S. I. Kuznetsov

Neutron emission during a nanosecond discharge in deuterium in a nonuniform electric field

Neutron emission during a nanosecond deuterium discharge formed at the nonuniform electric field is investigated. A stable neutron yield is observed when the cathode is made of metallic plates covered by a layer of deuterated zirconium and the anode is made of stainless steel in the form of a tube. It is shown that, when the deuterium pressure equals several Torr, neutrons are emitted from both deuterated and deuterium-free cathodes. The influence of the anode design on the neutron yield is studied.

X-ray production by 500 MeV electron beam in a periodically structured monocrystalline target of GaAs

Abstract The experiment at the Tomsk synchrotron on generation of 27 keV X-rays by 500 MeV electrons in a new type of a periodical crystalline target is presented. The target has been made on the surface of a GaAs crystal plate by means of microlithography. The etched microstructure is a system of about 300 strips, 14 μm thick, 100 μm high and the gaps between the strips are 29 μm. The measured spectra and orientational dependences of the X-rays emitted at a Bragg angle are discussed. The generated radiation consists of parametric X-ray radiation (PXR) and diffracted X-ray transition radiation (DTR). It is shown that the intensity of the DTR component of generated X-rays is much higher than that of the PXR.

Setup for study of radiation in VUV region generated by 5.7 MeV electrons in a multilayer mirror

The experimental setup created for investigating the radiation in the vacuum ultraviolet (VUV) region generated by 5.7 MeV electrons in a multilayer X-ray mirror at different angles of the electron beam incidence on the X-ray mirror surface is described. The method proposed for parametric X-rays separation from the generated radiation is analyzed. The method is based on the K-edge effect of photon absorption in fluorine at transmission of generated radiation through a thin Teflon filter. The results of the first test measurements are discussed.

On the orientation effect of the neutron yield increase in d(d, n)3Hе reactions at an energy of 7–12 keV in TiD2 crystals

The orientation dependence of the d(d, n)3He reaction probability in a TiD2 crystal at a deuteron energy of 7–12 keV is investigated. The BCM-1.0 code developed for calculating the trajectories of channeled particles within classical mechanics is used to simulate deuteron trajectories at (200)-planar channeling in a 0.15-μm-thick Ti crystal with the angular divergence of the beam taken into account. The enhancement of the reaction probability in the computer experiments is 2.1 in the case of a parallel deuteron beam and near-zero crystal entry angles relative to the (200) planes. In the case of a deuteron beam with its angular divergence equal to 1/5 of the critical channeling angle, the maximum reaction-probability enhancement is 1.5. The results of calculations agree qualitatively with recent experiments performed at Tomsk Polytechnic University.

Influence of field ionization on the efficiency of neutron generation

The results of experiments on neutron generation caused by nanosecond discharges in a deuterium medium are presented. The experiments are performed using two types of potential electrodes (anodes). One of them is fabricated from steel foil, and the other is composed of tungsten wires with split ends. In both cases, a deuterium-saturated zirconium plate is employed as a flat grounded cathode. With a tungsten anode, deuterium ions generated by field ionization are demonstrated to constitute the determining part of ions involved in the acceleration process and the neutron yield arising from the reaction 2H(d, n)3He is about four times greater than that inherent to the steel-foil anode. In this case, the maximum neutron yield is 1.2 × 104 neutron/ shot, and the duration of neutron emission from the cathode is 1.5 ns.

Local structure of titanium nitride-based coatings

The fine structure of X-ray absorption spectra near the K edge and the extended fine structure of X-ray absorption for titanium, copper, and chromium in nanocrystalline coatings based on titanium nitride doped with copper, chromium, and silicon are experimentally studied. The samples are prepared by the evaporation of composite cathodes using the vacuum arc plasma-assisted method. The parameters of the local environment of titanium, copper, and chromium atoms in the structures of the samples under study are calculated. It is established that the presence of a copper impurity in the coating of no more than 12% in amount leads to a slight increase in the Ti–N distance in comparison with the titanium sample, whereas doping with silicon leads, on the contrary, to a decrease in the bond length. The measurement results for the K absorption edges of copper and chromium confirm that the doping elements are concentrated at the edges of the growing titanium-nitride crystallite and determine its size, which corresponds to the sizes of the coherent-scattering region of 40–50 nm.

X-ray transition radiation of electrons with energy of 300 to 900 MeV in periodic multifoil radiators

Results of experiments conducted at the Tomsk synchrotron to study resonant X-ray transition radiation generated by relativistic electrons in periodic multifoil radiators are reviewed. Both the internal synchrotron beam and the external secondary electron beam from the pair magnetic γ-spectrometer with energies ranging from 300 to 900 MeV were used in the experiments. The radiators consisted of many thin amorphous foils of various materials. The generation of X-ray radiation in a compound radiator consisting of a multifoil radiator and a crystal is also studied. In this case, the resonant X-ray transition radiation generated in the multifoil radiator is diffracted in the crystal and emitted at Bragg angles, together with the parametric X-ray radiation generated in the crystal. Spectral and angular properties of the resonant X-ray transition radiation and diffracted resonant X-ray transition radiation are investigated. The ratio between the contributions from the diffracted resonant X-ray transition radiation and other types of radiation to the total coherent X-ray radiation flux generated by electrons in periodic structures and crystals is estimated.

Manufacturing of regular microstructures by methods of LIGA — Technologies

The results of the work on the creation of regular microstructures using deep x-ray lithography with synchrotron radiation are presented. The characteristics of the main processes of supporting membranes formation, absorbing layers and topological templates, as well as the results of measurements of the resulting structures when exposed to the channel of synchrotron radiation are presented.

Soft x-ray radiation on the microtron electron beam

The first results of experimental study of a back transition radiation (BTR) generated by 5.7 MeV electrons in the soft x-ray radiation region are presented. In the experiment the angular distribution (rocking curves) of the yield of radiation generated at the input surfaces of the samples has been measured for thin Si crystal. The radiation was measured by a channel electron multiplier (CEM-6) at the angle θD = 60° with respect to the electron beam direction. The experimental results and the method of extraction of the DTR and PXR contributions are discussed and are compared with the theory. For estimation of the radiation energy structure and the background level are used super thin filters. The analysis of the results testified, that main contributions in the radiation yield depend from the 10-30 eV photons emission.

Monochromatization of Bremsstrahlung radiation of 5,7 MeV electrons in a thin amorphous target

In recent years the cyclic electron accelerators with energy less than 50 MeV for generation of intensive gamma beams are supported to be used in some works. The increasing of transformation ratio of electron energy into energy of electromagnet radiation [1-3] is achieved by multiple accelerated electron penetration through the superthin amorphous target