Radioargon production through the irradiation of calcium oxide

The production of radioargon through the irradiation of CaO was performed in an in-core facility within the The University of Texas at Austin MARK II TRIGA reactor. The major radioargon isotope produced was 37Ar via the 40Ca(n,α)37Ar reaction pathway. The CaO powder was vacuumed sealed in a quartz ampoule. The sample was irradiated in a Cd-lined Al alloy canister for 2 h at 500 kW. After the irradiation, the sample was counted using an HPGe detector five times with increasing count times. 41Ar, 42K, 43K, and 47Ca were detected in the spectra. The induced activities of 37Ar, 39Ar, 41Ar, 42K, 43K, and 47Ca were calculated using a 63-group energy-dependent neutron flux determined utilizing a neutron energy flux profile calculated from a MCNPX model of the TRIGA reactor core. The production ratios generated from the model allowed for the estimation of induced 37Ar and 39Ar activities through the measured induced activities of 41Ar, 42K, 43K, and 47Ca.