Dilution Fridge for Particle Physics

The Physical Institute of the University of Zurich is planning to acquire a dilution refrigerator (DF) to develop superconducting sensors for use in particle physics and the search for light dark matter (DM). The DF will operate a two-component payload: 1) superconducting sensors such as TES or SNSPDs, including detector targets (Si, Sapphire, He) with masses ranging from grams to kilograms; 2) SQUID readout electronics in close proximity to the sensors. Both the sensors and SQUIDs must be free from magnetic fields. The base temperature at the mixing chamber must be below 10 mK with a cooling power of at least 400 μW, and at 100 mK, it must maintain at least 400 μW. The experiment should be capable of maintaining its base temperature for at least three months of continuous operation. The DF requires mechanical pre-cooling to avoid external coolants, except for small amounts of liquid nitrogen for the gas system. The He3/He4 mixture in the dilution unit should operate in a closed loop. The control and software system of the DF should be autonomous and capable of allowing operation and data acquisition via network. The DF should exhibit minimal vibrations at the mixing chamber. To minimize vibrations from the pumps and compressors of the cooling circuit, we need to be able to mount the pulse tube and compressors separately from the cryostat. Upon delivery of the device, compliance with all requirements must be demonstrated.