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VLT-MAN-ESO-14650-4942
P96
24.06.2015
37 of 161
ESO, Karl-Schwarzschild-Str. 2, 85748 Garching bei München, Germany
2.2.4.3 Detector
The UVB detector is a 2048
4102, 15µm pixel CCD from E2V (type CCD44-82) of which
only a 1800
3000 pixels window is used. The CCD cryostat is attached to the camera with
the last optical element acting as a window. The operating temperature is 153K. The CCD
control system is a standard ESO FIERA controller shared with the VIS CCD. The list of
readout modes offered for science observations is given in Table 5.
One more readout mode (1000
1000 window, low gain, fast readout, 1x1 binning)
exclusively used for flexure measurement and engineering purposes is also implemented.
Measured properties and performances of this system are summarized in Table 6. The
associated shutter, located just after the slit is a 25mm bi-stable (2 coil, zero dissipation)
shutter from Uniblitz (type BDS 25). Full transit time is 13ms. Since the slit is 2.8mm high
(11” at f/6.5), the illumination of the detector is homogenous within <<10ms.
Table 5: List of detector readout modes offered for science observations. *The 2x2 binning is not
recommended whenever a good inter-order background subtraction is required (see also section
2.4.5).
Readout mode
Gain [e-/ADU]
Speed
Binning
name
UVB
VIS
[kpix/s] Spatial dir. Dispersion dir.
100k/1pt/hg
High
[0.62]
High
[0.595]
Slow
[100]
1
1
100k/1pt/hg/1x2
1
2
100k/1pt/hg/2x2*
2
2
400k/1pt/lg
Low
[1.75]
Low
[1.4]
Fast
[400]
1
1
400k/1pt/lg/1x2
1
2
400k/1pt/lg/2x2*
2
2