IPAC2014 - Classification: 01 Circular and Linear Colliders / T12 Beam Injection/Extraction and Transport

Paper	Title	Page
MOPRO023	SuperKEKB Beam abort System	116
	T. Mimashi, N. Iida, M. Kikuchi, T. Mori KEK, Ibaraki, Japan K. Abe Hitachi Power Semiconductor Device, Ltd., Hitachishi, Ibaraki, Japan A. Sasagawa KYOCERA Corporation, Higashiomi-city, Shiga, Japan A. Tokuchi Pulsed Power Japan Laboratory Ltd., Kusatsu-shi Shiga, Japan
	The abort system of the SuperKEKB is described. The beam abort system consists of the beam abort kicker magnets, pulsed quadrupole magnets, a lambertson septum magnet and extracted window. The dumped beam is extracted with beam abort kicker through the extraction window. The pulsed quadrupole magnets make the beam spot size large at the window. The damages of the extraction window is tested with KEKB beam. The pulsed kicker power supply is under development.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO023
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MOPRO024	The Beam Test for the Ti Extraction Window Damage	119
	T. Mimashi, N. Iida, M. Kikuchi KEK, Ibaraki, Japan
	For the SuperKEKB beam abort system, the Ti extraction window will be used. The damage of the extraction window was estimated with KEKB electron beam. Thin Ti plate and Ti alloy plate were tested as candidates of extraction window material. The damages were observed as a function of beam current. From this experiment, the maximum charge density at the extraction window is determined.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO024
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MOPRO025	Electron Beam Injection System for SuperKEKB Main Ring	122
	T. Mori, N. Iida, M. Kikuchi, T. Mimashi, Y. Sakamoto, S. Takasaki, M. Tawada KEK, Ibaraki, Japan
	The SuperKEKB project is in progress toward the initial physics run in the year 2015. It assumes the nano-beam scheme, in which the emittance of the colliding beams is ε=4.6\mbox{nm}. The emittance of the injected beam is ε=1.46\mbox{nm}. To acheave such a low emittance, it is vitally important to preserve the emittance during the transport of the beam from the linac to the main ring. One of the most difficult sections is the injection system. It has been pointed out that the injected beam has possibility of leading to blowup in the ring, which is caused by a beam-beam interaction with the stored positron beam. To avoid the beam blowup, the synchrotron injection is adopted as a backup option. The orbit of the electron injection beam has been designed and the septum magnet prototype has been constructed. The optics study for electron injection and the current R&D status for the septum magnet will be reported in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO025
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MOPRO027	Measurements and Laboratory Tests on a Prototype Stripline Kicker for the CLIC Damping Rings	125
	C. Belver-Aguilar, A. Faus-Golfe IFIC, Valencia, Spain M.J. Barnes, H.A. Day CERN, Geneva, Switzerland F. Toral CIEMAT, Madrid, Spain
	The Pre-Damping Rings (PDRs) and Damping Rings (DRs) of CLIC are required to reduce the beam emittances to the small values required for the main linacs. The injection and extraction, from the PDRs and DRs, are performed by kicker systems. To achieve both low beam coupling impedance and reasonable broadband impedance matching to the electrical circuit, striplines have been chosen for the kicker elements. Prototype striplines have been built: tests and measurements of these striplines have started. The goal of these tests is to characterize, without beam, the electromagnetic response of the striplines. The tests have been carried out at CERN. To study the signal transmission through the striplines, the measured S-parameters have been compared with simulations. In addition, measurements of longitudinal beam coupling impedance, using the coaxial wire method, are reported and compared with simulations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO027
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MOPRO029	Feed Forward Orbit Correction in the CLIC Ring to Main LINAC Transfer Lines	131
	R. Apsimon, A. Latina, D. Schulte, J.A. Uythoven CERN, Geneva, Switzerland
	The emittance growth in the betatron collimation system of the 27 km long transfer lines between the CLIC damping rings and the main LINAC depends strongly on the transverse orbit jitter. The resulting stability requirements of the damping ring extraction elements seem extremely difficult to achieve. Position and angle feed forward systems in these long transfer lines bring the specified parameters of the extraction elements within reach. The designs of the optics and feed forward hardware are presented together with tracking simulations of the systems.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO029
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MOPRO030	Changes to the LHC Beam Dumping System for LHC Run 2	134
	J.A. Uythoven, M.G. Atanasov, J. Borburgh, E. Carlier, S. Gabourin, B. Goddard, N. Magnin, V. Senaj, N. Voumard, W.J.M. Weterings CERN, Geneva, Switzerland
