LINAC2012 - Classification: 01 Electron Accelerators and Applications / 1E Colliders

Paper

Title

Page

On-Line Dispersion Free Steering for the Main Linac of CLIC

13

J. Pfingstner, D. Schulte
CERN, Geneva, Switzerland

For future linear colliders as well as for light sources, ground motion effects are a severe problem for the accelerator performance. After a few minutes, orbit feedback systems are not sufficient to mitigate all ground motion effects and additional long term methods will have to be deployed. In this paper, the long term ground motion effects in the main linac of the Compact Linear Collider (CLIC) are analysed via simulation studies. The primary growth of the projected emittance is identified to originate from chromatic dilutions due to dispersive beam orbits. To counter this effect, an on-line identification algorithm is applied to measure the dispersion parasitically. This dispersion estimate is used to correct the beam orbit with an iterative dispersion free steering algorithm. The presented results are not only of interest for the CLIC project, but for all linacs in which the dispersive orbit has to be corrected over time.

SUPB008

Specifications of the Distributed Timing System for the CLIC Main Linac

16

A. Gerbershagen, A. Andersson, D. Schulte
CERN, Geneva, Switzerland
P. Burrows
JAI, Oxford, United Kingdom
F.Ö. Ilday
Bilkent University, Bilkent, Ankara, Turkey

The longitudinal phase stability of CLIC main and drive beams is a crucial element of CLIC design. In order to measure and to control the phase, a distributed phase monitoring system has been proposed. The system measures the beam phase every 900 m. The relative phase between the measurement points is synchronized with an external reference system via a chain of reference lines. This paper presents the simulations of error propagation in the proposed distributed monitoring system and the impact on the drive and main beam phase errors and the luminosity. Based on the results the error tolerances for the proposed system are detailed.

MOPLB03

Advances in Beam Tests of Dielectric Based Accelerating Structures

144

A. Kanareykin, S.P. Antipov, J.E. Butler, C.-J. Jing
Euclid TechLabs, LLC, Solon, Ohio, USA
W. Gai
ANL, Argonne, USA
V. Yakimenko
BNL, Upton, Long Island, New York, USA

Funding: US Department of Energy
Diamond is being evaluated as a dielectric material for dielectric loaded accelerating structures. It has a very low microwave loss tangent, high thermal conductivity, and supports high RF breakdown fields. We report on progress in our recent beam tests of the diamond based accelerating structures of the Ka-band and THz frequency ranges. Wakefield breakdown test of a diamond-loaded accelerating structure has been carried out at the ANL/AWA accelerator. The high charge beam from the AWA linac (~70 nC, σ_z = 2.5 mm) was passed through a rectangular diamond loaded resonator and induce an intense wakefield. A groove is cut on the diamond to enhance the field. Electric fields up to 0.3 GV/m has been detected on the diamond surface to attempt to initiate breakdown. A surface analysis of the diamond has been performed before and after the beam test. Wakefield effects in a 250 GHz planar diamond accelerating structure has been observed at BNL/ATF accelerator as well. We have directly measured the mm-wave wake fields induced by subpicosecond, intense relativistic electron bunches in a diamond loaded accelerating structure via the dielectric wake-field acceleration mechanism.

Slides MOPLB03 [1.986 MB]

MOPB041

Advances in Beam Tests of Dielectric Based Accelerating Structures

264

A. Kanareykin, S.P. Antipov, J.E. Butler, C.-J. Jing
Euclid TechLabs, LLC, Solon, Ohio, USA
W. Gai
ANL, Argonne, USA
V. Yakimenko
BNL, Upton, Long Island, New York, USA

Funding: US Department of Energy
Diamond is being evaluated as a dielectric material for dielectric loaded accelerating structures. It has a very low microwave loss tangent, high thermal conductivity, and supports high RF breakdown fields. We report on progress in our recent beam tests of the diamond based accelerating structures of the Ka-band and THz frequency ranges. Wakefield breakdown test of a diamond-loaded accelerating structure has been carried out at the ANL/AWA accelerator. The high charge beam from the AWA linac (~70 nC, σ_z = 2.5 mm) was passed through a rectangular diamond loaded resonator and induce an intense wakefield. A groove is cut on the diamond to enhance the field. Electric fields up to 0.3 GV/m has been detected on the diamond surface to attempt to initiate breakdown. A surface analysis of the diamond has been performed before and after the beam test. Wakefield effects in a 250 GHz planar diamond accelerating structure has been observed at BNL/ATF accelerator as well. We have directly measured the mm-wave wake fields induced by subpicosecond, intense relativistic electron bunches in a diamond loaded accelerating structure via the dielectric wake-field acceleration mechanism.

