Year
2021
Abstract
238U cumulative fast fission product yields were analyzed from recently measured γ-rays using Godiva-IV as the neutron source. Due to high levels of radiation present after a Godiva-IV pulse, samples are not able to be retrieved and delivered to the γ-ray counting setup until approximately 1 hour after irradiation. Analyzing fission product γ-rays rely heavily γ-ray branching ratios, where the branching ratios were concluded to have discrepancies. A γ-ray counting setup consisting of 4 Compton-suppressed HPGe clover detectors and a new digital data acquisition system is being developed at LLNL for use in a campaign of measurements at the OSU TRIGA reactor. The new setup will provide high γ-ray detection efficiency and high segmentation of the array will increase the γ-γ coincidence detection efficiency and enable the investigation of γ-ray branching ratios. Also, the detection system will be directly connected to the OSU TRIGA rabbit facility to allow for the rapid transport of samples from the core to the counting setup within 3 seconds. An issue with the current rabbit system is that the sample carriers have trace elements that will undergo neutron capture reactions and introduce unnecessary γ-rays. This prompted a study on different polyethylene samples at the OSU TRIGA reactor and the development of a new rabbit sample carrier. A preliminary proof-of-principle measurement at the OSU TRIGA reactor will be presented along with fission products identified within 30 minutes from fission. The setup at LLNL will be described and future measurements will be listed.