ICAP2012 - List of Keywords (emittance)

Paper	Title	Other Keywords	Page
MOACC3	Tracking of a PETRA III Positron Bunch with a Pre-Computed Wake Matrix due to Electron Clouds	simulation, electron, positron, wakefield	31
	A. Markoviḱ, U. van Rienen Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany
	Funding: Work supported by DFG under contract number RI 814/20-2. At the synchrotron radiation facility at DESY transversal tune spectra have been observed which are characteristic for an interaction of the positron beam with possible electron clouds in the ring. The filling patterns at which this incoherent tune shifts happen are favourable to the growth of the electron density, i.e. long bunch trains with short intra-bunch distances or filling with short trains but also short distances between the trains. Eventually the vertical emittance growth with the originally designed equidistant filling (with 8 or 16 ns bunch spacing) has been avoided by fillings with shorter trains and longer gaps between the trains by still achieving the designed beam current of 100 mA. In this paper we examine the positron bunch stability of PETRA III for certain e-cloud densities and bunch parameters. A PIC simulation of the interaction of the bunch with an e-cloud yields the wake kick on the tail particles for an offset in the transverse centroid position of the head parts. With such a pre-computed wake matrix, we investigate the stability of a single bunch by tracking it through the linear optics of the ring while at each turn applying the kick from the e-cloud.
	Slides MOACC3 [5.237 MB]

MOSCC2	Simulation of Space Effects During Multiturn Injection into the GSI SIS18 Synchrotron	injection, simulation, space-charge, septum	37
	S. Appel GSI, Darmstadt, Germany O. Boine-Frankenheim TEMF, TU Darmstadt, Darmstadt, Germany
	The optimization of the Multiturn Injection (MTI) from the UNILAC into the SIS18 is crucial in order to reach the FAIR beam intensities required for heavy ions. In order to achieve the design intensities, the efficiency of the multiturn injection from the UNILAC has to be optimized for high beam currents. We developed a simulation model for the MTI including the closed orbit bump, lattice errors, the parameters of the injected UNILAC beam, the position of the septum and other aperture limiting components, and finally the space charge force and other high-intensity effects. The model is also used to estimate the required proton and heavy-ion beam emittances from the UNILAC and from the projected p-linac. For the accurate prediction of the MTI efficiency a careful validation of the simulation model is necessary. We will present first results of the comparison between experiments and simulation for low and high uranium beam currents.
	Slides MOSCC2 [2.511 MB]

TUAAI2	A Massively Parallel General Purpose Multi-objective Optimization Framework, Applied to Beam Dynamic Studies	simulation, status, controls, solenoid	62
	Y. Ineichen, A. Adelmann PSI, Villigen, Switzerland P. Arbenz ETH, Zurich, Switzerland C. Bekas, A. Curioni IBM Research - Zurich, Rueschlikon, Switzerland
	Particle accelerators are invaluable tools for research in basic and applied sciences. The successful design, commissioning, and operation of accelerator facilities is non trivial. We implemented a framework for general simulation-based multi-optimization methods automating the investigation of optimal sets of machine parameters. In order to solve the emerging, huge problems we propose a massively-parallel master/slave approach. We employ the framework to identify optimal parameters of existing and new accelerators at PSI.
	Slides TUAAI2 [0.694 MB]

TUABC2	Global Optimization of the ANKA Lattice Using Multiobjective Genetic Algorithms (MOGA)	optics, quadrupole, lattice, storage-ring	72
	M. Streichert, N. Hiller, E. Huttel, V. Judin, B. Kehrer, M. Klein, S. Marsching, C.A.J. Meuter, A.-S. Müller, M.J. Nasse, M. Schuh, N.J. Smale KIT, Karlsruhe, Germany
	Funding: This work has been supported by the Initiative and Networking Fund of the Helmholtz Association under contract number VH-NG-320. The optimization of a storage ring lattice is a multiobjective problem, since the parameter space of possible solutions can be very large and a high number of constraints have to be taken into account during the optimization process. In this paper we used Genetic Algorithms (GA) and MultiObjective Genetic Algorithms (MOGA), which can solve such problems very efficiently and rapidly, to find the optimized settings for the ANKA storage ring lattice.

