sphere experiments using the Monte Carlo transport code, TART, and the LLNL evaluated neutron data library, ENDL The timing of this study is significant because many years have passed since those experiments were done, and only a few people who participated in them are still working at LLNL Their help has been essential for an accurate documentation of the experiments For the Stewardship Program it is important to preserve ...
Date: July 1, 1998
Creator: Marchetti, A.A., LLNL
Partner: UNT Libraries Government Documents Department

A-dependence of nuclear transparency in quasielastic A(e,e{prime}p) at high Q{sup 2}

Description: The A-dependence of the quasielastic A(e,e{prime}p) reaction has been studied with {sup 3}H, C, Fe, and Au nuclei at momentum transfers Q{sup 2} = 1, 3, 5, and 6.8(GeV/c){sup 2}. The authors extract the nuclear transparency T(A,Q{sup 2}), a measure of the average probability of escape of a proton from a nucleus A. Several calculations predict a significant increase in T with momentum transfer, a phenomenon known as color transparency. No statistically significant rise is seen for any of the nuclei studied.
Date: May 1, 1994
Creator: O`Neill, T.G.; Lorenzon, W. & Arrington, J.
Partner: UNT Libraries Government Documents Department

A study of CR-39 track response to charged particles from NOVA implosions

Description: We have exposed CR-39 track recording material to a number of NOVA implosions. Radiation from the implosion passed through an array of ranging filters, which aided identification of the incident particles and their energies. The etching procedure was calibrated by including a piece of track exposed to DD protons from a small accelerator. For the same shots, we quantitatively compare the DD neutron yield with the DD proton yield determined from the track. In DT implosions, tracks produced by neutron interactions prevent observation of charged-particle tracks that are produced by the processes of knock-on, secondary or tertiary fusion.
Date: June 14, 1996
Creator: Phillips, T.W.; Cable, M.D.; Hicks, D.G.; Li, C.K.; Petrasso, R.D. & Seguin, F.H.
Partner: UNT Libraries Government Documents Department

ICF burn-history measurments using 17-MeV fusion gamma rays

Description: Fusion reaction rate for inertial-confinement fusion (ICF) experiments at the Nova Laser Facility is measured with 30-ps resolution using a high-speed neutron detector. We are investigating a measurement technique based on the 16.7-MeV gamma rays that are released in deuterium-tritium fusion. Our concept is to convert gamma-ray energy into a fast burst of Cerenkov light that can be recorded with a high-speed optical detector. We have detected fusion gamma rays in preliminary experiments conducted at Nova where we used a tungsten/aerogel converter to generate Cerenkov light and an optical streak camera to record the signal.
Date: April 12, 1995
Creator: Lerche, R.A.; Cable, M.D. & Dendooven, P.G.
Partner: UNT Libraries Government Documents Department

Reducing deuterium-tritium ice roughness by electrical heating of the saturated vapor

Description: High gain targets for inertial confinement fusion (ICF) contain a layer of deuterium-tritium (DT) ice which surrounds a volume of DT gas in thermal equilibrium with the solid. The roughness of the cryogenic fuel layer inside of ICF targets is one of the sources of imperfections which cause implosions to deviate from perfect one dimensional performance. Experiments at Lawrence Livermore National Laboratory have shown that applying a heat flux across the inner surface of a hydrogen layer such as that inside an ICF target reduces the intrinsic roughness of the surface. We have developed a technique to generate this heat flux by applying and electric field to the DT vapor in the center of these shells. This vapor has a small but significant conductivity due to ionization caused by beta decay of tritium in the vapor and the solid. We describe here experiments using a 1.15 GHz cavity to apply an electric field to frozen DT inside of a sapphire test cell. The cell and cavity geometry allows visual observation of the frozen layers.
Date: June 14, 1996
Creator: Mapoles, E.R.; Sater, J.D.; Monsler, E. & Pipes, J.
Partner: UNT Libraries Government Documents Department

A search for the {Delta}{sup {minus}} wave-function component in light nuclei

Description: We have studied the ({pi}{sup +}, {pi}{sup {+-}}p) reactions on {sup 3}He, {sup 4}He, {sup 6}Li, and {sup 7}Li at incident energy 500 MeV in quasi-free kinematics. A signature attributable to pre-existing {Delta} components of the ground state wave function is observed.
Date: October 1, 1996
Creator: Morris, C.L.; Zumbro, J.D. & Boudrie, R.L.
Partner: UNT Libraries Government Documents Department

Monte Carlo approaches to the few-nucleon continuum

Description: Variational and Green's Function Monte Carlo methods are reviewed as applied to the study of the few-nucleon continuum at low- and intermediate- energies. Results recently obtained for the radiative and weak capture reactions n + {sup 3}He {yields} {sup 4}He + {gamma} and p + {sup 3}He {yields} {sup 4}He + e{sup +} + {nu}{sub e}, the {sup 5}He P-wave resonances, and the inclusive and exclusive electron scattering reactions on {sup 3}H and the helium isotopes are summarized.
Date: October 1, 1994
Creator: Schiavilla, R.; Carlson, J. & Wiringa, R.
Partner: UNT Libraries Government Documents Department

