Correlations between X-rays, Visible Light and Drive-Beam Energy Loss Observed in Plasma Wakefield Acceleration Experiments at FACET-II

TL;DR

This paper reports on correlations observed between X-ray emissions, visible light, and energy loss in plasma wakefield acceleration experiments, suggesting these signals can serve as non-invasive diagnostics for energy transfer monitoring.

Contribution

It establishes the linear correlation between X-ray signals and energy transfer metrics, demonstrating their potential as diagnostic tools in plasma wakefield acceleration.

Findings

X-ray signals correlate linearly with drive beam energy loss.

Visible plasma light indicates wake presence at multiple locations.

X-ray and visible light emissions can monitor energy transfer non-invasively.

Abstract

This study documents several correlations observed during the first run of the plasma wakefield acceleration experiment E300 conducted at FACET-II, using a single drive electron bunch. The established correlations include those between the measured maximum energy loss of the drive electron beam and the integrated betatron x-ray signal, the calculated total beam energy deposited in the plasma and the integrated x-ray signal, among three visible light emission measuring cameras, and between the visible plasma light and x-ray signal. The integrated x-ray signal correlates almost linearly with both the maximum energy loss of the drive beam and the energy deposited into the plasma, demonstrating its usability as a measure of energy transfer from the drive beam to the plasma. Visible plasma light is found to be a useful indicator of the presence of wake at three locations that overall are two meters apart. Despite the complex dynamics and vastly different timescales, the x-ray radiation from the drive bunch and visible light emission from the plasma may prove to be effective non-invasive diagnostics for monitoring the energy transfer from the beam to the plasma in future high-repetition-rate experiments.