IPAC2012 - List of Authors (Schulte, D.)

Paper	Title	Page
MOPPC073	Improvements in the PLACET Tracking Code	301
	A. Latina, E. Adli, D. Schulte, J. Snuverink CERN, Geneva, Switzerland B. Dalena CEA/IRFU, Gif-sur-Yvette, France
	The tracking code PLACET simulates beam transport and orbit corrections in linear accelerators. It incorporates single- and multi-bunch effects, static and dynamic imperfections. It has an interface based on both Tcl/Tk and Octave to provide maximum flexibility and easy programming of complex scenarios. Recently, new functionality has been added to expand its simulation and tuning capabilities, such as: tools to perform beam-based alignment of non-linear optical systems, possibility to track through the interaction region in presence of external magnetic fields (detector solenoid), higher order imperfections in magnets, better tools for integrated feedback loops. Moreover, self contained frameworks have been created to ease the simulation of CLIC Drive Beam, CLIC Main Beam, and other existing electron machines such as CTF3 and FACET.

TUPPR024	CLIC Recombination Scheme for the Low Energy Operation Mode	1864
	A. Gerbershagen, D. Schulte CERN, Geneva, Switzerland P. Burrows Oxford University, Physics Department, Oxford, Oxon, United Kingdom
	The CLIC recombination scheme is a concept of multiplication of the drive beam frequency in order to generate a 12 GHz RF wave for the main beam acceleration. CLIC is designed to be operated in nominal and in low energy modes. The low energy operation modes require the train length to be increased by different factors in order to maintain the same level of luminosity. Also the number of initial trains that are merged to form each final train is changed. The combination scheme must be able to accommodate and recombine both long and short trains for nominal and low energy CLIC operation modes. The recombination hence becomes a non-trivial process and makes the correction of the errors in the drive beam more challenging. The present paper describes in detail the recombination process and its consequences.

TUPPR028	Recent Improvements in the Orbit Feedback and Ground Motion Mitigation Techniques for CLIC	1876
	J. Snuverink, J. Pfingstner, D. Schulte CERN, Geneva, Switzerland
	The Compact Linear Collider (CLIC) accelerator has strong stability requirements on the position of the beam. In particular, the beam position will be sensitive to ground motion. A number of mitigation techniques have been proposed - quadrupole stabilization and positioning, final doublet stabilization as well as beam based orbit and interaction point (IP) feedback. Integrated studies of the impact of ground motion on the CLIC Main Linac (ML) and Beam Delivery System (BDS) that model the latest hardware designs have been performed. Furthermore, additional imperfections have been introduced and the robustness of this system is discussed in detail. The possibility of using ground motion measurements as an alternative to the quadrupole stabilization is investigated.

TUPPR029	Performance of Linear Collider Beam-Based Alignment Algorithms at FACET	1879
	A. Latina, J. Pfingstner, D. Schulte CERN, Geneva, Switzerland E. Adli University of Oslo, Oslo, Norway
	The performance of future linear colliders will depend critically on beam-based alignment (BBA) and feedback systems, which will play a crucial role both in the linear and in the non-linear systems of such machines, e.g., the linac and the final-focus. Due to its characteristics, FACET is an ideal test-bench for BBA algorithms and linear collider beam-dynamics in general. We present the results of extensive computer simulations and their experimental verification.

TUPPR034	Beam-based Alignment in CTF3 Test Beam Line	1894
	G. Sterbini, S. Döbert, R.L. Lillestøl, E. Marín, D. Schulte CERN, Geneva, Switzerland E. Adli University of Oslo, Oslo, Norway
	The CLIC linear collider is based on the two beams acceleration scheme. During acceleration, the drive beam suffers a large increase in its energy spread. In order to efficiently transport such a beam, beam-based alignment techniques together with tight pre-alignment tolerances are crucial. A beam-based steering campaign has been conducted at the Test Beam Line of the CLIC Test Facility to evaluate the performance of several algorithms. In the following we present and discuss the obtained results.

