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GMOS-N array

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The original GMOS-N detector array consisted of three 2048x4608 EEV chips arranged in a row. This array was replaced by e2v deep depletion devices in October 2011.

The table below gives a summary of the original EEV detector/controller characteristics.

Array EEV
Pixel format 6144x4608 pixels
Array layout Three 2048x4608 chips in a row with ~0.5mm gaps
Pixel size 13.5 microns square; 0.0727 arcsec/pixel
Spectral Response approx 0.36 to 0.94 microns [ data / plot ]
Bias level Bias image
Flat field response Fringe images  Flat field images
Readout time See observing overheads page
Chip CCD 01 CCD 02 CCD 03
Chip ref no. EEV 9273-16-03 EEV 9273-20-04 EEV 9273-20-03
Dark current* 0.8 e-/pix/hr 0.7 e-/pix/hr 0.5 e-/pix/hr
Full Well ** 150 ke- 101 ke- 159 ke-
Fringing at 900nm *** 29% 19% 24%

* Dark current measured at -120C by NOAO
** Saturation can be avoided by assuming 100ke- for all chips
*** (peak-valley)/mean, measured from images taken at NOAO

Readnoise and Gain Values

The table below gives gain/read-noise values for the original GMOS-N EEV CCDs operating with the SDSU controller. Only the suggested settings are listed. The values are averaged over all 6 amps. For the full table of read-noise and gain values at all settings and for all amps, click here.

Readout Gain Resulting average
rate level Gain (e-/DN) noise (e- rms)
Fast High 5.02 7.4
" Low 2.49 4.9
Slow High 4.40 4.8
" Low 2.18 3.4