Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Optimization of the TES-bias circuit for a multiplexed microcalorimeter array



William B. Doriese, Bradley K. Alpert, Joseph W. Fowler, Gene C. Hilton, Alex S. Hojem, Kent D. Irwin, Carl D. Reintsema, Daniel R. Schmidt, Greg Stiehl, Daniel S. Swetz, Joel N. Ullom, Leila R. Vale


In the detector-bias circuit of a transition-edge-sensor (TES) microcalorimeter, the TES-shunt resistor (Rsh) and the thermal conductance to the cryogenic bath (G) are often considered to be interchangeable knobs with which to control detector speed. Indeed, for otherwise-identical TES-parameter models, there are many combinations of Rsh and G that give the same decay-time constants and similar energy resolutions. We present a set of calculations that, given a linear TES model and count-rate and energy-resolution requirements, selects the optimal values of Rsh and G and also determines the required combinations of SQUID-readout noise, multiplexer row-period, and multiplexer row-count to read out the array. We find that low-G, low-Rsh models make multiplexed readout easier. Recent improvements in the NIST time-division-multiplexing architecture have allowed a NIST eight-pixel TES array to be read out with 2.70 eV (full-width at half-maximum) average energy resolution at 6 keV. Finally, we show that the X-rayMicrocalorimeter Spectrometer co-proposed by NASA and NIST for ESA’s Athena X-ray observatory is straightforwardly achievable, including engineering margin, with present NIST readout parameters.
Journal of Low Temperature Physics


transition-edge sensor, SQUID multiplexer, X-ray microcalorimeter


Doriese, W. , Alpert, B. , Fowler, J. , Hilton, G. , Hojem, A. , Irwin, K. , Reintsema, C. , Schmidt, D. , Stiehl, G. , Swetz, D. , Ullom, J. and Vale, L. (2012), Optimization of the TES-bias circuit for a multiplexed microcalorimeter array, Journal of Low Temperature Physics, [online], (Accessed April 19, 2024)
Created January 27, 2012, Updated November 10, 2018