IPAC2019 - Classification: MC7: Accelerator Technology / T16 Pulsed Power Technology

Paper	Title	Page
THPRB026	A 300 mm Long Prototype Strip-Line Kicker for the Heps Injection System	3864
	L. Wang, J. Chen, L. Huo, P. Liu, H. Shi, X.L. Shi, G. Wang, N. Wang IHEP, Beijing, People’s Republic of China
	In the High Energy Photon Source (HEPS), the dynamic aperture of machine is not large enough for off-axis injec-tion for its baseline 7BA lattice design. So, a group of superfast kickers with about 12 ns pulse bottom width are needed for on-axis swap out injection scheme. The design about a couple sets of 300 mm long strip-line kickers is presented. Five kickers as a module are placed in a stain-less steel vacuum vessel to solve the problem of longitu-dinal space restriction in injection area. So far, the proto-type development of strip-line kicker was completed. The results of time-domain reflectometer (TDR) test and high voltage pulse test show that the strip-line kicker can meet the requirement of the HEPS.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB026
About •	paper received ※ 06 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019
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THPRB036	Development of Injection and Extraction Kickers for SuperKEKB Damping Ring	3890
	M. Tawada, M. Kikuchi, Y. Sakamoto, H. Someya KEK, Ibaraki, Japan K. Tenjin, A. Tokuchi Pulsed Power Japan Laboratory Ltd., Kusatsu-shi Shiga, Japan
	SuperKEKB is a double ring asymmetric collider to study the B meson physics, which is an upgrade project of KEKB. The 7 GeV electron (HER) and the 4 GeV positron ring (LER) collides at an interaction point. The positron beam produced by linac cannot meet the dynamic aperture restrictions of LER. Damping ring (DR) is required to reduce its injection emittance. Damping ring (DR) for SuperKEKB has two kicker magnets for the injection and the extraction, respectively. These kickers are required to meet the following specifications: (1) rise and fall time does not exceed 100 ns, (2) two bunches which are 96 ns apart must be kicked by single pulse, (3) the stability of peak current for the extraction kickers must be less than 0.1 %. Kicker magnets are designed as a conventional kicker with a ferrite core. The pulse shape is a double half sine for the two bunch injection. In order to achieve short rise time, a saturable inductance is used. The design and performance of kicker magnets and the power supplies are reported.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB036
About •	paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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THPRB041	Design a Precise Stability Controller for High Power Pulse Modulator Based on FPGA	3900
THPRB040	use link to see paper's listing under its alternate paper code
	Y.F. Liu, Z.H. Chen, M. Gu, J. Tong, Y. Wu, Q. Yuan, X.X. Zhou SINAP, Shanghai, People’s Republic of China
	Shanghai Soft X-ray Free Electron Laser (SXFEL) facility is under testing at Shanghai Institute of Applied Physics (SINAP), Chinese Academy of Sciences. The stability of RF system is one of the major factors to get great beam performance. It is mainly determined by klystron modulators power supply. The beam voltage of the LINAC klystron modulator, which is the pulsed power source of the RF amplifier, is directly affecting the RF amplitude and phase. This paper shows the suitable upgrade scheme of the modulator power supply and design considerations for the stability improvement of modulator power supply for Shanghai SXFEL. We present a real time feedback control system of LINAC pulse modulator to improve pulse to pulse amplitude stability. The feedback control system is based on the principle of embedded FPGA techniques. The control system consists of an embedded NIOS II processor, a High resolution ADC and an upper computer. The NIOS II processor manage on chip FIFO, ADC, IRQ, and Ethernet. The relevant experiments indicate that the feedback control strategy reaches required function. It is useful to improve the stability of existing modulator power supply.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB041
About •	paper received ※ 21 April 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019
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THPRB042	Stability Research Progress on High-power Pulse Modulator for SXFEL-UF	3904
	Q. Yuan, M. Gu, Y.F. Liu, J. Tong, Y. Wu SINAP, Shanghai, People’s Republic of China
	Funding: Supported by the National Natural Science Foundation of China(11675250) Abstract: SXFEL-UF(Shanghai Soft X-ray Free Electron Laser User Facility) under construction presently demands higher energy stability. Stability of pulse modulator feeding power for klystron plays an utmost important role in energy stability and occupy dominant factors in bringing influences in stability of RF power. Presently, stability of high-power pulse modulator of LINAC (Linear Accelerator) is on the level of 0.1% to 0.05% usually. In order to meet the higher stability requirements, it is very necessary for close-loop feedback control techniques instead of traditional open-loop to be applied in the modulator design. The stability controller adopts double control-loops techniques which feedback signals are respectively from PFN(Pulse Forming Network) and pulse transformer in oil tank. In addition, the paper also introduces recent progress on high stability CCPS research(Capacitor Charging Power Supply), which brings direct impact on the stability of modulator. In comparison with the former close-loop design, high stability CCPS design takes the overall modulator stability into full consideration. And the feedback control algorithm utilized to adjust PWMs for full bridge switch is implemented in the CCPS controller directly rather than modulator controller independent of CCPS. It is expected to obtain 0.01% stability by taking the above measures.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB042
