Torsten Böker TIPS May 2, 2002 NICMOS post-cooldown detector performance 1) SMOV status 2) Dark...
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Transcript of Torsten Böker TIPS May 2, 2002 NICMOS post-cooldown detector performance 1) SMOV status 2) Dark...
Torsten BökerTorsten Böker TIPS TIPS May 2, May 2, 20022002
NICMOS post-cooldown detector performanceNICMOS 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 K
Setpoint to 72.5 K
X
X
XX
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….)
NICMOS dark current(C. Xu)
-preliminary measurements indicate that dark current is nominal, i.e. close to Cycle 7
- “bump” is NOT observed
Mean: 0.166 e-/sMean: 0.114 e-/sMean: 0.148 e-/s
Then…(1998, T=62 K)
Now…(2002, T= 77K)
The first flat field images
NIC1 NIC2 NIC3
DQE – comparison with expectations
Serendipitous image of a crowded star field
Camera 2 in H-band (F160W)
FWHM: 2.17 pixels (0.163“)
(very close to nominal!)
(…taken out from electronic distribution as requested by HST project…)
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)
1997 PAM tilt grid (NIC1, F095N)
Mean PSF from 2002 stellar field (NIC1, F095N)
4/19 Fri 109 NICMOS restarted, Ne-loop control continues
4/22 Mon 112 Change to mounting cup control
4/23 Tue 113 Return to Ne control, Filter wheel test begins
4/26 Fri 116 Increase control temperature to allow for seasonal margins +2 K
4/29 Mon 119 Begin darks every 3rd orbit
4/30 Tue 120 DQE test visit 1; Control temp +0.5 K
5/02 Thu 122 DQE test visit 2; Control temp –1.0 K
5/03 Fri 123 Filter wheel test complete; Focus sweep, FOM test, Transfer function test
5/04 Sat 124 DQE test visit 3; Control temp +0.5 K (TBD)
5/06 Mon 126 DQE test visit 4; Stop darks
5/08 Thu 129 Final temperature set point (TBD)
5/10 Sat 131 EROs begin, flats, thermal background
5/16 Fri 137 Final focus update, GO science enabled, remaining SMOV begins
NICMOS SMOV: early activities timeline
Torsten BökerTorsten Böker TIPS TIPS May 2, May 2, 20022002
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