IPAC2014 - List of Keywords (flattop)

Paper	Title	Other Keywords	Page
MOPRO028	Measurements on Prototype Inductive Adders with Ultra-flat-top Output Pulses for CLIC DR Kickers	kicker, damping, operation, high-voltage	128
	J. Holma, M.J. Barnes CERN, Geneva, Switzerland C. Belver-Aguilar IFIC, Valencia, Spain
	The CLIC study is investigating the technical feasibility of an electron-positron collider with high luminosity and a nominal centre-of-mass energy of 3 TeV. The CLIC pre-damping rings and damping rings (DRs) will produce ultra-low emittance beam with high bunch charge. To avoid beam emittance increase, the DR kicker systems must provide extremely flat, high-voltage, pulses. The specifications for the DR extraction kickers call for a 160 ns duration flat-top pulses of ±12.5 kV, 250 A, with a combined ripple and droop of not more than ±0.02 % (±2.5 V). An inductive adder is a very promising approach to meeting the specifications because this topology allows the use of both passive and analogue modulation methods to adjust the output waveform. Recently, two five-layer, 3.5 kV, prototype inductive adders have been built at CERN. The first of these has been used to test the passive and active analogue modulation methods to compensate voltage droop and ripple of the output pulses. Pulse waveforms have been recorded with ±0.05 % relative (±1.0 V) stability for 160 ns flat-top duration at 1.823 kV.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPRO028
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MOPME080	Affordable Short Pulse Marx Modulator	high-voltage, controls, network, linear-collider	557
	R.A. Phillips, G. DelPriore, M.P.J. Gaudreau, M.K. Kempkes Diversified Technologies, Inc., Bedford, Massachusetts, USA J.A. Casey Rockfield Research Inc., Las Vegas, Nevada, USA
	Funding: US Department of Energy, Award DE-SC00004251 High energy, short-pulse modulators are being re-examined for the Compact Linear Collider (CLIC) and numerous X-Band accelerator designs. At the very high voltages required for these systems, all of the existing designs are based on pulse transformers, which significantly limit their performance and efficiency. There is not a fully optimized, transformerless modulator design capable of meeting the demanding requirements of very high voltage pulses at short pulse widths. Under a U.S. Department of Energy grant, Diversified Technologies, Inc. (DTI) is developing a short pulse, solid-state Marx modulator. The modulator is designed for high efficiency in the 100 kV to 500 kV range, for currents up to 250 A, pulse lengths of 0.2 to 5.0 μs, and risetimes <300 ns. Key objectives of the development effort are modularity and scalability, combined with low cost and ease of manufacture. For short-pulse modulators, this Marx topology provides a means to achieve fast risetimes and flattop control that are not available with hard switch or transformer-coupled topologies. The system is in the final stages of testing prior to installation at Yale University.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME080
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MOPME082	ILC-Class Marx Modulator at KEK	controls, high-voltage, damping, operation	562
	M.P.J. Gaudreau, N. Silverman, B.E. Simpson Diversified Technologies, Inc., Bedford, Massachusetts, USA J.A. Casey Rockfield Research Inc., Las Vegas, Nevada, USA
	Funding: US Department of Energy, Award DE-FG02-05ER84352 KEK, High Energy Accelerator Research Organization In October 2013, Diversified Technologies, Inc. (DTI) successfully installed and began operation of a 120 kV, 120 A, 1.7 ms Marx modulator for the High Energy Accelerator Research Organization (KEK) in Japan. Originally conceived, and built under a DOE SBIR grant to support SLAC (completed in 2010), the Marx bank modulator demonstrates a new technology for compact and economic ILC-class performance; the design meets the performance requirements for ILC, does so in a more compact form factor than other known technologies, and, we believe, will be more economic than other technologies. The basic concept of a Marx modulator is that it charges an array of capacitors in parallel (low voltage), then erects them in series to form a high-voltage discharge. Using DTI’s solid-state switches (instead of traditional spark gaps or SCRs) to construct a Marx modulator enables it to open and close; thus the capacitors serve as storage capacitors rather than fully exhausting during each pulse. The opening capability of the DTI switches also provides for arc protection of the load, exactly as they would in a hard-switch. Such a system requires no crowbar protection to protect the load against arcs.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME082
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MOPRI100	Investigations of SPS Orbit Drifts	extraction, septum, injection, betatron	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.
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TUOCA02	Status of the Free Electron Laser User Facility FLASH	FEL, gun, laser, linac	938
	M. Vogt, B. Faatz, J. Feldhaus, K. Honkavaara, S. Schreiber, R. Treusch DESY, Hamburg, Germany