About •	paper received ※ 06 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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THPRB071	Beam-Based Measurements on Two ±12.5 kV Inductive Adders, together with Striplines, for CLIC Damping Ring Extraction Kickers	3970
	J. Holma, M.J. Barnes, M. Carlà, N. Catalán Lasheras, Y. Papaphilippou CERN, Geneva, Switzerland U. Iriso, Z. Martí, F. Pérez, M. Pont ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
	The CLIC study is investigating the technical feasibil-ity of an electron-positron linear collider with high lumi-nosity and a nominal centre-of-mass energy of 3 TeV. Pre-damping rings and damping rings (DRs) will produce ultra-low emittance beam with high bunch charge. The DR kicker systems, each of which consists of a set of striplines and two inductive adders, must provide ex-tremely stable field pulses. The DR extraction kicker system is the most demanding: specifications require a field uniformity within ±0.01% and pulses up to 900 ns flattop duration, at ±12.5 kV and 309 A, with ripple and droop of not more than ±0.02 % (±2.5 V), with respect to a reference waveform. Two prototype inductive adders have been designed and built at CERN, and have been tested with prototype striplines installed in the storage ring of the ALBA Synchrotron Light Source, in Spain. The stability of the kicker system, including the modulators, has been evaluated from the beam-based measure-ments and is reported in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB071
About •	paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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THPRB073	Laboratory Measurements on Two ±12.5 kV Inductive Adders with ±0.02% Waveform Stability for CLIC Damping Ring Extraction Kickers	3978
	J. Holma, M.J. Barnes, A. Chmielinska CERN, Geneva, Switzerland M. Pont ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
	The CLIC study is investigating the technical feasibil-ity of an electron-positron collider with high luminosity and a nominal centre-of-mass energy of 3 TeV. Pre-damping rings and damping rings (DRs) will produce ultra-low emittance beam with high bunch charge. The DR kicker systems must provide extremely stable field pulses to avoid beam emittance increase. Each DR extrac-tion kicker system consists of a set of striplines and two pulse modulators. Specifications for this system require that the modulator produce pulses of 900 ns flattop dura-tion, ±12.5 kV and 305 A, with ripple and droop of not more than ±0.02 % (±2.5 V) with respect to a reference waveform. Inductive adder topology has been chosen for the pulse modulators. Two full-scale, 20-layer, 12.5 kV prototype inductive adders have been designed, built and tested at CERN. This paper presents the measurements of the stability of these adders for two different waveforms: a flat-top waveform and a controlled decay waveform, the latter of which is required to generate flat-top total field for the CLIC DR extraction stripline kicker.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB073
About •	paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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THPRB074	Studies Towards the New Beam Screen System of the LHC Injection Kicker Magnet for HL-LHC Operation	3982
	V. Vlachodimitropoulos, M.J. Barnes, A. Chmielinska, L. Ducimetière, L. Vega Cid, W.J.M. Weterings CERN, Geneva, Switzerland A. Chmielinska EPFL, Lausanne, Switzerland L. Vega Cid ETSII UPM, Madrid, Spain
	Although no heating issues were observed in the Large Hadron Collider’s (LHC) injection kicker magnets (MKIs) during Run 2, simulations suggest that for operation with the high intensity beams of the High Luminosity LHC (HL-LHC) project, the magnet’s ferrite yokes will reach their Curie temperature, thus leading to long turnaround times before a new beam can be safely injected into the machine. To safely enter the HL-LHC era, a campaign to redesign the kicker’s beam screen was launched. An improved beam-screen has already been implemented in an upgraded MKI, that was installed in the LHC tunnel in the Year End Technical Stop (YETS) 17/18, and has been successfully tested during 2018 operation. However, the improved design alone is not expected to be enough for HL-LHC operation, and further modifications are required. In this work, the approach to the design from an electromagnetic point of view is presented and different considered options are reported, emphasising the final design of the new beam screen system that is currently being implemented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB074
About •	paper received ※ 14 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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THPRB075	Transverse Impedance Measurements and Simulations of the LHC Injection Kicker Magnet	3986
	V. Vlachodimitropoulos, M.J. Barnes, A. Chmielinska, L. Ducimetière CERN, Geneva, Switzerland A. Chmielinska EPFL, Lausanne, Switzerland
	Kicker magnets contribute significantly to the total impedance budget of many accelerators. Of particular interest, from a beam stability point of view, is the transverse beam coupling impedance (TBCI) that is used to determine intensity limitations of a machine. Until recently, no conclusive TBCI data for the Large Hadron Collider (LHC) injection kicker magnets (MKIs) was available. However, in view of the upgrade of the MKIs for the High-Luminosity LHC (HL-LHC) project, the TBCI of the existing design needed to be estimated to be used as reference for an upgraded version. To that end, electromagnetic simulations were carried out to determine the dipolar and quadrupolar components of the TBCI in the two transverse planes. To validate the simulations, test bench measurements were performed using standard RF measurement techniques. In the present work, the results from TBCI simulations and measurements are reported and compared. Detailed descriptions of the methods and techniques used as well as the realization of the experimental set-up are also given.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB075
