IPAC2015 - List of Keywords (flattop)

Paper	Title	Other Keywords	Page
MOPWA040	Virtual Cavity Probe Generation using Calibrated Forward and Reflected Signals	cavity, coupling, controls, laser	200
	S. Pfeiffer, V. Ayvazyan, J. Branlard, L. Butkowski, H. Schlarb, Ch. Schmidt DESY, Hamburg, Germany R. Rybaniec Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland
	The European X-ray free electron laser requires a high-precision control of accelerating fields to ensure a stable photon generation. Its low level radio frequency system, based on the MicroTCA.4 standard, detects the probe, forward and reflected signals for each cavity. While the probe signal is used to control the accelerating fields, a combination of the forward and reflected signals can be used to compute a virtual probe, whose accuracy is comparable to the directly sampled probe. This requires the removal of cross-coupling effects between the forward and reflected signals. This paper presents the precise generation of a virtual probe using an extended method of least squares. The virtual probe can then be used for precise field control in case the probe signal is missing or corrupted. It can also be used to detect any deviation from the nominal probe profile.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPWA040
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TUPTY040	Comparison of Beam Sizes at the Collimator Locations from Measured Optics and Beam-based Collimator Alignment at the LHC	alignment, optics, injection, betatron	2101
	G. Valentino, R. Bruce, A. Langner, S. Redaelli, R. Tomás CERN, Geneva, Switzerland
	At the LHC, the collimation hierarchy is defined in units of the betatron beam size using the sizes at each collimator location. The beam size at a given collimator can be inferred from the gap measurement during beam-based alignment campaigns, when the collimator touches a reference beam halo defined with the primary collimators. On the other hand, the beta functions at each collimator are also measured as a part of the standard LHC optics validation. This paper presents a comparison of the beam size measurements at the collimator locations applying these two techniques for different machine configurations. This work aims at determining which is the most reliable method for setting the collimator gaps at the LHC.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY040
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TUPWI028	Varying Amplitude Raster Pattern for High Power Isotope Production Targets	target, isotope-production, experiment, proton	2298
	J.S. Kolski, J. Audia, H.T. Bach, Y.K. Batygin, J.T. Bradley III, M. Connors, J.W. Engle, E. Espinoza, E. Figueroa, M.J. Hall, M.P. Martinez, F.M. Nortier, D. Reass, W. Roybal, H.A. Watkins LANL, Los Alamos, New Mexico, USA
	The Isotope Production Facility (IPF) at LANSCE produces medical radionuclides strontium-82 and germanium-68 by bombarding rubidium chloride and gallium metal targets respectively with a 100 MeV proton beam, 230 uA average current. Rastering the proton beam is necessary to distribute beam power deposited as heat in the target and allow for higher average beam current for isotope production. We currently use a single circle raster pattern with constant amplitude and frequency. In this paper, we demonstrate two different varying amplitude raster patterns (concentric circle and spiral) to achieve uniform target coverage and expose more target volume to beam heating. In this proof-of-principle experiment, we compare beam spot uniformity measured by irradiating films and foils for both raster patterns.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWI028
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WEPWA061	High-Gradient Testing of Metallic Photonic Band-gap (PBG) and Disc-Loaded Waveguide (DLWG) Structures at 17 GHz	operation, coupling, diagnostics, wakefield	2643
	B.J. Munroe, M.A. Shapiro, R.J. Temkin, J.X. Zhang MIT/PSFC, Cambridge, Massachusetts, USA
	Funding: This work supported by the DOE, Office of High Energy Physics, Grant No. DE-SC0010075 Photonic Band-gap (PBG) structures continue to be a promising area of research for future accelerator structures. Previous experiments at 11 GHz have demonstrated that PBG structures can operate at high gradient and low breakdown probability, provided that pulsed heating is controlled. A metallic single-cell standing-wave PBG structure has been tested at 17 GHz at MIT to investigate how breakdown probability scales with frequency in these structures. A single-cell standing-wave disc-loaded waveguide (DLWG) was also tested at MIT as a reference structure. The PBG structure achieved greater than 90 MV/m gradient at 100 ns pulse length and a breakdown probability of 1.1 10-1 /pulse/m. The DLWG structure achieved 90 MV/m gradient at 100 ns pulse length and a breakdown probability of 1.2 10-1 /pulse/m, the same as the PBG structure within experimental error. These tests were conducted at the MIT structure test stand, and represent the first long-pulse breakdown testing of accelerator structures above X-Band.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPWA061