MOPB042

On-line Dispersion Free Steering for the Main Linac of CLIC

267

J. Pfingstner, D. Schulte
CERN, Geneva, Switzerland

For future linear colliders as well as for light sources, ground motion effects are a severe problem for the accelerator performance. After a few minutes, orbit feedback systems are not sufficient to mitigate all ground motion effects and additional long term methods will have to be deployed. In this paper, the long term ground motion effects in the main linac of the Compact Linear Collider (CLIC) are analysed via simulation studies. The primary growth of the projected emittance is identified to originate from chromatic dilutions due to dispersive beam orbits. To counter this effect, an on-line identification algorithm is applied to measure the dispersion parasitically. This dispersion estimate is used to correct the beam orbit with an iterative dispersion free steering algorithm. The presented results are not only of interest for the CLIC project, but for all linacs in which the dispersive orbit has to be corrected over time.

MOPB043

Detailed Analysis of the Long-Range Wakefield in the Baseline Design of the CLIC Main Linac

270

V.F. Khan, A. Grudiev
CERN, Geneva, Switzerland

The baseline design for the accelerating structure of the CLIC main linac relies on strong damping of transverse higher order modes (HOMs). Each accelerating cell is equipped with four damping waveguides that enables HOM energy to propagate to damping loads. Most of the HOMs decay exponentially with a Q-factor of about 10 however, there are modes with higher Q-factors. Though the amplitude of the high Q modes is nearly two orders of magnitude smaller than the dominating lowest dipole mode, their cumulative effect over the entire bunch train may be significant and dilute the beam emittance to unacceptable level. In this paper we report on an accurate calculation of the long-range wakefield and its overall effect on beam dynamics. We also discuss possible measures to minimise its effect in a tapered structure.

MOPB045

Specifications of the Distributed Timing System for the CLIC Main Linac

273

A. Gerbershagen, A. Andersson, D. Schulte
CERN, Geneva, Switzerland
P. Burrows
JAI, Oxford, United Kingdom
F.Ö. Ilday
Bilkent University, Bilkent, Ankara, Turkey

The longitudinal phase stability of CLIC main and drive beams is a crucial element of CLIC design. In order to measure and to control the phase, a distributed phase monitoring system has been proposed. The system measures the beam phase every 900 m. The relative phase between the measurement points is synchronized with an external reference system via a chain of reference lines. This paper presents the simulations of error propagation in the proposed distributed monitoring system and the impact on the drive and main beam phase errors and the luminosity. Based on the results the error tolerances for the proposed system are detailed.

WE1A02

Status and Future of the CLIC Study

719

R. Corsini
CERN, Geneva, Switzerland

The Compact Linear Collider (CLIC) International Collaboration is carrying out an extensive R&D program towards a multi-TeV electron-positron collider. The CLIC concept is based on the use of high-gradient normal-conducting accelerating structures in conjunction with a novel two-beam acceleration scheme, where the RF power needed to accelerate the colliding beams is extracted from a high-current drive beam running parallel to the main linac. In order to establish the feasibility of such concept a number of key issues were addressed, both experimentally and theoretically, and the results of the study were documented in the recently completed CLIC Conceptual Design Report (CDR). The conclusions reached in the CDR constitute also an important contribution to the European strategy group. A short summary of the present status with will be given, together with an outlook on the program for the next period, aimed at the preparation of an implementation plan.

TH3A01

Status of ILC

787

A. Yamamoto
KEK, Ibaraki, Japan
M.C. Ross
SLAC, Menlo Park, California, USA
N.J. Walker
DESY, Hamburg, Germany

A review of the ILC project with emphasis on the changes in the technical progress report.

Slides TH3A01 [5.396 MB]

TH3A03

ERL-Based Lepton-Hadron Colliders: eRHIC and LHeC

797

F. Zimmermann
CERN, Geneva, Switzerland

This talk will review hadron-ERL collider projects. The LHeC is a plan to collide the LHC beam with electrons or positrons. One scheme for this facility is based on a superconducting recirculating linac with energy recovery. The electron hadron collider eRHIC will collide polarized and unpolarized electrons with a current of 50 mA and energy in the range of 5 GeV to 30 GeV with hadron beams, including heavy ions or polarized light ions of the RHIC storage ring. The electron beam will be generated in an energy recovery linac contained inside the RHIC tunnel, comprising six passes through two linac section of about 2.5 GeV each.