	FLASH, the Free Electron Laser User Facility at DESY (Hamburg, Germany), delivers high brilliance XUV and soft X-ray FEL radiation to photon experiments. After a shutdown to connect the second undulator beamline FLASH2 to the FLASH linac, re-commissioning of FLASH started in autumn 2013. The year 2014 is dedicated to FLASH1 user experiments. The commissioning of the FLASH2 beamline takes place in 2014 in parallel to FLASH1 operation.
	Slides TUOCA02 [9.156 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUOCA02
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TUPRO112	Transient Magnetodynamic Finite Element Analysis of the ISIS M25/2 10Hz Kicker Magnet	simulation, kicker, target, proton	1313
	T.B.J. Mouille STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
	In 2007 a second target station (TS2) was added to the ISIS pulsed neutron source at RAL. Two slow kicker magnets are operated in order to direct a 10Hz proton beam toward TS2 through the TS2 Extract Proton Beam line (EPB2). When first manufactured and tested, the M25/2 exhibited an unforeseen magnetic and thermal behaviour. It was quickly identified that this was caused by the eddy currents induced in the laminated core and the mechanical structure of the magnet. Corrective actions were taken to counterbalance their effects but no further analysis was performed at the time. Recent developments in hardware and software make this analysis more feasible. In this paper we present the results of the transient magnetodynamic simulation that was set up in order to model these eddy currents and study their impact on the M25/2 field quality.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO112
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TUPME049	Hosing Suppression in the Self-modulated Wakefield Accelerator	plasma, wakefield, experiment, controls	1473
	J. Vieira IPFN, Lisbon, Portugal W.B. Mori UCLA, Los Angeles, California, USA P. Muggli MPI, Muenchen, Germany
	Funding: FCT-Portugal contract no EXPL/FIS-PLA/0834/1012; European Research Council contract no ERC-2010-AdG Grant 267841; by DOE contract no DE-SC0008491, DE-SC0008316, and DE-FG02- 92-ER40727. The proton driven plasma wakefield accelerator (PDPWFA) uses short LHC proton (p⁺) bunches (shorter than the plasma wavelength) as drivers for strongly non-linear plasma waves. Simulations showed that the PDPWFA could be used to accelerate electrons to 600 GeVs in 600 m long plasmas. Currently available p⁺ bunches are much longer than the plasma wavelength, being ideal to excite intese wakefields through the self-modulation instability (SMI). An experiment is being prepared at CERN to demonstrate SMI of p⁺ bunches. In addition, lepton SMI experiments are also being prepared at SLAC, DESY-PITZ and RAL. The hosing instability (HI) is a competing instability that may lead to beam breakup, and needs to be controlled over the long propagation distances required for SMI growth and saturation. In this work we show that the HI can be suppressed after SMI saturation in the linear wakefield excitation regime. SMI saturation before beam-break up can be achieved by seeding SMI, and as long as the initial bunch centroid displacements are within the initial bunch transverse size. The HI suppression occurs via a plasma analogue of the BNS damping in conventional accelerators. A. Caldwell et al, Nat. Physics Nat. Phys. 5, 363 (2009).
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPME049
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WEPME021	Solid-state Pulsed Klystron Transmitters	klystron, high-voltage, operation, power-supply	2300
	K. Schrock, C. Chipman, M.P.J. Gaudreau, B.E. Simpson Diversified Technologies, Inc., Bedford, Massachusetts, USA
	Funding: Lawrence Berkeley National Laboratory Daresbury Laboratory Diversified Technologies, Inc. (DTI) is currently building and will deliver in early 2014 two solid-state pulsed klystron transmitters. Though not identical, the units are similar in design, and will be delivered to Lawrence Berkeley National Laboratory (LBNL) and Daresbury Laboratory in England. DTI’s goal across these two projects is to develop a complete package which can subsequently be marketed in the high peak power laboratory transmitter market. The modulator is a pulse transformer-coupled hybrid system, including ancillary klystron components (i.e., focus coil, socket) but not the actual klystron tube. Both systems employ a relatively simple modulator, consisting of an energy storage capacitor, a high voltage series switch, a step-up pulse transformer, and a passive pulse-flattening circuit. This arrangement gives an extremely flat pulse and allows the use of a moderate value of storage capacitor. The DTI switch can open or close as commanded, so the pulse width is adjusted by the gate pulse to the system.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME021
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THOAB01	Recent Progress and Future Plan of Heavy-ion Radiotherapy Facility, HIMAC	ion, operation, synchrotron, heavy-ion	2812
	K. Noda, T. Furukawa, Y. Hara, Y. Iwata, N. Kanematsu, K. Katagiri, A. Kitagawa, K. Mizushima, S. Mori, T. Murakami, M. Muramatsu, M. Nakao, A. Noda, S. Sato, T. Shirai, E. Takada, Y. Takei NIRS, Chiba-shi, Japan
