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FORS2 Quality Control:
Dark Current

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  CURRENT HISTORY
dark current (until 2002-03)
dark current (since 2002-04)
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   Click on CURRENT to see the current (last) trending (Health Check).
   Click on HISTORY to see the historical evolution of the trending.


top Dark Current

QC1 parameters

  • dark current averaged over frame (e-/px/hr) (QC1 database table fors2_dark, column dark_avg)
    This is the median level of the master dark, normalized per pixel and hour and converted into electrons.
  • error of average dark current (e-/px/hr) (QC1 database table fors2_dark, column sigma_dark_avg)
    As the error of the dark current is dominated by the read-out noise, it is calculated from the read-out noise provided in the header, scaled with the exposure time (as it is normalized to 1 hour).

History

For the old CCD (in use until March 22, 2002) the dark current was computed from the median master dark frame level in ADU/hr/px and transformed into electrons by using the conversion factor CONAD (in the case of 4 port readout a mean CONAD was used). Also the dark current per port was calculated and stored in the QC1 Database (dark_A(BCD), sigma_dark_A(BCD)).

The high DARK values observed after January 2008 are due to pickup noise according to Thomas Szeifert (statement from May 3rd, 2008).


 
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