IPAC2013 - List of Authors (Lari, L.)

Paper

Title

Page

Simulations and Measurements of Cleaning with 100 MJ Beams in the LHC

52

R. Bruce, R.W. Aßmann, V. Boccone, C. Bracco, M. Cauchi, F. Cerutti, D. Deboy, A. Ferrari, L. Lari, A. Marsili, A. Mereghetti, E. Quaranta, S. Redaelli, G. Robert-Demolaize, A. Rossi, B. Salvachua, E. Skordis, G. Valentino, V. Vlachoudis, Th. Weiler, D. Wollmann
CERN, Geneva, Switzerland
L. Lari
IFIC, Valencia, Spain
E. Quaranta
Politecnico/Milano, Milano, Italy
G. Valentino
University of Malta, Information and Communication Technology, Msida, Malta

The CERN Large Hadron Collider is routinely storing proton beam intensities of more than 100 MJ, which puts extraordinary demands on the control of beam losses to avoid quenches of the superconducting magnets. Therefore, a detailed understanding of the LHC beam cleaning is required. We present tracking and shower simulations of the LHC's multi-stage collimation system and compare with measured beam losses, which allow us to conclude on the predictive power of the simulations.

Slides MOODB202 [6.343 MB]

MOPWO028

Recent Developments and Future Plans for SixTrack

948

R. De Maria, R. Bruce, R. Calaga, L. Deniau, M. Fjellstrom, M. Giovannozzi, L. Lari, Y.I. Levinsen, E. McIntosh, A. Mereghetti, D. Pastor Sinuela, S. Redaelli, H. Renshall, A. Rossi, F. Schmidt, R. Tomás, V. Vlachoudis
CERN, Geneva, Switzerland
R. Appleby, D.R. Brett
UMAN, Manchester, United Kingdom
D. Banfi, J. Barranco
EPFL, Lausanne, Switzerland
B. Dalena
CEA/IRFU, Gif-sur-Yvette, France
L. Lari
IFIC, Valencia, Spain
V. Previtali
Fermilab, Batavia, USA
G. Robert-Demolaize
BNL, Upton, Long Island, New York, USA

Funding: The HiLumi LHC Design Study is included in the HL-LHC project and is partly funded by the European Commission within the Framework Programme 7 Capacities Specific Programme, Grant Agreement 284404.
SixTrack is a symplectic 6D tracking code routinely used to simulate single particle trajectories in high energy circular machines like the LHC and RHIC. The paper presents the developments recently implemented and those foreseen for extending the physics models: exact Hamiltonian, different ions and charge states, RF multipoles, non-linear fringe fields, Taylor maps, e-lenses, ion scattering. Moreover new functionalities are also added like variable number of tracked particles, time dependent strengths, GPU computations with a refactoring of the core structure. The developments will benefit studies on the LHC and SPS, for collimation efficiency, ion operations, failure scenarios and HL-LHC design.

MOPWO031

High Energy Beam Impact Tests on a LHC Tertiary Collimator at CERN HiRadMat Facility

954

M. Cauchi, O. Aberle, R.W. Aßmann, A. Bertarelli, F. Carra, A. Dallocchio, D. Deboy, L. Lari, S. Redaelli, A. Rossi
CERN, Geneva, Switzerland
M. Cauchi, P. Mollicone
UoM, Msida, Malta
L. Lari
IFIC, Valencia, Spain
N.J. Sammut
University of Malta, Information and Communication Technology, Msida, Malta

The correct functioning of the collimation system is crucial to safely operate the LHC. The requirements to handle high intensity beams can be demanding. In this respect, investigating the consequences of LHC particle beams hitting tertiary collimators (TCTs) in the experimental regions is a fundamental issue for machine protection. An experimental test was designed to investigate the robustness and effects of beam accidents on a fully assembled collimator, based on accident scenarios in the LHC. This experiment, carried out at the CERN HiRadMat (High Irradiation to Materials) facility, involved 440 GeV beam impacts of different intensities on the jaws of a horizontal TCT. This paper presents the experimental setup and the preliminary results obtained together with some first outcomes from visual inspection.