	The LHC beam dumping system performed according to expectations during Run 1 of the LHC (2009 – 2013). A brief overview of the experience is given, including a summary of the observed performance in comparison to expectations. An important number of changes are applied to the beam dumping system during the present Long Shutdown on order to further improve its system safety and performance. They include the addition of a direct link between the Beam Interlock System and the re-triggering system of the dump kickers, the modification of the uninterrupted electrical power distribution architecture, the upgrade of the HV generators, the consolidation of the trigger synchronization system, the modifications to the triggering system of the power switches and the changes to the dump absorbers TCDQ.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO030
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MOPRO031	Abort Gap Cleaning for LHC Run 2	138
	J.A. Uythoven, A. Boccardi, E. Bravin, B. Goddard, G.H. Hemelsoet, W. Höfle, D. Jacquet, V. Kain, S. Mazzoni, M. Meddahi, D. Valuch CERN, Geneva, Switzerland E. Gianfelice-Wendt Fermilab, Batavia, Illinois, USA
	To minimize the beam losses at the moment of an LHC beam dump the 3 μs long abort gap should contain as few particles as possible. Its population can be minimised by abort gap cleaning using the LHC transverse damper system. The LHC Run 1 experience is briefly recalled; changes foreseen for the LHC Run 2 are presented. They include improvements in the observation of the abort gap population and the mechanism to decide if cleaning is required, changes to the hardware of the transverse dampers to reduce the detrimental effect on the luminosity lifetime and proposed changes to the applied cleaning algorithms.
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MOPRO032	Upgrades to the LHC Injection and Beam Dumping Systems for the HL-LHC Project	141
	J.A. Uythoven, M.J. Barnes, B. Goddard, J. Hrivnak, A. Lechner, F.L. Maciariello, A. Mereghetti, A. Perillo Marcone, N.V. Shetty, G.E. Steele CERN, Geneva, Switzerland
	The HL-LHC project will push the performance of the LHC injection and beam dumping systems towards new limits. This paper describes the systems affected and presents the new beam parameters for these systems. It also describes the studies to be performed to determine which sub-components of these systems need to be upgraded to fulfill the new HL-LHC requirements. The results from the preliminary upgrade studies for the injection absorbers TDI are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO032
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MOPME049	Design Considerations of the Final Turnaround Regions for the CLIC Drive Beam	485
	R. Apsimon, J. Esberg, A. Latina, D. Schulte, J.A. Uythoven CERN, Geneva, Switzerland
	The optics design of the final turnaround regions for the CLIC drive beam is presented. This includes the extraction region, the turnaround loop and the phase feed forward chicane for correcting errors on the bunch phase. The design specifications of the kicker and septum magnets are provided. Tracking simulations and detailed studies of coherent and incoherent synchrotron radiation have been used to optimise the optics in the turnaround region in order to minimise transverse and longitudinal emittance growth.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME049
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MOPRI099	Feasibility Studies for 100 GeV Beam Transfer Lines for a CERN Neutrino Facility	849
	M. Kowalska, W. Bartmann, C. Bracco, B. Goddard, M. Nessi, R. Steerenberg, F.M. Velotti CERN, Geneva, Switzerland
	For a potential future CERN neutrino facility it is considered to extract a 100 GeV proton beam from the second long straight section in the SPS into the existing TT20 transfer line leading to the North Area. Two transfer line design options were developed simultaneously: early-branching from TT20 using existing, recuperated ‘experimental area’ DC dipoles and alternatively late-branching close to the target area, which requires superconducting magnets. This paper describes the feasibility of the two concepts in addition to the detailed study of the early-branching option. Optics and line geometry optimization are discussed and orbit correction is presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI099
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MOPRI100	Investigations of SPS Orbit Drifts	852
	L.N. Drøsdal, C. Bracco, K. Cornelis, B. Goddard, V. Kain, M. Meddahi, J. Wenninger CERN, Geneva, Switzerland E. Gianfelice-Wendt Fermilab, Batavia, Illinois, USA
	The LHC is filled from the last pre-injector, the Super Proton Synchrotron (SPS), via two 3 km long transfer lines, TI 2 and TI 8. Over the LHC injection processes, a drift of the beam trajectories has been observed in TI 2 and TI 8, requiring regular correction of the trajectories, in order to ensure clean injection into the LHC. Investigations of the trajectory variations in the transfer lines showed that the main source of short term trajectory drifts are current variations of the SPS extraction septa (MSE). The stability of the power converters has been improved, but the variations are still present and further improvements are being investigated. The stability over a longer period of time cannot be explained by this source alone. The analysis of trajectory variations shows that there are also slow variations in the SPS closed orbit at extraction. A set of SPS orbit measurements has been saved and analysed. These observations will be used together with simulations and observed field errors to locate the second source of variations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI100
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Paper