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WEPWA062	Design and High-Power Testing of a Hybrid Photonic Band-Gap (PBG) Accelerator Structure at 17 GHz	cavity, simulation, lattice, coupling	2646
	J.X. Zhang, A.M. Cook, B.J. Munroe, M.A. Shapiro, R.J. Temkin, H. Xu MIT/PSFC, Cambridge, Massachusetts, USA
	Funding: This work was supported by the U.S. Department of Energy, Office of High Energy Physics under Award Number DE-SC0010075. An overmoded hybrid Photonic Band Gap (HPBG) structure used as an accelerator cavity has been theoretically designed and high power tested at 17.1 GHz. The HPBG structure consists of a triangular lattice of dielectric (sapphire) and metallic (copper) rods. Due to the frequency selectivity, the hybrid PBG cavity can be operated in a TM02 mode. The maximum surface fields are on the triple point of the innermost row of the sapphire rods. The relatively high value of the surface fields resulted in a high breakdown rate (BDR) at a low gradient in the HPBG structure. Breakdown damage on the triple point edge and the metallization of copper onto the sapphire surface have been observed in the post-testing images. An improved HPBG design, that reduces the peak fields, has been developed. It will be built and tested in an effort to improve the HPBG performance.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPWA062
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WEPMA058	New Injection Bump Power Supply of the J-PARC RCS*	power-supply, injection, operation, timing	2908
	T. Takayanagi, N. Hayashi, K. Horino, M. Kinsho, K. Okabe, T. Ueno JAEA/J-PARC, Tokai-mura, Japan Y. Irie KEK, Ibaraki, Japan
	The new horizontal shift bump (SB) power supply for beam injection system of the J-PARC (Japan Proton Accelerator Research Complex) 3-GeV RCS (Rapid-Cycling Synchrotron) has been developed and manufactured. The injection energy was increased from 181 MeV to 400 MeV, and the power capacity of the new power supply was doubled. The power supply newly adopted a capacitor commutation method to form the trapezoid waveform pattern (bump waveform) by the IGBT (Insulated Gate Bipolar Transistor) switch. This paper reports characteristic, the problems and the user operation status about the new shift bump power supply.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPMA058
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WEPMN011	RF Modulation Studies on the S-Band Pulse Compressor	coupling, cavity, klystron, simulation	2937
	S. Shu Institute of High Energy Physics (IHEP), Chinese Academy of Sciences, Beijing, People's Republic of China F. Zhao IHEP, Beijing, People's Republic of China
	An S band SLED-type pulse compressor has been manufactured by IHEP to challenge the 100 MW maximum input power, which means the peak power around the coupling irises is about 500 MW at the phase reversal time. In order to deal with the breakdown problem, the dual side-wall coupling irises model was used. To further improve the reliability at very high power, RF phase modulation (PM) with flat-top output is considered. By using the CST Microwave Studio (MWS) transient solver, a new method was developed to simulate the time response of the pulse compressor. In addition, the theoretical and experimental results of the PM theory are also presented in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPMN011
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WEPMN031	Automated Quench Limit Test Procedure for Serial Production of XFEL RF Cavities	cavity, software, cryomodule, operation	2994
	K. Kasprzak, D. Konwisorz, K. Krzysik, S. Myalski, J. Świerbleski, K. Turaj, M. Wiencek, A. Zwozniak IFJ-PAN, Kraków, Poland D. Kostin, K.P. Przygoda DESY, Hamburg, Germany