Electron scattering from polarized tritium

Description: the recent development of high-intensity gaseous targets of polarized hydrogen and deuterium raises the interesting possibility of developing a polarized tritium target that can operate in relatively high current electron beams. Here I discuss the feasibility of a measurement of the helicity-dependent asymmetry in {sup 3}{rvec H}({rvec e},e{prime}) inclusive quasielastic scattering with such a target.
Date: November 1, 1993
Creator: Jones, C. E.
Partner: UNT Libraries Government Documents Department

Producing {mu}{sup {minus}}d and {mu}{sup {minus}}t in vacuum

Description: After the feasibility of vacuum isolated {mu}{sup -}d production was demonstrated at TRIUMF in 1989, development was begun on a target system that would take advantage of the process to aid in the understanding of the muon catalyzed fusion cycle. Minimal neutron backgrounds, the ability to use silicon detectors, and compatibility with tritium were considered important for a very versatile target system. the advantages which the target gives isolating {mu}CF process will be outlined.
Date: December 31, 1992
Creator: Knowles, P. E.; Beer, G. A.; Mason, G. R.; Olin, A.; Bailey, J. M.; Beveridge, J. L. et al.
Partner: UNT Libraries Government Documents Department

Fusion cross sections and reactivities

Description: Cross section and reactivity data are summarized for several important fusion reactions. Reactivities are included for both Maxwellian plasmas and beam- Maxwellian target fusion. Equations, tabular and also graphical presentations are included for convenience in a variety of applications. (auth)
Date: June 17, 1974
Creator: Miley, G.H.; Towner, H. & Ivich, N.
Partner: UNT Libraries Government Documents Department

International cooperation at RTNS-II

Description: The Rotating Target Neutron Source-II (RTNS-II) facility at LLNL is a unique materials-test facility. It provides the most intense source of 14-MeV neutrons in the world. Dedicated operation in support of the fusion-materials-research community began in early 1979. Three years later, the Japanese Ministry of Education, Science, and Culture (Monbusho) and the US Department of Energy agreed to jointly support the RTNS-II operation and to share in the use of the facility.
Date: February 1, 1984
Creator: Logan, C.M.
Partner: UNT Libraries Government Documents Department

Development of Helios target insertion mechanism

Description: A system for precisely positioning a DT-filled target in the Helios target vacuum chamber is described. The target insertion mechanism (TIM), which is designed to insert either a target or a surrogate sphere into the vacuum chamber through an airlock to prevent loss of vacuum, is discussed in detail and its performance is evaluated.
Date: January 1, 1979
Creator: Day, R.D.; Cummings, C.E. & Tucker, H.E.
Partner: UNT Libraries Government Documents Department

RTNS-II: experience at 14-MeV source strengths between 1 x 10/sup 13/ and 4 x 10/sup 13/ n/s

Description: The design concepts, operational experience, and modifications of the two RTNS-II (Rotating Target Neutron Source-II) 14 MeV neutron sources are reviewed. The original design called for operation at a peak neutron source strength of 4 x 10/sup 13/ n/cm/sup 2/s. The facility was to operate at high plant factor and at an acceptable cost in both dose delivered to operating staff and releases to the environment. The possibilities of higher source strengths are discussed in light of the operating experience to date and of new technologies that may be applied to the problems of high flux generators of this type. Changes in ancillary equipment that would provide more efficient or safe operation are also indicated. (LEW)
Date: May 1, 1986
Creator: Davis, J.C.
Partner: UNT Libraries Government Documents Department

Recent implosion experiments at Nova

Description: Both electron (direct) and x-ray (indirect) driven implosions of DT targets have been done using approx.20 kJ of 0.35 ..mu..m light from the ten beam Nova laser facility. The direct drive targets (glass microballoons with nominal dimensions of 1000 ..mu..m x 2 ..mu..m and DT pressures of 12 to 14 atm) produced neutron yields in excess of 10/sup 13/ and fusion efficiencies >0.15%. Recent experiments will be described, with particular emphasis on measurements made using neutron diagnostics.
Date: June 1, 1986
Creator: Cable, M.D.; Lane, S.M.; Prussin, S.G.; Glendinning, S.G.; Munro, D.H.; Hatchett, S.P. et al.
Partner: UNT Libraries Government Documents Department

Stress calculations for RTNS-iI 50-cm targets. [Rotating target neutron source]

