The Bern Cryogenic Detector System for dark matter search

In this paper we report on the design, construction, and operation of a cryogenic system designed to cool a Superheated Superconducting Granule (SSG) detector for dark matter search. The volume accommodating SSG detector is 20 cm in diameter and 67 cm long. The system provides a lowest operating temperature of 115 mK for long-lasting (several months) experiments in the Bern Underground Laboratory.