How to Simultaneously Read Out Thousands of sub-Kelvin Transition Edge Sensors in Space

Tijmen de Haan（ティメン・デ・ハーン）
High Energy Accelerator Research Organization

TES bolometers have emerged as a very successful technology in part thanks to their exquisite sensitivity and ability to be fabricated in large monolithic arrays. This technological advancement has enabled the cosmic microwave background satellite LiteBIRD, which is planned for launch in the 2020s. Over 5000 TES bolometers will be flown in presence of tight constraints, including a challenging power budget and stringent signal-to-noise requirements. In order to read out these bolometers without spoiling the instrument's exquisite sensitivity, I have led several advances in frequency-multiplexed (fMux) readout technology. fMux has been demonstrated to great success with an O(10) multiplexing factor, and is currently also operating successfully at a multiplexing factor of 68 on the ground-based telescope SPT-3G. I will discuss a series of improvements that greatly simplify the fMux readout architecture, improve performance, and increase the multiplexing factor. I will present results on several aspects that include digital active nulling, a purely reactive bias circuit, and the moving of the 4K SQUID amplifier to the sub-Kelvin stage.

Place: New Bldg. A 2F Conf. room A（1257） / 新A棟２階会議室A（1257号室）