IPAC2011 - List of Keywords (brightness)

Paper	Title	Other Keywords	Page
MOPC067	X-Band Test Station at Lawrence Livermore National Laboratory	electron, klystron, cathode, laser	235
	R.A. Marsh, F. Albert, S.G. Anderson, C.P.J. Barty, G.K. Beer, R.R. Cross, G.A. Deis, C.A. Ebbers, D.J. Gibson, F.V. Hartemann, T.L. Houck LLNL, Livermore, California, USA C. Adolphsen, A.E. Candel, T.S. Chu, E.N. Jongewaard, Z. Li, C. Limborg-Deprey, T.O. Raubenheimer, S.G. Tantawi, A.E. Vlieks, F. Wang, J.W. Wang, F. Zhou SLAC, Menlo Park, California, USA
	Funding: This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. An X-band multi-bunch test station is being built at LLNL to investigate the science and technology paths required to boost the current mono-energetic gamma-ray (MEGa-Ray) brightness by orders of magnitude. The test station will consist of a 5.5 cell X-band RF photoinjector, single accelerator section, and beam diagnostics. Beam quality must be exceedingly high in order to produce narrow-bandwidth gamma-rays, requiring a robust state of the art photoinjector. The photoinjector will be a high gradient (200 MV/m peak surface field on the cathode) standing wave structure, featuring a dual feed racetrack coupler, elliptical irises, and an optimized first cell length. A solid-state Scandinova modulator will power a single SLAC XL4 11.424 GHz 50 MW klystron. RF distribution will allow for full powering of the photoinjector with the balance of the RF powering a single accelerator section so that the electron parameters can be measured. The status of the facility will be presented including commissioning schedule and first experiment plans. Future experimental programs pertinent to Compton scattering R&D, high gradient structure testing, and light source development will be discussed.

TUPS105	Beam Brightness Booster with Self-Stabilization of Electron-Proton Instability	ion, electron, space-charge, proton	1789
	V.G. Dudnikov, C.M. Ankenbrandt Muons, Inc, Batavia, USA
	The brightness and intensity of a circulating proton beam now can be increased up to the space charge tune shift limit by means of charge exchange injection or by electron cooling but cannot be increased above this limit. Significantly higher brightness can be produced by means of charge exchange injection with space charge compensation. The brightness of the space charge compensated beam is limited at low level by an electron-proton (e-p) instability. Fortunately, the e-p instability can be self-stabilized at a high beam density. The “cesiation effect” significantly increases negative ion emission from gas discharges, and surface-plasma sources for intense high brightness negative ion beam production have been developed. These developments make it possible to produce stable “superintense” circulating beams with intensity and brightness far above the space charge limit. A beam brightness booster (BBB) for significant increases of accumulated beam brightness is discussed. Superintense beam production can be simplified by developing a nonlinear nearly-integrable focusing system with broad betatron tune spread and a broadband feedback system for e-p instability suppression. M. Reiser, “Theory and Design of Charged Particle Beam”, second edition, p. 565-570, Wiley-VCH, (2006).

WEODA01	Observations of Beam-beam Effects at High Intensities in the LHC	luminosity, emittance, beam-beam-effects, dynamic-aperture	1936
	W. Herr, R. Alemany-Fernandez, R. Giachino, G. Papotti, T. Pieloni CERN, Geneva, Switzerland R. Calaga BNL, Upton, Long Island, New York, USA E. Laface ESS, Lund, Sweden M. Schaumann RWTH, Aachen, Germany
	First observations with colliding beams in the LHC with bunch intensities close to nominal and above are reported. In 2010 the LHC initially operated with few bunches spaced around the circumference. Beam-beam tune shifts exceeding significantly the design value have been observed. In a later stage crossing angles were introduced around the experiments to allow the collisions of bunch trains. We report the first experience with head-on as well as long range interactions of high intensity bunches and discuss the possible performance reach.
	Slides WEODA01 [0.409 MB]

