Enhancement of sub-thermal neutron flux through cold polyethylene

Issue title: UCANS-web 2020

Guest editors: David Baxter, Thomas Gutberlet, Yoshie Otake, Frédéric Ott and Xuewu Wang

Article type: Research Article

Authors: Fritz, D.^{; *} | Danon, Y. | Liu, E.

Affiliations: Rensselaer Polytechnic Institute, Troy, NY 12180, United States. E-mails: fritzd3@rpi.edu, danony@rpi.edu, liue@rpi.edu

Correspondence: [*] Corresponding author. E-mail: fritzd3@rpi.edu.

Abstract: Total thermal neutron cross section measurements serve as the primary means of validation for thermal neutron scattering kernels, an important quantity for neutron transport calculations. In an effort to improve the quality of thermal neutron scattering kernels, researchers at Rensselaer Polytechnic Institute (RPI) designed and constructed a polyethylene based cold moderation system to enhance neutron flux below 10 meV when coupled with the Enhanced Thermal Target (ETT) at the RPI Gaerttner LINAC. The final design yielded an increase in sub-thermal neutron flux (below 10 meV) by a factor of 4.5 for a moderator temperature of 37.5 K relative to the ETT alone. A further increase to a factor of 6 is expected after a minor geometry modification and decrease in polyethylene temperature to 25 K. This novel capability will be used to conduct total thermal neutron cross section measurements from 0.0005–10 eV for different materials including moderator materials.

Keywords: Scattering kernels, cold polyethylene, sub-thermal neutron flux

DOI: 10.3233/JNR-210010

Journal: Journal of Neutron Research, vol. 23, no. 2-3, pp. 179-184, 2021