Characterization of Transition Edge Sensors for the Simons Observatory

• Published in: Journal of low temperature physics Vol. 199; no. 3-4; pp. 672 - 680
• Main Authors: Stevens, Jason R., Cothard, Nicholas F., Vavagiakis, Eve M., Ali, Aamir, Arnold, Kam, Austermann, Jason E., Choi, Steve K., Dober, Bradley J., Duell, Cody, Duff, Shannon M., Hilton, Gene C., Ho, Shuay-Pwu Patty, Hoang, Thuong D., Hubmayr, Johannes, Lee, Adrian T., Mangu, Aashrita, Nati, Federico, Niemack, Michael D., Raum, Christopher, Renzullo, Mario, Salatino, Maria, Sasse, Trevor, Simon, Sara M., Staggs, Suzanne, Suzuki, Aritoki, Truitt, Patrick, Ullom, Joel, Vivalda, John, Vissers, Michael R., Walker, Samantha, Westbrook, Benjamin, Wollack, Edward J., Xu, Zhilei, Yohannes, Daniel
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.05.2020; Springer Nature B.V; Springer
• Subjects: Apertures; ASTRONOMY AND ASTROPHYSICS; Big Bang theory; bolometers; Characterization and Evaluation of Materials; Condensed Matter Physics; Cosmic microwave background; Critical temperature; Design specifications; Detectors; Devices; Dilution; Low temperature physics; Magnetic Materials; Magnetism; Observatories; OTHER INSTRUMENTATION; Physics; Physics and Astronomy; Square waves; Superconducting quantum interference devices; Superconductivity; Telescopes; Thermodynamic properties; transition edge sensors; Transition edge sensor; TES; Simons Observatory
• ISSN: 0022-2291; 1573-7357
• DOI: 10.1007/s10909-020-02375-9

The Simons Observatory is building both large (6 m) and small (0.5 m) aperture telescopes in the Atacama Desert in Chile to observe the cosmic microwave background CMB radiation with unprecedented sensitivity. Simons Observatory telescopes in total will use over 60,000 transition edge sensor (TES) detectors spanning center frequencies between 27 and 285 GHz and operating near 100 mK. TES devices have been fabricated for the Simons Observatory by NIST, Berkeley, and HYPRES/SeeQC corporation. Iterations of these devices have been tested cryogenically in order to inform the fabrication of further devices, which will culminate in the final TES designs to be deployed in the field. The detailed design specifications have been independently iterated at each fabrication facility for particular detector frequencies. We present test results for prototype devices, with emphasis on NIST high frequency detectors. A dilution refrigerator was used to achieve the required temperatures. Measurements were taken both with 4-lead resistance measurements and with a time-domain Superconducting Quantum Interference Device (SQUID) multiplexer system. The SQUID readout measurements include analysis of current versus voltage (IV) curves at various temperatures, square wave bias step measurements, and detector noise measurements. Normal resistance, superconducting critical temperature, saturation power, thermal and natural time constants, and thermal properties of the devices are extracted from these measurements.