Observation of acceleration and deceleration in gigaelectron-volt-per-metre gradient dielectric wakefield accelerators.

B D O’Shea,P D Hoang,V Yakimenko,S Hakimi,M J Hogan,K L Fitzmorris,S K Barber,J B Rosenzweig,B Naranjo,J Harrison,O B Williams,G Andonian

doi:10.1038/ncomms12763

Abstract

There is urgent need to develop new acceleration techniques capable of exceeding gigaelectron-volt-per-metre (GeV m−1) gradients in order to enable future generations of both light sources and high-energy physics experiments. To address this need, short wavelength accelerators based on wakefields, where an intense relativistic electron beam radiates the demanded fields directly into the accelerator structure or medium, are currently under intense investigation. One such wakefield based accelerator, the dielectric wakefield accelerator, uses a dielectric lined-waveguide to support a wakefield used for acceleration. Here we show gradients of 1.347±0.020 GeV m−1 using a dielectric wakefield accelerator of 15 cm length, with sub-millimetre transverse aperture, by measuring changes of the kinetic state of relativistic electron beams. We follow this measurement by demonstrating accelerating gradients of 320±17 MeV m−1. Both measurements improve on previous measurements by and order of magnitude and show promise for dielectric wakefield accelerators as sources of high-energy electrons.

Highlights

There is urgent need to develop new acceleration techniques capable of exceeding gigaelectron-volt-per-metre (GeV m À 1) gradients in order to enable future generations of both light sources and high-energy physics experiments
High-energy physics require ever increasing beam energies to reach the frontiers of new science
Given the expanded operating wavelength used in THz dielectric wakefield accelerator (DWA), transport issues associated with DLA apertures are avoided

Summary

Introduction

There is urgent need to develop new acceleration techniques capable of exceeding gigaelectron-volt-per-metre (GeV m À 1) gradients in order to enable future generations of both light sources and high-energy physics experiments. To address this need, short wavelength accelerators based on wakefields, where an intense relativistic electron beam radiates the demanded fields directly into the accelerator structure or medium, are currently under intense investigation. A wakefield based accelerator is a system in which an intense charged particle beam directly excites accelerating fields in a slow-wave, phase velocity vphoc, structure or medium This allows for the generation of large accelerating fields at wavelengths where no traditional power source exists. While DWA15 have shown structure breakdown accelerating field limits[16] in excess of 5 GV m À 1, acceleration gradients in excess of 69 MeV m À 1 have not yet been demonstrated[17,18,19]

Methods

Results

Conclusion