Jdry-100-Astra, A Cryogen-Free 3he-4he Dilution Refrigerator For Ground-Based Cosmic Microwave Background Astronomy

A new custom cryogen-free dilution refrigerator with base temperature of 17 mK and cooling power of 120 mu W@100mK was developed in collaboration with the University of Roma (Italy) and Janis Research Company, Inc. (USA). The design is specifically geared for integrating with an existing telescope on alt-azimuth mount. The first lab-based test results show that the system is maintaining its design specifications in its tilted position up to as much as -20 degree and +50 degree from the cryostat vertical axis.