The superconducting transition-edge sensor (TES) is currently one of the most attractive choices for ultra-high resolution calorimetry in the keV x-ray band, and is being considered for future ESA and NASA missions. We have performed a study on the noise characteristics of Au/Ti bilayer TESs, at operating temperatures around ~100 mK, with the SQUID readout at 1.5 K. Experimental results indicate that without modifications the back-action noise from the SQUID chip degrades the noise characteristics significantly. We present a simple and effective solution to the problem: by installing an extra shunt resistor which absorbs the excess radiation from the SQUID input, we have reduced the excess thermal (photon) noise power down by approximately a factor of five, allowing high resolution operation of the sensors.
- transition edge sensors
- superconducting microwave devices
- superconducting transistors
Maasilta, I. J., Kinnunen, K. M., Nuottajärvi, A. K., Leppäniemi, J., & Luukanen, A. (2006). Operation of transition-edge sensors with excess thermal noise. Superconductor Science and Technology, 19, S242-S245. https://doi.org/10.1088/0953-2048/19/5/S16