Recent Results from CVD-Diamond Heavy-Ion Detectors

Latest results from radiation hardness measurements as well as single-particle pulse shape parameters, pulse-height distributions and time spectra are presented. An intrinsic time resolution of 29 ps is achieved with 52Cr ions of 650 MeV/amu and of 53 ps with 12C ions of 1.5 GeV/amu, respectively. The resolution is by 20% worse when increasing the beam intensity from 106 ions/s to 108 ions/s. Performing 58Ni fragmentation, collected charge distributions are measured in the range 15 < Z < 28. Whereas the S/N ratio improves about a factor of 2 the width of all spectra obtained is 70%. The same behaviour is found in 241Am-αdistributions increasing the electric field applied to the detector. In order to visualize and to quantify the influence of the electric field as well as of the total particle fluence to the charge-collection efficiency micro-beam measurements are performed with 12C ions of 5.9 MeV/amu stopped in the diamond bulk. Pulse-height spectra and charge-collection maps under different conditions are discussed.