LINAC2016 - List of Keywords (optics)

Paper	Title	Other Keywords	Page
MO3A02	Achievement of Small Beam Size at ATF2 Beamline	sextupole, wakefield, laser, simulation	27
	T. Okugi KEK, Ibaraki, Japan
	The beam commissioning of the ATF2 facility at KEK - a 1.3 GeV prototype of the compact local chromaticity correction final focus system for the linear collider - achieved 44nm beam size, very close to ideal expected size of 37nm, by developing various knobs and improving the performances of the interferometric Shintake monitor at the same time. These results have opened the way to reliable and predictable operation of the linear collider.
	Slides MO3A02 [3.495 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-MO3A02
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MOPRC008	Dispersion Free and Dispersion Target Steering Experience at CTF3	linac, target, quadrupole, dipole	83
	D. Gamba, R. Corsini, T. Persson, P.K. Skowroński, F. Tecker CERN, Geneva, Switzerland P. Burrows Oxford University, Physics Department, Oxford, Oxon, United Kingdom P. Burrows JAI, Oxford, United Kingdom
	One of the goals of the CLIC Test Facility (CTF3) at CERN is to demonstrate the feasibility of the CLIC Drive Beam recombination, which takes place in the Drive Beam Recombination Complex (DBRC). The tight geometry of the DBRC together with its strong optics and the high energy-spread of the beam require a careful control of the beam size along the different sections of the DBRC. One of the main contribution to beam size is the dispersion. If uncontrolled, dispersion leads to fast increase of the beam size, hence it may affect the beam current stability of the combined beam. A tool has been implemented at CTF3 to measure and correct dispersion during and after the setup of the machine. Dispersion Free Steering (DFS) has been applied in the upstream drive beam LINAC, while Dispersion Target Steering (DTS) has been used in the rings of the DBRC. In the LINAC the weak optics and the wide dynamic aperture of the beamline allow a straightforward correction. In the DBRC the aperture is tighter, and the strong optics produce non-linear dispersion which one needs to take into account. A general overview of current status and future plans in controlling dispersion at CTF3 will be presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-MOPRC008
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MOPRC009	Simulating Apertures in the Uniform Equivalent Beam Model	simulation, quadrupole, space-charge, software	87
	G.H. Gillespie G.H. Gillespie Associates, Inc., Del Mar, California, USA
	The uniform equivalent beam model is useful for simulating particle beam envelopes. Beam root-mean-square (rms) sizes, divergences, and emittances of an equivalent uniform beam approximate well the rms properties of more realistic beam distributions, even in the presence of space charge. Envelope simulation codes for high current beams using the model, such as TRACE 3-D, are central to particle optics design. However, the modeling of apertures has required multi-particle simulation codes. Multi-particle codes do not typically have the fitting and optimization capabilities common to envelope codes, so the evaluation of aperture effects is often a secondary study that may result in further design iteration. To incorporate aperture effects into the optics design at the start, a method has been developed for simulating apertures in the context of a uniform equivalent beam. The method is described and its TRACE 3-D implementation is outlined. Comparisons with multi-particle simulations are used to validate the method and examine regions of applicability.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-MOPRC009
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THOP04	Measurements of the Beam Break-Up Threshold Current at the Recirculating Electron Accelerator S-DALINAC	linac, electron, recirculation, HOM	751
	T. Kürzeder, M. Arnold, L.E. Jürgensen, J. Pforr, N. Pietralla TU Darmstadt, Darmstadt, Germany F. Hug IKP, Mainz, Germany
	Funding: *Supported by the German Federal Ministry for Education and Research (BMBF) under Grant No. 05K13RDA. Linear accelerators, in particular those with a recirculating design and superconducting cavities, have to deal with the problem of Beam Break-Up (BBU). This instability can limit the maximum beam current in such accelerators. Knowing the effectiveness of prevention strategies is of great interest especially for future accelerators like energy recovery linacs (ERL) which aim for high beam currents. One option is to optimize the cavities and higher order mode couplers of those machines. In addition one may adapt the beam line lattice for further suppressing BBU. The superconducting recirculating accelerator S-DALINAC at the Technische Universität Darmstadt provides electron beams in c.w. for nuclear physics experiments since 1991. As the SRF components were never optimized for higher order mode suppression the S-DALINAC suffers from BBU at relatively low beam currents of a few μA. While those currents are sufficient for most nuclear physics experiments we can investigate BBU with respect to the beam optics. We will report on first measurements of threshold currents at different beam energies of the S-DALINAC. The results of a first test to increase the BBU limit by using skew quadrupoles will be presented.
	Slides THOP04 [1.473 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THOP04
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

FR1A01	Fast Envelope Tracking for Space Charge Dominated Injectors	space-charge, linac, TRIUMF, GUI	1017
	R.A. Baartman TRIUMF, Vancouver, Canada
	High brightness injectors are increasingly pushing against space charge effects. Usually, particle tracking codes such as ASTRA, GPT, or PARMELA are used to model these systems however these can be slow to use for detailed optimization. It becomes increasingly challenging in future projects such as LCLS-II where space charge effects are still significant after BC1 and BC2 at 250 and 1600 MeV respectively. This talk will describe an envelope tracking approach that compares well against the particle tracking codes and could facilitate much faster optimization.
	Slides FR1A01 [0.786 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-FR1A01
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Other Keywords

Page

MO3A02

Achievement of Small Beam Size at ATF2 Beamline

sextupole, wakefield, laser, simulation

27

T. Okugi
KEK, Ibaraki, Japan

The beam commissioning of the ATF2 facility at KEK - a 1.3 GeV prototype of the compact local chromaticity correction final focus system for the linear collider - achieved 44nm beam size, very close to ideal expected size of 37nm, by developing various knobs and improving the performances of the interferometric Shintake monitor at the same time. These results have opened the way to reliable and predictable operation of the linear collider.

