UKSBS PR18083 AN

This is an Award Notice. MOONS (Multi-Object Optical and Near Infrared Spectrograph) is a new concept for an astronomical instrument that has been selected by the European Southern Observatory (ESO) in response to their call for 3rd generation instruments for the Very Large Telescope (VLT) located at the Paranal Observatory in Chile.

STFC (via the UKATC) is the lead organisation of the Consortium responsible for the design, build and commissioning of the instrument under an ESO Contract, with a budget of around 10M EUR and 200 FTE. As part of this, the UKATC has to deliver the MOONS cryo-vacuum system which requires 2-off turbo pumps for which ESO has mandated the use of a specific model and type, namely the ATH 2303M from Pfeiffer Vacuum.

MOONS is designed to operate at infra-red wavelengths and hence uses detectors that are sensitive to infra-red light. These detectors must be cooled to 120K to limit the background radiation they see and hence must be located inside a cryostat held under vacuum conditions.

To achieve the required vacuum pressure of 1x10-6 mBar the cryostat for MOONS needs 2-off turbo pumps. Based on the demands of on-site maintenance and inter-operability with existing equipment, ESO has mandated that only one specific type of turbo pump can be used at the telescope facility.