MOPWO038

Cleaning Inefficiency of the LHC Collimation System during the Energy Ramp: Simulations and Measurements

975

E. Quaranta, R. Bruce, L. Lari, D. Mirarchi, S. Redaelli, A. Rossi, B. Salvachua, G. Valentino
CERN, Geneva, Switzerland
L. Lari
IFIC, Valencia, Spain
D. Mirarchi
The Imperial College of Science, Technology and Medicine, London, United Kingdom
G. Valentino
University of Malta, Information and Communication Technology, Msida, Malta

The cleaning inefficiency of the LHC collimation system has already been studied in detail at injection and top energy (450 GeV and 4 TeV respectively). In this paper the results are presented for the cleaning inefficiency at intermediate energies, simulated using the SixTrack code. The first comparisons with measured provoked losses are discussed. This study helps in benchmarking the energy dependence of the simulated inefficiency and is thus important for the extrapolation to future operation at higher energies.

MOPWO046

Simulations and Measurements of Beam Losses on LHC Collimators during Beam Abort Failures

996

L. Lari, C. Bracco, R. Bruce, B. Goddard, S. Redaelli, B. Salvachua, G. Valentino
CERN, Geneva, Switzerland
A. Faus-Golfe, L. Lari
IFIC, Valencia, Spain
G. Valentino
University of Malta, Information and Communication Technology, Msida, Malta

Funding: The HiLumi LHC Design Study is included in the HL-LHC project and is partly funded by the European Commission within the Framework Programme 7 Capacities Specific Programme, Grant Agreement 284404.
One of the main purposes of tracking simulations for collimation studies is to produce loss maps along the LHC ring, in order to identify the level of local beam losses during nominal and abnormal operation scenarios. The SixTrack program is the standard tracking tool used at CERN to perform these studies. Recently, it was expanded in order to evaluate the proton load on different collimators in case of fast beam failures. Simulations are compared with beam measurements at 4 TeV. Combined failures are assumed which provide worst-case scenarios of the load on tungsten tertiary collimators.

MOPWO047

Studies of Thermal Loads on Collimators for HL-LHC Optics in case of Fast Losses

999

L. Lari, R. Bruce, F. Cerutti
CERN, Geneva, Switzerland
L. Lari
IFIC, Valencia, Spain

Funding: The HiLumi LHC Design Study is included in the HL-LHC project and is partly funded by the European Commission within the Framework Programme 7 Capacities Specific Programme, Grant Agreement 284404.
The new layouts for the HL-LHC pose new challenges in terms of proton loads on the collimators around the ring, in particular for the ones of in experimental regions that become critical with squeeze optics. New layouts are under consideration, which foresee updated collimation schemes. Simulations of halo loads for in case of fast failures have been setup with SixTrack in order to determine beam loss distributions for realistic error scenarios. The particle tracking studies might then be interfaced to tools like FLUKA to evaluate the thermal loads on collimators in case of failures. In this paper, the preliminary studies performed for the baseline HL-LHC optics layouts are presented.

MOPWO048

Cleaning Performance of the LHC Collimation System up to 4 TeV

1002

B. Salvachua, R.W. Aßmann, R. Bruce, M. Cauchi, D. Deboy, L. Lari, A. Marsili, D. Mirarchi, E. Quaranta, S. Redaelli, A. Rossi, G. Valentino
CERN, Geneva, Switzerland
M. Cauchi
UoM, Msida, Malta
L. Lari
IFIC, Valencia, Spain
D. Mirarchi
The Imperial College of Science, Technology and Medicine, London, United Kingdom
G. Valentino
University of Malta, Information and Communication Technology, Msida, Malta

Funding: Research supported by EU FP7 HiLumi LHC (Grant agreement 284404)
In this paper we review the performance of the LHC collimation system during 2012 and compare it with previous years. During 2012, the so-called tight settings were deployed for a better cleaning and improved beta-star reach. As a result, a record cleaning efficiency below a few 0.0001 was achieved in the cold regions where the highest beam losses occur. The cleaning in other cold locations is typically a factor of 10 better. No quenches were observed during regular operation with up to 140 MJ stored beam energy. The system stability during the year, monitored regularly to ensure the system functionality for all machine configurations, and the performance of the alignment tools are also reviewed.

