FM ILT: Mechanisms
PACS SVR 2 18 Jan 2007
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FM ILT Results: Mechanisms
H. Feuchtgruber, H. Dannerbauer, N. Geis, C. Hartinger, U. Klaas,
P. Royer
FM ILT: Mechanisms
PACS SVR 2 18 Jan 2007
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Overview of Sub-systems - Grating Launch Lock- Grating Mechanism
- Chopper
- Filter Wheel SPEC- Filter Wheel PHOT
- Calibration Sources CS1, CS2
- Heater Blue and Red- Flasher Blue and Red
FM ILT: Mechanisms
PACS SVR 2 18 Jan 2007
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Test Phases
- Short Functional Tests Warm, LHeI and LHeII
- Mechanism controller parameter optimization
- ILT with blue spectrometer array connected to DMC
- ILT with red spectrometer array connected to DMC
FM ILT: Mechanisms
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Grating Launch Lock Opened during the SFT warm on 12-Oct-06 Closed on 4-Jan-07 (warm)
12-Oct-06
4-Jan-07
FM ILT: Mechanisms
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Grating Mechanism (1) Results - Control loop parameters have been optimized for operation with DMC EQM - Grating health check successfully passed - Accessible range measured - Variety of scans with different step-sizes explored - Duration of step transitions and stability on position is within spec. - We plan to do still better on with the FM DMC and improved OBSW - Grating speed can be set to 4 deg/s as a compromise between small step stability vs. grating speed for large transitions.
FM ILT: Mechanisms
PACS SVR 2 18 Jan 2007
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Grating Mechanism (2) Results - Control loop parameters have been optimized for operation with DMC EQM - Grating health check successfully passed - Accessible range measured - Variety of scans, different stepsizes and speeds explored - Duration of step transitions and stability on position is within spec. - We plan to do still better on with the FM DMC and improved OBSW - Grating speed can be set to 4 deg/s as a compromise between small step stability vs. grating speed for large transitions.
FM ILT: Mechanisms
PACS SVR 2 18 Jan 2007
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Grating Mechanism (3) Results - Control loop parameters have been optimized for operation with DMC EQM - Grating health check successfully passed - Accessible range measured - Variety of scans and different stepsizes explored - Duration of step transitions and stability on position is within spec. - We plan to do still better on with the FM DMC and improved OBSW - Grating speed can be set to 4 deg/s as a compromise between small step stability vs. grating speed for large transitions.
FM ILT: Mechanisms
PACS SVR 2 18 Jan 2007
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Grating Mechanism (4)
PACS-ME-ECR-009: “Expansion of grating angular throw” - CQM: 40.6 degrees; insufficient accessible wavelength range
- FM: accessible range = 44.62 degrees working range = 43.1 degrees (low grating output)
order “measured” specification [45000 – 1050000]
n=3 73.2µm – 34.8 µm 72µm - 56µm n=2 109.8µm – 52.2µm 105µm - 72µm n=1 219.6µm – 104.3µm 210µm - 105µm
FM ILT: Mechanisms
PACS SVR 2 18 Jan 2007
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Grating Mechanism (5)
Problems: - Limit switch at “positive” end is broken (NCR-ME-229) - Non-optimum software handling of grating open loop operation (corrected in latest DMC OBSW) - Grating position information was lost when turning the filter wheel (corrected in latest DMC OBSW, SPR-0651)
FM ILT: Mechanisms
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Chopper (1)
• Duty cycle of chopper has been within specification at sub- system level• Chopper performance is coupled to DMC capabilities• Control loop optimization hasn’t been completed due to NCR-233
Requirements for science operations:deviations from final position < 1’ duty cycle > 80% @10Hz
Requirements for calibration operations:deviations from final position < 2’ duty cycle > 70% @10(5)Hz
FM ILT: Mechanisms
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Chopper (2)
FM ILT: Mechanisms
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Chopper (3)
Science FOV
Measured:- up = 13ms- down = 34ms
Specification:
10ms Need for asymmetry Parameters in control loop identified
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Chopper (4)
Calibration FOV
Measured:- up = 33ms- down = 60ms
Specification:
15(30)ms
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Chopper (5)
• Non-conformance: PACS-ME-NCR-233 Chopper has been de-integrated, further investigations ongoing, replace by original FM chopper • DMC OBSW modifications defined
FM ILT: Mechanisms
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Filter Wheels (1)
Both wheels turned during all test phases, at warm and cold temperatures without any problems.
