PACS IQR 13 Jan 2005 AVM/CQM ILT – test results1 PACS CQM/AVM ILT Results of functional/performance/ calibration tests

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results2 Major (science) requirements on PACS Detectors: Sensitivity Detector/readout noise (NEP) Dynamic Range Chopper: Stray Light: Image Quality: Spectroscopy Photometry Few x W/m 2 (5σ, 1hr) 5 x W/Hz 1/2 Few mJy (5σ, 1hr) 1 x W/Hz 1/ Jy Jy

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results3 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...

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results4

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results5 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)

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results6 LB

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results7

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results8 I) S/W and Warm Electronics

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results9 Detector Sorting Bolometer (IA Display Tool) - Bolc Simulator Test Pattern reconstructed - Figure by IA Display tool Bolometer Red Bolometer Blue

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results10 Detector Sorting Spectrometer

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results11 Detector Sorting Spectrometer (Status Ge:Ga arrays pixel performance (SCOS result))

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results12 Detector Sorting Spectrometer (Status Ge:Ga arrays pixel performance (SCOS result))

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results13 PACS - QLA

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results14 IA Plot / Display - Setting & saving Plot settings - Labels, Axis, zooming, hardcopy, plotsymbols,... - Plot to PS without rendering - Well documented

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results15 II) Functional/Performance tests and instrument characterisation

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results16

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results17

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results18

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results19 Cross-reference: major (science) requirements on PACS vs. PCD Detectors: Sensitivity3.2.1, 3.2.6, Detector/readout noise (NEP)1.1.11, , Dynamic range 1.2.3, Image Quality: blur, distortion, misalignment, PSF, , 3.1.3, 3.1.4, 4.1.1, 4.1.2, Spectral resolution Chopper: frequency, duty cycle, stability on plateau, position accuracy, range (throw) 0.7.5, 0.7.6, , Calibration Sources: time constants, stability, emissivity , Stray Light, ghosts: 3.1.5, 3.1.6, 4.2.4

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results20 II A) Photometer functional tests and characterisation

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results21 Performed tests (photometer) FPU thermal behaviour (photometer) Test of cooler recycling and operation Verify function of bolometer detectors /6 and Verify function of PACS chopper / performance test / duty cycle Verify function of photometer filter wheels /12 Verify function of internal calibration sources / performance test Control optimum pixel bias setting Measure time constants after a flux change Measure the low frequency noise Measure the bolometer Noise Equivalent Power (NEP)

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results Optimum positioning of chopper on internal reference sources (bolometer) Temporal stability of internal calibration sources / Time constants: heat-up & cool-down times of internal calibration sources Central pointing position (photometer) Relation between chopper position and angular displacement on sky Photometer Point Spread Function (PSF) 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

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results23 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)

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results24 Commanded vs. actual (read-back) chopper position against time

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results25 Actual chopper position vs. Time (here: 0.8 Hz, ±1.2 degrees) Fluctuations well within spec

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results26 Mean duty cycle for different chopping frequencies vs. chopping throw Here: square modulation

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results27 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 ?

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results28 Example 2 – PACS Calibration Sources Analysis of the time constants and stability of the two internal calibration sources.

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results29 Heat-up and temperature plateau behaviour (after DECMEC adjustments)

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results30 Emissivity of calibration sources measured against OGSE cryogenic blackbody. Values close to design value.

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results31 Emissivity of calibration sources measured against OGSE cryogenic blackbody. Values close to design value.

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results32 Example 3 – Bolometer flat field and offset s(i, j, p, T) = o(i, j) + g(i, j) × f(i, j, p, T) Image of the offsetImage of the flat-field (gain) measured signalinput signal p=chopper position T=temperature Module 5 Module 1Module 2 Discarded pixels

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results33 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

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results34 Example 4 - Chopper Step-Scan Across PACS FOV

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results35 OGSE BB1 OGSE BB2 Chopper position

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results36 “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 Example 5 - First Point Source Image (Blue Photometer) dead/bad subarrays + beam - beam “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

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results37 Sigma of a 2D gaussian fit to the PSF of measured and simulated data  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.

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results38 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.

