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Electronics power

Electronics power. FPA electronics heat load. Revised for 144 fixed filter CCDs. CCD Power. HgCdTe Power. Assume the devices are constantly being read out. LBNL CCD development. CCD Technology. LBNL 2k x 2k. First large format CCD made at LBNL 2k x 2k, 15  m pixels.

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Electronics power

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  1. Electronics power

  2. FPA electronics heat load Revised for 144 fixed filter CCDs.

  3. CCD Power

  4. HgCdTe Power Assume the devices are constantly being read out.

  5. LBNL CCD development

  6. CCD Technology

  7. LBNL 2k x 2k First large format CCD made at LBNL 2k x 2k, 15 m pixels. 1980 x 800, 15 m pixels.

  8. LBNL 2k x 4k USAF test pattern. 1478 x 4784 10.5 m 2k x 4k 15 m 1294 x 4186 12 m

  9. Commercial 2k x 4k • Includes • 982 x 935 (15 mm)2 • 1230 x 1170 (12 mm)2 • 1402 x 1336 (10.5 mm)2 • 1636 x 1560 (9 mm)2 • 25202 (12 mm)2 • 28802 (10.5 mm)2 • 2048 x 4096 (15 mm)2 • 5122 & 1024 x 512 (15 mm)2 Amplifier studies (noise) • 1200 x 600 (15 mm)2 2-stage amplifiers for high-speed readout Front illuminated

  10. Noise measurements (Lot 75091, 512 x 512)

  11. Erasure of persistence images Erase Flood exposure 2k x 2k @ -150C

  12. Linearity and Well Depth • Saturation curve obtained by plotting peak projected spot intensity versus exposure time. • Full-well capacity in electrons obtained by scaling ADU’s by CCD gain. • 15 m pixels • Well depth about 170 ke • Linearity is about 0.3%. • Well depth is a function of pixel size (preliminary). • 12 m well depth found to be 150 ke. • 10.5 m well depth found to be 150 ke.

  13. LBNL 2k x 2k Quantum Efficiency

  14. LBNL CCDs in action

  15. LBNL 2k x 2k results Image: 200 x 200 15 m LBNL CCD in Lick Nickel 1m. Spectrum: 800 x 1980 15 m LBNL CCD in NOAO KPNO spectrograph. Instrument at NOAO KPNO 2nd semester 2001 (http://www.noao.edu)

  16. LBNL CCD’s at NOAO Science studies to date at NOAO using LBNL CCD’s: • Near-earth asteroids • Seyfert galaxy black holes • LNBL Supernova cosmology Cover picture taken at WIYN 3.5m with LBNL 2048 x 2048 CCD (Dumbbell Nebula, NGC 6853) Blue is H-alpha Green is DIII 9532Å Red is HeII 10124Å. See September 2001 newsletter at http://www.noao.edu

  17. LBNL Supernova Spectrum at NOAO

  18. Radiation damage studies Two set of four devices each. Both sets have notch implant in serial registers. Only one set has notch implant in parallel register. Radiation doses are 5, 10, 50, and 100 x 109 protons/cm2 at 12 MeV. Note, 1x109 protons/cm2 @ 12 MeV is 1.5x107 MeV/g NIEL.

  19. CTE vs proton flux CTE is measured using the 55Fe X-ray method at 128 K. The readout speed is 30 kHz, the X-ray density is 0.015/pixel.

  20. Improved Radiation Tolerance on “notch” implant devices

  21. CTE Dependence on Temperature

  22. Dark Current Degradation

  23. 208K 158K Dark Current vs Temperature Fit gives expected Si bandgap, so no new dark current sources are developing. The plateau at right is not identified yet, but could be surface leakage currents.

  24. Comparison to Conventional CCDs converted to NIEL dose

  25. P-channel high-resistivity CCDs show better radiation tolerance against CTE degradation than n-channel devices. • Dark current remains low even after proton doses equivalent to decades in space.

  26. Packaging Developing a solution common for ground and space telescopes

  27. Connector PCB Glue Invar/Moly/AlN base Glue Si Detector Wirebonds CCD Outline • Support CCD • Connection to cold plate • Four-side abuttabe for dense mosaic. • Built-in mechanical precision – no shimming. • Access to bonding pads • Local electronics • Cable connector • Low mechanical stress in silicon from -150 C to +150 C. • Low background radiation materials • Low chemical reactivity with silicon

  28. Assembly fixture Precision Mo spacers defining mount base to CCD optical surface. Weight can be applied here if needed. Optically polished Mo base plate. Vacuum chuck for CCD Cam to lower CCD onto mount EA9361 epoxy is stenciled onto mount as an array of dots. Final epoxy thickness is ~500 microns; established from measurements of epoxy characteristics and need to reduce shear transfer into silicon due to differential CTE.

