IPAC2014 - List of Authors (Giovannozzi, M.)

Paper	Title	Page
TUPRO002	Fringe Fields Modeling for the High Luminosity LHC Large Aperture Quadrupoles	993
	B. Dalena, A. Chancé, O. Gabouev CEA/IRFU, Gif-sur-Yvette, France R. Appleby, D.R. Brett UMAN, Manchester, United Kingdom R. De Maria, M. Giovannozzi CERN, Geneva, Switzerland J. Payet CEA/DSM/IRFU, France
	Funding: The research leading to these results has received funding from the European Commission under the FP7 project HiLumi LHC, GA no. 284404, co-funded by the DoE, USA and KEK, Japan. The HL-LHC Upgrade project relies on large aperture magnets (mainly the inner Triplet and the separation dipole D1). The beam is much more sensitive to non-linear perturbations in this region, such as those induced by the fringe fields of the low-beta quadrupoles. Analytical evaluations of detuning with amplitude and chromatic effects show that the effect is small, but not negligible. Therefore, the effect on long-term beam dynamics is evaluated via tracking simulations. Different tracking models are compared in order to provide a numerical estimate of this effect due to the proposed inner triplet quadrupoles. The implementation of the fringe fields in SixTrack, to be used for dynamic apertures studies, is also discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO002
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TUPRO008	Specification of Field Quality of the Interaction Region Magnets of the High Luminosity LHC Based on Dynamic Aperture	1013
	Y. Nosochkov, Y. Cai, M.-H. Wang SLAC, Menlo Park, California, USA R. De Maria, S.D. Fartoukh, M. Giovannozzi, E. McIntosh CERN, Geneva, Switzerland
	Funding: Work partly funded by the European Commission within the Framework Programme 7 Capacities Specific Programme, Grant Agreement 284404, and by the US LARP through US Department of Energy. The high luminosity LHC upgrade (HL-LHC) requires new magnets in the low-beta interaction regions with a larger aperture than in the existing LHC. These include the Nb3Sn superconducting (SC) inner triplet quadrupoles, Nb-Ti SC separation dipoles D1 and D2, and SC matching quadrupoles Q4 and Q5. The large aperture is necessary for accommodating the increased beam size caused by significantly higher beta functions in these magnets in the collision optics. The high beta functions also enhance the effects of field errors in these magnets leading to a smaller dynamic aperture (DA). It is, therefore, critical to determine the field quality specifications for these magnets which 1) satisfy an acceptable DA, and 2) are realistically achievable. The estimates of expected field quality obtained from magnetic field calculations and measurements were used as a starting point. Then, based on the DA study, the field errors were optimized in order to reach an acceptable DA. The DA calculations were performed using SixTrack. Details of the optimization process and summary of the field quality specifications for collision and injection energies are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO008
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TUPRO009	Simple Models Describing the Time-evolution of Luminosity in Hadron Colliders	1017
	M. Giovannozzi CERN, Geneva, Switzerland
	In recent years, several studies have been performed to describe the evolution of the losses in circular proton machines. Considerations based on single-particle, non-linear beam dynamics allowed building models that, albeit simple, proved to be in good agreement with measurements. These initial results have been generalised, thus opening the possibility to describe the luminosity evolution in a circular hadron collider. In this paper, the focus is on the derivation of scaling laws for the integrated luminosity, taking into account both burn off and additional pseudo-diffusive effects. The proposed models are applied to the analysis of the data collected during the LHC Run I and the outcome is discussed in detail.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO009
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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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WEPRI094	Conceptual Design Study of the High Luminosity LHC Recombination Dipole	2712
	G.L. Sabbi, X. Wang LBNL, Berkeley, California, USA G. Arduini, M. Giovannozzi, E. Todesco CERN, Geneva, Switzerland