	The first clinical trial with a carbon-ion beam generated from HIMAC was conducted in June 1994. Based on more than ten years of experience with HIMAC, a pilot facility of a standard carbon-ion radiotherapy facility in Japan, was constructed at Gunma University. Owing to the successfully operation of the pilot facility, Saga-HIMAT and i-ROCK in Kanagawa have been progressed. In addition, NIRS has developed the new treatment research project for the further development of radiotherapy with, based on the pencil-beam 3D scanning for both the static and moving targets. This treatment procedure has been successfully carried out with a pencil-beam 3D scanning since May 2011. Owing to the development of NIRS 3D scanning, the i-ROCK project decided to employ the NIRS 3D scanning. As a future plan, further, NIRS has developed a superconducting rotating gantry, and we are going to just start a study of a superconducting accelerator for the ion radiotherapy. The recent progress and the future plan of HIMAC for the heavy-ion cancer radiotherapy will be reported.
	Slides THOAB01 [10.523 MB]
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THPRO043	Studies on the Application of the 3D Ellipsoidal Cathode Laser Pulses at PITZ	laser, booster, electron, emittance	2958
	M. Khojoyan, M. Krasilnikov, F. Stephan DESY Zeuthen, Zeuthen, Germany
	Funding: The work is funded by the German federal Ministry of education and Research, project 05K10CHE “development and experimental test of a laser system for producing quasi 3D ellipsoidal laser pulses”. The Photo Injector Test facility at DESY, Zeuthen Site (PITZ) characterizes and optimizes high brightness electron sources for FLASH and the European XFEL. At nominal conditions the electron bunches are created from a photocathode laser with flat-top temporal distribution and sharp rise and fall times. Beam dynamics simulations using a 3D ellipsoidal cathode laser shape yielded to a significant improvement of the electron beam quality compared to the traditionally used cylindrically shaped beams. The 3D ellipsoidal laser system is under development at the Institute of Applied Physics (IAP) and will be used at PITZ soon, to create high quality electron beams. The recent studies of electron beam simulations at PITZ have been devoted to the position optimization of the second accelerating cavity for the 3D ellipsoidal laser profile. Electron beam properties were compared for cylindrical and 3D ellipsoidal beams applying default and optimized booster positions. Beam tolerance studies revealed much better injector performance for the 3D ellipsoidal laser profile case with the optimized booster position. The outcome of such investigations is presented and discussed in this contribution.
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THPME015	Experimental Performance of an E×B Chopper System	rfq, proton, ion, dipole	3244
	C. Wiesner, H. Dinter, M. Droba, O. Meusel, D. Noll, T. Nowottnick, O. Payir, U. Ratzinger, P.P. Schneider IAP, Frankfurt am Main, Germany
	Beam operation of an E×B chopper system has started in the Low-Energy Beam Transport (LEBT) section of the accelerator-driven neutron source FRANZ. The chopper is designed for low-energy high-perveance beams and high repetition rates. It combines a static magnetic deflection field with a pulsed electric compensation field in a Wien filter-type E×B configuration. Helium ions with 14 keV energy were successfully chopped at the required repetition rate of 257 kHz. The maximum chopped beam intensity of 3.5 mA, limited by the given test ion source, corresponds to a generalized perveance of 2.7·10^-3. For the design species and energy, 120 keV protons, this is equivalent to a beam current of 174 mA. Beam pulses with rise times of 120 ns, flat top lengths of 85 ns to 120 ns and Full Width at Half Maximum (FWHM) between 295 ns and 370 ns were experimentally achieved. U. Ratzinger et al., Proc. of IPAC2011, San Sebastián, Spain, WEPS040. ** C. Wiesner et al. Proc. of IPAC2012, New Orleans, LA., USA, THPPP074.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME015
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THPME095	Length Measurement of High-brightness Electron Beam thanks to the 3-Phase Method	gun, electron, booster, laser	3459
	T. Vinatier, C. Bruni, S. Chancé, P.M. Puzo LAL, Orsay, France
	The goal of 3-phase method is to determine the length of an electron beam without dedicated diagnostics by varying the measurement conditions of its energy spread, through a change in the RF phase of an accelerating structure. The originality here comes from the fact that it is applied on high-brightness electron beams of few MeV generated by RF photo-injectors. It allows testing the accuracy of 3-phase method, since the length to reconstruct is known as being that of the laser pulse generating the beam. It requires establishing the longitudinal transfer matrix of a RF photo-injector, which is difficult since the electron velocity vary from 0 to relativistic during its path. The 3-phase method in RF photo-injector has been simulated by ASTRA and PARMELA codes, validating the principle of the method. First measurement has been done on PHIL accelerator at LAL, showing a good agreement with the expected length. I will then show results obtained at PITZ with a standing wave booster and a comparison with those coming from a Cerenkov detector. Finally, measurements at higher energy performed on the SOLEIL LINAC with travelling wave accelerating structures will be exposed. : K-J. Kim, “RF and Space Charge Effects in Laser-Driven RF Electron Guns”, Nucl. Instr. Meth., A275, 201 (1989)
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Paper

