IPAC2011 - List of Authors (Jowett, J.M.)

Paper	Title	Page
TUPZ007	First Ion Collimation Commissioning Results at the LHC	1813
	G. Bellodi, R.W. Assmann, R. Bruce, M. Cauchi, J.M. Jowett, G. Valentino, D. Wollmann CERN, Geneva, Switzerland
	First commissioning of the LHC Pb ion beams to 1.38 A TeV energy was successfully achieved in November 2010. Ion collimation has been predicted to be less efficient than for protons at the LHC, because of the complexity of the physical processes involved: nuclear fragmentation and electromagnetic dissociation in the primary collimators creating fragments with a wide range of Z/A ratios, that are not intercepted by the secondary collimators but lost in the dispersion suppressor sections of the ring. In this article we present first comparisons of measured loss maps with theoretical predictions from simulation runs with the ICOSIM code. An extrapolation to define the ultimate intensity limit for Pb beams is attempted. The scope of possible improvements in collimation efficiency coming from the installation of new collimators in the cold dispersion suppressors and combined betatron and momentum cleaning is also explored.

TUPZ016	First Run of the LHC as a Heavy-ion Collider	1837
	J.M. Jowett, G. Arduini, R.W. Assmann, P. Baudrenghien, C. Carli, M. Lamont, M. Solfaroli Camillocci, J.A. Uythoven, W. Venturini Delsolaro, J. Wenninger CERN, Geneva, Switzerland
	A year of LHC operation typically consists of an extended run with colliding protons, ending with a month in which the LHC has to switch to its second role as a heavy ion collider and provide a useful integrated luminosity to three experiments. The first such run in November 2010 demonstrated that this is feasible. Commissioning was extremely rapid, with collisions of Pb nuclei achieved within 55 h of first injection. Stable beams for physics data-taking were declared a little over one day later and the final integrated luminosity substantially exceeded expectations.

TUPZ017	Luminosity and Beam Parameter Evolution for Lead Ion Beams in the LHC	1840
	J.M. Jowett, R. Bruce, T. Mertens CERN, Geneva, Switzerland
	Heavy ion beams in the LHC are subject to strong blow-up and debunching effects from intra-beam scattering and luminosity-driven beam losses. The large nuclear charge is at the origin of these effects, both in the cross sections for simple Coulomb scattering and the ultraperipheral interactions occurring in the collisions. We compare predictions from our models with data on luminosity, beam size and intensity evolution from the first heavy ion run of the LHC. This analysis has to take account of the varying capabilities of the LHC beam instrumentation between injection and collision energies.

TUPZ019	Transverse Emittance Preservation through the LHC Cycle	1843
	V. Kain, B. Goddard, B.J. Holzer, J.M. Jowett, M. Meddahi, T. Mertens, F. Roncarolo CERN, Geneva, Switzerland
	The preservation of the transverse emittance is crucial for luminosity performance. At the LHC design stage the total allowed emittance increase was set to 7% throughout the LHC cycle. The proton run in 2010 showed that the injectors can provide beams with smaller emittances than nominal and higher bunch intensities. The LHC parameters are well under control and the emittances are kept below nominal until physics. The LHC luminosity goals for the first year of running could therefore be achieved with fewer bunches than initially foreseen. This paper will report on the measured emittance growth at injection from the SPS and the evolution of the emittance through the entire LHC cycle. Sources and possible cures for the observed emittance growth will be discussed.

WEPS022	Ions for LHC: Performance of the Injector Chain	2529
	D. Manglunki, M. E. Angoletta, P. Baudrenghien, G. Bellodi, A. Blas, T. Bohl, C. Carli, E. Carlier, S. Cettour Cave, M. Chanel, K. Cornelis, H. Damerau, A. Findlay, S.S. Gilardoni, S. Hancock, J.M. Jowett, D. Kuchler, S. Maury, E. Métral, S. Pasinelli, M. Schokker, G. Tranquille, B. Vandorpe, U. Wehrle, J. Wenninger CERN, Geneva, Switzerland
	The first LHC Pb ion run took place at 1.38 A TeV/c per beam in autumn 2010. After a short period of running-in, the injector chain was able to fill the collider with up to 137 bunches per ring, with an intensity of 10⁸ Pb ions/bunch, about 50% higher than the design value. This yielded a luminosity of 3E25 Hz/cm², allowing the experiments to accumulate just under 10 inverse microbarn each during the four week run. We review the performance of the individual links of the injector chain, and address the main issues limiting the LHC luminosity, in view of reaching 10²6 Hz/cm² in 2011, and substantially beyond when the LHC energy increases after the long shutdown in 2013-14.

THPZ014	LHeC Lattice Design	3714
	M. Fitterer, O.S. Brüning, H. Burkhardt, B.J. Holzer, J.M. Jowett, K.H. Meß, T. Risselada CERN, Geneva, Switzerland M. Klein The University of Liverpool, Liverpool, United Kingdom A.-S. Müller KIT, Karlsruhe, Germany
	The Large Hadron Electron Collider (LHeC) aims at lepton-proton and lepton-nucleus collisions with centre of mass energies of 1-2 TeV at ep luminosities in excess of 10³3 cm^-2 s^-1. We present here a lattice design for the electron ring option, which meets the design parameters and also the constraints imposed by the integration of the new electron ring in the LHC tunnel.

