Sandia National Labs Academic Programs Collaboration Report

Exploring innovative fabrication methods for gamma-ray detecting microcalorimeters

Experts at Sandia’s Microsystems Engineering, Science and Applications (MESA) Complex and Texas A&M’s AggieFab are looking into the unique challenges associated with design and fabrication of low-temperature, microfabricated, radiation detection systems, specifically gamma-ray detecting microcalorimeters. A microcalorimeter consists of a superconductor, known as a transition edge sensor (TES), attached to an absorbing medium in pixelated arrays, which are held at cryogenic temperatures. When a photon interacts in the absorbing medium, the heat produced is proportional to the energy of the particle, which is read out using the TES. While results such as ultra-high resolution measurements of plutonium have been achieved, fundamental understanding of key system components in microcalorimeters is lacking. Several significant

accomplishments emerged from this three-year project entitled, “Investigating Microcalorimeter Photon Detector Performance to Enable Use in Nonproliferation Applications,” led by Sandia PI Michael Hamel and Texas A&M collaborator Han Arum. These include a complete analysis of tin absorbers showing a strong preferred lattice orientation, and the creation of a new method to fabricate and integrate an array of absorbers and TES, which resulted in the filing of two provisional patents. A preliminary absorber design is being tested. This research could help detect and assess nuclear materials and support numerous mission objectives and programs.

The Microsystems and Engineering Sciences Applications (MESA) Complex’s initial mission is to produce electronic circuits and computer chips designed to withstand high levels of radiation. These “hardened” electronics are critical to national security needs.

43

2021-2022 Collaboration Report