Journal Article

Toward Large Field-Of-View High-Resolution X-Ray Imaging Spectrometers: Microwave Multiplexed Readout of 28 TES Microcalorimeters

Ullom, J. N., Sakai, K., Gard, J. D., Miniussi, A. R., Datesman, A. M., Swetz, D. S., Porter, F. S., Finkbeiner, F. M., Eckart, M. E., Bennett, D. A., Noroozian, O., Wassell, E. J., Smith, S. J., Bandler, S. R., Kelley, R. L., Moseley, S. H., Reintsema, C. D., Wollack, E. J., Becker, D., Mates, J. A. B., Yoon, W., Chervenak, J. A., Sadleir, J. E., Vale, L. R., Stevenson, T. R., Fowler, J. W., Hilton, G. D., Wakeham, N. A., Kilbourne, C. A., Adams, J. S.

2018

Overview

We performed small-scale demonstrations at GSFC of high-resolution Xray TES microcalorimeters read out using a microwave SQUID multiplexer. This work is part of our effort to develop detector and readout technologies for future space-based X-ray instruments such as the microcalorimeter spectrometer envisaged for Lynx, a large mission concept under development for the Astro 2020 Decadal Survey. In this paper we describe our experiment, including details of a recently designed, microwave-optimized low-temperature setup that is thermally anchored to the 55mKstage of our laboratory ADR. Using aROACH2 FPGA at room temperature, we read out pixels of a GSFC-built detector array via a NIST-built multiplexer chip with Nb coplanar waveguide resonators coupled to rf-SQUIDs. The resonators are spaced 6 MHz apart (at ∼ 5.9 GHz) and have quality factors of ∼ 15,000. In our initial demonstration, we used flux-ramp modulation frequencies of 125 kHz to read out 5 pixels simultaneously and achieved spectral resolutions of 2.8-3.1 eV FWHM at 5.9 keV. Our subsequent work is ongoing: to-date we have achieved a median spectral resolution of 3.4 eV FWHM at 5.9 keV while reading out 28 pixels simultaneously with flux-ramp frequencies of 160 kHz. We present the measured system-level noise and maximum slew rates and briefly describe our future development work.

• Publisher: Springer Verlag,Springer US,Springer Nature B.V
• Subject: Arrays / Astrophysics / Calorimeters / Characterization and Evaluation of Materials / Cold / Condensed Matter Physics / Coplanar waveguides / Field of view / Heat / High resolution / Image resolution / Imaging spectrometers / Low temperature / Low temperature physics / Magnetic Materials / Magnetism / Multiplexers / Multiplexing / Physics / Physics and Astronomy / Pixels / Resonators / Room temperature / Sensors / Slew rate / Spectral resolution / Spectrometers / Star & galaxy formation / Superconducting quantum interference devices / X-rays