About •	paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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THPRB078	Performance Validation of the Existing and Upgraded PS Injection Kicker	3994
	A. Ferrero Colomo, N. Ayala, A. Chmielinska, V. Forte, M.A. Fraser, T. Kramer, L. Sermeus CERN, Geneva, Switzerland
	The CERN PS injection kicker KFA45 will be upgraded in the framework of the LHC Injector Upgrade (LIU) project to allow for injection of 2 GeV proton beams. This paper summarizes the recent efforts to validate beam based waveform measurements, Pspice simulations and current waveform measurements by direct magnetic field measurements in the aperture of the existing system. The magnetic probe, associated measurement hardware design and measurements results are discussed. The paper concludes with a performance comparison and an outlook to future waveform tuning possibilities.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB078
About •	paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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THPRB079	DC Testing and Phase Resolved Partial Discharge Measurements of the New Trigger Transformers for the LHC Beam Dump Kickers	3998
	T. Stadlbauer, A. Chmielinska, L. Ducimetière, D. Kontelis, T. Kramer, V. Senaj CERN, Geneva, Switzerland
	During LS2 the LHC beam dump kicker pulse generators will be subject to a substantial consolidation program. One major part is the replacement of the existing GTO stack trigger transformer by a new more performant one. The transformer is assembled, moulded and tested in-house. Part of the validation procedure are standard DC tests and subsequent discharge monitoring as well as newly introduced phase resolved partial discharge measurements. This paper briefly highlights the trigger transformer parameters and construction and outlines in detail the testing and partial discharge measurements. It concludes with a comparison and analysis of the results of the different measurement techniques.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB079
About •	paper received ※ 14 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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THPRB105	ESS Klystron Production Test Stand	4074
	I. Roth, M.P.J. Gaudreau, M.K. Kempkes, N. Silverman, R.E. Simpson Diversified Technologies, Inc., Bedford, Massachusetts, USA
	Diversified Technologies, Inc. (DTI) has delivered a new long-pulse modulator klystron test stand to Communication and Power Industries (CPI) in Palo Alto, CA for full power testing of production VKP-8292A klystrons for the European Spallation Source (ESS). This test stand was built using hardware and designs from an earlier SBIR effort for the US Department of Energy, with modifications to support ESS requirements and klystron testing operation. Earlier versions of this design are in use at IPN Orsay and CEA Saclay in France to test RF components for ESS. This new klystron test stand allows testing of klystrons at the full ESS specifications: 100 kV, 50 A, 3.5 ms pulse, 14 Hz,. This design is based on a (patent pending) non-dissipative regulator that compensates for the capacitor droop voltage (~20%) during the pulse. This allows a much smaller capacitor than would nominally be required for the long ESS pulse, eliminating the need for larger, more expensive capacitor bank. This test stand will speed delivery of ESS klystrons, and similar, long pulse, high power klystrons at CPI.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB105
About •	paper received ※ 19 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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FRXXPLM3	Development of a Pulsed Power Supply Utilizing 13 kV Class SiC-MOSFET	4364
	K. Okamura, F. Naito, K. Takayama KEK, Ibaraki, Japan K. Fukuda, H. Kitai, K. Sakamoto AIST, Tsukuba, Ibaraki, Japan T. Kaito Chiba Institute of Technology, Narashino, Chiba, Japan D. Kumamoto Nagaoka University of Technology, Nagaoka, Niigata, Japan S. Lim, A. Tokuchi Pulsed Power Japan Laboratory Ltd., Kusatsu-shi Shiga, Japan
	Funding: A part of this work has been implemented under a joint research project of Tsukuba Power Electronics Constellation (TPEC). To resolve the drawback of conventional thyratron switches, development of a semiconductor high voltage switch utilizing a 13 kV class SiC-MOSFET developed by Tsukuba Power Electronics Constellations (TPEC) is proceeding. At first, the device evaluation test was carried out with a resistive load circuit. With the conditions of drain voltage of 10 kV and load resistance of 1 kΩ, turn on loss Eon, turn off loss Eoff, rise time Tr and fall time Tf were 1.7 mJ, 1.1 mJ, 64 ns, and 75 ns, respectively. As to gate charge characteristics, required electric charge to increase gate source voltage from 0 V to 20 V was about 80 nC. Thereafter, the 2s-12p switch array was designed and assembled, where 12 MOSFETs are equally aligned on a circle shaped circuit board and two circuit boards are stacked in series. A 14 kV-490 A-5 us pulse with a rise time of 430 ns in the long pulse mode and a 18 kV-318 A-1 us pulse with a rise time of 289 ns in the short pulse mode were successfully demonstrated. This switch will be installed as a turn-off switch for the injec-tion ES kicker in the KEK-DA.
	Slides FRXXPLM3 [5.088 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-FRXXPLM3
About •	paper received ※ 15 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019
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Paper

