Results and Limits of Time Division Multiplexing for the BICEP Array High Frequency Receivers

Time-Division Multiplexing is the readout architecture of choice for manyground and space experiments, as it is a very mature technology with provenoutstanding low-frequency noise stability, which represents a central challengein multiplexing. Once fully populated, each of the two BICEP Array highfrequency receivers, observing at 150GHz and 220/270GHz, will have 7776 TESdetectors tiled on the focal plane. The constraints set by these two receiversrequired a redesign of the warm readout electronics. The new version of thestandard Multi Channel Electronics, developed and built at the University ofBritish Columbia, is presented here for the first time. BICEP Array operatesTime Division Multiplexing readout technology to the limits of its capabilitiesin terms of multiplexing rate, noise and crosstalk, and applies them inrigorously demanding scientific application requiring extreme noise performanceand systematic error control. Future experiments like CMB-S4 plan to use TESbolometers with Time Division/SQUID-based readout for an even larger number ofdetectors.