The AAOmega
spectrograph will use EEV 4482 2kx4k CCD detectors with 15 micron pixels, with
each camera having an optimized blue or red detector.
The 2k x 4k format will allow ~10 pixels per fibre sampling (400 fibres in
4000 pixels) in
multiple-object mode, lowering fibre-to-fibre
cross talk and providing enough detector area for nod&shuffle observing
("minishuffling" into the gaps between spectra).
In IFU mode the sampling will be approximately 8 pixels per fibre
(512 IFU fibres in 4000 pixels).
Table 1 gives the specs of the EEV blue/red CCDs (note that these have
been taken from EEV, and some items
may change once the devices are characterized
by the AAO).
| AAOmega EEV CCDs
|
|
| Number of Pixels |
2048 x 4096 |
| Pixel Size |
15 micron |
| Read Noise (Blue/Red) |
2.8/2.2 electrons |
| Peak QE (Blue/Red) |
87/91%
|
Quantum efficiency curves of the current 2dF/Tek 1kx1k CCDs, and the
AAOmega EEV 2kx4k CCDs are compared in Fig. 1. Note the large
gains in QE in going from the Tek to the EEV CCDs, and the optimization
of the EEV CCDs for the AAOmega blue and red arms.