Title

Page

A 300 mm Long Prototype Strip-Line Kicker for the Heps Injection System

3864

L. Wang, J. Chen, L. Huo, P. Liu, H. Shi, X.L. Shi, G. Wang, N. Wang
IHEP, Beijing, People’s Republic of China

In the High Energy Photon Source (HEPS), the dynamic aperture of machine is not large enough for off-axis injec-tion for its baseline 7BA lattice design. So, a group of superfast kickers with about 12 ns pulse bottom width are needed for on-axis swap out injection scheme. The design about a couple sets of 300 mm long strip-line kickers is presented. Five kickers as a module are placed in a stain-less steel vacuum vessel to solve the problem of longitu-dinal space restriction in injection area. So far, the proto-type development of strip-line kicker was completed. The results of time-domain reflectometer (TDR) test and high voltage pulse test show that the strip-line kicker can meet the requirement of the HEPS.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB026

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paper received ※ 06 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019

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THPRB036

Development of Injection and Extraction Kickers for SuperKEKB Damping Ring

3890

M. Tawada, M. Kikuchi, Y. Sakamoto, H. Someya
KEK, Ibaraki, Japan
K. Tenjin, A. Tokuchi
Pulsed Power Japan Laboratory Ltd., Kusatsu-shi Shiga, Japan

SuperKEKB is a double ring asymmetric collider to study the B meson physics, which is an upgrade project of KEKB. The 7 GeV electron (HER) and the 4 GeV positron ring (LER) collides at an interaction point. The positron beam produced by linac cannot meet the dynamic aperture restrictions of LER. Damping ring (DR) is required to reduce its injection emittance. Damping ring (DR) for SuperKEKB has two kicker magnets for the injection and the extraction, respectively. These kickers are required to meet the following specifications: (1) rise and fall time does not exceed 100 ns, (2) two bunches which are 96 ns apart must be kicked by single pulse, (3) the stability of peak current for the extraction kickers must be less than 0.1 %. Kicker magnets are designed as a conventional kicker with a ferrite core. The pulse shape is a double half sine for the two bunch injection. In order to achieve short rise time, a saturable inductance is used. The design and performance of kicker magnets and the power supplies are reported.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB036