	In the Accelerator Module Test Facility (AMTF) at DESY in Hamburg RF cavities and accelerating cryomodules are tested for the European X-ray Free Electron Laser (XFEL). Measurements are done by a team of physicists, engineers and technicians from The Henryk Niewodniczanski Institute of Nuclear Physics Polish Academy of Sciences in Kraków, Poland, as a part of Polish in-kind contribution to the XFEL. The testing procedures providing information about maximum available gradient and heat loads measurement are performed for the high gradients (up to 31MV/m). During these tests the cavity deformation caused by the Lorentz force is compensated by piezo (fast) tuners. For this purpose automated high level software was developed. This paper describes a method used to tune automatically the cavities during the RF tests. It was validated with the XFEL cryomodules. This improvement was implemented into the testing software and it is successfully used for testing of serial production cavities.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPMN031
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WEPMN032	Microphonic Disturbances Prediction and Compensation in Pulsed Superconducting Accelerators	cavity, controls, linac, operation	2997
	R. Rybaniec, L.J. Opalski Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland V. Ayvazyan, L. Butkowski, S. Pfeiffer, K.P. Przygoda, H. Schlarb, Ch. Schmidt DESY, Hamburg, Germany
	Accelerators are affected by the cavities detuning variation caused by external mechanical disturbances (microphonics). The paper presents microphonics estimation and prediction methods applicable for superconducting accelerators operating in pulsed mode. A mathematical model is built using the estimates of detuning during previous RF pulses. The model can be used for predictions of disturbances for the future time step and setup of the fast tuners accordingly. The proposed method was successfully verified with measurements conducted at the FLASH linac.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPMN032
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WEPHA035	Development of an IGBT Pulser for TPS LTB Kicker	kicker, injection, booster, operation	3191
	C.L. Chen, H.-P. Chang, Y.-S. Cheng, C.-S. Fann, K.T. Hsu, S.Y. Hsu, K.-K. Lin, K.L. Tsai NSRRC, Hsinchu, Taiwan
	The TPS LTB injection kicker was first commissioned using PFN pulser equipped with thyratron switch. Although its bench-testing results fulfilled the specifications but the performance was degraded due to unavoidable integration difficulty. After evaluating a couple of improvement options in hand, a pulser using IGBT switch was chosen for off-the-bench beneficial purpose. The upgraded pulser satisfies the overall specifications with comfortable margins. Some major performance parameters such as flattop and tail ringing are emphasized concerning their influence on beam injection. This report describes the field-testing result of this IGBT pulser.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPHA035
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WEPTY020	Design of a Marx-Topology Modulator for FNAL Linac	feedback, linac, cavity, proton	3306
	T.A. Butler, F.G. Garcia, M.R. Kufer, H. Pfeffer, D. Wolff Fermilab, Batavia, Illinois, USA
	The Fermilab Proton Improvement Plan (PIP) was formed in 2011 to address important and necessary upgrades to the Proton Source machines (Injector line, Linac and Booster). The goal is to increase the proton flux by doubling the Booster beam cycle rate while maintaining the same intensity per cycle, the same uptime, and the same residual activation on the accelerating structures. For Linac, the main focus within PIP is to address reliability. One of the main tasks is to replace the present hard-tube modulator used on the main 200MHz RF system. Plans to replace this high power system with a Marx-topology modulator, capable of providing the required waveform shaping to stable the accelerating gradient and compensate for beam loading, will be presented along with development data from the prototype unit.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPTY020
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WEPTY043	Short Pulse Marx Modulator	high-voltage, controls, network, collider	3370
	R.A. Phillips, M.P.J. Gaudreau, M.K. Kempkes, B.E. Simpson Diversified Technologies, Inc., Bedford, Massachusetts, USA J.A. Casey Rockfield Research Inc., Las Vegas, Nevada, USA
	Funding: DE-SC0004251 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, transformer-less 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) has completed development of 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 were 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.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPTY043
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Paper