TUPPR035	A Comparative Study for the CLIC Drive Beam Decelerator Optics	1897
	G. Sterbini, D. Schulte CERN, Geneva, Switzerland E. Adli University of Oslo, Oslo, Norway
	The baseline for the CLIC drive beam decelerators optics consists of a 2-m-long FODO cell. This solution was adopted to have strong focusing in order to mitigate the effect of the PETS wakefields and to minimize the drive beam envelope. Taking into account the most recent PETS design, we compare the performance of the baseline FODO cell with a proposal that consider twice longer FODO cell. Despite of the expected cost in term of performance, the reduction of the complexity of the system due to the halving of the number of quadrupoles can be beneficial for the overall optimization of the decelerator design.

TUPPR039	Beam Dynamics Studies for the CLIC Main Linac	1903
	I. Nesmiyan, R.M. Jones UMAN, Manchester, United Kingdom A. Latina, D. Schulte CERN, Geneva, Switzerland
	Implications of the long-range wakefield on beam quality are investigated through a detailed beam dynamics study. Injection offsets are considered and the resulting emittance dilution recorded, including systematic and random sources of error. These simulations have been conducted for damped and detuned structures (DDS) and for waveguide damped structures–both for the CLIC collider.

TUPPR060	Detection of Ground Motion Effects on the Beam Trajectory at ATF2	1954
	Y. Renier, J. Pfingstner, D. Schulte, R. Tomás CERN, Geneva, Switzerland
	The ATF2 experiment is currently demonstrating the feasibility of the beam delivery system for the future linear collider. The tunning is very critical to obtain the nanometer vertical beam size at the interaction point and in the case of CLIC, ground motion effects on the beam must be corrected. In this respect, as a proof of principle of a ground motion feed forward, the ground motion effects on the beam trajectory are extracted from the beam position monitor readings.

WEPPP066	Performance Simulations of a Phase Stabilization System Prototype for CTF3	2858
	A. Gerbershagen, T. Persson, D. Schulte, P. Skowroński CERN, Geneva, Switzerland P. Burrows, G.B. Christian Oxford University, Physics Department, Oxford, Oxon, United Kingdom A. Gerbershagen, C. Perry JAI, Oxford, United Kingdom E. Ikarios National Technical University of Athens, Athens, Greece
	The CLIC drive beam provides RF power for acceleration of the main beam, and hence the drive beam’s longitudinal phase tolerances are very tight. A feedforward chicane consisting of four electromagnetic kickers is proposed as a correction system for the phase errors, which should allow loosening of the tolerances. A prototype of such a chicane system, developed by CERN, INFN and the University of Oxford, is planned to be installed at CFT3 in 2012. The present paper summarizes the parameters of the planned phase correction system and presents simulations, which are used to make predictions of the performance of such a feedforward system at CTF3.

TUPPC086	Conceptual Design of the CLIC damping rings	1368
	Y. Papaphilippou, F. Antoniou, M.J. Barnes, S. Calatroni, P. Chiggiato, R. Corsini, A. Grudiev, J. Holma, T. Lefèvre, M. Martini, M. Modena, N. Mounet, A. Perin, Y. Renier, G. Rumolo, S. Russenschuck, H. Schmickler, D. Schoerling, D. Schulte, M. Taborelli, G. Vandoni, F. Zimmermann CERN, Geneva, Switzerland C. Belver-Aguilar, A. Faus-Golfe IFIC, Valencia, Spain A. Bernhard KIT, Karlsruhe, Germany M.J. Boland ASCo, Clayton, Victoria, Australia A.V. Bragin, E.B. Levichev, S.V. Sinyatkin, P. Vobly, K. Zolotarev BINP SB RAS, Novosibirsk, Russia M. Korostelev Cockcroft Institute, Warrington, Cheshire, United Kingdom E. Koukovini EPFL, Lausanne, Switzerland M.A. Palmer CLASSE, Ithaca, New York, USA M.T.F. Pivi, S.R. Smith SLAC, Menlo Park, California, USA R.P. Rassool, K.P. Wootton The University of Melbourne, Melbourne, Australia L. Rinolfi JUAS, Archamps, France A. Vivoli Fermilab, Batavia, USA
	The CLIC damping rings are designed to produce unprecedentedly low-emittances of 500 nm and 5 nm normalized at 2.86 GeV, in all beam dimensions with high bunch charge, necessary for the performance of the collider. The large beam brightness triggers a number of beam dynamics and technical challenges. Ring parameters such as energy, circumference, lattice, momentum compaction, bending and super-conducting wiggler fields are carefully chosen in order to provide the target emittances under the influence of intrabeam scattering but also reduce the impact of collective effects such as space-charge and coherent synchrotron radiation. Mitigation techniques for two stream instabilities have been identified and tested. The low vertical emittance is achieved by modern orbit and coupling correction techniques. Design considerations and plans for technical system, such as damping wigglers, transfer systems, vacuum, RF cavities, instrumentation and feedback are finally reviewed.

