The Los Alamos National Laboratory Spallation Neutron Sources

Lisowski, P.W.; Bowman, C.D.; Russell, Gary J.; Wender, S. A.

doi:10.13182/nse90-a27471

Cited by 348 publications

(159 citation statements)

References 5 publications

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“…Cross sections of neutron-induced reactions on 242m Am were measured at the LANSCE Lujan Neutron Scattering Center [44] with DANCE. The DANCE array consists of 160 equal-volume, equal-solid-angle BaF 2 crystals arranged in a 4π geometry.…”

Section: Methodsmentioning

confidence: 99%

Measurement of theAm242mneutron-induced reaction cross sections

Buckner

Henderson

et al. 2017

Phys. Rev. C

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The neutron-induced reaction cross sections of 242m Am were measured at the Los Alamos Neutron Science Center using the Detector for Advanced Neutron-Capture Experiments array along with a compact parallel-plate avalanche counter for fission-fragment detection. A new neutron-capture cross section was determined, and the absolute scale was set according to a concurrent measurement of the well-known 242m Am(n,f) cross section. The (n,γ) cross section was measured from thermal to an incident energy of 1 eV at which point the data quality was limited by the reaction yield in the laboratory. Our new 242m Am fission cross section was normalized to ENDF/B-VII.1 to set the absolute scale, and it agreed well with the (n,f) cross section reported by Browne et al. from thermal energy to 1 keV. The average absolute capture-to-fission ratio was determined from thermal to En = 0.1 eV, and it was found to be 26(4)% as opposed to the ratio of 19% from the ENDF/B-VII.1 evaluation.

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Section: Methodsmentioning

confidence: 99%

Measurement of theAm242mneutron-induced reaction cross sections

Buckner

Henderson

et al. 2017

Phys. Rev. C

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“…Over the past few years, we have obtained new Γ 0 n data [3,4] at the Oak Ridge Electron Linear Accelerator (ORELA) [5] and Los Alamos Neutron Science Center (LANSCE) [6] facilities that are much better than previous data. We discuss results of using these data to test the PTD in Section 3.…”

Section: Introductionmentioning

confidence: 99%

Neutron resonance data exclude random matrix theory

Koehler

Bečvář

Krtička

et al. 2012

Fortschritte der Physik

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Key words Porter-Thomas distribution, random matrix theory.Almost since the time it was formulated, the overwhelming consensus has been that random matrix theory (RMT) is in excellent agreement with neutron resonance data. However, over the past few years, we have obtained new neutron-width data at Oak Ridge and Los Alamos National Laboratories that are in stark disagreement with this theory. We also have reanalyzed neutron widths in the most famous data set, the nuclear data ensemble (NDE), and found that it is seriously flawed, and, when analyzed carefully, excludes RMT with high confidence. More recently, we carefully examined energy spacings for these same resonances in the NDE using the ∆3 statistic. We conclude that the data can be found to either confirm or refute the theory depending on which nuclides and whether known or suspected p-wave resonances are included in the analysis, in essence confirming results of our neutron-width analysis of the NDE. We also have examined radiation widths resulting from our Oak Ridge and Los Alamos measurements, and find that in some cases they do not agree with RMT. Although these disagreements presently are not understood, they could have broad impact on basic and applied nuclear physics, from nuclear astrophysics to nuclear criticality safety.

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“…Dickens et al [11] measured at ORELA in 1991 γ -rays for incident neutron energies between 0.8 and 41 MeV by using a HPGe detector at 125 degrees. In 2004, more accurate gamma-ray cross-sections was obtained by Nelson et al [12] with the Germanium Array for Neutron-Induced Excitations (GEANIE) at Weapons Neutron Research Facility (WNR) at LANSCE [13]. Spallation neutrons from the target travel a well-collimated 20.34-m flight path to the GEANIE sample.…”

Section: The Analysis Of Experiments Datamentioning

confidence: 99%

The evaluation of experimental data in fast range for n + ⁵⁶Fe(n,inl)

et al. 2017

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Abstract. Iron is one of the five materials selected for evaluation within the pilot international evaluation project CIELO. Analysis of experimental data for n+ 56 Fe reaction is the basis for constraining theoretical calculations and eventual creation of the evaluated file. The detail analysis was performed for inelastic cross sections of neutron induced reactions with 56 Fe in the fast range up to 20 MeV where there are significant differences among the main evaluated libraries, mainly caused by the different inelastic scattering cross section measurements. Gamma-ray production cross sections provide a way to gain experimental information about the inelastic cross section. Large discrepancies between experimental data for the 847-keV gamma ray produced in the 56 Fe(n,n 1 'γ ) reaction were analyzed. In addition, experimental data for elastic scattering cross section between 9.41∼11 MeV were used to deduce the inelastic cross section from the unitarity constrain.

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The Los Alamos National Laboratory Spallation Neutron Sources

Cited by 348 publications

References 5 publications

Measurement of theAm242mneutron-induced reaction cross sections

Measurement of theAm242mneutron-induced reaction cross sections

Neutron resonance data exclude random matrix theory

The evaluation of experimental data in fast range for n + ⁵⁶Fe(n,inl)

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The Los Alamos National Laboratory Spallation Neutron Sources

Cited by 348 publications

References 5 publications

Measurement of theAm242mneutron-induced reaction cross sections

Measurement of theAm242mneutron-induced reaction cross sections

Neutron resonance data exclude random matrix theory

The evaluation of experimental data in fast range for n + 56Fe(n,inl)

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The evaluation of experimental data in fast range for n + ⁵⁶Fe(n,inl)