Title

Page

SuperKEKB Beam abort System

116

T. Mimashi, N. Iida, M. Kikuchi, T. Mori
KEK, Ibaraki, Japan
K. Abe
Hitachi Power Semiconductor Device, Ltd., Hitachishi, Ibaraki, Japan
A. Sasagawa
KYOCERA Corporation, Higashiomi-city, Shiga, Japan
A. Tokuchi
Pulsed Power Japan Laboratory Ltd., Kusatsu-shi Shiga, Japan

The abort system of the SuperKEKB is described. The beam abort system consists of the beam abort kicker magnets, pulsed quadrupole magnets, a lambertson septum magnet and extracted window. The dumped beam is extracted with beam abort kicker through the extraction window. The pulsed quadrupole magnets make the beam spot size large at the window. The damages of the extraction window is tested with KEKB beam. The pulsed kicker power supply is under development.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO023

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MOPRO024

The Beam Test for the Ti Extraction Window Damage

119

T. Mimashi, N. Iida, M. Kikuchi
KEK, Ibaraki, Japan

For the SuperKEKB beam abort system, the Ti extraction window will be used. The damage of the extraction window was estimated with KEKB electron beam. Thin Ti plate and Ti alloy plate were tested as candidates of extraction window material. The damages were observed as a function of beam current. From this experiment, the maximum charge density at the extraction window is determined.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO024

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MOPRO025

Electron Beam Injection System for SuperKEKB Main Ring

122

T. Mori, N. Iida, M. Kikuchi, T. Mimashi, Y. Sakamoto, S. Takasaki, M. Tawada
KEK, Ibaraki, Japan

The SuperKEKB project is in progress toward the initial physics run in the year 2015. It assumes the nano-beam scheme, in which the emittance of the colliding beams is ε=4.6\mbox{nm}. The emittance of the injected beam is ε=1.46\mbox{nm}. To acheave such a low emittance, it is vitally important to preserve the emittance during the transport of the beam from the linac to the main ring. One of the most difficult sections is the injection system. It has been pointed out that the injected beam has possibility of leading to blowup in the ring, which is caused by a beam-beam interaction with the stored positron beam. To avoid the beam blowup, the synchrotron injection is adopted as a backup option. The orbit of the electron injection beam has been designed and the septum magnet prototype has been constructed. The optics study for electron injection and the current R&D status for the septum magnet will be reported in this paper.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO025

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MOPRO027

Measurements and Laboratory Tests on a Prototype Stripline Kicker for the CLIC Damping Rings

125

C. Belver-Aguilar, A. Faus-Golfe
IFIC, Valencia, Spain
M.J. Barnes, H.A. Day
CERN, Geneva, Switzerland
F. Toral
CIEMAT, Madrid, Spain

The Pre-Damping Rings (PDRs) and Damping Rings (DRs) of CLIC are required to reduce the beam emittances to the small values required for the main linacs. The injection and extraction, from the PDRs and DRs, are performed by kicker systems. To achieve both low beam coupling impedance and reasonable broadband impedance matching to the electrical circuit, striplines have been chosen for the kicker elements. Prototype striplines have been built: tests and measurements of these striplines have started. The goal of these tests is to characterize, without beam, the electromagnetic response of the striplines. The tests have been carried out at CERN. To study the signal transmission through the striplines, the measured S-parameters have been compared with simulations. In addition, measurements of longitudinal beam coupling impedance, using the coaxial wire method, are reported and compared with simulations.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO027

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MOPRO029

Feed Forward Orbit Correction in the CLIC Ring to Main LINAC Transfer Lines

131

R. Apsimon, A. Latina, D. Schulte, J.A. Uythoven
CERN, Geneva, Switzerland

The emittance growth in the betatron collimation system of the 27 km long transfer lines between the CLIC damping rings and the main LINAC depends strongly on the transverse orbit jitter. The resulting stability requirements of the damping ring extraction elements seem extremely difficult to achieve. Position and angle feed forward systems in these long transfer lines bring the specified parameters of the extraction elements within reach. The designs of the optics and feed forward hardware are presented together with tracking simulations of the systems.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO029

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MOPRO030

Changes to the LHC Beam Dumping System for LHC Run 2

134

J.A. Uythoven, M.G. Atanasov, J. Borburgh, E. Carlier, S. Gabourin, B. Goddard, N. Magnin, V. Senaj, N. Voumard, W.J.M. Weterings
CERN, Geneva, Switzerland

