| QC PLOTS |
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CURRENT |
HISTORY |
| DARK SM |
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| DETMON linearity |
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| DETMON gain |
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| QC1 uves_dark database (advanced users):
browse
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plot
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| QC1 uves_lingain
database:
browse
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plot
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Click on CURRENT to see the last trending (Health Check).
Click on HISTORY to see the historical evolution of the trending. |
The detector trending is based on the measurement
of QC1 parameters of DARK and Detector Linearity data. It is
obtained with dedicated Health Check OBs executed approximately monthly.
The DARK OBs obtain 4 sets of DARK data, 2 sets in BLUE mode and
2 sets in RED mode, each set comprising three 3600 second RAW frames.
The 2 sets in each mode are acquired in the two main CCD ReadOut
modes; 225kHz, low gain, 1x1 binning amd 50kHz, high gain, 2x2
binning.
The Detector Linearity OBs obtain 4 sets of BIAS and Imaging Flat
Field data, 2 sets in BLUE mode and 2 sets in RED mode, each set
comprising five BIAS RAW frames and ten pairs of Flats with exposures
times for each pair selected to sample the full well potential of the
detector. The 2 sets in each mode are acquired in the two main CCD
ReadOut modes; 225kHz, low gain, 1x1 binning amd 50kHz, high gain, 2x2
binning.
These data thus give detailed charateristics for all THREE
UVES CCDs, one BLUE and two RED (UPPER and LOWER). Trending is
provided for:
mean_dark normalized to 3600 secs exposure time (QC1 database table uves_dark, column current_dark)
Description: The mean value reported by the MIDAS command stat/image
computed on the entire chip is divided by the exposure time in sec and
then multiplied by 3600 sec.
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top
Detector-Linearity-Results |
QC1 parameters
- Effective non-linearity correction (QC1 database table uves_lingain, column lin_eff, product keyword QC.LIN.EFF)
Description: the effective non-linearity correction at the reference
level of 10000 (recipe default), see the
Detector monitoring recipes User Manual.
- Gain (QC1 database table uves_lingain, column gain, product keyword QC.GAIN)
Description: The gain computed by the Photon Transfer Curve method
(PTC), see the
Detector monitoring recipes User Manual.
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Modes
DARK frames (CATG = CALIB, TYPE = DARK, TECH = IMAGE) are measured
occasionally, for the BLUE and RED arms separately, with the shutter
closed. They are used to measure the dark current. They come
in 1x1 and 2x2 binnings. They have typical exposure times of 1 hr.
 There
are also DARKs with short exposure times, typically 60 secs. These are used
for CCD cleanup and are useless for monitoring the dark current.
QC1 parameters
Dark current. The UVES pipeline generates master DARKs
from input raw DARKs. A master BIAS is subtracted. The mean of the
residual pixels is calculated and transformed into the dark current.
Usually results from the 1x1 darks are unreliable since the dark
current is actually very low. Hence all numbers given here are for
the 2x2 bin mode. They are in units of [ADU/hr/4px]. The transformed
values in electrons per hour have used the conversion factors 0.60
electrons per ADU for the blue, and 0.52 electrons per ADU for the
red CCDs.
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