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…
 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.
NCS/NICMOS Temperature
B, I, Ha
C. Long 08/15/02
J, H, Pa
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.
NICMOS Characterization: DQE
From standard star P330E:
From flat-fields:
M. Rieke
Ratio of Cal Factors
Boeker/Mazzuca
2.00
NCS/Pre-NCS
1.80
1.60
1.40
1.20
1.00
0.80
0.8
1.0
1.2
1.4
1.6
1.8
2.0
mm)
Camera 1
Camera 2
Camera 3
 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)
2.2
2.4
NICMOS Characterization: DQE
Absolute DQE,
derived from %
increase (see
previous slide)
applied to
Thermal
Vacuum data
WFPC2 B,V,I
NICMOS J,H,PaBoeker/Mazzuca
Preliminary NICMOS photometric keywords (PHOTFNU)
delivered by M. Rieke (08/08/02)
NICMOS Characterization: dark current
L. Bergeron
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 (NREADdependent) adds to the
noise budget.
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.
High DarkCurrent Pixels
in NICMOS
L. Bergeron
Dark frames:
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.
Additional On-going Characterization
 Readout noise appears to be slightly lower than the
customarily advertised 30 e-/pix/readpair. Possibly closer to 2627 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)
Torpedo
Cycle 7 NIC1
Cycle 11 NIC1
Need to ensure
instrument’s
thermal stability
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)