IPAC2016 - List of Authors (Adli, E.)

Paper	Title	Page
MOPMR043	Optical System Design for The ESS Proton Beam and Target Diagnostics	347
	M.G. Ibison, C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom E. Adli, H. Gjersdal University of Oslo, Oslo, Norway M.G. Ibison, C.P. Welsch The University of Liverpool, Liverpool, United Kingdom T.J. Shea, C.A. Thomas, N. de la Cour ESS, Lund, Sweden
	Funding: Science and Technology Facilities Council The high power and low emittance of the European Spallation Source (ESS) proton beam require a robust protection strategy for the spallation target and its surroundings. For this, the beam will be imaged on passing through scintillator screens coating both the proton beam window (PBW) on exit from the accelerator, and the entry window to the target (TW). Light from the screens must be transported to remote cameras through a 4m high shielding plug of limited aperture. At the same time, the optical path must not compromise the integrity of the shield against neutrons and interaction products. We present the theory underlying the design of the reflective optics for efficient transmission of high-quality images to provide the desired level of protection to the machine, and describe its implementation in the Zemax software tool, as well as the predicted imaging performance. We also consider how the requirements of environment (thermal and radiation), initial alignment and ongoing maintenance for the optical system will be met. Finally we comment on the applicability of optics of this type for diagnostic systems in similar situations at other neutron sources and elsewhere.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR043
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WEOBB02	Status of Wakefield Monitor Experiments at the CLIC Test Facility	2099
	R.L. Lillestøl, E. Adli, J. Pfingstner University of Oslo, Oslo, Norway N. Aftab, S. Javeed PINSTECH, Islamabad, Pakistan R. Corsini, S. Döbert, W. Farabolini, A. Grudiev, W. Wuensch CERN, Geneva, Switzerland
	For the very low emittance beams in CLIC, it is vital to mitigate emittance growth which leads to reduced luminosity in the detectors. One factor that leads to emittance growth is transverse wakefields in the accelerating structures. In order to combat this the structures must be aligned with a precision of a few um. For achieving this tolerance, accelerating structures are equipped with wakefield monitors that measure higher-order dipole modes excited by the beam when offset from the structure axis. We report on such measurements, performed using prototype CLIC accelerating structures which are part of the module installed in the CLIC Test Facility 3 (CTF3) at CERN. Measurements with and without the drive beam that feeds rf power to the structures are compared. Improvements to the experimental setup are discussed, and finally remaining measurements that should be performed before the completion of the program are summarized.
	Slides WEOBB02 [2.928 MB]
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEOBB02
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WEPMY008	Towards Awake Applications: Electron Beam Acceleration in a Proton Driven Plasma Wake	2557
	E. Adli University of Oslo, Oslo, Norway
	The first phases of the AWAKE experiment will study the wake structure and the potential for electron acceleration in a self-modulated proton driver. In AWAKE Run 2, expected to start after the LHC Long Shut Down 2, electron beam acceleration will be studied. Using a single proton driver and a long acceleration stage, an electron bunch will be accelerated to high energies. Demonstrating beam quality preservation and scalable plasma sources will be a significant step towards using proton driven plasma for applications. We report on the plans and preparations for AWAKE Run 2.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMY008
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WEPMY009	Transverse Tolerances of a Multi-Stage Plasma Wakefield Accelerator	2561
SUPSS034	use link to see paper's listing under its alternate paper code
	C.A. Lindstrøm, E. Adli, J. Pfingstner University of Oslo, Oslo, Norway E. Marín, D. Schulte CERN, Geneva, Switzerland
	Funding: This work is supported by the Research Council of Norway. Plasma wakefield acceleration (PWFA) provides GeV/m-scale accelerating fields, ideal for applications such as a future linear collider. However, strong focusing fields imply that a transversely offset beam with an energy spread will experience emittance growth from the energy dependent betatron oscillation. We develop an analytic model for estimating tolerances from this effect, as well as an effective simplified simulation tool in Elegant. Estimations for a proposed 1 TeV PWFA linear collider scheme indicate tight tolerances of order 40 nm and 1 μrad in position and angle respectively.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMY009
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WEPMY010	Considerations for a Drive Beam Scheme for a Plasma Wakefield Linear Collider	2565
	J. Pfingstner, E. Adli, C.A. Lindstrøm University of Oslo, Oslo, Norway E. Marín, D. Schulte CERN, Geneva, Switzerland
	The potential for high average gradients makes plasma wakefield acceleration (PWFA) an attracting option for future linear colliders. For a beam-driven PWFA collider a sequence of cells has to be supplied with synchronised drive beam bunches. This paper is concerned with the generation, transport and distribution of these drive beam bunches in a so-called drive beam complex for a 3 TeV collider. Based on earlier concepts, several modifications are suggested. The new design includes a superconducting linac and an optimised bunch delay system with a tree structure. To verify the feasibility for the overall complex, a lattice design and tracking studies for the critical bending arc subsystem are presented. Also the feasibility of a compact bunch separation system is shown. The result of these efforts is a drive beam complex that is optimised for construction cost and power efficiency that favours unified lattice solutions.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMY010
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THPPA01	Demonstration of the Hollow Channel Plasma Wakefield Accelerator	3202
SUPSS117	use link to see paper's listing under its alternate paper code
	S.J. Gessner, J.M. Allen, C.I. Clarke, J.-P. Delahaye, J.T. Frederico, S.Z. Green, C. Hast, M.J. Hogan, N. Lipkowitz, M.D. Litos, B.D. O'Shea, D.R. Walz, V. Yakimenko, G. Yocky SLAC, Menlo Park, California, USA E. Adli, C.A. Lindstrøm University of Oslo, Oslo, Norway W. An, C.E. Clayton, C. Joshi, K.A. Marsh, W.B. Mori, N. Vafaei-Najafabadi UCLA, Los Angeles, California, USA S. Corde, A. Doche LOA, Palaiseau, France W. Lu TUB, Beijing, People's Republic of China
	Funding: Work supported by DOE contract DE-AC02-76SF00515. Over the past decade, there has been enormous progress in the field of beam and laser-driven plasma acceleration of electron beams. However, in order for plasma wakefield acceleration to be useful for a high-energy e⁺e^- collider, we need a technique for accelerating positrons in plasma as well. This is a unique challenge, because the plasma responds differently to electron and positron beams, with plasma electrons being pulled through the positron beam and creating a non-linear focusing force. Here, we demonstrate a technique called hollow channel acceleration that symmetrizes the wakefield response to beams of either charge. Using a transversely shaped laser pulse, we create an annular plasma with a fixed radius of 200 μm. We observe the acceleration of a positron bunch with energies up to 33.4 MeV in a 25 cm long channel, indicating an effective gradient greater than 100 MeV/m. This is the first demonstration of a technique that way be used for staged acceleration of positron beams in plasma.
	Slides THPPA01 [5.647 MB]
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPPA01
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Optical System Design for The ESS Proton Beam and Target Diagnostics

