SEMICONDUCTOR DIODE MATRIX FOR ISOTOPE LOCALIZATION

A semiconductor matrix has been developed using lithium-drifted diodes, and successfully applied to two-dimensional radiation localization. It is based on the construction of an array of individual detection regions upon a single silicon diode by orthogonal partitioning of the p and n regions. In the matrix formation, parallel grooves, 0.5 mm wide, were cut into both the p and n faces of a silicon diode, penetrating the intrinsic region. The measured resistance achieved across all grooves is at least 109 ohms, as a result of chemical etching and surface treatment. The isolation of the electrode regions bounded by the grooves on the p and n sides of the device permits row and column addressing of charge pulses from ionizing radiations. By interconnecting the rows and interconnecting the columns of a number of such units, larger areas can be monitored. A resolution of (3*3) mm has been achieved. The configuration is considered suitable for the construction of a gamma camera.