IPAC2013 - List of Authors (Bartosik, H.)

Paper

Title

Page

Beam Transfer to LHC with the Low Gamma-transition SPS Optics

419

G. Vanbavinckhove, W. Bartmann, H. Bartosik, C. Bracco, L.N. Drøsdal, B. Goddard, V. Kain, M. Meddahi, V. Mertens, Y. Papaphilippou, J.A. Uythoven, J. Wenninger
CERN, Geneva, Switzerland
E. Gianfelice-Wendt
Fermilab, Batavia, USA

A new low gamma-transition optics with a lower integer tune, was introduced in the SPS to improve beam stability at high intensity. For transferring the beam to the LHC, the extraction bumps, extraction kickers and transfer lines needed to be adapted to the new optics. In particular, the transfer lines were re-matched and re-commissioned with the new optics. The first operational results are discussed for the SPS extraction, the transfer lines and the LHC injection. A detailed comparison is presented between the old and the new optics of the trajectories, dispersion, losses and other performance aspects.

MOPWO033

Analysis of LHC Transfer Line Trajectory Drifts

960

L.N. Drøsdal, W. Bartmann, H. Bartosik, C. Bracco, B. Goddard, V. Kain, Y. Papaphilippou, J.A. Uythoven, G. Vanbavinckhove, J. Wenninger
CERN, Geneva, Switzerland
E. Gianfelice-Wendt
Fermilab, Batavia, USA

The LHC is filled from the SPS via two 3km long transfer lines. In the first years of LHC operation large trajectory variations were discovered. The sources of bunch-by-bunch and shot-by-shot trajectory variations had been identified and improved by the 2012 LHC run. The origins of the longer term drifts were however still unclear and significant time was spent correcting the trajectories. In the last part of the 2012 run the optics in the SPS was changed to lower transition energy. Trajectory stability and correction frequency will be compared between before and after the optics change in the SPS. The sources of the variations have now been identified and will be discussed in this paper. Remedies for operation after the long shutdown will be proposed.

TUPFI002

Electron Cloud and Scrubbing Studies for the LHC

1331

G. Iadarola
Naples University Federico II, Science and Technology Pole, Napoli, Italy
G. Arduini, V. Baglin, H. Bartosik, C.O. Domínguez, J.F. Esteban Müller, G. Iadarola, G. Rumolo, E.N. Shaposhnikova, L.J. Tavian, F. Zimmermann
CERN, Geneva, Switzerland
C.O. Domínguez
EPFL, Lausanne, Switzerland
G.H.I. Maury Cuna
CINVESTAV, Mexico City, Mexico

Electron cloud build-up resulting from beam-induced multipacting is one of the major limitations for the operation of the LHC with beams with close bunch spacing. Electron clouds induce unwanted pressure rise, heat loads on the beam screens of the superconducting magnets and beam instabilities. Operation with bunch spacing of 50 ns in 2011 and 2012 has required decreasing the Secondary Electron Yield of the beam screens below the multipacting threshold for beams with this bunch spacing. This was achieved by continuous electron bombardment induced by operating the machine with high intensity beams with 50 and 25 ns spacing during dedicated periods at injection energy (450 GeV) and at top energy (3.5 and 4 TeV). The evolution of the Secondary Electron Yield during these periods, at different sections of the machine, can be estimated by pressure, heat load and by bunch-by-bunch RF stable phase measurements. The experimental information on the scrubbing process will be discussed and a possible “scrubbing strategy” to allow the operation with 50ns and 25ns beams after the Long Shutdown in 2013-2014 will be presented.

TUPME034

Experimental Studies for Future LHC Beams in the SPS

1652

H. Bartosik, T. Argyropoulos, T. Bohl, S. Cettour-Cave, J.F. Esteban Müller, W. Höfle, G. Iadarola, Y. Papaphilippou, G. Rumolo, B. Salvant, F. Schmidt, E.N. Shaposhnikova, H. Timko
CERN, Geneva, Switzerland
A.Y. Molodozhentsev
KEK, Ibaraki, Japan

The High Luminosity LHC (HL-LHC) project requires significantly higher beam intensity than presently accessible in the LHC injector chain. The aim of the LHC injectors upgrade project (LIU) is to prepare the CERN accelerators for the future needs of the LHC. Therefore a series of machine studies with high brightness beams were performed, assessing the present performance reach and identifying remaining limitations. Of particular concern are beam loading and longitudinal instabilities at high energy, space charge for beams with 50ns bunch spacing and electron cloud effects for beams with 25ns bunch spacing. This paper provides a summary of the performed studies, that have been possible thanks to the implementation of the SPS low gamma-transition optics.

