IPAC2015 - List of Authors (Papaphilippou, Y.)

Paper	Title	Page
MOPWA050	Beam Dynamics Studies to Develop a High-energy Luminosity Model for the LHC	233
	G. Campogiani Rome University La Sapienza, Roma, Italy Y. Papaphilippou CERN, Geneva, Switzerland
	Funding: support provided by the EPS-AG through the EPS-AG student grant program Luminosity, the key figure of merit of a collider as the LHC, depends on the brightness of the colliding beams. This makes the intensity dependent beam-beam effect the dominant performance limiting factor at collision. The parasitic interactions due to the electromagnetic mutual influence of the beams in the interaction region of a collider induce a diffusive behaviour in the tails of the beam. The evolution of charge density distribution is studied to model the beam tails evolution in order to characterize beam lifetime and luminosity. To achieve this, tools are developed for tracking distributions of arbitrary number of single particles interacting with the opposing strong-beam, to analyse the halo formation processes due to the combined effect of beam-beam and machine non-linearities. This paper presents preliminary results of the simulations, both for the LHC Run I and nominal LHC parameters. The former will be used to benchmark simulations while the latter aims at supporting luminosity estimate for the Run II.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPWA050
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MOPJE034	Low Emittance Tuning for the CLIC Damping Rings	356
	J. Alabau-Gonzalvo, F. Antoniou, Y. Papaphilippou CERN, Geneva, Switzerland
	A study on the sensitivity of the CLIC Damping Ring lattice to different sources of misalignment is presented. Dipole and quadrupole rolls, quadrupole and sextupole vertical offsets are considered, as well as the impact of a finite BPM resolution. The result of this study defines a low emittance tuning procedure and establishes alignment tolerances to preserve the vertical emittance below the design value (1 pm·rad). Non-linear dynamics studies including dynamic aperture and frequency maps are shown and synchrotron radiation effects are discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPJE034
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TUPJE042	Transverse Tunes Determination from Mixed BPM Data	1709
	P. Zisopoulos, F. Antoniou, Y. Papaphilippou CERN, Geneva, Switzerland E. Hertle, A.-S. Müller KIT, Eggenstein-Leopoldshafen, Germany
	Decoherence due to non-zero chromaticity and/or amplitude dependent tune-shift, but also damping mechanisms can affect the accurate tune determination by leaving a limited number of turns for frequency analysis of the turn by turn (TbT) position data. In order to by-pass these problems, Fourier analysis of mixed TBT data from all BPMs can be employed. The approach is applied in two different accelerators, a hadron collider as the LHC and a synchrotron light source as the ANKA storage ring. The impact in the accuracy of the method of missing BPM data is also discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPJE042
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TUPTY020	Building a Luminosity Model for the LHC and HL-LHC	2042
	F. Antoniou, G. Arduini, Y. Papaphilippou, G. Papotti CERN, Geneva, Switzerland
	One key objective of the High Luminosity LHC Upgrade is to determine a set of beam parameters and the hardware configuration that will enable the LHC to reach a peak luminosity of 5×10³⁴ cm^-2 s^-1 and ultimately 7.5x10³⁴ cm^-2 s^-1 with levelling, allowing an integrated luminosity of 250-300 fb^-1 per year. In order to determine the integrated performance it is important to develop a realistic model of the luminosity evolution during a physics fill. In this paper, the different mechanisms affecting luminosity lifetime in the LHC are discussed and a luminosity model is presented. The model is benchmarked with data from LHC Run I.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY020
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TUPTY022	Alternative Optics Design of the CLIC Damping Rings with Variable Dipole Bends and High-field Wigglers	2046
	P.S. Papadopoulou, F. Antoniou, Y. Papaphilippou CERN, Geneva, Switzerland
	The CLIC Damping Rings baseline design aims to reach an ultra-low horizontal normalised emittance of 500nm-rad at 2.86GeV, based on the combined effect of TME arc cells and high-field super-conducting damping wigglers, while keeping the ring as compact as possible. In this paper, an alternative design is described, based on TME cells with longitudinally variable bends and an optimized Nb3Sn high-field wiggler. The impact of these changes on ring optics parameters and the associated optimisation steps are detailed taking account the dominant effect of intrabeam scattering.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY022
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TUPTY057	Scenarios for Circular Gamma-Gamma Higgs Factories	2156
	F. Zimmermann, Y. Papaphilippou CERN, Geneva, Switzerland R. Aleksan CEA/DSM/IRFU, France A. Apyan NU, Evanston, Illinois, USA
	Funding: The research leading to these results has received partial funding from the European Commission under the FP7 Research Infrastructures project EuCARD-2, grant agreement no.312453. The Higgs boson can be produced directly in gamma-gamma collisions generated by laser Compton back scattering off 80-90 GeV electron or positron beams. We discuss options for realizing a gamma-gamma Higgs factory using a high-energy circular e⁺e⁻ collider, such as FCC-ee or CEPC, and/or its top-up injector ring, and compare the parameters and advantages of such a facility, including the expected performance, with those for a Higgs factory based on a recirculating linac, such as SAPPHiRE.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY057
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THPF100	Status of the ESSnuSB Accumulator	3942
	E.H.M. Wildner, B.J. Holzer, M. Martini, Y. Papaphilippou, H.O. Schönauer CERN, Geneva, Switzerland T.J.C. Ekelöf, M. Olvegård, R.J.M.Y. Ruber Uppsala University, Uppsala, Sweden M. Eshraqi ESS, Lund, Sweden
	The European Spallation Source (ESS) is a research center based on the world's most powerful neutron source currently under construction in Lund, Sweden. 2.0 GeV, 2.86 ms long proton pulses at 14 Hz are produced for the spallation facility (5MW on target). The possibility to pulse the linac at higher frequency to deliver, in parallel with the spallation neutron production, a very intense, cost effective, high performance neutrino beam. Short pulses on the target require an accumulator ring. The optimization of the accumulator lattice to store these high intensity beams from the linac (1.1x10¹⁵ protons per pulse) has to take into account the space available on the ESS site, transport of H⁻ beams (charge exchange injection), radiation and shielding needs. Space must be available in the ring for collimation and an RF system for the extraction gap and loss control. We present the status of the accumulator for ESS neutrino facility.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-THPF100
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Paper