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paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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THPRB041

Design a Precise Stability Controller for High Power Pulse Modulator Based on FPGA

3900

THPRB040

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

Y.F. Liu, Z.H. Chen, M. Gu, J. Tong, Y. Wu, Q. Yuan, X.X. Zhou
SINAP, Shanghai, People’s Republic of China

Shanghai Soft X-ray Free Electron Laser (SXFEL) facility is under testing at Shanghai Institute of Applied Physics (SINAP), Chinese Academy of Sciences. The stability of RF system is one of the major factors to get great beam performance. It is mainly determined by klystron modulators power supply. The beam voltage of the LINAC klystron modulator, which is the pulsed power source of the RF amplifier, is directly affecting the RF amplitude and phase. This paper shows the suitable upgrade scheme of the modulator power supply and design considerations for the stability improvement of modulator power supply for Shanghai SXFEL. We present a real time feedback control system of LINAC pulse modulator to improve pulse to pulse amplitude stability. The feedback control system is based on the principle of embedded FPGA techniques. The control system consists of an embedded NIOS II processor, a High resolution ADC and an upper computer. The NIOS II processor manage on chip FIFO, ADC, IRQ, and Ethernet. The relevant experiments indicate that the feedback control strategy reaches required function. It is useful to improve the stability of existing modulator power supply.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB041

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paper received ※ 21 April 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019

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THPRB042

Stability Research Progress on High-power Pulse Modulator for SXFEL-UF

3904

Q. Yuan, M. Gu, Y.F. Liu, J. Tong, Y. Wu
SINAP, Shanghai, People’s Republic of China

Funding: Supported by the National Natural Science Foundation of China(11675250)
Abstract: SXFEL-UF(Shanghai Soft X-ray Free Electron Laser User Facility) under construction presently demands higher energy stability. Stability of pulse modulator feeding power for klystron plays an utmost important role in energy stability and occupy dominant factors in bringing influences in stability of RF power. Presently, stability of high-power pulse modulator of LINAC (Linear Accelerator) is on the level of 0.1% to 0.05% usually. In order to meet the higher stability requirements, it is very necessary for close-loop feedback control techniques instead of traditional open-loop to be applied in the modulator design. The stability controller adopts double control-loops techniques which feedback signals are respectively from PFN(Pulse Forming Network) and pulse transformer in oil tank. In addition, the paper also introduces recent progress on high stability CCPS research(Capacitor Charging Power Supply), which brings direct impact on the stability of modulator. In comparison with the former close-loop design, high stability CCPS design takes the overall modulator stability into full consideration. And the feedback control algorithm utilized to adjust PWMs for full bridge switch is implemented in the CCPS controller directly rather than modulator controller independent of CCPS. It is expected to obtain 0.01% stability by taking the above measures.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB042

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paper received ※ 06 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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THPRB071

Beam-Based Measurements on Two ±12.5 kV Inductive Adders, together with Striplines, for CLIC Damping Ring Extraction Kickers

3970

J. Holma, M.J. Barnes, M. Carlà, N. Catalán Lasheras, Y. Papaphilippou
CERN, Geneva, Switzerland
U. Iriso, Z. Martí, F. Pérez, M. Pont
ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain

The CLIC study is investigating the technical feasibil-ity of an electron-positron linear collider with high lumi-nosity and a nominal centre-of-mass energy of 3 TeV. Pre-damping rings and damping rings (DRs) will produce ultra-low emittance beam with high bunch charge. The DR kicker systems, each of which consists of a set of striplines and two inductive adders, must provide ex-tremely stable field pulses. The DR extraction kicker system is the most demanding: specifications require a field uniformity within ±0.01% and pulses up to 900 ns flattop duration, at ±12.5 kV and 309 A, with ripple and droop of not more than ±0.02 % (±2.5 V), with respect to a reference waveform. Two prototype inductive adders have been designed and built at CERN, and have been tested with prototype striplines installed in the storage ring of the ALBA Synchrotron Light Source, in Spain. The stability of the kicker system, including the modulators, has been evaluated from the beam-based measure-ments and is reported in this paper.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB071

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paper received ※ 15 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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THPRB073

Laboratory Measurements on Two ±12.5 kV Inductive Adders with ±0.02% Waveform Stability for CLIC Damping Ring Extraction Kickers

