NAPAC2016 - List of Authors (Antipov, S. A.)

Paper	Title	Page
THPOA48	Model of Electron Cloud Instability in Fermilab Recycler	1197
	S. A. Antipov University of Chicago, Chicago, Illinois, USA A.V. Burov, S. Nagaitsev Fermilab, Batavia, Illinois, USA
	An electron cloud instability might limit the intensity in the Fermilab Recycler after the PIP-II upgrade. A multibunch instability typically develops in the horizontal plane within a hundred turns and, in certain conditions, leads to beam loss. Recent studies have indicated that the instability is caused by an electron cloud, trapped in the Recycler index dipole magnets. We developed an analytical model of an electron cloud driven instability with the electrons trapped in combined function dipoles. The resulting instability growth rate of about 30 revolutions is consistent with experimental observations and qualitatively agrees with the simulation in the PEI code. The model allows an estimation of the instability rate for the future in-tensity upgrades.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-THPOA48
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THPOA49	Electron Cloud Trapping in Recycler Combined Function Dipole Magnets	1200
SUPO06	use link to see paper's listing under its alternate paper code
	S. A. Antipov University of Chicago, Chicago, Illinois, USA S. Nagaitsev Fermilab, Batavia, Illinois, USA
	Electron cloud can lead to a fast instability in intense proton and positron beams in circular accelerators. In the Fermilab Recycler the electron cloud is confined within its combined function magnets. We show that combined function magnets trap the electron cloud with their magnetic field, present the results of analytical estimates of trapping, and compare them to numerical simulations of electron cloud formation. The electron cloud in a combined function magnet is located at the beam center and up to 1% of the particles can be trapped by its magnetic field. Since the process of electron cloud build-up is exponential, once trapped this amount of electrons significantly increases the density of the cloud on the next revolution. In a Recycler combined function dipole this multi-turn accumulations allows the electron cloud reaching final intensities orders of magnitude greater than in a pure dipole. The multi-turn build-up can be stopped by injection of a single clearing bunch of 1*10¹⁰ p at any position in the ring.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-THPOA49
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Model of Electron Cloud Instability in Fermilab Recycler

1197

S. A. Antipov
University of Chicago, Chicago, Illinois, USA
A.V. Burov, S. Nagaitsev
Fermilab, Batavia, Illinois, USA

An electron cloud instability might limit the intensity in the Fermilab Recycler after the PIP-II upgrade. A multibunch instability typically develops in the horizontal plane within a hundred turns and, in certain conditions, leads to beam loss. Recent studies have indicated that the instability is caused by an electron cloud, trapped in the Recycler index dipole magnets. We developed an analytical model of an electron cloud driven instability with the electrons trapped in combined function dipoles. The resulting instability growth rate of about 30 revolutions is consistent with experimental observations and qualitatively agrees with the simulation in the PEI code. The model allows an estimation of the instability rate for the future in-tensity upgrades.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-THPOA48

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOA49

Electron Cloud Trapping in Recycler Combined Function Dipole Magnets

1200

SUPO06

use link to see paper's listing under its alternate paper code

S. A. Antipov
University of Chicago, Chicago, Illinois, USA
S. Nagaitsev
Fermilab, Batavia, Illinois, USA

Electron cloud can lead to a fast instability in intense proton and positron beams in circular accelerators. In the Fermilab Recycler the electron cloud is confined within its combined function magnets. We show that combined function magnets trap the electron cloud with their magnetic field, present the results of analytical estimates of trapping, and compare them to numerical simulations of electron cloud formation. The electron cloud in a combined function magnet is located at the beam center and up to 1% of the particles can be trapped by its magnetic field. Since the process of electron cloud build-up is exponential, once trapped this amount of electrons significantly increases the density of the cloud on the next revolution. In a Recycler combined function dipole this multi-turn accumulations allows the electron cloud reaching final intensities orders of magnitude greater than in a pure dipole. The multi-turn build-up can be stopped by injection of a single clearing bunch of 1*10¹⁰ p at any position in the ring.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2016-THPOA49

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)