We report on the response of metal-less CVD polycrystalline-diamond pixel sensors under -particles irradiation. A 21×21 array of 0.18×0.18 mm2 pixels was realized on one side of a 10.0×10.0×0.5 mm3 polycrystalline diamond substrate by means of laser induced surface graphitization. With the same technique, a large graphite contact, used for detector biasing, was fabricated on the opposite side. A coincidence detecting method was used with two other reference polycrystalline diamond detectors for triggering, instead of commonly used scintillators, positioned in the front and on the back of the sensor-array with respect to the impinging particles trajectory. The collected charge distribution at each pixel was analyzed as a function of the applied bias. No change in the pulse height distribution was recorded by inverting the bias voltage polarity, denoting contacts ohmicity and symmetry. A fairly good pixel response uniformity was obtained: the collected charge most probable value saturates for all the pixels at an electric field strength of about ±0.6 V/μm. Under saturation condition, the average collected charge was equal to <Qcoll> = 1.64 ± 0.02 fC, implying a charge collection distance of about 285 m. A similar result, within 2%, was also obtained for 400 MeV electrons at beam test facility at INFN Frascati National Laboratory. Experimental results highlighted that more than 84% of impinging particles involved only one pixel, with no significant observed cross-talk effects.

Komlenok, M., Bolshakov, A., Ralchenko, V., Konov, V., Conte, G., Girolami, M., et al. (2016). Diamond detectors with laser induced surface graphite electrodes. NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH. SECTION A, ACCELERATORS, SPECTROMETERS, DETECTORS AND ASSOCIATED EQUIPMENT, 837, 136-142.

Diamond detectors with laser induced surface graphite electrodes

CONTE, Gennaro
;
2016

Abstract

We report on the response of metal-less CVD polycrystalline-diamond pixel sensors under -particles irradiation. A 21×21 array of 0.18×0.18 mm2 pixels was realized on one side of a 10.0×10.0×0.5 mm3 polycrystalline diamond substrate by means of laser induced surface graphitization. With the same technique, a large graphite contact, used for detector biasing, was fabricated on the opposite side. A coincidence detecting method was used with two other reference polycrystalline diamond detectors for triggering, instead of commonly used scintillators, positioned in the front and on the back of the sensor-array with respect to the impinging particles trajectory. The collected charge distribution at each pixel was analyzed as a function of the applied bias. No change in the pulse height distribution was recorded by inverting the bias voltage polarity, denoting contacts ohmicity and symmetry. A fairly good pixel response uniformity was obtained: the collected charge most probable value saturates for all the pixels at an electric field strength of about ±0.6 V/μm. Under saturation condition, the average collected charge was equal to = 1.64 ± 0.02 fC, implying a charge collection distance of about 285 m. A similar result, within 2%, was also obtained for 400 MeV electrons at beam test facility at INFN Frascati National Laboratory. Experimental results highlighted that more than 84% of impinging particles involved only one pixel, with no significant observed cross-talk effects.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11590/303416
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