IPAC2014 - List of Keywords (brightness)

Paper	Title	Other Keywords	Page
MOXBA01	Challenges in the Design of Diffraction-limited Storage Rings	emittance, lattice, photon, storage-ring	7
	R.O. Hettel SLAC, Menlo Park, California, USA
	This presentation reviews current developments in the design of ultra-low emittance lattices, the experience and challenges with the operation of low emittance lattices and the main technological problems. Beam dynamics issues and collective effects for ultra low emittance machines are also addressed.
	Slides MOXBA01 [6.969 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOXBA01
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MOPRI046	The Evolution of the Transverse Energy Distribution of Electrons from a GaAs Photocathode as a Function of its Degradation State	electron, detector, cathode, laser	707
	L.B. Jones, B.L. Militsyn, T.C.Q. Noakes STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom H.E. Scheibler, A.S. Terekhov ISP, Novosibirsk, Russia
	The brightness of a photoelectron injector is fundamentally limited by the mean longitudinal and transverse energy distributions of the photoelectrons emitted from its photocathode, and the electron beam brightness is increased significantly if the mean values of these quantities are reduced. ASTeC have commissioned a Transverse Energy Spread Spectrometer (TESS – an experimental facility designed to measure these transverse and longitudinal energy distributions) which can be used for III-V semiconductor, alkali antimonide/telluride and metal photocathode research. GaAs photocathodes were activated in our photocathode preparation facility (PPF), then transferred to TESS under XHV conditions and progressively degraded through controlled exposure to oxygen. We present commissioning data and initial measurements showing the evolution of the transverse energy distribution of electrons from GaAs photocathodes as a function of their degradation state. Proc. FEL ’13, TUPPS033, 290-293 ** Proc. IPAC ’11, THPC129, 3185-3187
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI046
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TUPRO010	Origins of Transverse Emittance Blow-up during the LHC Energy Ramp	emittance, luminosity, injection, simulation	1021
	M. Kuhn, G. Arduini, V. Kain, A. Langner, Y. Papaphilippou, M. Schaumann, R. Tomás CERN, Geneva, Switzerland
	During LHC Run 1 about 30 % of the potential peak performance was lost due to transverse emittance blow-up through the LHC cycle. Measurements indicated that the majority of the blow-up occurred during the energy ramp. Until the end of LHC Run 1 this emittance blow-up could not be eliminated. In this paper the measurements and observations of emittance growth through the ramp are summarized. Simulation results for growth due to Intra Beam Scattering will be shown and compared to measurements. A summary of investigations of other possible sources will be given and backed up with simulations where possible. Requirements for commissioning the LHC with beam in 2015 after Long Shutdown 1 to understand and control emittance blow-up will be listed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO010
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TUPRI026	MAX IV Emittance Reduction and Brightness Improvement	optics, emittance, storage-ring, lattice	1615
	S.C. Leemann, M. Eriksson MAX-lab, Lund, Sweden
	With MAX IV construction well underway and storage ring commissioning expected to commence in July 2015, first studies have been launched to improve the optics of the MAX IV 3 GeV storage ring with the goal of further reducing the emittance from the baseline design (328 pm rad) towards 150 pm rad while improving the matching of the electron beam to insertion devices to further improve the resulting photon brightness. We report on progress in the development of this new optics taking into account the strong impact from intrabeam scattering and insertion devices on the resulting equilibrium emittance. We present initial results and sketch a path towards a first MAX IV upgrade.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI026
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WEYB01	Large Dynamic Range Beam Diagnostics for High Average Current Electron LINACs	linac, diagnostics, FEL, optics	1900
	P.E. Evtushenko JLab, Newport News, Virginia, USA
	A number of applications is envisioned now for CW electron LINACs with high average current. A few examples are: driver-accelerators for the next generation of high average brightness SR sources, energy recovery LINACs to be used for frontier research in particle physics - search for dark matter candidate particles, industrial and defense applications. An average beam power of MWs is considered for such applications. Such machines will be required to operate simultaneously with high beam power and peak brightness comparable to the brightest electron beams generated in pulsed LINACs. Combining the high current advantages of storage rings and high peak brightness of LINACs will require such understanding and control of the beam dynamics that 10^-6 fraction of the beam current is taken in to account and controlled during the beam tuning. To make this possible a number of large dynamic range (LDR) (~10⁺⁶) beam diagnostics is under development and test at JLab FEL. Transverse and longitudinal LDR beam profile measurements can be used for LDR measurements of the phase space distribution and its evolution through the accelerator.
