IPAC2013 - List of Authors (Schulte, D.)

Paper	Title	Page
MOPWO024	Design of the CLIC Pre-Main Linac Collimation System	936
	R. Apsimon, A. Latina, D. Schulte, J.A. Uythoven CERN, Geneva, Switzerland J. Resta-López IFIC, Valencia, Spain
	A main beam collimation system, upstream of the main linac, is essential to protect the linac from particles in the beam halo. The proposed system consists of an energy collimation (EC) system just after the booster linac near the start of the Ring-to-Main Linac (RTML) transfer line and an EC and betatron collimation (BC) system at the end of the RTML, just before the main linac. The design requirements are presented and the cleaning efficiency of the proposed systems is analysed for different design choices.

MOPWO053	Evolution of the Tracking Code PLACET	1014
	A. Latina, Y.I. Levinsen, D. Schulte CERN, Geneva, Switzerland J. Snuverink JAI, Egham, Surrey, United Kingdom
	The tracking code PLACET simulates beam transport and orbit corrections in linear accelerators. It incorporates single- and multi-bunch effects, static and dynamic imperfections. A major restructuring of its core has resulted in an improvement in its modularity, with some immediate advantages: its tracking core, which is one of the fastest available for this kind of simulations, is now interfaced toward three different scripting languages to offer great simulation capabilities: Tcl/Tk, Octave and Python. These three languages provide access to a vast library of scientific tools, mechanisms for parallel computing, and access to Java interfaces for control systems (such as that of CTF3). Also, new functionalities have been added: parallel tracking to exploit modern multicore CPUs, the possibility to track through the interaction region in presence of external magnetic fields (detector solenoid) and higher order imperfections in magnets. PLACET is currently used to simulate the CLIC Drive Beam, the CLIC Main Beam, CTF3, FACET at SLAC, and ATF2 at KEK.

TUPME031	Considerations for a Higgs Facility Based on Laser Wakefield Acceleration	1643
	S. Hillenbrand, A.-S. Müller KIT, Karlsruhe, Germany R.W. Aßmann, S. Hillenbrand, D. Schulte CERN, Geneva, Switzerland
	Laser Wakefield Accelerators have seen tremendous progress over the last decades. It is hoped that they will allow to significantly reduce the size and cost of a future liner collider. Based on scaling laws, laser-driven plasma accelerators are investigated as drivers for smaller scale facilities capable of producing Z and Higgs bosons.

TUPME048	Imperfection Tolerances for On-line Dispersion Free Steering in the Main Linac of CLIC	1673
	J. Pfingstner, A. Latina, D. Schulte CERN, Geneva, Switzerland
	Long-term ground motion misaligns the elements of the main linac of CLIC over time. Especially the misaligned quadrupoles create dispersion and hence the beam quality is decreased gradually due to an effect called chromatic dilution. Over longer time periods, orbit feedback systems are not capable to fully recover the beam quality and have to be supplemented by dispersion correction algorithms. In this paper, such and dispersion correction algorithm is presented, which is an extended version of the well-known dispersion free steering algorithm. This extended algorithm can recover the beam quality over long time scaled without stopping the accelerator operation (on-line). Tolerances for different imperfections of the system have been identified and a strong sensitivity to the resolution of the wake field monitors of the main linac accelerating structures has been identified. This problem can be mitigated by using a local excitation scheme as will be shown in this work.

TUPME049	Status of the Exploration of an Alternative CLIC First Energy Stage Based on Klystrons	1676
	D. Schulte, A. Grudiev, P. Lebrun, G. McMonagle, I. Syratchev, W. Wuensch CERN, Geneva, Switzerland
	The Compact Linear Collider is based on a two-beam scheme to accelerate the main, colliding beams. This scheme allows to reach very high centre-of-mass energies. At low collision energies the main beams could be accelerated by powering the accelerating structures with X-band instead of a second beam. We explore this option and indicate the parameters and conceptual design.

