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Introduction. At present the most accurate estimate of ranges is specific to laser range finders using phase measuring techniques. Design of a pulsed laser range finder with short probe pulses enabling one to gain high resolution and accuracy of estimate of target range close to the phase range finders is the topical problem.Aim. Development of a receiving part of the pulsed laser rangefinder with precision characteristics; determination of the accuracy of the measurements; description of the hardware.Materials and methods. The construction of the receiving part of the precision pulsed laser rangefinder with a two-scale digital range estimation system implemented by counting clock generator pulses and an analog integrator that specifies the discrete range estimation was considered. Using the methods of mathematical statistics, the energy characteristics of the rangefinder were determined: the accuracy of the range estimation and the probability of false alarm were provided by the developed scheme. The hardware of the precision laser rangefinder was described.Results. The principles of implementation of the receiving part of the laser rangefinder with a two-scale digital system for estimating the distance to the object were given. The results of numerical simulation of rangefinder characteristics were obtained, confirming the accuracy of range estimation of the order of millimeters. In the implemented rangefinder scheme, the probability of false alarm was 10-4 during 200 s of observing signal and noise mixture. The hardware of the precision laser rangefinder with a digital two-scale range estimation was proposed.Conclusion. The implemented laser range finder approaches to the capabilities of phase laser rangefinders in terms of potential accuracy of distance up to millimeters, while implementing the specified parameter in rapidly changing phono-target environment. Using of short probing pulses with a duration of 10...20 ns allows one to achieve a resolution of up to 1.5 m. In contrast to the phase rangefinder the range can be estimated from a single probe pulse.

If the neutron fields at personnel workplaces differ from the neutron fields in which individual dosimeters are verified, there is a possibility of additional errors in the assessment of such dosimetric quantities as ambient dose equivalent, individual dose equivalent or effective dose. To take into account the energy distribution of the neutron radiation flux density and the geometry of the irradiation of workers, it is necessary to study the characteristics of the fields of neutron radiation at the workplaces of the personnel. In order to obtain conditionally true levels of personnel exposure to neutron radiation at nuclear facilities, studies of the energy and angular distribution of the neutron radiation flux density were carried out at the workplaces of the Institute of Reactor Materials JSC, Zarechny. The energy distribution of the neutron radiation flux density was obtained using an MKS-AT1117M multi-sphere dosimeter-radiometer with a BDKN-06 detection unit and a set of polyethylene spheres-moderators. The angular distribution of the neutron radiation flux density was estimated from the results of measurements of the accumulated dose of neutron radiation by individual thermolumines-cent dosimeters placed on four vertical planes of a heterogeneous human phantom. The results of measurements of the energy and angular distribution of the neutron radiation flux density made it possible to estimate the conditionally true values of the ambient and individual dose equivalents. The calculated conventionally true values differ from the measured values from 0.7 to 8.9 times for the ambient dose equivalent and from 6 to 50 times for the individual dose equivalent. In order to reduce the error in assessing the effective dose of personnel using personal dosimeters, correction factors were determined. For different workplaces and types of personal dosimeters, correction factors are in the range of values from 0.02 to 0.16. © 2021, Saint-Petersburg Research Institute of Radiation Hygiene after Professor P.V. Ramzaev. All rights reserved. Работа выполнена при поддержке гранта Президента Российской Федерации (грант № МК-4027.2021.4) и при финансовой поддержке РФФИ в рамках научного проекта № 19-38-90096.

This paper proposes a method for measuring the position of radiation centers for an ultra-wideband combined antenna (CA) in the pulsed mode. The radiation centers for E- and H-planes of the antenna are determined. Antenna rotation in these planes, with respect to an arbitrary axis, results in the time delays (advances) of the recorded receiving pulses for various angles. The purpose of the measurements is to find the rotation axes providing minimum time delays of the radiated pulse registration at the receiving antenna for the largest possible range of observation angles. These rotation axes pass through local areas (radiation centers) in the antenna volume. Simple analytic formulas refining the position of the radiation center from an arbitrary measurement are proposed. In the simulations, a code based on the FDTD method was used. The CA has at least two radiation centers. Radiation center of the H-plane is located at 1/3–1/2 of the antenna length counting from its rear wall, slightly below the antenna’s half height. Radiation center of the E-plane is located near the aperture plane of the antenna, also slightly below the antenna’s half height.