N. Mirizzi

Preliminary study on polycrystalline diamond films suitable for radiation detection

The microwave plasma enhanced chemical vapor deposition technique has been employed to grow polycrystalline diamond films on p-doped Si (100) substrates starting from highly diluted (1% CH4 in H2) gas mixtures. Coplanar interdigitated Cr/Au contacts have been thermally evaporated on two samples about 8 µm thick having different grain size. Dark current-voltage (I–V) measurements and impedance characterization have been found to be dependent on the grain size and on the quality of the examined samples.

Transition radiation detectors: state of art and new developments

Transition radiation (TR) is emitted whenever a fast particle (γ > 1000) crosses the boundaries of a periodic structure. Since the prediction of this effect, many studies and tests have been accomplished to understand both the features of this radiation and the eventual practical applications. Nowadays. the main application of TR is particle identification in accelerator physics and astrophysics. Particle identification is one of the most challenging aspect of the experiments performed in these fields. In fact the experimental problems arisen in the recent accelerator physics pose stringent constraints on the detectors due to the high rates, severe background conditions, event final state complexity. On the other hand, the cosmic ray physics requires in some cases simple but refined and reliable devices to be used in outer space or otherwise huge and stable apparata for surface and underground laboratories. After a brief presentation of the TR phenomenon produced by ultrarelativistic particles and relative detectors, the state of the art of this particle identification technique relative to the more recent TRDs will be discussed.