Low-Noise Amplifiers and Superconducting Flex Circuits for Frequency Domain Multiplexed Readout of Detector Arrays

The next-generation ground-based cosmic microwave background (CMB) experimental program aims to provide definitive measurements of the early universe using telescopes configured with large focal plane arrays requiring ~100,000 detectors and associated readout amplifiers and interconnecting components that are currently unavailable commercially. We describe a research plan to develop low-noise cryogenic amplifiers based on series SQUID arrays for frequency domain multiplexed readout of large numbers of CMB detectors, and robust superconducting flex cables that will simplify cryogenic systems integration for large CMB instruments, along with a plan to develop large-scale production processes for these components. We have developed several prototype series SQUID array amplifier designs that exhibit excellent performance characteristics, and processes for the fabrication of robust superconducting flex cables. Both developments meet or exceed the Phase I technical objectives. In Phase II, we will refine and improve the prototype Phase I SQUID array amplifier designs and processes developed for superconducting flex cable production, and transition both processes for compatibility with 6" wafers to improve throughput. By the conclusion of Phase II, we expect to have all infrastructure, processes, and controls in place for high volume manufacturing of these components in order to meet CMB instrumentation and related industrial applications needs. The technologies to be developed will have direct applicability to commercial products and market applications STAR Cryoelectronics currently serves, including instrumentation for biomedical imaging, non-destructive testing of materials, and geophysical exploration. In particular, we anticipate that the proposed low-noise cryogenic amplifiers and superconducting flex cables will enable the company to improve two types of X-ray spectrometers for materials analysis and basic research that the company currently offers. These instruments are in demand by semiconductor manufacturers and researchers at synchrotron facilities. Measurements of the cosmic microwave background (CMB) are helping us understand the origins of the universe and answer fundamental physics questions, foundational research that is at the core of humankind’s unending quest to understand our universe. The proposed research will support the development of large-scale CMB measurement instruments