• Positional reproducibility of FW PHOT is within specification, FW Spec positional accuracy is not yet determined due to bug in commanding script (corrected in the meantime). However there are no indications that it may not be in spec.
FM ILT: Mechanisms
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Filter Wheels (2)
Both wheels turned during all test phases, at warm and cold temperatures without any problems.
• Positional reproducibility of FW PHOT is within specification, FW Spec positional accuracy is not yet determined due to bug in commanding script (corrected in the meantime). However there are no indications that it may not be in spec.
FM ILT: Mechanisms
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Calibration Sources (1)
Time constants
Homogeneity
Emissivity
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Calibration Sources (2) Time constants - Complete tests not
carried out.
- Heat-up from off-state
to 70.5(CS1)/76.5(CS2) K
- Measurements are
done in spectroscopic
HK mode
t(70.5K) = 2700sec
t(76.5K) = 3100sec
• Worse than req. (Stable after ~30min), but only slightly different from CQM
FM ILT: Mechanisms
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Calibration Sources (3) Time constants - Complete tests not
carried out.
- Heat-up from off-state
to 70.5(CS1)/76.5(CS2) K
- Measurements are
done in spectroscopic
HK mode
t(70.5K) = 2700sec
t(76.5K) = 3100sec
Stability in spec.
• Worse than req. (Stable after ~30min), but only slightly different from CQM
FM ILT: Mechanisms
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Calibration Sources (4)
- Complete tests not
carried out.
- Heat-up from off-state
to 70.5(CS1)/76.5(CS2) K
- Measurements are
done in spectroscopic
HK mode
t(70.5K) = 2700sec
t(76.5K) = 3100sec
Time constants
Stability in spec.
• Worse than req. (Stable after ~30min), but only slightly different from CQM
FM ILT: Mechanisms
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Calibration Sources (4)
Homogeneity
CS2CS1
-0,20
-0,19
-0,18
-0,17
-0,16
-0,15
-0,14
-0,13
-0,12- 0,15 - 0,10 - 0,05 0,00 0,05 0,10 0,15
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Calibration Sources (5) Homogeneity: FOV = OGSE BB1 at 22K Significantly improved since CQM, however there is still some small structure on top
CS276.5K
CS170.5K
Straylightissues to be investigated
still !
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Calibration Sources (6) Emissivity CS2 (~76K)
- Measured against cryogenic OGSE blackbody at 30K- Values are within specified range, however change from CQM to FM not effective- The analysis did not yet include straylight effects and accurate temperature derivation for CS2- The OGSE BB was not measured at consistent chopper positions
CQM values for CS2
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Heater Blue & Red
Both heaters passed the functional tests
2 different current settings during SFT warm
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Heater Blue (1)
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Heater Blue (2)
IID-BSpec.
expectedoptimum
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Heater Blue (3)
Detector curing test: Ih=10mA
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Flashers Blue & Red (1)
blue red
blue red
Nylon suspensionsCopper wires
Brass wiresEmitter
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Flashers Blue & Red (2)
blue red
• Short functional tests passed
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Flashers Blue & Red (3)
Blue @ 0.7mA Red @ 0.4 mA
• Measure a sequence of flasher currents to check illumination pattern (up into saturation)
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Flashers Blue & Red (3)
blue red
• Calculated illumination pattern of the arrays (prior to cone)• Including the detector cones results in significantly different “signal pattern” as seen by detector
Peak signalPeak signalShadow by walls
27 46 26 6856 15 35 23 41 4 4026 5 24
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