	Slides WEYB01 [4.581 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEYB01
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WEPRO005	Development of Superconducting Spoke Cavity for Laser Compton Scattered Photon Sources	cavity, HOM, linac, photon	1946
	M. Sawamura, R. Hajima, R. Nagai JAEA, Ibaraki-ken, Japan H. Fujisawa, Y. Iwashita, H. Tongu Kyoto ICR, Uji, Kyoto, Japan T. Kubo KEK, Ibaraki, Japan
	Funding: This work is supported by Photon and Quantum Basic Research Coordinated Development Program. We have launched a 5-year research program to develop superconducting spoke cavity for laser Compton scattered (LCS) photon sources. For realizing a wide use of LCS X-ray and gamma-ray sources in academic and industrial applications, we adopt 325-MHz superconducting spoke cavity to electron beam drivers for the LCS sources. The spoke cavity, originally invented for ion and proton acceleration, can be used for electron accelerators, in which we can make best use of features of spoke cavity: relative compactness in comparison with a TM cavity of the same frequency, robustness with respect to manufacturing inaccuracy due to its strong cell-to-cell coupling, couplers on outer conductor for the better packing in a linac, and so on. In this paper, we present our research plan and results of cavity shape optimization.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO005
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WEPRO015	RF Injector Beam Dynamics Optimization for LCLS-II	emittance, simulation, linac, cathode	1974
	C. F. Papadopoulos, D. Filippetto, F. Sannibale LBNL, Berkeley, California, USA P. Emma, T.O. Raubenheimer, J.F. Schmerge, L. Wang, F. Zhou SLAC, Menlo Park, California, USA
	Funding: This work was supported in part by the Work supported, in part, by the LCLS-II Project and by the Director of the Office of Science of the US Department of Energy under Contract no. DEAC02-05CH11231 LCLS-II is a proposal for a high repetition rate (>1 MHz) FEL, based on a CW, superconducting linac. The LCLS-II injector is being optimized by a collaboration from Cornell University, Fermilab, LBNL, and SLAC. There are a number of different possible technical choices for the injector including an rf gun or a high voltage DC gun. In this paper we present the status of the simulations for the injector optimization for an rf gun choice for LCLS-II. A multiobjective genetic optimizer is implemented for this reason, and optimized solutions for different bunch charges, corresponding to different operating modes, are presented. These operating points are also the initial part of the start-to-end simulations for LCLS-II. Finally, we discuss the trade-offs between compression and brightness conservation in the low energy (<100 MeV) part of the accelerator, as well as the status of sensitivity studies.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO015
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THPRO096	Nonlinear Oscillations of a Sheet Electron Beam	emittance, electron, plasma, simulation	3113
	H.Y. Barminova MEPhI, Moscow, Russia
	In collisionless approximation the nonlinear dynamics of continuous strong current intense electron beam is investigated. Nonlinear oscillations of the beam radius appear due to self-consistent nonlinear forces. To study these oscillations the model is used that automatically satisfy to Vlasov equation. The oscillations are described by means of Duffing equation. The equilibrium state is shown to exist. The solutions near the equilibrium state are analyzed. The asymptotic character of the solutions is found. Nonlinear beam transverse oscillations lead to filamentation and effective emittance growth. If particle energy dissipation is absent in the beam transportation channel the physical reason of the effective emittance growth is transfer of the part of the beam potential energy to kinetic energy of the particle transverse oscillations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO096
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Other Keywords

Page

MOXBA01

Challenges in the Design of Diffraction-limited Storage Rings

emittance, lattice, photon, storage-ring

7

R.O. Hettel
SLAC, Menlo Park, California, USA

This presentation reviews current developments in the design of ultra-low emittance lattices, the experience and challenges with the operation of low emittance lattices and the main technological problems. Beam dynamics issues and collective effects for ultra low emittance machines are also addressed.

