IPAC2014 - List of Authors (Migliorati, M.)

Paper	Title	Page
TUPRI058	Impedance Studies of the Dummy Septum for CERN PS Multi-turn Extraction	1704
	S. Persichelli, O.E. Berrig, M. Giovannozzi, J. Herbst, J. Kuczerowski, M. Migliorati, B. Salvant CERN, Geneva, Switzerland
	A protection septum has been installed in the CERN PS section 15 in order to mitigate irradiation of the magnetic septum 16 for fast extractions towards the SPS. Impedance studies have been performed, showing that beams circulating in the septum during extraction generate sharp resonances in the coupling impedance. Impedance measurements with the wire technique have been performed, showing a good agreement with simulations. Instability rise times of trapped modes have been evaluated and compared to extraction duration. Solutions for reducing the impact on the stability of the beam have been considered.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI058
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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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TUPRI060	Impedance Studies for the PS Finemet® Loaded Longitudinal Damper	1708
	S. Persichelli, M. Migliorati, M.M. Paoluzzi, B. Salvant CERN, Geneva, Switzerland
	The impedance of the Finemet® loaded longitudinal damper cavity, installed in the CERN Proton Synchrotron straight section 02 during the Long Shutdown 2013-2014, has been evaluated. Time domain simulations with CST Particle Studio have been performed in order to get the longitudinal and transverse impedance of the device and make a comparison with the longitudinal impedance that was measured for a single cell prototype.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI060
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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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THPME017	Electromechanical Analysis of SCDTL Structures	3250
	M. Ciambrella, F. Cardelli, M. Migliorati, A. Mostacci, L. Palumbo URLS, Rome, Italy L. Ficcadenti, V. Pettinacci INFN-Roma, Roma, Italy L. Picardi, C. Ronsivalle ENEA C.R. Frascati, Frascati (Roma), Italy
	The Side Coupled Drift Tube Linac (SCDTL) is a 3 GHz accelerating structure for proton therapy linac designed for TOP-IMPLART, an Intensity Modulated Proton Linear Accelerator for Radio-Therapy. The structure is made up of short DTL accelerating tanks for low current proton beams, coupled by side coupling cavities. The purpose of this paper is to report on the analysis of electromagnetic and the thermo-mechanical behavior for the SCDTL structure. The 3D electromagnetic analysis is used to derive the power dissipation on the structure; then one can infer the temperature distribution and deformation field in order to eventually evaluate their feedback on the electromagnetic properties of the structure as, for instance, the cavity resonant frequency shift. Such a "multi-physics'' analysis has been performed for different supporting stem geometries in order to optimize the shunt impedance and the R/Q for SCDTL cavities.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME017
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Paper

Title

Page

Impedance Studies of the Dummy Septum for CERN PS Multi-turn Extraction

1704

S. Persichelli, O.E. Berrig, M. Giovannozzi, J. Herbst, J. Kuczerowski, M. Migliorati, B. Salvant
CERN, Geneva, Switzerland

A protection septum has been installed in the CERN PS section 15 in order to mitigate irradiation of the magnetic septum 16 for fast extractions towards the SPS. Impedance studies have been performed, showing that beams circulating in the septum during extraction generate sharp resonances in the coupling impedance. Impedance measurements with the wire technique have been performed, showing a good agreement with simulations. Instability rise times of trapped modes have been evaluated and compared to extraction duration. Solutions for reducing the impact on the stability of the beam have been considered.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI058

Export •

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

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)

TUPRI060

Impedance Studies for the PS Finemet® Loaded Longitudinal Damper

1708

S. Persichelli, M. Migliorati, M.M. Paoluzzi, B. Salvant
CERN, Geneva, Switzerland

The impedance of the Finemet® loaded longitudinal damper cavity, installed in the CERN Proton Synchrotron straight section 02 during the Long Shutdown 2013-2014, has been evaluated. Time domain simulations with CST Particle Studio have been performed in order to get the longitudinal and transverse impedance of the device and make a comparison with the longitudinal impedance that was measured for a single cell prototype.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI060

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)

THPME017

Electromechanical Analysis of SCDTL Structures

3250

M. Ciambrella, F. Cardelli, M. Migliorati, A. Mostacci, L. Palumbo
URLS, Rome, Italy
L. Ficcadenti, V. Pettinacci
INFN-Roma, Roma, Italy
L. Picardi, C. Ronsivalle
ENEA C.R. Frascati, Frascati (Roma), Italy

The Side Coupled Drift Tube Linac (SCDTL) is a 3 GHz accelerating structure for proton therapy linac designed for TOP-IMPLART, an Intensity Modulated Proton Linear Accelerator for Radio-Therapy. The structure is made up of short DTL accelerating tanks for low current proton beams, coupled by side coupling cavities. The purpose of this paper is to report on the analysis of electromagnetic and the thermo-mechanical behavior for the SCDTL structure. The 3D electromagnetic analysis is used to derive the power dissipation on the structure; then one can infer the temperature distribution and deformation field in order to eventually evaluate their feedback on the electromagnetic properties of the structure as, for instance, the cavity resonant frequency shift. Such a "multi-physics'' analysis has been performed for different supporting stem geometries in order to optimize the shunt impedance and the R/Q for SCDTL cavities.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME017

Export •

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