TUPME046

Performance of SPS Low Transition Energy Optics for LHC Ion Beams

1667

F. Antoniou, G. Arduini, H. Bartosik, T. Bohl, S. Cettour Cave, K. Cornelis, D. Manglunki, Y. Papaphilippou
CERN, Geneva, Switzerland

An optics with low transition energy has been developed in the SPS for removing intensity limitations of the LHC proton beam and has become operational towards the second part of the 2012 LHC proton run. This optics was also used for filling the LHC with lead ions during the p/Pb run of the beginning of 2013. The impact of this optics in the performance of the LHC ion beam is studied here, especially with respect to collective effects, at the SPS injection energy. In particular, the potential gain of the increased beam sizes provided by this optics, with respect to losses and emittance blow up due to space-charge and Intrabeam Scattering (IBS) is evaluated. The measured lifetime is compared with the one provided by the Touschek effect and its interplay with RF noise is studied. The models are supported by measurements in the SPS and in the LHC flat bottom.

TUPWA049

Short High-Intensity Bunches for Plasma Wakefield Experiment AWAKE in the CERN SPS

1820

H. Timko, T. Argyropoulos, H. Bartosik, T. Bohl, J.F. Esteban Müller, E.N. Shaposhnikova
CERN, Geneva, Switzerland
A.V. Petrenko
BINP SB RAS, Novosibirsk, Russia

Obtaining the shortest possible bunch length in combination with the smallest transverse emittances and highest bunch intensity – this is the wish list of the proton-bunch driven, plasma wakefield acceleration experiment AWAKE currently under feasibility study at CERN. A few measurement sessions were conducted to determine the achievable bunch properties and their reproducibility. To obtain a short bunch length, the bunches were rotated in longitudinal phase space using the maximum available RF voltage prior to extraction. Measurements were carried out in two optics with different transition energies. The main performance limitation is longitudinal beam instability that develops during the acceleration ramp. With lower transition energy, beam stability is improved, but the bucket area is smaller for the same voltage. Based on the results obtained, we shall discuss the choice of optics, the impact of longitudinal instabilities, the importance of reproducibility, as well as options for improving the bunch parameters.

WEXB101

Optics Optimization for Reducing Collective Effects and Raising Instability Thresholds in Lepton and Hadron Rings

2033

Y. Papaphilippou, F. Antoniou, H. Bartosik
CERN, Geneva, Switzerland

This paper covers recent progress in the design of optics solutions to minimize collective effects such as beam instabilities, intra-beam scattering or space charge in hadron and lepton rings. The necessary steps are reviewed for designing the optics of high-intensity and high-brightness synchrotrons but also ultra-low emittance lepton storage rings, whose performance is strongly dominated by collective effects. Particular emphasis is given to proposed and existing designs illustrated by simulations and beam measurements.

Slides WEXB101 [24.511 MB]

WEPEA014

Recent Electron Cloud Studies in the SPS

2525

G. Iadarola, H. Bartosik, M. Driss Mensi, H. Neupert, G. Rumolo, M. Taborelli
CERN, Geneva, Switzerland
G. Iadarola
Naples University Federico II, Science and Technology Pole, Napoli, Italy

It is important to qualify the present status of the SPS with respect to the electron cloud before the Long Shutdown of the CERN accelerator complex, which will take place in 2013-2014. Therefore several electron cloud studies were performed during the 2012 run in order to get a full characterization of the behavior of the SPS with the LHC-type beams with 25 ns bunch spacing, which can be very sensitive to electron cloud effects. The collected information should allow to understand up to which extent this long period without beam operation - and the related interventions on the machine - will degrade the present conditioning state of the SPS, which has been achieved by “scrubbing” over several years. Several measurements with different beam conditions have been collected also on the electron cloud detectors installed in the machine. These results, in combination with detailed simulation studies, will provide the basis for defining strategies of electron cloud mitigation as required for the production of future high intensity and high brightness beams within the LHC Injectors Upgrade (LIU) project.

