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TIPS meeting – Feb 21, 2002

TIPS meeting – Feb 21, 2002. WFC3 Status (detectors) M. Robberto. UVIS CCD. IR FPA / Mux. CCD Status. Marconi has completed all deliveries. Original order of 6 devices. One (# 23) damaged back in Nov 01 and returned to Marconi for analysis

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TIPS meeting – Feb 21, 2002

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  1. TIPS meeting – Feb 21, 2002 WFC3 Status (detectors) M. Robberto UVIS CCD IR FPA / Mux

  2. CCD Status • Marconi has completed all deliveries. • Original order of 6 devices. • One (# 23) damaged back in Nov 01 and returned to Marconi for analysis • Four (# 18 & # 178 and # 37 & # 40) selected for flight and characterized. • One held in reserve. • Supplemental order of 2 devices. • Both (# 48 and #50) received, characterization of #38 underway in the DCL. • Closeout meeting held on 15 January 2002. • Last detectors #37, #40, #50 shipped at Ball next week • These are exceptional devices, with extremely uniform behavior from device to device.

  3. WFC3 CCD Innovations • Low readout noise. • Improves narrow-band and UV imaging sensitivity and enables shorter sub-exposures in a long integration (providing more redundant images or more thorough drizzling). • Will challenge the instrument electronics. • High near-UV QE. • Major WFC3 scientific thrust is enabled. • Extremely uniform detector spatial response. • Simplifies calibration and improves photometric accuracy. • Charge injection for CTE degradation mitigation. • Slows down effective device aging. • Fringing characterization and prediction for long wavelength observations. • Improves accuracy of narrow-band and narrow-line observations.

  4. Marconi CCDs HaveVery Low & Consistent Readout Noise Read Noise For Marconi CCD43 Engineering Grade Devices Read Noise For Marconi Flight Candidate Devices Flight pair number 1 --- Flight pair number 2 candidates --- By comparison, the SITe devices in the ACS instrument have read noises in the range 4.5-5.5 e-

  5. Marconi CCDs Exceed Expectations for High UV QE Pair Number 1 flight CCDs versus the Specification

  6. IR-FPA Status  In addition, MUX #10 was delivered to Ball and is being integrated into the surrogate IR detector build

  7. Rockwell Test Results

  8. RSC Dark Current and QE Results min The dark current and QE performance of the detectors showed dramatic improvement over the course of the program 100% 100% min

  9. Dark current FPA15: DC= 0.04e/s @ 150K FPA18: DC= 0.34e/s @ 150K FPA22: DC= 0.39e/s @ 150K

  10. FPA31 dark current ramps FPA31 10800s exposure C. Hanley 11 Jan 2002 • Ramp slope decreases with time • Second read decreases with time

  11. FPA31dark current settling time Cycle power A sequence of 20 ramps 3 hr long, each with 1+16 samples (one every 675s) 1day 2days

  12. FPA31 dark current settling time Cycle power { CEIS FPA31 dark current settles after ~ 2 days 1day 2days

  13. FPA31 dark anomaly FPA31 appears to have two populations of pixels, each with their own dark current behavior. November 01 data

  14. FPA31 dark – 2 populations 1hr 1hr 1hr October 24 data

  15. Dark current summary • FPA31 dark current is ~0.05e/s/pix,once the FPA is set. • Settling time is ~36 hr. • For the first ~36 hr the dark current is dominated by a large drift in the output signal. • Irregular behavior still present after 36 hr on short ramps. • The drift is similar to the “reset anomaly”, but it has larger time-scale and is related to the FPA power cycling. Reset anomaly can be corrected. • Power cycling of IR FPA is not expected to routinely occur on WFC3.

  16. Quantum efficiency FPA31 January 11 data

  17. active area electrons 36 34 32 30 SB Jan 16,2001 Readoutnoise inboard electrons 12 10 8

  18. Readout noise • FPA#15: 32 e/pix/read • FPA#18: 30 e/pix/read • FPA#22: 30 e/pix/read • FPA#25: 28 e/pix/read • FPA#31: 31 e/pix/read Summary of the RON measured on active pixels

  19. Reference pixels 4507 horizontal 1507 horizontal 1014  1014 active pixels 1507 vertical 4507 vertical 1014  5 reference pixels

  20. Fixing reference pixels Vertical reference pixels are “light sensitive” Adding a delay time at the beginning of each line read eliminates the effect

  21. Reference pixels drift in 60hr Reference pixels are stable within ~100e over a time-scale of ~2.5 days

  22. CONCLUSIONS FPA 31 has been deeply investigated • QE above Performance Specs at l>1.35mm OK below Minimum Specs at l<1.2mm NO • Dark Current meets specs by a factor ~4, but • Needs ~ 36hr to settle ?? • Irregular behavior common for short exposure times NO • RON ~30 electrons/read NO • Linearity and well depth OK • Amplifier glow OK • Cosmetic OK • Reference pixels OK

  23. Latest news • One between FPA#31 or FPA#33 to be delivered next week • Rockwell has produced two extra non-flight parts, FPA#35, #36 currently under test. Preliminary data confirm QE and RON measured at DCL. • Rockwell has delivered to UH (D. Hall) a detector with 5mm material and HI-1R MUX for RON test. • Rockwell has agreed to grow LOT 5. Expected 6-8 weeks for PECs/test device data and 4 months for flight parts. • Contractual issues worked on. • New plan for 2nd detector build under discussion with BALL.

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