Overall PACS EQM IMT Analysis Contributions by PACS ICC

Herschel EQM – Results and Lessons Learnt 6/7 Feb 2006

PACS Overall Analysis 1

Overall PACS EQM IMT Analysis

Contributions by PACS ICC



PACS EQM IMT Contents

21-22 Nov 2005

H-Field Tests incl.

threshold measurements

23-25 Nov 2005

E-Field Tests

• Short Functional Test (SFT) warm (3 x) ~ 1h• Short Functional Test (SFT) cold HeII (not done)(~ 1h)

PACS Integrated Module Test:• Full Functional Test (FFT) 7.7h• Short Performance Test (SPT) 12.8h• AOT Test 9.7h• EMC Test (Spec+Phot) ~ 5d

Separate, joint SPIRE/PACS procedure:• PACS/SPIRE Parallel Mode Test (PACS part)~4.7h

• Extra straylight tests (~3d)• Short Functional Test (SFT) cold HeI ~ 1h



Available Reports/Notes • 3 reports on short functional tests warm• 1 report on short functional test HeI

• Performance test of PACS chopper and duty cycle• Internal calibration sources performance tests• Cryostat background adjustment• Emissivity/RSRF on internal calibration sources• Function and performance of PACS grating• Performance test PACS Photometer filter wheel• Ge:Ga detector dark current test on cold internal calibration sources• Ge:Ga bias loop tests and detector performance• Dead/suspicious pixel maps from RSRF, bias loop and dark current tests• Ge:Ga time constants for flux changes • Low frequency noise measurements of the bolometer• Photometer FOV maps

• Summary note on AOT related tests



Warm Electronics and OBSW

• SPU-L failure: loose FPGA removed, repaired and re-installed• DPU AVM1 failure: broken inductor removed and repaired, exchange with CFM2 but that one generated corrupted output only re-installed AVM1 • SPU OBSW: upgraded from V11.1 to 11.7 to prevent IMT data losses due to a known bug, detected during ILT• SPU OBSW: Data rate / CPU workload too high (as expected from ILT) • DPU HW/OBSW: Few known and new bugs detected, but no major show-stopper (Corrupted packet checksums, duplicate HK packets, SSC discontinuities)• BOLC: 20Hz command had unexpected impact on supply groups



Test Results (1)• Chopper

- duty cycle: comparable to ILT (but too small)- noise: slightly worse than in ILT, but still in spec.- Slight angular offset detected: contact with housing has been removed after the ILT



Test Results (2)• Calibration sources

- Nominal performance: total heating time and stability in spec

Fluctuations = 50 unitsSpec.= 7mK = 70 units



Test Results (3)• Grating: Suffered from a DMC FPGA problem (introduced after ILT)

Spontaneous grating controller self-disable

Excessive noise on position readback



Test Results (4)• Photometry Filter Wheel

- nominal performance, transition time even slightly shorter than in ILT

Position A

Position B



Test Results (5)

• Temperature sensors: - nominal performance for all but the two blue detector sensors- 1 sensor was recovered, apparently a contact problem on a DMC connector

• Blue detector heater: - o.k. (but thermal shimming to be improved)

• Optical performances:- no particular tests done, since no telescope/OGSE

available- straylight- FoV maps do not indicate any other problem



Test Results (6)• Ge:Ga Detector performance:

- IMT performance similar to ILT- Differences due to other background conditions: absolute level and stability - Lost a number of pixels

Rint=64, Cint=0.3pF

Rint=64, Cint=0.3pF



Test Results (6)• Ge:Ga Detector performance:

- Lost a number of pixels

Blue array : - 2 new high noise pixels

Red array : - 7 new dead pixels - 5 new high noise pixels - 1 dead pixel in ILT seems to react better to flux again, but very noisy.



Test Results (7)

• Bolometer performance: - IMT performance similar to ILT- Differences due to shorter test time and other background conditions: absolute level and stability

ILT IMT



Test Results (8)

• Bolometer performance: - IMT performance similar to ILT- Differences due to shorter test time and other background conditions: absolute level and stability

ILT IMT



Further Tests

• Not reported in this presentation:- Optimum Ge:Ga detector Bias

- S/N as a function of reset interval- Emissivity of calibration sources- Quick wavelength check (several executions

failed, one was successful)

- Memory Management- SAFE mode transition- Non-Prime PACS Switch-on- Bolometers Saturation check- Detector selection table test- Compression/Reduction Modes Test (Phot & Spec)- Time constants for flux changes in spectroscopy

• Failed Tests: (due to grating problem)- Grating relative spectral response function- Emissivity of calibration sources (failed partly)- Medium sampling grating test



AOT Tests (1)

• Overview:- Spectroscopy “TuttiFrutti” AOT ( o.k.)- Photometry “TuttiFrutti” AOT ( o.k.)[Test of all AOT relevant OBCPs, verification of PACS sub-unit synchronisation and building blocks for real AOTs]

• Spectrometer Line Scan AOT - Calibration blocks concepts - Line scan concepts - Frequency switching concepts• Spectrometer Range Scan AOT• Photometer AOT - Calibration block concepts - Nominal photometry concepts - Photometry in PACS/SPIRE parallel mode



AOT Tests (2)

• Consolidated set of AOT performance tests established for future test campaigns• Although the AOT tests are highly valuable, not everything could be tested: pointing modes, space environment effects, no external sources

• Report on “AOT related test during the EQM IMT” is in preparation, results to be presented at next PACS ICC Feb 23/24



PACS/SPIRE Parallel Mode Test (1)

Concept:- “Shifted” (by ~25-30min.) cooler recycling- SPIRE activities- Thermal behaviour test (with SPIRE on in parallel) - Two test cases: Single and Dual band photometry

- Only Line Scan AOT option tested - Dual band: blue LW, double compression

red, nominal compression - Single band: only red channel, nominal compression - 15 TM packets per sec available for PACS

data rates: PACS ~72 kbit/s SPIRE ~57 kbit/s



PACS/SPIRE Parallel Mode Test (2)

• Results:

- Thermal behaviour: o.k.- Single band photometry: o.k.- Dual band photometry: Bug in CUS script, double reduction in blue channel has been set unfortunately to nominal again

Data loss due to violation of bus bandwidth, however correctly handled by DPU.

- Overall: Successful as seen by PACS next steps to be carried out elsewhere (CUS, HSPOT…)

Overall PACS EQM IMT Analysis Contributions by PACS ICC

Documents