The energy spectrum of alpha particles from the nuclear reaction p +11B- 3 alpha was studied using the beam of the injector of the proton synchrotron of the Prometheus proton therapy complex. The reaction products (alpha particles) were recorded using a CR-39 track detector. The detectors were calibrated using a241Am radioactive source. It was determined that mainly alpha particles emitted from the boron target have energies from 3 to 5.5 MeV. In this case, a significant part of the alpha particles emitted from the depths of the target have significantly lower energies compared to the calculated ones due to ionization losses. Measuring the energy spectrum of alpha particles from targets containing boron is of great scientific and practical interest for identifying the mechanisms of boron-proton capture therapy and determining the additional contribution to the therapeutic effect of proton irradiation.

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.

The yield of the nuclear reaction B + p → 3α near the resonant proton energy of 675 keV in the injector beam of the “Prometheus” proton accelerator is studied. The reaction products (alpha particles) are recorded using a CR-39 track detector. The alpha particle yield from the boron target is estimated as ~10 –4 per proton.

The results obtained by experimentally and theoretically studying the yield of the promising nuclear-fusion reaction $${}^{11}$$ B( $$p,3\alpha$$ ) initiated by powerful picosecond laser radiation of intensity $$3\times 10^{18}$$ W/cm $${}^{2}$$ are presented. A new procedure that relies on a simultaneous detection of the yield of alpha particles and the neutron yield in the reference reaction $${}^{11}$$ B $$(p,n)^{11}$$ C and which permits reaching a high precision of measurements is employed. The measured alpha-particle yield per pulse in the reaction $${}^{11}$$ B( $$p,3\alpha$$ ) is 10 $${}^{9}$$ particles in 4 $$\pi$$ sr at the above laser-pulse parameters. The results of a numerical particle-in-cell (PIC) simulation of the nuclear-fusion reaction $${}^{11}$$ B( $$p,3\alpha$$ ) proceeding in a solid-state boron target are presented. These results on the alpha-particle yield per pulse in the reaction $${}^{11}$$ B( $$p,3\alpha$$ ) agree fairly well with experimental results.

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.

The possibility of neutron generation by irradiating deuterated crystalline structures with an electron beam with an energy of 20–40 keV was studied. As targets, the deuterated crystalline structures of palladium and textured CVD diamond were used. Measurements of neutron emission are presented, which were carried out by three independent methods—scintillation detectors, counters based on He-3, and track detectors CR-39.The average neutron flux during irradiation was estimated as 1–10 s $${}^{-1}$$ in 4 $$\pi$$ sr.

The paper reviews results obtained in the course of low energy nuclear reactions experimental study using the HELIS facility (LPI). The analysis of DD-reaction yields in deuterated crystalline structures at deuteron energies of 10–25 keV has shown a significant amplification effect. It was found that the exposure of deuterated targets both to 10–25 keV H+ and Ne+ ion beams and 20–30 keV X-ray radiation beams results in stimulation of DD-reaction yield. For CVD diamond and PdDx targets, it was shown that the magnitude of the neutron yield is affected by the orientation of the sample with respect to the deuteron beam. The possible explanation of the said effect may be attributed to the channeling of deuterium ions and neutron (DD reaction products) in textured targets. It was found that the heat release is much higher when D+ ion beams act upon the TiDx target than in case with H+ and Ne+ beams. The heat release depends upon the deuterium concentration in the target and the deuteron beam current density. “Additional peaks” were observed in the X-ray fluorescence spectra, but those are not related to any element and are seemingly associated with diffraction processes in deuterated palladium and CVD diamond.

A neutron detection system at the HELIS setup created by the Lebedev Physical Institute is based on proportional counters. Systems for shaping, discriminating, reading, digitizing, and processing signals from 36 SNM18 proportional neutron counters are. The location of the counters in all directions around the analyzed target made it possible to perform a set of experiments to study the angular dependences of neutron yields in the DD reaction in deuterated crystal structures at deuteron energies of 10–25 keV, as well as to stimulate the DD reaction with ion beams.