Paper

Title

Page

First Ion Collimation Commissioning Results at the LHC

1813

G. Bellodi, R.W. Assmann, R. Bruce, M. Cauchi, J.M. Jowett, G. Valentino, D. Wollmann
CERN, Geneva, Switzerland

First commissioning of the LHC Pb ion beams to 1.38 A TeV energy was successfully achieved in November 2010. Ion collimation has been predicted to be less efficient than for protons at the LHC, because of the complexity of the physical processes involved: nuclear fragmentation and electromagnetic dissociation in the primary collimators creating fragments with a wide range of Z/A ratios, that are not intercepted by the secondary collimators but lost in the dispersion suppressor sections of the ring. In this article we present first comparisons of measured loss maps with theoretical predictions from simulation runs with the ICOSIM code. An extrapolation to define the ultimate intensity limit for Pb beams is attempted. The scope of possible improvements in collimation efficiency coming from the installation of new collimators in the cold dispersion suppressors and combined betatron and momentum cleaning is also explored.

TUPZ016

First Run of the LHC as a Heavy-ion Collider

1837

J.M. Jowett, G. Arduini, R.W. Assmann, P. Baudrenghien, C. Carli, M. Lamont, M. Solfaroli Camillocci, J.A. Uythoven, W. Venturini Delsolaro, J. Wenninger
CERN, Geneva, Switzerland

A year of LHC operation typically consists of an extended run with colliding protons, ending with a month in which the LHC has to switch to its second role as a heavy ion collider and provide a useful integrated luminosity to three experiments. The first such run in November 2010 demonstrated that this is feasible. Commissioning was extremely rapid, with collisions of Pb nuclei achieved within 55 h of first injection. Stable beams for physics data-taking were declared a little over one day later and the final integrated luminosity substantially exceeded expectations.

TUPZ017

Luminosity and Beam Parameter Evolution for Lead Ion Beams in the LHC

1840

J.M. Jowett, R. Bruce, T. Mertens
CERN, Geneva, Switzerland

Heavy ion beams in the LHC are subject to strong blow-up and debunching effects from intra-beam scattering and luminosity-driven beam losses. The large nuclear charge is at the origin of these effects, both in the cross sections for simple Coulomb scattering and the ultraperipheral interactions occurring in the collisions. We compare predictions from our models with data on luminosity, beam size and intensity evolution from the first heavy ion run of the LHC. This analysis has to take account of the varying capabilities of the LHC beam instrumentation between injection and collision energies.

TUPZ019

Transverse Emittance Preservation through the LHC Cycle

1843

V. Kain, B. Goddard, B.J. Holzer, J.M. Jowett, M. Meddahi, T. Mertens, F. Roncarolo
CERN, Geneva, Switzerland

The preservation of the transverse emittance is crucial for luminosity performance. At the LHC design stage the total allowed emittance increase was set to 7% throughout the LHC cycle. The proton run in 2010 showed that the injectors can provide beams with smaller emittances than nominal and higher bunch intensities. The LHC parameters are well under control and the emittances are kept below nominal until physics. The LHC luminosity goals for the first year of running could therefore be achieved with fewer bunches than initially foreseen. This paper will report on the measured emittance growth at injection from the SPS and the evolution of the emittance through the entire LHC cycle. Sources and possible cures for the observed emittance growth will be discussed.

WEPS022

Ions for LHC: Performance of the Injector Chain

2529

D. Manglunki, M. E. Angoletta, P. Baudrenghien, G. Bellodi, A. Blas, T. Bohl, C. Carli, E. Carlier, S. Cettour Cave, M. Chanel, K. Cornelis, H. Damerau, A. Findlay, S.S. Gilardoni, S. Hancock, J.M. Jowett, D. Kuchler, S. Maury, E. Métral, S. Pasinelli, M. Schokker, G. Tranquille, B. Vandorpe, U. Wehrle, J. Wenninger
CERN, Geneva, Switzerland

The first LHC Pb ion run took place at 1.38 A TeV/c per beam in autumn 2010. After a short period of running-in, the injector chain was able to fill the collider with up to 137 bunches per ring, with an intensity of 10⁸ Pb ions/bunch, about 50% higher than the design value. This yielded a luminosity of 3E25 Hz/cm², allowing the experiments to accumulate just under 10 inverse microbarn each during the four week run. We review the performance of the individual links of the injector chain, and address the main issues limiting the LHC luminosity, in view of reaching 10²6 Hz/cm² in 2011, and substantially beyond when the LHC energy increases after the long shutdown in 2013-14.

THPZ014

LHeC Lattice Design

3714

M. Fitterer, O.S. Brüning, H. Burkhardt, B.J. Holzer, J.M. Jowett, K.H. Meß, T. Risselada
CERN, Geneva, Switzerland
M. Klein
The University of Liverpool, Liverpool, United Kingdom
A.-S. Müller
KIT, Karlsruhe, Germany

The Large Hadron Electron Collider (LHeC) aims at lepton-proton and lepton-nucleus collisions with centre of mass energies of 1-2 TeV at ep luminosities in excess of 10³3 cm^-2 s^-1. We present here a lattice design for the electron ring option, which meets the design parameters and also the constraints imposed by the integration of the new electron ring in the LHC tunnel.