WEOAB01	Highly Polarized and High Quantum Efficiency Electron Source Using Transmission-type Photocathode	electron, laser, gun, polarization	1950
	N. Yamamoto, F. Ichihashi, A. Mano, T. Nakanishi, Y. Takeda, T. Ujihara Nagoya University, Nagoya, Japan X.G. Jin Institute for Advanced Research, Nagoya, Japan
	The GaAs-type semiconductor photocathodes (PCs) with a negative electron affinity surface have been used as a polarized electron source and are expected as electron sources for next generation accelerators, such as Linear Colliders and Energy Recovery Linacs. Recently, we have developed transmission-type photocathodes (T-PCs).　By using T-PCs, polarized electron beam is extracted from the back-side of laser irradiation-side.　This scheme offers great merits in designing electron guns, such as short focusing of the laser light for a high brilliance electron beam and a simple geometrical structure avoiding an interference problem between the laser and the electron beam. The layer structure of the MOVPE-grown superlattice photocathode and the performance of 90% polarization, a super high brilliance, and a high quantum efficiency will be reported.
	Slides WEOAB01 [6.007 MB]

WEPC102	Recent Developments for Efficient 3D Space Charge Computations Based on Adaptive Multigrid Discretizations	space-charge, simulation, injection, optics	2253
	G. Pöplau, U. van Rienen Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany M.J. de Loos TUE, Eindhoven, The Netherlands S.B. van der Geer Pulsar Physics, Eindhoven, The Netherlands
	Funding: Partly supported by BMBF under contract number 05K10HRC Efficient and accurate space-charge computations are essential for the design of high-brightness charged particle sources. Recently a new adaptive meshing strategy based on multigrid was implemented in GPT and the capabilities were demonstrated. This new meshing scheme uses the solution of an intermediate step in the multigrid algorithm itself to define optimal mesh line positions. In this paper we discuss further developments of this adaptive meshing strategy. We compare the new algorithm with the current meshing scheme of GPT, where the mesh line positions are based upon the projected charge density.

WEPS107	Phase Space Coating in Synchrotrons: Some Applications*	synchrotron, antiproton, emittance, simulation	2763
	C.M. Bhat Fermilab, Batavia, USA
	Funding: Operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy Phase-space painting to produce very high intensity beam in synchrotrons is one of the widely studied topics in accelerator physics. A remarkable example of this is multi-turn beam injection by transverse phase-space painting in spallation sources. Use of barrier buckets at synchrotron storage rings has paved way for further advancements in this field. The Fermilab Recycler, antiproton storage ring, has been augmented with multipurpose broad-band barrier rf systems. Recently we have developed a longitudinal phase-space coating technique over already e-cooled high intensity low longitudinal antiproton beam and demonstrated with beam experiments. This method is extended to map the incoherent synchrotron tune of beam particles in a barrier bucket. Here I review various phase-space painting techniques being used in particle accelerators including some new schemes developed using barrier rf systems and possible new applications.

THPC117	Analysis Quantum Efficiency Spectrum of NEA-GaAs Photocathode	electron, vacuum, cathode, linac	3161
	Y.M. Masumoto, H. Iijima, M. Kuriki HU/AdSM, Higashi-Hiroshima, Japan
	ERL is a future project of synchrotron light source with high brightness and partial coherence. ERL is based on super conducting linear accelerator providing the high brightness electron beam to insertion devices continuously. One of the most difficult technical challenge is the electron source for ERL. A photo-cathode DC biased gun is assumed, but several issues should be solved. One of the issue is the operational lifetime of cathode material, NEA GaAs. NEA stands for Negative electron affinity made by artificial treatment on clean GaAs surface. Emission from the cathode is decreased in time and extracted beam current. In order to research the phenomena, the surface potential is studied by measuring the QE　(Quantum Efficiency) spectrum. Observing temporal evolution of QE, we found that the photon energy threshold did not change during the decay. The spectrum shape was changed suggesting that the surface potential barrier becomes thicker.

