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NICMOS post-cooldown detector performance

NICMOS post-cooldown detector performance. 1) SMOV status 2) Dark current 3) Quantum efficiency 4) “First light”, focus and image quality 5) SMOV outlook. Thermal history since NICMOS switch-on (on April 19). Transition to detector control. Transition to Ne control. Setpoint to 72.5 K.

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NICMOS post-cooldown detector performance

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  1. NICMOS post-cooldown detector performance 1) SMOV status 2) Dark current 3) Quantum efficiency 4) “First light”, focus and image quality 5) SMOV outlook

  2. Thermal history since NICMOS switch-on (on April 19) Transition to detector control Transition to Ne control Setpoint to 72.5 K Setpoint to 72 K

  3. X X X X

  4. Filter wheel test(G. Schneider, K. Noll, L. Mazzuca, E. Roberts) • NICMOS filter wheels have motion sensor only on the motors, not on the wheels themselves • Concern about breaking the wheel shaft in case of mechanical contact/blockage • careful “two step forward, one step back” approach with analysis of motor currents and flat field images • so far, so good: verified normal motion over 9/10 of a full turn • side benefit: early measurement of DQE (and more….)

  5. Mean: 0.166 e-/s Mean: 0.114 e-/s Mean: 0.148 e-/s • NICMOS dark current • (C. Xu) • preliminary measurements indicate that dark current is nominal, i.e. close to Cycle 7 • “bump” is NOT observed

  6. The first flat field images Then… (1998, T=62 K) Now… (2002, T= 77K) NIC1 NIC2 NIC3

  7. DQE – comparison with expectations

  8. Serendipitous image of a crowded star field (…taken out from electronic distribution as requested by HST project…) Camera 2 in H-band (F160W) FWHM: 2.17 pixels (0.163“) (very close to nominal!)

  9. First assessment of image quality: (G. Schneider) • VERY close to nominal focus • some coma, to be corrected with tilt adjustment of PAM (in time for ERO observations) Mean PSF from 2002 stellar field (NIC1, F095N) 1997 PAM tilt grid (NIC1, F095N)

  10. NICMOS SMOV: early activities timeline

  11. Summary - NICMOS has survived its 28 month hiatus without any significant degradation - performance is nominal so far - GO science will be enabled within 2 weeks

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