Ultrashort electron bunch length measurement with diffraction radiation deflector

Dao Xiang,Wen-Hui Huang

doi:10.1103/physrevstab.10.012801

Dao Xiang, Wen-Hui Huang

Open Access

https://doi.org/10.1103/physrevstab.10.012801

Copy DOI

Abstract

In this paper, we propose a novel method to measure electron bunch length with a diffraction radiation (DR) deflector which is composed of a DR radiator and three beam position monitors (BPMs). When an electron beam passes through a metallic aperture which is tilted by 45 degrees with respect to its trajectory, backward DR that propagates perpendicular to the beam's trajectory is generated which adds a transverse deflection to the beam as a result of momentum conservation. The deflection is found to be largely dependent on the bunch length and could be easily observed with a downstream BPM. Detailed investigations show that this method has wide applicability, high temporal resolution, and great simplicity.

Highlights

There are growing interests in generation, measurement, and applications of short electron beam with energy ranging from a few MeV to hundreds of GeV
When the electron beam passes through the diffraction radiation (DR) radiator with inner radius 0.5 mm and outer radius 30 mm, the deflection is found to be as large as 0.13 mrad, which is observable even with the common beam position monitors (BPMs)
We proposed a new DR based method for electron bunch length measurement

Summary

INTRODUCTION

There are growing interests in generation, measurement, and applications of short electron beam with energy ranging from a few MeV to hundreds of GeV. In addition to the high temporal resolution, the compatible method should be able to preserve the beam qualities during the measurement, for all these facilities require a low emittance beam. The method is compatible to the facilities mentioned above, for the electron does not hit the radiator directly and the emittance growth due to Coulombic scattering as that suffered in the intercepting method is completely avoided. It is found the deflection is very sensitive to bunch length, which offers a simple method for bunch length determination. The shorter the bunch, the larger the deflection, which makes this method very suitable for short bunch measurement

PRINCIPLES OF DR DEFLECTOR

APPLICATIONS IN BUNCH LENGTH MEASUREMENT

PRACTICAL CONSIDERATIONS

SUMMARY AND CONCLUSIONS