TUSBC2	Low Noise Particle-in-Cell Simulations of Laser Plasma Accelerator 10 GeV Stages	plasma, simulation, laser, electron	78
	E. Cormier-Michel, D.L. Bruhwiler, J.R. Cary, B.M. Cowan, E.J. Hallman Tech-X, Boulder, Colorado, USA E. Esarey, C.G.R. Geddes, W. Leemans, C.B. Schroeder, J.-L. Vay LBNL, Berkeley, California, USA
	Funding: Work supported by DOE/HEP, under grants DE-SC0004441 and DE-FC02-07ER41499, including use of NERSC under DE-AC02-05CH11231. Because of their ultra-high accelerating gradient, laser plasma based accelerators (LPA) are contemplated for the next generation of high-energy colliders and light sources. The upcoming BELLA project will explore acceleration of electron bunches to 10 GeV in a 1 meter long plasma, where a wakefield is driven by a PW-class laser. Particle-in-cell (PIC) simulations are used to design the upcoming experiments where boosted frame simulations are used to model the full scale stages. As criteria on energy spread and beam emittance become more stringent, PIC simulations become more challenging as high frequency noise artificially increases those quantities. We show that calculating the beam self-fields using a static Poisson solve in the beam frame dramatically reduces particle noise, allowing for more accurate simulation of the beam evolution. In particular, this method gets correct cancellation of the transverse self-electric and magnetic fields of the beam, eliminating artificial self-forces, which is usually not true when using the standard PIC algorithm based on the staggered (“Yee”) electromagnetic field solver.
	Slides TUSBC2 [5.989 MB]

WEP02	Numerical Studies on the Influence of Fill Patterns on Ion Clouds	ion, electron, simulation, vacuum	146
	A. Meseck HZB, Berlin, Germany G. Pöplau, U. van Rienen Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany
	Funding: supported by BMBF under contract no. 05K10HRC Energy Recovery Linacs (ERLs) are the most promising candidates for next-generation light sources now under active development. An optimal performance of these machines requires the preservation of the high beam brightness generated in the injector. For this, the impact of the ionized residual gas on the beam has to be avoided as it causes instabilities and emittance growth. Obviously, the vacuum chamber has to be cleared out of ions but as the potential of the electron beam attracts the ions, it is not enough to install vacuum pumps. One measure for ion clearing are gaps in the bunch train long enough that the ions have time to escape the force of the bunch potential. In this paper, we present numerical studies of the behavior of an ion cloud that interacts with a bunch train. Especially, we consider different distributions for the particles in the bunch, different fill patterns and several mixtures of ions in the residual gas. The simulations are performed with the package MOEVE PIC Tracking. The presented numerical investigations take into account the parameters of the ERL BERLinPro with the objective to deduce appropriate measures for the design and operation of BERLinPro.

WEP15	Tools for Analysis and Improvement of Linac Optics Design for High Brightness Electron Beams	optics, quadrupole, focusing, controls	170
	S. Di Mitri, M. Cornacchia, C. Scafuri ELETTRA, Basovizza, Italy
	The optics design of single pass high brightness electron linacs usually aims at the preservation of the transverse emittance. Collective effects mainly impose constraints to the optics design such as at the low-beta interaction points in colliders and magnetic compressors in FELs. Other constraints are from the trajectory correction scheme, performance of diagnostics, collimation systems and physical space limitations. Strong focusing is typically prescribed for all the aforementioned cases, although it may hamper the main goal of emittance preservation through the excitation of optical aberrations. Strong focusing also potentially leads, through focusing errors, to large beam optics mismatch. Based on these sometimes conflicting requirements, we have developed tools for the analysis and improvement of electron linac optics. They are based on the Elegant [1] code and allow the user to identify: local sources of phase space distortions and emittance dilution, lattice areas particularly sensitive to focusing errors, poor trajectory steering. The analysis does not require massive particle tracking since it deals with the single particle motion in the normalized phase space. [1] M. Borland, Advanced Photon Source LS-287 (2000).