TUPME032

Update on Beam Induced RF Heating in the LHC

1646

B. Salvant, O. Aberle, G. Arduini, R.W. Aßmann, V. Baglin, M.J. Barnes, W. Bartmann, P. Baudrenghien, O.E. Berrig, A. Bertarelli, C. Bracco, E. Bravin, G. Bregliozzi, R. Bruce, F. Carra, F. Caspers, G. Cattenoz, S.D. Claudet, H.A. Day, M. Deile, J.F. Esteban Müller, P. Fassnacht, M. Garlaschè, L. Gentini, B. Goddard, A. Grudiev, B. Henrist, S. Jakobsen, O.R. Jones, O. Kononenko, G. Lanza, L. Lari, T. Mastoridis, V. Mertens, N. Mounet, E. Métral, A.A. Nosych, J.L. Nougaret, S. Persichelli, A.M. Piguiet, S. Redaelli, F. Roncarolo, G. Rumolo, B. Salvachua, M. Sapinski, R. Schmidt, E.N. Shaposhnikova, L.J. Tavian, M.A. Timmins, J.A. Uythoven, A. Vidal, J. Wenninger, D. Wollmann, M. Zerlauth
CERN, Geneva, Switzerland
H.A. Day
UMAN, Manchester, United Kingdom
L. Lari
IFIC, Valencia, Spain

Since June 2011, the rapid increase of the luminosity performance of the LHC has come at the expense of increased temperature and pressure readings on specific near-beam LHC equipment. In some cases, this beam induced heating has caused delays whilie equipment cools down, beam dumps and even degradation of these devices. This contribution gathers the observations of beam induced heating attributable to beam coupling impedance, their current level of understanding and possible actions that are planned to be implemented during the long shutdown in 2013-2014.

THPFI054

Preliminary Comparison of the Response of LHC Tertiary Collimators to Proton and Ion Beam Impacts

3412

M. Cauchi, R.W. Aßmann, A. Bertarelli, F. Carra, F. Cerutti, L. Lari
CERN, Geneva, Switzerland
M. Cauchi, P. Mollicone
UoM, Msida, Malta
L. Lari
IFIC, Valencia, Spain
N.J. Sammut
University of Malta, Information and Communication Technology, Msida, Malta

The CERN Large Hadron Collider is designed to bring into collision protons as well as heavy ions. Accidents involving impacts on collimators can happen for both species. The interaction of lead ions with matter differs to that of protons, thus making this scenario a new interesting case to study as it can result in different damage aspects on the collimator. This paper will present a preliminary comparison of the response of collimators to proton and ion beam impacts.

MOPWO028

Recent Developments and Future Plans for SixTrack

948

R. De Maria, R. Bruce, R. Calaga, L. Deniau, M. Fjellstrom, M. Giovannozzi, L. Lari, Y.I. Levinsen, E. McIntosh, A. Mereghetti, D. Pastor Sinuela, S. Redaelli, H. Renshall, A. Rossi, F. Schmidt, R. Tomás, V. Vlachoudis
CERN, Geneva, Switzerland
R. Appleby, D.R. Brett
UMAN, Manchester, United Kingdom
D. Banfi, J. Barranco
EPFL, Lausanne, Switzerland
B. Dalena
CEA/IRFU, Gif-sur-Yvette, France
L. Lari
IFIC, Valencia, Spain
V. Previtali
Fermilab, Batavia, USA
G. Robert-Demolaize
BNL, Upton, Long Island, New York, USA

Funding: The HiLumi LHC Design Study is included in the HL-LHC project and is partly funded by the European Commission within the Framework Programme 7 Capacities Specific Programme, Grant Agreement 284404.
SixTrack is a symplectic 6D tracking code routinely used to simulate single particle trajectories in high energy circular machines like the LHC and RHIC. The paper presents the developments recently implemented and those foreseen for extending the physics models: exact Hamiltonian, different ions and charge states, RF multipoles, non-linear fringe fields, Taylor maps, e-lenses, ion scattering. Moreover new functionalities are also added like variable number of tracked particles, time dependent strengths, GPU computations with a refactoring of the core structure. The developments will benefit studies on the LHC and SPS, for collimation efficiency, ion operations, failure scenarios and HL-LHC design.