WEPPR066	Effects of the External Wakefield from the CLIC PETS	3078
	A. Latina, D. Schulte CERN, Geneva, Switzerland J. Gao, Y. Wang IHEP, Beijing, People's Republic of China
	The CLIC main linac accelerating structures will be powered by the Power Extraction and Transfer Structure (PETS) located in the drive beam decelerators. Misalignments of the PETS will excite dipolar modes in the couplers of the main linac structures that will kick the beam leading to beam quality degradation. In this paper, the impact of such dipolar kicks is studied, and tolerances, based on analytical estimations, are found both in the single- and the multi-bunch regimes. Numerical simulation obtained using the tracking code PLACET are shown to confirm the analytical estimates.

WEPPR067	Study of Fundamental Mode Multipolar Kicks in Double- and Single-feed Power Couplers for the CLIC Main Linac Accelerating Structure	3081
	A. Latina, A. Grudiev, D. Schulte CERN, Geneva, Switzerland
	Multipolar kicks from the fundamental mode have been calculated in the CLIC baseline accelerating structure with double–feed input and output power couplers. The influence of such multipolar kicks on the main linac beam dynamics has been investigated. Furthermore, an alternative design of the couplers with single-feed has been studied and compared with the double-feed. Such an alternative would significantly simplify the waveguide system of the main linac but potentially introduce an harmful dipolar kick from the fundamental mode. The geometry of the coupler has been optimized in order to minimize such a dipolar kick and keep it below threshold levels determined with beam dynamics simulations. Influence of the higher order multipoles has been investigated as well and acceptable levels have been determined.

WEPPR076	Positron Options for the Linac-ring LHeC	3108
	F. Zimmermann, O.S. Brüning, Y. Papaphilippou, D. Schulte, P. Sievers CERN, Geneva, Switzerland H.-H. Braun Paul Scherrer Institut, Villigen, Switzerland E.V. Bulyak NSC/KIPT, Kharkov, Ukraine M. Klein The University of Liverpool, Liverpool, United Kingdom L. Rinolfi JUAS, Archamps, France A. Variola, Z.F. Zomer LAL, Orsay, France V. Yakimenko BNL, Upton, Long Island, New York, USA
	The full physics program of a future Large Hadron electron Collider (LHeC) requires both pe⁺ and pe- collisions. For a pulsed 140-GeV or an ERL-based 60-GeV Linac-Ring LHeC this implies a challenging rate of, respectively, about 1.8·10¹⁵ or 4.4·10¹⁶ e+/s at the collision point, which is about 300 or 7000 times the past SLC rate. We consider providing this e⁺ rate through a combination of measures: (1) Reducing the required production rate from the e⁺ target through colliding e⁺ (and the LHC protons) several times before deceleration, by reusing the e⁺ over several acceleration/deceleration cycles, and by cooling them, e.g., with a compact tri-ring scheme or a conventional damping ring in the SPS tunnel. (2) Using an advanced target, e.g., W-granules, rotating wheel, sliced-rod converter, or liquid metal jet, for converting gamma rays to e+. (3) Selecting the most powerful of several proposed gamma sources, namely Compton ERL, Compton storage ring, coherent pair production in a strong laser, or high-field undulator radiation from the high-energy lepton beam. We describe the various concepts, present example parameters, estimate the electrical power required, and mention open questions.

