1. The silicon detector
2. 2D - simulation of the hole current flux in a gated punch-through biasing structure for silicon microstrip detectors
3. The piling of various detectors
4. Detail of the wire bonding region between the silicon detector and the Kapton cable
The unusual shape of the silicon detector which can be seen in this picture (fig.1) is the result of some years of development dedicated to applications of silicon sensors in the field of radiology.
The innovation consist in exposing the detector "edge on" to the X rays (the beam comes from the low side in the picture). In this way, efficiencies higher than 80% in the energy range for medical imaging can be reached.
The detectors developed for this application contain interesting innovations, all of which allowing a simple piling of various detectors (fig. 3) until the desired sensitive surface is obtained. In this application, the dimensions of each imaging pixel are given by the detector thickness and the strips pitch in the sensitive zone: 300 x 200 µm2 in this case. For this detector, a dedicated electronics has been developed (see CASTOR).
These detectors have been realized within the SYRMEP project, which aims to improve the techniques in radiology applied to mammography by making use of the monocromatic X ray beams prepared at Sincrotrone Elettra. This experiment is a collaboration between INFN and the University of Trieste.