Jul 22 – 26, 2019
Europe/Rome timezone

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

Jul 25, 2019, 2:15 PM
Auditorium G. Testori (Milano)

Auditorium G. Testori


Piazza Città di Lombardia, 1, 20124 Milano MI
Oral Presentation Low Temperature Detector fabrication techniques and materials Orals LM 003


Stephen Smith (NASA GSFC / UMBC)


We report on the development of large format arrays using multiabsorber transition edge sensors (TESs), commonly 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 the development of very large format arrays without the prohibitive increase in bias and read-out components associated with arrays on individual TES pixels. These devices are under development for the next generation of space telescope such as Lynx. Lynx is a mission concept under study for the Astro 2020 decadal review that will revolutionize x-ray astronomy by combining a < 1” angular resolution optic with 100,000-pixel microcalorimeter array that will achieve ~3 eV energy resolution in the soft x-ray energy range.

Here we present the design optimization and trade-off’s between key performance metrics such as resolution, position-discrimination and count-rate for multiabsorber TESs with up to 25-pixels/hydra. We present results from prototype hydras with pixels on a 25 micron and 50 micron pitch. Arrays incorporate, for the first time, microstrip buried wiring layers of suitable pitch and density required to readout a full-scale Lynx array. The average spectral energy resolution across all 25 pixels was <ΔEFWHM> = 2.51±0.97 eV and <ΔEFWHM> = 3.44±1.00 eV at an energy of 1.25 keV for the 25 and 50 micron pitch designs respectively.

To match the bandwidth and dynamic range requirements of the state-of-the-art multiplexing schemes TESs are typically operated in or close-to critical damping. Although some inductance can be used to reduce the pulse slew-rate it is undesirable to critically damp the hydra since this would suppress the position discrimination. We examine the trade-off between position discrimination and pulse slew-rate and explore alternative approaches to slow the pulse rise-time by optimization of the thermal design.

Student (Ph.D., M.Sc. or B.Sc.) N
Less than 5 years of experience since completion of Ph.D N

Primary authors

Stephen Smith (NASA GSFC / UMBC) Dr Joseph S. Adams (NASA-GSFC / UMBC) Dr Simon, R. Bandler (NASA-GSFC) Sophie Beaumont Dr James, A. Chervenak Aaron Datesman (NASA Goddard space flight center / Science Systems and Applications, Inc.) Dr Fred, M. Finkbeiner (NASA-GSFC / Sigma Space Corp.) Dr Ruslan Hummatov (NASA-GSFC / UMBC) Dr Richard, L Kelley (NASA-GSFC) Dr Caroline Kilbourne (NASA-GSFC) Antoine Miniussi (NASA/GSFC - UMBC) Dr Frederick, S. Porter (NASA-GSFC) Dr John, E. Sadleir (NASA-GSFC) Kazuhiro Sakai (NASA/GSFC) Dr Nicholas, A. Wakeham (NASA-GSFC / UMBC) Dr Edward, J. Wassell (NASA-GSFC / KBRwyle) Dr Michael Witthoeft (NASA GSFC) Dr Kevin Ryu (MIT Lincoln Labs)

Presentation materials