MOPWO031

High Energy Beam Impact Tests on a LHC Tertiary Collimator at CERN HiRadMat Facility

954

M. Cauchi, O. Aberle, R.W. Aßmann, A. Bertarelli, F. Carra, A. Dallocchio, D. Deboy, L. Lari, S. Redaelli, A. Rossi
CERN, Geneva, Switzerland
M. Cauchi, P. Mollicone
UoM, Msida, Malta
L. Lari
IFIC, Valencia, Spain
N.J. Sammut
University of Malta, Information and Communication Technology, Msida, Malta

The correct functioning of the collimation system is crucial to safely operate the LHC. The requirements to handle high intensity beams can be demanding. In this respect, investigating the consequences of LHC particle beams hitting tertiary collimators (TCTs) in the experimental regions is a fundamental issue for machine protection. An experimental test was designed to investigate the robustness and effects of beam accidents on a fully assembled collimator, based on accident scenarios in the LHC. This experiment, carried out at the CERN HiRadMat (High Irradiation to Materials) facility, involved 440 GeV beam impacts of different intensities on the jaws of a horizontal TCT. This paper presents the experimental setup and the preliminary results obtained together with some first outcomes from visual inspection.

MOPWO038

Cleaning Inefficiency of the LHC Collimation System during the Energy Ramp: Simulations and Measurements

975

E. Quaranta, R. Bruce, L. Lari, D. Mirarchi, S. Redaelli, A. Rossi, B. Salvachua, G. Valentino
CERN, Geneva, Switzerland
L. Lari
IFIC, Valencia, Spain
D. Mirarchi
The Imperial College of Science, Technology and Medicine, London, United Kingdom
G. Valentino
University of Malta, Information and Communication Technology, Msida, Malta

The cleaning inefficiency of the LHC collimation system has already been studied in detail at injection and top energy (450 GeV and 4 TeV respectively). In this paper the results are presented for the cleaning inefficiency at intermediate energies, simulated using the SixTrack code. The first comparisons with measured provoked losses are discussed. This study helps in benchmarking the energy dependence of the simulated inefficiency and is thus important for the extrapolation to future operation at higher energies.

MOPWO046

Simulations and Measurements of Beam Losses on LHC Collimators during Beam Abort Failures

996

L. Lari, C. Bracco, R. Bruce, B. Goddard, S. Redaelli, B. Salvachua, G. Valentino
CERN, Geneva, Switzerland
A. Faus-Golfe, L. Lari
IFIC, Valencia, Spain
G. Valentino
University of Malta, Information and Communication Technology, Msida, Malta

Funding: The HiLumi LHC Design Study is included in the HL-LHC project and is partly funded by the European Commission within the Framework Programme 7 Capacities Specific Programme, Grant Agreement 284404.
One of the main purposes of tracking simulations for collimation studies is to produce loss maps along the LHC ring, in order to identify the level of local beam losses during nominal and abnormal operation scenarios. The SixTrack program is the standard tracking tool used at CERN to perform these studies. Recently, it was expanded in order to evaluate the proton load on different collimators in case of fast beam failures. Simulations are compared with beam measurements at 4 TeV. Combined failures are assumed which provide worst-case scenarios of the load on tungsten tertiary collimators.

MOPWO047

Studies of Thermal Loads on Collimators for HL-LHC Optics in case of Fast Losses

999

L. Lari, R. Bruce, F. Cerutti
CERN, Geneva, Switzerland
L. Lari
IFIC, Valencia, Spain

Funding: The HiLumi LHC Design Study is included in the HL-LHC project and is partly funded by the European Commission within the Framework Programme 7 Capacities Specific Programme, Grant Agreement 284404.
The new layouts for the HL-LHC pose new challenges in terms of proton loads on the collimators around the ring, in particular for the ones of in experimental regions that become critical with squeeze optics. New layouts are under consideration, which foresee updated collimation schemes. Simulations of halo loads for in case of fast failures have been setup with SixTrack in order to determine beam loss distributions for realistic error scenarios. The particle tracking studies might then be interfaced to tools like FLUKA to evaluate the thermal loads on collimators in case of failures. In this paper, the preliminary studies performed for the baseline HL-LHC optics layouts are presented.