3978

J. Holma, M.J. Barnes, A. Chmielinska
CERN, Geneva, Switzerland
M. Pont
ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain

The CLIC study is investigating the technical feasibil-ity of an electron-positron collider with high luminosity and a nominal centre-of-mass energy of 3 TeV. Pre-damping rings and damping rings (DRs) will produce ultra-low emittance beam with high bunch charge. The DR kicker systems must provide extremely stable field pulses to avoid beam emittance increase. Each DR extrac-tion kicker system consists of a set of striplines and two pulse modulators. Specifications for this system require that the modulator produce pulses of 900 ns flattop dura-tion, ±12.5 kV and 305 A, with ripple and droop of not more than ±0.02 % (±2.5 V) with respect to a reference waveform. Inductive adder topology has been chosen for the pulse modulators. Two full-scale, 20-layer, 12.5 kV prototype inductive adders have been designed, built and tested at CERN. This paper presents the measurements of the stability of these adders for two different waveforms: a flat-top waveform and a controlled decay waveform, the latter of which is required to generate flat-top total field for the CLIC DR extraction stripline kicker.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB073

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paper received ※ 15 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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THPRB074

Studies Towards the New Beam Screen System of the LHC Injection Kicker Magnet for HL-LHC Operation

3982

V. Vlachodimitropoulos, M.J. Barnes, A. Chmielinska, L. Ducimetière, L. Vega Cid, W.J.M. Weterings
CERN, Geneva, Switzerland
A. Chmielinska
EPFL, Lausanne, Switzerland
L. Vega Cid
ETSII UPM, Madrid, Spain

Although no heating issues were observed in the Large Hadron Collider’s (LHC) injection kicker magnets (MKIs) during Run 2, simulations suggest that for operation with the high intensity beams of the High Luminosity LHC (HL-LHC) project, the magnet’s ferrite yokes will reach their Curie temperature, thus leading to long turnaround times before a new beam can be safely injected into the machine. To safely enter the HL-LHC era, a campaign to redesign the kicker’s beam screen was launched. An improved beam-screen has already been implemented in an upgraded MKI, that was installed in the LHC tunnel in the Year End Technical Stop (YETS) 17/18, and has been successfully tested during 2018 operation. However, the improved design alone is not expected to be enough for HL-LHC operation, and further modifications are required. In this work, the approach to the design from an electromagnetic point of view is presented and different considered options are reported, emphasising the final design of the new beam screen system that is currently being implemented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB074

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paper received ※ 14 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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THPRB075

Transverse Impedance Measurements and Simulations of the LHC Injection Kicker Magnet

3986

V. Vlachodimitropoulos, M.J. Barnes, A. Chmielinska, L. Ducimetière
CERN, Geneva, Switzerland
A. Chmielinska
EPFL, Lausanne, Switzerland

Kicker magnets contribute significantly to the total impedance budget of many accelerators. Of particular interest, from a beam stability point of view, is the transverse beam coupling impedance (TBCI) that is used to determine intensity limitations of a machine. Until recently, no conclusive TBCI data for the Large Hadron Collider (LHC) injection kicker magnets (MKIs) was available. However, in view of the upgrade of the MKIs for the High-Luminosity LHC (HL-LHC) project, the TBCI of the existing design needed to be estimated to be used as reference for an upgraded version. To that end, electromagnetic simulations were carried out to determine the dipolar and quadrupolar components of the TBCI in the two transverse planes. To validate the simulations, test bench measurements were performed using standard RF measurement techniques. In the present work, the results from TBCI simulations and measurements are reported and compared. Detailed descriptions of the methods and techniques used as well as the realization of the experimental set-up are also given.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB075

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paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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THPRB078

Performance Validation of the Existing and Upgraded PS Injection Kicker

3994

A. Ferrero Colomo, N. Ayala, A. Chmielinska, V. Forte, M.A. Fraser, T. Kramer, L. Sermeus
CERN, Geneva, Switzerland

The CERN PS injection kicker KFA45 will be upgraded in the framework of the LHC Injector Upgrade (LIU) project to allow for injection of 2 GeV proton beams. This paper summarizes the recent efforts to validate beam based waveform measurements, Pspice simulations and current waveform measurements by direct magnetic field measurements in the aperture of the existing system. The magnetic probe, associated measurement hardware design and measurements results are discussed. The paper concludes with a performance comparison and an outlook to future waveform tuning possibilities.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB078

