Micro-IBICC and micro-IL analyses of CVD diamond microdosimeters E. Vittone a, * , C. Ricciardi a , A. Lo Giudice a , F. Fizzotti a , C. Manfredotti a , G. Egeni b , V. Rudello b a Experimental Physics Department, University of Torino, INFN-To, INFM-UniTo, via Pietro Giuria 1, 10125 Torino, Italy b LNL-INFN National Laboratory of Legnaro, Italy Abstract Diamond is an ideal material to fabricate dosimeters because it is tissue equivalent, chemically stable, non-toxic, mechanical and radiation hard. Chemical vapour deposition technique CVD) allows for the fabrication of small di- amond detectors, which can be considered for in vivo dose measurements. We have fabricated microdosimeters by depositing thin diamond ®lms <20 lm thick) on tungsten wires diameter below 300 lm). Such devices work as solid state ionisation chambers where the electrodes are the W substrate and 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 microdosimeters. The uniformity of the electronic quality of diamond has been evaluated by mapping the charge collection eciency as obtained by IBICC measurements, whereas IL was used to map radiative recombination centres as well as to study radiation damage eects. Finally, a synergetic combination of PIXE and IL maps allowed us to evaluate the shape of the diamond ®lm covering the W sub- strate. Ó 2001 Elsevier Science B.V. All rights reserved. PACS: 78.60.Hk; 78.70.-g; 72.20.Jv Keywords: Ionoluminescence IL); Ion beam-induced charge; X-ray dosimetry; CVD diamond 1. Introduction The interest in the use of diamond as a radia- tion dosimeter stems principally from its tissue equivalence, chemical stability, non-toxicity, me- chanical robustness and radiation hardness. Usu- ally, natural gems are used in commercial diamond detectors. The main drawbacks of these dosimeters are the high cost and long waiting time, due to the severe selection of gems with suitable quality [1]. The chemical vapour deposition technique CVD) is a suitable technique for the fabrication of syn- thetic diamond samples with electronic properties comparable to those of the much more expensive and rare ``detector grade'' natural diamonds. Since 1995, our group has been involved in the fabrication of position-sensitive and needle-shaped Nuclear Instruments and Methods in Physics Research B 181 2001) 349±353 www.elsevier.com/locate/nimb * Corresponding author. Tel. +39-11-67-07-317; fax +39-11- 66-91-104. E-mail address: vittone@to.infn.it E. Vittone). 0168-583X/01/$ - see front matter Ó 2001 Elsevier Science B.V. All rights reserved. PII:S0168-583X01)00527-4