Low-Power Radiation-Hard ADC for Detector Readout

Fast, low-power, low-noise, high-sensitivity, and radiation-resistant electronic instrumentation is an essential component for readout of cryogenic detectors. Currently, cryogenic detector readout instrumentation measures the energy associated with the response of detectors such as Transaction Edge Sensors (TES), Superconducting Tunnel Junction (STJ), Visible Light Photon Counters (VLPC) and bolometers operating at low temperatures. The most prevalent method uses analog SQUID amplifiers coupled to these detectors to transfer the signal to room temperature analog-to-digital converters (ADCs). Unfortunately, this analog readout approach is extremely sensitive to noise pickup, cross-talk in the analog link to room temperatures. Furthermore, it requires precision cryopackaging techniques to manage heat load and maintain fidelity in the analog data link. We propose to develop a high performance ADC based on Energy-Efficient Rapid Single Flux Quantum (ERSFQ) class of superconductor electronics. ERSFQ technology is developed for low-power operation with sub-attoJoule energy dissipation per logic switching. This leads to more than two orders of magnitude reduction in power dissipation in comparison to standard RSFQ technology. Therefore, ERSFQ-based digitizers can be placed on the same mK stage hosting the cryocooled detector without compromising its operation, and ensuring maximum signal-to-noise ratio. In Phase I of this project, we propose building a single-channel digitizer based on ERSFQ technology. This digitizer will be integrated into a multi-channel system with FPGA-based interface in Phase II. Commercial Applications and Other Benefits Once developed, this cryogenic readout detector system can be modified for more mainstream commercial applications such as superconductor microbolometer-based THz detector system readout for medical and security imaging applications