Slides MOXBA01 [6.969 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOXBA01

Export •

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

MOPRI046

The Evolution of the Transverse Energy Distribution of Electrons from a GaAs Photocathode as a Function of its Degradation State

electron, detector, cathode, laser

707

L.B. Jones, B.L. Militsyn, T.C.Q. Noakes
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
H.E. Scheibler, A.S. Terekhov
ISP, Novosibirsk, Russia

The brightness of a photoelectron injector is fundamentally limited by the mean longitudinal and transverse energy distributions of the photoelectrons emitted from its photocathode, and the electron beam brightness is increased significantly if the mean values of these quantities are reduced. ASTeC have commissioned a Transverse Energy Spread Spectrometer (TESS – an experimental facility designed to measure these transverse and longitudinal energy distributions) which can be used for III-V semiconductor, alkali antimonide/telluride and metal photocathode research*. GaAs photocathodes were activated in our photocathode preparation facility (PPF)**, then transferred to TESS under XHV conditions and progressively degraded through controlled exposure to oxygen. We present commissioning data and initial measurements showing the evolution of the transverse energy distribution of electrons from GaAs photocathodes as a function of their degradation state.
* Proc. FEL ’13, TUPPS033, 290-293
** Proc. IPAC ’11, THPC129, 3185-3187

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI046

Export •

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

TUPRO010

Origins of Transverse Emittance Blow-up during the LHC Energy Ramp

emittance, luminosity, injection, simulation

1021

M. Kuhn, G. Arduini, V. Kain, A. Langner, Y. Papaphilippou, M. Schaumann, R. Tomás
CERN, Geneva, Switzerland

During LHC Run 1 about 30 % of the potential peak performance was lost due to transverse emittance blow-up through the LHC cycle. Measurements indicated that the majority of the blow-up occurred during the energy ramp. Until the end of LHC Run 1 this emittance blow-up could not be eliminated. In this paper the measurements and observations of emittance growth through the ramp are summarized. Simulation results for growth due to Intra Beam Scattering will be shown and compared to measurements. A summary of investigations of other possible sources will be given and backed up with simulations where possible. Requirements for commissioning the LHC with beam in 2015 after Long Shutdown 1 to understand and control emittance blow-up will be listed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO010

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TUPRI026

MAX IV Emittance Reduction and Brightness Improvement

optics, emittance, storage-ring, lattice

1615

S.C. Leemann, M. Eriksson
MAX-lab, Lund, Sweden

With MAX IV construction well underway and storage ring commissioning expected to commence in July 2015, first studies have been launched to improve the optics of the MAX IV 3 GeV storage ring with the goal of further reducing the emittance from the baseline design (328 pm rad) towards 150 pm rad while improving the matching of the electron beam to insertion devices to further improve the resulting photon brightness. We report on progress in the development of this new optics taking into account the strong impact from intrabeam scattering and insertion devices on the resulting equilibrium emittance. We present initial results and sketch a path towards a first MAX IV upgrade.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRI026

Export •

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

WEYB01

Large Dynamic Range Beam Diagnostics for High Average Current Electron LINACs

linac, diagnostics, FEL, optics

1900

P.E. Evtushenko
JLab, Newport News, Virginia, USA

A number of applications is envisioned now for CW electron LINACs with high average current. A few examples are: driver-accelerators for the next generation of high average brightness SR sources, energy recovery LINACs to be used for frontier research in particle physics - search for dark matter candidate particles, industrial and defense applications. An average beam power of MWs is considered for such applications. Such machines will be required to operate simultaneously with high beam power and peak brightness comparable to the brightest electron beams generated in pulsed LINACs. Combining the high current advantages of storage rings and high peak brightness of LINACs will require such understanding and control of the beam dynamics that 10^-6 fraction of the beam current is taken in to account and controlled during the beam tuning. To make this possible a number of large dynamic range (LDR) (~10⁺⁶) beam diagnostics is under development and test at JLab FEL. Transverse and longitudinal LDR beam profile measurements can be used for LDR measurements of the phase space distribution and its evolution through the accelerator.

