Design, Fabrication and Characterization of Microwave Multiplexing SQUID Prototype

The readout system with a high multiplexing ratio has become a bottleneck limiting the application of large-scale Transition Edge Sensor (TES) detector arrays.

In recent years, the microwave superconducting quantum interference device (SQUID) multiplexer has emerged as a key technology for effectively reading large-scale cryogenic detector arrays.

Currently, the microwave SQUID multiplexer is being adopted by an increasing number of experiments due to its capability of achieving a multiplexing ratio of 2000:1 within the readout bandwidth.

In this study, we developed and fabricated a 32-channel microwave SQUID multiplexer prototype.

And we measured 8 channels of the prototype.

The measured equivalent noise current of the prototype reached 42 pA/$\sqrt{Hz}$.