WEPEA053

Progress with the Upgrade of the SPS for the HL-LHC Era

2624

B. Goddard, T. Argyropoulos, W. Bartmann, H. Bartosik, T. Bohl, F. Caspers, K. Cornelis, H. Damerau, L.N. Drøsdal, L. Ducimetière, J.F. Esteban Müller, R. Garoby, M. Gourber-Pace, W. Höfle, G. Iadarola, L.K. Jensen, V. Kain, R. Losito, M. Meddahi, A. Mereghetti, V. Mertens, Ö. Mete, E. Montesinos, Y. Papaphilippou, G. Rumolo, B. Salvant, E.N. Shaposhnikova, M. Taborelli, H. Timko, F.M. Velotti
CERN, Geneva, Switzerland
E. Gianfelice-Wendt
Fermilab, Batavia, USA

The demanding beam performance requirements of the HL-LHC project translate into a set of requirements and upgrade paths for the LHC injector complex. In this paper the performance requirements for the SPS and the known limitations are reviewed in the light of the 2012 operational experience. The various SPS upgrades in progress and still under consideration are described, in addition to the machine studies and simulations performed in 2012. The expected machine performance reach is estimated on the basis of the present knowledge, and the remaining decisions that still need to be made concerning upgrade options are detailed.

WEPEA056

Design and Beam Measurements of Modified Fast Extraction Schemes in the CERN PS for Installing a Dummy Septum to Mitigate Ring Irradiation

2633

C. Hernalsteens, H. Bartosik, L.N. Drøsdal, S.S. Gilardoni, M. Giovannozzi, A. Lachaize, Y. Papaphilippou, A. Ulsroed
CERN, Geneva, Switzerland

The proposed Multi-Turn Extraction (MTE) for the CERN PS allows to reduce the overall extraction losses for high intensity beams. The required longitudinal structure of the proton beam induces unavoidable beam losses at the magnetic extraction septum. The installation of a dummy septum with an appropriate shielding has been proposed to localise losses and to shadow the magnetic septum. Such a device, located in the extraction region, imposes tight constraints on the available beam aperture. Modified extraction schemes have been proposed and in this paper they will be presented and discussed in detail together with the measured performance.

WEPEA060

Plans for the Upgrade of CERN's Heavy Ion Complex

2645

D. Manglunki, M. E. Angoletta, H. Bartosik, A. Blas, D. Bodart, M.A. Bodendorfer, T. Bohl, J. Borburgh, E. Carlier, J.-M. Cravero, H. Damerau, L. Ducimetière, A. Findlay, R. Garoby, S.S. Gilardoni, B. Goddard, S. Hancock, E.B. Holzer, J.M. Jowett, T. Kramer, D. Kuchler, A.M. Lombardi, Y. Papaphilippou, S. Pasinelli, R. Scrivens, G. Tranquille
CERN, Geneva, Switzerland

To reach a luminosity higher than 6×10²⁷ Hz/cm² for Pb-Pb collisions, as expected by the ALICE experiment after its upgrade during the 2nd Long LHC Shutdown (LS2), several upgrades will have to be performed in the CERN accelerator complex, from the source to the LHC itself. This paper first details the present limitations and then describes the strategy for the different machines in the ion injector chain. Both filling schemes and possible hardware upgrades are discussed.

