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 needs of the consortium

Themes WPCalibrationEngineeringData Centre CCD specification & characterisation CharacterisationSpecification Radiation DamageCharacterisationShielding Front End Electronics Design Thermo- mechanical design Design AIV focal planesVerificationAssembly and Integration Calibration End-to-end simulation CalibrationData processing Data CentreCalibrationPost launch data processing and archive

WP3. CCD Specification and characterisation UK 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 3584x µm 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, ~ nm 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. Calibration UK lead: MSSL Develop overall scheme to integrate calibration at all levels and be complementary to in-flight calibration practicalities

WP6. AIV for focal planes UK lead: MSSL Study verification (Test) strategy at Payload level, to be consistent with calibration strategy (see WP7)

WP8. End-to-end simulation UK 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 performance UK 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 electronics UK 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 Gaia contract 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.