  The charge collection properties of CVD diamond have been investigated with
ionising radiation. In this study two CVD diamond samples, prepared with
electrical contacts have been used as solid state ionisation chambers. The
diamonds have been studied with beta particles and 10 keV photons, providing a
homogeneous ionisation density and with protons and alpha particles which are
absorbed in a thin surface layer. For the latter case a strong decrease of the
signal as function of time is observed, which is attributed to polarisation
effects inside the diamond. Spatially resolved measurements with protons show a
large variation of the charge collection efficiency, whereas for photons and
minimum ionising particles the response is much more uniform and in the order
of 18%. These results indicate that the applicability of CVD diamond as a
position sensitive particle detector depends on the ionisation type and appears
to be promising for homogeneous ionisation densities as provided by
relativistic charged particles.
