Diamond is a resilient material with rather extreme electronic properties.
As such it is an interesting candidate for the fabrication of high performa
nce solid state particle detectors. However, the commercially accessible fo
rm of diamond, grown by chemical vapour deposition (CVD) methods, is polycr
ystalline in nature and often displays rather poor electrical characteristi
cs. This paper considers the way that this material may be used to form alp
ha particle dosimeters with useful performance levels. One approach adopted
has been to reduce the impurity levels within the feed-stock gases that ar
e used to grow the diamond films. This has enabled significant improvements
to be achieved in the mean carrier drift distance within the films leading
alpha detectors with up to 40% collection efficiencies. An alternative app
roach explored is the use of planar device geometry whereby charge collecti
on is limited to the top surface of the diamond which comprises higher qual
ity material than the bulk of the film. This has lead to collection efficie
ncies of greater than 70%, the highest yet reported for polycrystalline CVD
material based detectors. Techniques for improving the characteristics of
these devices further are discussed. (C) 1999 Elsevier Science S.A. All rig
hts reserved.