Tomography as a diagnostic tool for phase space mapping of intense particle beams

D Stratakis,M Reiser,B Quinn,H Li,S Bernal,P G O’Shea,R A Kishek,M Walter

doi:10.1103/physrevstab.9.112801

Abstract

A technique is described for the tomographic mapping of transverse phase space in beams with space charge. Most prior studies where performed at high energy where space charge was negligible and therefore not considered in the analysis. The tomographic reconstruction process is compared with results of simulations using the particle-in-cell code WARP. The new tomographic technique is tested for beams with different intensities (both emittance and space-charge dominated), and with different initial distributions. Effects of various errors in the data collection process on the reconstructed phase space are discussed. It is shown that the crucial factor is not necessarily the number of projections but the range of angles over which the projections are taken. This study also includes a number of experimental results on tomographic phase space mapping performed on the University of Maryland Electron Ring.

Highlights

Intense particle beams have applications in many different research areas which impact our lives
How accurate is the filtered-backprojection algorithm (FBA) algorithm? How many projections are needed? What happens when the phase space rotation is less than 180? How sensitive is the reconstruction to uncertainties in the input parameters? To answer such questions we model a quadrupole scan for a low current electron beam and follow the process described in Sec
The validity of our reconstructed phase space was tested by comparing our results to the phase space generated directly by WARP which is highly accurate since it is not making the assumptions that our tomography algorithm does

Summary

Introduction

Intense particle beams have applications in many different research areas which impact our lives Such applications of intense beams include accelerator-driven neutron sources [1], higher-luminosity high-energy colliders, free electron lasers (FEL) [2], and heavy-ion inertial fusion drivers (HIF) [3]. Heavy-ion inertial fusion drivers promise the production of large and unlimited amounts of energy which can be harnessed to provide an affordable and environmentally attractive source of electrical power. All these applications are premised on the considerable challenge of generating, transporting, accelerating, and focusing large amounts of particles confined in a narrow region of phase space, without significant particle losses or deterioration of beam quality. One nanocoulomb of charge confined into a 300 fs bunch (line charge density equal to 11 C=m) with 1 m transverse normalized emittance are typical parameters for such beams, with HIF drivers demanding much more charge per bunch

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Conclusion