Techniques for the investigation of segmented sensors using the Two Photon Absorption -- Transient Current Technique

The Two Photon Absorption - Transient Current Technique (TPA-TCT) was used to investigate a silicon strip detector with illumination from the top. Measurement and analysis techniques for the TPA-TCT of segmented devices are presented and discussed using a passive strip CMOS detector as an example. The influence of laser beam clipping and reflection is shown and a method that allows to compensate these intensity related effects for the investigation of the electric field is introduced and successfully employed. Besides, the mirror technique is introduced, which exploits reflection at a metallised back side to enable the measurement directly below a top metallisation, while illuminating from the top.