IPAC2011 - List of Authors (Goddard, B.)

Paper	Title	Page
TUPC137	UFOs in the LHC	1347
	T. Baer, M.J. Barnes, B. Goddard, E.B. Holzer, J.M. Jimenez, A. Lechner, V. Mertens, E. Nebot Del Busto, A. Nordt, J.A. Uythoven, B. Velghe, J. Wenninger, F. Zimmermann CERN, Geneva, Switzerland
	One of the major known limitations for the performance of the Large Hadron Collider are so called UFOs (”Unidentified Falling Objects”). UFOs were first observed in July 2010 and have since caused numerous protection beam dumps. UFOs are thought to be micrometer sized dust particles which lead to fast beam losses with a duration of about 10 turns when they interact with the beam. In 2011, the diagnostics for such events was significantly improved which allows estimates of the properties, dynamics and production mechanisms of the dust particles. The state of knowledge and mitigation strategies are presented.

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.

WEPC175	FLUKA Studies of the Asynchronous Beam Dump Effects on LHC Point 6	2397
	R. Versaci, V. Boccone, B. Goddard, A. Mereghetti, R. Schmidt, V. Vlachoudis CERN, Geneva, Switzerland
	The LHC is a record-breaking machine for beam energy and intensity. An intense effort has therefore been deployed in simulating critical operational scenarios of energy deposition. FLUKA is the most widely used code for this kind of simulations at CERN because of the high reliability of its results and the ease to custom detailed simulations all along hundreds of meters of beam line. We have investigated the effects of an asynchronous beam dump on the LHC Point 6 where, beams with a stored energy of 360 MJ, can instantaneously release up to a few J cm^-3 in the cryogenic magnets which have a quench limit of the order of the mJ cm^-3. In the present paper we will briefly introduce FLUKA, describe the simulation approach, and discuss the evaluated maximum energy release onto the superconducting magnets during an asynchronous beam dump. We will then analyse the shielding provided by collimators installed in the area and discuss safety limits for the operation of the LHC.

WEPS017	Plans for the Upgrade of the LHC Injectors	2517
	R. Garoby, S.S. Gilardoni, B. Goddard, K. Hanke, M. Meddahi, M. Vretenar CERN, Geneva, Switzerland
	The LHC Injectors Upgrade (LIU) project has been launched at the end of 2010 to prepare the CERN accelerator complex for reliably providing beam with the challenging characteristics required by the high luminosity LHC until at least 2030. Based on the work already started on Linac4, PS Booster, PS and SPS, the LIU project coordinates studies and implementation, and interfaces with the High Luminosity LHC (HL-LHC) project which looks after the upgrade of the LHC itself, expected by the end of the present decade. The anticipated beam characteristics are described, as well as the status of the studies and the solutions envisaged for improving the injector performances.

WEPS101	Lattice Design of a RCS as Possible Alternative to the PS Booster Upgrade	2745
	M. Fitterer, M. Benedikt, H. Burkhardt, C. Carli, R. Garoby, B. Goddard, K. Hanke, H.O. Schönauer CERN, Geneva, Switzerland A.-S. Müller KIT, Karlsruhe, Germany
	In the framework of the LHC Injectors Upgrade (LIU) a new rapid cycling synchrotron as alternative to the PS Booster has been proposed. In this paper we present the lattice constraints and requirement as well as the current status of the RCS lattice design and beam dynamics studies.

WEPZ031	Accelerator Studies on a Possible Experiment on Proton-driven Plasma Wakefields at CERN	2832
	R.W. Assmann, I. Efthymiopoulos, S.D. Fartoukh, G. Geschonke, B. Goddard, C. Heßler, S. Hillenbrand, M. Meddahi, S. Roesler, F. Zimmermann CERN, Geneva, Switzerland A. Caldwell, G.X. Xia MPI-P, München, Germany P. Muggli MPI, Muenchen, Germany
	There has been a proposal by Caldwell et al to use proton beams as drivers for high energy linear colliders. An experimental test with CERN's proton beams is being studied. Such a test requires a transfer line for transporting the beam to the experiment, a focusing section for beam delivery into the plasma, the plasma cell and a downstream beam section for measuring the effects from the plasma and safe disposal of the beam. The work done at CERN towards the conceptual layout and design of such a test area is presented. A possible development of such a test area into a CERN test facility for high-gradient acceleration experiments is discussed.

