Multiplexed readout is a practical requirement for the successful deployment of large-scale cryogenic detector arrays in applications ranging from x-ray microanalysis to sub-millimeter astronomy. We report on the development of a time-division SQUID multiplexer (SQUID MUX) to read out transition edge sensors (TES). The investigated SQUID MUX is aimed to form one column of a 32x32 SQUID MUX to read out a 32x32 TES array. The new SQUID MUX is a three-stage configuration. Individual TES pixels inductively couple to 1st stage SQUIDs, which are coupled to a 2nd stage SQUID via a superconducting transformer. The 2st and 2nd stage SQUIDs are integrated on the same chip and are operated at the working temperature of the detectors of about 100 mK. The 2nd stage SQUID is read out by a SQUID series array at 4 K. Compared to former designs the new SQUID MUX reduces both the dissipated power per channel and crosstalk between read out channels. In this paper we discuss the SQUID MUX design and analyze the noise and bandwidth performance of the SQUID multiplexer. Multiplexing of test input signals utilizing a Digital Feedback electronics are demonstrated.
Citation: IEEE Transactions on Applied Superconductivity
Pub Type: Journals
arrays, multiplexing, SQUIDs, cryogenic detector