Title

Page

Beam Dynamics Studies to Develop a High-energy Luminosity Model for the LHC

233

G. Campogiani
Rome University La Sapienza, Roma, Italy
Y. Papaphilippou
CERN, Geneva, Switzerland

Funding: support provided by the EPS-AG through the EPS-AG student grant program
Luminosity, the key figure of merit of a collider as the LHC, depends on the brightness of the colliding beams. This makes the intensity dependent beam-beam effect the dominant performance limiting factor at collision. The parasitic interactions due to the electromagnetic mutual influence of the beams in the interaction region of a collider induce a diffusive behaviour in the tails of the beam. The evolution of charge density distribution is studied to model the beam tails evolution in order to characterize beam lifetime and luminosity. To achieve this, tools are developed for tracking distributions of arbitrary number of single particles interacting with the opposing strong-beam, to analyse the halo formation processes due to the combined effect of beam-beam and machine non-linearities. This paper presents preliminary results of the simulations, both for the LHC Run I and nominal LHC parameters. The former will be used to benchmark simulations while the latter aims at supporting luminosity estimate for the Run II.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPWA050

Export •

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

MOPJE034

Low Emittance Tuning for the CLIC Damping Rings

356

J. Alabau-Gonzalvo, F. Antoniou, Y. Papaphilippou
CERN, Geneva, Switzerland

A study on the sensitivity of the CLIC Damping Ring lattice to different sources of misalignment is presented. Dipole and quadrupole rolls, quadrupole and sextupole vertical offsets are considered, as well as the impact of a finite BPM resolution. The result of this study defines a low emittance tuning procedure and establishes alignment tolerances to preserve the vertical emittance below the design value (1 pm·rad). Non-linear dynamics studies including dynamic aperture and frequency maps are shown and synchrotron radiation effects are discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPJE034

Export •

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

TUPJE042

Transverse Tunes Determination from Mixed BPM Data

1709

P. Zisopoulos, F. Antoniou, Y. Papaphilippou
CERN, Geneva, Switzerland
E. Hertle, A.-S. Müller
KIT, Eggenstein-Leopoldshafen, Germany