TUPS026	Specification of New Vacuum Chambers for the LHC Experimental Interactions	1584
	R. Veness, R.W. Assmann, A. Ball, A. Behrens, C. Bracco, G. Bregliozzi, R. Bruce, H. Burkhardt, G. Corti, M.A. Gallilee, M. Giovannozzi, B. Goddard, D. Mergelkuhl, E. Métral, M. Nessi, W. Riegler, J. Wenninger CERN, Geneva, Switzerland N. Mounet, B. Salvant EPFL, Lausanne, Switzerland
	The apertures for the vacuum chambers at the interaction points inside the LHC experiments are key both to the safe operation of the LHC machine and to obtaining the best physics performance from the experiments. Following the successful startup of the LHC physics programme the ALICE, ATLAS and CMS experiments have launched projects to improve physics performance by adding detector layers closer to the beam. To achieve this they have requested smaller aperture vacuum chambers to be installed. The first periods of LHC operation have yielded much information both on the performance of the LHC and the stability and alignment of the experiments. In this paper, the new information relating to the aperture of these chambers is presented and a summary is made of analysis of parameters required to safely reduce the vacuum chambers apertures for the high-luminosity experiments ATLAS and CMS.

WEPS018	The Proposed CERN Proton-Synchrotron Upgrade Program	2520
	S.S. Gilardoni, S. Bart Pedersen, W. Bartmann, S. Bartolome, O.E. Berrig, C. Bertone, A. Blas, D. Bodart, J. Borburgh, R.J. Brown, A.C. Butterworth, M.C.L. Buzio, C. Carli, P. Chiggiato, H. Damerau, T. Dobers, R. Folch, R. Garoby, B. Goddard, M. Gourber-Pace, S. Hancock, M. Hourican, P. Le Roux, L.A. Lopez Hernandez, A. Masi, G. Metral, Y. Muttoni, E. Métral, M. Nonis, J. Pierlot, S. Pittet, C. Rossi, I. Ruehl, G. Rumolo, L. Sermeus, R.R. Steerenberg, M. Widorski CERN, Geneva, Switzerland
	In the framework of the High-Luminosity LHC project, the CERN Proton Synchrotron would require a major upgrade to match the future beam parameters requested as pre-injector of the collider. The different beam dynamics issues, from space-charge limitations to longitudinal instabilities are discussed, as well as the proposed technical solutions to overcome them, covering the increase of the injection energy to RF related improvements.

WEPS019	Study of a Rapid Cycling Synchrotron to Replace the CERN PS Booster	2523
	K. Hanke, O. Aberle, M. E. Angoletta, B. Balhan, W. Bartmann, M. Benedikt, J. Borburgh, D. Bozzini, C. Carli, P. Dahlen, T. Dobers, M. Fitterer, R. Garoby, S.S. Gilardoni, B. Goddard, J. Hansen, T. Hermanns, M. Hourican, S. Jensen, A. Kosmicki, L.A. Lopez Hernandez, M. Meddahi, B. Mikulec, A. Newborough, M. Nonis, S. Olek, M.M. Paoluzzi, S. Pittet, B. Puccio, V. Raginel, I. Ruehl, H.O. Schönauer, L. Sermeus, R.R. Steerenberg, J. Tan, J. Tückmantel, M. Vretenar, M. Widorski CERN, Geneva, Switzerland
	CERN’s proton injector chain is undergoing a massive consolidation and upgrade program in order to deliver beams meeting the needs of the LHC Luminosity Upgrade. As an alternative to the upgrade of the existing Proton Synchrotron Booster (PSB), the construction of a Rapid Cycling Synchrotron (RCS) has been studied. This machine would replace the PSB and deliver beams to the LHC as well as to CERN’s rich fixed-target physics program. This paper summarizes the outcome of the feasibility study along with a tentative RCS design.