Title

Other Keywords

Page

MOPRO028

Measurements on Prototype Inductive Adders with Ultra-flat-top Output Pulses for CLIC DR Kickers

kicker, damping, operation, high-voltage

128

J. Holma, M.J. Barnes
CERN, Geneva, Switzerland
C. Belver-Aguilar
IFIC, Valencia, Spain

The CLIC study is investigating the technical feasibility of an electron-positron collider with high luminosity and a nominal centre-of-mass energy of 3 TeV. The CLIC pre-damping rings and damping rings (DRs) will produce ultra-low emittance beam with high bunch charge. To avoid beam emittance increase, the DR kicker systems must provide extremely flat, high-voltage, pulses. The specifications for the DR extraction kickers call for a 160 ns duration flat-top pulses of ±12.5 kV, 250 A, with a combined ripple and droop of not more than ±0.02 % (±2.5 V). An inductive adder is a very promising approach to meeting the specifications because this topology allows the use of both passive and analogue modulation methods to adjust the output waveform. Recently, two five-layer, 3.5 kV, prototype inductive adders have been built at CERN. The first of these has been used to test the passive and active analogue modulation methods to compensate voltage droop and ripple of the output pulses. Pulse waveforms have been recorded with ±0.05 % relative (±1.0 V) stability for 160 ns flat-top duration at 1.823 kV.

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MOPME080

Affordable Short Pulse Marx Modulator

high-voltage, controls, network, linear-collider

557

R.A. Phillips, G. DelPriore, M.P.J. Gaudreau, M.K. Kempkes
Diversified Technologies, Inc., Bedford, Massachusetts, USA
J.A. Casey
Rockfield Research Inc., Las Vegas, Nevada, USA

