PACS IBDR MPE 27/28 Feb 2002 AIV 1 PACS IBDR Test Cryostat and OGSE Gerd Jakob MPE

PACS IBDR MPE 27/28 Feb 2002 AIV 2 Optical ground support equipment (OGSE) OGSE 1 is used for QM, FM and FS Ge:Ga detector modules performance checks Status: ready for use OGSE 2 is used for Ge:Ga detector modules spectral and proton- irradation tests to be performed at LENS and at PSI Status: ready for use OGSE 3 is used together with a big test cryostat for PACS instrument characterization tests to be performed on CQM+AVM, PFM and FS models during Instrument Level Tests (ILT) -Status: design in progress

PACS IBDR MPE 27/28 Feb 2002 AIV 3 OGSE 3 for PACS instrument characterization Two liquid helium reservoirs: 70l for 4.2K and 13l for 1.7K level 90l liquid nitrogen for thermal shielding Optical bench 1060mm diameter, covered by super-insulated 4.2K thermal shield with 900mm available height Service life 10 hours with full PACS operation, 48 hours with PACS off FIR windows for calibration sources input and optical windows for alignment checks Cryogenic filters to provide operational telescope background Representative cryogenic harness with 1100 wires shields + 30 overshields + ~80 wires and shields for cryostat and test equipment Provide clean instrument environment, payload integration in cleanroom class Status: final specifications by MPE in progress detailed design phase startet at manufacturer Cryovac GmbH PACS cryostat specifications:

PACS IBDR MPE 27/28 Feb 2002 AIV 4 OGSE 3 for PACS instrument characterization ctd. Tolerable overall dimensions: 1400mm diameter, ~max. 2300mm height Specific mounting rack for different cryostat positions PACS cryostat dimensions:

PACS IBDR MPE 27/28 Feb 2002 AIV 5 OGSE 3 for PACS instrument characterization ctd. Opto-mechanical I/F PACS FPU with test optics and optical bench 3x FPU suspension feet on optical bench 4x 1.7K I/F 3x 4.2K I/F Test optics I/F with cryostat windows Test optics I/F with alignment devices 2x cryogenic harness feedthrough at optical bench Harness I/F with FPU 16x vacuum feedthrough 128 pin connectors to warm electronics Mechanical I/F to pumping unit -Status: final definition Cryostat interfaces:

PACS IBDR MPE 27/28 Feb 2002 AIV 6 OGSE 3 for PACS instrument characterization ctd. Herschel telescope simulator test optics integrated with test cryostat, aligned to PACS and operated at 4.2K Image quality goal: 3µm wave front error (  PACS), field distortion less than 1 blue photometer detector pixel for the total chopped PACS field of fiew Complex opto-mechanical imaging and baffling system 3 cryogenic mechanism for filter, mirror and chopper wheels Internal or external calibration source input pre-selected by cryogenic mechanisms 2 internal cryogenic blackbodies TUFIR input in combination with an internal integrating sphere TUFIR input as point source External blackbody, extended or with point source simulator Water vapour absorption cell -Status: detailed optics design Test optics specifications:

PACS IBDR MPE 27/28 Feb 2002 AIV 7 OGSE 3 for PACS instrument characterization ctd. Test optics schematic:

PACS IBDR MPE 27/28 Feb 2002 AIV 8 OGSE 3 for PACS instrument characterization ctd. Initial wavelength calibration with water vapour (or CO gas) absorption cell Absorption path length 300mm, vapour pressure 10–25mbar Hot plate 300K – 600K I/F with cryostat -Status: conceptual design Water vapour absorption cell: Water vapour spectrum for PACS initial wavelength calibration

PACS IBDR MPE 27/28 Feb 2002 AIV 9 OGSE 3 for PACS instrument characterization ctd. Point spread function investigations and grating alignment Translation stage with single point source or pattern masks Blackbody source 300K – 750K I/F with cryostat -Status: conceptual design External blackbody with point source simulator:

PACS IBDR MPE 27/28 Feb 2002 AIV 10 OGSE 3 for PACS instrument characterization ctd. 2 EOI Model cryogenic blackbodies, modified to the specific dimensions of PACS test optics Chopping between two BB to provide a)calibrated signal and b)calibrated background -Status: conceptual design Final wavelength calibration at LENS with a set of ~200 spectral lines Combination of PACS with TUFIR, a tunable high resolution coherent FIR radiation source -Status: interface definition phase Internal blackbodies: TUFIR input (OGSE 4): GHz