Performance of the near-infrared camera for the Subaru Prime Focus Spectrograph

Stephen A. Smee, James E. Gunn, Robert H. Barkhouser, Josh Peebles, Craig P. Loomis, Eddie Bergeron, Kjetil Dohlen, Erin Kado-Fong, Jahmour J. Givans, Mirek Golebiowski, Aidan Gray, Randy P. Hammond, Stephen C. Hope, Robert Lupton, Yuki Moritani, Naoyuki Tamura

Research output: Chapter in Book/Report/Conference proceedingConference contribution


This paper presents thermal system and imaging performance test results from the first of four near infrared cameras for the SuMIRe (Subaru Measurement of Images and Redshifts) Prime Focus Spectrograph (PFS) being developed for the Subaru Telescope. The PFS near infrared camera is a large (330 mm entrance aperture to accommodate a 275 mm collimated beam diameter) cryogenically cooled vacuum Schmidt camera with a 300 mm focal length that images dispersed light onto a 4k x 4k, 15 µm pixel, HgCdTe substrate-removed Teledyne 1.7 µm detector. The 230 kg camera contains just four optical elements: a two-element refractive corrector, a Mangin mirror, and a field flattening lens. This simple optical design produces good imaging performance considering the wide field and wavelength range, and it does so in large part due to the use of a Mangin mirror for the Schmidt primary. Thermal background, both in-band and out-of-band, is reduced to a scientifically acceptable level using cryogenically cooled optics, very black geometrically optimized baffling, and a pair of thermal rejection coatings that reject photons between the edge of the science bandpass and the detector cutoff. System operating temperature is achieved by a pair of closed-cycle cryocoolers, one dedicated to cooling the optics, and one dedicated to cooling the detector. Here we discuss the lab performance of the near infrared camera, both from the perspective of the thermal system and the optical system, including in-band and out-of-band performance.

Original languageEnglish (US)
Title of host publicationGround-based and Airborne Instrumentation for Astronomy IX
EditorsChristopher J. Evans, Julia J. Bryant, Kentaro Motohara
ISBN (Electronic)9781510653498
StatePublished - 2022
EventGround-based and Airborne Instrumentation for Astronomy IX 2022 - Montreal, Canada
Duration: Jul 17 2022Jul 22 2022

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


ConferenceGround-based and Airborne Instrumentation for Astronomy IX 2022

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


  • Cryogenic
  • HgCdTe
  • Multi-object spectrograph
  • Near infrared camera
  • Spectrograph
  • Subaru Telescope
  • SuMIRe


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