Large‐scale applications of silicon nuclear particle detectors have been developed during the recent decade for elementary particle physics experiments and for space‐based systems dedicated to studies of cosmic radiation. These detectors typically consist of arrays of highly segmented sensors with matching integrated circuit chips for the processing of the electric signals. Some of these systems cover an area exceeding 100 m
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with millions of sensor cells. In the past, the strong point of semiconductor detectors was their capability to measure with high precision the energy of ionizing particles in a small volume. Now these radiation detector systems, in addition, perform imaging functions that allow the reconstruction in space and time of radiation‐emitting objects and processes or elementary particle interactions. The imaging detectors also begin to find applications in materials analysis at synchrotron light sources and in some types of industrial equipment. The basic principles are briefly described and a few examples are discussed. The emphasis is on the instruments and reasons for their development are indicated, and brief particulars are provided here about the significant results that they have enabled.