Thermal kinetic inductance detectors for CMB and sub millimeter observations (Conference Presentation)

We are developing Thermal Kinetic Inductance Detector (TKID) bolometers for submillimter astronomy and CMB polarimetry with the BICEP Array's 250GHz dust monitor camera as an early application. We couple power to our bolometers by resistive terminations to antenna-fed microstrip circuits and sense changes in temperature with a membrane isolated microwave kinetic inductance thermometer (MKIT). The MKIT resonates with an off-island capacitor and capacitively couples to a microstrip transmission line to provide radio-frequency multiplexing analogous to that of traditional non-phonon-mediated KIDs. By splitting the absorption, sensing, and relaxation of quasiparticles back to the thermal bath into different sub-devices, we attain more design degrees of freedom than KIDs and can tailor the detector’s performance. We will report on the design and performance of our optically coupled TKIDs and comment on the sensitivity, emphasizing TLS and vibrational noise mechanisms. We will also show preliminary results from studies of the detectors optical properties as defined by the antenna-array the coupled power to the detector. Lastly, we will describe designs for a 900 detector pathfinder camera that will precede the full 20,000 BICEP Array camera