Funding: US Department of Energy, Award DE-SC00004251
High energy, short-pulse modulators are being re-examined for the Compact Linear Collider (CLIC) and numerous X-Band accelerator designs. At the very high voltages required for these systems, all of the existing designs are based on pulse transformers, which significantly limit their performance and efficiency. There is not a fully optimized, transformerless modulator design capable of meeting the demanding requirements of very high voltage pulses at short pulse widths. Under a U.S. Department of Energy grant, Diversified Technologies, Inc. (DTI) is developing a short pulse, solid-state Marx modulator. The modulator is designed for high efficiency in the 100 kV to 500 kV range, for currents up to 250 A, pulse lengths of 0.2 to 5.0 μs, and risetimes <300 ns. Key objectives of the development effort are modularity and scalability, combined with low cost and ease of manufacture. For short-pulse modulators, this Marx topology provides a means to achieve fast risetimes and flattop control that are not available with hard switch or transformer-coupled topologies. The system is in the final stages of testing prior to installation at Yale University.

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MOPME082

ILC-Class Marx Modulator at KEK

controls, high-voltage, damping, operation

562

M.P.J. Gaudreau, N. Silverman, B.E. Simpson
Diversified Technologies, Inc., Bedford, Massachusetts, USA
J.A. Casey
Rockfield Research Inc., Las Vegas, Nevada, USA

Funding: US Department of Energy, Award DE-FG02-05ER84352 KEK, High Energy Accelerator Research Organization
In October 2013, Diversified Technologies, Inc. (DTI) successfully installed and began operation of a 120 kV, 120 A, 1.7 ms Marx modulator for the High Energy Accelerator Research Organization (KEK) in Japan. Originally conceived, and built under a DOE SBIR grant to support SLAC (completed in 2010), the Marx bank modulator demonstrates a new technology for compact and economic ILC-class performance; the design meets the performance requirements for ILC, does so in a more compact form factor than other known technologies, and, we believe, will be more economic than other technologies. The basic concept of a Marx modulator is that it charges an array of capacitors in parallel (low voltage), then erects them in series to form a high-voltage discharge. Using DTI’s solid-state switches (instead of traditional spark gaps or SCRs) to construct a Marx modulator enables it to open and close; thus the capacitors serve as storage capacitors rather than fully exhausting during each pulse. The opening capability of the DTI switches also provides for arc protection of the load, exactly as they would in a hard-switch. Such a system requires no crowbar protection to protect the load against arcs.

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MOPRI100

Investigations of SPS Orbit Drifts

extraction, septum, injection, betatron

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.

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TUOCA02

Status of the Free Electron Laser User Facility FLASH

FEL, gun, laser, linac

938

M. Vogt, B. Faatz, J. Feldhaus, K. Honkavaara, S. Schreiber, R. Treusch
DESY, Hamburg, Germany

FLASH, the Free Electron Laser User Facility at DESY (Hamburg, Germany), delivers high brilliance XUV and soft X-ray FEL radiation to photon experiments. After a shutdown to connect the second undulator beamline FLASH2 to the FLASH linac, re-commissioning of FLASH started in autumn 2013. The year 2014 is dedicated to FLASH1 user experiments. The commissioning of the FLASH2 beamline takes place in 2014 in parallel to FLASH1 operation.

Slides TUOCA02 [9.156 MB]

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TUPRO112

Transient Magnetodynamic Finite Element Analysis of the ISIS M25/2 10Hz Kicker Magnet

simulation, kicker, target, proton

1313

T.B.J. Mouille
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom

In 2007 a second target station (TS2) was added to the ISIS pulsed neutron source at RAL. Two slow kicker magnets are operated in order to direct a 10Hz proton beam toward TS2 through the TS2 Extract Proton Beam line (EPB2). When first manufactured and tested, the M25/2 exhibited an unforeseen magnetic and thermal behaviour. It was quickly identified that this was caused by the eddy currents induced in the laminated core and the mechanical structure of the magnet. Corrective actions were taken to counterbalance their effects but no further analysis was performed at the time. Recent developments in hardware and software make this analysis more feasible. In this paper we present the results of the transient magnetodynamic simulation that was set up in order to model these eddy currents and study their impact on the M25/2 field quality.