TUPME050	Performance Comparison of Different System Identification Algorithms for FACET and ATF2	1679
	J. Pfingstner, A. Latina, D. Schulte CERN, Geneva, Switzerland
	Good system knowledge is an essential ingredient for the operation of modern accelerator facilities. For example, beam-based alignment algorithms and orbit feedbacks rely strongly on a precise measurement of the orbit response matrix. The quality of the measurement of this matrix can be improved over time by statistically combining the effects of small system excitations with the help of system identification algorithms. These small excitations can be applied in a parasitic mode without stopping the accelerator operation (on-line). In this work, different system identification algorithms are used in simulation studies for the response matrix measurement at ATF2. The results for ATF2 are finally compared with the results for FACET, latter originating from an earlier work.

TUPME051	CLIC Final Focus System Alignment and Magnet Tolerances	1682
	J. Snuverink, J. Barranco, H. Garcia, Y.I. Levinsen, D. Schulte, R. Tomás CERN, Geneva, Switzerland
	The design requirements for the magnets in the Compact Linear Collider (CLIC) Final Focus System (FFS) are very stringent. In this paper the sensitivity for the misalignment and the magnetic imperfections for the different magnets in the FFS and the crab cavity are presented. Possible mitigation methods are discussed.

TUPWA045	Longitudinal Space Charge Effects in the CLIC Drive Beam	1811
	R.L. Lillestøl, S. Döbert, A. Latina, D. Schulte CERN, Geneva, Switzerland E. Adli, K.N. Sjobak University of Oslo, Oslo, Norway
	The CLIC main beam is accelerated by rf power generated from a high-intensity, low-energy electron drive beam. The accelerating fields are produced in Power Extraction and Transfer Structures, and are strongly dependent on the drive beam bunch distribution, as well as other parameters. We investigate how longitudinal space charge affects the bunch distribution and the corresponding power production, and discuss how the bunch length evolution can affect the main beam. We also describe the development of a Particle-in-Cell space charge solver which was used for the study.

Paper

Title

Page

Design of the CLIC Pre-Main Linac Collimation System

936

R. Apsimon, A. Latina, D. Schulte, J.A. Uythoven
CERN, Geneva, Switzerland
J. Resta-López
IFIC, Valencia, Spain

A main beam collimation system, upstream of the main linac, is essential to protect the linac from particles in the beam halo. The proposed system consists of an energy collimation (EC) system just after the booster linac near the start of the Ring-to-Main Linac (RTML) transfer line and an EC and betatron collimation (BC) system at the end of the RTML, just before the main linac. The design requirements are presented and the cleaning efficiency of the proposed systems is analysed for different design choices.

MOPWO053

Evolution of the Tracking Code PLACET

1014

A. Latina, Y.I. Levinsen, D. Schulte
CERN, Geneva, Switzerland
J. Snuverink
JAI, Egham, Surrey, United Kingdom

The tracking code PLACET simulates beam transport and orbit corrections in linear accelerators. It incorporates single- and multi-bunch effects, static and dynamic imperfections. A major restructuring of its core has resulted in an improvement in its modularity, with some immediate advantages: its tracking core, which is one of the fastest available for this kind of simulations, is now interfaced toward three different scripting languages to offer great simulation capabilities: Tcl/Tk, Octave and Python. These three languages provide access to a vast library of scientific tools, mechanisms for parallel computing, and access to Java interfaces for control systems (such as that of CTF3). Also, new functionalities have been added: parallel tracking to exploit modern multicore CPUs, the possibility to track through the interaction region in presence of external magnetic fields (detector solenoid) and higher order imperfections in magnets. PLACET is currently used to simulate the CLIC Drive Beam, the CLIC Main Beam, CTF3, FACET at SLAC, and ATF2 at KEK.

