Characterization Measurements Methodology and Instrumental Set-Up Optimization for New SiPM Detectors - Part II: Optical Tests

A comprehensive and in-depth characterization procedure for obtaining very accurate measurements on silicon photomultiplier detectors (SiPMs) is here described. A large amount of optical tests are systematically carried out and discussed in terms of the most important SiPM performance parameters; in particular, an accurate estimation of the photon detection efficiency in the 350-900-nm wavelength spectral range and in steps of 10 nm is achieved, based on the single-photon counting technique, with substraction of the dark noise contribution and avoiding the additional noise sources of crosstalk and afterpulsing. Some recently produced detectors are analyzed and their relevant electro-optical parameters are evaluated in order to demonstrate the effectiveness and efficacy of the adopted characterization procedure and data-handling protocols in assessing the overall SiPM performance, regardless of the specific device tested. Tests repeatibility is carefully verified and all the evaluated parameter trends are proved to be compatible with the physics theory of the SiPM device.