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Single photon counting system for biomedical applications was designed and tested. Examination ofchanges ofan optical signal on a patient's head during stimulation tests (finger taping) was made by the elaborated system.

A sim ple sta tis ti cal the ory of ra di a tion dam age of semi con duc tor mem ory has been constructed. The ra di a tion dam age of EPROM mem ory has been in ves ti gated. The mea sured num ber of dam aged bytes is sig nif i cantly lower than the ex pected num ber re sult ing from the purely ran dom dis tri bu tion of the dam aged bits. In this way it has been proven that there is a cor re la tion be tween the fail ures of in di vid ual mem ory bits which are lo cated in the same byte.

A fully automated measurement system has been built to measure uniformmity of the parameters of SiPM detectors with very high pixel densities. It has a light source with a microfocus spot (FWHM = 3 µm at the detector surface) and a precise positioning system (1 µm accuracy). A temperature control system with water cooling has been used to set the temperature of the measured detector. Finally, a low noise, custom made front-end amplifier has been designed to receive SiPM signals. This paper presents the MAPD-3N detector measurement results-uniformity of gain and relative photon detection efficiency (PDE).

The article presents the analysis of the dead time measurement using two sources for a non-paralyzable detector. It determined the optimum division of count rate measurement time between both source measurement and a single source one. Results of the work can be used to optimize dead time measurement for systems which count photons or particles.