Speaker
Description
The next-generation Cosmic Microwave Background Stage 4 (CMB-S4) survey aims to map the Cosmic Microwave Background with unprecedented sensitivity, probing key areas of fundamental physics such as inflation, exotic light relics, and dark energy. To meet these ambitious objectives, the experiment will deploy approximately 500,000 photon-noise-limited superconducting transition edge sensors (TES) across various large and small aperture telescopes. These TES will operate within cryogenic receivers, requiring multiplexing through low-temperature superconducting quantum interference device (SQUID)-based electronics. SQUID are ultra-sensitive detectors that measure faint magnetic fields, essential for capturing weak CMB signals from the early universe.
To optimize the cryogenic readout for the SQUIDs, the TID-ID Integrated Circuits group at SLAC National Lab has developed R&D amplifiers using state-of-the-art CMOS technologies, including 28 nm and 22 nm FDSOI. These mini-ASICs are engineered for deep cryogenic operation at 4 K, with potential performance at 1 K, allowing for direct interfacing with low-noise SQUIDs housed in cryocoolers. This integration significantly enhances the system's sensitivity by reducing noise and enabling more precise signal detection. By placing the readout electronics at cryogenic temperatures rather than room temperature, the system benefits from minimized cabling, improved signal-to-noise ratio (SNR), and a reduced thermal load on the cryostat. Supported by the LDRD program, these low-power, ultra-low-noise amplifiers, with simulated noise as low as 0.3 nV/√Hz, will be characterized in 2025, laying the groundwork for future System-on-Chip (SoC) ASIC developments tailored for extreme cryogenic environments.
