Radiation hard silicon detectors - developments by the RD48 (ROSE) collaboration

The RD48 (ROSE) collaboration has succeeded to develop radiation hard silic on detectors. capable to withstand the harsh hadron fluences in the trackin g areas of LHC experiments. In order to reach this objective, a defect engi neering technique was employed resulting in the development of Oxygen enric hed FZ silicon (DOFZ), ensuring the necessary O-enrichment of about 2 x 10( 17) O/cm(3) in the normal detector processing. Systematic investigations ha ve been carried out on various standard and oxygenated silicon diodes with neutron, proton and pion irradiation up to a fluence of 5 x 10(14)cm(-2) (1 MeV neutron equivalent). Major focus is on the changes of the effective do ping concentration (depletion voltage). Other aspects (reverse current, cha rge collection) are covered too and the appreciable benefits obtained with DOFZ silicon in radiation tolerance for charged hadrons are outlined. The r esults are reliably described by the "Hamburg model": its application to LH C experimental conditions is shown, demonstrating the superiority of the de fect engineered silicon. Microscopic aspects of damage effects are also dis cussed. including differences due to charged and neutral hadron irradiation . (C) 2001 Elsevier Science B.V. All rights reserved.