The radiation hardness of high grade silicon detectors is summarized in ter
ms of an increase of the diode reverse current, evolution of the full deple
tion voltage and charge collection efficiency. With the aim of improving th
eir radiation tolerance, detectors have been produced from non-standard, fl
oat-zone silicon containing various atomic impurities and from epitaxial si
licon materials. Some recent results concerning their radiation hardness ar
e presented. (C) 1999 Elsevier Science B.V. All rights reserved.