Slides TH3A03 [3.286 MB]

Paper	Title	Page
SUPB007	On-Line Dispersion Free Steering for the Main Linac of CLIC	13
	J. Pfingstner, D. Schulte CERN, Geneva, Switzerland
	For future linear colliders as well as for light sources, ground motion effects are a severe problem for the accelerator performance. After a few minutes, orbit feedback systems are not sufficient to mitigate all ground motion effects and additional long term methods will have to be deployed. In this paper, the long term ground motion effects in the main linac of the Compact Linear Collider (CLIC) are analysed via simulation studies. The primary growth of the projected emittance is identified to originate from chromatic dilutions due to dispersive beam orbits. To counter this effect, an on-line identification algorithm is applied to measure the dispersion parasitically. This dispersion estimate is used to correct the beam orbit with an iterative dispersion free steering algorithm. The presented results are not only of interest for the CLIC project, but for all linacs in which the dispersive orbit has to be corrected over time.

SUPB008	Specifications of the Distributed Timing System for the CLIC Main Linac	16
	A. Gerbershagen, A. Andersson, D. Schulte CERN, Geneva, Switzerland P. Burrows JAI, Oxford, United Kingdom F.Ö. Ilday Bilkent University, Bilkent, Ankara, Turkey
	The longitudinal phase stability of CLIC main and drive beams is a crucial element of CLIC design. In order to measure and to control the phase, a distributed phase monitoring system has been proposed. The system measures the beam phase every 900 m. The relative phase between the measurement points is synchronized with an external reference system via a chain of reference lines. This paper presents the simulations of error propagation in the proposed distributed monitoring system and the impact on the drive and main beam phase errors and the luminosity. Based on the results the error tolerances for the proposed system are detailed.

MOPLB03	Advances in Beam Tests of Dielectric Based Accelerating Structures	144
	A. Kanareykin, S.P. Antipov, J.E. Butler, C.-J. Jing Euclid TechLabs, LLC, Solon, Ohio, USA W. Gai ANL, Argonne, USA V. Yakimenko BNL, Upton, Long Island, New York, USA
	Funding: US Department of Energy Diamond is being evaluated as a dielectric material for dielectric loaded accelerating structures. It has a very low microwave loss tangent, high thermal conductivity, and supports high RF breakdown fields. We report on progress in our recent beam tests of the diamond based accelerating structures of the Ka-band and THz frequency ranges. Wakefield breakdown test of a diamond-loaded accelerating structure has been carried out at the ANL/AWA accelerator. The high charge beam from the AWA linac (~70 nC, σ_z = 2.5 mm) was passed through a rectangular diamond loaded resonator and induce an intense wakefield. A groove is cut on the diamond to enhance the field. Electric fields up to 0.3 GV/m has been detected on the diamond surface to attempt to initiate breakdown. A surface analysis of the diamond has been performed before and after the beam test. Wakefield effects in a 250 GHz planar diamond accelerating structure has been observed at BNL/ATF accelerator as well. We have directly measured the mm-wave wake fields induced by subpicosecond, intense relativistic electron bunches in a diamond loaded accelerating structure via the dielectric wake-field acceleration mechanism.
	Slides MOPLB03 [1.986 MB]

MOPB041	Advances in Beam Tests of Dielectric Based Accelerating Structures	264
	A. Kanareykin, S.P. Antipov, J.E. Butler, C.-J. Jing Euclid TechLabs, LLC, Solon, Ohio, USA W. Gai ANL, Argonne, USA V. Yakimenko BNL, Upton, Long Island, New York, USA
	Funding: US Department of Energy Diamond is being evaluated as a dielectric material for dielectric loaded accelerating structures. It has a very low microwave loss tangent, high thermal conductivity, and supports high RF breakdown fields. We report on progress in our recent beam tests of the diamond based accelerating structures of the Ka-band and THz frequency ranges. Wakefield breakdown test of a diamond-loaded accelerating structure has been carried out at the ANL/AWA accelerator. The high charge beam from the AWA linac (~70 nC, σ_z = 2.5 mm) was passed through a rectangular diamond loaded resonator and induce an intense wakefield. A groove is cut on the diamond to enhance the field. Electric fields up to 0.3 GV/m has been detected on the diamond surface to attempt to initiate breakdown. A surface analysis of the diamond has been performed before and after the beam test. Wakefield effects in a 250 GHz planar diamond accelerating structure has been observed at BNL/ATF accelerator as well. We have directly measured the mm-wave wake fields induced by subpicosecond, intense relativistic electron bunches in a diamond loaded accelerating structure via the dielectric wake-field acceleration mechanism.

