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PACS CQM/AVM ILT

PACS CQM/AVM ILT. Results of functional/performance/ calibration tests. Major (science) requirements on PACS. Detectors: Sensitivity, Detector/readout noise (NEP), Dynamic Range Image Quality: blur, distortion, misalignment

hermione-woodard
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PACS CQM/AVM ILT

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  1. PACS CQM/AVM ILT Results of functional/performance/ calibration tests AVM/CQM ILT – test results

  2. Major (science) requirements on PACS Detectors: Sensitivity, Detector/readout noise (NEP), Dynamic Range Image Quality: blur, distortion, misalignment Spectral resolution, wavelength range, filter bands, photometric accuracy, .... Chopper: frequency, duty cycle, stability on plateau, position accuracy, range (throw) Calibration Sources: time constants, stability, emissivity Stray Light: homogeneous, inhomogeneous See PACS Science Requirement Document PACS Instrument Requirement Document More PACS Sub-unit specifications and requirements documents... AVM/CQM ILT – test results

  3. Two cryogenic test phases (19-23 July, 6 Sep-29 Oct) • Functional and Performance tests of all mechanisms, detectors, array read-outs, sensors and sources (Test/Analysis Reports), including Test Optics • Calibration tests ( calibration files, reports) • S/W tests and improvements (QLA, TA, IA, e.g. visualization, detector sorting, de-compression) • Tests/debugging of warm electronics (e.g. DEC/MEC) • Tests of command scripts (Tcl, CUS), On-Board Control Procedures (OBCPs), Astronomical Observation Templates (AOT) AVM/CQM ILT – test results

  4. LB LB LB LB LB LB LB LB LB LB AVM/CQM ILT – test results

  5. AVM/CQM ILT – test results

  6. I) S/W and Warm Electronics AVM/CQM ILT – test results

  7. Detector Sorting Bolometer (IA Display Tool) • Bolc Simulator Test Pattern • reconstructed • Figure by IA Display tool Bolometer Blue Bolometer Red AVM/CQM ILT – test results

  8. Detector Sorting Spectrometer AVM/CQM ILT – test results

  9. Detector Sorting Spectrometer (Status Ge:Ga arrays pixel performance (SCOS result)) AVM/CQM ILT – test results

  10. Detector Sorting Spectrometer (Status Ge:Ga arrays pixel performance (SCOS result)) AVM/CQM ILT – test results

  11. PACS - QLA AVM/CQM ILT – test results

  12. IA Plot / Display • Setting & saving Plot settings • Labels, Axis, zooming, hardcopy, • plotsymbols, ... • Plot to PS without rendering • Well documented AVM/CQM ILT – test results

  13. II) Functional/Performance tests and instrument characterisation AVM/CQM ILT – test results

  14. AVM/CQM ILT – test results

  15. AVM/CQM ILT – test results

  16. AVM/CQM ILT – test results

  17. Cross-reference: major (science) requirements on PACS vs. PCD Detectors: Sensitivity 3.2.1, 3.2.6, 4.3.8 Detector/readout noise (NEP) 1.1.11, 1.1.12, 1.2.10 Dynamic range 1.2.3, 4.3.6 Image Quality: blur, distortion, misalignment, PSF, ... 3.1.2, 3.1.3, 3.1.4, 4.1.1, 4.1.2, 4.1.3 Spectral resolution 4.2.2 Chopper: frequency, duty cycle, stability on plateau, position accuracy, range (throw) 0.7.5, 0.7.6, 0.7.13, 2.3.2 Calibration Sources: time constants, stability, emissivity 0.7.11, 0.7.12 Stray Light, ghosts: 3.1.5, 3.1.6, 4.2.4 AVM/CQM ILT – test results

  18. II A) Photometer functional tests and characterisation AVM/CQM ILT – test results

  19. Performed tests (photometer) - 0.7.1 FPU thermal behaviour (photometer) - 0.7.2 Test of cooler recycling and operation - 0.7.4 Verify function of bolometer detectors - 0.7.5/6 and 2.3.2 Verify function of PACS chopper / performance test / duty cycle - 0.7.7 Verify function of photometer filter wheels - 0.7.11/12 Verify function of internal calibration sources / performance test - 1.1.1 Control optimum pixel bias setting - 1.1.10 Measure time constants after a flux change - 1.1.11 Measure the low frequency noise - 1.1.12 Measure the bolometer Noise Equivalent Power (NEP) AVM/CQM ILT – test results