The LHC beam dumping system performed according to expectations during Run 1 of the LHC (2009 – 2013). A brief overview of the experience is given, including a summary of the observed performance in comparison to expectations. An important number of changes are applied to the beam dumping system during the present Long Shutdown on order to further improve its system safety and performance. They include the addition of a direct link between the Beam Interlock System and the re-triggering system of the dump kickers, the modification of the uninterrupted electrical power distribution architecture, the upgrade of the HV generators, the consolidation of the trigger synchronization system, the modifications to the triggering system of the power switches and the changes to the dump absorbers TCDQ.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO030

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MOPRO031

Abort Gap Cleaning for LHC Run 2

138

J.A. Uythoven, A. Boccardi, E. Bravin, B. Goddard, G.H. Hemelsoet, W. Höfle, D. Jacquet, V. Kain, S. Mazzoni, M. Meddahi, D. Valuch
CERN, Geneva, Switzerland
E. Gianfelice-Wendt
Fermilab, Batavia, Illinois, USA

To minimize the beam losses at the moment of an LHC beam dump the 3 μs long abort gap should contain as few particles as possible. Its population can be minimised by abort gap cleaning using the LHC transverse damper system. The LHC Run 1 experience is briefly recalled; changes foreseen for the LHC Run 2 are presented. They include improvements in the observation of the abort gap population and the mechanism to decide if cleaning is required, changes to the hardware of the transverse dampers to reduce the detrimental effect on the luminosity lifetime and proposed changes to the applied cleaning algorithms.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO031

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MOPRO032

Upgrades to the LHC Injection and Beam Dumping Systems for the HL-LHC Project

141

J.A. Uythoven, M.J. Barnes, B. Goddard, J. Hrivnak, A. Lechner, F.L. Maciariello, A. Mereghetti, A. Perillo Marcone, N.V. Shetty, G.E. Steele
CERN, Geneva, Switzerland

The HL-LHC project will push the performance of the LHC injection and beam dumping systems towards new limits. This paper describes the systems affected and presents the new beam parameters for these systems. It also describes the studies to be performed to determine which sub-components of these systems need to be upgraded to fulfill the new HL-LHC requirements. The results from the preliminary upgrade studies for the injection absorbers TDI are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO032

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

MOPME049

Design Considerations of the Final Turnaround Regions for the CLIC Drive Beam

485

R. Apsimon, J. Esberg, A. Latina, D. Schulte, J.A. Uythoven
CERN, Geneva, Switzerland

The optics design of the final turnaround regions for the CLIC drive beam is presented. This includes the extraction region, the turnaround loop and the phase feed forward chicane for correcting errors on the bunch phase. The design specifications of the kicker and septum magnets are provided. Tracking simulations and detailed studies of coherent and incoherent synchrotron radiation have been used to optimise the optics in the turnaround region in order to minimise transverse and longitudinal emittance growth.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME049

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MOPRI099

Feasibility Studies for 100 GeV Beam Transfer Lines for a CERN Neutrino Facility

849

M. Kowalska, W. Bartmann, C. Bracco, B. Goddard, M. Nessi, R. Steerenberg, F.M. Velotti
CERN, Geneva, Switzerland

For a potential future CERN neutrino facility it is considered to extract a 100 GeV proton beam from the second long straight section in the SPS into the existing TT20 transfer line leading to the North Area. Two transfer line design options were developed simultaneously: early-branching from TT20 using existing, recuperated ‘experimental area’ DC dipoles and alternatively late-branching close to the target area, which requires superconducting magnets. This paper describes the feasibility of the two concepts in addition to the detailed study of the early-branching option. Optics and line geometry optimization are discussed and orbit correction is presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI099

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MOPRI100

Investigations of SPS Orbit Drifts

852

L.N. Drøsdal, C. Bracco, K. Cornelis, B. Goddard, V. Kain, M. Meddahi, J. Wenninger
CERN, Geneva, Switzerland
E. Gianfelice-Wendt
Fermilab, Batavia, Illinois, USA

The LHC is filled from the last pre-injector, the Super Proton Synchrotron (SPS), via two 3 km long transfer lines, TI 2 and TI 8. Over the LHC injection processes, a drift of the beam trajectories has been observed in TI 2 and TI 8, requiring regular correction of the trajectories, in order to ensure clean injection into the LHC. Investigations of the trajectory variations in the transfer lines showed that the main source of short term trajectory drifts are current variations of the SPS extraction septa (MSE). The stability of the power converters has been improved, but the variations are still present and further improvements are being investigated. The stability over a longer period of time cannot be explained by this source alone. The analysis of trajectory variations shows that there are also slow variations in the SPS closed orbit at extraction. A set of SPS orbit measurements has been saved and analysed. These observations will be used together with simulations and observed field errors to locate the second source of variations.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRI100

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