Decoherence due to non-zero chromaticity and/or amplitude dependent tune-shift, but also damping mechanisms can affect the accurate tune determination by leaving a limited number of turns for frequency analysis of the turn by turn (TbT) position data. In order to by-pass these problems, Fourier analysis of mixed TBT data from all BPMs can be employed. The approach is applied in two different accelerators, a hadron collider as the LHC and a synchrotron light source as the ANKA storage ring. The impact in the accuracy of the method of missing BPM data is also discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPJE042

Export •

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

TUPTY020

Building a Luminosity Model for the LHC and HL-LHC

2042

F. Antoniou, G. Arduini, Y. Papaphilippou, G. Papotti
CERN, Geneva, Switzerland

One key objective of the High Luminosity LHC Upgrade is to determine a set of beam parameters and the hardware configuration that will enable the LHC to reach a peak luminosity of 5×10³⁴ cm^-2 s^-1 and ultimately 7.5x10³⁴ cm^-2 s^-1 with levelling, allowing an integrated luminosity of 250-300 fb^-1 per year. In order to determine the integrated performance it is important to develop a realistic model of the luminosity evolution during a physics fill. In this paper, the different mechanisms affecting luminosity lifetime in the LHC are discussed and a luminosity model is presented. The model is benchmarked with data from LHC Run I.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY020

Export •

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

TUPTY022

Alternative Optics Design of the CLIC Damping Rings with Variable Dipole Bends and High-field Wigglers

2046

P.S. Papadopoulou, F. Antoniou, Y. Papaphilippou
CERN, Geneva, Switzerland

The CLIC Damping Rings baseline design aims to reach an ultra-low horizontal normalised emittance of 500nm-rad at 2.86GeV, based on the combined effect of TME arc cells and high-field super-conducting damping wigglers, while keeping the ring as compact as possible. In this paper, an alternative design is described, based on TME cells with longitudinally variable bends and an optimized Nb3Sn high-field wiggler. The impact of these changes on ring optics parameters and the associated optimisation steps are detailed taking account the dominant effect of intrabeam scattering.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY022

Export •

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

TUPTY057

Scenarios for Circular Gamma-Gamma Higgs Factories

2156

F. Zimmermann, Y. Papaphilippou
CERN, Geneva, Switzerland
R. Aleksan
CEA/DSM/IRFU, France
A. Apyan
NU, Evanston, Illinois, USA

Funding: The research leading to these results has received partial funding from the European Commission under the FP7 Research Infrastructures project EuCARD-2, grant agreement no.312453.
The Higgs boson can be produced directly in gamma-gamma collisions generated by laser Compton back scattering off 80-90 GeV electron or positron beams. We discuss options for realizing a gamma-gamma Higgs factory using a high-energy circular e⁺e⁻ collider, such as FCC-ee or CEPC, and/or its top-up injector ring, and compare the parameters and advantages of such a facility, including the expected performance, with those for a Higgs factory based on a recirculating linac, such as SAPPHiRE.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY057

Export •

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

THPF100

Status of the ESSnuSB Accumulator

3942

E.H.M. Wildner, B.J. Holzer, M. Martini, Y. Papaphilippou, H.O. Schönauer
CERN, Geneva, Switzerland
T.J.C. Ekelöf, M. Olvegård, R.J.M.Y. Ruber
Uppsala University, Uppsala, Sweden
M. Eshraqi
ESS, Lund, Sweden

The European Spallation Source (ESS) is a research center based on the world's most powerful neutron source currently under construction in Lund, Sweden. 2.0 GeV, 2.86 ms long proton pulses at 14 Hz are produced for the spallation facility (5MW on target). The possibility to pulse the linac at higher frequency to deliver, in parallel with the spallation neutron production, a very intense, cost effective, high performance neutrino beam. Short pulses on the target require an accumulator ring. The optimization of the accumulator lattice to store these high intensity beams from the linac (1.1x10¹⁵ protons per pulse) has to take into account the space available on the ESS site, transport of H⁻ beams (charge exchange injection), radiation and shielding needs. Space must be available in the ring for collimation and an RF system for the extraction gap and loss control. We present the status of the accumulator for ESS neutrino facility.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-THPF100

Export •

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