Download - Plato meeting MSSL Wed+Thur 15+16/Oct/08
Plato meeting MSSL Wed+Thur 15+16/Oct/08
UK interests/activities
Alan Smith and Dave Walton UCL/MSSL
Agenda
Wednesday• Organisation of project, System Group• Organisation of ‘focal plane’ WP (UK+Spain)• CCD characteristics and procurement• CCD optimal operating temperature• Characterisation, CCD, FPA, ...
Thursday• Tour of lab• Front end electronics• FPA interface definitions• AOB
UK groups with hardware interests
• MSSL• Leicester University• RAL• Astrium
Proposal submitted to STFC:
• Awaiting bridging grant• Proposal presentation/decision meeting with STFC
24/Sep/08• Final outcome expected in November
Plato proposal to STFC identifies 9 workpackages for UK
1. Preparation: UK exoplanet community
2. Preparation: UK asteroseismology community
3. CCD specification and characterisation
4. Impact of L2 environment
5. Front end electronics
6. AIV for focal planes
7. Calibration
8. End-to-end simulation
9. Data processing
Baseline
Flexible to the needsof the consortium
Themes
WP Calibration Engineering Data Centre
CCD specification & characterisation
Characterisation Specification
Radiation Damage Characterisation Shielding
Front End Electronics
Design
Thermo-mechanical design
Design
AIV focal planes Verification Assembly and Integration
CalibrationEnd-to-end simulation
Calibration Data processing
Data Centre Calibration Post launch data processing and archive
WP3. CCD Specification and characterisationUK lead: MSSL
Review PDD CCD spec wrt:
• science performance• Manufacturability• Cost• Schedule• packaging
Gaia CCD at MSSL
CCD Specs: see e.g. Payload Definition Doc (PDD)• Flight: 28 telescopes, 4 CCDs per telescope• Each CCD 3584x3584 18µm pixels• Full-frame (except for 2 bright-source telescopes
using same chip but frame transfer)
~150 CCDs
CCD specs (continued)
• 4-phase IФ• Back-illuminated, AR coated, wavelength range
TBC, ~400-1000nm• 2 readout ports, ~4Mpix/s, <20e- rms• SiC package (TBC) with flexi• 2- or 3-side buttable, metallisation of bus lines
CCD open issues
• Integration of JFET (or even controller and/or readout electronics) into CCD package
• Operating temperature: baseline 170K, higher T easier to implement but need to assess effect on trap/release
CCD characterisation• Prototype
– Design verification– In depth charaterisation– Sub-pixel characterisation– Calibration process trials– General optimisation including FEE
• CCD (E2V)– Acceptance testing
• CCD (MSSL)– Delta acceptance (tbc)– Characterisation– Optimisation
• Focal Plane– Noise, alignment– Function
• Telescope– PSF– Function
• Spacecraft– Co-alignment– Function
• In-flight
• Characterisation• Linearity (including Full-
Well domain)• Full-Well• Noise• CTE• Responsivity• Gain• Flat field
• Vs• Temperature• Drive voltages• Wavelength
WP7. CalibrationUK lead: MSSL
• Develop overall scheme to integrate calibration at all levels and be complementary to in-flight calibration practicalities
WP6. AIV for focal planesUK lead: MSSL
• Study verification (Test) strategy at Payload level, to be consistent with calibration strategy (see WP7)
WP8. End-to-end simulationUK lead: MSSL
• Co-ordination with Denmark• Definition of CCD performance model• Definition of focal plane performance model• Consideration of model requirements wrt post-
launch analysis.
WP4. Impact of L2 environment on CCD performanceUK lead: Leicester University
• CCD Requirements study• L2 environment study: radiation and dust• Impact of environment on CCD, shielding• Review of previous and current studies/missions• Scientific impact of above assessments
• Dose: Ionising ~8 Krad(Si)Non-ionising ~5e9 p cm-2
WP5: Front end electronicsUK lead: MSSL
• Analysis and decomposition of Science Requirements and PDD
• Generation and assessment of FEE design options
• Analysis of compatibility of optimum design wrt Science Requirements and payload constraints
• Support to Spain’s thermo-mechanical design work
PEM, developed for ESA Gaiacontract with RAL, Astrium
Front end electronics
• Integrated in CCD package?• 16-bit, 4Mpix/s, 2 ports per CCD. Described in
PDD as “modest extension” to existing components, but suitable rad-hard ADC may be a challenge
• Integral non-linearity important for photometry• Differential non-linearity important for small deltas
(asteroseismology and transits). GATTI scaling may be required.