Paper

Title

Page

Improvements in the PLACET Tracking Code

301

A. Latina, E. Adli, D. Schulte, J. Snuverink
CERN, Geneva, Switzerland
B. Dalena
CEA/IRFU, Gif-sur-Yvette, France

The tracking code PLACET simulates beam transport and orbit corrections in linear accelerators. It incorporates single- and multi-bunch effects, static and dynamic imperfections. It has an interface based on both Tcl/Tk and Octave to provide maximum flexibility and easy programming of complex scenarios. Recently, new functionality has been added to expand its simulation and tuning capabilities, such as: tools to perform beam-based alignment of non-linear optical systems, possibility to track through the interaction region in presence of external magnetic fields (detector solenoid), higher order imperfections in magnets, better tools for integrated feedback loops. Moreover, self contained frameworks have been created to ease the simulation of CLIC Drive Beam, CLIC Main Beam, and other existing electron machines such as CTF3 and FACET.

TUPPR024

CLIC Recombination Scheme for the Low Energy Operation Mode

1864

A. Gerbershagen, D. Schulte
CERN, Geneva, Switzerland
P. Burrows
Oxford University, Physics Department, Oxford, Oxon, United Kingdom

The CLIC recombination scheme is a concept of multiplication of the drive beam frequency in order to generate a 12 GHz RF wave for the main beam acceleration. CLIC is designed to be operated in nominal and in low energy modes. The low energy operation modes require the train length to be increased by different factors in order to maintain the same level of luminosity. Also the number of initial trains that are merged to form each final train is changed. The combination scheme must be able to accommodate and recombine both long and short trains for nominal and low energy CLIC operation modes. The recombination hence becomes a non-trivial process and makes the correction of the errors in the drive beam more challenging. The present paper describes in detail the recombination process and its consequences.

TUPPR028

Recent Improvements in the Orbit Feedback and Ground Motion Mitigation Techniques for CLIC

1876

J. Snuverink, J. Pfingstner, D. Schulte
CERN, Geneva, Switzerland

The Compact Linear Collider (CLIC) accelerator has strong stability requirements on the position of the beam. In particular, the beam position will be sensitive to ground motion. A number of mitigation techniques have been proposed - quadrupole stabilization and positioning, final doublet stabilization as well as beam based orbit and interaction point (IP) feedback. Integrated studies of the impact of ground motion on the CLIC Main Linac (ML) and Beam Delivery System (BDS) that model the latest hardware designs have been performed. Furthermore, additional imperfections have been introduced and the robustness of this system is discussed in detail. The possibility of using ground motion measurements as an alternative to the quadrupole stabilization is investigated.

TUPPR029

Performance of Linear Collider Beam-Based Alignment Algorithms at FACET

1879

A. Latina, J. Pfingstner, D. Schulte
CERN, Geneva, Switzerland
E. Adli
University of Oslo, Oslo, Norway

The performance of future linear colliders will depend critically on beam-based alignment (BBA) and feedback systems, which will play a crucial role both in the linear and in the non-linear systems of such machines, e.g., the linac and the final-focus. Due to its characteristics, FACET is an ideal test-bench for BBA algorithms and linear collider beam-dynamics in general. We present the results of extensive computer simulations and their experimental verification.

TUPPR034

Beam-based Alignment in CTF3 Test Beam Line

1894

G. Sterbini, S. Döbert, R.L. Lillestøl, E. Marín, D. Schulte
CERN, Geneva, Switzerland
E. Adli
University of Oslo, Oslo, Norway

The CLIC linear collider is based on the two beams acceleration scheme. During acceleration, the drive beam suffers a large increase in its energy spread. In order to efficiently transport such a beam, beam-based alignment techniques together with tight pre-alignment tolerances are crucial. A beam-based steering campaign has been conducted at the Test Beam Line of the CLIC Test Facility to evaluate the performance of several algorithms. In the following we present and discuss the obtained results.

