The camera: geometry and mechanics

The camera is the sensitive component of the telescope. It is an array of 440 pixels arranged in a matrix of 22 rows and 20 columns with a field view of 30 x 28.6 degees (hor x vert). The actual focal surface of the telescope is spherical in shape and therefore the pixel matrix is adapted to this spherical surface. In practice the camera is realized by a strong aluminium body with 440 round holes to allocate the PMTs.
The shape of each pixel is hexagonal and the PMTs are also hexagonal. This ensures the best coverage of the sensitive area. The pixel side to side distance is 45.6 mm corresponding to an angular separation of 1.5 degree. Light falling on the small but not negligible insensitive region between adjacent PMTs is rescued by light collectors. The overall system has very good uniformity in the light collection efficiency at the level of few per cent.

Front view of the camera body

The camera body mounted on its support.

The system was designed by Guido Raia in Catania

The camera with 100 PMTs mounted in the left upper quadrant

The back side of the camera showing the head electronics mounted on the PMTs, the cables and a distribution board

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