WEPEA061

The First LHC p-Pb run: Performance of the Heavy Ion Production Complex

2648

D. Manglunki, M. E. Angoletta, H. Bartosik, G. Bellodi, A. Blas, M.A. Bodendorfer, T. Bohl, C. Carli, E. Carlier, S. Cettour Cave, K. Cornelis, H. Damerau, A. Findlay, S.S. Gilardoni, S. Hancock, J.M. Jowett, D. Kuchler, M. O'Neil, Y. Papaphilippou, S. Pasinelli, R. Scrivens, G. Tranquille, B. Vandorpe, U. Wehrle, J. Wenninger
CERN, Geneva, Switzerland

TThe first LHC proton-ion run took place in January-February 2013; it was the first extension to the collider programme, as this mode was not included in the design report. This paper presents the performance of the heavy ion and proton production complex, and details the issues encountered, in particular the creation of the same bunch pattern in both beams.

WEPME060

First Results and Analysis of the Performance of a 4 GS/s Intra-bunch Vertical Feedback System at the SPS

3070

J.M. Cesaratto, J.E. Dusatko, J.D. Fox, J.J. Olsen, K.M. Pollock, C.H. Rivetta, O. Turgut
SLAC, Menlo Park, California, USA
H. Bartosik, W. Höfle, G. Kotzian, U. Wehrle
CERN, Geneva, Switzerland

Funding: Work supported by the U.S. Department of Energy under contract DE-AC02-76SF00515 and the US LHC Accelerator Research program ( LARP)
We present experimental measurements taken from SPS machine development studies with an intra-bunch feedback channel. These studies use a digital signal processing system to implement general-purpose control algorithms on multiple samples across a single SPS bunch ( for ease of synchronization with the SPS RF frequency a sampling frequency of 3.2 GS/sec. is implemented). These initial studies concentrate on single-bunch motion, and study the vertical betatron motion as the feedback control is varied. The studies are focused on validating simulation models of the beam dynamics with feedback. Time and frequency domain results include excitation and damping of intra-bunch motion with positive and negative feedback. We present an overview of the challenges of intra-bunch feedback, and highlight methods to time-align the pickup and kicker signals within the closed-loop feedback channel.

THOBB102

Beam Coupling Impedance Localization Technique Validation and Measurements in the CERN Machines

3106

N. Biancacci, G. Arduini, T. Argyropoulos, H. Bartosik, R. Calaga, K. Cornelis, S.S. Gilardoni, N. Mounet, E. Métral, Y. Papaphilippou, S. Persichelli, G. Rumolo, B. Salvant, G. Sterbini, R. Tomás, R. Wasef
CERN, Geneva, Switzerland
M. Migliorati, L. Palumbo
URLS, Rome, Italy

The beam coupling impedance could lead to limitations in beam brightness and quality, and therefore it needs accurate quantification and continuous monitoring in order to detect and mitigate high impedance sources. In the CERN machines, for example, kickers and collimators are expected to be the main contributors to the total imaginary part of the transverse impedance. In order to detect the other sources, a beam based measurement was developed: from the variation of betatron phase beating with intensity, it is possible to detect the locations of main impedance sources. In this work we present the application of the method with beam measurements in the CERN PS, SPS and LHC.

Slides THOBB102 [7.224 MB]

THPWO080

Operational Performance of the LHC Proton Beams with the SPS Low Transition Energy Optics

3945

Y. Papaphilippou, G. Arduini, T. Argyropoulos, W. Bartmann, H. Bartosik, T. Bohl, C. Bracco, S. Cettour-Cave, K. Cornelis, L.N. Drøsdal, J.F. Esteban Müller, B. Goddard, A. Guerrero, W. Höfle, V. Kain, G. Rumolo, B. Salvant, E.N. Shaposhnikova, H. Timko, D. Valuch, G. Vanbavinckhove, J. Wenninger
CERN, Geneva, Switzerland
E. Gianfelice-Wendt
Fermilab, Batavia, USA

An optics in the SPS with lower integer tunes (20 versus 26) was proposed and introduced in machine studies since 2010, as a measure for increasing transverse and longitudinal instability thresholds, especially at low energy, for the LHC proton beams. After two years of machine studies and careful optimisation, the new “Q20” optics became operational in September 2012 and steadily delivered beam to the LHC until the end of the run. This paper reviews the operational performance of the Q20 optics with respect to transverse and longitudinal beam characteristics in the SPS, enabling high brightness beams injected into the LHC. Aspects of longitudinal beam stability, transmission, high-energy orbit control and beam transfer are discussed.

