Multiplexing Readout
Frequency-domain Multiplexing Electronics
In space applications, the internal room of detectors is limited, and the 100mK cryogenic refrigerator have only about 1μW of cooling capacity. Therefore, it is necessary to use multiplexing readout technology to reduce the number of wires required to read out the TES array, in order to control the wiring area and the thermal load caused by the wires.
On DIXE, four frequency-division multiplexing (FDM) readout circuits with a multiplexing ratio of 1:25 are adopted to achieve the readout of the 10×10 TES array signal within an overall area of approximately 12 cm2. A single superconducting wire will simultaneously input bias voltage signals of 25 different frequencies on 1-5 MHz from higher temperature platforms into the TES array at 100 mK. Relying on high-precision micro LC resonators, different bias voltage signals are selected for different TES, thereby modulating their output signals to different frequencies. The modulated signals are collected onto a single superconducting wire again and outputted to a superconducting quantum interference device (SQUID) for preliminary amplification. After low-noise amplification at room temperature, they enter the demodulation circuit to restore the original response of each pixel.
