Towards 100,000-pixel microcalorimeter arrays using multi-absorber transition-edge sensors

TL;DR

This paper presents the development of multi-absorber transition-edge sensors, called hydras, enabling large-format x-ray detector arrays with position encoding, suitable for space telescopes like Lynx, achieving high energy resolution with 25-pixel prototypes.

Contribution

Introduction of hydras, multi-absorber TES arrays with position encoding, supporting large-scale, high-resolution x-ray detection for space telescopes.

Findings

Achieved 1.66 eV energy resolution with 25-pixel array at 1.5 keV.

Demonstrated position discrimination through pulse rise-time analysis.

Developed microstrip wiring for full-scale Lynx array readout.

Abstract

We report on the development of multi-absorber transition edge sensors (TESs), referred to as hydras. A hydra consists of multiple x-ray absorbers each with a different thermal conductance to a TES. Position information is encoded in the pulse shape. With some trade-off in performance, hydras enable very large format arrays without the prohibitive increase in bias and read-out components associated with arrays of individual TESs. Hydras are under development for the next generation of space telescope such as Lynx. Lynx is a NASA concept under study that will combine a < 1 arcsecond angular resolution optic with 100,000-pixel microcalorimeter array with energy resolution of deltaE_FWHM ~ 3 eV in the soft x-ray energy range. We present first results from hydras with 25-pixels for Lynx. Designs with absorbers on a 25 micron and 50 micron pitch are studied. Arrays incorporate, for the first time, microstrip buried wiring layers of suitable pitch and density required to readout a full-scale Lynx array. The resolution from the coadded energy histogram including all 25-pixels was deltaE_FWHM = 1.66+/-0.02 eV and 3.34+/-0.06 eV at an energy of 1.5 keV for the 25 micron and 50 micron absorber designs respectively. Position discrimination is demonstrated from parameterization of the rise-time.