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Title: Observation of electron cloud instabilities and emittance dilution at the Cornell electron-positron Storage ring Test Accelerator

Electron cloud related emittance dilution and instabilities of bunch trains limit the performance of high intensity circular colliders. One of the key goals of the Cornell electron-positron storage ring Test Accelerator (CesrTA) research program is to improve our understanding of how the electron cloud alters the dynamics of bunches within the train. Single bunch beam diagnostics have been developed to measure the beam spectra, vertical beam size, two important dynamical effects of beams interacting with the electron cloud, for bunch trains on a turn-by-turn basis. Experiments have been performed at CesrTA to probe the interaction of the electron cloud with stored positron bunch trains. The purpose of these experiments was to characterize the dependence of beam-electron cloud interactions on the machine parameters such as bunch spacing, vertical chromaticity, and bunch current. The beam dynamics of the stored beam, in the presence of the electron cloud, was quantified using: 1) a gated beam position monitor (BPM) and spectrum analyzer to measure the bunch-by-bunch frequency spectrum of the bunch trains, 2) an x-ray beam size monitor to record the bunch-by-bunch, turn-by-turn vertical size of each bunch within the trains. In this study we report on the observations from these experiments and analyzemore » the effects of the electron cloud on the stability of bunches in a train under many different operational conditions.« less
Authors:
 [1] ;  [2] ;  [1] ;  [2] ;  [3] ;  [1] ;  [1] ;  [4] ;  [2] ;  [5] ;  [1] ;  [1] ;  [2]
  1. California Polytechnic State Univ. (CalPoly), San Luis Obispo, CA (United States)
  2. Cornell Univ., Ithaca, NY (United States)
  3. High Energy Accelerator Research Organization (KEK), Ibaraki (Japan)
  4. Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
  5. Cornell Univ., Ithaca, NY (United States); High Energy Accelerator Research Organization (KEK), Ibaraki (Japan)
Publication Date:
Report Number(s):
FERMILAB-PUB-16-409-APC
Journal ID: ISSN 1748-0221; 1449141
Grant/Contract Number:
AC02-07CH11359
Type:
Accepted Manuscript
Journal Name:
Journal of Instrumentation
Additional Journal Information:
Journal Volume: 11; Journal Issue: 04; Journal ID: ISSN 1748-0221
Publisher:
Institute of Physics (IOP)
Research Org:
Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; beam dynamics; coherent instabilities
OSTI Identifier:
1329068