Search

A new method for the experimental study of ionization loss of relativistic negatively charged particles moving in a crystal in the channeling regime using a semiconductor surface-barrier detector with smoothly tunable thickness of the depleted layer is proposed. The ionization loss can only be measured in the depleted layer of the detector. The thickness of the depleted layer in a flat semiconductor detector can be smoothly regulated by the value of the bias voltage of the detector. Therefore, the energy distribution of the ionization loss of relativistic particles which cross the detector and move in the channeling regime in the detector crystal can be measured along the path of the particles at variation of the bias voltage of the detector. Ionization loss spectra should be different for channeling and nonchanneling particles, and both fractions can be determined. The application of a Si surface-barrier detector-target is considered. Measurements with such a detector would make it possible to study: the energy distribution of ionization loss of channeling negatively and positively charged particles; spatial distribution of ionization loss as a function of the path length of channeling particles; the dechanneling length of negatively charged particles; and to clear up the role of rechanneling of the particles in the crystal. Comparison of experimental data with calculations can help to develop a description of the dynamics of motion of negatively charged particles channeling in a crystal. A better understanding of the dechanneling length properties can be useful in the production of positrons and other particles such as neutrons by an electron beam in crystals, and in the development of crystalline undulators, and at a crystal-based extraction of electron beams from a synchrotron., 9 pages, 1 figure

The reports collected in these proceedings have been presented in the third French-Ukrainian workshop on the instrumentation developments for high-energy physics held at LAL, Orsay on October 15-16. The workshop was conducted in the scope of the IDEATE International Associated Laboratory (LIA). Joint developments between French and Ukrainian laboratories and universities as well as new proposals have been discussed. The main topics of the papers presented in the Proceedings are developments for accelerator and beam monitoring, detector developments, joint developments for large-scale high-energy and astroparticle physics projects, medical applications., 3rd French-Ukrainian workshop on the instrumentation developments for High Energy Physics, October 15-16, 2015, LAL, Orsay, France, 94 pages

An idea of producing a focused parametric X-ray radiation (PXR) is presented. The PXR is emitted by relativistic charged particles channeling along a bent crystal. Then the PXR emitted from the whole length of the bent crystal is going to the focus. Some properties of focused PXR are estimated for typical experimental conditions and possible applications are discussed. The experiment for observation of focused PXR is proposed., 8 pages, including 1 figure

It is shown that the diffraction on a polycrystal can be used for investigation and diagnostics of X-ray radiation emitted in a forward direction by relativistic charged particles moving in crystalline or other targets or fields. Methods for measuring radiation spectral density, divergence, and linear polarization at any requisite energy from a few units to tens of keV are proposed. The explanation for the origination of experimentally observed and earlier unidentified spectral peaks as a result of Bragg diffraction on a polycrystal is described. The experiment for verification of the explanation is suggested., 7 pages, 1 figure

Journal of physics / B 54(4), 045201 (1-7) (2021). doi:10.1088/1361-6455/abd961, The K-shell ionization cross sections of titanium and copper atoms were determined by analyzing the spectra of characteristic X-ray radiation generated by an electron beam with energies of 1 and 2 GeV in metal foils. New data obtained for these energies demonstrate the influence of the density effect on the ionization cross sections values. The results were compared with previous experimental data and calculations based on pure theoretical and semi-empirical models., Published by IOP Publ., Bristol