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Title: Observations of Short-Range Wadefield Effects in Tesla-Type Superconducting RF Cavities

Abstract

The Fermilab Accelerator Science and Technology (FAST) facility has a unique configuration of a photocathode rf gun beam injecting two TESLA-type single cavities (CC1 and CC2) in series prior to the cryomodule. To investigate short-range wakefield effects, we have steered the beam to minimize the signals in the higher-order mode (HOM) detectors of CC1 and CC2 for a baseline, and then used a vertical corrector between the two cavities to steer the beam off axis at an angle into CC2. A Hamamatsu synchroscan streak camera viewing a downstream OTR screen provided an image of y-t effects within the micropulses with ~10-micron spatial resolution and 2-ps temporal resolution. At 500 pC/b, 50 b, and 4 mrad off-axis steering into CC2, we observed an ~ 100-micron head-tail centroid shift in the streak camera image y(t)-profiles. This centroid shift value is 5 times larger than the observed HOM-driven centroid oscillation within the macropulse and is consistent with a calculat ed short-range wakefield effect. Additional results for kick-angle compensations will be presented.

Authors:
 [1];  [2];  [2];  [2]
  1. Los Alamos
  2. Fermilab
Publication Date:
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)
OSTI Identifier:
1571788
Report Number(s):
FERMILAB-POSTER-19-110-AD
oai:inspirehep.net:1761040
DOE Contract Number:  
AC02-07CH11359
Resource Type:
Conference
Resource Relation:
Conference: 39th International Free Electron Laser Conference, Hamburg, Germany, 08/26-08/30/2019
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS

Citation Formats

Lumpkin, A. H., Thurman-Keup, R., Edstrom, D., and Ruan, J. Observations of Short-Range Wadefield Effects in Tesla-Type Superconducting RF Cavities. United States: N. p., 2019. Web.
Lumpkin, A. H., Thurman-Keup, R., Edstrom, D., & Ruan, J. Observations of Short-Range Wadefield Effects in Tesla-Type Superconducting RF Cavities. United States.
Lumpkin, A. H., Thurman-Keup, R., Edstrom, D., and Ruan, J. Thu . "Observations of Short-Range Wadefield Effects in Tesla-Type Superconducting RF Cavities". United States. https://www.osti.gov/servlets/purl/1571788.
@article{osti_1571788,
title = {Observations of Short-Range Wadefield Effects in Tesla-Type Superconducting RF Cavities},
author = {Lumpkin, A. H. and Thurman-Keup, R. and Edstrom, D. and Ruan, J.},
abstractNote = {The Fermilab Accelerator Science and Technology (FAST) facility has a unique configuration of a photocathode rf gun beam injecting two TESLA-type single cavities (CC1 and CC2) in series prior to the cryomodule. To investigate short-range wakefield effects, we have steered the beam to minimize the signals in the higher-order mode (HOM) detectors of CC1 and CC2 for a baseline, and then used a vertical corrector between the two cavities to steer the beam off axis at an angle into CC2. A Hamamatsu synchroscan streak camera viewing a downstream OTR screen provided an image of y-t effects within the micropulses with ~10-micron spatial resolution and 2-ps temporal resolution. At 500 pC/b, 50 b, and 4 mrad off-axis steering into CC2, we observed an ~ 100-micron head-tail centroid shift in the streak camera image y(t)-profiles. This centroid shift value is 5 times larger than the observed HOM-driven centroid oscillation within the macropulse and is consistent with a calculat ed short-range wakefield effect. Additional results for kick-angle compensations will be presented.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2019},
month = {8}
}

Conference:
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