  20. - 2.2.3 Optimum positioning of chopper on internal reference sources (bolometer) • - 2.5.1 Temporal stability of internal calibration sources • - 2.5.3/0.7.12 Time constants: heat-up & cool-down times of internal calibration sources • 3.1.1 Central pointing position (photometer) • 3.1.2 Relation between chopper position and angular displacement on sky • 3.1.4 Photometer Point Spread Function (PSF) • 5.1.1 OBCP and AOT tests • many ad hoc tests (including tests of test equipment/test optics) • Conclusion: Tests were often hampered by DECMEC problems. Bolometer sufficiently tested for CQM ILT purposes AVM/CQM ILT – test results

  21. Example 1 - Chopper FT, duty cycle • Analysis of the waveform of the chopper modulation for different chopping frequencies and chopper deflections both for rectangular (two-position) and triangular (three-position) chopping. • Duty cycle requirements: • On sky: >80% for 0-10 Hz chopping frequency • On Cal. Sources: > 70% (larger throw) AVM/CQM ILT – test results

  22. Actual chopper position vs. Time (here: 0.8 Hz, ±1.2 degrees) Fluctuations well within spec AVM/CQM ILT – test results

  23. Mean duty cycle for different chopping frequencies vs. chopping throw Here: square modulation AVM/CQM ILT – test results

  24. Comparison to measure- ments of Zeiss Compared to CQM measure- ments shorter swinging-in phase with smaller amplitude. Plateaux much smoother. Requirements fulfilled for all frequencies and deflections.  poorly adjusted DEC/MEC control parameters ? AVM/CQM ILT – test results

  25. Example 2 – PACS Calibration Sources Analysis of the time constants and stability of the two internal calibration sources. AVM/CQM ILT – test results

  26. Heat-up and temperature plateau behaviour (after DECMEC adjustments) AVM/CQM ILT – test results

  27. Emissivity of calibration sources measured against OGSE cryogenic blackbody. Values close to design value. AVM/CQM ILT – test results

  28. Example 3 – Bolometer flat field and offset Discarded pixels Module 5 Module 1 Module 2 Image of the offset Image of the flat-field (gain) p=chopper position T=temperature s(i, j, p, T) = o(i, j) + g(i, j) × f(i, j, p, T) measured signal input signal AVM/CQM ILT – test results

  29. Example 4 – Photometer Field of View Chopper Step-Scan Across PACS FOV • “Astronomical” field = cold OGSE BB • Internal calibrators set to 70 K (left) and 90 K (right) • No flatfielding applied AVM/CQM ILT – test results

  30. Example 4 - Chopper Step-Scan Across PACS FOV AVM/CQM ILT – test results

  31. OGSE BB1 OGSE BB2 Chopper position AVM/CQM ILT – test results

  32. dead/bad subarrays Example 5 - First Point Source Image (Blue Photometer) • “Point source”: hole with equiv. diam. 7” (~2 pixels) in front of external blackbody • Blue photometer, on-array chopping + nodding to remove very uneven OGSE background, no flat-field • “Point source”: hole with equiv. diam. 7” (~2 pixels) in front of external blackbody, on-array chopping+nodding • Same source, “line scanning” mode, unprocessed data • “Point source”: hole with equiv. diam. 7” (~2 pixels) in front of external blackbody, on-array chopping+nodding + beam - beam AVM/CQM ILT – test results

  33. PSF wider than expected (25-50%). This discrepancy clealy needs investigation. Part (most?) of it may be due to the imperfect focus of the PACS/OGSE setup and to the non-nominal plate scale. • Strehl ratio can not be determined reliably right now. Sigma of a 2D gaussian fit to the PSF of measured and simulated data AVM/CQM ILT – test results

  34. Summary of preliminary analysis: • OGSE external focus off the design position • PSF wider than expected (25-50%) • Misalignments (1-4 degrees) between XY stage, chopper, arrays and subarrays • Plate scale of the OGSE/PACS setup (mm on XY stage vs. pixels on detector array) is 10% off the design value. Assumed explanation: caused by de-focus. • Several of these results imply modifications of OGSE setup, test procedure and/or planning of FM tests. But there are no implications for CQM IST at this point. AVM/CQM ILT – test results

  35. Example 6 – Time constants after switch-on OGSE BB1 (29K) and 2 (6.5K), OGSE chopper wheel at 500mHz AVM/CQM ILT – test results

