2p2-m Telescope CCDs The DFOSC CCD Page
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General Information

The CCD currently in use with DFOSC at the Danish 1.54-m Telescope was provided by the Copenhagen University Observatory and is a backside illuminated LORAL/LESSER chip with 2052x2052 15 micron pixels and has an additional 100 pixel overscan in the X-direction. The current CCD (C1W7) has been in use at the telescope since April 25, 1997. Note: The CCD controller was changed Jan.14, 1999.

Reports on the CCD's properties

Derivatives

Standard CCD Test

Long CCD Test

Time Evolution

The below plot shows the variation of the bias level, standard light-source (note that often a beta-light is used which, due to radioactive decay, will fade. It is also possible that the phosphor can be poisoned, but our data show no evidence for such an effect), gain, read-out noise, shutter error, and linearity error as a function of time. The values for the bias, gain and read-out noise are plotted along with the associated measurement error. The blue dashed line in the plots shows the mean value of all the points, while the dotted blue line shows the standard deviation of this distribution. The blue and red points in the bottom plot show the maximum deviations in a positive and negative sense wrt the least-squares fit of the linearity data. Plotted vertically on the bottom of the graph is the date (dd/mm) on which the test was made.

For printing, the above plot is also available in postscript format . The raw data can also be viewed in a tabular format.

Standard CCD Test

Below we show the most recent test.

  ***  MIDAS logfile (vers. 95NOV) *** Tu, 12 Sep 2000   18:57:13   Page 1
 
 
  ***  MIDAS logfile (vers. 95NOV) *** Tu, 12 Sep 2000   18:58:35   Page 2
 
     ========================================================== 
     SUMMARY STANDARD TEST CCD#01 TAKEN ON 000912 IN fast MODE 
     ========================================================== 
  
      BIAS 
      ==== 
  
      5 biases at start test: average = 1222.35  stddev =   6.44  
  
      There were 0 hot pixels/columns detected 
  
  
      TRANSFER FUNCTION AND LINEARITY DATA 
      ==================================== 
  
  Table : Std_fast_01_000912 
 Sequence Exp_tim1  Med_cnt1  Med_cnt2  Variance  Frc_cnt1  Frc_cnt2  el_adu1  
 -------- --------- --------- --------- --------- --------- --------- ---------
        1      1.00    1199.3    1200.3     923.7     -0.03      0.06      1.30
        2      2.00    2394.1    2393.1    1786.6      0.08      0.04      1.34
        3      3.00    3583.3    3583.0    2671.2     -0.04     -0.05      1.34
        4      6.00    7161.0    7159.0    5245.2     -0.02     -0.05      1.37
        5      9.00   10734.1   10734.2    7964.8     -0.05     -0.05      1.35
        6     12.00   14311.6   14310.9   10351.7     -0.04     -0.05      1.38
        7     17.00   20272.3   20273.6   14791.9     -0.04     -0.03      1.37
        8     27.00   32210.0   32206.5   22992.8      0.01      0.00      1.40
        9     37.00   44151.7   44151.6   31453.5      0.05      0.05      1.40
       10     44.00   52519.9   52521.0   37788.8      0.08      0.08      1.39
 -------- --------- --------- --------- --------- --------- --------- ---------
  
      Dynamic range explored: from 1681 to 73573 e- 
      Average count rate measured: 1193 ADU/sec. 
  
      CONV. FACTOR AND RON 
      ==================== 
  
      C.Fact =   1.40  +/-   0.00  e-/ADU 
  
      RON    =   9.03  +/-   0.03  e- RMS 
  
  
      SHUTTER ERROR 
      ============= 
  
 Average shutter error derived from fractional count rate =  0.006  sec 
  
  
      LINEARITY ERROR 
      =============== 
  
 Average linearity error after shutter correct. = + 0.08 /-0.05  % 
  
 These errors represent maximum deviation in % from the average 
 count rate after correction for shutter delay 

In addition, the previous standard tests are available. Click in the table below to access these files.

In the above table, the postscript files are:

Note: filtered means that saturated images or deviating too much from the other data, if present, have been removed.

Long CCD Test

Below are the results of the long tests carried out by ODT. Be warned that these are large compressed tar files, and are of specialised interest. To download, press the shift key and click on the hypertext link with your middle mouse button.

Send comments to <epompei@eso.org> Last update: Nov 11, 2002