THPS049	Feasibility Study of a CERN PS Injection at 2 GeV	3535
	J. Borburgh, S. Aumon, W. Bartmann, S.S. Gilardoni, B. Goddard, L. Sermeus, R.R. Steerenberg CERN, Geneva, Switzerland
	In the framework of the potential CERN PS Booster (PSB) energy upgrade, a study was initiated to look into the possibilities and constraints to inject protons into the PS at kinetic energies up to 2 GeV, for LHC type beams and other (high intensity) beams. This paper highlights the identified bottlenecks and potential solutions and addresses the resulting requirements for the hardware in the transfer line and injection region of the PS. In conjunction with the proposed upgrade of the PSB-PS transfer line hardware the optics can be changed for different cycles. Optics solutions optimized for the different requirements of LHC type and other beams are presented.

THPS052	Studies on Transverse Painting for H⁻ Injection into the PSB	3544
	C. Bracco, C. Carli, T. Fowler, B. Goddard, G. Gräwer, J.-B. Lallement, M. Martini, M. Scholz, W.J.M. Weterings CERN, Geneva, Switzerland
	Linac4 will inject 160 MeV H− ions in to the CERN PS Booster (PSB). This will allow to reduce space charge effects and increase beam intensity but will require a substantial upgrade of the injection region, with the implementation of a charge-exchange multi-turn injection scheme. The PSB has to provide beam to several users with different requirements in terms of beam intensity and emittance. Four kicker magnets (KSW), which are already installed in the PSB lattice, will be used to accomplish painting in the horizontal phase space to match the injected beams to the required emittances. Double linear functions, with varying slopes for each user, have been defined for the KSW generators waveforms according to detailed beam dynamic studies for all target intensities and emittances. Effect of space charge, injection offsets, dispersion and betatron mismatch have been taken into account. Preliminary studies have been carried out to evaluate how to obtain the required vertical emittance and the option of a transverse painting, also in the vertical plane, is explored.

THPS053	Results from the HiRadMat Primary Beam Line Commissioning	3547
	C. Heßler, M. Arruat, J. Bauche, K. Bestmann, J. Blanco, N. Conan, K. Cornelis, I. Efthymiopoulos, H. Gaillard, B. Goddard, D. Grenier, G.G. Gros, A. Habert, L.K. Jensen, V. Kain, G. Le Godec, M. Meddahi, S. Pelletier, P. Pepinster, B. Puccio, C. Theis, P. Trilhe, G. Vandoni, J. Wenninger CERN, Geneva, Switzerland
	The High Radiation to Materials facility (HiRadMat) is a new experimental area at CERN, for studies of the impact of high-intensity pulsed beams on accelerator components and materials. The beam is delivered from the SPS by a new primary beam line, which has been constructed during the 2010/11 winter technical stop. The paper summarizes the construction phase and describes the results from the beam line commissioning in spring 2011. Beam parameter and aperture measurements are presented, as well as steering tests. A special emphasis has been put on the handling of the exceptionally flexible beam line optics in the control system.

THPS054	Injection and Extraction Considerations for a 2 GeV RCS at CERN	3550
	W. Bartmann, B. Balhan, J. Borburgh, L. Ducimetière, M. Fitterer, B. Goddard, L. Sermeus CERN, Geneva, Switzerland
	Conceptual studies have been made for a 2 GeV RCS at CERN as a possible replacement of the four-ring PS Booster. The lattice design has to accommodate suitable straight sections for a 160 MeV H⁻ charge exchange injection system, and for a 2 GeV fast extraction system. The design constraints for the injection and extraction systems are described, together with the proposed concepts and potential equipment limitations. In particular, the features of different possible H⁻ injection configurations are compared.

