Interference and shadow effects in the production of light by charged particles in optical fibers

NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS

卷:266

Article; Proceedings Paper

Artru, Xavier¹  Ray, Cedric¹ 

[1] Univ Lyon 1, Inst Phys Nucl, CNRS, IN2P3, F-69622 Villeurbanne, France

关键词: particle detector;    beam diagnostics;    optical fibers;    Cherenkov radiation;    Smith-Purcell;    plasmon;   

DOI  :  10.1016/j.nimb.2008.03.083

来源: Elsevier

【 摘 要 】

A charged particle passing through or near a narrow optical fiber induces, by polarisation, coherent light guided by the fiber. In the limit of zero crossing angle, the radiation tends towards a Cherenkov radiation with a discrete spectrum, studied by different authors. If the particle crosses a bent fiber at regularly spaced points, interference gives quasi-monochromatic lines. If the particle passes near an end of the fiber, light is produced by the capture of virtual photons through the end face. An alternative way consists in sticking a metallic ball to the fiber: the passing particle induces plasmons which are then evacuated as light in the fiber. Interferences can occur between lights from several ends or balls. Applications of these various light signals to beam diagnostics are discussed. The shadow effect, which reduces the photon yield when the particle runs parallel to a row of balls, is pointed out and an upper bound -dE/dz <= C(Ze/b)(2) for the particle energy loss is conjectured (Ze is the particle charge, b the impact parameter and C a numerical constant). This bound should also apply to other kinds of light sources, in particular to Smith-Purcell radiation. (C) 2008 Elsevier B.V. All rights reserved.

【 授权许可】

Free