The Cryogenic Digital Readout Module with GaAs JFET ICs

In general, it is known that n‐type GaAs JFETs offer good cryogenic performance. This makes them suitable for use with high impedance cryogenic detectors. We designed several kinds of integrated circuits (ICs) with n‐type GaAs JFETs and demonstrated their performance at cryogenic temperatures. Our AC‐coupled capacitive trans‐impedance amplifiers (CTIA) showed good performance. In particular, the input offset voltages were less than +/−0.5 mV. The voltage hold time of the sample‐and‐holds was more than 0.1 seconds. The maximum clock speed of the NAND type shift‐registers was 100 kHz or greater. Power dissipations of each circuit are 0.1–3 μW per one unit. These properties express the possibility to realize the multi‐channel cryogenic digital readout system. We have fabricated 16‐channel AC coupled CTIAs, 32:1 multiplexers with sample‐and‐holds, 32‐channel shift‐registers, and 32‐channel voltage distributors. We describe plans for using this technology in the near future to build a 32‐channel cryogenic digi...