THPS055	Controlling Beamloss at Injection into the LHC	3553
	B. Goddard, F. Alessio, W. Bartmann, P. Baudrenghien, V. Boccone, C. Bracco, M. Brugger, K. Cornelis, B. Dehning, A. Di Mauro, L.N. Drosdal, E.B. Holzer, W. Höfle, R. Jacobsson, V. Kain, M. Meddahi, V. Mertens, A. Nordt, J.A. Uythoven, D. Valuch, S. Weisz, E.N. del Busto CERN, Geneva, Switzerland R. Appleby UMAN, Manchester, United Kingdom
	Losses at injection into the superconducting LHC can adversely affect the machine performance in several important ways. The high injected beam intensity and energy mean that precautions must be taken against damage and quenches, including collimators placed close to the beam in the injection regions. Clean injection is essential, to avoid spurious signals on the sensitive beam loss monitoring system which will trigger beam dumps. In addition, the use of the two injection insertions to house downstream high energy physics experiments brings constraints on permitted beam loss levels. In this paper the sources of injection beam loss are discussed together with the contributing factors and various issues experienced in the first full year of LHC operation. Simulations are compared with measurement, and the implemented and planned mitigation measures and diagnostic improvements are described. An outlook for future LHC operation is given.

THPZ025	Stability of the LHC Transfer lines	3741
	V. Kain, W. Bartmann, C. Bracco, L.N. Drosdal, B. Goddard, M. Meddahi, J.A. Uythoven, J. Wenninger CERN, Geneva, Switzerland
	The LHC is filled from the SPS through two 3 km transfer lines. The injected beam parameters need to be well under control for luminosity performance, machine protection and operational efficiency. Small fractions of beam loss on the transfer line collimation system create showers which can trigger the sensitive LHC beam loss monitor system nearby and cause a beam abort during filling. The stability of the transfer line trajectory through the collimators is particularly critical in this respect. This paper will report on the transfer line trajectory stability during the proton run in 2011, correlations with injection losses, correction frequency and the most likely sources for the observed oscillations.

Paper

Title

Page

UFOs in the LHC

1347

T. Baer, M.J. Barnes, B. Goddard, E.B. Holzer, J.M. Jimenez, A. Lechner, V. Mertens, E. Nebot Del Busto, A. Nordt, J.A. Uythoven, B. Velghe, J. Wenninger, F. Zimmermann
CERN, Geneva, Switzerland

One of the major known limitations for the performance of the Large Hadron Collider are so called UFOs (”Unidentified Falling Objects”). UFOs were first observed in July 2010 and have since caused numerous protection beam dumps. UFOs are thought to be micrometer sized dust particles which lead to fast beam losses with a duration of about 10 turns when they interact with the beam. In 2011, the diagnostics for such events was significantly improved which allows estimates of the properties, dynamics and production mechanisms of the dust particles. The state of knowledge and mitigation strategies are presented.

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.

WEPC175

FLUKA Studies of the Asynchronous Beam Dump Effects on LHC Point 6

2397

R. Versaci, V. Boccone, B. Goddard, A. Mereghetti, R. Schmidt, V. Vlachoudis
CERN, Geneva, Switzerland

The LHC is a record-breaking machine for beam energy and intensity. An intense effort has therefore been deployed in simulating critical operational scenarios of energy deposition. FLUKA is the most widely used code for this kind of simulations at CERN because of the high reliability of its results and the ease to custom detailed simulations all along hundreds of meters of beam line. We have investigated the effects of an asynchronous beam dump on the LHC Point 6 where, beams with a stored energy of 360 MJ, can instantaneously release up to a few J cm^-3 in the cryogenic magnets which have a quench limit of the order of the mJ cm^-3. In the present paper we will briefly introduce FLUKA, describe the simulation approach, and discuss the evaluated maximum energy release onto the superconducting magnets during an asynchronous beam dump. We will then analyse the shielding provided by collimators installed in the area and discuss safety limits for the operation of the LHC.