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TUPME049

Hosing Suppression in the Self-modulated Wakefield Accelerator

plasma, wakefield, experiment, controls

1473

J. Vieira
IPFN, Lisbon, Portugal
W.B. Mori
UCLA, Los Angeles, California, USA
P. Muggli
MPI, Muenchen, Germany

Funding: FCT-Portugal contract no EXPL/FIS-PLA/0834/1012; European Research Council contract no ERC-2010-AdG Grant 267841; by DOE contract no DE-SC0008491, DE-SC0008316, and DE-FG02- 92-ER40727.
The proton driven plasma wakefield accelerator (PDPWFA) uses short LHC proton (p⁺) bunches (shorter than the plasma wavelength) as drivers for strongly non-linear plasma waves. Simulations showed that the PDPWFA could be used to accelerate electrons to 600 GeVs in 600 m long plasmas*. Currently available p⁺ bunches are much longer than the plasma wavelength, being ideal to excite intese wakefields through the self-modulation instability (SMI). An experiment is being prepared at CERN to demonstrate SMI of p⁺ bunches. In addition, lepton SMI experiments are also being prepared at SLAC, DESY-PITZ and RAL. The hosing instability (HI) is a competing instability that may lead to beam breakup, and needs to be controlled over the long propagation distances required for SMI growth and saturation. In this work we show that the HI can be suppressed after SMI saturation in the linear wakefield excitation regime. SMI saturation before beam-break up can be achieved by seeding SMI, and as long as the initial bunch centroid displacements are within the initial bunch transverse size. The HI suppression occurs via a plasma analogue of the BNS damping in conventional accelerators.
* A. Caldwell et al, Nat. Physics Nat. Phys. 5, 363 (2009).

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WEPME021

Solid-state Pulsed Klystron Transmitters

klystron, high-voltage, operation, power-supply

2300

K. Schrock, C. Chipman, M.P.J. Gaudreau, B.E. Simpson
Diversified Technologies, Inc., Bedford, Massachusetts, USA

Funding: Lawrence Berkeley National Laboratory Daresbury Laboratory
Diversified Technologies, Inc. (DTI) is currently building and will deliver in early 2014 two solid-state pulsed klystron transmitters. Though not identical, the units are similar in design, and will be delivered to Lawrence Berkeley National Laboratory (LBNL) and Daresbury Laboratory in England. DTI’s goal across these two projects is to develop a complete package which can subsequently be marketed in the high peak power laboratory transmitter market. The modulator is a pulse transformer-coupled hybrid system, including ancillary klystron components (i.e., focus coil, socket) but not the actual klystron tube. Both systems employ a relatively simple modulator, consisting of an energy storage capacitor, a high voltage series switch, a step-up pulse transformer, and a passive pulse-flattening circuit. This arrangement gives an extremely flat pulse and allows the use of a moderate value of storage capacitor. The DTI switch can open or close as commanded, so the pulse width is adjusted by the gate pulse to the system.

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THOAB01

Recent Progress and Future Plan of Heavy-ion Radiotherapy Facility, HIMAC

ion, operation, synchrotron, heavy-ion

2812

K. Noda, T. Furukawa, Y. Hara, Y. Iwata, N. Kanematsu, K. Katagiri, A. Kitagawa, K. Mizushima, S. Mori, T. Murakami, M. Muramatsu, M. Nakao, A. Noda, S. Sato, T. Shirai, E. Takada, Y. Takei
NIRS, Chiba-shi, Japan

The first clinical trial with a carbon-ion beam generated from HIMAC was conducted in June 1994. Based on more than ten years of experience with HIMAC, a pilot facility of a standard carbon-ion radiotherapy facility in Japan, was constructed at Gunma University. Owing to the successfully operation of the pilot facility, Saga-HIMAT and i-ROCK in Kanagawa have been progressed. In addition, NIRS has developed the new treatment research project for the further development of radiotherapy with, based on the pencil-beam 3D scanning for both the static and moving targets. This treatment procedure has been successfully carried out with a pencil-beam 3D scanning since May 2011. Owing to the development of NIRS 3D scanning, the i-ROCK project decided to employ the NIRS 3D scanning. As a future plan, further, NIRS has developed a superconducting rotating gantry, and we are going to just start a study of a superconducting accelerator for the ion radiotherapy. The recent progress and the future plan of HIMAC for the heavy-ion cancer radiotherapy will be reported.