Slides MO3A02 [3.495 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-MO3A02

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRC008

Dispersion Free and Dispersion Target Steering Experience at CTF3

linac, target, quadrupole, dipole

83

D. Gamba, R. Corsini, T. Persson, P.K. Skowroński, F. Tecker
CERN, Geneva, Switzerland
P. Burrows
Oxford University, Physics Department, Oxford, Oxon, United Kingdom
P. Burrows
JAI, Oxford, United Kingdom

One of the goals of the CLIC Test Facility (CTF3) at CERN is to demonstrate the feasibility of the CLIC Drive Beam recombination, which takes place in the Drive Beam Recombination Complex (DBRC). The tight geometry of the DBRC together with its strong optics and the high energy-spread of the beam require a careful control of the beam size along the different sections of the DBRC. One of the main contribution to beam size is the dispersion. If uncontrolled, dispersion leads to fast increase of the beam size, hence it may affect the beam current stability of the combined beam. A tool has been implemented at CTF3 to measure and correct dispersion during and after the setup of the machine. Dispersion Free Steering (DFS) has been applied in the upstream drive beam LINAC, while Dispersion Target Steering (DTS) has been used in the rings of the DBRC. In the LINAC the weak optics and the wide dynamic aperture of the beamline allow a straightforward correction. In the DBRC the aperture is tighter, and the strong optics produce non-linear dispersion which one needs to take into account. A general overview of current status and future plans in controlling dispersion at CTF3 will be presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-MOPRC008

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPRC009

Simulating Apertures in the Uniform Equivalent Beam Model

simulation, quadrupole, space-charge, software

87

G.H. Gillespie
G.H. Gillespie Associates, Inc., Del Mar, California, USA

The uniform equivalent beam model is useful for simulating particle beam envelopes. Beam root-mean-square (rms) sizes, divergences, and emittances of an equivalent uniform beam approximate well the rms properties of more realistic beam distributions, even in the presence of space charge. Envelope simulation codes for high current beams using the model, such as TRACE 3-D, are central to particle optics design. However, the modeling of apertures has required multi-particle simulation codes. Multi-particle codes do not typically have the fitting and optimization capabilities common to envelope codes, so the evaluation of aperture effects is often a secondary study that may result in further design iteration. To incorporate aperture effects into the optics design at the start, a method has been developed for simulating apertures in the context of a uniform equivalent beam. The method is described and its TRACE 3-D implementation is outlined. Comparisons with multi-particle simulations are used to validate the method and examine regions of applicability.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-MOPRC009

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THOP04

Measurements of the Beam Break-Up Threshold Current at the Recirculating Electron Accelerator S-DALINAC

linac, electron, recirculation, HOM

751

T. Kürzeder, M. Arnold, L.E. Jürgensen, J. Pforr, N. Pietralla
TU Darmstadt, Darmstadt, Germany
F. Hug
IKP, Mainz, Germany

Funding: *Supported by the German Federal Ministry for Education and Research (BMBF) under Grant No. 05K13RDA.
Linear accelerators, in particular those with a recirculating design and superconducting cavities, have to deal with the problem of Beam Break-Up (BBU). This instability can limit the maximum beam current in such accelerators. Knowing the effectiveness of prevention strategies is of great interest especially for future accelerators like energy recovery linacs (ERL) which aim for high beam currents. One option is to optimize the cavities and higher order mode couplers of those machines. In addition one may adapt the beam line lattice for further suppressing BBU. The superconducting recirculating accelerator S-DALINAC at the Technische Universität Darmstadt provides electron beams in c.w. for nuclear physics experiments since 1991. As the SRF components were never optimized for higher order mode suppression the S-DALINAC suffers from BBU at relatively low beam currents of a few μA. While those currents are sufficient for most nuclear physics experiments we can investigate BBU with respect to the beam optics. We will report on first measurements of threshold currents at different beam energies of the S-DALINAC. The results of a first test to increase the BBU limit by using skew quadrupoles will be presented.

Slides THOP04 [1.473 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-THOP04

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

FR1A01

Fast Envelope Tracking for Space Charge Dominated Injectors

space-charge, linac, TRIUMF, GUI

1017

R.A. Baartman
TRIUMF, Vancouver, Canada

High brightness injectors are increasingly pushing against space charge effects. Usually, particle tracking codes such as ASTRA, GPT, or PARMELA are used to model these systems however these can be slow to use for detailed optimization. It becomes increasingly challenging in future projects such as LCLS-II where space charge effects are still significant after BC1 and BC2 at 250 and 1600 MeV respectively. This talk will describe an envelope tracking approach that compares well against the particle tracking codes and could facilitate much faster optimization.

Slides FR1A01 [0.786 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2016-FR1A01

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)