Vacuum and cryogenic system for the MUSE detectors

MUSE with its 24 detectors distributed over an eight square meter vertical area was requiring a well engineered and extremely reliable cryogenic system. The solution should also use a technology proven to be compatible with the very high sensitivity of the VLT interferometer. A short introduction reviews the various available technologies to cool these 24 chips down to 160 K. The first part of the paper presents the selected concept insisting on the various advantages offered by LN2. In addition to the purely vacuum and cryogenic aspects we highlight some of the most interesting features given by the control system based on a PLC.