Multi-component measurements of the Jefferson Lab energy recovery linac electron beam using optical transition and diffraction radiation

TL;DR

This paper demonstrates the use of optical transition and diffraction radiation techniques to analyze complex electron beam distributions in a Jefferson Lab energy recovery linac, revealing two distinct components and estimating their emittances.

Contribution

It introduces diagnostic experiments using OTR and ODR at a high-energy ERL to identify multiple beam components and estimate their emittance values.

Findings

Detection of two separate beam components

Estimation of rms emittance for each component

Validation of optical diagnostics for complex beam analysis

Abstract

High brightness electron accelerators, such as energy recovery linacs (ERL), often have complex particle distributions that can create difficulties in beam transport as well as matching to devices such as wigglers used to generate radiation from the beam. Optical transition radiation (OTR), OTR interferometry (OTRI) and optical diffraction-transition radiation interferometry (ODTRI) have proven to be effective tools for diagnosing both the spatial and angular distributions of charged particle beams. OTRI and ODTRI have been used to measure rms divergences and optical transverse phase space mapping has been demonstrated using OTRI. In this work we present the results of diagnostic experiments using OTR and ODR conducted at the Jefferson Laboratory 115 MeV ERL which show the presence of two separate components within the spatial and angular distributions of the beam. By assuming a correlation between the spatial and angular features we estimate an rms emittance value for each of the two components.