The management and control system of the cold neutron moderator allows the engineering staff to monitor, in the process of its operation, the main parameters of the moderator, including the gas blower rotation speed, the consumption and temperature of helium, the vacuum in the jacket and the passage of pellets in the transport pipe. Today, complex upgrading of the cold neutron moderator at the fast pulsed reactor "IBR-2M" is underway. The paper presents the current version of the structure of the management and control system for the cold moderator. Interface convertors are used to connect the management and control equipment of the cold moderator to the computer. The main interface of the data acquisition and control system of the executive devices is RS-485. Specialized software has been created to operate the management and control system of the cold neutron moderator.

The temporal characteristics of a time-of-flight spectrometer installed on the first channel of the IBR-2 reactor are investigated. A change in the flash time of the reactor relative to the start depending on the measurement time from the beginning of the reactor operation cycle is discovered. The neutron deceleration time is measured as a function of the neutron wavelength. A dependence of the half-width of the reflections on the neutron wavelength is established. The measurements are carried out in a wide range of Bragg angles from 0.0567232 to 0.34180977 rad (from ~3° to ~19°). An estimate is made for the mosaic pattern of a single crystal.

Using a multidetector system on the YuMO spectrometer allows shortening the time of measurements. The quantitative comparison of the measurement time using one and two-detector mode is done. The time range for experiments was from several minutes up to 12 hours. It was shown that two-detector system shortens more than twice the time of the measurement. While making a structural investigation using advanced software the two-detector system allows to treat the data at a qualitatively new level. An example illustrating the features of the channels choice and measurement time on the spectrometer was shown. The results of this paper could be used when planning the experiments on the YuMO spectrometer, for modernization of the installation and for equipment using time-of-flight method.

This paper presents the results of experiments performed at the cold moderator test stand with beams 1, 4–6, and 9 for studying the possibility of loading the moderator chamber with frozen balls (pellets) 3.5 to 3.8 mm in diameter through the cryogenic pipeline of complex configuration with a 4-m-long section ascending at an angle of 50°. The optimum parameters for the successful loading of the moderator chamber are found to be the following: mass flow rate of the carrier gas (helium), 2 g/s; temperature of the pipeline walls and helium, 79–85 K; angular velocity of the disc in the ball dispenser, 3.6°/0.5 s; ball ejection rate from the dispenser to the pipeline, 8 balls/s; and maximum chamber loading time, 6 h. During the construction of the test stand, the cryostat is replaced with a new one with two gas blowers, which is necessary for maintaining a low temperature in two independent cooling circuits (for two cold moderators or for a cold moderator and the test stand) and the software for the control of the operation parameters is modified.

In July 10, 2012 cold neutrons were generated for the first time with the unique pelletized cold neutron moderator CM-202 at the IBR-2M reactor. This new moderator system uses small spherical beads of a solid mixture of aromatic hydrocarbons (benzene derivatives) as the moderating material. Aromatic hydrocarbons are known as the most radiation-resistant hydrogenous substances and have properties to moderate slow neutrons effectively. Since the new moderator was put into routine operation in September 2013, the IBR-2 research reactor of the Frank Laboratory of Neutron Physics has consolidated its position among the world’s leading pulsed neutron sources for investigation of matter with neutron scattering methods.

In the paper “Nuclear neutron precession” [1], which marked the beginning of a new research area – neutron optics of polarized media, it has been theoretically shown that the dependence of the refractive index of a neutron wave on mutual orientation of spins of the neutron and nucleus determines the neutron spin rotation around the direction of the target polarization. The precession frequency  depends on nuclear spin I, density of nuclei N and difference f + – f – of amplitudes of neutron scattering by this nucleus corresponding to the states with total momentum of the

The design and main characteristics of a test setup for studying the serviceability of the bead cryogenic neutron moderator and determining its optimal operating conditions on the fast pulsed IBR-2 reactor are presented. Using the test setup, the possibility has been demonstrated of filling the moderator chamber with the working medium—beads of a mixture of aromatic hydrocarbons, delivered to the chamber by a cold (T < 85 K) helium gas flow over an intricately shaped cryogenic pipeline system.

Описана модернизация детекторной системы и системы управления нейтронным порошковым дифрактометром (н.п.д.) на канале ГЭК-5 реактора ВВР-ц (филиал ФГУП “НИФХИ им. Л.Я. Карпова”, Обнинск). Cоздан подключенный к персональному компьютеру аппаратно-программный комплекс, обеспечивающий сбор и накопление данных, а также управление экспериментом. Кратко описаны разработанные в ЛНФ ОИЯИ основные блоки системы автоматизации н.п.д. и управляющего программного комплекса Sonix+. Модернизация позволила увеличить светосилу дифрактометра и полностью автоматизировать процесс измерений.

The modernization of the detector system and control system of the neutron powder diffractometer (NPD) in the GEK-5 channel of the VVR-c reactor (Obninsk Branch, Karpov Institute of Physical Chemistry) is described. The PC-connected hardware and software complex, which ensures data acquisition and storage and control of the experiments, is created. The main modules of the NPD automation system and Sonix+ control software package, designed at the Frank Laboratory of Neutron Physics at JINR, are briefly described. The modernization has made it possible to increase the luminosity of the diffractometer and completely automatize the measurement process.

Equipment and software for recording time-of-flight spectra with a small channel width (10 ns) in precision experiments under conditions of low neutron beam intensities or recording rare events have been designed. An eight-input time encoder operates without losses when the signal intensity is up to 10 5 s −1 at any of the eight inputs. The use of the USB interface ensures the system mobility. The developed system integration procedure from components in the executed format allows one to obtain a distributed system, ensures a higher succession of the software, and the possibility of assembling the system by the user.

Main features of the modernized small-angle neutron scattering spectrometer (YuMO) at IBR-2M pulsed reactor are described. New installations for sample environment of the spectrometer are highlighted. The modernized SANS instrument (YuMO) is equipped with a new type of position sensitive detector as well as two detector system which provide a unique dynamic range (Qmax/Qmin ratio is about 90). Sample environment is extended with a magnetic system (magnetic field about 2.5 Tesla), automated high pressure setup which allows simultaneous SANS and volumetric high pressure studies and light illumination system. In particular, these developments led to considerable improvements of resolution of the instrument (about 1%) and opened the possibility to study anisotropic materials and perform efficient high pressure studies.

In connection with commissioning of the IREN pulsed resonance neutron source new electronics and appropriate software are developed for registration of time-of-flight spectra with small width of the channel (21 ns). The hardware-software system is intended for research of the IREN neutron beam characteristics, properties of new detectors, and also for performance of precision experiments under conditions of low intensity or registration of rare events.

A mechanical monochromator of slow neutrons that is intended for the use in a small-angle neutron scattering spectrometer constructed on a neutron beam of the SAFARI-I reactor (NECSA, South Africa) is described.

A spectrometric setup for studying the resonance structure of the total and partial neutron cross sections at energies below 10 keV has been created. The setup consists of two rotor-type mechanical neutron choppers with dc motors, an electronic system for stabilizing the rotation of rotors and phasing the moment of opening slits along a neutron beam with a neutron pulse, collimators, and neutron detectors. The angular rotational velocity of rotors changes from 0 to 6000 rpm, and their synchronization with the neutron pulse is provided with an accuracy of 10 μs at a minimum time of opening slits along the neutron beam of 20 μs. The setup is transported easily and can be placed on any neutron beam of the ИБР-2 fast pulsed reactor or other neutron sources. The values of the measured basic characteristics of the spectrometer agree with the calculated values within the experimental errors.