IPAC2014 - List of Authors (Biancacci, N.)

Paper	Title	Page
TUPRI059	The Proton Synchrotron Transverse impedance model	4096
SUSPSNE060	use link to see paper's listing under its alternate paper code
	S. Persichelli, N. Biancacci, S.S. Gilardoni, M. Migliorati, E. Métral, B. Salvant CERN, Geneva, Switzerland
	The current knowledge of the transverse impedance of the CERN Proton Synchrotron (PS) has been established by theoretical computations, electromagnetic simulations and beam-based measurements at different energies. The transverse coherent tune and phase advance shifts as a function of intensity have been measured in order to evaluate the total effective transverse impedance and its distribution in the accelerator. In order to understand the beam dynamics, the frequency dependence of the impedance budget has also been evaluated considering the individual contribution of several machine devices. 3D models of many PS elements have been realized to perform accurate impedance simulations, while resistive wall and indirect space charge impedances have been evaluated with theoretical and numerical computations. Finally comparisons between the total budget and the measurement results are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI059
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TUPRI062	The Mode Matching Technique Applied to the Transverse Beam Coupling Impedance Calculation of Azimuthally Symmetric Devices of Finite Length	1714
	N. Biancacci, E. Métral, B. Salvant, C. Zannini CERN, Geneva, Switzerland M. Migliorati, L. Palumbo URLS, Rome, Italy V.G. Vaccaro Naples University Federico II and INFN, Napoli, Italy
	The infinite length approximation is often used to simplify the calculation of the beam coupling impedance of accelerator elements. This is expected to be a reasonable assumption for devices whose length is greater than the transverse dimension but may be a less accurate approximation for segmented devices. In this contribution we present the extension of the study of the beam coupling impedance of a finite length device to the transverse plane. In order to take into account the finite length, we decompose the fields in the cavity and in the beam pipe into a set of orthonormal modes and apply the Mode Matching method to obtain the impedance. To validate our method, we will present comparisons between analytical formulas and 3D electromagnetic CST simulations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI062
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TUPRI063	Electromagnetic Simulations for Non-ultrarelativistic Beams and Application to the CERN Low Energy Machines	1718
	C. Zannini, N. Biancacci, T.L. Rijoff, G. Rumolo CERN, Geneva, Switzerland T.L. Rijoff TU Darmstadt, Darmstadt, Germany
	In the framework of the PS-Booster upgrade project an accurate impedance model is needed in order to determine the effect on the beam stability and assess the impact of the new devices to be installed in the machine. CST 3-D EM simulations are widely used to estimate the impedance contribution of the different devices along the CERN accelerator complex. Unlike the highly relativistic case, in which the reliability of the EM solver has been proved in many specific cases by comparing simulations with analytical results, the nonrelativistic case has been so far not yet benchmarked. In order to use systematically CST 3-D EM simulations for the PS-Booster, or even lower energy machines like the antiproton decelerator ELENA, a validation campaign has been carried out. The main complication to single out the beam coupling impedance, as resulting from the interaction of the beam with the surroundings, consisted of removing reliably the strong contribution of the direct space charge of the source bunch, which is included in the EM calculation. The simulation results were then benchmarked with the analytical results for the case of a PEC cylindrical tube and of a ferrite loaded kicker.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI063
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TUPRI071	Transverse Impedance Measurement in RHIC and the AGS	1730
	N. Biancacci CERN, Geneva, Switzerland M. Blaskiewicz, Y. Dutheil, C. Liu, K. Mernick, M.G. Minty, S.M. White BNL, Upton, Long Island, New York, USA
	The RHIC luminosity upgrade program aims for an increase of the polarized proton luminosity by a factor 2. To achieve this goal a significant increase in the beam intensity is foreseen. The beam coupling impedance represents a source of detrimental effects for beam quality and stability at high bunch intensities. In this paper, we evaluate a new global transverse impedance in both RHIC and the AGS with recent measurements of tune shift as a function of bunch intensity. The results are compared to past measurements and present impedance model.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI071
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Paper

