TUPSB23
MEPhI, Moscow, Russia
BNRU, Belgorod, Russia
NRC, Moscow, Russia
Thomson (or, in the quantum regime, Compton) backscattering occurs when a beam of charged par-ticles collides with the laser pulse, and so the electrons oscillate in the periodic field of the electromag-netic wave, what is called light or laser undulator. This radiation source is a modern and promising in-strument for generation of X-ray radiation. While Thomson sources are compact and comparatively cheap, their main characteristics (number of photons per pulse, energy bandwidth, pulse duration, emit-tance etc.) can be sufficient for applications in phase contrast and K-edge imaging, cancer therapy, computed tomography and so on. In this report we describe briefly the current state of development of such sources. We discuss the theoretical approach describing the interaction of electron beams with electromagnetic waves, advantages and disadvantages of linear and nonlinear regimes, coherent effects in radiation from short bunches, including sub-picosecond ones, as well as the new trends in this field, as a growing interest to the radiation of attosecond relativistic electron bunches.
MEPhI, Moscow, Russia
BelSU/LRP, Belgorod, Russia
NRC, Moscow, Russia
BNRU, Belgorod, Russia
Being a compact source of x-rays based on the Thomson backscattering Thomson source has potential to be used in medicine and biology and in other area where narrow band x-ray beams are essential. We suggest and investigate theoretically the idea to use laser pulses modulated with a short period in Thomson backscattering. The coherent radiation is obtained with intensity proportional to the squared number of micro-pulses in the whole laser pulse.
MEPhI, Moscow, Russia
NRC, Moscow, Russia
BNRU, Belgorod, Russia
BelSU/LRP, Belgorod, Russia
Compton backscattering* is a promising mechanism for engineering of a bright, compact and versatile X-ray source: with dimensions being significantly smaller, the brightness of this source is comparable with that of synchrotron radiation. Nowadays, active researches are underway on various aspects of this phenomenon** aiming at increasing of radiation intensity and quality. In modern science, such kind of research is necessarily accompanied by the computer simulations. In this report, we are talking about creation and implementation of the Compton backscattering module into the Geant4 package***, which is the leading simulation toolkit in high-energy physics, accelerator physics, medical physics, and space studies. Created module of Compton backscattering has been implemented as a discrete physical process and operates with a fixed light target (a virtual volume with the properties of a laser beam), with which a beam of charged particles interacts. Such a description allows user to flexibly change necessary parameters depending on the problem being solved, which opens up new possibilities for using Geant4 in the studied area.
* K.T. Phuoc et al., Nat. Photonics 6, 308 (2012).
** A. Ovodenko et al., Appl. Phys. Lett. 109, 253504 (2016).
*** S. Agostinelli et al., Nucl. Instrum. Meth. A 506, 250 (2003).
WED07
MEPhI, Moscow, Russia
NRC, Moscow, Russia
BNRU, Belgorod, Russia
Smith-Purcell radiation (SPR) is generated when an electron beam passes near a diffraction grating. Contrary to other methods (scintillator and transition radiation screens, wire scanners, etc.) SPR is not accompanied by the scattering of the beam¿s electrons on the target. This unique feature lets SPR provide non-destructive diagnostics of relativistic electron beams in linacs, including single shot measurements. Beam diagnostics is carried out by comparing experimental data with theoretical ones* and the following extraction of the beam parameters. Existing theoretical models are valid in the wave zone (but for the only exception of qualitative estimates in **), i.e. the detector must be placed at the distances much more than the wavelength of radiation multiplied by gamma2, where gamma is the Lorentz factor of the electrons. For ultrarelativistic beams (e.g., gamma = 100) the wave zone starts from 10 meters or more for the wavelength in mm and sub-mm ranges, which is completely out of realistic experimental conditions. Therefore, theory in prewave zone is needed. In this paper we solve this problem, developing the results published recently in ***. We analyze the radiation characteristics and also discuss how to use the results for the relativistic beam diagnostics.
*H.L. Andrews, et al., Phys. Rev. STAB 17, 052802 (2014).
**D.V. Karlovets, A.P. Potylitsyn, JETP Letters 84, 579 (2006).
***D.I. Garaev, et al., Phys. Rev. B 103, 075403 (2021).
