PACS Instrument

The PACS instrument (Photoconductor Array Camera and Spectrometer) was built by the German Max Planck Institute for Extraterrestrial Physics (MPE) and a team led by the Institute’s A. Poglitsch. It comprises two elements:

  • An imaging photometer composed of two sensors working simultaneously (the first at either 60 to 85 µm for blue, and the second at 130 to 210 µm for red) with two spider web bolometer arrays cooled to 300 mK (respectively 32x16 and 64x32 pixels).
  • And a spectrometer operating on a 57 to 210 µm wavelength band over 5x5 pixels, with sensors composed of 2 Ge/Ga 16x25 pixels photoconductor grid.

PACS photometer spectrometer field PACS scheme
PACS 3D scheme

French contribution to the PACS instrument was delivered by 3 CEA laboratories: Astrophysics Divison (SAp), LETI, and the Low Temperatures Division (SBT).

The CEA’s Astrophysics Division contributed by providing:

  • the Photometer Focal Plane Unit (PhFPU) comprising:
    • two focal planes (blue and red) complete with bolometer arrays developed and manufactured by the CEA/LETI,
    • a 300 mK cryo cooler built by the CEA/SBT,
    • a thermal strap and a frame.
PACS PhotometerCredits CNES/CEA
  • the Bolometer Controller unit (BOLC), a warm electronics (WE) module to control the PhFPU in charge of:
    • reading bolometer arrays and amplifying the signal,
    • monitoring and controlling the cryo cooler,
    • and reading the surveillance parameters.