Study of radiation damage in silicon detectors for high ... - F9

8ConclusionsA systematic study of radiation damage in silicon bulk was performed under controlledconditions. Two irradiation sites at the TRIGA reactor near Ljubljana were equippedto provide mounting, cooling, biasing and measurements of samples during neutron irradiations.They were used to irradiate a number of high resistivity ( = 3 ; 30 kcm)p + -n-n + diodes used in this work. Irradiation ux, sample temperature and bias voltagewere carefully controlled during irradiations to obtain good control over irradiationconditions.The resented results were obtained from more than two years of measurementsof bulk properties of irradiated samples. Full depletion voltage and reverse current weremeasured in regular intervals both during and after irradiation. To follow defect annealingand reverse annealing under well dened conditions, storage temperature and bias voltagewere controlled during irradiation and storage.In the scope of this work, the rst systematic study of the dependence of the radiationinduced bulk damage in silicon on the neutron ux has been performed. Fastannealing of N eff and reverse current were studied at temperatures from 0 to 15 C. Afterwards,most samples were heated to 60 C to accelerate time development. Long termannealing of reverse current and reverse annealing of N eff were studied and kinematicsof the responsible processes was searched for. Finally, the eect of the bias voltage ondefect development was discovered [55] and rst results of its study are presented.Fast annealing of N eff and reverse current A signicant annealing of both N effand reverse current on a day scale even at 0 C was observed [56]. Though it bears nogreat importance for LHC experiments, it should be taken into account when results fromdierent groups are compared.109