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results39 Example 6 – Time constants after switch-on OGSE BB1 (29K) and 2 (6.5K), OGSE chopper wheel at 500mHz

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results40 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

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results41 Example 7 – Bolometer Responsivity, Noise Spectrum, NEP Responsivity on OGSE BBs 1 x V/W 1/f knee ~0.125 Hz Noise density 5 µV/Hz 1/2 NEP = 5 x W/Hz 1/2, as measured at subunit level tests

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results42 Example 7 – Bolometer Responsivity, Noise Spectrum, NEP

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results43 II B) Spectrometer functional tests and characterisation

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results44 Performed tests (spectrometer) FPU thermal behaviour (spectrometer) Verify function of Ge:Ga detectors, CREs, detector heaters and related temperature sensors; many CRE tests for testing of compression/de-compression, DECMEC etc /6 Verify function of PACS chopper (spectrometer), performance test Verify function of spectrometer filter wheels Verify function of grating /12 Verify function of internal calibration sources / performance test Optimum detector bias settings Dynamic range per selected integration capacitor CRE check-out voltage Detector dark current Linearity of CRE readout Duty cycle of chopper waveforms

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results Optimum positioning of chopper on internal reference sources (spectrometer) Spatial stability of internal calibration sources Spectrometer central pointing position and grating alignment Spectrometer PSF Grating wavelength calibration Flux reproducibility internal sources Flux reproducibility external sources Linearity with flux Relative Spectral Response Function spectrometer /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.

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results46 Example 8 – grating drive performance Oscillations within specs

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results47 Example 9 – grating wavelength calibration Against water vapor absorption spectrum, Input source: external BB, 25.4mm, T=730C, absorption path in air: ~20 cm

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results48 Example 9 – grating wavelength calibration

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results49 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 H 2 O 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.

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results50 Example 10 – Fringes

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results51 Example 11 – Spectral resolution and Instrumental Profile

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results52 Example 12 – Spectral Leakage and Ghosts 2nd order leaking into 1st order (dichroic cut- off), plus 0th order ? 3rd order leaking into 2nd order (blue filter cut-off) Strong narrow features beyond band limit (?)

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results53 Example 12 – Spectral Leakage and Ghosts Multiple reflections of 2nd order leaking into 1st order (?) Angular dependent filter transmission (?)

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results54 Example 7 – grating scans/stray light

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results55 Example 13 – grating health checks/change in behaviour Hall sensors vs. Grating position over timeSpectrum vs. Grating position over time (This occured after DECMEC malfunction had driven grating against hard stop at full speed)

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results56 Look out of the cryostat window toward Hg arc lamp through lab air Internal blackbody for reference Example 9 - First (Water) Spectra (Spectrometer)

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results57 “Point source”: hole with equiv. diam. 7” (~1 pixel) in front of external blackbody Blue spectrometer, (source on) – (source off) (averaged over the 16 spectral channels of each spatial pixel) Good agreement with predicted PSF Example 14 - First Point Source Image (Spectrometer)

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results58 Example 15 – Linearity of CRE read-out Analysis of the linearity of the integration ramps of the illuminated detector pixels of the red and blue spectrometer array. The required accuracy is less than 3% deviation from a first order fit The chopper position for all files was at ADcounts (-10 degrees) which is outside the science and even calibration window. Consequently, the detectors detected not the OGSE black body radiation but only stray light! Measurements still usefull (e.g. linearity, stability of ramp slope, etc.), but no trend with temperature measurable.

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results59 Example 15 – Linearity of CRE read-out The non-linearities decrease significantly, the hook in the beginning of the ramp is almost gone and the oscillation behaviour is strongly reduced. This indicates that a correlated disturbing signal is modulated on the ramps of all pixels of a module. Open channel subtracted 8Hz oscillations

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results60 Example 15 – Linearity of CRE read-out - Different commanded OGSE black body temperature values do not affect the slopes of the ramps. This seems to be caused by a chopper position outside the measuring windows at which the detectors only see stray light. - The ramps exhibit a starting hook and superimposed oscillations mainly at a frequency of 8 Hz and harmonics. The subtraction of the open channel output decreases these effects substantially and leads to a ramp almost perfectly linear. - The responsivity variations of the pixels within a module slightly exceed the requirement specifications of 30%. (Could be inhomogenous illumination, though) - The stability of the output signal shows a range of 8 to 35% and is consequently far beyond the requirement specification of 1%. - The current noise density is around 8 × 10 −15 AHz −1/2 and exceeds the requirement specification of 7 × 10 −17 AHz −1/2 by a factor of about 100 (but unsure due to the unknown voltage range corresponding to the ADC range). - The non-linearity of the ramps is about 10%. Consequently, the requirement specification of 3% is not fulfilled. This high non-linearity is mainly caused by the first max. 13 ramp read-outs (starting hook). This analysis should be repeated using ramps with a higher dynamic range and a better number statistics.

