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NICMOS Status

NICMOS Status. Daniela Calzetti. Presentation for TIPS, 08/15/2002. Instrument Status. NICMOS detectors’ temperature continues to be stable under NCS control Default plan is to tweak NCS control temperature as needed to keep detectors at constant T, should it become necessary. Old habits…

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NICMOS Status

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  1. NICMOS Status Daniela Calzetti Presentation for TIPS, 08/15/2002

  2. Instrument Status • NICMOS detectors’ temperature continues to be stable under NCS control • Default plan is to tweak NCS control temperature as needed to keep detectors at constant T, should it become necessary. • Old habits… • On July 23rd, an Intel exception caused NICMOS to suspend. A few parallel exposures (GO-9484) were lost. • Two SEUs caused TPG resets in NIC1 (July 31st) and NIC3 (Aug. 11th), with consequent powering off of the affected detectors. In the first instance, no NICMOS exposures were lost. In the second, one exposure (possibly 2) of GO-9484 affected.

  3. NCS/NICMOS Temperature B, I, Ha J, H, Pa C. Long 08/15/02

  4. NICMOS SMOV3B • Almost done …. • The remaining program, ID 8984 `Coronographic Performance Test’ (6 orbits), due to execute in early August, was delayed due to higher priority GO science; • Three orbits will execute in the week of August 19th (SMS231). • Three orbits delayed until October because of target unavailability; these observations re-determine the position of minimum scattered light under the coronograph (`sweet spot’). Carl Biagetti asked to move these three orbits to Cycle 11 calibrations and TTRB approved on 08/13/02. • Officially NICMOS SMOV3B ends in late August.

  5. NICMOS Characterization: DQE From standard star P330E: From flat-fields: M. Rieke Boeker/Mazzuca • Flat-fields and standard star measurements show consistent increase in DQE from 62 K to 77 K (~60%-70% at 1 mm and ~20%-25% at 2 mm)

  6. NICMOS Characterization: DQE Absolute DQE, derived from % increase (see previous slide) applied to Thermal Vacuum data Boeker/Mazzuca WFPC2 B,V,I NICMOS J,H,Pa Preliminary NICMOS photometric keywords (PHOTFNU) delivered by M. Rieke (08/08/02)

  7. NICMOS Characterization: dark current Linear dark current only is 0.1-0.2 e-/s/pix, about 3-4 times higher than in Cycle 7/7N. N.B.: as usual, the amplifier glow (NREAD-dependent) adds to the noise budget. L. Bergeron Plan is to advertize 0.3 e-/s/pix in ETC and Instrument Handbook for S/N calculations. However, NICMOS observations are generally not dark current-limited.

  8. High Dark-Current Pixels in NICMOS A longer tail of high dark current pixels than in Cycle 7/7N (few % of total pix). Fully correctable. Some high d.c. pixels will saturate earlier in the presence of bright targets. L. Bergeron Dark frames:

  9. Additional On-going Characterization • Readout noise appears to be slightly lower than the customarily advertised 30 e-/pix/readpair. Possibly closer to 26-27 e-/pix/readpair (Boeker/Xu) • Detector’s linear dynamic range (<10% non linearity) is about 10% lower than Cycle 7/7N, as expected (Boeker/Sosey) • Number of hot/cold pixels about 50% higher than in Cycle 7/7N, now being ~110-150 pixels, depending on the Camera (Bergeron). New large piece of grot appeared in NIC1 (Sosey) Need to ensure instrument’s thermal stability Torpedo Cycle 7 NIC1 Cycle 11 NIC1

  10. Pipeline/Data Analysis • NICMOS OTFR is running Temp-dependent darks since last April. • Pipeline still running Cycle 7/7N reference files. • 13/19 (NIC1), 15/19 (NIC2), 19/19 (NIC3) Cycle 11 flat-fields delivered to CDBS. Awaiting installation. Data for remaining in hand (Mazzuca) • Preliminary Dark Reference files (Temp-independent) circulated among NICMOS group (08/14/02, Bergeron). In testing. • Post-SAA CR persistence analysis started. Preliminary analysis indicates no change in CR decay time relative to Cycle 7/7N (Dickinson/Sosey)

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