Yu. A. Bashmakov

Generation of X-ray radiation during planar channeling of relativistic electrons in crystals

A classical model of the emission of radiation by relativistic electrons in a crystal has been developed using the form of the potential maximally close to its actual form. The dynamics of electrons with energies 20–25 MeV performing channeling in crystals is simulated numerically. The generation of electromagnetic radiation that accompanies this motion has been considered. It has been shown that, in the given electron energy range, this radiation corresponds to the X-ray spectral band with characteristic photon energies of up to 40 keV. The radiation yield is estimated. The requirements to the electron beam parameters are formulated based on the results of the simulation. It has been shown that numerical simulation gives results that correlate with the analytic results obtained earlier and with the experimental data.

Radiation source for medical X-ray examination, based on the use of electron radiation during channeling in crystals

One of the possible applications of relativistic electron radiation during channeling in crystals, i.e., the use of radiation for medical visualization, is considered.A setup scheme is proposed, the results of numerical simulation of electron dynamics in crystals and radiation generation and the results of calculations of dose loads are presented.

Radiation and spin separation of high energy positrons by bent crystal

The channeling of ultrahigh energy positrons both in bent and straight crystals can serve as an effective source of hard photons. The presence in the channel of the strong inhomogeneous electrical field gives rise to a number of interesting peculiarities of the motion of the channeling particles. The radiative separation of particles depending on spin orientation with respect to the plane of motion and radiative polarization can make it possible to obtain by means of bent crystals a positron beam with a degree of polarization about 10 to 20%. Because of availability of the ultrahigh energy positron beams such experiments can be carried out nowadays.

An Electromagnetic Calorimeter with a Transversal Orientation of the Scintillating Fibers

The space and energy resolutions of the SPACAL electromagnetic calorimeter with a transverse orientation of the scintillating fibers have been measured. The main parameters of the calorimeter are presented. The results of experiments with an electron test beam of the DESY synchrotron at energies E = 1–6 GeV are discussed. The measured energy resolution of the calorimeter is found to be (σ/E) = 12.7%/√E ⊕ 2.0% (E is expressed in terms of GeV), and the space resolution is σx, y(E) = 1 mm at E = 4 GeV.