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A module for recording single-photon pulses is described. It is able to reliably operate in the mode of single-photon counting at a wavelength of 1550 nm (the minimum attenuation in quartz fibers). For this purpose, unique avalanche photodetectors (APDs) based on InGaAs/InP heterostructures with the three-stage cooling to temperatures of -50°C via Peltier elements are used during reception. Test measurements of the level of noise counts, including both dark pulses and afterpulses, have been performed using the developed testing system. The dependences of the recorded noise counts on the duration of gate pulses have been obtained. The nonlinear character of these dependences is evidence of the difference in the contributions of the afterpulsing effect and the dark pulses of the APDs to the noise counts. At short durations of the gate pulses, the major contribution to the noise counts is made by dark pulses of the APDs. [ABSTRACT FROM AUTHOR]

An X-ray detector with a dielectric (KU1 optical glass) used as a sensitive element is described. Operation of the detector is based on the discovered effect of electric-field generation in a dielectric under exposure to radiation. The measurements were taken at the Angara-5-1 facility, at which the radiation source is megaampere Z-pinch plasma. It is shown that when the radiation power incident on the detector is approximately 1 MW/cm2, the detector response is a few volts with a time resolution of 1-2 ns. This effect is thought to be caused by “hot” electrons induced by radiation in the dielectric. The estimates for these experimental conditions are presented. [ABSTRACT FROM AUTHOR]