Slides THOAB01 [10.523 MB]

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THPRO043

Studies on the Application of the 3D Ellipsoidal Cathode Laser Pulses at PITZ

laser, booster, electron, emittance

2958

M. Khojoyan, M. Krasilnikov, F. Stephan
DESY Zeuthen, Zeuthen, Germany

Funding: The work is funded by the German federal Ministry of education and Research, project 05K10CHE “development and experimental test of a laser system for producing quasi 3D ellipsoidal laser pulses”.
The Photo Injector Test facility at DESY, Zeuthen Site (PITZ) characterizes and optimizes high brightness electron sources for FLASH and the European XFEL. At nominal conditions the electron bunches are created from a photocathode laser with flat-top temporal distribution and sharp rise and fall times. Beam dynamics simulations using a 3D ellipsoidal cathode laser shape yielded to a significant improvement of the electron beam quality compared to the traditionally used cylindrically shaped beams. The 3D ellipsoidal laser system is under development at the Institute of Applied Physics (IAP) and will be used at PITZ soon, to create high quality electron beams. The recent studies of electron beam simulations at PITZ have been devoted to the position optimization of the second accelerating cavity for the 3D ellipsoidal laser profile. Electron beam properties were compared for cylindrical and 3D ellipsoidal beams applying default and optimized booster positions. Beam tolerance studies revealed much better injector performance for the 3D ellipsoidal laser profile case with the optimized booster position. The outcome of such investigations is presented and discussed in this contribution.

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THPME015

Experimental Performance of an E×B Chopper System

rfq, proton, ion, dipole

3244

C. Wiesner, H. Dinter, M. Droba, O. Meusel, D. Noll, T. Nowottnick, O. Payir, U. Ratzinger, P.P. Schneider
IAP, Frankfurt am Main, Germany

Beam operation of an E×B chopper system has started in the Low-Energy Beam Transport (LEBT) section of the accelerator-driven neutron source FRANZ*. The chopper is designed for low-energy high-perveance beams and high repetition rates. It combines a static magnetic deflection field with a pulsed electric compensation field in a Wien filter-type E×B configuration**. Helium ions with 14 keV energy were successfully chopped at the required repetition rate of 257 kHz. The maximum chopped beam intensity of 3.5 mA, limited by the given test ion source, corresponds to a generalized perveance of 2.7·10^-3. For the design species and energy, 120 keV protons, this is equivalent to a beam current of 174 mA. Beam pulses with rise times of 120 ns, flat top lengths of 85 ns to 120 ns and Full Width at Half Maximum (FWHM) between 295 ns and 370 ns were experimentally achieved.
* U. Ratzinger et al., Proc. of IPAC2011, San Sebastián, Spain, WEPS040.
** C. Wiesner et al. Proc. of IPAC2012, New Orleans, LA., USA, THPPP074.

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THPME095

Length Measurement of High-brightness Electron Beam thanks to the 3-Phase Method

gun, electron, booster, laser

3459

T. Vinatier, C. Bruni, S. Chancé, P.M. Puzo
LAL, Orsay, France

The goal of 3-phase method is to determine the length of an electron beam without dedicated diagnostics by varying the measurement conditions of its energy spread, through a change in the RF phase of an accelerating structure. The originality here comes from the fact that it is applied on high-brightness electron beams of few MeV generated by RF photo-injectors. It allows testing the accuracy of 3-phase method, since the length to reconstruct is known as being that of the laser pulse generating the beam. It requires establishing the longitudinal transfer matrix of a RF photo-injector, which is difficult since the electron velocity vary from 0 to relativistic during its path*. The 3-phase method in RF photo-injector has been simulated by ASTRA and PARMELA codes, validating the principle of the method. First measurement has been done on PHIL accelerator at LAL, showing a good agreement with the expected length. I will then show results obtained at PITZ with a standing wave booster and a comparison with those coming from a Cerenkov detector. Finally, measurements at higher energy performed on the SOLEIL LINAC with travelling wave accelerating structures will be exposed.
* : K-J. Kim, “RF and Space Charge Effects in Laser-Driven RF Electron Guns”, Nucl. Instr. Meth., A275, 201 (1989)

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