IPAC2015 - List of Authors (Migliorati, M.)

Paper	Title	Page
MOPJE072	Simulations and Measurements of Longitudinal Coupled-bunch Instabilities in the CERN PS	479
	L. Ventura, H. Damerau, M. Migliorati, G. Sterbini CERN, Geneva, Switzerland M. Migliorati, L. Ventura INFN-Roma1, Rome, Italy M. Migliorati University of Rome La Sapienza, Rome, Italy L. Ventura University of Rome "La Sapienza", Rome, Italy
	Among various and challenging objectives of the LHC Injectors Upgrade project (LIU), one aim is to double the beam intensity of the CERN Proton Synchrotron (PS) in order to achieve the integrated luminosity target of the High-Luminosity LHC project (HL-LHC). A known limitation to reach the required high intensity is caused by the longitudinal coupled-bunch oscillations developing above the transition energy. The unwanted oscillations induce large bunch-to-bunch intensity variations not compatible with the specifications of the future LHC-type beams. A wide-band longitudinal damper has been installed in the PS to suppress these instabilities and is going to be commissioned. A measurement campaign of coupled-bunch oscillations has been launched to substantiate the extrapolations and predictions for the future High Luminosity LHC beam with the final aim to determine the maximum intensity that could be provided to the LHC. In parallel a Simulink© model of the PS is going to be implemented to predict the machine behavior in the parameter space of LIU and to be used during the beam commissioning and optimization of the feedback system.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPJE072
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TUPWA025	Beam Heat Load Analysis with COLDDIAG: A Cold Vacuum Chamber for Diagnostics	1459
	R. Voutta, S. Casalbuoni, S. Gerstl, A.W. Grau, T. Holubek, D. Saez de Jauregui KIT, Eggenstein-Leopoldshafen, Germany R. Bartolini, M.P. Cox, E.C. Longhi, G. Rehm, J.C. Schouten, R.P. Walker DLS, Oxfordshire, United Kingdom M. Migliorati, B. Spataro INFN/LNF, Frascati (Roma), Italy
	The knowledge of the heat intake from the electron beam is essential to design the cryogenic layout of superconducting insertion devices. With the aim of measuring the beam heat load to a cold bore and understanding the responsible mechanisms, a cold vacuum chamber for diagnostics (COLDDIAG) has been built. The instrumentation comprises temperature sensors, pressure gauges, mass spectrometers and retarding field analyzers, which allow to study the beam heat load and the influence of the cryosorbed gas layer. COLDDIAG was installed in the storage ring of the Diamond Light Source from September 2012 to August 2013. During this time measurements were performed for a wide range of machine conditions, employing the various measuring capabilities of the device. Here we report on the analysis of the measured beam heat load, pressure and gas content, as well as the low energy charged particle flux and spectrum as a function of the electron beam parameters.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWA025
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MOPJE047	Chromaticity Dependence of the Transverse Effective Impedance in the CERN Proton Synchrotron	395
	S. Persichelli, N. Biancacci, S.S. Gilardoni, A. Huschauer, E. Métral, B. Salvant, R. Wasef CERN, Geneva, Switzerland M. Migliorati University of Rome La Sapienza, Rome, Italy
	The current knowledge of the transverse impedance of the Proton Synchrotron (PS) has been established with beam-based measurements at different energies. The transverse coherent tune shift as a function of the beam intensity has been measured in order to evaluate the total effective imaginary part of the transverse impedance and its localization in the accelerator at the energies of 2, 7, 13 and 25 GeV. Measurements have been performed changing the chromaticity for every tune shift scan with intensity. The data analysis revealed an increase of impedance with chromaticity for all the energies considered. That transverse impedance can be compared with the previously evaluated theoretical impedance budget taking into account the individual contribution of several machine devices. The missing impedance is finally highlighted.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPJE047
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Paper

Title

Page

Simulations and Measurements of Longitudinal Coupled-bunch Instabilities in the CERN PS

479

L. Ventura, H. Damerau, M. Migliorati, G. Sterbini
CERN, Geneva, Switzerland
M. Migliorati, L. Ventura
INFN-Roma1, Rome, Italy
M. Migliorati
University of Rome La Sapienza, Rome, Italy
L. Ventura
University of Rome "La Sapienza", Rome, Italy

Among various and challenging objectives of the LHC Injectors Upgrade project (LIU), one aim is to double the beam intensity of the CERN Proton Synchrotron (PS) in order to achieve the integrated luminosity target of the High-Luminosity LHC project (HL-LHC). A known limitation to reach the required high intensity is caused by the longitudinal coupled-bunch oscillations developing above the transition energy. The unwanted oscillations induce large bunch-to-bunch intensity variations not compatible with the specifications of the future LHC-type beams. A wide-band longitudinal damper has been installed in the PS to suppress these instabilities and is going to be commissioned. A measurement campaign of coupled-bunch oscillations has been launched to substantiate the extrapolations and predictions for the future High Luminosity LHC beam with the final aim to determine the maximum intensity that could be provided to the LHC. In parallel a Simulink© model of the PS is going to be implemented to predict the machine behavior in the parameter space of LIU and to be used during the beam commissioning and optimization of the feedback system.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPJE072

Export •

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

TUPWA025

Beam Heat Load Analysis with COLDDIAG: A Cold Vacuum Chamber for Diagnostics

1459

R. Voutta, S. Casalbuoni, S. Gerstl, A.W. Grau, T. Holubek, D. Saez de Jauregui
KIT, Eggenstein-Leopoldshafen, Germany
R. Bartolini, M.P. Cox, E.C. Longhi, G. Rehm, J.C. Schouten, R.P. Walker
DLS, Oxfordshire, United Kingdom
M. Migliorati, B. Spataro
INFN/LNF, Frascati (Roma), Italy

The knowledge of the heat intake from the electron beam is essential to design the cryogenic layout of superconducting insertion devices. With the aim of measuring the beam heat load to a cold bore and understanding the responsible mechanisms, a cold vacuum chamber for diagnostics (COLDDIAG) has been built. The instrumentation comprises temperature sensors, pressure gauges, mass spectrometers and retarding field analyzers, which allow to study the beam heat load and the influence of the cryosorbed gas layer. COLDDIAG was installed in the storage ring of the Diamond Light Source from September 2012 to August 2013. During this time measurements were performed for a wide range of machine conditions, employing the various measuring capabilities of the device. Here we report on the analysis of the measured beam heat load, pressure and gas content, as well as the low energy charged particle flux and spectrum as a function of the electron beam parameters.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWA025

Export •

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

MOPJE047

Chromaticity Dependence of the Transverse Effective Impedance in the CERN Proton Synchrotron

395

S. Persichelli, N. Biancacci, S.S. Gilardoni, A. Huschauer, E. Métral, B. Salvant, R. Wasef
CERN, Geneva, Switzerland
M. Migliorati
University of Rome La Sapienza, Rome, Italy

The current knowledge of the transverse impedance of the Proton Synchrotron (PS) has been established with beam-based measurements at different energies. The transverse coherent tune shift as a function of the beam intensity has been measured in order to evaluate the total effective imaginary part of the transverse impedance and its localization in the accelerator at the energies of 2, 7, 13 and 25 GeV. Measurements have been performed changing the chromaticity for every tune shift scan with intensity. The data analysis revealed an increase of impedance with chromaticity for all the energies considered. That transverse impedance can be compared with the previously evaluated theoretical impedance budget taking into account the individual contribution of several machine devices. The missing impedance is finally highlighted.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPJE047

Export •

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