Use of high-sensitivity diamond detectors in DC mode for detailed beam-profile measurements in particle accelerators

Abstract

Because of its high radiation hardness, diamond can be used better than other materials in the intense radiation field characterizing the interior region of a particle beam in an accelerator. In effect, the measurements reported here were carried out by placing diamond detectors under continuous irradiation in the 26-MeV proton beam of the 15-MV TANDEM accelerator of Southern National Laboratory (LNS) of INFN in Catania. The diamond detectors were built in the Rome Tor Vergata Laboratory. Diamond films were deposited by microwave plasma enhanced chemical vapor deposition on silicon substrates. A four-pixel beam monitor prototype was then realized by depositing four titanium gold contacts on the diamond surface. The signal was found to be stable and reproducible. The collected charge in DC mode was more than 20 000 electrons/protons for a diamond thickness of 65 μm, thus exhibiting a gain of approximately 10 4 with respect to the Faraday cup. For the measured samples, both response and release times of approximately 1 s were observed in the above experimental conditions. An analysis of the relative sensitivity between pixels was also performed. No differences of the detector current and Faraday cup current ratio were observed for different pixels, indicating the homogeneity of the beam monitor response.