Description: Structural calculations made during design of a 50-cm target for the Rotating Target Neutron Source (RTNS-II) are detailed. The limited ability of the current 23-cm diameter target to dissipate the additional beam power required for a yield increase from 2 x 10/sup 13/ to 4 x 10/sup 13/ neutrons/second has resulted in the need for a larger target. The stresses of several design configurations for a 50-cm target were calculated. The stress contours that would occur in several different target designs with and without various types of structural reinforcement that reduce stress and deflection are presented.
Date: April 1, 1981
Creator: Schumacher, B.J. & House, P.A.
Partner: UNT Libraries Government Documents Department

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

Description: A recent investigation has shown that the /sup 3/H(d,n)/sup 4/He fusion reaction rate could be enhanced by a factor of 3/2 if the fusion plasma consisted of both polarized deuterons and tritons, forming exclusively the channel-spin S = 3/2, J = 3/2/sup +/ state. This result follows simply from the statistical weights of the quartet S = 3/2 and doublet S = 1/2 initial states, with the assumption of the single J = 3/2/sup +/ reaction amplitude. Since, with a small but nonzero J = 1/2/sup +/ amplitude, the maximum enhancement of the reaction occurs at the peak of the J = 3/2/sup +/ resonance, corresponding to a deuteron lab energy of 107 keV, it is of obvious interest to know what the enhancement would be at the lower energies that are typical of fusion plasmas. We are able to address this question by extending earlier calculations which gave the values of all of the spin-polarization observables at this J = 3/2/sup +/ resonance in both the /sup 3/H(d,n)/sup 4/He and the /sup 3/He(d,p)/sup 4/He reactions.
Date: June 1, 1985
Creator: Conzett, H.E. & Rioux, C.
Partner: UNT Libraries Government Documents Department

RTNS-II neutron sources: status report

Description: Experience with neutron sources consisting of air-insulated 400 kV deuteron accelerators and tritium targets which rotate at 5000 rpm is reported. These accelerators are part of the Rotating Target Neutron Source-II (RTNS-II) facility. A review of the accelerator design is given. Operation of the prototype accelerator using hydrogen beams is discussed in detail. The parameters are tabulated for the first accelerator operated as a neutron source in November, 1978. Additional terminal pumping has reduced the radiation level from bremsstrahlung by at least a factor of ten. Ion source performance with deuterium has not been as good as that obtained with hydrogen. Beam divergence at the acceleration column exit is also observed. Future efforts include the fabrication of large diameter targets and design changes to improve source operation.
Date: March 1, 1979
Creator: Davis, J.C.; Heikkinen, D.W.; Held, J.L.; Logan, C.M. & Osher, J.E.
Partner: UNT Libraries Government Documents Department

Target dynamics and thermonuclear burn, Part I

Description: The interaction between projectiles and targets in an impact fusion reactor system is considered. Heating by plane shock waves in DT is discussed. The condition for ignition is estimated and it is concluded that simple one-dimensional shock heating is unsuitable for fusion power production. It is suggested that shock heating followed by further compession would be an improvement.
Date: January 1, 1979
Creator: Marshall, J.
Partner: UNT Libraries Government Documents Department

Tritium pellet injector results

Description: Injection of solid tritium pellets is considered to be the most promising way of fueling fusion reactors. The Tritium Proof-of- Principle (TPOP) experiment has demonstrated the feasibility of forming and accelerating tritium pellets. This injector is based on the pneumatic pipe-gun concept, in which pellets are formed in situ in the barrel and accelerated with high-pressure gas. This injector is ideal for tritium service because there are no moving parts inside the gun and because no excess tritium is required in the pellet production process. Removal of /sup 3/He from tritium to prevent blocking of the cryopumping action by the noncondensible gas has been demonstrated with a cryogenic separator. Pellet velocities of 1280 m/s have been achieved for 4-mm-diam by 4-mm-long cylindrical tritium pellets with hydrogen propellant at 6.96 MPa (1000 psi). 10 refs., 10 figs.
Date: January 1, 1988
Creator: Fisher, P.W.; Bauer, M.L.; Baylor, L.R.; Deleanu, L.E.; Fehling, D.T.; Milora, S.L. et al.
Partner: UNT Libraries Government Documents Department

NP-MHTGR Fuel Development Program Results

Description: In August 1988, the Secretary of Energy announced a strategy to acquire New Production Reactor capacity for producing tritium. The strategy involved construction of a New Production Modular High Temperature Gas-Cooled Reactor (NP-MHTGR) where the Idaho National Engineering and Environmental Laboratory (INEEL) was selected as the Management and Operations contractor for the project. Immediately after the announcement in August 1988, tritium target particle development began with the INEEL selected as the lead laboratory. Fuel particle development was initially not considered to be on a critical path for the project, therefore, the fuel development program was to run concurrently with the design effort of the NP-MHTGR.
Date: October 1, 2002
Creator: Maki, John Thomas; Petti, David Andrew; Hobbins, Richard Redfield; McCardell, Richard K.; Shaber, Eric Lee & Southworth, Finis Hio
Partner: UNT Libraries Government Documents Department