Nonintrusive measurement of time-resolved emittances of 1-GeV operational hydrogen ion beam using a laser comb

Y Liu,A Aleksandrov,C Long

doi:10.1103/physrevaccelbeams.23.102806

Y Liu, A Aleksandrov + Show 1 more

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https://doi.org/10.1103/physrevaccelbeams.23.102806

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Abstract

We proposed and demonstrated a novel technique to measure time-resolved transverse emittances of the hydrogen ion (${\mathrm{H}}^{\ensuremath{-}}$) beam in a 1-GeV high-power accelerator. The measurement is performed in a nonintrusive manner by using a laser comb---laser pulses with controllable multilayer temporal structure. The technique has been applied to the transverse emittance measurement of a 1-GeV ${\mathrm{H}}^{\ensuremath{-}}$ beam in the Spallation Neutron Source high energy beam transport line. More than 20 time-resolved emittances have been simultaneously determined within a macropulse, a single minipulse, or a single bunch of the 1.4-MW neutron production ${\mathrm{H}}^{\ensuremath{-}}$ beam from a single measurement.

Highlights

Measurement of transverse phase space distributions is important for improvement of beam matching and control of beam loss in the design and operation of particle accelerators
We experimentally demonstrate for the first time that more than 20 emittance slices within a macropulse, a single minipulse, or a single bunch of the H− beam can be obtained from one measurement
We have described a novel technique of time-resolved emittance measurement of the H− beam by using a laser comb—laser pulses with a controllable multilayer pulse structure

Summary

Introduction

Measurement of transverse phase space distributions is important for improvement of beam matching and control of beam loss in the design and operation of particle accelerators. Conventional transverse phase space measurements use slit-and-collector or pepper-pot approaches [1], both of which intercept the particle beam and cannot be applied to high-power particle beams. The measurement is based on the photodetachment (for ion beam) or the Compton scattering (for electron beam) process. Both processes cause negligible loss to the particle beam and can be applied to the operational beam. All attempts to set up the SNS accelerator in accordance with the model derived parameters, e.g., matching to the design lattice, ended up with high overall beam loss. The current focus of beam diagnostics development at SNS is to help in resolving this discrepancy between the computer modeling and the actual

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