	Funding: Work supported by the U.S. DOE LHC Accelerator Research Program. The HiLumi LHC Design Study is partly funded by the European Commission within the Framework Programme 7. The interaction region design of the High-Luminosity LHC requires replacing the recombination dipole magnets (D2) with new ones. The preliminary specifications include an aperture of 10⁵ mm, with 186 mm separation between the twin-aperture axes, and an operating field in the range of 3.5 to 4.5 T. The main design challenge is to decouple the magnetic field in the two apertures and ensure good field quality. In this paper, we present a new approach to address these issues, and provide expected harmonics for geometric, saturation and persistent current effects. The feasibility of an operating field at the high end of the range considered is also discussed, to minimize the D2 magnet length and facilitate the space allocation for other components.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI094
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THPRO079	Quantitative Analysis of Trapping Probability for Quasi-integrable Two-degree of Freedom Maps	3065
	M. Giovannozzi, C. Hernalsteens, J. Williams CERN, Geneva, Switzerland A. Bazzani Bologna University, Bologna, Italy C. Hernalsteens EPFL, Lausanne, Switzerland
	A key ingredient for the Multi-Turn Extraction (MTE) at the CERN Proton Synchrotron is the beam trapping in stable islands of transverse phase space. In a previous paper a method allowing analytical estimation of the fraction of beam trapped into resonance islands as a function of the Hamiltonian parameters has been presented. Such a method applies to one-degree of freedom models of betatronic motion. In this paper, the analysis is extended to the more realistic and challenging case of two-degree of freedom systems, in which the interplay between the horizontal and vertical motion is fully included. Numerical simulations are presented and the results are discussed in detail.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO079
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THPRO080	The FiDeL Model at 7 TeV	3069
	N. Aquilina, M. Giovannozzi, P. Hagen, M. Lamont, A. Langner, E. Todesco, R. Tomás, J. Wenninger CERN, Geneva, Switzerland N.J. Sammut University of Malta, Information and Communication Technology, Msida, Malta
	After the long shut down of 2013-2014, the LHC energy will be pushed toward 7 TeV. In this range of energy, the main magnets will enter a new regime. For this reason, this paper will present a detailed study of the performance of the FiDeL model that could be critical for the operation in 2015. In particular this paper will study the saturation component and its precision in the model, together with the hysteresis error. The effect of these two components and their errors on the beta-beating is also given. Furthermore, an estimate of the dynamic effects visible in the tune and chromaticity will be presented for the 7 TeV operation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO080
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THPME175	A Beam Gas Vertex Detector for Beam Size Measurement in the LHC	3680
	P. Hopchev, V. Baglin, C. Barschel, E. Bravin, G. Bregliozzi, N. Chritin, B. Dehning, M. Ferro-Luzzi, C. Gaspar, M. Giovannozzi, R. Jacobsson, L.K. Jensen, O.R. Jones, N.J. Jurado, V. Kain, M. Kuhn, B. Luthi, P. Magagnin, R. Matev, N. Neufeld, J. Panman, M.N. Rihl, V. Salustino Guimaraes, B. Salvant, R. Veness, E. van Herwijnen CERN, Geneva, Switzerland A. Bay, F. Blanc, S. Gianì, G.J. Haefeli, T. Nakada, B. Rakotomiaramanana, O. Schneider, M. Tobin, Q.D. Veyrat, Z. Xu EPFL, Lausanne, Switzerland R. Greim, W. Karpinski, T. Kirn, S. Schael, G. Schwering, M. Wlochal, A. von Dratzig RWTH, Aachen, Germany R. Matev Sofia University St. Kliment Ohridski, Faculty of Physics, Sofia, Bulgaria
	The Beam Gas Vertex (BGV) detector is foreseen as a possible non-invasive beam size measurement instrument for the LHC and its luminosity upgrade. This technique is based on the reconstruction of beam gas interaction vertices, where the charged particles produced in inelastic beam gas interactions are measured with high-precision tracking detectors. The design studies and expected performance of the currently developed BGV prototype will be presented with an overview given of the associated vacuum, detector, and readout systems. A brief description will be given of the BGV Monte Carlo simulation application, which is based on the LHCb computing framework (Gaudi) and allows simulation studies to be performed and online event reconstruction algorithms to be developed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME175
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Fringe Fields Modeling for the High Luminosity LHC Large Aperture Quadrupoles

