Micro-IBICC and micro-IL analyses of CVD diamond microdosimeters

Diamond is an ideal material to fabricate dosimeters because it is tissue e quivalent, chemically stable, non-toxic, mechanical and radiation hard. Che mical vapour deposition technique (CVD) allows for the fabrication of small diamond detectors, which can be considered for in vivo dose measurements. We have fabricated microdosimeters by depositing thin diamond films (< 20 m um thick) on tungsten wires (diameter below 300 mum). Such devices work as solid state ionisation chambers where the electrodes are the W substrate an d a thin gold layer evaporated on the diamond surface. The ion beam-induced charge collection (IBICC) and ionoluminescence (IL) techniques turn out to be very suitable to characterise such small and irregularly shaped microdo simeters. The uniformity of the electronic quality of diamond has been eval uated by mapping the charge collection efficiency as obtained by IBICC meas urements, whereas IL was used to map radiative recombination centres as wel l as to study radiation damage effects. Finally, a synergetic combination o f PIXE and IL maps allowed us to evaluate the shape of the diamond film cov ering the W substrate. (C) 2001 Elsevier Science B.V. All rights reserved.