Design and performance of a high-throughput cryogenic detector system

摘要

The Goddard IRAM Superconducting Millimeter Observer (GISMO) is a new superconducting bolometer array camerafor the IRAM 30 Meter Telescope on Pico Veleta, Spain. GISMO uses a 3He/4He cooler mounted to a liquid He/LN2cryostat to cool the bolometer array and SQUID electronics to an operating temperature of 260mK. The bolometer arrayis based on the backshort-under-grid architecture and features 128 2mm square absorbing pixels. A 101mm diameteranti-reflection coated silicon lens is used to define the beam. A single cold pupil stop prevents warm radiation fromreaching the array, but no other stops are used. In the beam, filters and a cold baffling and stray light suppression systemwere used to define the bandpass and prevent out-of-band radiation to a very high level, including out-of-band radiationleaking through the metal-mesh filters from extreme angles. We present a detailed description of this optical design andits performance. A comprehensive report of the electronics and cryogenic integration are also included.