TUPME031

Considerations for a Higgs Facility Based on Laser Wakefield Acceleration

1643

S. Hillenbrand, A.-S. Müller
KIT, Karlsruhe, Germany
R.W. Aßmann, S. Hillenbrand, D. Schulte
CERN, Geneva, Switzerland

Laser Wakefield Accelerators have seen tremendous progress over the last decades. It is hoped that they will allow to significantly reduce the size and cost of a future liner collider. Based on scaling laws, laser-driven plasma accelerators are investigated as drivers for smaller scale facilities capable of producing Z and Higgs bosons.

TUPME048

Imperfection Tolerances for On-line Dispersion Free Steering in the Main Linac of CLIC

1673

J. Pfingstner, A. Latina, D. Schulte
CERN, Geneva, Switzerland

Long-term ground motion misaligns the elements of the main linac of CLIC over time. Especially the misaligned quadrupoles create dispersion and hence the beam quality is decreased gradually due to an effect called chromatic dilution. Over longer time periods, orbit feedback systems are not capable to fully recover the beam quality and have to be supplemented by dispersion correction algorithms. In this paper, such and dispersion correction algorithm is presented, which is an extended version of the well-known dispersion free steering algorithm. This extended algorithm can recover the beam quality over long time scaled without stopping the accelerator operation (on-line). Tolerances for different imperfections of the system have been identified and a strong sensitivity to the resolution of the wake field monitors of the main linac accelerating structures has been identified. This problem can be mitigated by using a local excitation scheme as will be shown in this work.

TUPME049

Status of the Exploration of an Alternative CLIC First Energy Stage Based on Klystrons

1676

D. Schulte, A. Grudiev, P. Lebrun, G. McMonagle, I. Syratchev, W. Wuensch
CERN, Geneva, Switzerland

The Compact Linear Collider is based on a two-beam scheme to accelerate the main, colliding beams. This scheme allows to reach very high centre-of-mass energies. At low collision energies the main beams could be accelerated by powering the accelerating structures with X-band instead of a second beam. We explore this option and indicate the parameters and conceptual design.

TUPME050

Performance Comparison of Different System Identification Algorithms for FACET and ATF2

1679

J. Pfingstner, A. Latina, D. Schulte
CERN, Geneva, Switzerland

Good system knowledge is an essential ingredient for the operation of modern accelerator facilities. For example, beam-based alignment algorithms and orbit feedbacks rely strongly on a precise measurement of the orbit response matrix. The quality of the measurement of this matrix can be improved over time by statistically combining the effects of small system excitations with the help of system identification algorithms. These small excitations can be applied in a parasitic mode without stopping the accelerator operation (on-line). In this work, different system identification algorithms are used in simulation studies for the response matrix measurement at ATF2. The results for ATF2 are finally compared with the results for FACET, latter originating from an earlier work.

TUPME051

CLIC Final Focus System Alignment and Magnet Tolerances

1682

J. Snuverink, J. Barranco, H. Garcia, Y.I. Levinsen, D. Schulte, R. Tomás
CERN, Geneva, Switzerland

The design requirements for the magnets in the Compact Linear Collider (CLIC) Final Focus System (FFS) are very stringent. In this paper the sensitivity for the misalignment and the magnetic imperfections for the different magnets in the FFS and the crab cavity are presented. Possible mitigation methods are discussed.

TUPWA045

Longitudinal Space Charge Effects in the CLIC Drive Beam

1811

R.L. Lillestøl, S. Döbert, A. Latina, D. Schulte
CERN, Geneva, Switzerland
E. Adli, K.N. Sjobak
University of Oslo, Oslo, Norway

The CLIC main beam is accelerated by rf power generated from a high-intensity, low-energy electron drive beam. The accelerating fields are produced in Power Extraction and Transfer Structures, and are strongly dependent on the drive beam bunch distribution, as well as other parameters. We investigate how longitudinal space charge affects the bunch distribution and the corresponding power production, and discuss how the bunch length evolution can affect the main beam. We also describe the development of a Particle-in-Cell space charge solver which was used for the study.