Camera Housing

The camera housing provides a vacuum environment and shielding for the CCDs. A schematic drawing of the CUBIC CCD camera system is shown in Figure 8.

Each CCD is mechanically supported by a niobium block ( pure) bonded to its back. Nb was chosen in order to minimize the differential thermal expansion between the CD package and the mounting block. The Nb block is screwed down to an Al plate which is clamped to the top of the TEC. A thin piece of indium foil between the niobium mounting block and Al cold plate ensures good thermal contact between them. A platinum RTD mounted between the Nb mounting block and the CCD package monitors the temperature of each CCD, while AD590s monitor the temperature of the backside of the TEC and the camera housing.

The camera housing also provides radiation shielding for the CCDs. Although the CCDs we fly are relatively radiation hard, they will still be gradually damaged by radiation, primarily trapped protons [9]. We have incorporated as much shielding in the camera housing design as allowed by our mass budget. This includes 1.1 kg of 304 SS shielding added to the outside of the camera body during final assembly. In addition, the CCDs will be operated at the lowest temperature possible to ameliorate the effects of this damage.

The camera housing and most other payload components near the CCDs are constructed of aluminum to reduce background problems caused by activation of high Z materials.

Next ...
Table of Contents ...