Title

Other Keywords

Page

MOPWA040

Virtual Cavity Probe Generation using Calibrated Forward and Reflected Signals

cavity, coupling, controls, laser

200

S. Pfeiffer, V. Ayvazyan, J. Branlard, L. Butkowski, H. Schlarb, Ch. Schmidt
DESY, Hamburg, Germany
R. Rybaniec
Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland

The European X-ray free electron laser requires a high-precision control of accelerating fields to ensure a stable photon generation. Its low level radio frequency system, based on the MicroTCA.4 standard, detects the probe, forward and reflected signals for each cavity. While the probe signal is used to control the accelerating fields, a combination of the forward and reflected signals can be used to compute a virtual probe, whose accuracy is comparable to the directly sampled probe. This requires the removal of cross-coupling effects between the forward and reflected signals. This paper presents the precise generation of a virtual probe using an extended method of least squares. The virtual probe can then be used for precise field control in case the probe signal is missing or corrupted. It can also be used to detect any deviation from the nominal probe profile.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPWA040

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TUPTY040

Comparison of Beam Sizes at the Collimator Locations from Measured Optics and Beam-based Collimator Alignment at the LHC

alignment, optics, injection, betatron

2101

G. Valentino, R. Bruce, A. Langner, S. Redaelli, R. Tomás
CERN, Geneva, Switzerland

At the LHC, the collimation hierarchy is defined in units of the betatron beam size using the sizes at each collimator location. The beam size at a given collimator can be inferred from the gap measurement during beam-based alignment campaigns, when the collimator touches a reference beam halo defined with the primary collimators. On the other hand, the beta functions at each collimator are also measured as a part of the standard LHC optics validation. This paper presents a comparison of the beam size measurements at the collimator locations applying these two techniques for different machine configurations. This work aims at determining which is the most reliable method for setting the collimator gaps at the LHC.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPTY040

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TUPWI028

Varying Amplitude Raster Pattern for High Power Isotope Production Targets

target, isotope-production, experiment, proton

2298

J.S. Kolski, J. Audia, H.T. Bach, Y.K. Batygin, J.T. Bradley III, M. Connors, J.W. Engle, E. Espinoza, E. Figueroa, M.J. Hall, M.P. Martinez, F.M. Nortier, D. Reass, W. Roybal, H.A. Watkins
LANL, Los Alamos, New Mexico, USA

The Isotope Production Facility (IPF) at LANSCE produces medical radionuclides strontium-82 and germanium-68 by bombarding rubidium chloride and gallium metal targets respectively with a 100 MeV proton beam, 230 uA average current. Rastering the proton beam is necessary to distribute beam power deposited as heat in the target and allow for higher average beam current for isotope production. We currently use a single circle raster pattern with constant amplitude and frequency. In this paper, we demonstrate two different varying amplitude raster patterns (concentric circle and spiral) to achieve uniform target coverage and expose more target volume to beam heating. In this proof-of-principle experiment, we compare beam spot uniformity measured by irradiating films and foils for both raster patterns.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWI028

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WEPWA061

High-Gradient Testing of Metallic Photonic Band-gap (PBG) and Disc-Loaded Waveguide (DLWG) Structures at 17 GHz

operation, coupling, diagnostics, wakefield

2643

B.J. Munroe, M.A. Shapiro, R.J. Temkin, J.X. Zhang
MIT/PSFC, Cambridge, Massachusetts, USA

