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Herschel Space Observatory PACS Science Verification Review MPE 22/23 June 2006 Future Tests: PACS Test Facility Capabilities – Cryogenics and OGSE Gerd Jakob GJ / MPE 1 Herschel Space Observatory PACS Science Verification Review MPE 22/23 June 2006 Overview: Test Facility Status for PACS FM ILT The set-up is basically as described in PACS Cryo Test Equipment and OGSE Specification, PACS-ME-DS-002, Issue 1.1 (Status of CQM). -> Document to be updated to FM status comprising following revisions: • • • • • • • Test cryostat: windows and filters Test optics: design features and alignment upgrade H2O vapour cell: new design External blackbody: improvements Point source masks: status New molecular FIR laser source at LENS: first results Test equipment: schematic GJ / MPE 2 Herschel Space Observatory PACS Science Verification Review MPE 22/23 June 2006 Test cryostat (OGSE 3) • TC is equipped with 2 windows: – – • Both windows are either equipped with: – • Quartz glass for optical alignment verification tests: Transmission T~76% for λ>35μm Or with: – • Window 1, diameter 25mm: integr. sphere entrance Window 2, diameter 85mm: external focus entrance PE foil, 1mm thick, for FM ILT: T~80% for λ>35μm Window 1 is equipped with: – A manually operated cryo-shutter at ~90K with 2 positions: • • • Transmission A) open (T=100%) at reference position 0 mm B) closed (T=0%) at reference position 30 mm Window 2 Window 1 Window 2 is equipped with: – A manually operated cryo-shutter at ~100K with 3 positions: • • • – A) FL_E-filter, T~85% for λ>52μm + quartz glass, 0.5mm thick, T~76% for λ>35μm at reference position 8.5 mm B) closed (T=0%) at reference position 98.5 mm C) quartz glass, 0.5mm thick, T~76% for λ>35μm at reference position 198.5 mm 2 fixed filters in series at ~6K (each 2 μm thick mylar foil + Incornel coating): Transmission T~2.4% for λ>35μm, respectively T~0.58% for both filters GJ / MPE • Test cryostat temperature levels: L0 ~ 1.6K for ~7 days (13 LHe tankful) L1 ~ 4.8K for ~2 days (70 LHe tankful) 3 Herschel Space Observatory PACS Science Verification Review MPE 22/23 June 2006 Test optics design • • • • • aperture 4.2K 1. TUFIR input integr. sphere M10 P5 H P H P2 M9 H hall sensor GB gear box MD motor drive M mirror A alignment mirror P pupil F focus BB blackbody CF cryogenic filter CW cryostat window T MD3 M4 M5 M6 IF PC I/F C control T temperature read out P position switch 1 integrating sphere w. light cone 1 external focus access 2 flip mirrors for optical path selection (internal or ext. sources) 1 chopper wheel to chop between BB1 and BB2: fchop_max@5K=0.457Hz 7 Cernox temperature sensors light cone P3 F5 CF T C CW1 F4 CF M8 T T BB2 M7 P4 external calibration sources: T C Temp. range: 5K – 80K Absolute temp. accuracy: +/- 20mK@20K; +/-35mK@50K Thermal stability: <+/-1.25mK@30K; <+/-5mK@50K Power dissipation: 12.5mW@30K; 35mW@50K shutter1 background heater integr.sphere B3 G – test optics housing and baffling system T C point source mask and X/Y translation stage GB2 P T MD2 C chopper wheel C 2. TUFIR input point source F3 H shutter2 – BB1 3. external BB: extented or point source M1 H P T M2 A1 A2 C P1 M3 F2 GB1 flip P mirror C MD1 mech.1 T PACS-FPU 4. water vapour absorption cell with BB CW2 alignment with auto collimator CF – – PACS test cryostat CF • Principal design unchanged to CQM ILT phase 2 cryogenic blackbodies (BB): CF • T align.cube align.device test optics rigid support structure F1 telescope focus Z X T T T 77K liquid helium 4.2K T T T T 1.7K 77K PACS test