The structure of the instrument consists of two parts: the electronic box, containing 3 boards and the sensor head with the two telescopes, one telescope containing one pair of detectors. Each PIPS (Passivated Implanted Planer Silicon) detector consists of one centre segment surrounded by a cross-talk ring and a guard ring and is 300 μm thick.

Figure 2: On the left, a 3-D view of one SEPT unit with its open protection covers. On the right, detailed view of the SEPT showing the structure of the sensor head and the 3 boards, from top to bottom: analogue/EMI shied/digital (Drawings courtesy Uni. of Kiel)

	Introduction
	Electronics