Funding: This work supported by the DOE, Office of High Energy Physics, Grant No. DE-SC0010075
Photonic Band-gap (PBG) structures continue to be a promising area of research for future accelerator structures. Previous experiments at 11 GHz have demonstrated that PBG structures can operate at high gradient and low breakdown probability, provided that pulsed heating is controlled. A metallic single-cell standing-wave PBG structure has been tested at 17 GHz at MIT to investigate how breakdown probability scales with frequency in these structures. A single-cell standing-wave disc-loaded waveguide (DLWG) was also tested at MIT as a reference structure. The PBG structure achieved greater than 90 MV/m gradient at 100 ns pulse length and a breakdown probability of 1.1 *10-1 /pulse/m. The DLWG structure achieved 90 MV/m gradient at 100 ns pulse length and a breakdown probability of 1.2 *10-1 /pulse/m, the same as the PBG structure within experimental error. These tests were conducted at the MIT structure test stand, and represent the first long-pulse breakdown testing of accelerator structures above X-Band.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPWA061

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WEPWA062

Design and High-Power Testing of a Hybrid Photonic Band-Gap (PBG) Accelerator Structure at 17 GHz

cavity, simulation, lattice, coupling

2646

J.X. Zhang, A.M. Cook, B.J. Munroe, M.A. Shapiro, R.J. Temkin, H. Xu
MIT/PSFC, Cambridge, Massachusetts, USA

Funding: This work was supported by the U.S. Department of Energy, Office of High Energy Physics under Award Number DE-SC0010075.
An overmoded hybrid Photonic Band Gap (HPBG) structure used as an accelerator cavity has been theoretically designed and high power tested at 17.1 GHz. The HPBG structure consists of a triangular lattice of dielectric (sapphire) and metallic (copper) rods. Due to the frequency selectivity, the hybrid PBG cavity can be operated in a TM02 mode. The maximum surface fields are on the triple point of the innermost row of the sapphire rods. The relatively high value of the surface fields resulted in a high breakdown rate (BDR) at a low gradient in the HPBG structure. Breakdown damage on the triple point edge and the metallization of copper onto the sapphire surface have been observed in the post-testing images. An improved HPBG design, that reduces the peak fields, has been developed. It will be built and tested in an effort to improve the HPBG performance.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPWA062

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

WEPMA058

New Injection Bump Power Supply of the J-PARC RCS*

power-supply, injection, operation, timing

2908

T. Takayanagi, N. Hayashi, K. Horino, M. Kinsho, K. Okabe, T. Ueno
JAEA/J-PARC, Tokai-mura, Japan
Y. Irie
KEK, Ibaraki, Japan

The new horizontal shift bump (SB) power supply for beam injection system of the J-PARC (Japan Proton Accelerator Research Complex) 3-GeV RCS (Rapid-Cycling Synchrotron) has been developed and manufactured. The injection energy was increased from 181 MeV to 400 MeV, and the power capacity of the new power supply was doubled. The power supply newly adopted a capacitor commutation method to form the trapezoid waveform pattern (bump waveform) by the IGBT (Insulated Gate Bipolar Transistor) switch. This paper reports characteristic, the problems and the user operation status about the new shift bump power supply.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPMA058

Export •

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

WEPMN011

RF Modulation Studies on the S-Band Pulse Compressor

coupling, cavity, klystron, simulation

2937

S. Shu
Institute of High Energy Physics (IHEP), Chinese Academy of Sciences, Beijing, People's Republic of China
F. Zhao
IHEP, Beijing, People's Republic of China

An S band SLED-type pulse compressor has been manufactured by IHEP to challenge the 100 MW maximum input power, which means the peak power around the coupling irises is about 500 MW at the phase reversal time. In order to deal with the breakdown problem, the dual side-wall coupling irises model was used. To further improve the reliability at very high power, RF phase modulation (PM) with flat-top output is considered. By using the CST Microwave Studio (MWS) transient solver, a new method was developed to simulate the time response of the pulse compressor. In addition, the theoretical and experimental results of the PM theory are also presented in this paper.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPMN011

