| Paper |
Title |
Page |
| TUAX01 |
Accumulation of High Intensity Beam and First Observations of Instabilities in the SNS Accumulator Ring*
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59 |
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- V. V. Danilov, A. V. Aleksandrov, S. Assadi, W. Blokland, S. M. Cousineau, C. Deibele, S. Henderson, J. A. Holmes, M. A. Plum, A. P. Shishlo
ORNL, Oak Ridge, Tennessee
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The Spallation Neutron Source accumulator ring, designed to accumulate up to 1.5·1014 protons per pulse, was commissioned in January of 2006. During the run, over 1.·1014 protons were accumulated in the ring in the natural chromaticity state without any sign of instabilities. The first beam instabilities were observed for a high intensity coasting beam with zero chromaticity. Preliminary analysis of data indicates instabilities related to extraction kicker impedances, and electron-proton instability. Here we review the background theory and design philosophy of the ring, as it relates to instabilities, and compare the pre-commissioning predictions with the experimental measurements.
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| TUAX04 |
Test of a prototype active damping system for the e-p instability at the LANL PSR
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94 |
| |
- R. J. Macek, R. C. McCrady, S. B. Walbridge, J. Zaugg
LANL, Los Alamos, New Mexico
- S. Assadi, C. Deibele, S. Henderson, M. A. Plum
ORNL, Oak Ridge, Tennessee
- J. M. Byrd
LBNL, Berkeley, California
- M. T.F. Pivi
SLAC, Menlo Park, California
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Our collaboration from LANL, SNS, LBNL and SLAC has developed and successfully tested a prototype of an analog, transverse (vertical) feedback system for active damping of the two-stream (e-p) instability at the Los Alamos Proton Storage Ring (PSR). This system was able to improve the instability threshold (as measured by the RF buncher voltage) by ~30%. Beam leakage into the gap at lower RF buncher voltage and resulting higher growth rates from more trapped electrons is the likely cause of this limitation. We will describe the system configuration and results of several experimental tests of system performance. We will also discuss our studies and analysis of the factors limiting system performance.
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