Advanced Concepts & Science Payloads Office Eddicam/EST MeetingPage 1 CCD Procurement Schedule driven Review off-the shelf availability Specific mode of operation – match requirements ? Review test, characterisation and calibration requirements

Advanced Concepts & Science Payloads Office Eddicam/EST MeetingPage 2 Schedule 2007 launch is the goal (match Kepler and be available for launch in the Herschel/Planck context) For the AIV campaign, need focal camera ready in 2005 (details to be evaluated with system study, e.g. need dates, serial or parallel, calibration) CCDs are the long-lead item to ensure delivery of chips for camera testing in 2004

Advanced Concepts & Science Payloads Office Eddicam/EST MeetingPage 3 Schedule (ii)

Advanced Concepts & Science Payloads Office Eddicam/EST MeetingPage 4 E2V Devices CCD 42 family – used in Megacam, COROT Set of common photo-lithographic mask components can be used to make a device 2048 w x (nx256) h Can be used with shielded store section in framestore mode for minimal image smear & fast image readout Back-illuminated, uniform response, switchable gain stage Note the E2V design team is already loaded up with new projects

Advanced Concepts & Science Payloads Office Eddicam/EST MeetingPage 5 Area vs Speed Trades Large CCD covers more target stars per observation, but serial read out increases frame period For fixed CCD full-well, longer frame time implies saturation at fainter magnitude Serial output register becomes bottleneck – speed of amplifier (<3MHz) Row binning is ”instantaneous” and serial register can accommodate ~3 – 4 image pixels Two ampliers possible – doubles video electronics resources, CCD window reconstitution at middle

Advanced Concepts & Science Payloads Office Eddicam/EST MeetingPage 6 CCD42-C0 Largest device accommodated on Si wafer 3072 x 2048 image pixels. 6 CCDs cover field of view efficiently All other parameters identical with CCD42-80

Advanced Concepts & Science Payloads Office Eddicam/EST MeetingPage 7 Modes of Operation Frame transfer, 4 (3?) rows binned to output, serial register runs 2.5MHz to one amplifier => 0.75 sec Full well implies ~13 M electrons /star/sec m v ~7.7 (assuming m =11 ~6e5, but maybe 1 mag gain via. throughput estimate?) To enhance brightness limit reduce accumulation time. Requirement of m v =5 implies reduce by >10 Either reduce height of the selected area in a CCD to 300 rows or 0.23º x 1.6 º in one CCD Or use a timed accumulation and low duty cycle in one CCD (5% live time) Needs careful management for cross-talk

Advanced Concepts & Science Payloads Office Eddicam/EST MeetingPage 8 Modes (contd.)

Advanced Concepts & Science Payloads Office Eddicam/EST MeetingPage 9 Specification ItemGoalSpecPerformance Field View6º dia. 2.5º dia4.75 º x 4.75 º Brightest starm v = 3m v = 5m v = 5 (7.7) Faintest Star Dyn. Range669.8 (7.1) * Asteroseismology requirements (check also PF)

Advanced Concepts & Science Payloads Office Eddicam/EST MeetingPage 10 Other items Improved yield and uniformity if relax the short wavelength QE requirement Noise – limited by design for high dynamic range (~15-20 electrons rms), run in low gain? E2V rely on standard silicon, so do not push for higher resistivity and enhanced red response Cosmetics - drive yield. Design the software to allow to ignore 1 pixel out of any star window – relaxed cosmetic spec. follows Radiation damage, speed vs. electronics………..

Advanced Concepts & Science Payloads Office Eddicam/EST MeetingPage 11 Testing Task Overview Three separate areas of testing to be considered vis a vis industry procurement Acceptance test against specifications Radiation damage assessment Test in support of algorithms, calibration, cosmic rays, photometric test bench etc..

Advanced Concepts & Science Payloads Office Eddicam/EST MeetingPage 12 Performance verification Does the representative prototype device meet our requirements? - Which are critical items? Explore the yield of further devices to gain handle on unit cost Measure several devices to gauge dispersion Engineering devices to test out bread-board electronics What can be done with CCD42-80? How many devices? Any front-illuminated from prototypes?

Advanced Concepts & Science Payloads Office Eddicam/EST MeetingPage 13 Batch Acceptance From the Flight Model batch verify the CCDs meet specifications E2V can (and have – Megacam ?) perform this, but a testing bottleneck Leave to industry camera team – efficient use of time and resources “Eddicam” consortium – adds a possible delay between E2V and camera team at industry that may not be viable ? Representative sampling ?

Advanced Concepts & Science Payloads Office Eddicam/EST MeetingPage 14 Radiation damage Eddington is likely a benign application w.r.t. radiation damage of charge transfer – image field is repetitive and unchanging, only stability is needed Operate at as low a temperature as possible Small change in apparent centroid, some loss of S:N Take a representative CCD42 device, and test in Eddicam mode of operation and signal levels after representative dose Bad pixel generation ?

Advanced Concepts & Science Payloads Office Eddicam/EST MeetingPage 15 Science Test performance in the modes of operation Effects of long duration photometry (cosmic rays, flickering pixels, chosen on-board algorithms etc.) Different requirements of test bench? Can be CCD42-80 ? On-ground calibration Prepare for in-flight calibration End-to-end test ? Decoupling from industry effort is efficient