Charge coupled devices (CCDs) - a detector system for particles with time resolution and local assignment with particle trajectories

The properties of Charge Couples Devices (CCDs) have been investigated with respect to the detection of charged particles. Using standard TV-techniques for reading the particle induced charge distribution in the pixel elements, these devices yield local information on the trajectory of particles with a resolution of 10 x 15 μm, and the linear energy transfer (LET). A linear response is expected for particles with LET between that of relativistic protons and relativistic iron ions. For particles with higher LET irreversible damage of single pixel elements has been observed. In the low LET region the CCD elements can be used as local and time resolving active detectors with a fast continuous electronic read out, whereas in the high LET region permanent damage is accumulated, as in other passive particle track detectors, for off-line evaluation. Examples of the application of CCDs in the field of radiobiology are discussed. (author)