Detectors and cryostat design for the SuMIRe Prime Focus Spectrograph (PFS)

摘要

We describe the conceptual design of the camera cryostats, detectors, anddetector readout electronics for the SuMIRe Prime Focus Spectrograph (PFS)being developed for the Subaru telescope. The SuMIRe PFS will consist of fouridentical spectrographs, each receiving 600 fibers from a 2400 fiber roboticpositioner at the prime focus. Each spectrograph will have three channelscovering wavelength ranges 3800 {\AA} - 6700 {\AA}, 6500 {\AA} - 10000 {\AA},and 9700 {\AA} - 13000 {\AA}, with the dispersed light being imaged in eachchannel by a f/1.10 vacuum Schmidt camera. In the blue and red channels a pairof Hamamatsu 2K x 4K edge-buttable CCDs with 15 um pixels are used to form a 4Kx 4K array. For the IR channel, the new Teledyne 4K x 4K, 15 um pixel,mercury-cadmium-telluride sensor with substrate removed for short-wavelengthresponse and a 1.7 um cutoff will be used. Identical detector geometry and anearly identical optical design allow for a common cryostat design with theonly notable difference being the need for a cold radiation shield in the IRcamera to mitigate thermal background. This paper describes the details of thecryostat design and cooling scheme, relevant thermal considerations andanalysis, and discusses the detectors and detector readout electronics.