Münster 2017 – scientific programme
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T: Fachverband Teilchenphysik
T 69: Halbleiterdetektoren (Strahlenschäden, neue Konzepte)
T 69.3: Talk
Tuesday, March 28, 2017, 17:15–17:30, VSH 11
Absorption of near infrared light in highly irradiated silicon — •Christian Scharf, Robert Klanner, Erika Garutti, and Finn Feindt — Institute for Experimental Physics, Hamburg University, Luruper Chaussee 149, D-22761 Hamburg, Germany
An increase of the absorption coefficient of near infrared light in silicon was investigated after irradiation with protons with momenta of 23 GeV to fluences of up to 1.3·1016 neq/cm2. Near infrared light is frequently used to study the radiation damage of silicon sensors. To interpret the measurements, the charge deposited by the laser light, which depends on the absorption coefficient, has to be known. The absorption coefficient of silicon was determined at room temperature as a function of the fluence and at wavelengths between 1000 and 1300 nm using a spectrophotometer. Additionally, the absorption coefficient of silicon was determined at a wavelength of 1052 nm as a function of the fluence and applied voltage at -20 ∘C and -30 ∘C using the University of Hamburg edge-TCT setup. An increase of the absorption coefficient of silicon with fluence and a decrease with the applied voltage were observed. The results are compared to charge collection measurements on irradiated pad diodes using pulsed laser light of 1064 nm wavelength.