Fermilab, SLAC, Washington University in St. Louis, and University of Illinois Urbana-Champaign have set up module test cryostats to qualify future CMB-S4 prototype wafers and module components including readout electronics. Fig. 1, below, shows a single wafer test cryostat (cryogenic black-body cold load). Fig. 2 shows Ian Gullett (Case Western) and Cesiley King (WashU) and a newly installed cold load, which is used to measure the optical efficiency of detector modules, at Washington University.
Originally posted in the CMB-S4 February 2023 Newsletter