Overview on PACS In-flight Commissioning and Performance Verification. PACS Science Verification Review Phase 1 MPE, 22/23 June 2006

Transcription

1 Overview on PACS In-flight Commissioning and Performance Verification PACS Science Verification Review Phase 1 MPE, 22/23 June 2006 U. Klaas (Max-Planck-Institut für Astronomie) PACS ICC Calibration Working Group

2 PACS Instrument In-flight Commissioning - PACS in-flight commissioning plan and program will be built up from FM-ILT and IST test experience. - IMT-type full functional and short performance check-out can be performed with internal stimulators. - In addition verification and adaptation of instrumental zero points after launch and under non-gravity conditions, e.g. mechanical zero point of chopper as reference of angular calibration of instrument.

3 PACS Instrument In-Flight Performance Verification - PACS Performance Verification Plan will evolve from PACS Calibration Document (PCD): - PCD flags calibration requirements to be performed in PV - PCD indicates frequency of repetition or need for monitoring - PCD gives time estimate for measurement performance - Major revision now for Draft 8, e.g. bolometer measurement strategy changed from CQM to FM model - Draft 8 of PCD is in progress and will be the first upgrade - refering to FM-ILT tests - making references to CQM-ILT and EQM-IMT test reports and cal files - In-flight test design: FM-ILT performance and calibration tests (see presentation on FM-ILT test plan) will be the building blocks: replace OGSE stimulators by celestial standards.

4 PACS Instrument In-Flight Performance Verification - Issue 1 of PCD after end of FM-ILT: - consolidation of FM-ILT related requirements - revision of non-fm-ilt relevant requirements, e.g. pointing, telescope, cross-calibration - revision of introduction and overview sections - address in more detail PV - prepare the grounds for an efficient science verification (AOT tests on well characterised (faint) targets)

5 Preparation of celestial standard data bases Photometric standards - Stars: faint source references, also for sensitivity verification (science verification) - Asteroids: largest flux range coverage - Planets (Uranus & Neptune) bright end, linearity issues. Wavelength standards - Planetary Nebulae and HII regions (ISO LWS calibrators) - Stars with water emission lines Spatial (astrometric) standards - Double stars - Double galaxy nuclei - Asteroid conjunctions - Planetary satellites (straylight issues)

6 Preparation of celestial standard data bases, continued Secondary standards - Better sky coverage for shorter slewing times Coordinated efforts - Strong contributions from PACS team to provision of SED data bases - observing and modelling of stellar SEDs under way at KUL - observing and modelling of asteroid SEDs under way by T. Müller (MPE) and colleagues - Coordination of activities via HCalSG, e.g. common sources for PACS and SPIRE - Participation in Herschel calibration source workshops

7 Challenges and new issues for Performance Verification Adaptation to telescope background - settings of internal calibration sources - detector gains and offsets, reference voltages - telescope background drifting during transfer phase follow this up in Herschel Calibration Steering Group - perform PV ODs like later in Routine Phase, i.e. 1 instrument per operational day (ISO: 1 instrument per PV revolution, all instruments during routine revolutions different thermal balance)

8 Challenges and new issues for Performance Verification, continued Operation of Ge:Ga detectors under ionising radiation - final bias settings reduced bias compensated by increasing responsivity up to a saturation level - frequency of curing more nominal bias and curing after a few hours - definition of operational framework (e.g. need for curing at begin of each PACS spectrometer operational day) - extensive γ-radiation tests in the lab to support the decisions. - coordination with results from radiation probe onboard (HCalSG) - procedures for peculiar space weather, e.g. solar storms (HCalSG) - glitch handling of compressed data - compensation of responsivity jumps