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Development of a /sup 3/He/Xe gas scintillation counter to measure the /sup 3/He(n,p)T cross section in the intermediate energy range

Description: A /sup 3/He/Xe gas scintillation counter has been developed for measuring the neutron energy range from thermal to 3 MeV. Great effort was concentrated on improving the detector design to optimize light production and collection to improve the energy resolution which is primarily controlled by photon statistics. The detectors were tested using a /sup 238/Pu alpha-particle source, a thermal neutron beam from the NBS reactor, and the white-neutron spectrum from the NBS linac. The detector measure… more
Date: January 1, 1988
Creator: Behrens, J. W.; Wasson, O. A.; Carlson, A. D. & Ma, Hongchang
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Neutron cross section standards evaluations for ENDF/B-VI

Description: The neutron cross section standards are now being evaluated as the initial phase in the development of the new ENDF/B-VI file. These standards evaluations are following a somewhat different process compared with that used for earlier versions of ENDF. The primary effort is concentrated on a simultaneous evaluation using a generalized least squares program, R-matrix evaluations, and a procedure for combining the results of these evaluations. The ENDF/B-VI standards evaluation procedure is outlin… more
Date: 1985
Creator: Carlson, A. D.; Poenitz, W. P.; Hale, G. M. & Peelle, R. W.
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Partner: UNT Libraries Government Documents Department
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The data base of the standards and related cross sections after ENDF/B-VI

Description: A brief description is given of the procedure used in the global evaluation of the standards and other important cross sections for ENDF/B-VI. The standards involved were {sup 6}Li(n,t), {sup 10}B(n,{alpha}{sub 1}), {sup 197}Au(n,{gamma}), and {sup 235}U(n,f). Other standards evaluated independently were H(n,p), {sup 3}He(n,p), C(n,f). The other cross sections involved were {sup 238}U(n,{gamma}), {sup 238}U(n,f), and {sup 239}Pu(n,f). The results of the evaluation are compared with new or revis… more
Date: December 31, 1992
Creator: Poenitz, W.P. & Carlson, A.D.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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A study of the /sup 235/U(n,f) cross section in the 3 to 30 MeV energy region

Description: The /sup 235/U(n,f) cross section is often considered the most favorable of the neutron cross section standards. Above a few MeV, however, the uncertainties are still unacceptably high, except for the 14 MeV region. In an effort to improve the accuracy of this cross section, measurements have been initiated at the new target 4 facility at the Los Alamos National Laboratory (LANL) 800 MeV proton accelerator. This target provides an intense source of high energy neutrons at the 20 meter flight pa… more
Date: January 1, 1988
Creator: Carlson, A. D.; Wasson, O. A.; Lisowski, P. W.; Ullmann, J. L. & Hill, N. W.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Measurements of the {sup 235}U(n,f) cross section in the 3 to 30 MeV neutron energy region

Description: To improve the accuracy of the {sup 235}U(n,f) cross section, measurements have been made of this standard cross section at the target 4 facility at Los Alamos National Laboratory (LANL). The data were obtained at the 20-meter flight path of that facility. The fission reaction rate was determined with a fast parallel plate ionization chamber and the neutron fluence was measured with an annular proton recoil telescope. The measurements provide the shape of the {sup 235}U(n,f) cross section relat… more
Date: December 31, 1991
Creator: Carlson, A. D.; Wasson, O. A. & Lisowski, P. W.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Neutron induced fission cross section ratios for /sup 232/Th, /sup 235,238/U, /sup 237/Np, and /sup 239/Pu from 1 to 400 MeV

Description: Time-of-flight measurements of neutron induced fission cross section ratios for /sup 232/Th, /sup 235,238/U, /sup 237/Np, and /sup 239/Pu, were performed using the WNR high intensity spallation neutron source located at Los Alamos National Laboratory. A multiple-plate gas ionization chamber located at a 20-m flight path was used to simultaneously measure the fission rate for all samples over the energy range from 1 to 400 MeV. Because the measurements were made with nearly identical neutron flu… more
Date: 1988
Creator: Lisowski, P. W.; Ullmann, J. L.; Balestrini, S. J.; Carlson, A. D.; Wasson, O. A. & Hill, N. W.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

The data base of the standards and related cross sections after ENDF/B-VI

Description: A brief description is given of the procedure used in the global evaluation of the standards and other important cross sections for ENDF/B-VI. The results of the evaluation are compared with new or revised experimental data.
Date: January 1, 1992
Creator: Poenitz, W.P. (Argonne National Lab., IL (United States)) & Carlson, A.D. (National Inst. of Standards and Technology, Washington, DC (United States))
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Measurements of the /sup 235/U(n,f) standard cross section at the National Bureau of Standards

