1. PACS IBDR 27/28 Feb 2002 PACS Instrument Overview1 Instrument Design/Development Status and System Performance PACS Instrument Overview A.Poglitsch MPE

2. PACS IBDR 27/28 Feb 2002 PACS Instrument Overview2 Instrument Concept Imaging photometry –two bands simultaneously (60-85 or 85-130 µm and 130-210 µm) with dichroic beam splitter –two filled bolometer arrays (32x16 and 64x32 pixels, full beam sampling) –point source detection limit ~3 mJy (5 , 1h) Integral field line spectroscopy –range 57 - 210 µm with 5x5 pixels, image slicer, and long-slit grating spectrograph (R ~ 1500) –two 16x25 Ge:Ga photoconductor arrays (stressed/unstressed) –point source detection limit 2…8 x10 -18 W/m 2 (5 , 1h) Focal Plane Footprint 32 x 16 pixels 6.4” x 6.4” 64 x 32 pixels 3.2” x 3.2”

3. PACS IBDR 27/28 Feb 2002 PACS Instrument Overview3 Observing Modes Combinations of instrument modes and satellite pointing modes Instrument modes: –dual-band photometry –single-band photometry –line spectroscopy observation of individual lines –range spectroscopy observation of extended wavelength ranges Pointing modes: –stare/raster/line scan –with/without nodding

4. PACS IBDR 27/28 Feb 2002 PACS Instrument Overview4 CEA BOL/BAU BlueBol BAU RedBol BAU Warm Interconnecting Harness Instrument Overview and Subsystem Responsibilities DPU nominal DPU redundant IFSI-ROME DEC/MEC 2 MEC I/F-Module Redundant DSP Module Redundant RedDEC Module Base/PSU Redundant CSL-Liege BOL/COOL BOL 1 Module BOL 2 Module Cooler Control CEA FPU Cold FocalPlaneUnit KT/MPE BlueGe:GaArray &CRE MPE/ANTEC/IMEC BlueBolArray &Read-out CEA RedBolArray &Read-out CEA RedGe:GaArray &CRE MPE/ANTEC/IMEC 0.3K Cooler CEA Grating Assy CSL-Liege Chopper Assy MPIA 2FilterWheels KT 2BlackBodies KT SPU nominal SPU redundant IAC-Tenerife/TU-Wien CSL-Liege DEC/MEC 1 MEC I/F-Module DSP Module BlueDEC Module Base/PSU

5. PACS IBDR 27/28 Feb 2002 PACS Instrument Overview5 DPU Single point of communication with satellite TC/TM –reception and execution or distribution of commands –transfer of science and HK data –autonomy functions

6. PACS IBDR 27/28 Feb 2002 PACS Instrument Overview6 SPU Data compression –lossy part (average / fit) –lossless part (redundancy removal) Must reduce raw data rate from up to 3.6 Mbit/s to ~120 kbit/s

7. PACS IBDR 27/28 Feb 2002 PACS Instrument Overview7 DECMEC Photoconductor operation and readout –CRE supply and timing/control –detector bias –signal acquisition FPU mechanisms control/ synchronization –chopper –filter wheels –grating BOLC data acquisition and control Communication with SPU and DPU

8. PACS IBDR 27/28 Feb 2002 PACS Instrument Overview8 BOLA / BOLC BOLA 160-channel JFET buffer at ~100 K BOLC Acquisition of signals from 160 multiplexers in bolometer arrays Sequencer for bolometer operation / readout Control of 300 mK cooler Transfer of digitized data to DECMEC

9. PACS IBDR 27/28 Feb 2002 PACS Instrument Overview9 FPU/Optics FPU Cold FocalPlaneUnit KT/MPE BlueGe:GaArray &CRE MPE/ANTEC/IMEC BlueBolArray &Read-out CEA RedBolArray &Read-out CEA RedGe:GaArray &CRE MPE/ANTEC/IMEC 0.3K Cooler CEA Grating Assy CSL-Liege Chopper Assy MPIA 2 FilterWheels KT 2 Calibrators KT Chopper sGeGaDetector Red Spectrometer Blue Bolometer Red Bolometer Calibrator I and II 0.3 K Cooler Filter Wheel I Filter Wheel II Grating GeGa Detector Blue Spectrometer Encoder Grating Drive Entrance Optics Photometer Optics Calibrator Optics Slicer Optics Spectrometer Optics

