Improvements in superconductor device fabrication, detector hybridization techniques, and
superconducting quantum interference device readout have made square-centimeter-sized
arrays of gamma-ray microcalorimeters, based on transition-edge sensors (TESs), possible.
At these collecting areas, gamma microcalorimeters can utilize their unprecedented energy
resolution to perform spectroscopy in a number of applications that are limited by closely-
spaced spectral peaks, for example, the nondestructive analysis of nuclear materials. We …