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Detector Characteristics (ESPaDOnS)

GRACES is using the ESPaDOnS detector array, which consists of a 2kx4.5k deep-depletion e2v device called Olapa. The table below gives a summary of the current detector/controller characteristics (note that the ESPaDOnS' detector webpage is out of date and describe a decommissioned detector).

 Array  e2v device Olapa
 Pixel format  2080x4640
 Pixel size  13.5 μm square
 Spectral response  ~0.34 to 1.03 μm
 Bias level  Bias image
     Flat field response      Flatfield image
 Readout time       See observing overheads page     
 Dark current  0.0126 é/pix/h
 Saturation level  65,535 ADU
 Non-linearity  0.4% at 46,400 ADU


Readnoise and Gain Values

The table below gives the gain/read-noise values for the ESPaDOnS CCDs. 

 Readout mode   Gain (é/ADU)    Noise (é)    Read time (s) Recommanded for ... 
 Fast*  1.6  4.7 32
 S/N (per frame) > 100
 Normal  1.3  4.2 38  40 < S/N (per frame) < 100 
 Slow  1.2  2.9 60  S/N (per frame) < 40

* FAST readout mode is not supported at Gemini. Please contact the GRACES team ( if you were planing to using it.