10. PACS IBDR 27/28 Feb 2002 PACS Instrument Overview10 Design/Development Status of Technically Critical Components Optics FPU/Structure Photoconductors, CRE Bolometers Chopper Grating assembly Warm electronics

11. PACS IBDR 27/28 Feb 2002 PACS Instrument Overview11 Optics Design of FPU optics complete, manufacturing of mirror blanks started Alignment plan exists; tolerancing partly done Analyses (geometrical-optical, diffraction) done end- to-end for selected cases; coverage of parameter space (wavelength, chopper angle) to be improved in context of instrument calibration Baffle design of FPU nearly finished; straylight analysis difficult Calibration sources conceptual design achieved  Details from N. Geis

12. PACS IBDR 27/28 Feb 2002 PACS Instrument Overview12 Detailed design of FPU structure in final phase. Structural problems solved. First part (“top optics”) in manufacturing. Delay for manufacturing from some interface problems and from late input –bolometer unit mounting interface –electrical distribution board design –detector array cable harness –filter mounts  Details from J. Schubert and D. Kampf FPU Status

13. PACS IBDR 27/28 Feb 2002 PACS Instrument Overview13

14. PACS IBDR 27/28 Feb 2002 PACS Instrument Overview14 Environmental testing successful Performance tests on both high and low-stress modules with TIA: QE looks ok (high-stress: >30%) Design Changes –short-circuit “immunity” implemented in FM design Manufacturing Status –QM completed – but FEE integration outstanding –FM in production Problems –“pigtail” harness late and hard to fit in FPU –late readiness of FEEs  Details from H. Richter and D. Rosenthal Photoconductor Arrays

15. PACS IBDR 27/28 Feb 2002 PACS Instrument Overview15 Cryogenic Read-Out Electronics CREs have undergone complete redesign over the last two years Progress with new design from both, optimization of transistor geometry and of circuit design CQM run ‘032001’ –design/layout improvement and local optimization of input stage –successfully tested by IMEC and by CSL, working at MPE –will be used for detector module tests at LENS CQM run ‘102001’ –essentially integrator type _024 (as 032001) –evolutionary combination of additional features (4 C int, increased dynamic range) –for integration into QM detector modules, dice delivery 11/2001  Details from C. van Hoof

16. PACS IBDR 27/28 Feb 2002 PACS Instrument Overview16 CRE032001 Performance Linearity : 2V Cross talk between channels: <1% full range Noise, linearity, cross talk ~ meet requirements Tests of CREs with detectors still ahead (early ’02) 16

17. PACS IBDR 27/28 Feb 2002 PACS Instrument Overview17 Bolometer Arrays Two complete “blue” arrays mounted in cryostat at LETI for optical characterization Red arrays being assembled Cold multiplexer/buffer noise (differential mode) < 1 µV/Hz 1/2 Detection efficiency 80% (calculated) across PACS spectral bands Good tolerance to uncertainty in background level shown by modeling  Details from L. Rodriguez

18. PACS IBDR 27/28 Feb 2002 PACS Instrument Overview18 3 He Sorption Cooler 300 mK cooler development on track, good margin for 46h operation  Details from L. Duband

19. PACS IBDR 27/28 Feb 2002 PACS Instrument Overview19 Chopper Status QM –Manufacturing at MPIA started mid Oct 2001 –Qualification tests started January 2002 –Delivery to MPIA/MPE/KT planned for March 2002, but delayed due to pigtail delivery Problems –Damage of flex pivots in lifetime model operation  Details from R. Hofferbert