Paper	Title	Page
MOPFI060	Beam Transfer to LHC with the Low Gamma-transition SPS Optics	419
	G. Vanbavinckhove, W. Bartmann, H. Bartosik, C. Bracco, L.N. Drøsdal, B. Goddard, V. Kain, M. Meddahi, V. Mertens, Y. Papaphilippou, J.A. Uythoven, J. Wenninger CERN, Geneva, Switzerland E. Gianfelice-Wendt Fermilab, Batavia, USA
	A new low gamma-transition optics with a lower integer tune, was introduced in the SPS to improve beam stability at high intensity. For transferring the beam to the LHC, the extraction bumps, extraction kickers and transfer lines needed to be adapted to the new optics. In particular, the transfer lines were re-matched and re-commissioned with the new optics. The first operational results are discussed for the SPS extraction, the transfer lines and the LHC injection. A detailed comparison is presented between the old and the new optics of the trajectories, dispersion, losses and other performance aspects.

MOPWO033	Analysis of LHC Transfer Line Trajectory Drifts	960
	L.N. Drøsdal, W. Bartmann, H. Bartosik, C. Bracco, B. Goddard, V. Kain, Y. Papaphilippou, J.A. Uythoven, G. Vanbavinckhove, J. Wenninger CERN, Geneva, Switzerland E. Gianfelice-Wendt Fermilab, Batavia, USA
	The LHC is filled from the SPS via two 3km long transfer lines. In the first years of LHC operation large trajectory variations were discovered. The sources of bunch-by-bunch and shot-by-shot trajectory variations had been identified and improved by the 2012 LHC run. The origins of the longer term drifts were however still unclear and significant time was spent correcting the trajectories. In the last part of the 2012 run the optics in the SPS was changed to lower transition energy. Trajectory stability and correction frequency will be compared between before and after the optics change in the SPS. The sources of the variations have now been identified and will be discussed in this paper. Remedies for operation after the long shutdown will be proposed.

TUPFI002	Electron Cloud and Scrubbing Studies for the LHC	1331
	G. Iadarola Naples University Federico II, Science and Technology Pole, Napoli, Italy G. Arduini, V. Baglin, H. Bartosik, C.O. Domínguez, J.F. Esteban Müller, G. Iadarola, G. Rumolo, E.N. Shaposhnikova, L.J. Tavian, F. Zimmermann CERN, Geneva, Switzerland C.O. Domínguez EPFL, Lausanne, Switzerland G.H.I. Maury Cuna CINVESTAV, Mexico City, Mexico
	Electron cloud build-up resulting from beam-induced multipacting is one of the major limitations for the operation of the LHC with beams with close bunch spacing. Electron clouds induce unwanted pressure rise, heat loads on the beam screens of the superconducting magnets and beam instabilities. Operation with bunch spacing of 50 ns in 2011 and 2012 has required decreasing the Secondary Electron Yield of the beam screens below the multipacting threshold for beams with this bunch spacing. This was achieved by continuous electron bombardment induced by operating the machine with high intensity beams with 50 and 25 ns spacing during dedicated periods at injection energy (450 GeV) and at top energy (3.5 and 4 TeV). The evolution of the Secondary Electron Yield during these periods, at different sections of the machine, can be estimated by pressure, heat load and by bunch-by-bunch RF stable phase measurements. The experimental information on the scrubbing process will be discussed and a possible “scrubbing strategy” to allow the operation with 50ns and 25ns beams after the Long Shutdown in 2013-2014 will be presented.

TUPME034	Experimental Studies for Future LHC Beams in the SPS	1652
	H. Bartosik, T. Argyropoulos, T. Bohl, S. Cettour-Cave, J.F. Esteban Müller, W. Höfle, G. Iadarola, Y. Papaphilippou, G. Rumolo, B. Salvant, F. Schmidt, E.N. Shaposhnikova, H. Timko CERN, Geneva, Switzerland A.Y. Molodozhentsev KEK, Ibaraki, Japan
	The High Luminosity LHC (HL-LHC) project requires significantly higher beam intensity than presently accessible in the LHC injector chain. The aim of the LHC injectors upgrade project (LIU) is to prepare the CERN accelerators for the future needs of the LHC. Therefore a series of machine studies with high brightness beams were performed, assessing the present performance reach and identifying remaining limitations. Of particular concern are beam loading and longitudinal instabilities at high energy, space charge for beams with 50ns bunch spacing and electron cloud effects for beams with 25ns bunch spacing. This paper provides a summary of the performed studies, that have been possible thanks to the implementation of the SPS low gamma-transition optics.

