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 results of measurements of the DD-reaction yields from the Pd/PdO:Dx and the Ti/TiO2:Dx heterostructures in the energy range of 10-25 keV are presented. The neutron and proton fluxes are measured ...using a neutron detector based on 3He-counters and a CR-39 plastic track detector. Comparisons with calculations show the significant effect of DD-reaction yield amplification. It was first shown that the impact of H+(protons) and Ne+ ion beams in the energy range of 10-25 keV at currents of 0.01-0.1 mA on the deuterated heterostructure results in appreciable DD-reaction yield enhancement.
At the ion accelerator HELIS at LPI, the neutron yield is investigated in DD reactions within a strongly textured polycrystalline deuterium-saturated CVD diamond under irradiation by a deuterium ion ...beam with the energy of less than 30keV. The measurements of the neutron flux in the beam direction are performed using a multichannel detector based on 3He counters, in dependence on the target angle, β, with respect to the beam axis. A significant anisotropy in the neutron yield is observed. At β=0° the yield is higher by a factor of 3 as compared to that at β=±45°. The possible reasons for the anisotropy, including ion channeling, are discussed.
The passage of fast neutrons through the crystal structure of a textured diamond obtained by chemical vapor deposition (CVD diamond) is studied. Neutrons with an energy of 2.45 MeV from the DD ...reaction and with an average energy of about 2 MeV from the
252
Cf isotope are used as neutron sources. The neutrons are detected by two independent methods: using proportional counters filled with
3
Не and a paraterphenyl-based scintillation detector. The measurements show that the neutron-flux incident on the detector depends on the orientation of the target. In the case of isotropic samples containing diamond and carbon, such effects are not observed. A possible explanation for the effect is the channeling of deuterium ions and neutrons in channels of textured CVD diamond.
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.
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.
The yields of nuclear reactions in textured CVD (chemical vapor deposition) diamond samples irradiated with a deuteron ion beam are measured. The sample orientation in the deuteron beam is shown to ...influence the value of the DD reaction yield. The X-ray fluorescence spectra from the surface of deuterated targets irradiated with an ion beam are studied. Analysis of the fluorescence spectra revealed “additional” peaks which cannot be associated with any known elements and require separate studies.
Two independent methods based on a neutron detector with He-3 counters and a CR-39 track detector are used to measure neutron and proton emissions from the nuclear reaction in samples of deuterated ...structures of textured CVD (chemical vapor deposited) diamond, palladium, and zirconium irradiated with X-ray quantum beams. It is demonstrated that, in solid-state deuterated targets, the DD reaction can be stimulated by X-ray quanta with energies of 20−30 keV.
The test setup for silicon pixel modules at Lebedev Physical Institute of the Russian Academy of Sciences is presented. The test algorithm and experience are described. The possibility of using this ...setup for testing SPD detector modules is discussed.
The results of 5 years of development of the inner tracking system of the HERA-B experiment and first experience from the data taking period of the year 2000 are reported. The system contains 184 ...chambers, covering a sensitive area of about
(20×20)
cm
2
each. The detector is based on microstrip gas counters (MSGCs) with diamond-like coated (DLC) glass wafers and gas electron multipliers (GEMs). The main problems in the development phase were gas discharges in intense hadron beams and aging in a high radiation dose environment. The observation of gas discharges which damage the electrode structure of the MSGC led to the addition of the GEM as a first amplification step. Spurious sparking at the GEM cannot be avoided completely. It does not affect the GEM itself but can produce secondary damage of the MSGC if the electric field between the GEM and the MSGC is above a threshold depending on the operation conditions. We observed that aging does not only depend on the dose but also on the spot size of the irradiated area. Ar–DME mixtures had to be abandoned whereas a mixture of 70% Ar and 30% CO
2 showed no serious aging effects up to about
40
mC
/cm deposited charge on the anodes. X-ray measurements indicate that the DLC of the MSGC is deteriorated by the gas amplification process. As a consequence, long-term gain variations are expected. The Inner Tracker has successfully participated in the data taking at HERA-B during summer 2000.
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