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Quality Control and
Data Processing

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Trending & QC1
   detector monitoring
MUSE ...
QC links:
MUSE: Detector monitoring
Gain averaged
Gain per detector
QC1 database (advanced users): browse | plot


The gain value is calculated by the generic detmon recipe specially modified for MUSE purposes (considers different defined regions on the detector corresponding to 4 quadrants - read-out ports).


FITS key QC1 database: table, name definition class* HC_plot** more docu
QC.REG1.GAIN muse_detmon..reg1_gain GAIN value in region1 (see QC.REG1.METHOD) [ADU/el] HC [docuSys coming]
QC.REG2.GAIN muse_detmon..reg2_gain GAIN value in region2 (see QC.REG2.METHOD) [ADU/el] HC [docuSys coming]
QC.REG2.GAIN muse_detmon..reg3_gain GAIN value in region3 (see QC.REG3.METHOD) [ADU/el] HC [docuSys coming]
QC.REG4.GAIN muse_detmon..reg4_gain GAIN value in region4 (see QC.REG4.METHOD) [ADU/el] HC [docuSys coming]
*Class: KPI - instrument performance; HC - instrument health; CAL - calibration quality; ENG - engineering parameter
**There might be more than one.


Average gain and its rms is trended for 4 different defined regions on the detector, one per each quadrant (read-out port).

The selected region coordinates are ( llx,lly,urx,ury):

  • region1: 1933,565,1999,2065
  • region2: 2242,565,2308,2065
  • region3: 2242,2164,2308,3664
  • region4: 1933,2164,1999,3664

Data are taken about once a month with the instrumental mode (INS.MODE) ENGINEERING or NFM-AO-N, and the read-out mode (DET.READ.CURNAME) SCI1.0.

Scoring&thresholds Gain

The gain is very stable on the long term. It is scored tightly, with fixed values.


Date event
February 2014 data started being taken regularly
March 18, 2015 Flat lamps exchanged; new lamp gives higher flux; possible occasional saturation
March 23, 2015 Some test with a different and none standard binning (1x4) done at Paranal
2015-03-31 CHAN01 detector vessel exchanged, DET.CHIP.ID changed from psyche to egeria
2015-10-31 After intervention (detectors warmed up and vacuum recreated in the transfer lines) parameters back to normal; Most quadrants below 1% maximum relative nonlinearity; PPRS-063339
2018-02-20 Template updated; the flats' integration times were adjusted to probe wider flux range

Algorithm Gain

There are two exposures for each exposure time value of the flat-field sequence. Also, bias frames are taken at the beginning of the template. The following equation is calculated for each pair:

mean(flat1) + mean(flat2) - 2 * mean_bias = gain * [sigma^2(flat2-flat1)-sigma^2(bias2-bias1)] .

Following the Photon Transfer Curve (PTC) method, the final gain value is calculated from a linear fit to the above equation. The gain is expressed in ADU per electrons.

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