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

34 2. Operation and Radiation Damage of Silicon Detectors2.4.2 Time Evolution of N effResults on the N eff time development show that all three types of defects are taking partin the time development of defects contributing to the space charge in the depleted region(g. 2.8). While the annealing part can be described with a sum of exponentials likethe leakage current and thus indicates decays of active defects, the nature of the reverseannealing part is not fully understood yet. The time development of the N eff can thusbe parametrised asN eff (t) =N C + X iN i e ;t= i+ N Y (t) (2.65)where N C represents defects constant in time, N i defects that anneal with time constants i and N Y defects responsible for the reverse annealing. 16 Depending on the reactionsresponsible for reverse annealing, N Y (t) is described by equations 2.57, 2.59 or 2.61,depending on the type of reaction(s) responsible for the reverse annealing. Agreement ofthe measured results with dierent options will be presented later in this work.*16Defects contributing to the charge in the SCR are not necessarily the same as those contributing tothe leakage current, thus also time constants may dier.