20. PACS IBDR 27/28 Feb 2002 PACS Instrument Overview20 Grating Diffraction GratingSample received from Zumtobel GmbH (A), under evaluation Zeiss for FM manufacture as backup Actuatorordered from TU Berlin after successful performance test at 4K Position Sensorordered from FARRAND after successful breadboard test of sensor at 4K Bearingscoatings and preload control under evaluation Launch-lockprototype under fabrication  More information from E. Renotte

21. PACS IBDR 27/28 Feb 2002 PACS Instrument Overview21 Warm Electronics Development BOLA –Mechanical design updated –Box thermal behavior modeling in progress –JFET modeling for effect of temperature on performance in progress BOLC –Mechanical design BOLC updated (2 stacked boxes) –Analogue board prototype ready for performance test –Bolometer bias board (QM1) ready for design –“300mK” temperature control prototype designed –FPGA implementation of IEEE1355 under test at CSL –Most digital functions designed, except bolometer sequencer

22. PACS IBDR 27/28 Feb 2002 PACS Instrument Overview22 Warm Electronics Development DEC/MEC –DEC/MEC AVM Status DSP and DEC simulator available / development on schedule –DEC/MEC EM Status design and procurement ongoing, but validation with representative hardware pending on mechanism simulators availability from partners –DEC/MEC On-board Software Status sequencer complete communication 70% tested mechanism control low-level S/W ~ 0% MEC-to-DPU simulator completed: Virtuoso + OBS emulated on a PC –Successful operation of CRE with DEC prototype low noise + good linearity CRE 03/01 @ 4K

23. PACS IBDR 27/28 Feb 2002 PACS Instrument Overview23 Instrument Performance Instrument Requirements –Photometer –Spectrometer Instrument Model –Optical performance –Sensitivity budget optical transmission background detector performance

24. PACS IBDR 27/28 Feb 2002 PACS Instrument Overview24 Photometer Performance Requirements Image quality –blur: telescope limited –distortion: ±1 pixel; alignment: <1/3 pixel Sensitivity (point source detection) –requirement: 5 mJy (5  ), 1h of integration –goal: 3 mJy (5  ), 1h of integration Dynamic range –detection from 3 mJy to >1000 Jy (goal: 3000 Jy) –contrast of up to 1:500 in one field Post-detection bandwidth –requirement: 0.5 - 5 Hz –goal: 0.05 - 5 Hz

25. PACS IBDR 27/28 Feb 2002 PACS Instrument Overview25 Spectrometer Performance Requirements Image quality –blur: telescope limited –distortion: ±1 pixel; alignment: <1/4 pixel Sensitivity (point source detection) –requirement: 3x10 -18 W/Hz 1/2 (5  ), 1h of integration –goal: 2x10 -18 W/Hz 1/2 (5  ), 1h of integration Dynamic range –detection from ~1x10 -18 W to >10 -13 W –contrast of up to 1:100 in one field Post-detection bandwidth –requirement: 5 Hz –goal: 10 Hz

26. PACS IBDR 27/28 Feb 2002 PACS Instrument Overview26 Optical Performance Optical design fulfills requirements regarding –field of view –spatial sampling –distortion –geometrical spot sizes (Strehl ratio) –alignment –internal calibration capability –chopping –spectral coverage and resolution –transmission / diffraction losses  Details from N. Geis

27. PACS IBDR 27/28 Feb 2002 PACS Instrument Overview27 (a) Values for the photometry modes from 60-85 or 85-130 µm / 130-210 µm, respectively. (b) The formal transmission of >1 takes into account the acceptance solid angle of the photoconductor light cones / bolometer baffles which differs from the beam solid angle. Parameters of PACS Instrument Model (Present Best Estimate)

28. PACS IBDR 27/28 Feb 2002 PACS Instrument Overview28 Background, NEP, Spectroscopic and Photometric Sensitivity  Performance requirements (or even goals) can be met assumed detector QEs: 30% (spectroscopy); 80% (photometry) assumed detector NEPs: 5x10 -18 W/Hz 1/2 (spectroscopy); 10 -16 W/Hz 1/2 (photometry)