Speaker
Description
To study the charge collection efficiency of radiation-damaged silicon
sensors, frequently red and near-infrared light is used to generate
electron-hole pairs . In order to determine the absolute number of
produced charge carriers, the light absorption coefficient, $\alpha$,
has to be known.
To study the change of $\alpha$ due to radiation-induced defects, we
have measured the transmission of light with wavelengths between
1-2\,$\mu$m through silicon samples irradiated to
1$~$MeV-neutron-equivalent fluences between 0 and $1 \times
10^{17}~$cm$^{-2}$.
In this contribution, the results of these measurements will be
presented: the contribution of the irradiation to $\alpha$ was found to
scale with fluence for the entire fluence range investigated. In the
wavelength region around 1.8\,$\mu$m, evidence for the production of the
radiation-induced divacancy defect $V_{2i}^0$ with a density
approximately proportional to the fluence was found. For the band-gap
energy, no fluence dependence was found within the experimental
uncertainties.