optics G.Jakob 31.10.03 GJ / MPE IF 4 Herschel Space Observatory PACS Science Verification Review MPE 22/23 June 2006 Test optics alignment (1) • • Complete new optical alignment verification started for FM campaign TO internal alignment complete: optimized imaging qualities and target positions achieved with no vignetting: – BBs and integrating sphere centered on Lyot stop to 1% of diameter each BB2 Ext.focus entrance (window2) BB1 Test optics Int.sphere entrance (window1) PACS FPU Test cryostat GJ / MPE 5 Herschel Space Observatory PACS Science Verification Review MPE 22/23 June 2006 Test optics alignment (2) • Internal and external focus positions verified by use of LED array: – best focus at +/-1mm from design value – Transverse position good to +/-0.2mm • Image quality: Ext. focus target IM1 IM2 LED array – < 3 µm wave front error (PACS) – field distortion less than 1 blue photometer detector pixel for the total chopped PACS field of view Test optics imager 1 and imager 2 with LED array in telescope focus position and target in external focus position GJ / MPE 6 Herschel Space Observatory PACS Science Verification Review MPE 22/23 June 2006 Test optics alignment (3) • • • • • • 1st cryogenic optical alignment verification test at 5 Kelvin successfully performed Cryostat equipped with test optics, PACS mass and optical focus dummy Autocollimator telescope with digital camera aligned with cryostat Additional prism optics mounted to observe through both windows simultaneously 2nd cryogenic reproducibility test planned for June / July Preliminary results (after 1st run): – Stability (300K / 5K) of test optics axis relative to optical bench + PACS dummy: • • – Prism optics ACT ~ 0.1 mm in Y and Z direction (position) < 30” angular Stability (300K / 5K) of test optics + cryostat optical bench relative to external window flange: • • • – cryostat with test optics, PACS mass and optics dummy ~ 1 mm in +Y direction ~ 4 mm in -X direction (uncritical) < 20” angular All measured values within design specs. GJ / MPE Autocollimator telescope (ACT) aligned with test cryostat, test optics and reference prism optics 7 Herschel Space Observatory PACS Science Verification Review MPE 22/23 June 2006 H2O vapour cell • New design with imaging optics, covering the complete chopped PACS field of view: – – – – Ceramics heater with T=800K Thermal stability ~+/-1K Settling time ~1min Cell will be equipped with (only) 1 PE window (instead of 2 compared to CQM ILT) – Gap between cell and cryostat vented with dry N2 gas – Temperature und pressure data available for housekeeping system • Expected improvement (compared to CQM ILT): – 10% deep lines relative to measured continuum for saturated H2O – Improved line contrast of factor ~2-3 • Available for FM ILT to be mounted at test cryostat window 2 position (external focus entrance) GJ / MPE 8 Herschel Space Observatory PACS Science Verification Review MPE 22/23 June 2006 External Blackbody • • • • • • • Improved design with well defined pin holes (point sources) in a black painted surface (no structures) Available pin holes diameters: 0.45 / 0.7 / 1.0 / 1.5 / 2.0 / 4.0 / 10.0 / 15.0 / 25.0 mm Temperature range 300K – 1000K Thermal stability +/-0.25K X/Y-stage position reproducibility <20μm 30-50% improvement of contrast (comp. to CQM ILT) by implementation of N2 gas environment Design description in PACS-MEDS-003 will be updated GJ / MPE External blackbody mounted on X/Y-stage at test cryostat window 2 9 Herschel Space Observatory PACS Science Verification Review MPE 22/23 June 2006 Point source masks • • • • Design description unchanged from CQM ILT See document PACS-ME-DS-003 issue 1 ‘OGSE External Point Source Mask Specification’ Hot plate temperature up to 600K All available hole patterns at their nominal positions in the FOV: Hot plate assembled with X/Y-stage at test Cryostat window 2 •New: 30-50% improvement of contrast by implementation of N2 gas environment GJ / MPE 10 Herschel Space Observatory PACS Science Verification Review MPE 22/23 June 2006 New Molecular FIR Laser Source at LENS (OGSE 4) • LENS is building a new molecular laser system: – – – – • In early May 2006 a performance demonstration at LENS in a pre-test with MPE’s PACS detector set-up was successful: – • CO2 pump laser with ~10 Watts output power; bandwidth 1 MHz FIR output power typically mW for ‘strong lines’ and μW for weaker lines Bandwidth for a FIR line ~ MHz Basic FIR lines are covering the PACS spectral wavelength range Det. dewar FIR CO2 Two available lines were detected: 118.8 μm and 170.5 μm For the FM ILT (Sept-Oct) the final FIR source will be shipped to MPE to be installed with the cryostat optics GJ / MPE Optical bench with CO2 laser and FIR laser source during pre-test with PACS detector module (integrated with blue test dewar) 11 Herschel Space Observatory PACS Science Verification Review MPE 22/23 June 2006 New Molecular FIR Laser Source at LENS # GJ / MPE 1 FREQUENCY (THz) 4.25167 2 3.10594 3 4 5 6 7 2.52278 2.25205 1.75753 1.34135 1.28832 8 1.23478 9 1.18215 WAVELENGTH WAVENUMBER Expected output (cm-1) power (m) 70.511638 141.821 mW (no filter trans) 96.522408 103.603 µW (no filter trans) 118.834107 84.151 mW 133.119600 75.120 µW 170.576394 58.625 mW 223.500 44.743 µW 232.7 42.9738 µW (no det respo) 242.79 41.188 µW (no det respo) 253.6 39.432 µW Initial FIR methanol laser wavelengths for PACS spectral calibration test; further lines are feasible after successful technical upgrade of the laser system 12 Herschel Space Observatory PACS Science Verification Review MPE 22/23 June 2006 FIR laser lines, PACS RSRF and 0.5m air transmission GJ / MPE 13 Herschel Space Observatory PACS Science Verification Review MPE 22/23 June 2006 New Molecular FIR Laser Source, beam input for FM ILT • As successfully demonstrated during the pre-test two different optical set-ups are feasible for PACS FM ILT: – – – • • homogenous array illumination with FIR source and integrating sphere optics single (or multi) pixel illumination with FIR source via external focus entrance (point source) ‘point source’ motion across the slicer Improved air transmission feasible by installation of N2 gas vented light pipe optics Laser power monitoring by EGSE suggested GJ / MPE 14 Herschel Space Observatory PACS Science Verification Review MPE 22/23 June 2006 ILT Test Equipment Schematic vacuum-pump m3/h He-pump RS 232 Pumping unit m3/h CEA 300 K Harness m3/h IEEE/ RS 232 cryostat temp diodes Monitor 218 IEEE cryostat temp sensors Monitor 1 TIC 304 M IEEE Monitor 2 TIC 304 M XY Stage gas cell Scanner 3716 TEST OPTCS 4-300 K Harness ext. BB and controller CRYOBB1 IEEE Hotplate IEEE CRYOVAC PACS FPU Scanner 3716 Temp Sensors Monitor 218 BB1 Controller 370 BB2 Controller 370 IEEE RS 232 IEEE I/F LENS I/F Motor drive electronics IEEE RS 232 1.7 K LHe IEEE RS 232 LHe 4.2 K RS 232 LN2 Testoptics 4 K Harness RS 232 Pressure Monitor PKR 251 RS 232 GJ / MPE SPU testoptics 300 K Harness 4.2 K LHe-Level Model 135 77 K LN2-Level Model 186 DPU PACSTestcryostat 77 K 1.7 K LHe-Level Model 136 BOLC DEC/MEC CSL 300 K Harness CRYOBB2 CRYOVAC P XY-Stage Control PC "Labview" RS 232 IEEE 15