IPAC2013 - List of Authors (Randazzo, M.)

Paper	Title	Page
TUPWA061	Observation at CesrTA of the Reduction of the Vertical Beam Size of the Lead Bunch in a Train Due to the Presence of a Precursor Bunch	1841
	M.G. Billing, K.R. Butler, G. Dugan, M.J. Forster, R.E. Meller, G. Ramirez, N.T. Rider, K.G. Sonnad, H.A. Williams CLASSE, Ithaca, New York, USA J.W. Flanagan KEK, Ibaraki, Japan R. Holtzapple, M. Randazzo CalPoly, San Luis Obispo, California, USA M.A. Palmer Fermilab, Batavia, USA
	Funding: Work supported by DOE Award DE-FC02-08ER41538, NSF Award PHY-0734867, PHY-1068662 and the Lepton Collider R&D Coop Agreement: NSF Award PHY-1002467. Electron cloud-induced beam dynamics is being studied at CesrTA under various conditions. These measurements make use of instrumentation for the detection of the coherent self-excited spectrum for each bunch within the train and bunch-by-bunch vertical beam size. In the position spectrum coherent betatron dipole and head-tail motion is detectable for each individual bunch within the train. These techniques are utilized to study the electron cloud-related interactions, which cause the growth of coherent motion and beam size along the train. We report on the observations of the vertical enlargement of the first bunch(es) in 30 bunch-long trains. We also report that the addition of a precursor bunch following the train of bunches and before the start of the next train can counteract the vertical enlargement of the first bunch(es) in the train. Results from these observations will be presented.

TUPWA062	Dependence of Beam Instabilities Caused by Electron Clouds at CesrTA on Variations in Bunch Spacing and Chromaticity	1844
	M.G. Billing, K.R. Butler, G. Dugan, M.J. Forster, R.E. Meller, M.A. Palmer, G. Ramirez, N.T. Rider, K.G. Sonnad, H.A. Williams CLASSE, Ithaca, New York, USA R.F. Campbell, R. Holtzapple, M. Randazzo CalPoly, San Luis Obispo, California, USA J.W. Flanagan KEK, Ibaraki, Japan
	Funding: Work supported by DOE Award DE-FC02-08ER41538, NSF Award PHY-0734867 and the Lepton Collider R&D Coop Agreement: NSF Award PHY-1002467 Experiments have been performed at the Cornell Electron-Positron Storage Ring Test Accelerator (CesrTA) to probe the interaction of the electron cloud with a 2.1 Gev stored positron beam. The purpose of these experiments was to characterize the dependence of beam–electron cloud interactions on the bunch spacing and the vertical chromaticity. These experiments were performed on a 30-bunch positron train, at a fixed current of 0.75mA/bunch. The bunch spacing was varied between 4 and 28 ns at three different vertical chromaticity settings. 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 paper we report on the observations from these experiments and analyze the effects of the electron cloud on the stability of bunches within these different trains.

Paper

Title

Page

Observation at CesrTA of the Reduction of the Vertical Beam Size of the Lead Bunch in a Train Due to the Presence of a Precursor Bunch

1841

M.G. Billing, K.R. Butler, G. Dugan, M.J. Forster, R.E. Meller, G. Ramirez, N.T. Rider, K.G. Sonnad, H.A. Williams
CLASSE, Ithaca, New York, USA
J.W. Flanagan
KEK, Ibaraki, Japan
R. Holtzapple, M. Randazzo
CalPoly, San Luis Obispo, California, USA
M.A. Palmer
Fermilab, Batavia, USA

Funding: Work supported by DOE Award DE-FC02-08ER41538, NSF Award PHY-0734867, PHY-1068662 and the Lepton Collider R&D Coop Agreement: NSF Award PHY-1002467.
Electron cloud-induced beam dynamics is being studied at CesrTA under various conditions. These measurements make use of instrumentation for the detection of the coherent self-excited spectrum for each bunch within the train and bunch-by-bunch vertical beam size. In the position spectrum coherent betatron dipole and head-tail motion is detectable for each individual bunch within the train. These techniques are utilized to study the electron cloud-related interactions, which cause the growth of coherent motion and beam size along the train. We report on the observations of the vertical enlargement of the first bunch(es) in 30 bunch-long trains. We also report that the addition of a precursor bunch following the train of bunches and before the start of the next train can counteract the vertical enlargement of the first bunch(es) in the train. Results from these observations will be presented.

TUPWA062

Dependence of Beam Instabilities Caused by Electron Clouds at CesrTA on Variations in Bunch Spacing and Chromaticity

1844

M.G. Billing, K.R. Butler, G. Dugan, M.J. Forster, R.E. Meller, M.A. Palmer, G. Ramirez, N.T. Rider, K.G. Sonnad, H.A. Williams
CLASSE, Ithaca, New York, USA
R.F. Campbell, R. Holtzapple, M. Randazzo
CalPoly, San Luis Obispo, California, USA
J.W. Flanagan
KEK, Ibaraki, Japan

Funding: Work supported by DOE Award DE-FC02-08ER41538, NSF Award PHY-0734867 and the Lepton Collider R&D Coop Agreement: NSF Award PHY-1002467
Experiments have been performed at the Cornell Electron-Positron Storage Ring Test Accelerator (CesrTA) to probe the interaction of the electron cloud with a 2.1 Gev stored positron beam. The purpose of these experiments was to characterize the dependence of beam–electron cloud interactions on the bunch spacing and the vertical chromaticity. These experiments were performed on a 30-bunch positron train, at a fixed current of 0.75mA/bunch. The bunch spacing was varied between 4 and 28 ns at three different vertical chromaticity settings. 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 paper we report on the observations from these experiments and analyze the effects of the electron cloud on the stability of bunches within these different trains.