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paper received ※ 14 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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THPRB079

DC Testing and Phase Resolved Partial Discharge Measurements of the New Trigger Transformers for the LHC Beam Dump Kickers

3998

T. Stadlbauer, A. Chmielinska, L. Ducimetière, D. Kontelis, T. Kramer, V. Senaj
CERN, Geneva, Switzerland

During LS2 the LHC beam dump kicker pulse generators will be subject to a substantial consolidation program. One major part is the replacement of the existing GTO stack trigger transformer by a new more performant one. The transformer is assembled, moulded and tested in-house. Part of the validation procedure are standard DC tests and subsequent discharge monitoring as well as newly introduced phase resolved partial discharge measurements. This paper briefly highlights the trigger transformer parameters and construction and outlines in detail the testing and partial discharge measurements. It concludes with a comparison and analysis of the results of the different measurement techniques.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB079

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paper received ※ 14 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

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THPRB105

ESS Klystron Production Test Stand

4074

I. Roth, M.P.J. Gaudreau, M.K. Kempkes, N. Silverman, R.E. Simpson
Diversified Technologies, Inc., Bedford, Massachusetts, USA

Diversified Technologies, Inc. (DTI) has delivered a new long-pulse modulator klystron test stand to Communication and Power Industries (CPI) in Palo Alto, CA for full power testing of production VKP-8292A klystrons for the European Spallation Source (ESS). This test stand was built using hardware and designs from an earlier SBIR effort for the US Department of Energy, with modifications to support ESS requirements and klystron testing operation. Earlier versions of this design are in use at IPN Orsay and CEA Saclay in France to test RF components for ESS. This new klystron test stand allows testing of klystrons at the full ESS specifications: 100 kV, 50 A, 3.5 ms pulse, 14 Hz,. This design is based on a (patent pending) non-dissipative regulator that compensates for the capacitor droop voltage (~20%) during the pulse. This allows a much smaller capacitor than would nominally be required for the long ESS pulse, eliminating the need for larger, more expensive capacitor bank. This test stand will speed delivery of ESS klystrons, and similar, long pulse, high power klystrons at CPI.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB105

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paper received ※ 19 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

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FRXXPLM3

Development of a Pulsed Power Supply Utilizing 13 kV Class SiC-MOSFET

4364

K. Okamura, F. Naito, K. Takayama
KEK, Ibaraki, Japan
K. Fukuda, H. Kitai, K. Sakamoto
AIST, Tsukuba, Ibaraki, Japan
T. Kaito
Chiba Institute of Technology, Narashino, Chiba, Japan
D. Kumamoto
Nagaoka University of Technology, Nagaoka, Niigata, Japan
S. Lim, A. Tokuchi
Pulsed Power Japan Laboratory Ltd., Kusatsu-shi Shiga, Japan

Funding: A part of this work has been implemented under a joint research project of Tsukuba Power Electronics Constellation (TPEC).
To resolve the drawback of conventional thyratron switches, development of a semiconductor high voltage switch utilizing a 13 kV class SiC-MOSFET developed by Tsukuba Power Electronics Constellations (TPEC) is proceeding. At first, the device evaluation test was carried out with a resistive load circuit. With the conditions of drain voltage of 10 kV and load resistance of 1 kΩ, turn on loss Eon, turn off loss Eoff, rise time Tr and fall time Tf were 1.7 mJ, 1.1 mJ, 64 ns, and 75 ns, respectively. As to gate charge characteristics, required electric charge to increase gate source voltage from 0 V to 20 V was about 80 nC. Thereafter, the 2s-12p switch array was designed and assembled, where 12 MOSFETs are equally aligned on a circle shaped circuit board and two circuit boards are stacked in series. A 14 kV-490 A-5 us pulse with a rise time of 430 ns in the long pulse mode and a 18 kV-318 A-1 us pulse with a rise time of 289 ns in the short pulse mode were successfully demonstrated. This switch will be installed as a turn-off switch for the injec-tion ES kicker in the KEK-DA.

Slides FRXXPLM3 [5.088 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-FRXXPLM3

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paper received ※ 15 May 2019 paper accepted ※ 21 May 2019 issue date ※ 21 June 2019

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