THP09	Global Scan of All Stable Settings (GLASS) for the ANKA Storage Ring	optics, quadrupole, dynamic-aperture, storage-ring	239
	M. Streichert, N. Hiller, E. Huttel, V. Judin, B. Kehrer, M. Klein, S. Marsching, C.A.J. Meuter, A.-S. Müller, M.J. Nasse, M. Schuh, N.J. Smale KIT, Karlsruhe, Germany
	Funding: This work has been supported by the Initiative and Networking Fund of the Helmholtz Association under contract number VH-NG-320. The design of an optimal magnetic optics for a storage ring is not a simple optimization problem, since numerous objectives have to be considered. For instance, figures of merit could be tune values, optical functions, momentum compaction factor, emittance, etc. There is a technique called “GLobal scan of All Stable Settings” (GLASS), which provides a systematic analysis of the magnetic optics and gives a global overview of the capabilities of the storage ring. We developed a parallel version of GLASS, which can run on multi-core processors, decreasing significantly the computational time. In this paper we present our GLASS implementation and show results for the ANKA lattice.

FRAAC4	Astra based Swarm Optimizations of the BERLinPro Injector	linac, cavity, gun, booster	281
	M. Abo-Bakr, B.C. Kuske HZB, Berlin, Germany
	The Berlin Energy Recovery Linac Project BERLinPro is a compact ERL to develop the accelerator physics and technology required to generate and accelerate a 100-mA, 1-mm mrad normalized emittance beam. One of the project challenges is to generate a beam of this kind in the injector part of the machine. Extensive injector optimization studies have been done over the last years. A deep insight in the physics of high brilliance, low energy beams together with single parameter scans allowed for an efficient optimization, resulting in a layout, capable to deliver bunches of the needed charge and dimension. However, changes in the injector components' technical layout, as they are unavoidable in the current stage of the project, may require re-optimizations at any time, if necessary of the whole injector part. To support these work an ASTRA based 'swarm optimization' tool for massive parallel calculations on the institutes Linux computing cluster has been developed. Once the optimization wrapper code is written, results come for free and can help to extend the understanding of the underlying physics. Strategy, procedure and results of the 'swarm optimizations' will be presented in this paper.
	Slides FRAAC4 [7.286 MB]

Paper

Title

Other Keywords

Page

MOACC3

Tracking of a PETRA III Positron Bunch with a Pre-Computed Wake Matrix due to Electron Clouds

simulation, electron, positron, wakefield

31

A. Markoviḱ, U. van Rienen
Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany

Funding: Work supported by DFG under contract number RI 814/20-2.
At the synchrotron radiation facility at DESY transversal tune spectra have been observed which are characteristic for an interaction of the positron beam with possible electron clouds in the ring. The filling patterns at which this incoherent tune shifts happen are favourable to the growth of the electron density, i.e. long bunch trains with short intra-bunch distances or filling with short trains but also short distances between the trains. Eventually the vertical emittance growth with the originally designed equidistant filling (with 8 or 16 ns bunch spacing) has been avoided by fillings with shorter trains and longer gaps between the trains by still achieving the designed beam current of 100 mA. In this paper we examine the positron bunch stability of PETRA III for certain e-cloud densities and bunch parameters. A PIC simulation of the interaction of the bunch with an e-cloud yields the wake kick on the tail particles for an offset in the transverse centroid position of the head parts. With such a pre-computed wake matrix, we investigate the stability of a single bunch by tracking it through the linear optics of the ring while at each turn applying the kick from the e-cloud.

Slides MOACC3 [5.237 MB]

MOSCC2

Simulation of Space Effects During Multiturn Injection into the GSI SIS18 Synchrotron

injection, simulation, space-charge, septum

37

S. Appel
GSI, Darmstadt, Germany
O. Boine-Frankenheim
TEMF, TU Darmstadt, Darmstadt, Germany

The optimization of the Multiturn Injection (MTI) from the UNILAC into the SIS18 is crucial in order to reach the FAIR beam intensities required for heavy ions. In order to achieve the design intensities, the efficiency of the multiturn injection from the UNILAC has to be optimized for high beam currents. We developed a simulation model for the MTI including the closed orbit bump, lattice errors, the parameters of the injected UNILAC beam, the position of the septum and other aperture limiting components, and finally the space charge force and other high-intensity effects. The model is also used to estimate the required proton and heavy-ion beam emittances from the UNILAC and from the projected p-linac. For the accurate prediction of the MTI efficiency a careful validation of the simulation model is necessary. We will present first results of the comparison between experiments and simulation for low and high uranium beam currents.

