Monitoring the HARPS Detector Performance

In June 2003 we started a monitoring programme for the HARPS detector. Currently we regularly measure the conversion factor/gain of both chips comprising the detector mosaic.

The following page resumes the most relevant CCD measurements for all CCDs used at the 3.6m telescope, including the HARPS ones (77 and 78): 3.6m metrics.

Here are the latest data for chip # 77 and # 78


*** MIDAS logfile (03SEPpl1.2) *** Mo, 01 Nov 2004   12:38:46   Page 1
 
 
*** MIDAS logfile (vers. 03SEPpl1.2) *** Mo, 01 Nov 2004   12:39:19   Page 2
 
     ==========================================================
     SUMMARY STANDARD TEST CCD#77 TAKEN ON 041101 IN F417 MODE
     ==========================================================
 
      BIAS
      ====
 
      5 biases at start test: average = 286.54 stddev =   3.55
 
      There were 0 hot pixels/columns detected
 
 
      TRANSFER FUNCTION AND LINEARITY DATA
      ====================================
 
  Table : Std_F417_77_041101 
 Sequence Exp_tim1  Med_cnt1  Med_cnt2  Variance  Frc_cnt1  Frc_cnt2  el_adu1  
 -------- --------- --------- --------- --------- --------- --------- ---------
        1      3.18    4470.6    4488.5    2902.4     -8.60     -8.06      1.54
        2      6.34   10083.3   10098.6    7275.6      3.23      3.58      1.39
        3      9.49   14163.5   12675.2    9333.7     -3.29    -13.28      1.52
        4     12.65   18433.5   20109.4   14209.4     -5.58      3.21      1.30
        5     15.81   24547.9   24655.2   17704.2      0.62      1.25      1.39
        6     18.97   29905.3   30038.0   21438.1      2.16      2.81      1.39
        7     22.12   35396.8   35557.1   26005.9      3.65      4.32      1.36
        8     25.28   39566.9   38169.0   28154.6      1.38     -2.01      1.41
        9     28.44   46526.8   46730.5   33940.1      5.97      6.64      1.37
       10     31.60   49006.0   49447.5   34900.2      0.46      1.56      1.40
 -------- --------- --------- --------- --------- --------- --------- ---------
 
      Dynamic range explored: from 6188 to 68003 e-
      Average count rate measured: 1543 ADU/sec.
 
      CONV. FACTOR AND RON
      ====================
 
      C.Fact =   1.38 +/-   0.02 e-/ADU
 
      RON    =   4.90 +/-   0.07 e- RMS
 
 
      SHUTTER ERROR
      =============
 
 Average shutter error derived from fractional count rate = -0.010 sec
 
 
      LINEARITY ERROR
      ===============
 
 Average linearity error after shutter correct. = + 6.31/-10.94 %
 
 These errors represent maximum deviation in % from the average
 count rate after correction for shutter delay
*** MIDAS logfile (03SEPpl1.2) *** Mo, 01 Nov 2004   12:39:25   Page 1
 
 
*** MIDAS logfile (vers. 03SEPpl1.2) *** Mo, 01 Nov 2004   12:39:57   Page 2
 
     ==========================================================
     SUMMARY STANDARD TEST CCD#78 TAKEN ON 041101 IN F417 MODE
     ==========================================================
 
      BIAS
      ====
 
      5 biases at start test: average = 217.58 stddev =   3.65
 
      There were 0 hot pixels/columns detected
 
 
      TRANSFER FUNCTION AND LINEARITY DATA
      ====================================
 
  Table : Std_F417_78_041101 
 Sequence Exp_tim1  Med_cnt1  Med_cnt2  Variance  Frc_cnt1  Frc_cnt2  el_adu1  
 -------- --------- --------- --------- --------- --------- --------- ---------
        1      3.18    5603.8    5620.7    4315.4     -1.02     -0.14      1.30
        2      6.34   11402.7   11407.1    8791.9      0.85      1.48      1.30
        3      9.49   16974.8   15181.7   12399.7      0.14     -9.92      1.37
        4     12.65   20993.9   22819.6   16668.7     -7.09      1.58      1.26
        5     15.81   28467.5   28483.2   21237.1      0.81      1.45      1.34
        6     18.97   34252.4   34268.6   25430.0      1.08      1.72      1.35
        7     22.12   40059.4   40079.5   29621.7      1.34      1.98      1.35
        8     25.28   45675.7   43879.7   32922.6      1.11     -2.30      1.39
        9     28.44   51697.8   51725.5   38098.4      1.73      2.38      1.36
       10     31.60   57061.3   57134.4   41823.9      1.06      1.78      1.36
 -------- --------- --------- --------- --------- --------- --------- ---------
 
      Dynamic range explored: from 7747 to 78817 e-
      Average count rate measured: 1782 ADU/sec.
 
      CONV. FACTOR AND RON
      ====================
 
      C.Fact =   1.38 +/-   0.02 e-/ADU
 
      RON    =   5.04 +/-   0.06 e- RMS
 
 
      SHUTTER ERROR
      =============
 
 Average shutter error derived from fractional count rate = -0.010 sec
 
 
      LINEARITY ERROR
      ===============
 
 Average linearity error after shutter correct. = + 2.05/-8.51 %
 
 These errors represent maximum deviation in % from the average
 count rate after correction for shutter delay


Archive information available:

  • /sci/facilities/lasilla/sciops/3p6/CCDs/HARPS contains the listings produced by the MIDAS script used for performing the test. The file names give the information needed to access the desired information: Std_F<readspeed>_<chipnumber>_<yymmdd>.txt. These are ascii files. Chip number 77 is Linda, the "blue" chip, chip number 78 is Jasmin, the "red" chip.
  • /sci/facilities/lasilla/sciops/CCDs/HARPS/plots contains postscript plots generated by the same script. The file naming convention is sililar as abov: Std_F<readspeed>_<chipnumber>_<yymmdd>_<plottype>.ps.

In case you need further information, please contact harps@eso.org.