Slides WEYB01 [4.581 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEYB01

Export •

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

WEPRO005

Development of Superconducting Spoke Cavity for Laser Compton Scattered Photon Sources

cavity, HOM, linac, photon

1946

M. Sawamura, R. Hajima, R. Nagai
JAEA, Ibaraki-ken, Japan
H. Fujisawa, Y. Iwashita, H. Tongu
Kyoto ICR, Uji, Kyoto, Japan
T. Kubo
KEK, Ibaraki, Japan

Funding: This work is supported by Photon and Quantum Basic Research Coordinated Development Program.
We have launched a 5-year research program to develop superconducting spoke cavity for laser Compton scattered (LCS) photon sources. For realizing a wide use of LCS X-ray and gamma-ray sources in academic and industrial applications, we adopt 325-MHz superconducting spoke cavity to electron beam drivers for the LCS sources. The spoke cavity, originally invented for ion and proton acceleration, can be used for electron accelerators, in which we can make best use of features of spoke cavity: relative compactness in comparison with a TM cavity of the same frequency, robustness with respect to manufacturing inaccuracy due to its strong cell-to-cell coupling, couplers on outer conductor for the better packing in a linac, and so on. In this paper, we present our research plan and results of cavity shape optimization.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO005

Export •

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

WEPRO015

RF Injector Beam Dynamics Optimization for LCLS-II

emittance, simulation, linac, cathode

1974

C. F. Papadopoulos, D. Filippetto, F. Sannibale
LBNL, Berkeley, California, USA
P. Emma, T.O. Raubenheimer, J.F. Schmerge, L. Wang, F. Zhou
SLAC, Menlo Park, California, USA

Funding: This work was supported in part by the Work supported, in part, by the LCLS-II Project and by the Director of the Office of Science of the US Department of Energy under Contract no. DEAC02-05CH11231
LCLS-II is a proposal for a high repetition rate (>1 MHz) FEL, based on a CW, superconducting linac. The LCLS-II injector is being optimized by a collaboration from Cornell University, Fermilab, LBNL, and SLAC. There are a number of different possible technical choices for the injector including an rf gun or a high voltage DC gun. In this paper we present the status of the simulations for the injector optimization for an rf gun choice for LCLS-II. A multiobjective genetic optimizer is implemented for this reason, and optimized solutions for different bunch charges, corresponding to different operating modes, are presented. These operating points are also the initial part of the start-to-end simulations for LCLS-II. Finally, we discuss the trade-offs between compression and brightness conservation in the low energy (<100 MeV) part of the accelerator, as well as the status of sensitivity studies.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPRO015

Export •

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

THPRO096

Nonlinear Oscillations of a Sheet Electron Beam

emittance, electron, plasma, simulation

3113

H.Y. Barminova
MEPhI, Moscow, Russia

In collisionless approximation the nonlinear dynamics of continuous strong current intense electron beam is investigated. Nonlinear oscillations of the beam radius appear due to self-consistent nonlinear forces. To study these oscillations the model is used that automatically satisfy to Vlasov equation. The oscillations are described by means of Duffing equation. The equilibrium state is shown to exist. The solutions near the equilibrium state are analyzed. The asymptotic character of the solutions is found. Nonlinear beam transverse oscillations lead to filamentation and effective emittance growth. If particle energy dissipation is absent in the beam transportation channel the physical reason of the effective emittance growth is transfer of the part of the beam potential energy to kinetic energy of the particle transverse oscillations.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPRO096

Export •

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