Focal Plane Array Alignment and Cryogenic Surface Topography Measurements for the Prime Focus Spectrograph

Abstract

We describe the infrastructure developed to align and measure the focal plane arrays (FPA) for the Subaru Measurement of Images and Redshifts (SuMIRe) Prime Focus Spectrograph (PFS), and detail the results of these efforts at ambient and operating temperatures. PFS will employ four three-channel spectrographs with an operating wavelength range of 380 nm to 1260 nm. Each spectrograph will be comprised of two visible channels and one near infrared (NIR) channel, and each channel will use individual Schmidt cameras to image the captured spectra onto their respective detectors. In the visible channels, Hamamatsu 2k x 4k charge coupled devices (CCDs) will be mounted in pairs to create a 4k x 4k mosaic, while the NIR channel will use a single Teledyne H4RG 4k x 4k Mercury Cadmium Telluride (HgCdTe) complementary metal oxide semiconductor (CMOS) device.