SiPM angular response and enhanced light extraction

Optical coupling of scintillators with photodetectors is important to increase the achievable light output. Understanding the angular response of photodetectors is crucial to enhance the light extraction. Losses induced by Fresnel reflections on a Silicon Photomultiplier (SiPM) surface result in an angular dependence of the detected signal on incident light. We built a dedicated test bench at CERN to make a systematic study on samples of various specifications and manufacturers. We present the results of this study.