Accurate single-shot measurement technique for the spectral distribution of GeV electron beams from a laser wakefield accelerator

C I Hojbota,B S Rao,Hyung Taek Kim,C Aniculaesei,Jung Hun Shin,Chang Hee Nam

doi:10.1063/1.5117311

C I Hojbota, B S Rao + Show 4 more

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https://doi.org/10.1063/1.5117311

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Abstract

We present a technique, based on a dipole magnet spectrometer containing multiple scintillation screens, to accurately characterize the spectral distribution of a GeV electron beam generated by laser wakefield acceleration (LWFA). An optimization algorithm, along with a numerical code, was developed for trajectory tracking and reconstructing the electron beam angle, divergence, and energy spectrum with a single-shot measurement. The code was validated by comparing the results with the Monte-Carlo simulation of electron beam trajectories. We applied the method to analyze data obtained from laser wakefield acceleration experiments performed using a multi-Petawatt laser to accelerate electron beams to multi-GeV energy. Our technique offers a high degree of accuracy to faithfully characterize electron beams with the nonnegligible shot-to-shot beam pointing fluctuations, particularly in the state-of-the-art multi-GeV LWFA experiments performed to push the energy frontier.

Highlights

In laser wakefield acceleration (LWFA),1 an ultrashort laser pulse drives a nonlinear plasma wave, which in turn can trap and accelerate electrons to energies up to multi-GeV.2,3 Progress in the past decades led to a dramatic increase in the energy and quality of accelerated electron beams
We present a technique, based on a dipole magnet spectrometer containing multiple scintillation screens, to accurately characterize the spectral distribution of a GeV electron beam generated by laser wakefield acceleration (LWFA)
We presented a new method suitable for accurately measuring and calibrating the spectrum of electron beams with pointing fluctuations generated from laser wakefield accelerators

Summary

Introduction

In laser wakefield acceleration (LWFA), an ultrashort laser pulse drives a nonlinear plasma wave, which in turn can trap and accelerate electrons to energies up to multi-GeV. Progress in the past decades led to a dramatic increase in the energy and quality of accelerated electron beams. The recent development of novel techniques, such as multi-staging, tailoring of the density profile of a target, or plasma guiding techniques, offers the opportunities to achieve high-energy high-quality stable electron beams in the near future, potentially complementing established technologies of electron accelerators. Such compact electron accelerators are the focus of intensive research due to their wide range of applications: electron diffraction, generation of coherent X-rays through the operation of free-electron lasers, production of intense gamma-rays from Compton backscattering and exploration of fundamental QED processes in all-optical setups. A method for reconstructing the energy distribution of an electron beam is important for accurate characterization of beam parameters in the multi-GeV region

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