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статья/документ по запросу ресурса "5121"
2001-12-12 Фундаментальные и прикладные физические исследования. 1986–2001 гг.: Сб. тр. / Редкол.: В. Г. Барышевский, С. Н. Сытова, С. А. Максименко и др.; Под ред. В. Г. Барышевского. – Мн.: БГУ, 2001. C.245-259 For a charged particle channeled along a crystal axis or plane the projectile path is
formed by correlated collisions with crystal atoms. The particle moves in a effective potential
obtained by smearing the crystal potential along the crystal axis or plane. This motion is
accompanied by a special type of radiation, so-called channeling radiation. X-ray radiation
from a relativistic oscillator in a crystal is essentially modified under diffraction conditions for
emitted photons. A new diffraction radiation is a result of coherent summation of two processes – photon radiation and photon diffraction. It has been called diffraction radiation of oscillator (DRO).
Though predicted back in 1977, DRO has not so far been observed experimentally.
Its study is of considerable interest, since DRO may find application in treating different effects in the optics of a relativistic emitter moving in refracting media. The possibility
of the DRO experimentally observation by measuring the angular distribution was analyzed. It
was shown that this experiment demanded particle beams of high quality because the radiation
characteristics were very sensitive to the particle beam parameters.
Relativistic oscillator can be formed not only by an unperturbed crystal channel but also
by an external ultrasonic or laser field which subjects to the crystal and forms a bent crystal
channel, that is the relativistic oscillator can be a channeled particle which moves in some electromagnetic undulator.
The high spectral and angular densities of diffraction radiation of oscillator and also narrow spectral and angular widths of radiation reflex give the basis of its application for construction of X-ray coherent radiation source by using relativistic particle beams in crystal. Such system can be considered as a crystal X-ray free electron laser (FEL). The idea of parametric
X-ray generator on the basis of channeled electron (positron) beams was firstly expressed. As it was said above, the radiating oscillator can be formed in different ways. This can be
electrons, channeled in averaged crystallographic potential of plane or axes or oscillator
formed by an external field or moves in electromagnetic undulator. Загрузить:
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