Description: The primary mission of the Neutron Interactions and Dosimetry Group at the National Bureau of Standards (NBS) is the measurement of the standard neutron cross sections. The group has had a long-term program for the measurement of one of the most important of these cross sections---the neutron-induced fission cross section of /sup 235/U. Since the ENDF/B-VI evaluation has been recently released, it is appropriate to review the measurements of the /sup 235/U(n,f) cross section which have been mad… more
Date: January 1, 1988
Creator: Johnson, R. G.; Carlson, A. D.; Wasson, O. A.; Duvall, K. C.; Behrens, J. W.; Meier, M. M. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Fission cross section ratios for sup 233,234,236 U relative to sup 235 U from 0. 5 to 400 MeV

Description: Neutron-induced fission cross section ratios from 0.5 to 400 MeV for samples of {sup 233, 234, 236}U relative to {sup 235}U have been measured at the WNR neutron Source at Los Alamos. The fission reaction rate was determined using a fast parallel plate ionization chamber at a 20-m flight path. Cross sections over most the energy range were also extracted using the neutron fluence determined with three different proton telescope arrangements. Those data provided the shape of the {sup 235}U(n,f) … more
Date: January 1, 1991
Creator: Lisowski, P. W.; Gavron, A.; Parker, W. E.; Balestrini, S. J.; Carlson, A. D.; Wasson, O. A. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Fission cross sections in the intermediate energy region

Description: Until recently there has been very little cross section data for neutron-induced fission in the intermediate energy region, primarily because no suitable neutron source has existed. At Los Alamos, the WNR target-4 facility provides a high-intensity source of neutrons nearly ideal for fission measurements extending from a fraction of a MeV to several hundred MeV. This paper summarizes the status of fission cross section data in the intermediate energy range (En > 30 MeV) and presents our fission… more
Date: January 1, 1991
Creator: Lisowski, P. W.; Gavron, A.; Parker, W. E.; Ullmann, J. L.; Balestrini, S. J.; Carlson, A. D. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Measurement of the angular distribution of neutron-proton scattering at 10 MeV

Description: The relative angular distribution of neutrons scattered from protons was measured at an incident neutron energy of 10 MeV at the Ohio University Accelerator Laboratory. An array of 11 detector telescopes at laboratory angles of 0 to 60 degrees was used to detect recoil protons from neutron interactions with a CH{sub 2} (polypropylene) target. Data for 7 of these telescopes were obtained with one set of electronics and are presented here. These data, from 108 to 180 degrees for the center-of-mas… more
Date: December 31, 1995
Creator: Haight, R. C.; Bateman, F. B.; Grimes, S. M.; Brient, C. E.; Massey, T. N.; Wasson, O. A. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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MEASUREMENTS OF THE H(N,N) ANGULAR DISTRIBUTION OF 10MEV NEUTRON ENERGY.

Description: Relative measurements of the cross section for scattering of neutrons by protons have been made at 10 MeV neutron energy for center-of-mass neutron scattering angles from 60' to 180'. The measurements were made using the Ohio University Accelerator Laboratory's tandem Van de Graaff accelerator with the D(d,n) reaction as the neutron source. The data are in good agreement with predictions from the phase shift analyses of Arndt, the groups of Nijmegen and Bonn, and the ENDF/B-V evaluation. The EN… more
Date: January 1, 2001
Creator: Boukharouba, N.; Bateman, F. B. (Fred B.); Brient, C. E.; Carlson, A. D.; Grimes, S. M.; Massey, T. N. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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ENDF/B-VII.0: Next Generation Evaluated Nuclear Data Library for Nuclear Science and Technology

Description: We describe the next generation general purpose Evaluated Nuclear Data File, ENDF/B-VII.0, of recommended nuclear data for advanced nuclear science and technology applications. The library, released by the U.S. Cross Section Evaluation Working Group (CSEWG) in December 2006, contains data primarily for reactions with incident neutrons, protons, and photons on almost 400 isotopes. The new evaluations are based on both experimental data and nuclear reaction theory predictions. The principal advan… more
Date: October 2, 2006
Creator: Chadwick, M. B.; Oblozinsky, P.; Herman, M.; Greene, N. M.; McKnight, R. D.; Smith, D. L. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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