Investigation Of Microcalorimeter Absorber Performance

This work seeks to expand the performance of microcalorimeter gamma-ray detectors such that they are applicable to the wide array of radiation detection needs for nuclear material characterization. We investigated the performance of existing tin absorbers used in microcalorimeter detectors designed by the National Institute of Standards and Technology (NIST) and Los Alamos National Laboratory (LANL). Using this analysis, which included energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD), samples of tin absorbers that provided superior photopeak resolution were compared to those that provided worse resolution. Samples providing the best resolution showed a particular preferred orientation in the crystal lattice structure and large grain sizes, while samples providing worse resolution showed different orientations with small grain sizes. It is hypothesized that the crystal lattice orientation and grain size may produce the differing performance. We are seeking a fabrication process that will produce tin absorbers with what we hypothesize are good properties. A commercial electrodeposition process was found and absorbers measuring 380 – 400 μm thick were fabricated. This paper will provide an overview of the project including research objectives as well as current progress and results.This work seeks to expand the performance of microcalorimeter gamma-ray detectors such that they are applicable to the wide array of radiation detection needs for nuclear material characterization. We investigated the performance of existing tin absorbers used in microcalorimeter detectors designed by the National Institute of Standards and Technology (NIST) and Los Alamos National Laboratory (LANL). Using this analysis, which included energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD), samples of tin absorbers that provided superior photopeak resolution were compared to those that provided worse resolution. Samples providing the best resolution showed a particular preferred orientation in the crystal lattice structure and large grain sizes, while samples providing worse resolution showed different orientations with small grain sizes. It is hypothesized that the crystal lattice orientation and grain size may produce the differing performance. We are seeking a fabrication process that will produce tin absorbers with what we hypothesize are good properties. A commercial electrodeposition process was found and absorbers measuring 380 – 400 μm thick were fabricated. This paper will provide an overview of the project including research objectives as well as current progress and results.