No abstract available

No abstract available

[en] The dead time of photon counters which convert photon flux into an electric pulse sequence is extended and varies randomly. This study deals with the determination of the original intensity of an unsteady Poisson flux from the given recorded intensity and dead-time distribution function and of the dead-time distribution function from the input and recorded intensities. The results are sufficiently general to be applied not only to photon counters but also to other random-event detectors

[en] Characteristics of silicon avalanche-type photodiodes FD-115L(B) in the photon counting mode are studied. The avalanche-type photodiode was placed into a thermostat at liquid nitrogen temperature. The signal from the photodiode arrived at a preamplifier with the gain not less than 200. An amplitude pulse discriminator provided sensitivity ≤ 3 mB and loading up to 1.5x10^-8 s^-1. The experiments have shown that the bias voltage growth and cooling result in dynamic range expansion up to 10⁵. The photodiode dead time calculated by light characteristics is about 0.25 μs. The photon counter using the avalanche-type photodiode permitting to record light fluxes of 10^-16-10^-11 W in the 0.4-1.1 μm wavelength range

[en] The counting characteristics of single electron photomultipliers have been measured. The high-voltage boundary of the photomultiplier plateau is shown to be totally determined by the evolution of gas-discharge processes in the region between the last dynode and anode. The reduction in voltage between these electrodes leads to the plateau extension into the high-voltage region without the photomultiplier amplification

[en] Results of studying the temperature effect on the output pulse amplitude distribution, counting response and spectral sensitivity of the FEhU-62, FEhU-83 and FEhU-106 photomultipliers are given. Photomultiplier characteristics have been studied in the temperature range from +20 deg C to -40 deg C. It has been ascertained that in cooled photomultipliers their counting response plateau becomes more prolonged which allows the usage of an increased supply voltage. The sensitivity of cooled photomultipliers slightly increases in the blue part of spectrum and decreases in the red one. The measurements showed also that the dark noise of cooled photomultipliers rapidly decreases. Based on the gathered data an optimum temperature mode for various types of photomultipliers has been determined. For the FEhU-106 photomultiplier operating in the single-electron mode the optimal range of working temperatures constitutes from -15 to -20 deg C, while for the FEhU-62 and FEhU-83 - from -25 to -40 deg C

[en] Paper presents the results of investigation of silicon avalanche photodiodes at time gating under single-quantum detection. Dependences of densities of formation probabilities of dark and signal pulses on gating pulse duration are determined to be subject to the normal distribution. On the basis of the probability ratio one optimized duration and frequency of gating pulse sequence, value of stable voltage of reverse shift of avalanche photodiode

[en] An optimized version of photo-detectors selection criteria for photon counting is suggested. Use of the criterion for selecting a light boundary wave length during the transition from one photo-detector to another and for choosing dissectors (coordinate-sensitive detectors) is considered. The criterion suggested possesses a convenient simplicity for operative experimental application and turns out the most effective for cases when signal pulse counting rate exceeds shadow pulse counting rates. The criterion is easily generalized for the ares of high counting rates when due to the dead time effect the Poisson flow nature of recorded events is distorted

[en] The single-electron characteristics of several photomultipliers were investigated: FEU-71, -85, -86, -87. The possibility of selecting photomultipliers on the basis of manufacturer's ratings is examined. A formula for selection is given and the probability of success is indicated

[en] The change of counting rate of afterpulsings and luminosity intensity of near anode region of photomultipliers (PM) in the range of time up to 10³ after illumination of 10^-8-10^-6 W power has been studied. Connection of the phenomena and effect of illumination regime and photomultiplier power supply on these phenomena is shown. A conclusion is made that occasional powerful illuminations of PM can result in high increase of counting rate of dark pulses, noticeable even after hundreds of seconds after irradiation end. The value of illumination power is more important than the effect of its duration on PM. Luminosity appearing in near anode region of PM can cause photoelectron emission of photocathode and to a less degree is connected with the number of ions formed