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Published byLewis Holt Modified over 9 years ago
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ACS STATUS Linda Smith (thanks to David Golimowski for providing the slides)
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ACS was repaired in EVA 3: four circuit boards in CEB were replaced and a new LVPS was installed.
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Part 1: WFC CEB-R FT Criterion: At least one WFC CCD is operational and can be read out through at least one amplifier Result: Both CCDs and all four amps are operational Criterion: At least one WFC CCD amplifier operates with RN~10 e- Result: All amps operate with read noise 3.0 – 3.6 e- (prescan only) in DSI mode assuming gain=1 The WFC TECs can cool focal plane to its max set point (-66.7 C) while operating at < max power, thus operational T < -81 C is achievable (Passed) Shutter operates (Passed) FW2 can be rotated and FW1 left in open position (Passed) WFC commanding and data readout, storage, and dump are possible (Passed)
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Part 1: WFC CEB-R FT Four-amp bias frame (DSI) Bias level: 2260-2600 DN RN: 3.0-3.6 e- (prescan) 3.9-4.4 e- (image area) Four-amp lamp frame (F814W, DSI) Signal level: 22000-26000 DN Nearly identical to Jan 2007 flat!
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Part 2: ACS-R System FT Initial execution halted due to HRC electrical short * +35V and +15V did not come up properly & backpower current was higher than expected (~2.2 A vs. ~1.2-1.4 A) Reran System FT with all HRC commanding deleted * WFC DSI images showed same RN as in CEB-R FT * WFC C&S images showed pre-Jan 2007 RN levels * SBC dark exposure improperly truncated but nevertheless demonstrated that valid science image can be acquired and that SBC functionality has been preserved Two baseline O-mode images were obtained to verify oscilloscope functionality (not part of formal pass/fail criteria)
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Part 2: ACS-R System FT Criterion: At least one WFC CCD is operational and can be read out through at least one amplifier Result: Both CCDs and all four amps are operational Criterion: At least one WFC CCD amplifier operates with RN~10 e- Result: All amps operate with read noise 3.0 – 3.5 e- (DSI) and 4.0 – 4.6 e- (C&S) The WFC TECs can cool focal plane to its max set point (-66.7 C) while operating at < max power, thus operational T < -81 C is achievable (Passed) Shutter operates (Passed) FW1 can be rotated and FW2 left in open position (Passed) WFC commanding and data readout, storage, and dump are possible (Passed)
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Part 2: ACS-R System FT Four-amp bias frame (C&S) Bias level: 4750-5000 DN RN: 4.0-4.6 e- (prescan) 4.8-5.5 e- (image area) SBC, ~35 sec flat, -50 V on MCP Signal level: 0 DN No interference or noise detected
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Thumbs-Up Around the World (and Above It!)
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