Timing Properties of CVD-Diamond Detectors at RelativisticVelocities*

In order to investigate the behaviour of Single-Crystal CVD-Diamond Detectors (SC-DD) at relativistic ion velocities, we measured original TC Signals (TCS) induced by Xe ions of 215AMeV in a SC-DD of a thickness dD =400μm and a capacitance CD=0.9pF. At a rate of 1.6kHz, a charge QG Xe =1.2*10 8 e-h pairs/ion was generated in the diamond bulk. We present a data discussion according to the theory of Space-Charge Limited Current transients (SCLC) [1], expected for QG > QBI, with QBI =CD*VD the bias-induced charge at the electrodes of the sensor. The Xe pulses were recorded with a 1GHz DSO of 10GS/s resolution, connected to the diamond via a highfrequency transmission line of 30m lengths. We compare the shapes of the Xe transients with α-signals measured in the laboratory using a broadband amplifier and a 3GHz DSO. Each α-particle generates a charge of QG = 4.2*10 e-h pairs within the α-range of 12μm, and represents the ‘small-signal case’ at ‘single-carrier drift’. Figure 1 shows average Xe transients obtained in the bias range 10V≤ |VD| ≤ 800V (solid and dotted lines) and an average α-signal (dashed line) measured at VD=800V. Note, the α-amplitude is magnified by an arbitrary factor.