347

M.G. Ibison, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
E. Adli, H. Gjersdal
University of Oslo, Oslo, Norway
M.G. Ibison, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom
T.J. Shea, C.A. Thomas, N. de la Cour
ESS, Lund, Sweden

Funding: Science and Technology Facilities Council
The high power and low emittance of the European Spallation Source (ESS) proton beam require a robust protection strategy for the spallation target and its surroundings. For this, the beam will be imaged on passing through scintillator screens coating both the proton beam window (PBW) on exit from the accelerator, and the entry window to the target (TW). Light from the screens must be transported to remote cameras through a 4m high shielding plug of limited aperture. At the same time, the optical path must not compromise the integrity of the shield against neutrons and interaction products. We present the theory underlying the design of the reflective optics for efficient transmission of high-quality images to provide the desired level of protection to the machine, and describe its implementation in the Zemax software tool, as well as the predicted imaging performance. We also consider how the requirements of environment (thermal and radiation), initial alignment and ongoing maintenance for the optical system will be met. Finally we comment on the applicability of optics of this type for diagnostic systems in similar situations at other neutron sources and elsewhere.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR043

Export •

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

WEOBB02

Status of Wakefield Monitor Experiments at the CLIC Test Facility

2099

R.L. Lillestøl, E. Adli, J. Pfingstner
University of Oslo, Oslo, Norway
N. Aftab, S. Javeed
PINSTECH, Islamabad, Pakistan
R. Corsini, S. Döbert, W. Farabolini, A. Grudiev, W. Wuensch
CERN, Geneva, Switzerland

For the very low emittance beams in CLIC, it is vital to mitigate emittance growth which leads to reduced luminosity in the detectors. One factor that leads to emittance growth is transverse wakefields in the accelerating structures. In order to combat this the structures must be aligned with a precision of a few um. For achieving this tolerance, accelerating structures are equipped with wakefield monitors that measure higher-order dipole modes excited by the beam when offset from the structure axis. We report on such measurements, performed using prototype CLIC accelerating structures which are part of the module installed in the CLIC Test Facility 3 (CTF3) at CERN. Measurements with and without the drive beam that feeds rf power to the structures are compared. Improvements to the experimental setup are discussed, and finally remaining measurements that should be performed before the completion of the program are summarized.

