Speaker
Description
The Two Photon Absorption – Transient Current Technique (TPA-TCT) is a tool for the characterisation of particle detectors. Contrary to present state of the art TCT, TPA-TCT enables characterisation measurements with three dimensional spatial resolution. A tabletop setup for the investigation of silicon based detectors was commissioned at CERN to pioneer the technique. A 430 fs pulse fiber laser with a wavelength of 1550 nm is used, to generate excess charge by Two Photon Absorption in silicon. The laser light is focused so that excess charge is generated in a small volume (approximately 1µm × 1µm × 20µm) around the focal point. This talk presents the TPA-TCT setup at CERN SSD and shows recent investigation of radiation damage in 150 µm thick planar sensors fabricated by CIS. The beam depletion due to linear absorption and the influence on the refractive index are investigated. Furthermore, TCAD simulation are used to study TPA-TCT measurements in a PIN diode.
