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A. A. Tishchenko

Publications and source records attributed to A. A. Tishchenko.

5 recordsLinked to original sources

Electron beam evolution in a successive Compton backscattering

Inverse Compton scattering (ICS) is a unique source of highly monochromatic x-ray and gamma radiation. We investigate theoretically the cumulative effects of repeated head-on interactions between the electron beam and a train of powerful laser pulses inside a linear accelerating structure placed between mirrors of an optical resonator. We find that the longitudinal momentum spread converges exponentially to an equilibrium value due to the competition between quantum excitation (heating) and radiation friction (cooling). The predictions of the developed theory coincide very well with computer simulations. Our work establishes the necessity to account for cumulative transverse beam dynamics in the design and optimization of future stable, high-brightness ICS sources.

physics.acc-ph

Detecting Hollow Electron Beams via Smith-Purcell Radiation from a Metasurface

Hollow electron beams are today highly desirable for many applications, but are still challenging in view of their detection. In this Letter, we focus on the unique character of the electromagnetic radiation that relativistic hollow electron beams can produce when traveling above a metasurface. We investigate theoretically the specific features of the radiation in a coherent mode, which provides the highest intensity, and show that the radiation from a hollow beam can be considerably more intense than that from a conventional solid beam. This solves the problem of distinguishing between hollow and solid beams. Moreover, we consider the two-layer internal structure of a hollow beam and reveal that the radiation characteristics are sensitive to the width and population of each layer. This allows detecting the internal structure of hollow beams. Interestingly, we found that the factor describing the annular beam form is a separated multiplier in a conventional form factor, independent of the properties of periodic structure. Thus, we can conclude that our results will stay correct for different profiles of periodic structures and metasurfaces made of metaatoms of different topologies and forms. The results pave the way towards a variety of newly emerging applications based on hollow electron beams, very diverse in topics, such as manipulation of objects at the nano-level, studies of chiral matter, plasma acceleration in donut wakefields and even applications in huge facilities such as LHC for controlling proton beam halos etc.

physics.optics

Identification of particles with Lorentz factor up to $10^{4}$ with Transition Radiation Detectors based on micro-strip silicon detectors

This work is dedicated to the study of a technique for hadron identification in the TeV momentum range, based on the simultaneous measurement of the energies and of the emission angles of the Transition Radiation (TR) X-rays with respect to the radiating particles. A detector setup has been built and tested with particles in a wide range of Lorentz factors (from about $10^3$ to about $4 \times 10^4$ crossing different types of radiators. The measured double-differential (in energy and angle) spectra of the TR photons are in a reasonably good agreement with TR simulation predictions.

physics.ins-det

Sub - THz Radiation from Dielectric Capillaries with Reflectors

In this report we present experimental investigations of THz radiation generated from a corrugated and a non-corrugated capillary with reflectors, using a femtosecond electron beam of LUCX accelerator at KEK, Japan. We discuss measurements of radiation angular distributions and their comparison with Particle In Cell simulations, and also investigate an off-central propagation of the beam in the capillaries based on experimental measurements and simulations.

physics.acc-ph

Geant4 simulations of the lead fluoride calorimeter

In this paper we simulate the emission by charged particles in complex structures with help of Geant4. We take into account Cherenkov radiation, transition radiation, bremsstrahlung, pair production and other accompanying processes. As an application we investigate the full size electromagnetic calorimeter for the muon g-2 experiment at Fermilab. A calorimeter module (24 are expected in the experiment) consists of a Delrin front panel for installation of the laser calibration system, 54 PbF2 Cherenkov crystals wrapped by the black Millipore paper, and silicon photo-multiplier sensors. We report here on a simulation of radiation from positrons passing through the calorimeter system. We carry out the simulation using Geant4 toolkit, which provides a complete set of tools for all areas of detector simulation: geometry, tracking, detector response, run, event and track management, and visualization. We consider Cherenkov photons expansion when a positron moves down through the calorimeter at the arbitrary angle of incidence. Both spectral and angular distributions of Cherenkov optical photons in different parts of the calorimeter system have been evaluated as well as the transition radiation and pre-shower distributions from the panel and from the Al vacuum chamber of the storage ring. (The paper is in progress).

physics.acc-ph