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Title: High resolution phase space measurements with Allison-type emittance scanners

Abstract

Allison-type emittance scanners are widely used to measure projected 2D phase space distributions of low energy beams. This paper extends the conventional data analysis model to introduce three significant corrections that commonly arise in the pursuit of high resolution measurements. First, effective longitudinal asymmetry in the E-dipole placement (typically resulting from directional choice of relief cuts in thick slit-plates) causes deviation from the ideal voltage-to-angle conversion relation. Second, finite slit thickness generates variation in weights of data points that should be compensated. Third, when the interval between data points is smaller than the device resolution (ordinary in the angular data accumulation), a detailed account of the phase space region contributing to each data point can be used to resolve the beam distribution more accurately. These findings are illustrated by simulations with numerically generated phase space distributions. The improved model is applied to experimental measurements of an Ar ion beam with an Allison scanner operating at the front-end of the Facility for Rare Isotope Beams (FRIB) at Michigan State University. Results show that the improved model obtains better agreement among a set of measurements and modifies beam moments significantly (can be ~ 10 % relative to conventional methods, with larger deviationsmore » at increasing angular divergence), thus rendering the corrections important for accurate high resolution phase-space characterizations. Python code tools that implement the improved analysis described are made available. These tools are readily applicable to any Allison scanner given a specification of the device geometry and scan ranges associated with each measurement.« less

Authors:
; ;
Publication Date:
Research Org.:
Michigan State Univ., East Lansing, MI (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Nuclear Physics (NP); National Science Foundation (NSF)
OSTI Identifier:
1530639
Alternate Identifier(s):
OSTI ID: 1610443
Grant/Contract Number:  
SC0000661; PHY-1565546
Resource Type:
Published Article
Journal Name:
Physical Review Accelerators and Beams
Additional Journal Information:
Journal Name: Physical Review Accelerators and Beams Journal Volume: 22 Journal Issue: 7; Journal ID: ISSN 2469-9888
Publisher:
American Physical Society (APS)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; Physics

Citation Formats

Wong, Jonathan C., Lund, Steven M., and Maruta, Tomofumi. High resolution phase space measurements with Allison-type emittance scanners. United States: N. p., 2019. Web. doi:10.1103/PhysRevAccelBeams.22.072801.
Wong, Jonathan C., Lund, Steven M., & Maruta, Tomofumi. High resolution phase space measurements with Allison-type emittance scanners. United States. doi:10.1103/PhysRevAccelBeams.22.072801.
Wong, Jonathan C., Lund, Steven M., and Maruta, Tomofumi. Tue . "High resolution phase space measurements with Allison-type emittance scanners". United States. doi:10.1103/PhysRevAccelBeams.22.072801.
@article{osti_1530639,
title = {High resolution phase space measurements with Allison-type emittance scanners},
author = {Wong, Jonathan C. and Lund, Steven M. and Maruta, Tomofumi},
abstractNote = {Allison-type emittance scanners are widely used to measure projected 2D phase space distributions of low energy beams. This paper extends the conventional data analysis model to introduce three significant corrections that commonly arise in the pursuit of high resolution measurements. First, effective longitudinal asymmetry in the E-dipole placement (typically resulting from directional choice of relief cuts in thick slit-plates) causes deviation from the ideal voltage-to-angle conversion relation. Second, finite slit thickness generates variation in weights of data points that should be compensated. Third, when the interval between data points is smaller than the device resolution (ordinary in the angular data accumulation), a detailed account of the phase space region contributing to each data point can be used to resolve the beam distribution more accurately. These findings are illustrated by simulations with numerically generated phase space distributions. The improved model is applied to experimental measurements of an Ar ion beam with an Allison scanner operating at the front-end of the Facility for Rare Isotope Beams (FRIB) at Michigan State University. Results show that the improved model obtains better agreement among a set of measurements and modifies beam moments significantly (can be ~ 10 % relative to conventional methods, with larger deviations at increasing angular divergence), thus rendering the corrections important for accurate high resolution phase-space characterizations. Python code tools that implement the improved analysis described are made available. These tools are readily applicable to any Allison scanner given a specification of the device geometry and scan ranges associated with each measurement.},
doi = {10.1103/PhysRevAccelBeams.22.072801},
journal = {Physical Review Accelerators and Beams},
number = 7,
volume = 22,
place = {United States},
year = {2019},
month = {7}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record
DOI: 10.1103/PhysRevAccelBeams.22.072801

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Works referenced in this record:

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