Slides WEOBB02 [2.928 MB]

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEOBB02

Export •

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WEPMY008

Towards Awake Applications: Electron Beam Acceleration in a Proton Driven Plasma Wake

2557

E. Adli
University of Oslo, Oslo, Norway

The first phases of the AWAKE experiment will study the wake structure and the potential for electron acceleration in a self-modulated proton driver. In AWAKE Run 2, expected to start after the LHC Long Shut Down 2, electron beam acceleration will be studied. Using a single proton driver and a long acceleration stage, an electron bunch will be accelerated to high energies. Demonstrating beam quality preservation and scalable plasma sources will be a significant step towards using proton driven plasma for applications. We report on the plans and preparations for AWAKE Run 2.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMY008

Export •

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WEPMY009

Transverse Tolerances of a Multi-Stage Plasma Wakefield Accelerator

2561

SUPSS034

use link to see paper's listing under its alternate paper code

C.A. Lindstrøm, E. Adli, J. Pfingstner
University of Oslo, Oslo, Norway
E. Marín, D. Schulte
CERN, Geneva, Switzerland

Funding: This work is supported by the Research Council of Norway.
Plasma wakefield acceleration (PWFA) provides GeV/m-scale accelerating fields, ideal for applications such as a future linear collider. However, strong focusing fields imply that a transversely offset beam with an energy spread will experience emittance growth from the energy dependent betatron oscillation. We develop an analytic model for estimating tolerances from this effect, as well as an effective simplified simulation tool in Elegant. Estimations for a proposed 1 TeV PWFA linear collider scheme indicate tight tolerances of order 40 nm and 1 μrad in position and angle respectively.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMY009

Export •

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

WEPMY010

Considerations for a Drive Beam Scheme for a Plasma Wakefield Linear Collider

2565

J. Pfingstner, E. Adli, C.A. Lindstrøm
University of Oslo, Oslo, Norway
E. Marín, D. Schulte
CERN, Geneva, Switzerland

The potential for high average gradients makes plasma wakefield acceleration (PWFA) an attracting option for future linear colliders. For a beam-driven PWFA collider a sequence of cells has to be supplied with synchronised drive beam bunches. This paper is concerned with the generation, transport and distribution of these drive beam bunches in a so-called drive beam complex for a 3 TeV collider. Based on earlier concepts, several modifications are suggested. The new design includes a superconducting linac and an optimised bunch delay system with a tree structure. To verify the feasibility for the overall complex, a lattice design and tracking studies for the critical bending arc subsystem are presented. Also the feasibility of a compact bunch separation system is shown. The result of these efforts is a drive beam complex that is optimised for construction cost and power efficiency that favours unified lattice solutions.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPMY010

Export •

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

THPPA01

Demonstration of the Hollow Channel Plasma Wakefield Accelerator

3202

SUPSS117

use link to see paper's listing under its alternate paper code

S.J. Gessner, J.M. Allen, C.I. Clarke, J.-P. Delahaye, J.T. Frederico, S.Z. Green, C. Hast, M.J. Hogan, N. Lipkowitz, M.D. Litos, B.D. O'Shea, D.R. Walz, V. Yakimenko, G. Yocky
SLAC, Menlo Park, California, USA
E. Adli, C.A. Lindstrøm
University of Oslo, Oslo, Norway
W. An, C.E. Clayton, C. Joshi, K.A. Marsh, W.B. Mori, N. Vafaei-Najafabadi
UCLA, Los Angeles, California, USA
S. Corde, A. Doche
LOA, Palaiseau, France
W. Lu
TUB, Beijing, People's Republic of China

Funding: Work supported by DOE contract DE-AC02-76SF00515.
Over the past decade, there has been enormous progress in the field of beam and laser-driven plasma acceleration of electron beams. However, in order for plasma wakefield acceleration to be useful for a high-energy e⁺e^- collider, we need a technique for accelerating positrons in plasma as well. This is a unique challenge, because the plasma responds differently to electron and positron beams, with plasma electrons being pulled through the positron beam and creating a non-linear focusing force. Here, we demonstrate a technique called hollow channel acceleration that symmetrizes the wakefield response to beams of either charge. Using a transversely shaped laser pulse, we create an annular plasma with a fixed radius of 200 μm. We observe the acceleration of a positron bunch with energies up to 33.4 MeV in a 25 cm long channel, indicating an effective gradient greater than 100 MeV/m. This is the first demonstration of a technique that way be used for staged acceleration of positron beams in plasma.

Slides THPPA01 [5.647 MB]

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPPA01

Export •

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