Published: January 27, 2012
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 ESAs Athena X-ray observatory is straightforwardly achievable, including engineering margin, with present NIST readout parameters.
Citation: Journal of Low Temperature Physics
Pub Type: Journals
transition-edge sensor, SQUID multiplexer, X-ray microcalorimeter
Created January 27, 2012, Updated November 10, 2018