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

## TL;DR

This paper introduces a novel single-shot measurement technique using a dipole magnet spectrometer with scintillation screens, enabling precise spectral characterization of GeV electron beams from laser wakefield accelerators, even with beam fluctuations.

## Contribution

The paper presents an optimized algorithm and numerical code for accurate, single-shot spectral measurement of LWFA electron beams, validated through simulations and applied to multi-GeV experiments.

## Key findings

- Enhanced accuracy in spectral measurement of LWFA electron beams.
- Effective characterization despite shot-to-shot pointing fluctuations.
- Successful application to multi-GeV electron beams from high-power lasers.

## 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 tracing 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 improved accuracy to faithfully characterize electron beams with non-negligible shot-to-shot beam pointing fluctuations, particularly in the state-of-the-art multi-GeV LWFA experiments performed to push the energy frontier.

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Source: https://tomesphere.com/paper/1907.02239