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in creator/contributor: "McGrath, C. A."

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Actinide Targets for Neutron Cross Section Measurements (C)

The Advanced Fuel Cycle Initiative (AFCI) and the Generation IV Reactor Initiative have demonstrated a lack of detailed neutron cross-sections for certain "minor" actinides, those other than the most common (235U, 238U, and 239Pu). For some closed-fuel-cycle reactor designs more than 50% of reactivity will, at some point, be derived from “minor” actinides that currently have poorly known (n,g) and (n,f) cross sections. A program of measurements under AFCI has begun to correct this. One … more

Date: April 1, 2006

Creator: Baker, J. D. & McGrath, C. A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Partial (gamma)-Ray Cross Sections for the Reaction 239Pu(n,2n(gamma)i) and the 239Pu(n,2n) Cross Section

Absolute partial {gamma}-ray cross sections for production of discrete {gamma} rays in the {sup 239}Pu(n,2n{gamma}i){sup 238}Pu reaction have been measured. The experiments were performed at LANSCE/WNR on the 60R flight line. Reaction {gamma}-rays were measured using the large-scale Compton-suppressed array of Ge detectors, GEANIE. The motivation for this experiment, an overview of the partial {gamma}-ray cross-section measurement, and an introduction to the main experimental issues will be pre… more

Date: September 14, 2001

Creator: Beacker, J. A.; Bernstein, L. A.; Younes, W.; McNabb, D. P.; Garrett, P. E.; Archer, D. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Studying the Role of Nuclear Structure Effects in Neutron-Induced Reactions Using GEANIE at LANSCE

Efforts to model and measure absolute neutron-induced reaction cross sections have for the most part been limited by experimental techniques to neutron energies found in reactors and light-ion fusion reactions (i.e., t(d,n){alpha} etc.). This can in large part be attributed to the difficulty involved in making high-flux mono-energetic neutron beams with E{sub n} > 14 MeV. The result has been a lack of guidance for (n,xnypz{alpha}) reaction modeling for E{sub n} > 1-2 MeV. These limitation… more

Date: September 15, 2000

Creator: Bernstein, L. A.; Archer, D. E.; Becker, J. A.; Garrett, P. E.; Hauschild, K.; McGrath, C. A. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Measurement of Several 239Pu(n,xn) Partial (gamma)-Ray Cross Sections for x(<=)3 Using GEANIE at LANSCE/WNR

Previous experimental efforts to measure the {sup 239}Pu(n,2n) reaction cross section have relied on the detection of evaporated neutrons [Mat72,Fre85]. These efforts were hampered by the presence of the large ({sigma} {approx} 2 barns) neutron-induced fission channel which produces on average 3-4 neutrons [How71]. This paper is one of three manuscripts that document an effort to determine the {sup 239}Pu(n,2n) channel cross section using the GErmanium Array for Neutron Induced Excitations (GEA… more

Date: September 1, 2000

Creator: Bernstein, L. A.; Becker, J. A.; Garrett, P. E.; Hauschild, K.; McGrath, C. A.; McNabb, D. P. et al.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Nuclear Structure of the Closed Subshell Nucleus 90Zr Studied with the (n,n'(gamma)) Reaction

States in {sup 90}Zr have been observed with the (n,n{prime}{gamma}) reaction using both spallation and monoenergetic accelerator-produced neutrons. A scheme comprised of 81 levels and 157 transitions was constructed concentrating on levels below 5.6 MeV in excitation energy. Spins have been determined by considering data from all experimental studies performed for {sup 90}Zr. Lifetimes have been deduced using the Doppler-shift attenuation method for many of the states and transition rates have… more

Date: June 12, 2003

Creator: Garrett, P. E.; Younes, Y.; Becker, J. A.; Bernstein, L. A.; Baum, E. M.; DiPrete, D. P. et al.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Development of Neutron Probes for Characterization of Hazardous Materials in the Sub-surface Medium

Neutron probes are being developed at the Idaho National Engineering and Environmental Laboratory (INEEL) for the detection, identification and quantification of hazardous materials in the ground. Such materials include plutonium, uranium, americium, chlorine and fluorine. Both a Neutron Gamma (NG) probe and a Prompt Fission Neutron (PFN) probe are being developed. The NG probe is used primarily for nuclide identification and quantification measurements. The PFN is used mostly for the detection… more

Date: May 15, 2002

Creator: Keegan, R.P.; McGrath, C.A. & Lopez, J.C.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Xe-135 Production from Cf-252

135Xe is a good indicator that fission has occurred and is a valuable isotope that helps enforce the Comprehensive Test Ban Treaty. Due to its rather short half life and minimal commercial interest, there are no known sources where 135Xe can be purchased. Readily available standards of this isotope for calibrating collection and analytical techniques would be very useful. 135Xe can be produced in the fissioning of actinide isotopes, or by neutron capture on 134Xe. Since the neutron capture cros… more

Date: March 1, 2012

Creator: McGrath, C. A.; Houghton, T. P.; Pfeiffer, J. K. & Hague, R. K.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Neutron-Induced Partial Gamma-Ray Cross-Section Measurements with GEANIE at LANSCE/WNR

GEANIE is the first large-scale Ge detector array used in conjunction with a high-energy neutron spallation source. GEANIE consists of eleven Compton-suppressed planar detectors, nine suppressed and six unsuppressed co-axial detectors. Spallation neutrons are provided by the LANSCE/WNR facility, and reaction neutron energies are determined via time-of-flight. neutron flux is monitored in-beam with a fission chamber. GEANIE at LANSCE/WNR currently emphasizes the measurement of partial gamma-ray … more

Date: January 10, 2000

Creator: McNabb, D. P.; Becker, J. A.; Archer, D.; Bernstein, L. A.; Garrett, P. E.; McGrath, C. A. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Gamma-ray production cross sections from neutron interactions with iron.

