Paper 2003-01
Blue
light sensitization of CVD diamond detectors
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Diamond and Related Materials 12 (2003)
662-666 |
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C. Manfredotti*1,2,
E. Vittone1,2, C. Paolini1,2, P.Olivero1,2, A. Lo Giudice2 |
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1 Experimental Physics Department, University of Torino,
Torino, Ital, and INFN, sez. Torino. 2 INFM
(National Institute for Matter Physics), UdR Torino-University, Torino, Italy |
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Keywords: Diamond film, detectors, plasma CVD, optical
properties, electrical properties |
Abstract
CVD diamond needs to be “primed” or “pumped” by x-rays or by high energy
electrons in order to be qualified for nuclear detection. In this “pumped”
state, CVD diamond detector performances are reported to be more reproducible,
homogeneous and averagely better. The pumping effect is usually attributed to
filling of ( hole ) traps, which are
responsible for the charge collection efficiency of the detector.
In this work, the possibility of filling traps selectively by light has been systematically investigated,
in order to find the kind of “background light” in which the detectors could
preserve their performances
indefinitely in time.
Irradiation by the blue light before or/and during the detection of
nuclear particles seems to avoiding the large doses needed for pumping. Other
wavelengths seem to be totally inefficient from this point of view. It turns
out that electrons are responsible for charge transport during blue light
priming, while holes give the largest contribution during x-ray priming. The
results will be presented as maps of charge collection efficiency in CVD
diamond detectors as obtained by IBIC (Ion Beam Induced Charge) carried out by
using a proton microbeam.