TUPME046	Performance of SPS Low Transition Energy Optics for LHC Ion Beams	1667
	F. Antoniou, G. Arduini, H. Bartosik, T. Bohl, S. Cettour Cave, K. Cornelis, D. Manglunki, Y. Papaphilippou CERN, Geneva, Switzerland
	An optics with low transition energy has been developed in the SPS for removing intensity limitations of the LHC proton beam and has become operational towards the second part of the 2012 LHC proton run. This optics was also used for filling the LHC with lead ions during the p/Pb run of the beginning of 2013. The impact of this optics in the performance of the LHC ion beam is studied here, especially with respect to collective effects, at the SPS injection energy. In particular, the potential gain of the increased beam sizes provided by this optics, with respect to losses and emittance blow up due to space-charge and Intrabeam Scattering (IBS) is evaluated. The measured lifetime is compared with the one provided by the Touschek effect and its interplay with RF noise is studied. The models are supported by measurements in the SPS and in the LHC flat bottom.

TUPWA049	Short High-Intensity Bunches for Plasma Wakefield Experiment AWAKE in the CERN SPS	1820
	H. Timko, T. Argyropoulos, H. Bartosik, T. Bohl, J.F. Esteban Müller, E.N. Shaposhnikova CERN, Geneva, Switzerland A.V. Petrenko BINP SB RAS, Novosibirsk, Russia
	Obtaining the shortest possible bunch length in combination with the smallest transverse emittances and highest bunch intensity – this is the wish list of the proton-bunch driven, plasma wakefield acceleration experiment AWAKE currently under feasibility study at CERN. A few measurement sessions were conducted to determine the achievable bunch properties and their reproducibility. To obtain a short bunch length, the bunches were rotated in longitudinal phase space using the maximum available RF voltage prior to extraction. Measurements were carried out in two optics with different transition energies. The main performance limitation is longitudinal beam instability that develops during the acceleration ramp. With lower transition energy, beam stability is improved, but the bucket area is smaller for the same voltage. Based on the results obtained, we shall discuss the choice of optics, the impact of longitudinal instabilities, the importance of reproducibility, as well as options for improving the bunch parameters.

WEXB101	Optics Optimization for Reducing Collective Effects and Raising Instability Thresholds in Lepton and Hadron Rings	2033
	Y. Papaphilippou, F. Antoniou, H. Bartosik CERN, Geneva, Switzerland
	This paper covers recent progress in the design of optics solutions to minimize collective effects such as beam instabilities, intra-beam scattering or space charge in hadron and lepton rings. The necessary steps are reviewed for designing the optics of high-intensity and high-brightness synchrotrons but also ultra-low emittance lepton storage rings, whose performance is strongly dominated by collective effects. Particular emphasis is given to proposed and existing designs illustrated by simulations and beam measurements.
	Slides WEXB101 [24.511 MB]

WEPEA014	Recent Electron Cloud Studies in the SPS	2525
	G. Iadarola, H. Bartosik, M. Driss Mensi, H. Neupert, G. Rumolo, M. Taborelli CERN, Geneva, Switzerland G. Iadarola Naples University Federico II, Science and Technology Pole, Napoli, Italy
	It is important to qualify the present status of the SPS with respect to the electron cloud before the Long Shutdown of the CERN accelerator complex, which will take place in 2013-2014. Therefore several electron cloud studies were performed during the 2012 run in order to get a full characterization of the behavior of the SPS with the LHC-type beams with 25 ns bunch spacing, which can be very sensitive to electron cloud effects. The collected information should allow to understand up to which extent this long period without beam operation - and the related interventions on the machine - will degrade the present conditioning state of the SPS, which has been achieved by “scrubbing” over several years. Several measurements with different beam conditions have been collected also on the electron cloud detectors installed in the machine. These results, in combination with detailed simulation studies, will provide the basis for defining strategies of electron cloud mitigation as required for the production of future high intensity and high brightness beams within the LHC Injectors Upgrade (LIU) project.