Title

Page

TUPRI059

The Proton Synchrotron Transverse impedance model

4096

SUSPSNE060

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

S. Persichelli, N. Biancacci, S.S. Gilardoni, M. Migliorati, E. Métral, B. Salvant
CERN, Geneva, Switzerland

The current knowledge of the transverse impedance of the CERN Proton Synchrotron (PS) has been established by theoretical computations, electromagnetic simulations and beam-based measurements at different energies. The transverse coherent tune and phase advance shifts as a function of intensity have been measured in order to evaluate the total effective transverse impedance and its distribution in the accelerator. In order to understand the beam dynamics, the frequency dependence of the impedance budget has also been evaluated considering the individual contribution of several machine devices. 3D models of many PS elements have been realized to perform accurate impedance simulations, while resistive wall and indirect space charge impedances have been evaluated with theoretical and numerical computations. Finally comparisons between the total budget and the measurement results are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI059

Export •

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

TUPRI062

The Mode Matching Technique Applied to the Transverse Beam Coupling Impedance Calculation of Azimuthally Symmetric Devices of Finite Length

1714

N. Biancacci, E. Métral, B. Salvant, C. Zannini
CERN, Geneva, Switzerland
M. Migliorati, L. Palumbo
URLS, Rome, Italy
V.G. Vaccaro
Naples University Federico II and INFN, Napoli, Italy

The infinite length approximation is often used to simplify the calculation of the beam coupling impedance of accelerator elements. This is expected to be a reasonable assumption for devices whose length is greater than the transverse dimension but may be a less accurate approximation for segmented devices. In this contribution we present the extension of the study of the beam coupling impedance of a finite length device to the transverse plane. In order to take into account the finite length, we decompose the fields in the cavity and in the beam pipe into a set of orthonormal modes and apply the Mode Matching method to obtain the impedance. To validate our method, we will present comparisons between analytical formulas and 3D electromagnetic CST simulations.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI062

Export •

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

TUPRI063

Electromagnetic Simulations for Non-ultrarelativistic Beams and Application to the CERN Low Energy Machines

1718

C. Zannini, N. Biancacci, T.L. Rijoff, G. Rumolo
CERN, Geneva, Switzerland
T.L. Rijoff
TU Darmstadt, Darmstadt, Germany

In the framework of the PS-Booster upgrade project an accurate impedance model is needed in order to determine the effect on the beam stability and assess the impact of the new devices to be installed in the machine. CST 3-D EM simulations are widely used to estimate the impedance contribution of the different devices along the CERN accelerator complex. Unlike the highly relativistic case, in which the reliability of the EM solver has been proved in many specific cases by comparing simulations with analytical results, the nonrelativistic case has been so far not yet benchmarked. In order to use systematically CST 3-D EM simulations for the PS-Booster, or even lower energy machines like the antiproton decelerator ELENA, a validation campaign has been carried out. The main complication to single out the beam coupling impedance, as resulting from the interaction of the beam with the surroundings, consisted of removing reliably the strong contribution of the direct space charge of the source bunch, which is included in the EM calculation. The simulation results were then benchmarked with the analytical results for the case of a PEC cylindrical tube and of a ferrite loaded kicker.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI063

Export •

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

TUPRI071

Transverse Impedance Measurement in RHIC and the AGS

1730

N. Biancacci
CERN, Geneva, Switzerland
M. Blaskiewicz, Y. Dutheil, C. Liu, K. Mernick, M.G. Minty, S.M. White
BNL, Upton, Long Island, New York, USA

The RHIC luminosity upgrade program aims for an increase of the polarized proton luminosity by a factor 2. To achieve this goal a significant increase in the beam intensity is foreseen. The beam coupling impedance represents a source of detrimental effects for beam quality and stability at high bunch intensities. In this paper, we evaluate a new global transverse impedance in both RHIC and the AGS with recent measurements of tune shift as a function of bunch intensity. The results are compared to past measurements and present impedance model.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI071

Export •

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