Frequency domain multiplexing (fMUX) is a mature readout scheme for TES detectors in the millimetre and sub-millimetre bands. It is implemented at MHz carrier frequencies for the South Pole Telescope, POLARBEAR, and Simons Array, and is planned for deployment on the LiteBIRD space polarimeter. Existing implementations couple to the detectors with low-noise, low-input impedance SQUID transimpedance amplifiers, and complex arrangements are in place to handle the inherent SQUID non-linearity and tuning requirements.
We introduce a new cryogenic amplification scheme that couples the multiplexed TES devices to a traditional FET amplifier using a high turns-ratio, wide-band, cryogenic transformer that steps up the TES impedance to the noise match of the amplifier. We characterize the bandwidth, transimpedance, input impedance, and noise of the transformer-coupled fMUX system to demonstrate that it is a promising candidate for SQUIDless MHz frequency domain multiplexing.
|Less than 5 years of experience since completion of Ph.D||Y|
|Student (Ph.D., M.Sc. or B.Sc.)||Y|