The interaction between a deuterium ion (D+) beam and deuterium-enriched Pd and Ti targets are studied using the HELIS ion accelerator (Lebedev Physical Institute). The neutron yield is determined from the DD reaction in the deuterated Pd target whose surface is irradiated with a D+-ion beam with an energy of 20 keV. The neutron flux is measured in the D+-ion-beam direction as a function of the angle β of target rotation relative to the beam axis using a multichannel detector based on 3He counters. Significant anisotropy (orientation effect) of the neutron yield is observed; it is two times higher at β = 0° than at β = ±30°. The orientation effect can be associated with channeling and the so-called flux-peaking effect. It is studied by computer simulations using the BCM-2.0 code. The enhanced density of the D+ flux between the (200) planes of a Pd crystal (where implanted D is located) at zero angle of incidence with respect to these planes makes it possible to qualitatively explain the observed orientation effect. No effect is observed in a homogeneous target of deuterated titanium.

The emission of X-ray quanta, neutrons, and charged particles from deuterated structures under X-ray irradiation is studied. Targets (deuterated chemical-vapor-deposited (CVD)-diamond, palladium, zirconium, and titanium) are irradiated with the use of an X-ray tube equipped with a polycapillary lens with an energy of up to 30 keV and an X-ray tube equipped with a collimator with an energy of up to 25 keV. Different types of detectors, such as a multichannel neutron detector based on He-3 counters, a CR-39 plastic track detector, and silicon surface barrier detectors, are used. The emission of neutrons with an energy of above 10 MeV and alpha particles with an energy range of 7–15 MeV is revealed. This result indicates the possibility of stimulating multiparticle fusion reactions between deuterium nuclei in solid deuterated structures. The analysis of X-ray fluorescence spectra demonstrate the existence of “additional” peaks, which cannot be identified by any characteristic X-ray fluorescence line. Their appearance cannot be associated with any known element or diffraction process. The nature of the origination of the “additional” peaks requires special study.

At the ion accelerator HELIS at the LPI, the neutron yield is investigated in DD reactions in deuterated Pd target, during an irradiation of its surface by a deuterium ion beamwith the energy 20 keV.Themeasurements of the neutron flux in the beam direction are performed in dependence on the target angle, β, with respect to the beam axis. These measurements are performed using a multichannel detector based on He3 counters. A significant anisotropy in neutron yield is observed, it was higher by a factor of 2 at β=0 compared to that at β = ±30o. The possible reasons for the anisotropy, including ion channeling, are discussed. A similar effect was observed earlier when irradiated deuterated CVD diamond samples with a deuterium ion beam [1]. To explain the experimental results, we used the computer code earlier applied in [2] to interpret the orientation effect in the neutron yield from deuterated C(400) target irradiated by 20 keV deuteron beam. The code allows calculation of the deuterons flux under channeling condition. Now, the code is modified in order more exactly take into account the dependence of reaction probability on impact parameter. The dependence on impact parameter was “constructed” conjugating the classical definition of reaction cross-section (integral over impact parameters) from one side, and real yield of DD reaction from another side, which is the convolution of energy-dependent cross-section (includes astrophysical S-factor), effect of screening, and energy loss.

Measurements of emission from nuclear reaction products (neutrons and protons) have been carried out appearing in the deuterated structures of textured CVD diamond, palladium, titanium, and zirconium under irradiation with a beam of X rays using independent methods (neutron detector based on He-3 counters, Si surface-barrier semiconductor detectors and CR-39 track detector). The possibility of enhancement of both DD reaction and multi-particle deuterium fusion by the beam of X rays with energy ranging 20–30 keV in solid deuterated targets has been established. Analysis of X-ray fluorescence spectra of the target bombarded by beams of ions has revealed “additional” peaks, the occurrence of which cannot be related to any of the known elements, and requires separate study.

The results of studies of the interaction of ion beams and X-ray quanta with deuterated crystal structures at the HELIS facility (LPI) are presented. Results on research of DD-reactions in deuterated crystal structures at deuteron energies 10 - 25 keV show significant enhancement effect. It is shown that the effect of the beams of ions Ne+ and H+ at energies in the range of 10 - 25 keV and a beam of X-radiation of 20 - 30 keV for deuterated target leads to stimulation of DD-reaction. For the target of CVD-diamond it is showed that the orientation of the sample with respect to the deuteron beam affects the neutron yield. Targets (deuterated CVD diamond, palladium, zirconium and titanium) were irradiated with both ion beams and X-ray quanta using an X-ray tube with an energy of up to 30 keV. Analysis of X-ray fluorescence spectra from deuterated targets of CVD diamond and palladium revealed "additional" peaks that are not identified by any of the characteristic radiation lines. Their appearance cannot be connected with any known element, as well as with diffraction processes.