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results61 Example 16 – Signal/Noise Measurements (Red Module, QM5) Measurement in detector test cryostat (MPE electronics) Measurement in PACS (DECMEC) S/N ratio as measured during module tests re-established during ILT with full signal/data chain

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results62 Example 16 – Signal/Noise Measurements (Blue Module) Measurement in PACS (DECMEC) (FM42) Measurement in detector test cryostat (MPE electronics)

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results63 Example 17 – Dark Current

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results64 Example 17 – Dark Current Dark current determination (preliminary!) Dark current of I dark,195 = 4.3 · 10 −14 A or e−/s. This would be a factor of 5.4 above the specs. The signals refer, however, to the CFOV measurement, which might not be completely dark, so that the derived value must be considered as an upper limit. Comparison with results from module level tests (preliminary!) Dark current measurements of unstressed detector arrays carried out at MPIA yielded dark currents between 1 and 3 · 10 −13 A for the temperature range 1.7 to 2.9K. The derived dark current for pixel ID 195 (which is a high stressed pixel) is a factor of 2.3 smaller than the lowest values found for the blue (unstressed) detector modules on module level.

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results65 Example 17 – Optimum Detector Bias The purpose of these calibration test (1.2.1 and 1.2.2) is to find the optimum bias voltage and temperature range where the detector operates under stable conditions and the NEP shows a minimum. During CQM tests the heater on the blue detector array housing was not functional, therefore the detectors were kept at FPU temperature without active regulation. The optimisation procedure under these circumstances was restricted to a bias scan at constant FPU temperature. In this DRAFT version no NEP was calculated but σ(s i /|median(s)|) was derived instead, where s i represents the the individual slopes on subramps and |median(s)| is the absolute value of slopes median. This measure is proportional to the NEP, the derived minima will not change when switching to NEP.

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results66 Example 17 – Optimum Detector Bias The mean value in the red is ~75 mV. The mean value in the blue is ~200 mV. bluered Preliminary!

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results67 III) OBCPs, AOT definition

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results68 At present the following Observing modes are offered by PACS: -Line Spectroscopy -Range Spectroscopy -Dual band photometry -Single band photometry (basically as fall back or for parallel mode with SPIRE) They will be commanded via On-Board Command Procedures (OBCPs), e.g. -OBCP8: Grating Line scan with 2 or 3 position chopping -OBCP5: Photometry with 2 or 3 position chopping with dither -OBCP 10: Internal calibration I

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results69 Each AOT consists in principle of: -AOT specific setup -OBCP -Change_Setup -OBCP -Change_Setup -OBCP Change_Setup -OBCP -AOT specific reset

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results70 - One example for an AOT (chopped photometry) was already implemented as CUS script (incl. OBSID and BBID). - OBCPs (the AOT building blocks) and dedicated AOT tests were performed in ILT. - A (2-day) workshop is planned (17-18 January 2005) to discuss further strategies for the (intimately linked) issues of AOT design, calibration files, and data analysis - Next Milestones: - End 2004: Proof of concept - Mid 2005: Deliver parameter sets/AOT definitions and observing time calculator End 2005: update calibration files (e.g. sensitivities) for time calculator

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results71 - One example for an AOT (chopped photometry) was already implemented as CUS script (incl. OBSID and BBID). - OBCPs (the AOT building blocks) and dedicated AOT tests were performed in ILT. - Map making strategies (e.g. scanning vs. rastering) are currently analyzed at NHSC, using the PACS Observation Simulator (performance problems need to be overcome) - A (2 day) workshop is planned (17-18 January 2005) to discuss further strategies for the (intimately linked) issues of AOT design, calibration files, and data analysis - Next Milestones: - End 2004: Deliver observing time calculator for all PACS AOTs

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results72 HSPOT communicates with the CUS Engine. All parameters are passed from HSPOT to the CUS Engine. Any calculations are done in the CUS Engine, because all logic is contained in the CUS script. PACS will not provide a stand-alone time calculator but a first version of the AOT logic. The AOT logic is implemented in CUS scripts. AOT execution times will be calculated there. In addition to the time calculator the CUS engine will also contain a noise estimator (based for now on theoretical expectations).

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results73 Cross-reference: major (science) requirements on PACS vs. PCD Detectors: Sensitivity3.2.1, 3.2.6, Detector/readout noise (NEP)1.1.11, , Dynamic range 1.2.3, Image Quality: blur, distortion, misalignment, PSF, , 3.1.3, 3.1.4, 4.1.1, 4.1.2, Spectral resolution Chopper: frequency, duty cycle, stability on plateau, position accuracy, range (throw) 0.7.5, 0.7.6, , Calibration Sources: time constants, stability, emissivity , Stray Light, ghosts: 3.1.5, 3.1.6, 4.2.4

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results74 III) EMC Tests

PACS IQR 13 Jan 2005 AVM/CQM ILT – test results75 Example 19 – RS - H Field, Red and Blue Bolometers