The initial purpose of this experiment was to provide a consistent data base of neutron-induced gamma-ray production cross sections over a large energy range for use in estimating elemental composition of the martian surface by observing gamma rays produced by cosmic ray interactions on the planet's surface [Bo02]. However, these data should be useful for other projects such as oil-well logging, accelerator transmutation of nuclear waste, shielding calculations, gamma-ray heating for nuclear re… more

Date: January 1, 2002

Creator: Nelson, R. O. (Ronald O.); Laymon, C. M. (Charles M.); Wender, S. A. (Stephen A.); Drake, D. M. (Darrell M.); Drosg, Manfred; Bobias, S. G. (S. George) et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

DEVELOPMENT OF A NOVEL SOLVENT FOR THE SIMULTANEOUS SEPARATION OF STRONTIUM AND CESIUM FROM DISSOLVED SPENT NUCLEAR FUEL SOLUTIONS

The recovery of Cs and Sr from acidic solutions by solvent extraction has been investigated. The goal of this project was to develop an extraction process to remove Cs and Sr from high-level waste in an effort to reduce the heat loading in storage. Solvents for the extraction of Cs and Sr separately have been used on both caustic and acidic spent nuclear fuel waste in the past. The objective of this research was to find a suitable solvent for the extraction of both Cs and Sr simultaneously from… more

Date: October 3, 2004

Creator: Riddle, C. L.; Baker, J. D.; Law, J. D.; McGrath, C. A.; Meikrantz, D. H.; Mincher, B. J. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

The 235U(n,2n(gamma)) Yrast Partial Gamma-Ray Cross Sections: A Report on the 1998 -- 1999 GEANIE Data and Analysis Techniques Appendix

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Date: September 6, 2000

Creator: Younes, W.; Becker, J. A.; Bernstein, L A; Garrett, P. E.; McGrath, C. A.; McNabb, D. P. et al.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

The 235U(n,2n(gamma)) Yrast Partial Gamma-Ray Cross Sections: A Report on the 1998 -- 1999 GEANIE Data and Analysis Techniques

Measurements of partial {sup 235}U(n,2n{gamma}) {gamma}-ray cross sections have been carried out as a function of incident neutron energy using the GEANIE spectrometer at LANSCE/WNR. The yields of {gamma} rays resulting from the population of discrete levels in the residual nucleus {sup 234}U have been measured at incident neutron energies in the 1-20-MeV range. These data provide, with the aid of nuclear reaction modeling, a measurement of the {sup 235}U(n,2n) reaction cross section and serve … more

Date: September 1, 2000

Creator: Younes, W.; Becker, J. A.; Bernstein, L. A.; Garret, P. E.; McGrath, C. A.; McNabb, D. P. et al.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Transition from Asymmetric to Symmetric Fission in the 235U(n,f) Reaction

Prompt {gamma} rays from the neutron-induced fission of {sup 235}U have been studied using the GEANIE spectrometer situated at the LANSCE/WNR ''white'' neutron facility. Gamma-ray production cross sections for 29 ground-state-band transitions in 18 even-even fission fragments were obtained as a function of incident neutron energy, using the time-of-flight technique. Independent yields were deduced from these cross sections and fitted with standard formulations of the fragment charge and mass di… more

Date: July 19, 2001

Creator: Younes, W.; Becker, J. A.; Bernstein, L. A.; Garrett, P. E.; McGrath, C. A.; McNabb, D. P. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Nuclear Science at GEANIE

GEANIE at LANSCE/WNR combines the precision energy resolution of germanium detectors with the advantages of a white source providing neutrons with energies 1 < E{sub n}(MeV) < 250 to address a variety of topics in nuclear physics. The authors present the analysis of two data sets, n+{sup 235}U and n+{sup 92}Mo, acquired at GEANIE during the 1998 beam cycle. These data showcase the breadth of subjects under study at this facility, including the spectroscopy of stable and near-stable nuclei… more

Date: December 17, 1999

Creator: Younes, W.; Becker, J. A.; Bernstein, L. A.; Garrett, P. E.; McNabb, D. P.; McGrath, C. A. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Preliminary Report on the Population of the 235U T1/2=25-Minute Isomer by the (Nu,Nu'Gamma)Reaction

The population cross section of the T{sub 1/2} = 25-minute, E{sub x} = 76.8-keV isomer in {sup 235}U via the {sup 235}U(n,n{prime}{gamma}) reaction has been estimated in the E{sub n} = 2.1-20-MeV range. Gamma rays populating both isomer and ground states were detected using the GEANIE spectrometer at the LANSCE/WNR ''white-source'' neutron facility. Partial {gamma}-ray cross sections were obtained as a function of incident neutron energy, using {gamma}-ray spectroscopy and the time-of-flight te… more

Date: October 9, 2002

Creator: Younes, W.; Britt, H. C.; Becker, J. A.; Bernstein, L. A.; Garrett, P. E.; McGrath, C. A. et al.

Item Type: Report

Partner: UNT Libraries Government Documents Department