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Jul 22 – 26, 2019
Europe/Rome timezone

A 960-pixel X-ray-TES readout platform for Athena X-IFU development

Jul 25, 2019, 5:45 PM
1h 15m
Piazza Città di Lombardia (Milano)

Piazza Città di Lombardia


Piazza Città di Lombardia, 1, 20124 Milano MI
Poster Detector readout, signal processing, and related technologies Poster session


W. Bertrand (Randy) Doriese (NIST)


The X-ray Integral Field Unit (X-IFU) is an imaging spectrometer of 3,168 X-ray transition-edge sensors (TESs) under development for ESA’s Athena satellite mission. Our time-division SQUID multiplexing (TDM) architecture is a backup readout option for X-IFU. In TDM, each dc-biased TES is coupled to its own first-stage SQUID (SQ1). The SQ1s are turned on and off sequentially such that one TES at a time is read out per column. Recent work on the 3-column by 40-row scale has shown that TDM can meet all of X-IFU’s requirements, so the next challenge is to demonstrate TDM readout on a scale closer to the final array size. In this vein, we are developing a new 960-pixel readout platform (24 readout columns of 40 multiplexed rows) that is designed to screen X-IFU TES arrays and to develop and test 40-row TDM readout. When the system comes online in 2019, it will contain the largest multiplexed array of X-ray TESs built to date.

Also under consideration for X-IFU is a hybrid scheme of TDM and flux-summing code-division multiplexing (CDM) that we call “hybrid CDM.” In flux-summing CDM, each dc-biased TES is coupled to all SQ1s in the column with coupling polarities that form a row of a Hadamard matrix. CDM’s aliased system noise is a factor of $\surd{N_\rm{rows}}$ lower than TDM’s because in CDM all TESs are read out during all row periods. Our proposed hybrid-CDM scheme will allow a multiplexing factor of 64 with slightly lower readout noise than in 40-row TDM. A new row-addressing scheme, in which each SQ1 has a pair of flux-actuated switches, will allow operation of the 64 SQ1s per column with the 40 row-address lines available in the 24x40 platform.

In this presentation we discuss the design of the 960-pixel platform, with a focus on improvements over NIST’s previous-generation 8-column X 32-row TDM architecture.

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

Primary authors

W. Bertrand (Randy) Doriese (NIST) on behalf of the U.S. Athena X-IFU collaboration (NASA/GSFC, Stanford U., NIST, and U. Colorado)

Presentation materials