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The experimental results of collecting lithium on the smooth and mesh collectors installed in the T-11M tokamak chamber with a vertical lithium limiter are presented. The collector (longitudinal) in the form of a long cylinder was installed in the near-wall region of the chamber along the toroidal axis of the tokamak. It was shown that a collector with a surface covered by several layers of stainless steel mesh collects lithium five times more than one with a smooth surface. The collection of lithium by a mesh collector with a different number of mesh layers was studied. It has been established that the most part of lithium collection (75%) is due to the two outer layers of the collector mesh. A simple mathematical model is proposed that describes the distribution of the collected lithium over the mesh layers. [ABSTRACT FROM AUTHOR]

At the HELIS ion accelerator, the dependence of the yield of DD nuclear-reaction products (neutrons and protons) on the angle of rotation of a Ti and CVD diamond (diamond obtained by chemical vapor deposition) target relative to the axis of the D+ ion beam at energies of E ≤ 35 keV is studied. Neutron detection is carried out by two independent methods: proportional counters filled with 3He and a scintillation detector with a stilbene crystal. Protons are detected using a diamond detector. The detectors are located on the side and behind the target. The CVD-diamond target has a polycrystalline structure and texture with the (100) grain orientation. The crystal structure of the titanium target is homogeneous and isotropic. The measurements show the dependence of the neutron flux recorded by the detectors located on the side and behind the target on the orientation of the target made of textured CVD diamond in the deuterium ion beam at energies of 25 and 30 keV. The proton yield from the CVD diamond target shows a dependence on the target-rotation angle at an energy of 25 keV. For the Ti target, no such effects are observed. The orientational dependence in the yield of neutrons and protons from textured diamond is explained by the effect of channeling deuterium ions in its structure. [ABSTRACT FROM AUTHOR]

The experimental data on the yield of d + d-reaction products for polycrystalline diamond target, obtained in the studies at the HELIS ion accelerator are presented. The equipment and neutron and charged particle detectors used in the study are described. The possibility of using the Unique Scientific Facility (USF) HELIS to verify operating characteristics of semiconductor detectors of alpha particles intended in studies of the boron–proton capture reaction at the Prometheus proton therapy complex is shown. [ABSTRACT FROM AUTHOR]

An Erratum to this paper has been published: https://doi.org/10.3103/S1068335623020094 [ABSTRACT FROM AUTHOR]

A spectrometer with digital signal processing is intended to make measurements at counting rates that are at least an order of magnitude higher than the limiting counting rate of an analog spectrometer. The tests have shown that the spectrometer operating in the maximum count rate mode compares well with the traditional analog spectrometer in such important characteristics as energy resolution, linearity, and noise immunity. The pilot version of the designed digital spectrometer was successfully used on the JET tokamak for recording energy distributions of fast charge exchange atoms with energies above 40 keV. [ABSTRACT FROM AUTHOR]

To study the evolution of the distribution function of fast ions with an ultimately high time resolution during both injection of neutrals and ion cyclotron plasma heating on the JET tokamak, we have developed a system for spectrometry of fast charge-exchange atoms, which consists of a spectrometric natural-diamond detector and a digital spectrometric channel. The main elements of the spectrometric system—the diamond detector, a noise-immune charge-sensitive preamplifier, and a fast analog-to-digital converter (ADC)—have been manufactured explicitly for use in spectrometry of fast charge-exchange atoms on the JET tokamak at high counting rates. The diamond detector that ensures the spectrometry of hydrogen atoms in the energy range 20–5000 keV is installed in the equatorial plane at an 18-m distance from the plasma axis at the end of the vacuum channel created for X-ray spectroscopy. A fast 14-bit ADC with 100-MHz sampling frequency and a 2-GB memory digitizes the preamplifier output signal. The developed digital spectrometric system can operate at a counting rate of up to ∼107 counts/s. Laboratory tests of the developed spectrometric system have shown that its energy resolution is no worse than the resolution of a similar analog system. In the experiments on the JET, the diamond digital spectrometric system ensures recording of the energy distributions of fast charge-exchange atoms with energies >40 keV. [ABSTRACT FROM AUTHOR]

A method for solving the inverse 2D Radon problem for a single temporal cross section as applied to the two-aspect-angle ITER neutron tomographic detection system is described. This method allows reduction of the calculation time owing to the formation of the reconstructed image described by models that are as simple as possible in the case of a single plasma filament (a spatial density distribution of the plateau, hill, crater, and banana type). These models are reduced to the approximation of the solution in the form of a superposition of two elliptic Gaussian curves (or the sum of an arbitrary number of circular Gaussian curves). [ABSTRACT FROM AUTHOR]

A measuring system has been developed to investigate the characteristics of radiation-induced optical absorption and radioluminescence in the spectral range of 400–1000 nm for a set of optical fibers being irradiated by fast neutrons and γ rays. This system has been used on the IR-8 research nuclear reactor to perform comparative tests of eight types of silica optical fibers from Heraeus (Germany), Fujikura (Japan), Mitsubishi (Japan), and the Fiber Optics Research Center of the Russian Academy of Sciences’ Prokhorov General Physics Institute. The measured dependences of the induced absorption and radioluminescence intensity versus the nuclear radiation wavelength, flux, and fluence, as well as the temperature, are analyzed. The microscopic mechanisms of induced absorption and radioluminescence are discussed. The values of induced optical absorption and radioluminescence in glass fibers containing H2 gas and having a hermetic coating (the technology for producing such fibers has been developed by the Fiber Optics Research Center) is found to be many times smaller than in other fibers. [ABSTRACT FROM AUTHOR]

The potential advantages of recording digital signals from ionizing-radiation detectors are considered. State-of-the-art high-speed analog-to-digital converters operating at sampling frequencies of 400 MHz (2.5 ns) and higher with a buffer storage of up to 4 Gbyte and a data-input rate of up to 400 Mbyte/s are capable of recording continuous pulse sequences with a throughput of >107 pulse/s in less than 10 s. In contrast to standard recording methods in which overlapping pulses are truncated, the recording of complete signal flows allows one to detect and resolve overlapping pulses quite well, provided they arrive within ≥20–40 ns of one another. [ABSTRACT FROM AUTHOR]

An X-ray tomographic system has been developed to measure the intensity of soft X rays and construct a two-dimensional profile of the electron temperature in plasma generated by the TOKAMAK T-11M facility. The system is based on cooled semiconductor CdTe detectors and is designed to operate in the energy range of 3–8 keV. [ABSTRACT FROM AUTHOR]