Slides MOSCC2 [2.511 MB]

TUAAI2

A Massively Parallel General Purpose Multi-objective Optimization Framework, Applied to Beam Dynamic Studies

simulation, status, controls, solenoid

62

Y. Ineichen, A. Adelmann
PSI, Villigen, Switzerland
P. Arbenz
ETH, Zurich, Switzerland
C. Bekas, A. Curioni
IBM Research - Zurich, Rueschlikon, Switzerland

Particle accelerators are invaluable tools for research in basic and applied sciences. The successful design, commissioning, and operation of accelerator facilities is non trivial. We implemented a framework for general simulation-based multi-optimization methods automating the investigation of optimal sets of machine parameters. In order to solve the emerging, huge problems we propose a massively-parallel master/slave approach. We employ the framework to identify optimal parameters of existing and new accelerators at PSI.

Slides TUAAI2 [0.694 MB]

TUABC2

Global Optimization of the ANKA Lattice Using Multiobjective Genetic Algorithms (MOGA)

optics, quadrupole, lattice, storage-ring

72

M. Streichert, N. Hiller, E. Huttel, V. Judin, B. Kehrer, M. Klein, S. Marsching, C.A.J. Meuter, A.-S. Müller, M.J. Nasse, M. Schuh, N.J. Smale
KIT, Karlsruhe, Germany

Funding: This work has been supported by the Initiative and Networking Fund of the Helmholtz Association under contract number VH-NG-320.
The optimization of a storage ring lattice is a multiobjective problem, since the parameter space of possible solutions can be very large and a high number of constraints have to be taken into account during the optimization process. In this paper we used Genetic Algorithms (GA) and MultiObjective Genetic Algorithms (MOGA), which can solve such problems very efficiently and rapidly, to find the optimized settings for the ANKA storage ring lattice.

TUSBC2

Low Noise Particle-in-Cell Simulations of Laser Plasma Accelerator 10 GeV Stages

plasma, simulation, laser, electron

78

E. Cormier-Michel, D.L. Bruhwiler, J.R. Cary, B.M. Cowan, E.J. Hallman
Tech-X, Boulder, Colorado, USA
E. Esarey, C.G.R. Geddes, W. Leemans, C.B. Schroeder, J.-L. Vay
LBNL, Berkeley, California, USA

Funding: Work supported by DOE/HEP, under grants DE-SC0004441 and DE-FC02-07ER41499, including use of NERSC under DE-AC02-05CH11231.
Because of their ultra-high accelerating gradient, laser plasma based accelerators (LPA) are contemplated for the next generation of high-energy colliders and light sources. The upcoming BELLA project will explore acceleration of electron bunches to 10 GeV in a 1 meter long plasma, where a wakefield is driven by a PW-class laser. Particle-in-cell (PIC) simulations are used to design the upcoming experiments where boosted frame simulations are used to model the full scale stages. As criteria on energy spread and beam emittance become more stringent, PIC simulations become more challenging as high frequency noise artificially increases those quantities. We show that calculating the beam self-fields using a static Poisson solve in the beam frame dramatically reduces particle noise, allowing for more accurate simulation of the beam evolution. In particular, this method gets correct cancellation of the transverse self-electric and magnetic fields of the beam, eliminating artificial self-forces, which is usually not true when using the standard PIC algorithm based on the staggered (“Yee”) electromagnetic field solver.