THPC150	Review of Insertion Device Dedicated to HIgh Energy Photons at SOLEIL	vacuum, undulator, photon, insertion	3236
	O. Marcouillé, C. Benabderrahmane, P. Berteaud, F. Briquez, L. Chapuis, M.-E. Couprie, T.K. El Ajjouri, F. Marteau, M. Valléau, J. Vétéran SOLEIL, Gif-sur-Yvette, France
	Producing high energy photons between 10 keV and 70 keV is a challenging topic in a medium energy storage ring. It requires up-to-date measurement techniques and specific Insertion Device (ID) technologies to produce high magnetic fields and short periods. SOLEIL (2.75 GeV) has designed and built eight conventional in-vacuum hybrid undulators operating at high radiation harmonics and also one small gap multipole wiggler to produce high magnetic field. The construction has been progressively improved by the choice of new magnetic materials of better quality and higher magnetization, additional correction techniques and mechanical changes. A 2-m long full scale cryogenic undulator made of PrFeB and vanadium permendur has been built, measured, corrected and is to be tested on the beam. An additional wiggler dedicated for Slicing experiments has been designed. The required magnetic field is high enough to also consider the ID as a good candidate for the production of hard X-ray photons. This paper presents the ID dedicated for the high energy photons and their spectral performances.

THPS027	Cesiation in Highly Efficient Surface Plasma Sources	ion, plasma, cathode, ion-source	3478
	V.G. Dudnikov, R.P. Johnson Muons, Inc, Batavia, USA
	Funding: Work supported in part by STTR grant DE-SC0002690. Features of cesiation* in different modifications of H-/D- source designs have been considered. New sources under development include advanced versions of Compact Surface Plasma Sources (CSPS) which will efficiently generate brighter beam in noiseless discharge, deliver significantly increased (up to 20 mA) average current with better electrode cooling using new materials, have significantly extended lifetime and reduced cesium consumption. Related ion sources that use cesium are described and an improved cesiation procedure for reproducible production of high efficiency H⁻ ion generation is considered. * V. Dudnikov, SU Author Certificate, C1.H01 3/04, No. 411542, 10 March, 1972.

Paper

Title

Other Keywords

Page

MOPC067

X-Band Test Station at Lawrence Livermore National Laboratory

electron, klystron, cathode, laser

235

R.A. Marsh, F. Albert, S.G. Anderson, C.P.J. Barty, G.K. Beer, R.R. Cross, G.A. Deis, C.A. Ebbers, D.J. Gibson, F.V. Hartemann, T.L. Houck
LLNL, Livermore, California, USA
C. Adolphsen, A.E. Candel, T.S. Chu, E.N. Jongewaard, Z. Li, C. Limborg-Deprey, T.O. Raubenheimer, S.G. Tantawi, A.E. Vlieks, F. Wang, J.W. Wang, F. Zhou
SLAC, Menlo Park, California, USA

Funding: This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.
An X-band multi-bunch test station is being built at LLNL to investigate the science and technology paths required to boost the current mono-energetic gamma-ray (MEGa-Ray) brightness by orders of magnitude. The test station will consist of a 5.5 cell X-band RF photoinjector, single accelerator section, and beam diagnostics. Beam quality must be exceedingly high in order to produce narrow-bandwidth gamma-rays, requiring a robust state of the art photoinjector. The photoinjector will be a high gradient (200 MV/m peak surface field on the cathode) standing wave structure, featuring a dual feed racetrack coupler, elliptical irises, and an optimized first cell length. A solid-state Scandinova modulator will power a single SLAC XL4 11.424 GHz 50 MW klystron. RF distribution will allow for full powering of the photoinjector with the balance of the RF powering a single accelerator section so that the electron parameters can be measured. The status of the facility will be presented including commissioning schedule and first experiment plans. Future experimental programs pertinent to Compton scattering R&D, high gradient structure testing, and light source development will be discussed.

