Development of fast, background-limited transition-edge sensors for the background-limited infrared/sub-mm spectrograph (BLISS) for SPICA

Abstract

We report experimental progress toward demonstrating background-limited arrays of membrane-isolated transition-edge sensors (TESs) for the Background Limited Infrared/Sub-mm Spectrograph (BLISS). BLISS is a space-borne instrument with grating spectrometers for wavelengths λ= 35-435µm and with R=λ/Δλ~500. The goals for BLISS TESs are: noise equivalent power (NEP) = 5×10-20 W/Hz 1/2 and response time τ<30ms. We expect background-limited performance from bilayers TESs with T C =65mK and G=15fW/K. However, such TESs cannot be operated at 50mK unless stray power on the devices, or dark power P D , is less than 200aW. We describe criteria for measuring P D that requires accurate knowledge of T C. Ultimately, we fabricated superconducting thermistors from Ir (T C ≥135mK) and Mo/Cu proximitized bilayers, where T C is the thermistor transition temperature. We measured the Ir TES arrays in our 45mK base temperature adiabatic demagnetization refrigerator test system, which can measure up to eight 1x32 arrays simultaneously using a time-division multiplexer, as well as our single-pixel test system which can measure down to 15mK. In our previous Ir array measurements our best reported performance was NEP=2.5×10-19 W/Hz

SPICA—A Large Cryogenic Infrared Space Telescope: Unveiling the Obscured Universe

“…The Very Long Wavelength Grating module is shown in the right panel of Figure 11 as an example of the GM design. SAFARI employs the latest generation of ultrasensitive TES to detect the incoming photons Audley et al, 2016;Suzuki et al, 2016;Goldie et al, 2012;Beyer et al, 2012). TES bolometers fabricated at SRON have already demonstrated the required NEP , as well as the required optical efficiency (Audley et al, 2016).…”

“…SAFARI employs the latest generation of ultra-sensitive TES to detect the incoming photons (Khosropanah et al 2016;Audley et al 2016;Suzuki et al 2016;Goldie et al 2012;Beyer et al 2012). TES bolometers fabricated at SRON (Ridder et al 2016) have already demonstrated the required NEP (Khosropanah et al 2016), as well as the required optical efficiency (Audley et al 2016).…”