Slides TUSBC2 [5.989 MB]

WEP02

Numerical Studies on the Influence of Fill Patterns on Ion Clouds

ion, electron, simulation, vacuum

146

A. Meseck
HZB, Berlin, Germany
G. Pöplau, U. van Rienen
Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany

Funding: supported by BMBF under contract no. 05K10HRC
Energy Recovery Linacs (ERLs) are the most promising candidates for next-generation light sources now under active development. An optimal performance of these machines requires the preservation of the high beam brightness generated in the injector. For this, the impact of the ionized residual gas on the beam has to be avoided as it causes instabilities and emittance growth. Obviously, the vacuum chamber has to be cleared out of ions but as the potential of the electron beam attracts the ions, it is not enough to install vacuum pumps. One measure for ion clearing are gaps in the bunch train long enough that the ions have time to escape the force of the bunch potential. In this paper, we present numerical studies of the behavior of an ion cloud that interacts with a bunch train. Especially, we consider different distributions for the particles in the bunch, different fill patterns and several mixtures of ions in the residual gas. The simulations are performed with the package MOEVE PIC Tracking. The presented numerical investigations take into account the parameters of the ERL BERLinPro with the objective to deduce appropriate measures for the design and operation of BERLinPro.

WEP15

Tools for Analysis and Improvement of Linac Optics Design for High Brightness Electron Beams

optics, quadrupole, focusing, controls

170

S. Di Mitri, M. Cornacchia, C. Scafuri
ELETTRA, Basovizza, Italy

The optics design of single pass high brightness electron linacs usually aims at the preservation of the transverse emittance. Collective effects mainly impose constraints to the optics design such as at the low-beta interaction points in colliders and magnetic compressors in FELs. Other constraints are from the trajectory correction scheme, performance of diagnostics, collimation systems and physical space limitations. Strong focusing is typically prescribed for all the aforementioned cases, although it may hamper the main goal of emittance preservation through the excitation of optical aberrations. Strong focusing also potentially leads, through focusing errors, to large beam optics mismatch. Based on these sometimes conflicting requirements, we have developed tools for the analysis and improvement of electron linac optics. They are based on the Elegant [1] code and allow the user to identify:

local sources of phase space distortions and emittance dilution,
lattice areas particularly sensitive to focusing errors,
poor trajectory steering.

The analysis does not require massive particle tracking since it deals with the single particle motion in the normalized phase space.
[1] M. Borland, Advanced Photon Source LS-287 (2000).

THP09

Global Scan of All Stable Settings (GLASS) for the ANKA Storage Ring

optics, quadrupole, dynamic-aperture, storage-ring

239

M. Streichert, N. Hiller, E. Huttel, V. Judin, B. Kehrer, M. Klein, S. Marsching, C.A.J. Meuter, A.-S. Müller, M.J. Nasse, M. Schuh, N.J. Smale
KIT, Karlsruhe, Germany

Funding: This work has been supported by the Initiative and Networking Fund of the Helmholtz Association under contract number VH-NG-320.
The design of an optimal magnetic optics for a storage ring is not a simple optimization problem, since numerous objectives have to be considered. For instance, figures of merit could be tune values, optical functions, momentum compaction factor, emittance, etc. There is a technique called “GLobal scan of All Stable Settings” (GLASS), which provides a systematic analysis of the magnetic optics and gives a global overview of the capabilities of the storage ring. We developed a parallel version of GLASS, which can run on multi-core processors, decreasing significantly the computational time. In this paper we present our GLASS implementation and show results for the ANKA lattice.

FRAAC4

Astra based Swarm Optimizations of the BERLinPro Injector

linac, cavity, gun, booster

281

M. Abo-Bakr, B.C. Kuske
HZB, Berlin, Germany

The Berlin Energy Recovery Linac Project BERLinPro is a compact ERL to develop the accelerator physics and technology required to generate and accelerate a 100-mA, 1-mm mrad normalized emittance beam. One of the project challenges is to generate a beam of this kind in the injector part of the machine. Extensive injector optimization studies have been done over the last years. A deep insight in the physics of high brilliance, low energy beams together with single parameter scans allowed for an efficient optimization, resulting in a layout, capable to deliver bunches of the needed charge and dimension. However, changes in the injector components' technical layout, as they are unavoidable in the current stage of the project, may require re-optimizations at any time, if necessary of the whole injector part. To support these work an ASTRA based 'swarm optimization' tool for massive parallel calculations on the institutes Linux computing cluster has been developed. Once the optimization wrapper code is written, results come for free and can help to extend the understanding of the underlying physics. Strategy, procedure and results of the 'swarm optimizations' will be presented in this paper.

Slides FRAAC4 [7.286 MB]