TUPS105

Beam Brightness Booster with Self-Stabilization of Electron-Proton Instability

ion, electron, space-charge, proton

1789

V.G. Dudnikov, C.M. Ankenbrandt
Muons, Inc, Batavia, USA

The brightness and intensity of a circulating proton beam now can be increased up to the space charge tune shift limit by means of charge exchange injection or by electron cooling but cannot be increased above this limit. Significantly higher brightness can be produced by means of charge exchange injection with space charge compensation*. The brightness of the space charge compensated beam is limited at low level by an electron-proton (e-p) instability. Fortunately, the e-p instability can be self-stabilized at a high beam density. The “cesiation effect” significantly increases negative ion emission from gas discharges, and surface-plasma sources for intense high brightness negative ion beam production have been developed. These developments make it possible to produce stable “superintense” circulating beams with intensity and brightness far above the space charge limit. A beam brightness booster (BBB) for significant increases of accumulated beam brightness is discussed. Superintense beam production can be simplified by developing a nonlinear nearly-integrable focusing system with broad betatron tune spread and a broadband feedback system for e-p instability suppression.
* M. Reiser, “Theory and Design of Charged Particle Beam”, second edition, p. 565-570, Wiley-VCH, (2006).

WEODA01

Observations of Beam-beam Effects at High Intensities in the LHC

luminosity, emittance, beam-beam-effects, dynamic-aperture

1936

W. Herr, R. Alemany-Fernandez, R. Giachino, G. Papotti, T. Pieloni
CERN, Geneva, Switzerland
R. Calaga
BNL, Upton, Long Island, New York, USA
E. Laface
ESS, Lund, Sweden
M. Schaumann
RWTH, Aachen, Germany

First observations with colliding beams in the LHC with bunch intensities close to nominal and above are reported. In 2010 the LHC initially operated with few bunches spaced around the circumference. Beam-beam tune shifts exceeding significantly the design value have been observed. In a later stage crossing angles were introduced around the experiments to allow the collisions of bunch trains. We report the first experience with head-on as well as long range interactions of high intensity bunches and discuss the possible performance reach.

Slides WEODA01 [0.409 MB]

WEOAB01

Highly Polarized and High Quantum Efficiency Electron Source Using Transmission-type Photocathode

electron, laser, gun, polarization

1950

N. Yamamoto, F. Ichihashi, A. Mano, T. Nakanishi, Y. Takeda, T. Ujihara
Nagoya University, Nagoya, Japan
X.G. Jin
Institute for Advanced Research, Nagoya, Japan

The GaAs-type semiconductor photocathodes (PCs) with a negative electron affinity surface have been used as a polarized electron source and are expected as electron sources for next generation accelerators, such as Linear Colliders and Energy Recovery Linacs. Recently, we have developed transmission-type photocathodes (T-PCs).　By using T-PCs, polarized electron beam is extracted from the back-side of laser irradiation-side.　This scheme offers great merits in designing electron guns, such as short focusing of the laser light for a high brilliance electron beam and a simple geometrical structure avoiding an interference problem between the laser and the electron beam. The layer structure of the MOVPE-grown superlattice photocathode and the performance of 90% polarization, a super high brilliance, and a high quantum efficiency will be reported.

Slides WEOAB01 [6.007 MB]

WEPC102

Recent Developments for Efficient 3D Space Charge Computations Based on Adaptive Multigrid Discretizations

space-charge, simulation, injection, optics

2253

G. Pöplau, U. van Rienen
Rostock University, Faculty of Computer Science and Electrical Engineering, Rostock, Germany
M.J. de Loos
TUE, Eindhoven, The Netherlands
S.B. van der Geer
Pulsar Physics, Eindhoven, The Netherlands

Funding: Partly supported by BMBF under contract number 05K10HRC
Efficient and accurate space-charge computations are essential for the design of high-brightness charged particle sources. Recently a new adaptive meshing strategy based on multigrid was implemented in GPT and the capabilities were demonstrated. This new meshing scheme uses the solution of an intermediate step in the multigrid algorithm itself to define optimal mesh line positions. In this paper we discuss further developments of this adaptive meshing strategy. We compare the new algorithm with the current meshing scheme of GPT, where the mesh line positions are based upon the projected charge density.

