Detectors
PANIC will use a mosaic of four 2k x 2k HAWAII-2RG arrays from Rockwell (now Teledyne) in order to cover a field of view of approximately 30 arcmin.
The selection of the science detector was mostly based on cost, availability, and of course technical requirements. There were 3 options investigated: the 2K x 2K VIRGO detector from Raytheon, the 4K x 4K new development from Teledyne, and a mosaic of four HAWAII-2RG detectors also from Teledyne.
The HAWAII-4RG, Teledyne’s new development, was discarded at an early stage of the project because of cost and risk. The capital cost of the project would have increased in approximately 0.4 MEuro, and the array was only at a design stage.
On the other hand, the VIRGO detector was more expensive than the HAWAII-2RG, and since MPIA has gained a lot of experience working with Teledyne detectors, it was decided to use a mosaic of four 2k x 2k HAWAII-2RG arrays. These arrays were also preferred because they have a special “guide mode” in which a programmable window may be read out continuously at high pixel rates for stable tracking of guide stars, allowing interleaved readout with the full frame science data.
The science detectors are mounted into a molybdenum mosaic assembly plate. This mosaic integrates four HAWAII-2RG arrays as separate modules into one single thermal and vibration stable structure allowing precision alignment and physical flatness between all 4 detectors. The following figure shows a picture of the detectors mounted into the mosaic package, followed by a table with the major characteristics of these detectors.
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Parameter |
Specification |
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Total pixels |
2048 x 2048 |
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Pixel size |
18 µm |
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Physical Flatness |
± 40 µm PTV |
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Pixel readout rate |
100 kHz to 5 MHz |
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Output ports |
32 + 2 + “guide window” |
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Charge storage capacity |
> 100000 e- |
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Read noise (CDS) |
<=20 e- |
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Quantum efficiency |
>=75 % |
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Dark current |
< 0.1 e-/sec |
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Spectral range |
0.3 – 2.5 µm |
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Pixel operability |
>= 95 % |
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Operating temperature |
>= 65 K |
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Power dissipation |
<= 4 mW @ 100 kHz |
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Cost |
$ 350000 each |