Diamond Microdosimeters and Microdetectors

Diamond displays many attractive properties which make it an ideal material both for nuclear particle detection and for X-ray dosimetry in medical fields. In fact diamond is radiation hard, tissue equivalent and compatible, and by using CVD (Chemical Vapour Deposition) it can be deposited on different substrates and in different shapes. We have fabricated CVD diamond microdosimeters by depositing thin diamond films (< 20 um thick) on tungsten wires and tips with diameters ranging f rom 50 um to 300 um. Tips shape can be easily controlled by electrochemical etching the W wire, from emispherical to almost conical one. The electrodes are arranged in a coaxial geometry. These devices can both detect alpha particles, protons and ions with a reasonable energy resolution and with bias voltages of the order of 50 V and can be used as X-ray microdosimeters in small field radiotherapy planning, with an extremely good spatial resolution. We have recorded the performances and the homogeneity of the response of these detectors with proton and alpha particles microbeams by IBICC (Ion Beam Induced Charge Collection) and we have measured the exact dose rate profile of small X-r ay beams with an unprecedented spatial resolution.