Analysis methods for highly radiation-damaged SiPMs

Prototype SiPMs with 4384 pixels of dimensions 15×15μm2 produced by KETEK have been irradiated with reactor neutrons to eight fluences between 109 and 5×1014 cm−2. For temperatures between −30∘C and +30∘C capacitance–voltage, admittance–frequency, current–forward voltage, current–reverse voltage and charge–voltage measurements with and without illumination by a sub-nanosecond laser have been performed. The data have been analysed using different methods in order to extract the dependence on neutron fluence and temperature of the electrical parameters, the breakdown voltage, the activation energy for the current generation, the dark-count rate and the response to light pulses. The results from the different analysis methods are compared.