Transition-edge sensor microcalorimeter detectors for future X-ray and gamma-ray mission

Transition-edge sensor (TES) microcalorimeters have growing applications in X-ray and gamma-ray astronomy due to their high energy resolution and fast rates of time-stamping of individual photons. We are testing and optimizing a 32-pixels SLEDGEHAMMER (Spectrometer to Leverage Extensive Development of Gamma-ray TESs for Huge Arrays using Microwave Multiplexed Enabled Readout) detector developed by the quantum sensor group at the National Institute of Standards and Technology (NIST). TES arrays can achieve energy resolutions of 55 eV FWHM (Full Width Half Maximum) at 97 keV [Bennett et al. 2012]. This SLEDGEHAMMER detector has 32 microwave resonators inductively coupled with 32 Superconducting Quantum Interference Device (SQUIDs) and SQUIDs are coupled with 32 Mo-Au TESs. Each TES is thermally coupled to a 1.4×1.4×0.38 mm Sn absorber pixel to absorb gamma-ray photons. A few SLEDGEHAMMER arrays can be used in the focal plane of balloon as well as space-borne telescopes i.e., 511 keV gamma-ray camera (511 keV gamma-ray CAmera using Microcalorimeters, Krawczynski et al. 2021) enabling hard X-ray imaging spectroscopic observations of astrophysical sources with unprecedented energy resolutions. We will report here on the energy resolution, pixel to pixel cross talking, noise in the detector channels and etc., using a 50 μm collimated X-ray beam and other board sources along with the application in the 511 keV gamma-ray camera balloon flight to examine the source of the 511 keV gamma-ray emission from the galactic center.