First tests of a thin natural diamond detector as an energy spectrometer for low-energy heavy ions

Diamond is an attractive alternative to silicon as a heavy ion detector owing to its exceptional radiation hardness and very fast timing. These remarkable properties of diamond allow one to expect that diamond detectors can outperform silicon detectors and ionization chambers for many applications, in particularly, for heavy ion accelerator mass spectrometry (AMS) measurements. However, most reported diamond particle detectors have been based on polycrystalline chemical-vapor-deposited diamond films and exhibited poor energy resolution (due to loss of charge carriers in the grain boundaries) resulting in limited applications, primarily for counting ions at hundreds of MeV/u. In this paper the evaluation of a thin single-crystal natural diamond detector as an energy spectrometer for 13C, 180Hf, and 238U ions in the energy range from 12 to 38 MeV is presented. The influence of “priming” and “polarization” effects is discussed. Initial measurements of energy resolution, stability and radiation hardness of the natural diamond detector have demonstrated its suitability for heavy ion AMS, in spite of some technical problems to be solved.