Temporally resolved response of a natural type IIA diamond detector to single-particle excitation

Abstract

We have measured the response of natural type IIa diamonds to single-particle excitations. Not only do the rise and fall times of pulses decrease as a function of increasing bias, but also the shape of the pulse tails changes from approximately exponential to approximately gaussian in form. Over the range of electric fields between 10 4 and 10 5 V cm −1, rise times are less than 50 ps and fall times approach the carrier transit times across the detector as saturation velocities are approached. A temporally and spatially dependent carrier transport model has been used to interpret the experimental results. To perform these measurements, natural type IIa diamonds were incorporated into 50 Щ stripline structures which were coupled to a high bandwidth recording system. The system rise time was measured to be 18.6 ± 1.8 ps. The detectors were excited with heavy charged particles accelerated with a tandem electrostatic accelerator. At low fields, bulk recombination appears to dominate the fall times. Results at higher fields suggest that the contacts are non-injecting. Incomplete charge collection is clearly seen, even at the highest electric field, which implies that the trapping-recombination dynamics play a significant role in the charge collection process.