skip to main content

DOE PAGESDOE PAGES

Title: Submacropulse electron-beam dynamics correlated with higher-order modes in Tesla-type superconducting rf cavities

Here, we report the direct observations of submacropulse beam centroid oscillations correlated with higher order modes (HOMs) which were generated by off-axis electron beam steering in TESLA-type superconducting rf cavities. The experiments were performed at the Fermilab Accelerator Science and Technology (FAST) facility using its unique configuration of a photocathode rf gun injecting beam into two separated nine-cell cavities in series with corrector magnets and beam position monitors (BPMs) located before, between, and after them. Oscillations of ~100 kHz in the vertical plane and ~380 kHz in the horizontal plane with up to 600-μm amplitudes were observed in a 3-MHz micropulse repetition rate beam with charges of 100, 300, 500, and 1000 pC/b. However, the effects were much reduced at 100 pC/b. The measurements were based on HOM detector circuitry targeting the first and second dipole passbands, rf BPM bunch-by-bunch array data, imaging cameras, and a framing camera. Calculations reproduced the oscillation frequencies of the phenomena in the vertical case. In principle, these fundamental results may be scaled to cryomodule configurations of major accelerator facilities.
Authors:
 [1] ;  [2] ;  [2] ;  [2] ;  [2] ;  [2] ;  [3] ;  [4] ;  [4]
  1. Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  2. Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
  3. CEA-Saclay, Gif-sur-Yvette (France)
  4. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Publication Date:
Report Number(s):
FERMILAB-PUB-18-044-AD-APC; LA-UR-18-22639
Journal ID: ISSN 2469-9888; PRABCJ; 1677441
Grant/Contract Number:
AC02-07CH11359; 89233218CNA000001
Type:
Published Article
Journal Name:
Physical Review Accelerators and Beams
Additional Journal Information:
Journal Volume: 21; Journal Issue: 6; Journal ID: ISSN 2469-9888
Publisher:
American Physical Society (APS)
Research Org:
Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25); USDOE Laboratory Directed Research and Development (LDRD) Program
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; electron beam; SCRF accelerator; HOMs; beam centroid oscillation; framing camera; Accelerator Design, Technology, and Operations
OSTI Identifier:
1440282
Alternate Identifier(s):
OSTI ID: 1457153; OSTI ID: 1483509

Lumpkin, A. H., Thurman-Keup, R., Edstrom, D., Ruan, J., Eddy, N., Prieto, P., Napoly, O., Carlsten, B. E., and Bishofberger, K.. Submacropulse electron-beam dynamics correlated with higher-order modes in Tesla-type superconducting rf cavities. United States: N. p., Web. doi:10.1103/PhysRevAccelBeams.21.064401.
Lumpkin, A. H., Thurman-Keup, R., Edstrom, D., Ruan, J., Eddy, N., Prieto, P., Napoly, O., Carlsten, B. E., & Bishofberger, K.. Submacropulse electron-beam dynamics correlated with higher-order modes in Tesla-type superconducting rf cavities. United States. doi:10.1103/PhysRevAccelBeams.21.064401.
Lumpkin, A. H., Thurman-Keup, R., Edstrom, D., Ruan, J., Eddy, N., Prieto, P., Napoly, O., Carlsten, B. E., and Bishofberger, K.. 2018. "Submacropulse electron-beam dynamics correlated with higher-order modes in Tesla-type superconducting rf cavities". United States. doi:10.1103/PhysRevAccelBeams.21.064401.
@article{osti_1440282,
title = {Submacropulse electron-beam dynamics correlated with higher-order modes in Tesla-type superconducting rf cavities},
author = {Lumpkin, A. H. and Thurman-Keup, R. and Edstrom, D. and Ruan, J. and Eddy, N. and Prieto, P. and Napoly, O. and Carlsten, B. E. and Bishofberger, K.},
abstractNote = {Here, we report the direct observations of submacropulse beam centroid oscillations correlated with higher order modes (HOMs) which were generated by off-axis electron beam steering in TESLA-type superconducting rf cavities. The experiments were performed at the Fermilab Accelerator Science and Technology (FAST) facility using its unique configuration of a photocathode rf gun injecting beam into two separated nine-cell cavities in series with corrector magnets and beam position monitors (BPMs) located before, between, and after them. Oscillations of ~100 kHz in the vertical plane and ~380 kHz in the horizontal plane with up to 600-μm amplitudes were observed in a 3-MHz micropulse repetition rate beam with charges of 100, 300, 500, and 1000 pC/b. However, the effects were much reduced at 100 pC/b. The measurements were based on HOM detector circuitry targeting the first and second dipole passbands, rf BPM bunch-by-bunch array data, imaging cameras, and a framing camera. Calculations reproduced the oscillation frequencies of the phenomena in the vertical case. In principle, these fundamental results may be scaled to cryomodule configurations of major accelerator facilities.},
doi = {10.1103/PhysRevAccelBeams.21.064401},
journal = {Physical Review Accelerators and Beams},
number = 6,
volume = 21,
place = {United States},
year = {2018},
month = {6}
}