2003 - Astronomia - Università degli Studi di Firenze

The rocket version of the Controller need to be much smaller of the current laboratory prototype;
therefore, the final version will not have the modular architecture in order to keep its dimensions as small
as possible and to fit the available space on the rocket. Currently, power supplies fill more than 50% of the
Controller volume; in the rocket version power supplies are external and common to all instruments,
therefore we expect at least to halve the Controller volume.
The Sequencer and the CD circuits provide the clocks to perform the charge flow inside the CCD; the
signals for the CDS signal processing and for the ADC conversion (Clamp & Sample, Start Convert) are still
generated by the Sequencer.
Vacuum flange
Multipolar
connectors
Cold finger
Three perspectives of the camera head
XUVLab activity summary 2003
Water-cooled
heat sink
Currently the camera head hosts the sensor and some proximity electronics such as the preamplifier and
the low pass filters for the CCD bias voltages and for the clock wave-shaping. In addition, it usually
comprises part of the cooling system: in this case a Thermo-Electric Cooler (TEC).
CCDs are used in astronomy mostly because of their sensitivity, large dynamic range and very low
readout noise. Therefore, the Controller readout electronics must be low-noised to match the CCD
performance. This is a crucial constraint for the preamplifier stage, because it is the first signal processor,
directly connected to the sensor output. The preamplifier is based on an original design developed for
very low-noise applications. A central module of the camera package supports the TEC that is a threestage
Peltier cooler. The module also hosts a water-cooled heat sink for the TEC. Currently, we control the
sensor temperature by means of a dedicated module in the Controller: we can digit the target
temperature and set a number of parameters, such as the output power and its temporal shape, the
alarm set-points, the tuning cycles.
Furthermore we realized an external portable closed-cycle cooling
system in order to cool the hot side of the main TEC.
detectors developements 18