Cryogenic cooling services for the Thirty Meter Telescope

The Thirty Meter Telescope (TMT) has three instruments in development for first light, and another 6 notional instruments planned for implementation over the first decade of operations. All of these instruments require cryogenic cooling of detectors, as well as optics in most cases. This paper describes the instrument cooling capacity requirements, the trade study that led to the design solution, and the overall layout of the conceptual design. TMT has chosen to build an on-site liquid nitrogen generation plant, and supply liquid nitrogen to the instruments using an autofill system. TMT also supplies compressed helium to instruments with cryocoolers for optics and detectors that require cooling below the boiling point of liquid nitrogen.