Export •

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

WEPMN031

Automated Quench Limit Test Procedure for Serial Production of XFEL RF Cavities

cavity, software, cryomodule, operation

2994

K. Kasprzak, D. Konwisorz, K. Krzysik, S. Myalski, J. Świerbleski, K. Turaj, M. Wiencek, A. Zwozniak
IFJ-PAN, Kraków, Poland
D. Kostin, K.P. Przygoda
DESY, Hamburg, Germany

In the Accelerator Module Test Facility (AMTF) at DESY in Hamburg RF cavities and accelerating cryomodules are tested for the European X-ray Free Electron Laser (XFEL). Measurements are done by a team of physicists, engineers and technicians from The Henryk Niewodniczanski Institute of Nuclear Physics Polish Academy of Sciences in Kraków, Poland, as a part of Polish in-kind contribution to the XFEL. The testing procedures providing information about maximum available gradient and heat loads measurement are performed for the high gradients (up to 31MV/m). During these tests the cavity deformation caused by the Lorentz force is compensated by piezo (fast) tuners. For this purpose automated high level software was developed. This paper describes a method used to tune automatically the cavities during the RF tests. It was validated with the XFEL cryomodules. This improvement was implemented into the testing software and it is successfully used for testing of serial production cavities.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPMN031

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

WEPMN032

Microphonic Disturbances Prediction and Compensation in Pulsed Superconducting Accelerators

cavity, controls, linac, operation

2997

R. Rybaniec, L.J. Opalski
Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland
V. Ayvazyan, L. Butkowski, S. Pfeiffer, K.P. Przygoda, H. Schlarb, Ch. Schmidt
DESY, Hamburg, Germany

Accelerators are affected by the cavities detuning variation caused by external mechanical disturbances (microphonics). The paper presents microphonics estimation and prediction methods applicable for superconducting accelerators operating in pulsed mode. A mathematical model is built using the estimates of detuning during previous RF pulses. The model can be used for predictions of disturbances for the future time step and setup of the fast tuners accordingly. The proposed method was successfully verified with measurements conducted at the FLASH linac.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPMN032

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

WEPHA035

Development of an IGBT Pulser for TPS LTB Kicker

kicker, injection, booster, operation

3191

C.L. Chen, H.-P. Chang, Y.-S. Cheng, C.-S. Fann, K.T. Hsu, S.Y. Hsu, K.-K. Lin, K.L. Tsai
NSRRC, Hsinchu, Taiwan

The TPS LTB injection kicker was first commissioned using PFN pulser equipped with thyratron switch. Although its bench-testing results fulfilled the specifications but the performance was degraded due to unavoidable integration difficulty. After evaluating a couple of improvement options in hand, a pulser using IGBT switch was chosen for off-the-bench beneficial purpose. The upgraded pulser satisfies the overall specifications with comfortable margins. Some major performance parameters such as flattop and tail ringing are emphasized concerning their influence on beam injection. This report describes the field-testing result of this IGBT pulser.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPHA035

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

WEPTY020

Design of a Marx-Topology Modulator for FNAL Linac

feedback, linac, cavity, proton

3306

T.A. Butler, F.G. Garcia, M.R. Kufer, H. Pfeffer, D. Wolff
Fermilab, Batavia, Illinois, USA

The Fermilab Proton Improvement Plan (PIP) was formed in 2011 to address important and necessary upgrades to the Proton Source machines (Injector line, Linac and Booster). The goal is to increase the proton flux by doubling the Booster beam cycle rate while maintaining the same intensity per cycle, the same uptime, and the same residual activation on the accelerating structures. For Linac, the main focus within PIP is to address reliability. One of the main tasks is to replace the present hard-tube modulator used on the main 200MHz RF system. Plans to replace this high power system with a Marx-topology modulator, capable of providing the required waveform shaping to stable the accelerating gradient and compensate for beam loading, will be presented along with development data from the prototype unit.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPTY020

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

WEPTY043

Short Pulse Marx Modulator

high-voltage, controls, network, collider

3370

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

Funding: DE-SC0004251
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, transformer-less 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) has completed development of 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 were 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.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPTY043

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