WEPEA053	Progress with the Upgrade of the SPS for the HL-LHC Era	2624
	B. Goddard, T. Argyropoulos, W. Bartmann, H. Bartosik, T. Bohl, F. Caspers, K. Cornelis, H. Damerau, L.N. Drøsdal, L. Ducimetière, J.F. Esteban Müller, R. Garoby, M. Gourber-Pace, W. Höfle, G. Iadarola, L.K. Jensen, V. Kain, R. Losito, M. Meddahi, A. Mereghetti, V. Mertens, Ö. Mete, E. Montesinos, Y. Papaphilippou, G. Rumolo, B. Salvant, E.N. Shaposhnikova, M. Taborelli, H. Timko, F.M. Velotti CERN, Geneva, Switzerland E. Gianfelice-Wendt Fermilab, Batavia, USA
	The demanding beam performance requirements of the HL-LHC project translate into a set of requirements and upgrade paths for the LHC injector complex. In this paper the performance requirements for the SPS and the known limitations are reviewed in the light of the 2012 operational experience. The various SPS upgrades in progress and still under consideration are described, in addition to the machine studies and simulations performed in 2012. The expected machine performance reach is estimated on the basis of the present knowledge, and the remaining decisions that still need to be made concerning upgrade options are detailed.

WEPEA056	Design and Beam Measurements of Modified Fast Extraction Schemes in the CERN PS for Installing a Dummy Septum to Mitigate Ring Irradiation	2633
	C. Hernalsteens, H. Bartosik, L.N. Drøsdal, S.S. Gilardoni, M. Giovannozzi, A. Lachaize, Y. Papaphilippou, A. Ulsroed CERN, Geneva, Switzerland
	The proposed Multi-Turn Extraction (MTE) for the CERN PS allows to reduce the overall extraction losses for high intensity beams. The required longitudinal structure of the proton beam induces unavoidable beam losses at the magnetic extraction septum. The installation of a dummy septum with an appropriate shielding has been proposed to localise losses and to shadow the magnetic septum. Such a device, located in the extraction region, imposes tight constraints on the available beam aperture. Modified extraction schemes have been proposed and in this paper they will be presented and discussed in detail together with the measured performance.

WEPEA060	Plans for the Upgrade of CERN's Heavy Ion Complex	2645
	D. Manglunki, M. E. Angoletta, H. Bartosik, A. Blas, D. Bodart, M.A. Bodendorfer, T. Bohl, J. Borburgh, E. Carlier, J.-M. Cravero, H. Damerau, L. Ducimetière, A. Findlay, R. Garoby, S.S. Gilardoni, B. Goddard, S. Hancock, E.B. Holzer, J.M. Jowett, T. Kramer, D. Kuchler, A.M. Lombardi, Y. Papaphilippou, S. Pasinelli, R. Scrivens, G. Tranquille CERN, Geneva, Switzerland
	To reach a luminosity higher than 6×10²⁷ Hz/cm² for Pb-Pb collisions, as expected by the ALICE experiment after its upgrade during the 2nd Long LHC Shutdown (LS2), several upgrades will have to be performed in the CERN accelerator complex, from the source to the LHC itself. This paper first details the present limitations and then describes the strategy for the different machines in the ion injector chain. Both filling schemes and possible hardware upgrades are discussed.