WEPS017

Plans for the Upgrade of the LHC Injectors

2517

R. Garoby, S.S. Gilardoni, B. Goddard, K. Hanke, M. Meddahi, M. Vretenar
CERN, Geneva, Switzerland

The LHC Injectors Upgrade (LIU) project has been launched at the end of 2010 to prepare the CERN accelerator complex for reliably providing beam with the challenging characteristics required by the high luminosity LHC until at least 2030. Based on the work already started on Linac4, PS Booster, PS and SPS, the LIU project coordinates studies and implementation, and interfaces with the High Luminosity LHC (HL-LHC) project which looks after the upgrade of the LHC itself, expected by the end of the present decade. The anticipated beam characteristics are described, as well as the status of the studies and the solutions envisaged for improving the injector performances.

WEPS101

Lattice Design of a RCS as Possible Alternative to the PS Booster Upgrade

2745

M. Fitterer, M. Benedikt, H. Burkhardt, C. Carli, R. Garoby, B. Goddard, K. Hanke, H.O. Schönauer
CERN, Geneva, Switzerland
A.-S. Müller
KIT, Karlsruhe, Germany

In the framework of the LHC Injectors Upgrade (LIU) a new rapid cycling synchrotron as alternative to the PS Booster has been proposed. In this paper we present the lattice constraints and requirement as well as the current status of the RCS lattice design and beam dynamics studies.

WEPZ031

Accelerator Studies on a Possible Experiment on Proton-driven Plasma Wakefields at CERN

2832

R.W. Assmann, I. Efthymiopoulos, S.D. Fartoukh, G. Geschonke, B. Goddard, C. Heßler, S. Hillenbrand, M. Meddahi, S. Roesler, F. Zimmermann
CERN, Geneva, Switzerland
A. Caldwell, G.X. Xia
MPI-P, München, Germany
P. Muggli
MPI, Muenchen, Germany

There has been a proposal by Caldwell et al to use proton beams as drivers for high energy linear colliders. An experimental test with CERN's proton beams is being studied. Such a test requires a transfer line for transporting the beam to the experiment, a focusing section for beam delivery into the plasma, the plasma cell and a downstream beam section for measuring the effects from the plasma and safe disposal of the beam. The work done at CERN towards the conceptual layout and design of such a test area is presented. A possible development of such a test area into a CERN test facility for high-gradient acceleration experiments is discussed.

TUPS026

Specification of New Vacuum Chambers for the LHC Experimental Interactions

1584

R. Veness, R.W. Assmann, A. Ball, A. Behrens, C. Bracco, G. Bregliozzi, R. Bruce, H. Burkhardt, G. Corti, M.A. Gallilee, M. Giovannozzi, B. Goddard, D. Mergelkuhl, E. Métral, M. Nessi, W. Riegler, J. Wenninger
CERN, Geneva, Switzerland
N. Mounet, B. Salvant
EPFL, Lausanne, Switzerland

The apertures for the vacuum chambers at the interaction points inside the LHC experiments are key both to the safe operation of the LHC machine and to obtaining the best physics performance from the experiments. Following the successful startup of the LHC physics programme the ALICE, ATLAS and CMS experiments have launched projects to improve physics performance by adding detector layers closer to the beam. To achieve this they have requested smaller aperture vacuum chambers to be installed. The first periods of LHC operation have yielded much information both on the performance of the LHC and the stability and alignment of the experiments. In this paper, the new information relating to the aperture of these chambers is presented and a summary is made of analysis of parameters required to safely reduce the vacuum chambers apertures for the high-luminosity experiments ATLAS and CMS.

