The report will provide an overview of a number of radiation processes involving
twisted particles, that is, particles with a non-zero projection of the orbital angular momentum on the direction of motion of a particle.
In this talk I review the basic properties of twisted particles and unusual properties of many atomic processes with twisted particles (new selection rules, unusual angular...
Vortex electrons are freely propagating particles that carry orbital angular momentum (OAM) ℓ with respect to a propagation axis and its values, obtained experimentally, already reach ℓ ~ 1000 ℏ. In contrast to the ordinary beams, such twisted electrons possess an additional magnetic moment, an electric quadrupole moment, as well as higher multipole moments. These moments can be controlled by...
We review the process of photon emission by a relativistic electron moving along a classical trajectory in an external field.
In a first part we assume that the emitted photon energy is much smaller than the electron energy. This case can be treated in classical electrodynamics. We briefly review the main radiation characteristics: spontaneous or stimulated emission, dipolar or...
Applied research planned at the accelerator complex NICA is discussed. This research includes radiobiology, material research, testing of electronic components, etc. Beam monitoring and methodology of experimetnal studies are discussed. The self-similarity approach is applied to demonstrate the attractiveness of experiments in the intermediate energy range.
oday, third- and fourth-generation synchrotron radiation (SR) sources and X-ray free-electron lasers (FEL's) find many different applications in materials science, molecular biology and biochemistry, biomedical studies, crystallography, spectroscopy, studies of rapid processes and other areas of scientific and applied research. For these applications the crucial problem consists in reaching...
We report the results of experimental and theoretical studies of coherent terahertz radiation generated by a short electron bunch from a metasurface. The metasurface is an array of sub-wavelength copper spherical-like elements placed on a monocrystalline sapphire substrate. The target has two periodicities, along and perpendicular to the electrons trajectory. Experiment was carried out using 8...
Usually the ionization loss of a beam moving in substance is just a sum of independent losses of separate particles constituting the beam. In the present work it is shown that for beams (bunches) of sufficiently high particle density and small spatial size this rule can be considerably violated. In this case the value of the bunch ionization loss can exceed the above sum by several orders of...
Optical Transition Radiation (OTR) is widely used for transverse beam profile diagnostics at electron linear accelerators. But this technique may not be implemented for FEL’s [1] or LWPA accelerators [2], the reason is that such machines have ultrashort bunches causing coherent effects in the OTR emission process [3]. An approach to calculate the coherent OTR (COTR) propagation through a...
Compton backscattering is the most promising instrument of radiation generation in the X-ray range. Comparing with modern 4-th generation facilities, Compton sources offer very important for the research laboratories advantages – relative compactness and cheapness, while the main characteristics (number of photons per pulse, energy bandwidth, pulse duration, emittance etc.) can be sufficient...
To characterize fast charged particle scattering on an atom, two parameters are introduced, depending on the atom potential and determining the hard scattering (pre-Rutherford asymptotic behavior), and one parameter characterizing multiple scattering in atomic matter from such atoms. It is proven that the latter quantity expresses the screening momentum in the Molière’s multiple Coulomb...
N.P. Kalashnikov (kalash@mephi.ru), А.S. Olchak (asolchak@mephi.ru)
National Nuclear Research University «MEPhI» (Moscow Engineering Physics Institute)
115409 Moscow, Kashirskoe shosse, 31, Russia
Abstract
Interaction of relativistic electrons with crystal axis or plane is traditionally described in channeling model as a motion in some even, homogeneous averaged potential. However, real...
Nowadays the Baier-Katkov (BK) semiclassical method [1] is a standard tool to describe radiation of plane wave photons by ultrarelativistic charged particles in external electromagnetic fields of a general form. The BK method is realized in several computer codes [2,3] and proved to be very successful. We use this method to derive the radiation probability of one twisted photon [4] by an...
The relativistic nature of phenomena is illustrated in terms of the Lobachevsky geometry. The Lobachevsky space is used for description of particle production in relativistic nuclear physics on the basis of experimental data obtained at bubble chambers in pi-C, p-C, C-C, n-p reactions in an energy range from units to tens of GeV. The new phenomenon - directed nuclear radiation - is discussed.