WEPEA061	The First LHC p-Pb run: Performance of the Heavy Ion Production Complex	2648
	D. Manglunki, M. E. Angoletta, H. Bartosik, G. Bellodi, A. Blas, M.A. Bodendorfer, T. Bohl, C. Carli, E. Carlier, S. Cettour Cave, K. Cornelis, H. Damerau, A. Findlay, S.S. Gilardoni, S. Hancock, J.M. Jowett, D. Kuchler, M. O'Neil, Y. Papaphilippou, S. Pasinelli, R. Scrivens, G. Tranquille, B. Vandorpe, U. Wehrle, J. Wenninger CERN, Geneva, Switzerland
	TThe first LHC proton-ion run took place in January-February 2013; it was the first extension to the collider programme, as this mode was not included in the design report. This paper presents the performance of the heavy ion and proton production complex, and details the issues encountered, in particular the creation of the same bunch pattern in both beams.

WEPME060	First Results and Analysis of the Performance of a 4 GS/s Intra-bunch Vertical Feedback System at the SPS	3070
	J.M. Cesaratto, J.E. Dusatko, J.D. Fox, J.J. Olsen, K.M. Pollock, C.H. Rivetta, O. Turgut SLAC, Menlo Park, California, USA H. Bartosik, W. Höfle, G. Kotzian, U. Wehrle CERN, Geneva, Switzerland
	Funding: Work supported by the U.S. Department of Energy under contract DE-AC02-76SF00515 and the US LHC Accelerator Research program ( LARP) We present experimental measurements taken from SPS machine development studies with an intra-bunch feedback channel. These studies use a digital signal processing system to implement general-purpose control algorithms on multiple samples across a single SPS bunch ( for ease of synchronization with the SPS RF frequency a sampling frequency of 3.2 GS/sec. is implemented). These initial studies concentrate on single-bunch motion, and study the vertical betatron motion as the feedback control is varied. The studies are focused on validating simulation models of the beam dynamics with feedback. Time and frequency domain results include excitation and damping of intra-bunch motion with positive and negative feedback. We present an overview of the challenges of intra-bunch feedback, and highlight methods to time-align the pickup and kicker signals within the closed-loop feedback channel.

THOBB102	Beam Coupling Impedance Localization Technique Validation and Measurements in the CERN Machines	3106
	N. Biancacci, G. Arduini, T. Argyropoulos, H. Bartosik, R. Calaga, K. Cornelis, S.S. Gilardoni, N. Mounet, E. Métral, Y. Papaphilippou, S. Persichelli, G. Rumolo, B. Salvant, G. Sterbini, R. Tomás, R. Wasef CERN, Geneva, Switzerland M. Migliorati, L. Palumbo URLS, Rome, Italy
	The beam coupling impedance could lead to limitations in beam brightness and quality, and therefore it needs accurate quantification and continuous monitoring in order to detect and mitigate high impedance sources. In the CERN machines, for example, kickers and collimators are expected to be the main contributors to the total imaginary part of the transverse impedance. In order to detect the other sources, a beam based measurement was developed: from the variation of betatron phase beating with intensity, it is possible to detect the locations of main impedance sources. In this work we present the application of the method with beam measurements in the CERN PS, SPS and LHC.
	Slides THOBB102 [7.224 MB]

THPWO080	Operational Performance of the LHC Proton Beams with the SPS Low Transition Energy Optics	3945
	Y. Papaphilippou, G. Arduini, T. Argyropoulos, W. Bartmann, H. Bartosik, T. Bohl, C. Bracco, S. Cettour-Cave, K. Cornelis, L.N. Drøsdal, J.F. Esteban Müller, B. Goddard, A. Guerrero, W. Höfle, V. Kain, G. Rumolo, B. Salvant, E.N. Shaposhnikova, H. Timko, D. Valuch, G. Vanbavinckhove, J. Wenninger CERN, Geneva, Switzerland E. Gianfelice-Wendt Fermilab, Batavia, USA
	An optics in the SPS with lower integer tunes (20 versus 26) was proposed and introduced in machine studies since 2010, as a measure for increasing transverse and longitudinal instability thresholds, especially at low energy, for the LHC proton beams. After two years of machine studies and careful optimisation, the new “Q20” optics became operational in September 2012 and steadily delivered beam to the LHC until the end of the run. This paper reviews the operational performance of the Q20 optics with respect to transverse and longitudinal beam characteristics in the SPS, enabling high brightness beams injected into the LHC. Aspects of longitudinal beam stability, transmission, high-energy orbit control and beam transfer are discussed.