A new 9Be(α,n) cross-section evaluation for use in the SOURCES computer code

Shores, Erik F.; Mueller, Gary Edward; Schlapper, Gerald A.

doi:10.1016/s0969-8043(03)00157-x

Cited by 6 publications

(2 citation statements)

References 16 publications

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“…The resulting Am-Be neutron energy spectrum agreed well with Marsh's spectrum [Marsh 1995] and showed marked improvement in the low-energy region below 1.5 MeV. The MC21 results and improvement in the predicted neutron energy spectrum are consistent with those of Shores et al [Shores 2003], where the SOURCES code is specifically modified, based on the findings of Geiger [Geiger 1976], to better account for the 9 Be breakup reaction cross sections. Neutrons emitted in the continuum (MT=91) uses the same Kalbach-Mann systematics neutron distribution data previously used for the total neutron emission MT=4 [Griesheimer 2017].…”

Section: Berylliumsupporting

confidence: 78%

(α,n) nuclear data scoping study

Smith

Brown

Romano

et al. 2020

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Neutrons from the (a,n) reaction are an important component of nondestructive assay techniques to determine enriched uranium and other actinide inventories in a variety of critical points in the nuclear fuel cycle. However, uncertainties in the cross section, total neutron yield and neutron spectrum, and gamma emissions from these reactions, such as 19 F(a,n) and 17,18 O(a,n), introduce large uncertainties in the determination of mass of actinides of interest and can represent several significant quantities in unaccounted material in certain facility processes. Calculations and measurements depend on accurate nuclear data; however, much of the relevant data in use today was measured in the 1980s and earlier and has not been updated. Thus, the current uncertainties in the cross sections and neutron emission spectra are unacceptably large. This report documents the results of a scoping study of (α,n) reaction data that considered the current state of the data and recommends areas of improvement. It also addresses the codes use to calculate the (a,n) neutron and gamma source terms and recommends code improvements to support required analysis.

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Section: Berylliumsupporting

confidence: 78%

(α,n) nuclear data scoping study

Smith

Brown

Romano

et al. 2020

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“…As SOURCES is designed to only model two-body nal states of the (α, n) reaction, the three-body neutron energy spectrum was approximated using an array of two-body nal state with incrementing Q-values. A similar approximation procedure was used in Shores, Mueller, and Schlapper (2003).…”

Section: Low Energy Neutron Simulationsmentioning

confidence: 99%

Dark Matter Limits From a 2L C3F8 Filled Bubble Chamber

Robinson¹

2015

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The PICO-2L C 3 F 8 bubble chamber search for Weakly Interacting Massive Particle (WIMP) dark matter was operated in the SNOLAB underground laboratory at the same location as the previous CF 3 I lled COUPP-4kg detector. Neutron calibrations using photoneutron sources in C 3 F 8 and CF 3 I lled calibration bubble chambers were performed to verify the sensitivity of these target uids to dark matter scattering. This data was combined with similar measurements using a low-energy neutron beam at the University of Montreal and in situ calibrations of the PICO-2L and COUPP-4kg detectors. C 3 F 8 provides much greater sensitivity to WIMP-proton scattering than CF 3 I in bubble chamber detectors. PICO-2L searched for dark matter recoils with energy thresholds below 10 keV. Radiopurity assays of detector materials were performed and the expected neutron recoil background was evaluated to be 1.6 +0.3 −0.9 single bubble events during the 211.5 kg-day exposure. Twelve single bubble dark matter candidate events were observed. These events were not uniformly distributed in time, and were likely caused by particulates in the active volume. Despite this background, PICO-2L sets a world-leading upper limit to the WIMP-proton spin dependent scattering cross-section.iv This thesis and its results rely on an immense amount of collaborative work and history. Many aspects of this thesis rely on research in nuclear physics, physical chemistry, and cosmology. Well written papers from Jack Gibbons, Dick Macklin, and Hal Schmitt at Oak Ridge National Laboratory and Walter John and John Prosser at Lawrence Livermore of dicult precision measurements of neutron producing reactions around 1960 were critical to most of the calibrations presented here. This and other dark matter research would not be possible without precision nuclear physics measurements, and data compilations such as ENDF/B, JENDL, and Mughabghab's Atlas of Neutron Resonances. Similarly, the work and products of the National Institute of Science and Technology were critical in understanding the physics of PICO bubble chambers and radiation within them. For the use of their equipment and expertise, and for sparking my interest in Nuclear Physics, I thank Ernst Rehm, Claudio Ugalde, and Brad DiGiovine at Argonne National Laboratory. Without their help, we would not have rapidly discovered the poor nucleation eciency of CF 3 I and PICO-2L would not have set world's best dark matter limits presented here. As`the COUPP graduate student', I am indebted to both my student predecessors Drew Fustin and Matthieu Zydagis for their herculean eorts to develop the superheated uid bubble chamber. These detectors could not have been constructed, run, understood without the`COUPP Post-doc Committee' of Jeter Hall, Eric Dahl, Hugh Lippincott, Russell Neilson, and Eric Vàsquez-Jauregui. For them and other long-time and recent members of the PICO collaboration, thank you. Many people have provided me with the opportunities that have brought me to where I am today. I will highlight Glenn Grant,...

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