TUPPR035

A Comparative Study for the CLIC Drive Beam Decelerator Optics

1897

G. Sterbini, D. Schulte
CERN, Geneva, Switzerland
E. Adli
University of Oslo, Oslo, Norway

The baseline for the CLIC drive beam decelerators optics consists of a 2-m-long FODO cell. This solution was adopted to have strong focusing in order to mitigate the effect of the PETS wakefields and to minimize the drive beam envelope. Taking into account the most recent PETS design, we compare the performance of the baseline FODO cell with a proposal that consider twice longer FODO cell. Despite of the expected cost in term of performance, the reduction of the complexity of the system due to the halving of the number of quadrupoles can be beneficial for the overall optimization of the decelerator design.

TUPPR039

Beam Dynamics Studies for the CLIC Main Linac

1903

I. Nesmiyan, R.M. Jones
UMAN, Manchester, United Kingdom
A. Latina, D. Schulte
CERN, Geneva, Switzerland

Implications of the long-range wakefield on beam quality are investigated through a detailed beam dynamics study. Injection offsets are considered and the resulting emittance dilution recorded, including systematic and random sources of error. These simulations have been conducted for damped and detuned structures (DDS) and for waveguide damped structures–both for the CLIC collider.

TUPPR060

Detection of Ground Motion Effects on the Beam Trajectory at ATF2

1954

Y. Renier, J. Pfingstner, D. Schulte, R. Tomás
CERN, Geneva, Switzerland

The ATF2 experiment is currently demonstrating the feasibility of the beam delivery system for the future linear collider. The tunning is very critical to obtain the nanometer vertical beam size at the interaction point and in the case of CLIC, ground motion effects on the beam must be corrected. In this respect, as a proof of principle of a ground motion feed forward, the ground motion effects on the beam trajectory are extracted from the beam position monitor readings.

WEPPP066

Performance Simulations of a Phase Stabilization System Prototype for CTF3

2858

A. Gerbershagen, T. Persson, D. Schulte, P. Skowroński
CERN, Geneva, Switzerland
P. Burrows, G.B. Christian
Oxford University, Physics Department, Oxford, Oxon, United Kingdom
A. Gerbershagen, C. Perry
JAI, Oxford, United Kingdom
E. Ikarios
National Technical University of Athens, Athens, Greece

The CLIC drive beam provides RF power for acceleration of the main beam, and hence the drive beam’s longitudinal phase tolerances are very tight. A feedforward chicane consisting of four electromagnetic kickers is proposed as a correction system for the phase errors, which should allow loosening of the tolerances. A prototype of such a chicane system, developed by CERN, INFN and the University of Oxford, is planned to be installed at CFT3 in 2012. The present paper summarizes the parameters of the planned phase correction system and presents simulations, which are used to make predictions of the performance of such a feedforward system at CTF3.

TUPPC086

Conceptual Design of the CLIC damping rings

1368

Y. Papaphilippou, F. Antoniou, M.J. Barnes, S. Calatroni, P. Chiggiato, R. Corsini, A. Grudiev, J. Holma, T. Lefèvre, M. Martini, M. Modena, N. Mounet, A. Perin, Y. Renier, G. Rumolo, S. Russenschuck, H. Schmickler, D. Schoerling, D. Schulte, M. Taborelli, G. Vandoni, F. Zimmermann
CERN, Geneva, Switzerland
C. Belver-Aguilar, A. Faus-Golfe
IFIC, Valencia, Spain
A. Bernhard
KIT, Karlsruhe, Germany
M.J. Boland
ASCo, Clayton, Victoria, Australia
A.V. Bragin, E.B. Levichev, S.V. Sinyatkin, P. Vobly, K. Zolotarev
BINP SB RAS, Novosibirsk, Russia
M. Korostelev
Cockcroft Institute, Warrington, Cheshire, United Kingdom
E. Koukovini
EPFL, Lausanne, Switzerland
M.A. Palmer
CLASSE, Ithaca, New York, USA
M.T.F. Pivi, S.R. Smith
SLAC, Menlo Park, California, USA
R.P. Rassool, K.P. Wootton
The University of Melbourne, Melbourne, Australia
L. Rinolfi
JUAS, Archamps, France
A. Vivoli
Fermilab, Batavia, USA

