Theses and Dissertations

Issuing Body

Mississippi State University

Advisor

Dutta, Dipangkar

Committee Member

Crider, Benjamin P.

Committee Member

Winger, Jeff A.

Committee Member

Afanasjev, Anatoli V.

Committee Member

Chen, Jingdao

Other Advisors or Committee Members

Couture, Aaron J.

Date of Degree

8-8-2023

Document Type

Dissertation - Open Access

Major

Engineering Physics

Degree Name

Doctor of Philosophy (Ph.D)

College

James Worth Bagley College of Engineering

Department

Applied Physics Program

Abstract

The large thermal cross section of cadmium makes it ideal for many practical applications where screening of thermal neutrons is desired. For example, in non-destructive assay techniques, or for astrophysical studies of the s-process. All such applications require precise knowledge of the neutron-capture cross section on cadmium. Although there are some data on neutron-capture cross sections particularly at thermal energies and at energies relevant for astrophysics, there is very little data at most other energies. Further, the evaluated cross sections from the ENDF and JENDL databases disagree at high energies. Therefore, there is a critical need for precise knowledge of the 114Cd(n, gamma)115Cd cross section over a large range of incident neutron energies.

We performed a direct measurement of the neutron-capture cross section at the Los Alamos Neutron Science Center (LANSCE) using the Detector for Advanced Neutron Capture Experiments (DANCE). A highly enriched (∼$99%), 100 mg pressed metallic pellet sample of 114Cd was used to perform the neutron-capture measurements in the range of 1 eV to 300 keV using the white neutron source available at LANSCE. Additional neutron capture data were also taken on highly enriched samples of 112Cd and 113Cd to enable careful background subtraction of even the small contaminants found in the 114Cd sample. We used a large energy sum windows around the Q-value to circumvent any complication that may arise from populating the 180 keV isomeric (T1/2 = 44.56d) state in 115Cd.

Sponsorship

The neutron capture measurement was conducted at the facilities of the Los Alamos Neutron Science Center (LANSCE) at the Los Alamos National Lab (LANL), operated by Triad National Security, LLC, for the USDOE/NNSA under Contract No. 89233218CNA000001, and supported by the USDOE Office of Science under Award Number DE-SC0021175, and by USDOE-NP under contracts SC000056 and SC0021243. The “big g” measurements were done at the National Institute of Standards and Technology (NIST) and Mississippi State University and was funded by the National Science Foundation (NSF) through funding contract number 1707988.

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