993

B. Dalena, A. Chancé, O. Gabouev
CEA/IRFU, Gif-sur-Yvette, France
R. Appleby, D.R. Brett
UMAN, Manchester, United Kingdom
R. De Maria, M. Giovannozzi
CERN, Geneva, Switzerland
J. Payet
CEA/DSM/IRFU, France

Funding: The research leading to these results has received funding from the European Commission under the FP7 project HiLumi LHC, GA no. 284404, co-funded by the DoE, USA and KEK, Japan.
The HL-LHC Upgrade project relies on large aperture magnets (mainly the inner Triplet and the separation dipole D1). The beam is much more sensitive to non-linear perturbations in this region, such as those induced by the fringe fields of the low-beta quadrupoles. Analytical evaluations of detuning with amplitude and chromatic effects show that the effect is small, but not negligible. Therefore, the effect on long-term beam dynamics is evaluated via tracking simulations. Different tracking models are compared in order to provide a numerical estimate of this effect due to the proposed inner triplet quadrupoles. The implementation of the fringe fields in SixTrack, to be used for dynamic apertures studies, is also discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO002

Export •

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

TUPRO008

Specification of Field Quality of the Interaction Region Magnets of the High Luminosity LHC Based on Dynamic Aperture

1013

Y. Nosochkov, Y. Cai, M.-H. Wang
SLAC, Menlo Park, California, USA
R. De Maria, S.D. Fartoukh, M. Giovannozzi, E. McIntosh
CERN, Geneva, Switzerland

Funding: Work partly funded by the European Commission within the Framework Programme 7 Capacities Specific Programme, Grant Agreement 284404, and by the US LARP through US Department of Energy.
The high luminosity LHC upgrade (HL-LHC) requires new magnets in the low-beta interaction regions with a larger aperture than in the existing LHC. These include the Nb3Sn superconducting (SC) inner triplet quadrupoles, Nb-Ti SC separation dipoles D1 and D2, and SC matching quadrupoles Q4 and Q5. The large aperture is necessary for accommodating the increased beam size caused by significantly higher beta functions in these magnets in the collision optics. The high beta functions also enhance the effects of field errors in these magnets leading to a smaller dynamic aperture (DA). It is, therefore, critical to determine the field quality specifications for these magnets which 1) satisfy an acceptable DA, and 2) are realistically achievable. The estimates of expected field quality obtained from magnetic field calculations and measurements were used as a starting point. Then, based on the DA study, the field errors were optimized in order to reach an acceptable DA. The DA calculations were performed using SixTrack. Details of the optimization process and summary of the field quality specifications for collision and injection energies are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO008

Export •

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

TUPRO009

Simple Models Describing the Time-evolution of Luminosity in Hadron Colliders

1017

M. Giovannozzi
CERN, Geneva, Switzerland

In recent years, several studies have been performed to describe the evolution of the losses in circular proton machines. Considerations based on single-particle, non-linear beam dynamics allowed building models that, albeit simple, proved to be in good agreement with measurements. These initial results have been generalised, thus opening the possibility to describe the luminosity evolution in a circular hadron collider. In this paper, the focus is on the derivation of scaling laws for the integrated luminosity, taking into account both burn off and additional pseudo-diffusive effects. The proposed models are applied to the analysis of the data collected during the LHC Run I and the outcome is discussed in detail.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO009

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

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

Export •

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

WEPRI094

Conceptual Design Study of the High Luminosity LHC Recombination Dipole

2712

G.L. Sabbi, X. Wang
LBNL, Berkeley, California, USA
G. Arduini, M. Giovannozzi, E. Todesco
CERN, Geneva, Switzerland