The CLIC damping rings are designed to produce unprecedentedly low-emittances of 500 nm and 5 nm normalized at 2.86 GeV, in all beam dimensions with high bunch charge, necessary for the performance of the collider. The large beam brightness triggers a number of beam dynamics and technical challenges. Ring parameters such as energy, circumference, lattice, momentum compaction, bending and super-conducting wiggler fields are carefully chosen in order to provide the target emittances under the influence of intrabeam scattering but also reduce the impact of collective effects such as space-charge and coherent synchrotron radiation. Mitigation techniques for two stream instabilities have been identified and tested. The low vertical emittance is achieved by modern orbit and coupling correction techniques. Design considerations and plans for technical system, such as damping wigglers, transfer systems, vacuum, RF cavities, instrumentation and feedback are finally reviewed.

WEPPR066

Effects of the External Wakefield from the CLIC PETS

3078

A. Latina, D. Schulte
CERN, Geneva, Switzerland
J. Gao, Y. Wang
IHEP, Beijing, People's Republic of China

The CLIC main linac accelerating structures will be powered by the Power Extraction and Transfer Structure (PETS) located in the drive beam decelerators. Misalignments of the PETS will excite dipolar modes in the couplers of the main linac structures that will kick the beam leading to beam quality degradation. In this paper, the impact of such dipolar kicks is studied, and tolerances, based on analytical estimations, are found both in the single- and the multi-bunch regimes. Numerical simulation obtained using the tracking code PLACET are shown to confirm the analytical estimates.

WEPPR067

Study of Fundamental Mode Multipolar Kicks in Double- and Single-feed Power Couplers for the CLIC Main Linac Accelerating Structure

3081

A. Latina, A. Grudiev, D. Schulte
CERN, Geneva, Switzerland

Multipolar kicks from the fundamental mode have been calculated in the CLIC baseline accelerating structure with double–feed input and output power couplers. The influence of such multipolar kicks on the main linac beam dynamics has been investigated. Furthermore, an alternative design of the couplers with single-feed has been studied and compared with the double-feed. Such an alternative would significantly simplify the waveguide system of the main linac but potentially introduce an harmful dipolar kick from the fundamental mode. The geometry of the coupler has been optimized in order to minimize such a dipolar kick and keep it below threshold levels determined with beam dynamics simulations. Influence of the higher order multipoles has been investigated as well and acceptable levels have been determined.

WEPPR076

Positron Options for the Linac-ring LHeC

3108

F. Zimmermann, O.S. Brüning, Y. Papaphilippou, D. Schulte, P. Sievers
CERN, Geneva, Switzerland
H.-H. Braun
Paul Scherrer Institut, Villigen, Switzerland
E.V. Bulyak
NSC/KIPT, Kharkov, Ukraine
M. Klein
The University of Liverpool, Liverpool, United Kingdom
L. Rinolfi
JUAS, Archamps, France
A. Variola, Z.F. Zomer
LAL, Orsay, France
V. Yakimenko
BNL, Upton, Long Island, New York, USA

The full physics program of a future Large Hadron electron Collider (LHeC) requires both pe⁺ and pe- collisions. For a pulsed 140-GeV or an ERL-based 60-GeV Linac-Ring LHeC this implies a challenging rate of, respectively, about 1.8·10¹⁵ or 4.4·10¹⁶ e+/s at the collision point, which is about 300 or 7000 times the past SLC rate. We consider providing this e⁺ rate through a combination of measures: (1) Reducing the required production rate from the e⁺ target through colliding e⁺ (and the LHC protons) several times before deceleration, by reusing the e⁺ over several acceleration/deceleration cycles, and by cooling them, e.g., with a compact tri-ring scheme or a conventional damping ring in the SPS tunnel. (2) Using an advanced target, e.g., W-granules, rotating wheel, sliced-rod converter, or liquid metal jet, for converting gamma rays to e+. (3) Selecting the most powerful of several proposed gamma sources, namely Compton ERL, Compton storage ring, coherent pair production in a strong laser, or high-field undulator radiation from the high-energy lepton beam. We describe the various concepts, present example parameters, estimate the electrical power required, and mention open questions.