WEPS107

Phase Space Coating in Synchrotrons: Some Applications*

synchrotron, antiproton, emittance, simulation

2763

C.M. Bhat
Fermilab, Batavia, USA

Funding: Operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy
Phase-space painting to produce very high intensity beam in synchrotrons is one of the widely studied topics in accelerator physics. A remarkable example of this is multi-turn beam injection by transverse phase-space painting in spallation sources. Use of barrier buckets at synchrotron storage rings has paved way for further advancements in this field. The Fermilab Recycler, antiproton storage ring, has been augmented with multipurpose broad-band barrier rf systems. Recently we have developed a longitudinal phase-space coating technique over already e-cooled high intensity low longitudinal antiproton beam and demonstrated with beam experiments. This method is extended to map the incoherent synchrotron tune of beam particles in a barrier bucket. Here I review various phase-space painting techniques being used in particle accelerators including some new schemes developed using barrier rf systems and possible new applications.

THPC117

Analysis Quantum Efficiency Spectrum of NEA-GaAs Photocathode

electron, vacuum, cathode, linac

3161

Y.M. Masumoto, H. Iijima, M. Kuriki
HU/AdSM, Higashi-Hiroshima, Japan

ERL is a future project of synchrotron light source with high brightness and partial coherence. ERL is based on super conducting linear accelerator providing the high brightness electron beam to insertion devices continuously. One of the most difficult technical challenge is the electron source for ERL. A photo-cathode DC biased gun is assumed, but several issues should be solved. One of the issue is the operational lifetime of cathode material, NEA GaAs. NEA stands for Negative electron affinity made by artificial treatment on clean GaAs surface. Emission from the cathode is decreased in time and extracted beam current. In order to research the phenomena, the surface potential is studied by measuring the QE　(Quantum Efficiency) spectrum. Observing temporal evolution of QE, we found that the photon energy threshold did not change during the decay. The spectrum shape was changed suggesting that the surface potential barrier becomes thicker.

THPC150

Review of Insertion Device Dedicated to HIgh Energy Photons at SOLEIL

vacuum, undulator, photon, insertion

3236

O. Marcouillé, C. Benabderrahmane, P. Berteaud, F. Briquez, L. Chapuis, M.-E. Couprie, T.K. El Ajjouri, F. Marteau, M. Valléau, J. Vétéran
SOLEIL, Gif-sur-Yvette, France

Producing high energy photons between 10 keV and 70 keV is a challenging topic in a medium energy storage ring. It requires up-to-date measurement techniques and specific Insertion Device (ID) technologies to produce high magnetic fields and short periods. SOLEIL (2.75 GeV) has designed and built eight conventional in-vacuum hybrid undulators operating at high radiation harmonics and also one small gap multipole wiggler to produce high magnetic field. The construction has been progressively improved by the choice of new magnetic materials of better quality and higher magnetization, additional correction techniques and mechanical changes. A 2-m long full scale cryogenic undulator made of PrFeB and vanadium permendur has been built, measured, corrected and is to be tested on the beam. An additional wiggler dedicated for Slicing experiments has been designed. The required magnetic field is high enough to also consider the ID as a good candidate for the production of hard X-ray photons. This paper presents the ID dedicated for the high energy photons and their spectral performances.

THPS027

Cesiation in Highly Efficient Surface Plasma Sources

ion, plasma, cathode, ion-source

3478

V.G. Dudnikov, R.P. Johnson
Muons, Inc, Batavia, USA

Funding: Work supported in part by STTR grant DE-SC0002690.
Features of cesiation* in different modifications of H-/D- source designs have been considered. New sources under development include advanced versions of Compact Surface Plasma Sources (CSPS) which will efficiently generate brighter beam in noiseless discharge, deliver significantly increased (up to 20 mA) average current with better electrode cooling using new materials, have significantly extended lifetime and reduced cesium consumption. Related ion sources that use cesium are described and an improved cesiation procedure for reproducible production of high efficiency H⁻ ion generation is considered.
* V. Dudnikov, SU Author Certificate, C1.H01 3/04, No. 411542, 10 March, 1972.