WEPS018

The Proposed CERN Proton-Synchrotron Upgrade Program

2520

S.S. Gilardoni, S. Bart Pedersen, W. Bartmann, S. Bartolome, O.E. Berrig, C. Bertone, A. Blas, D. Bodart, J. Borburgh, R.J. Brown, A.C. Butterworth, M.C.L. Buzio, C. Carli, P. Chiggiato, H. Damerau, T. Dobers, R. Folch, R. Garoby, B. Goddard, M. Gourber-Pace, S. Hancock, M. Hourican, P. Le Roux, L.A. Lopez Hernandez, A. Masi, G. Metral, Y. Muttoni, E. Métral, M. Nonis, J. Pierlot, S. Pittet, C. Rossi, I. Ruehl, G. Rumolo, L. Sermeus, R.R. Steerenberg, M. Widorski
CERN, Geneva, Switzerland

In the framework of the High-Luminosity LHC project, the CERN Proton Synchrotron would require a major upgrade to match the future beam parameters requested as pre-injector of the collider. The different beam dynamics issues, from space-charge limitations to longitudinal instabilities are discussed, as well as the proposed technical solutions to overcome them, covering the increase of the injection energy to RF related improvements.

WEPS019

Study of a Rapid Cycling Synchrotron to Replace the CERN PS Booster

2523

K. Hanke, O. Aberle, M. E. Angoletta, B. Balhan, W. Bartmann, M. Benedikt, J. Borburgh, D. Bozzini, C. Carli, P. Dahlen, T. Dobers, M. Fitterer, R. Garoby, S.S. Gilardoni, B. Goddard, J. Hansen, T. Hermanns, M. Hourican, S. Jensen, A. Kosmicki, L.A. Lopez Hernandez, M. Meddahi, B. Mikulec, A. Newborough, M. Nonis, S. Olek, M.M. Paoluzzi, S. Pittet, B. Puccio, V. Raginel, I. Ruehl, H.O. Schönauer, L. Sermeus, R.R. Steerenberg, J. Tan, J. Tückmantel, M. Vretenar, M. Widorski
CERN, Geneva, Switzerland

CERN’s proton injector chain is undergoing a massive consolidation and upgrade program in order to deliver beams meeting the needs of the LHC Luminosity Upgrade. As an alternative to the upgrade of the existing Proton Synchrotron Booster (PSB), the construction of a Rapid Cycling Synchrotron (RCS) has been studied. This machine would replace the PSB and deliver beams to the LHC as well as to CERN’s rich fixed-target physics program. This paper summarizes the outcome of the feasibility study along with a tentative RCS design.

THPS049

Feasibility Study of a CERN PS Injection at 2 GeV

3535

J. Borburgh, S. Aumon, W. Bartmann, S.S. Gilardoni, B. Goddard, L. Sermeus, R.R. Steerenberg
CERN, Geneva, Switzerland

In the framework of the potential CERN PS Booster (PSB) energy upgrade, a study was initiated to look into the possibilities and constraints to inject protons into the PS at kinetic energies up to 2 GeV, for LHC type beams and other (high intensity) beams. This paper highlights the identified bottlenecks and potential solutions and addresses the resulting requirements for the hardware in the transfer line and injection region of the PS. In conjunction with the proposed upgrade of the PSB-PS transfer line hardware the optics can be changed for different cycles. Optics solutions optimized for the different requirements of LHC type and other beams are presented.

THPS052

Studies on Transverse Painting for H⁻ Injection into the PSB

3544

C. Bracco, C. Carli, T. Fowler, B. Goddard, G. Gräwer, J.-B. Lallement, M. Martini, M. Scholz, W.J.M. Weterings
CERN, Geneva, Switzerland

Linac4 will inject 160 MeV H− ions in to the CERN PS Booster (PSB). This will allow to reduce space charge effects and increase beam intensity but will require a substantial upgrade of the injection region, with the implementation of a charge-exchange multi-turn injection scheme. The PSB has to provide beam to several users with different requirements in terms of beam intensity and emittance. Four kicker magnets (KSW), which are already installed in the PSB lattice, will be used to accomplish painting in the horizontal phase space to match the injected beams to the required emittances. Double linear functions, with varying slopes for each user, have been defined for the KSW generators waveforms according to detailed beam dynamic studies for all target intensities and emittances. Effect of space charge, injection offsets, dispersion and betatron mismatch have been taken into account. Preliminary studies have been carried out to evaluate how to obtain the required vertical emittance and the option of a transverse painting, also in the vertical plane, is explored.