MOPWO048

Cleaning Performance of the LHC Collimation System up to 4 TeV

1002

B. Salvachua, R.W. Aßmann, R. Bruce, M. Cauchi, D. Deboy, L. Lari, A. Marsili, D. Mirarchi, E. Quaranta, S. Redaelli, A. Rossi, G. Valentino
CERN, Geneva, Switzerland
M. Cauchi
UoM, Msida, Malta
L. Lari
IFIC, Valencia, Spain
D. Mirarchi
The Imperial College of Science, Technology and Medicine, London, United Kingdom
G. Valentino
University of Malta, Information and Communication Technology, Msida, Malta

Funding: Research supported by EU FP7 HiLumi LHC (Grant agreement 284404)
In this paper we review the performance of the LHC collimation system during 2012 and compare it with previous years. During 2012, the so-called tight settings were deployed for a better cleaning and improved beta-star reach. As a result, a record cleaning efficiency below a few 0.0001 was achieved in the cold regions where the highest beam losses occur. The cleaning in other cold locations is typically a factor of 10 better. No quenches were observed during regular operation with up to 140 MJ stored beam energy. The system stability during the year, monitored regularly to ensure the system functionality for all machine configurations, and the performance of the alignment tools are also reviewed.

TUPME032

Update on Beam Induced RF Heating in the LHC

1646

B. Salvant, O. Aberle, G. Arduini, R.W. Aßmann, V. Baglin, M.J. Barnes, W. Bartmann, P. Baudrenghien, O.E. Berrig, A. Bertarelli, C. Bracco, E. Bravin, G. Bregliozzi, R. Bruce, F. Carra, F. Caspers, G. Cattenoz, S.D. Claudet, H.A. Day, M. Deile, J.F. Esteban Müller, P. Fassnacht, M. Garlaschè, L. Gentini, B. Goddard, A. Grudiev, B. Henrist, S. Jakobsen, O.R. Jones, O. Kononenko, G. Lanza, L. Lari, T. Mastoridis, V. Mertens, N. Mounet, E. Métral, A.A. Nosych, J.L. Nougaret, S. Persichelli, A.M. Piguiet, S. Redaelli, F. Roncarolo, G. Rumolo, B. Salvachua, M. Sapinski, R. Schmidt, E.N. Shaposhnikova, L.J. Tavian, M.A. Timmins, J.A. Uythoven, A. Vidal, J. Wenninger, D. Wollmann, M. Zerlauth
CERN, Geneva, Switzerland
H.A. Day
UMAN, Manchester, United Kingdom
L. Lari
IFIC, Valencia, Spain

Since June 2011, the rapid increase of the luminosity performance of the LHC has come at the expense of increased temperature and pressure readings on specific near-beam LHC equipment. In some cases, this beam induced heating has caused delays whilie equipment cools down, beam dumps and even degradation of these devices. This contribution gathers the observations of beam induced heating attributable to beam coupling impedance, their current level of understanding and possible actions that are planned to be implemented during the long shutdown in 2013-2014.

THPFI054

Preliminary Comparison of the Response of LHC Tertiary Collimators to Proton and Ion Beam Impacts

3412

M. Cauchi, R.W. Aßmann, A. Bertarelli, F. Carra, F. Cerutti, L. Lari
CERN, Geneva, Switzerland
M. Cauchi, P. Mollicone
UoM, Msida, Malta
L. Lari
IFIC, Valencia, Spain
N.J. Sammut
University of Malta, Information and Communication Technology, Msida, Malta

The CERN Large Hadron Collider is designed to bring into collision protons as well as heavy ions. Accidents involving impacts on collimators can happen for both species. The interaction of lead ions with matter differs to that of protons, thus making this scenario a new interesting case to study as it can result in different damage aspects on the collimator. This paper will present a preliminary comparison of the response of collimators to proton and ion beam impacts.