MOPB042	On-line Dispersion Free Steering for the Main Linac of CLIC	267
	J. Pfingstner, D. Schulte CERN, Geneva, Switzerland
	For future linear colliders as well as for light sources, ground motion effects are a severe problem for the accelerator performance. After a few minutes, orbit feedback systems are not sufficient to mitigate all ground motion effects and additional long term methods will have to be deployed. In this paper, the long term ground motion effects in the main linac of the Compact Linear Collider (CLIC) are analysed via simulation studies. The primary growth of the projected emittance is identified to originate from chromatic dilutions due to dispersive beam orbits. To counter this effect, an on-line identification algorithm is applied to measure the dispersion parasitically. This dispersion estimate is used to correct the beam orbit with an iterative dispersion free steering algorithm. The presented results are not only of interest for the CLIC project, but for all linacs in which the dispersive orbit has to be corrected over time.

MOPB043	Detailed Analysis of the Long-Range Wakefield in the Baseline Design of the CLIC Main Linac	270
	V.F. Khan, A. Grudiev CERN, Geneva, Switzerland
	The baseline design for the accelerating structure of the CLIC main linac relies on strong damping of transverse higher order modes (HOMs). Each accelerating cell is equipped with four damping waveguides that enables HOM energy to propagate to damping loads. Most of the HOMs decay exponentially with a Q-factor of about 10 however, there are modes with higher Q-factors. Though the amplitude of the high Q modes is nearly two orders of magnitude smaller than the dominating lowest dipole mode, their cumulative effect over the entire bunch train may be significant and dilute the beam emittance to unacceptable level. In this paper we report on an accurate calculation of the long-range wakefield and its overall effect on beam dynamics. We also discuss possible measures to minimise its effect in a tapered structure.

MOPB045	Specifications of the Distributed Timing System for the CLIC Main Linac	273
	A. Gerbershagen, A. Andersson, D. Schulte CERN, Geneva, Switzerland P. Burrows JAI, Oxford, United Kingdom F.Ö. Ilday Bilkent University, Bilkent, Ankara, Turkey
	The longitudinal phase stability of CLIC main and drive beams is a crucial element of CLIC design. In order to measure and to control the phase, a distributed phase monitoring system has been proposed. The system measures the beam phase every 900 m. The relative phase between the measurement points is synchronized with an external reference system via a chain of reference lines. This paper presents the simulations of error propagation in the proposed distributed monitoring system and the impact on the drive and main beam phase errors and the luminosity. Based on the results the error tolerances for the proposed system are detailed.

WE1A02	Status and Future of the CLIC Study	719
	R. Corsini CERN, Geneva, Switzerland
	The Compact Linear Collider (CLIC) International Collaboration is carrying out an extensive R&D program towards a multi-TeV electron-positron collider. The CLIC concept is based on the use of high-gradient normal-conducting accelerating structures in conjunction with a novel two-beam acceleration scheme, where the RF power needed to accelerate the colliding beams is extracted from a high-current drive beam running parallel to the main linac. In order to establish the feasibility of such concept a number of key issues were addressed, both experimentally and theoretically, and the results of the study were documented in the recently completed CLIC Conceptual Design Report (CDR). The conclusions reached in the CDR constitute also an important contribution to the European strategy group. A short summary of the present status with will be given, together with an outlook on the program for the next period, aimed at the preparation of an implementation plan.

TH3A01	Status of ILC	787
	A. Yamamoto KEK, Ibaraki, Japan M.C. Ross SLAC, Menlo Park, California, USA N.J. Walker DESY, Hamburg, Germany
	A review of the ILC project with emphasis on the changes in the technical progress report.
	Slides TH3A01 [5.396 MB]

TH3A03	ERL-Based Lepton-Hadron Colliders: eRHIC and LHeC	797
	F. Zimmermann CERN, Geneva, Switzerland
	This talk will review hadron-ERL collider projects. The LHeC is a plan to collide the LHC beam with electrons or positrons. One scheme for this facility is based on a superconducting recirculating linac with energy recovery. The electron hadron collider eRHIC will collide polarized and unpolarized electrons with a current of 50 mA and energy in the range of 5 GeV to 30 GeV with hadron beams, including heavy ions or polarized light ions of the RHIC storage ring. The electron beam will be generated in an energy recovery linac contained inside the RHIC tunnel, comprising six passes through two linac section of about 2.5 GeV each.
	Slides TH3A03 [3.286 MB]