THPS053

Results from the HiRadMat Primary Beam Line Commissioning

3547

C. Heßler, M. Arruat, J. Bauche, K. Bestmann, J. Blanco, N. Conan, K. Cornelis, I. Efthymiopoulos, H. Gaillard, B. Goddard, D. Grenier, G.G. Gros, A. Habert, L.K. Jensen, V. Kain, G. Le Godec, M. Meddahi, S. Pelletier, P. Pepinster, B. Puccio, C. Theis, P. Trilhe, G. Vandoni, J. Wenninger
CERN, Geneva, Switzerland

The High Radiation to Materials facility (HiRadMat) is a new experimental area at CERN, for studies of the impact of high-intensity pulsed beams on accelerator components and materials. The beam is delivered from the SPS by a new primary beam line, which has been constructed during the 2010/11 winter technical stop. The paper summarizes the construction phase and describes the results from the beam line commissioning in spring 2011. Beam parameter and aperture measurements are presented, as well as steering tests. A special emphasis has been put on the handling of the exceptionally flexible beam line optics in the control system.

THPS054

Injection and Extraction Considerations for a 2 GeV RCS at CERN

3550

W. Bartmann, B. Balhan, J. Borburgh, L. Ducimetière, M. Fitterer, B. Goddard, L. Sermeus
CERN, Geneva, Switzerland

Conceptual studies have been made for a 2 GeV RCS at CERN as a possible replacement of the four-ring PS Booster. The lattice design has to accommodate suitable straight sections for a 160 MeV H⁻ charge exchange injection system, and for a 2 GeV fast extraction system. The design constraints for the injection and extraction systems are described, together with the proposed concepts and potential equipment limitations. In particular, the features of different possible H⁻ injection configurations are compared.

THPS055

Controlling Beamloss at Injection into the LHC

3553

B. Goddard, F. Alessio, W. Bartmann, P. Baudrenghien, V. Boccone, C. Bracco, M. Brugger, K. Cornelis, B. Dehning, A. Di Mauro, L.N. Drosdal, E.B. Holzer, W. Höfle, R. Jacobsson, V. Kain, M. Meddahi, V. Mertens, A. Nordt, J.A. Uythoven, D. Valuch, S. Weisz, E.N. del Busto
CERN, Geneva, Switzerland
R. Appleby
UMAN, Manchester, United Kingdom

Losses at injection into the superconducting LHC can adversely affect the machine performance in several important ways. The high injected beam intensity and energy mean that precautions must be taken against damage and quenches, including collimators placed close to the beam in the injection regions. Clean injection is essential, to avoid spurious signals on the sensitive beam loss monitoring system which will trigger beam dumps. In addition, the use of the two injection insertions to house downstream high energy physics experiments brings constraints on permitted beam loss levels. In this paper the sources of injection beam loss are discussed together with the contributing factors and various issues experienced in the first full year of LHC operation. Simulations are compared with measurement, and the implemented and planned mitigation measures and diagnostic improvements are described. An outlook for future LHC operation is given.

THPZ025

Stability of the LHC Transfer lines

3741

V. Kain, W. Bartmann, C. Bracco, L.N. Drosdal, B. Goddard, M. Meddahi, J.A. Uythoven, J. Wenninger
CERN, Geneva, Switzerland

The LHC is filled from the SPS through two 3 km transfer lines. The injected beam parameters need to be well under control for luminosity performance, machine protection and operational efficiency. Small fractions of beam loss on the transfer line collimation system create showers which can trigger the sensitive LHC beam loss monitor system nearby and cause a beam abort during filling. The stability of the transfer line trajectory through the collimators is particularly critical in this respect. This paper will report on the transfer line trajectory stability during the proton run in 2011, correlations with injection losses, correction frequency and the most likely sources for the observed oscillations.