  29. Packaging prototypes 2k x 2k back-illuminated mount. 2k x 4k mount similar, extending along wire-bond edge. First back-illuminated image with new mount. CCD is engineering grade used for assembly practice.

  30. HgCdTe

  31. SNAP Visit 04-02-01 Rockwell Competition Sensitive

  32. SNAP Visit 04-02-01 Rockwell Competition Sensitive

  33. SNAP Visit 04-02-01 Rockwell Competition Sensitive

  34. HgCdTe dark current and readnoise • Per D. Hall and J. Garnett, MBE dark current at 140K is 0.02 e-/s/pixel. • Read noise per Rockwell • ~ 10 e- rms CDS; • ~ 3 e- rms multiply sampled

  35. SNAP fixed filter focal plane study Focal plane is kept at fixed orientation to observation fields for 3-month periods. Focal plane is striped through 1o x 10o field, one north and one south.

  36. FPA GROWTH UNIT CELL Q1 Q2 Q4 Q3 3-month rotation 1O X 10O SNAP FIELD

  37. TMA62 optics • I use TMA62 in the following examples. • Per Mike Lampton: • Focal length to 21.66 meters • Rinner = 0.006 radians • = 0.3438 deg • = 129.120 mm • Router = 0.013 radians • = 0.7449 deg • = 283.564 mm • Annular sky area = 1.37 sq deg

  38. 900 symmetry

  39. 6+4 filter scheme 1+z scaled CCD filters Fixed width HgCdTe filters CCDs intra-overlap 45% HgCdTe intra-overlap 25% CCD and HgCdTe overlap from 900 nm to 1000 nm

  40. S/N calculation Optimize Nexp and Texp for a few realistic cases of Npix , DC, and RN. Note: for now, I lump RN and EN together. For an illustrative simplification, set G=DC=RN=EN=0:

  41. S/N weights Weights Let’s make each HgCdTe filter have twice the effect area of a CCD. Let’s take advantage of time dilation for higher z objects. Individual measurements made for a z  0 object every 4 days are equivalent to the co-added measurements from two consecutive 4-day periods for a z  1 object.

  42. S/N obtained for Texp = 200 s with weights

  43. Fixed filter summary • 0.34 sq. deg. in 144 CCDs • 0.34 sq. deg. In 36 HgCdTe (excluding ancillary ones) • 0.53 Gpixel • For 20 fields: • 1150 SNe/yr with z < 1.2 • 780 SNe/yr with z > 1.2 • Photometry time is 5350 hrs for 200 second exposures and 20 seconds readout time. • Spectroscopy time is 3060 hrs (Jay’s R=150, S/N=10). • 8410 hrs used out of 8760 available. • (Results above have to be derated by orbit inefficiencies.) • Fewer pixels and constant exposure time reduces telemetry BW to 25 Mbs DC and requires very little buffer memory.

  44. CCD support electronics

  45. Readout Electronics Concept • CDS – Correlated Double Samples is used for readout of the CCDs to achieve the required readout noise. • Programmable gain receiver, dual-ramp architecture, and ADC buffer. HgCdTe compatible. • ADC – 16-bit, 100 kHz equivalent conversion rate per CCD (could be a single muxed 400 kHz unit). • Sequencer – Clock pattern generator supporting • modes of operation: erase, expose, readout, idle. • Clock drivers – Programmable amplitude and • rise/fall times. Supports 4-corner or 2-corner • readout. • Bias and power generation – Provide switched, • programmable large voltages for CCD and local power. • Temperature monitoring – Local and remote. • DAQand instrument control interface – Path to data buffer memory, master timing, and configuration and control.

  46. CDS ASIC • LBNL has a long history in rad hard ASIC design for high energy physics. • We have submitted a CDS to DMILL. • We have simulated 0.8 m and 0.25 m CMOS implementations. • Timely developments in the commercial realm is work on HV sub-micron processes for flat panel displays may make a single chip solution possible.

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