Funding: Work supported by the U.S. DOE LHC Accelerator Research Program. The HiLumi LHC Design Study is partly funded by the European Commission within the Framework Programme 7.
The interaction region design of the High-Luminosity LHC requires replacing the recombination dipole magnets (D2) with new ones. The preliminary specifications include an aperture of 10⁵ mm, with 186 mm separation between the twin-aperture axes, and an operating field in the range of 3.5 to 4.5 T. The main design challenge is to decouple the magnetic field in the two apertures and ensure good field quality. In this paper, we present a new approach to address these issues, and provide expected harmonics for geometric, saturation and persistent current effects. The feasibility of an operating field at the high end of the range considered is also discussed, to minimize the D2 magnet length and facilitate the space allocation for other components.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRI094

Export •

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

THPRO079

Quantitative Analysis of Trapping Probability for Quasi-integrable Two-degree of Freedom Maps

3065

M. Giovannozzi, C. Hernalsteens, J. Williams
CERN, Geneva, Switzerland
A. Bazzani
Bologna University, Bologna, Italy
C. Hernalsteens
EPFL, Lausanne, Switzerland

A key ingredient for the Multi-Turn Extraction (MTE) at the CERN Proton Synchrotron is the beam trapping in stable islands of transverse phase space. In a previous paper a method allowing analytical estimation of the fraction of beam trapped into resonance islands as a function of the Hamiltonian parameters has been presented. Such a method applies to one-degree of freedom models of betatronic motion. In this paper, the analysis is extended to the more realistic and challenging case of two-degree of freedom systems, in which the interplay between the horizontal and vertical motion is fully included. Numerical simulations are presented and the results are discussed in detail.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO079

Export •

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

THPRO080

The FiDeL Model at 7 TeV

3069

N. Aquilina, M. Giovannozzi, P. Hagen, M. Lamont, A. Langner, E. Todesco, R. Tomás, J. Wenninger
CERN, Geneva, Switzerland
N.J. Sammut
University of Malta, Information and Communication Technology, Msida, Malta

After the long shut down of 2013-2014, the LHC energy will be pushed toward 7 TeV. In this range of energy, the main magnets will enter a new regime. For this reason, this paper will present a detailed study of the performance of the FiDeL model that could be critical for the operation in 2015. In particular this paper will study the saturation component and its precision in the model, together with the hysteresis error. The effect of these two components and their errors on the beta-beating is also given. Furthermore, an estimate of the dynamic effects visible in the tune and chromaticity will be presented for the 7 TeV operation.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO080

Export •

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

THPME175

A Beam Gas Vertex Detector for Beam Size Measurement in the LHC

3680

P. Hopchev, V. Baglin, C. Barschel, E. Bravin, G. Bregliozzi, N. Chritin, B. Dehning, M. Ferro-Luzzi, C. Gaspar, M. Giovannozzi, R. Jacobsson, L.K. Jensen, O.R. Jones, N.J. Jurado, V. Kain, M. Kuhn, B. Luthi, P. Magagnin, R. Matev, N. Neufeld, J. Panman, M.N. Rihl, V. Salustino Guimaraes, B. Salvant, R. Veness, E. van Herwijnen
CERN, Geneva, Switzerland
A. Bay, F. Blanc, S. Gianì, G.J. Haefeli, T. Nakada, B. Rakotomiaramanana, O. Schneider, M. Tobin, Q.D. Veyrat, Z. Xu
EPFL, Lausanne, Switzerland
R. Greim, W. Karpinski, T. Kirn, S. Schael, G. Schwering, M. Wlochal, A. von Dratzig
RWTH, Aachen, Germany
R. Matev
Sofia University St. Kliment Ohridski, Faculty of Physics, Sofia, Bulgaria

The Beam Gas Vertex (BGV) detector is foreseen as a possible non-invasive beam size measurement instrument for the LHC and its luminosity upgrade. This technique is based on the reconstruction of beam gas interaction vertices, where the charged particles produced in inelastic beam gas interactions are measured with high-precision tracking detectors. The design studies and expected performance of the currently developed BGV prototype will be presented with an overview given of the associated vacuum, detector, and readout systems. A brief description will be given of the BGV Monte Carlo simulation application, which is based on the LHCb computing framework (Gaudi) and allows simulation studies to be performed and online event reconstruction algorithms to be developed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME175

Export •

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