PACS SVR 2 18 Jan 2007 FM ILT: Mechanisms1 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

1

FM ILT Results: Mechanisms

H. Feuchtgruber, H. Dannerbauer, N. Geis, C. Hartinger, U. Klaas,

P. Royer

FM ILT: Mechanisms


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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


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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


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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.

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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.

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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

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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)

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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

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Chopper (2)

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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

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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.

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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

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Calibration Sources (3) Time constants - Complete tests not

carried out.


to 70.5(CS1)/76.5(CS2) K

- Measurements are


HK mode

t(70.5K) = 2700sec

t(76.5K) = 3100sec

Stability in spec.


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- Complete tests not

carried out.


to 70.5(CS1)/76.5(CS2) K

- Measurements are


HK mode

t(70.5K) = 2700sec

t(76.5K) = 3100sec

Time constants

Stability in spec.


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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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blue red

• Short functional tests passed

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Blue @ 0.7mA Red @ 0.4 mA

• Measure a sequence of flasher currents to check illumination pattern (up into saturation)

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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

Documents

PACS SVR 2 18 Jan 2007 FM ILT: Mechanisms1 FM ILT Results: Mechanisms H. Feuchtgruber, H. Dannerbauer, N. Geis, C. Hartinger, U. Klaas, P. Royer