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EUROPEAN SOUTHERN OBSERVATORY
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![[ MPG/ESO-2.20m ]](/lasilla/images/2p2_tn.jpg)
| CCD#60 with FIERA Controller in readout mode 225kHz,1,low (norm).Blue LED (LAMP7) Light Source |
General Information
Since November 2003 the CCD camera has been operated with an ESO standard FIERA CCD controller. The FIERA controller is capable of delivering the full performance of the CCD in terms of readout noise, CTE, immunity from interference, crosstalk, etc., and provides the image files with the necessary header information. Typical ReadOut Times (ROT), ReadOut Noise (RON) and Conversion Factors (CF, i.e. inverse Gain) characteristics, for the three defined readout modes are given in table 1.
| CCD Characteristics | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| ReadOut Mode | CF [e-/ADU] | RON [e-] | ROT [s] | Dark Curr [e-/pix/hr] | CTE [par/ser] | Linearity [%] | Full Well Cap. [e-] | Num Ports | Purpose |
| 225kHz,1,low (norm) | 3.2 | 5.1 | 41 | TBD | TBD | TBD | 150,000 | 1 | For High S/n Observations |
| 60kHz,1,high (slow) | 1.0 | 3.0 | 148 | TBD | TBD | TBD | 150,000 | 1 | For faint, RON-limited sources |
| 625kHz,1,med (fast) | 2.7 | 7.2 | 21 | TBD | TBD | TBD | 150,000 | 1 | For fast-monitoring observations |
The performance figures given were derived in the initial characterisation tests performed when the CCD controller was chnaged from the previous BIAS system to the FIERA system in November 2003. This page provides a database of characteristics derived from regular monitoring of the CCD performance.
The camera uses an EEV CCD detector of the design specified for FEROS, i.e., 2048x4096 pixels of 15x15microns, mounted in a continuous-flow cryostat. The CCD can only be mounted with the columns in the main dispersion direction. The CCD is operated at a temperature of -135 degrees Celsius
The thinned 2kx4k CCD and the standard ESO-VLT continuous-flow cryostat are provided by ESO.
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.
![[Click here to download ps file]](ST_deri.gif)
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 (07SEPpl1.1) *** Mo, 09 Dec 2013 10:21:25 Page 1
*** MIDAS logfile (vers. 07SEPpl1.1) *** Mo, 09 Dec 2013 10:21:38 Page 2
============================================================
SUMMARY STANDARD TEST CCD#60 TAKEN ON 20131209T092420 IN norm MODE
============================================================
BIAS
====
5 biases at start test: average = 247.48 stddev = 1.68
There were 0 hot pixels/columns detected
TRANSFER FUNCTION AND LINEARITY DATA
====================================
Table : Std_norm_60_20131209T092420
Sequence Exp_tim1 Med_cnt1 Med_cnt2 Variance Frc_cnt1 Frc_cnt2 el_adu1
-------- --------- --------- --------- --------- --------- --------- ---------
1 7.89 1635.5 1635.9 602.7 0.10 0.11 2.71
2 15.77 3263.6 3263.5 1221.3 -0.10 -0.11 2.67
3 31.54 6523.9 6523.4 2416.4 -0.13 -0.14 2.70
4 47.30 9784.3 9786.8 29117.7 -0.14 -0.11 0.34
5 70.95 14684.1 14684.2 5305.8 -0.08 -0.08 2.77
6 94.60 19586.5 19586.2 7000.1 -0.04 -0.04 2.80
7 118.25 24500.0 24499.4 8712.4 0.03 0.03 2.81
8 157.66 32681.8 32680.5 11397.0 0.08 0.07 2.87
9 197.08 40887.6 40883.9 13944.7 0.16 0.15 2.93
10 236.49 49042.3 49047.2 16388.7 0.12 0.13 2.99
-------- --------- --------- --------- --------- --------- --------- ---------
Table : Std_norm_60_20131209T092420
Column # 5 Label :Med_cnt1
Total no. of entries : 10, selected no. of entries : 10
Minimum value : 1635.545 , Maximum value: 49042.30
Mean value : 20258.967 , Standard dev.: 16302.385
Table : Std_norm_60_20131209T092420
Column # 6 Label :Med_cnt2
Total no. of entries : 10, selected no. of entries : 10
Minimum value : 1635.884 , Maximum value: 49047.25
Mean value : 20259.115 , Standard dev.: 16302.529
Dynamic range explored: from 7334 to 219894 e-
Average count rate measured: 207 ADU/sec.
CONV. FACTOR AND RON
====================
C.Fact = 4.48 +/- 3.44 e-/ADU
RON = 7.55 +/- 5.78 e- RMS
SHUTTER ERROR
=============
Average shutter error derived from fractional count rate = -0.002 sec
LINEARITY ERROR
*** MIDAS logfile (07SEPpl1.1) *** Mo, 09 Dec 2013 10:21:38 Page 3
===============
Average linearity error after shutter correct. = + 0.16/-0.14 %
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:
| Column Number | Description |
|---|---|
| 1 | Average of the rows and cols. of the bias image |
| 2 | Combined bias frame of 5 bias images |
| 3 | Histogram of the bias image |
| 4 | Plots of exposure sequence, unedited transfer and raw linearity |
| 5 | Plots of filtered linearity and differential non-linearity in |
| 6 | Filtered transfer curves for both data sets |
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.
| Long Tests |
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| Updated: 09/Dec/2013 |
FEROS CCD Page |
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