PACS SVR22/23 June 2006 PACS Thermal Behaviour1 PACS Thermal Behaviour Tests T. Müller, H. Feuchtgruber, A. Contursi, Cs. Kiss, Sz. Csizmadia

PACS SVR22/23 June 2006 PACS Thermal Behaviour2 Available Reports Thermal Behaviour Tests During EQM IMT: SPEC & PHOT, PACS-ME-TR-067, issue 1.0 Blue Spectrometer Temperature Sensor Variation – EQM IMT PACS-ME-TR-066, issue 1.0 Comparison of the nominal and the PACS/SPIRE parallel mode cooler Recycling procedures Cooler Holdtimes of the Photometer Focal Plane Unit, PICC-KO-TR-004, Draft 0.1 As part of the PACS ILT report: Cooler Recycling Procedure of the Photometer Focal Plane Unit AVM/CQM ILT Thermal Behaviour Tests during CQM ILT: SPEC & PHOT

PACS SVR22/23 June 2006 PACS Thermal Behaviour3 PACS EQM Cryostat Environment To be compared with IST and TV/TB Environment

PACS SVR22/23 June 2006 PACS Thermal Behaviour4 FM IST Cryostat Environment Closed ! (drifting) Tilt may affect Red Ge:Ga strap Full

PACS SVR22/23 June 2006 PACS Thermal Behaviour5 FM TV/TB Cryostat Environment Empty Tilt may affect Red Ge:Ga strap

PACS SVR22/23 June 2006 PACS Thermal Behaviour6 In-Flight Cryostat Environment Empty

PACS SVR22/23 June 2006 PACS Thermal Behaviour7 Thermal Behaviour Test: Spectroscopy (1) Problems: - He leak - Bugs in the script - Blue detector temperature sensors where not functional Remarks: - Two cover heat-up activities took place during the test, causing some impact on L1 temperatures - General upward drift of L1 temperatures, probably due to cryostat operations - Significant increase of Red detector temperature in second half of the test probably due to the He-leak effects and combined with the cryostat operations. - The internal calibration sources were not switched-on due to a bug in the command script

PACS SVR22/23 June 2006 PACS Thermal Behaviour8 Thermal Behaviour Test: Spectroscopy (2)

PACS SVR22/23 June 2006 PACS Thermal Behaviour9 Thermal Behaviour Test: Spectroscopy (3)

PACS SVR22/23 June 2006 PACS Thermal Behaviour10 Blue Detector Heating in Spectroscopy I heater =200µA I heater =100µA After Recovery of Temperature Sensor: DECB_TS_2_3 Input to thermal shimming for FM

PACS SVR22/23 June 2006 PACS Thermal Behaviour11 Thermal Behaviour Test: Photometry (1) Problems: - He leak - Bugs in the script - excessive dissipation by bolometer group 5 (PACS-ME-NCR-163) - Timing FPGA parameters problem DMC (PACS-ME-NCR-159) - DPU CFM generated corrupted data Remarks: - Executed 4 times (2 with leak, 1 without, 1 parallel mode) - Ideally, more time would be required to see stabilization of CSs The PACS/SPIRE parallel mode worked from the thermal point of view, at the He-mass flow given during EQM IMT.

PACS SVR22/23 June 2006 PACS Thermal Behaviour12 Thermal Behaviour Test: Photometry (2)

PACS SVR22/23 June 2006 PACS Thermal Behaviour13 Thermal Behaviour Test: Photometry (3) with Bias group 5 problem without Bias group 5 problem, during parallel mode PACS-ME-NCR-163

PACS SVR22/23 June 2006 PACS Thermal Behaviour14 Cooler hold Time with He-leak End of 2h10m Recycling Procedure

PACS SVR22/23 June 2006 PACS Thermal Behaviour15 Cooler hold Time without He-leak only little detector operation during cooler hold time ! ~40 hours End of 2h10m Recycling Procedure

PACS SVR22/23 June 2006 PACS Thermal Behaviour16 Thermal Behaviour Conclusions Do not run a test with a He-Leak. Consequence: Non-Nominal He- flow scheme due to main tank leak Absolute L1 He-flow more than a factor 10 larger than specified for FM [spec. (IID-A) = 2.1 mg/s ; actual >25 mg/s] L1 temperatures became stable only towards the end of the test phase Photometry: bias group 5 problem caused anomalous heat dissipation Overall thermal behaviour of PACS was within expectations and comparable to ILT Cooler hold time too short, even with little bolometer operations: Recy. Opt. + improved cooler filling; Cover-T ? L1-T ? Straps ? Leak ? Cryo-cover, L2, L1 and L0 temperatures should be kept constant during thermal behaviour tests The malfunction of at least one blue spectroscopy detector could be recovered to obtain the required FM design information. Stabilized value of DM_CAL_SRC temperature not visible due to time constraint Steep learning curve for implementation of related commanding scripts