  36. Example 6 – Time constants after switch-on • Bolometer signal roughly stabilized within 2 hours after the switch-on • Implications for observing strategy will be discussed at AOT workshop AVM/CQM ILT – test results

  37. 1/f knee ~0.125 Hz Noise density 5 µV/Hz1/2 Example 7 – Bolometer Responsivity, Noise Spectrum, NEP Responsivityon OGSE BBs 1 x 1010 V/W NEP = 5 x 10-16 W/Hz1/2,as measured at subunitlevel tests AVM/CQM ILT – test results

  38. Example 7 – Bolometer Responsivity, Noise Spectrum, NEP AVM/CQM ILT – test results

  39. II B) Spectrometer functional tests and characterisation AVM/CQM ILT – test results

  40. Performed tests (spectrometer) - 0.7.1 FPU thermal behaviour (spectrometer) - 0.7.3 Verify function of Ge:Ga detectors, CREs, detector heaters and related temperature sensors; many CRE tests for testing of compression/de-compression, DECMEC etc. - 0.7.5/6 Verify function of PACS chopper (spectrometer), performance test - 0.7.7 Verify function of spectrometer filter wheels - 0.7.8 Verify function of grating - 0.7.11/12 Verify function of internal calibration sources / performance test - 1.2.1 Optimum detector bias settings - 1.2.3 Dynamic range per selected integration capacitor - 1.2.4 CRE check-out voltage - 1.2.6 Detector dark current - 1.2.11 Linearity of CRE readout - 2.3.2 Duty cycle of chopper waveforms AVM/CQM ILT – test results

  41. - 2.3.3 Optimum positioning of chopper on internal reference sources (spectrometer) - 2.5.2 Spatial stability of internal calibration sources - 4.1.1 Spectrometer central pointing position and grating alignment - 4.1.3 Spectrometer PSF - 4.2.1 Grating wavelength calibration - 4.3.2 Flux reproducibility internal sources - 4.3.4 Flux reproducibility external sources - 4.3.5 Linearity with flux - 4.3.8 Relative Spectral Response Function spectrometer - 5.2.1/2 OBCP tests, calibration AOT - Spectral map focal plane - Attempts with external laser - many ad hoc tests (in particular to debug DECMEC, CRE tests) Conclusion: Tests were often hampered by DECMEC problems (including CRE settings) and by spectrometer filter wheel being stuck. AVM/CQM ILT – test results

  42. Example 8 – grating drive performance Oscillations within specs AVM/CQM ILT – test results

  43. Example 9 – grating wavelength calibration Against water vapor absorption spectrum, Input source: external BB, 25.4mm, T=730C, absorption path in air: ~20 cm AVM/CQM ILT – test results

  44. Example 9 – grating wavelength calibration AVM/CQM ILT – test results

  45. Example 9 – grating wavelength calibration The S/N on quite a number of pixels and a number of lines has been very poor, such that substructure in the continuum may cause apparent shifts of the measured peak positions. Strongly fringed pixels in the red section have not been used in this analysis. The accuracy of the reference water spectrum is limited, air temperature and pressure have not been monitored and no other air species than H2O have been included in the calculations. Some small systematic offsets for blended water lines may therefore be present in the reference list. Given these problems, no attempt has been made to improve further on the calibration accuracy, by fitting correction polynomials to individual modules/pixels. The present accuracy for the red spectrometer is of the order of a resolution element while for the blue section it is better, more of the order half to a third of a spectral resolution element. AVM/CQM ILT – test results

  46. Example 10 – Fringes AVM/CQM ILT – test results

  47. Example 11 – Spectral resolution and Instrumental Profile AVM/CQM ILT – test results

  48. Example 12 – Spectral Leakage and Ghosts 3rd order leaking into 2nd order (blue filter cut-off) 2nd order leaking into 1st order (dichroic cut-off), plus 0th order ? Strong narrow features beyond band limit (?) AVM/CQM ILT – test results

  49. Example 12 – Spectral Leakage and Ghosts Angular dependent filter transmission (?) Multiple reflections of 2nd order leaking into 1st order (?) AVM/CQM ILT – test results

  50. Example 13 – grating health checks/change in behaviour Hall sensors vs. Grating position over time Spectrum vs. Grating position over time (This occured after DECMEC malfunction had driven grating against hard stop at full speed) AVM/CQM ILT – test results

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