CTBT: Science and Technology Conference 2025 - SnT2025

Improving estimates of production rates of 37Ar by measuring the thermal neutron cross section of the 40Ca(n,a)37Ar reaction

P3.6-701

10 Sept 2025, 11:00

1h

Zeremoniensaal

Board: 39

E-poster T3.6 Analysis of Radionuclide Monitoring Data P3.6 Analysis of Radionuclide Monitoring Data

Speaker

Ms Khiloni Shah (The University of Texas at Austin)

Description

Argon-37 is a signature of interest for nuclear explosion monitoring because its longer half-life compared to radioxenon isotopes provides a longer detection window and it is produced in underground nuclear explosions (UNEs) with high enough activity to be detected using current detection systems. 37Ar is produced in UNEs through the neutron activation of 40Ca in rock and soil. The thermal neutron cross section for the 40Ca(n,a)37Ar reaction is poorly characterized, with the Evaluated Nuclear Data File (ENDF) and the Japanese Evaluated Nuclear Data Library (JENDL) disagreeing on what occurs at low energies. Improving the nuclear data by measuring the 40Ca(n,a)37Ar thermal cross section supports the characterization of 37Ar production from UNEs for on-site inspections. To measure the cross section, an experiment was designed and conducted at the University of Texas using a monoenergetic cold neutron beam. Prompt alpha spectroscopy was used to measure the cross section.