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Title: Measurements of the effective electron density in an electron beam ion trap using extreme ultraviolet spectra and optical imaging

Abstract

In an electron beam ion trap (EBIT), the ions are not confined to the electron beam, but rather oscillate in and out of the beam. As a result, the ions do not continuously experience the full density of the electron beam. To determine the effective electron density, n e,eff, experienced by the ions, the electron beam size, the nominal electron density n e, and the ion distribution around the beam, i.e., the so-called ion cloud, must be measured. We use imaging techniques in the extreme ultraviolet (EUV) and optical to determine these. The electron beam width is measured using 3 d → 3 p emission from Fe xii and xiii between 185 and 205 Å. These transitions are fast and the EUV emission occurs only within the electron beam. The measured spatial emission profile and variable electron current yield a nominal electron density range of n e ~ 10 11–10 13 cm –3. We determine the size of the ion cloud using optical emission from metastable levels of ions with radiative lifetimes longer than the ion orbital periods. Here, the resulting emission maps out the spatial distribution of the ion cloud. We find a typical electron beam radius of ~60more » μm and an ion cloud radius of ~300 μm. These yield a spatially averaged effective electron density, ne,eff, experienced by the ions in EBIT spanning ~ 5 × 10 9–5 × 10 11 cm –3.« less

Authors:
ORCiD logo [1]; ORCiD logo [2];  [2];  [1];  [2];  [2]; ORCiD logo [1]
  1. Columbia Astrophysics Lab, New York, NY (United States)
  2. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1545370
Alternate Identifier(s):
OSTI ID: 1478438
Grant/Contract Number:  
NNX16AF10G; AC52-07NA27344
Resource Type:
Accepted Manuscript
Journal Name:
Review of Scientific Instruments
Additional Journal Information:
Journal Volume: 89; Journal Issue: 10; Journal ID: ISSN 0034-6748
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English

Citation Formats

Arthanayaka, T. P., Beiersdorfer, P., Brown, G. V., Hahn, M., Hell, N., Lockard, T. E., and Savin, D. W. Measurements of the effective electron density in an electron beam ion trap using extreme ultraviolet spectra and optical imaging. United States: N. p., 2018. Web. doi:10.1063/1.5036758.
Arthanayaka, T. P., Beiersdorfer, P., Brown, G. V., Hahn, M., Hell, N., Lockard, T. E., & Savin, D. W. Measurements of the effective electron density in an electron beam ion trap using extreme ultraviolet spectra and optical imaging. United States. doi:10.1063/1.5036758.
Arthanayaka, T. P., Beiersdorfer, P., Brown, G. V., Hahn, M., Hell, N., Lockard, T. E., and Savin, D. W. Mon . "Measurements of the effective electron density in an electron beam ion trap using extreme ultraviolet spectra and optical imaging". United States. doi:10.1063/1.5036758. https://www.osti.gov/servlets/purl/1545370.
@article{osti_1545370,
title = {Measurements of the effective electron density in an electron beam ion trap using extreme ultraviolet spectra and optical imaging},
author = {Arthanayaka, T. P. and Beiersdorfer, P. and Brown, G. V. and Hahn, M. and Hell, N. and Lockard, T. E. and Savin, D. W.},
abstractNote = {In an electron beam ion trap (EBIT), the ions are not confined to the electron beam, but rather oscillate in and out of the beam. As a result, the ions do not continuously experience the full density of the electron beam. To determine the effective electron density, ne,eff, experienced by the ions, the electron beam size, the nominal electron density ne, and the ion distribution around the beam, i.e., the so-called ion cloud, must be measured. We use imaging techniques in the extreme ultraviolet (EUV) and optical to determine these. The electron beam width is measured using 3d → 3p emission from Fe xii and xiii between 185 and 205 Å. These transitions are fast and the EUV emission occurs only within the electron beam. The measured spatial emission profile and variable electron current yield a nominal electron density range of ne ~ 1011–1013 cm–3. We determine the size of the ion cloud using optical emission from metastable levels of ions with radiative lifetimes longer than the ion orbital periods. Here, the resulting emission maps out the spatial distribution of the ion cloud. We find a typical electron beam radius of ~60 μm and an ion cloud radius of ~300 μm. These yield a spatially averaged effective electron density, ne,eff, experienced by the ions in EBIT spanning ~ 5 × 109–5 × 1011 cm–3.},
doi = {10.1063/1.5036758},
journal = {Review of Scientific Instruments},
number = 10,
volume = 89,
place = {United States},
year = {2018},
month = {10}
}

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