IPAC2022 - Classification: MC7: Accelerator Technology / T08: RF Power Sources

Paper	Title	Page
TUPOST002	Upgrade of the 25 MW RF Station for the Linear Accelerator LINAC2 at ELSA	838
	D. Proft, K. Desch, D. Elsner, M.T. Switka ELSA, Bonn, Germany
	At the Electron Stretcher Facility ELSA in Bonn the first acceleration stage consists of a 3 GHz traveling wave linear accelerator. It was powered by a 25 MW pulsed high power klystron amplifier, which had been in use for the last thirty years. After a major failure and due to the lack of spare part availability the RF station was rebuilt. In addition to a new klystron including its high voltage tank, the new setup also consists of major upgrades of the infrastructure, the pulse forming network and the safety interlocks to satisfy the contemporary requirements. A new monitoring system consisting of multi-channel sampling ADCs allows for automatic pulse-by-pulse analysis of the klystron parameters and simultaneous evaluation of RF performance and stability. In this contribution we will present the new RF station setup, which has successfully been operating since the beginning of 2021 as well as the new monitoring capabilities.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST002
About •	Received ※ 04 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 03 July 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOST014	Sirius Storage Ring RF System Status Update	872
	A.P.B. Lima, D. Daminelli, M. Hoffmann Wallner, F.K.G. Hoshino LNLS, Campinas, Brazil I. Carvalho de Almeida, R.H.A. Farias CNPEM, Campinas, SP, Brazil
	Sirius’s nominal operation phase consists of two 500 MHz CESR-B type superconducting cavities, each being driven by four 65 kW solid-state amplifiers, and a passive superconducting third harmonic cavity. Currently a normal conducting 7-cell PETRA cavity is being used along with two 65 kW RF amplifiers and was recently able to achieve 100 mA stored current. The performance of the storage ring RF system and the updated installation plans update are presented and discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST014
About •	Received ※ 08 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 23 June 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOPT061	Status and Commissioning of the First X-Band RF Source of the TEX Facility	1148
	F. Cardelli, D. Alesini, M. Bellaveglia, S. Bini, M. Ceccarelli, C. Di Giulio, A. Falone, G. Franzini, A. Gallo, L. Piersanti, L. Sabbatini INFN/LNF, Frascati, Italy B. Buonomo, G. Catuscelli, R. Ceccarelli, A. Cecchinelli, R. Clementi, E. Di Pasquale, A. Liedl, D. Moriggi, G. Piermarini, S. Pioli, S. Quaglia, L.A. Rossi, M. Scampati, G. Scarselletta, S. Strabioli, S. Tocci, R. Zarlenga LNF-INFN, Frascati, Italy
	In 2021 started the commissioning of the TEX (Test stand for X-band) facility at the Frascati National laboratories of INFN. This facility has been founded in the framework of the LATINO (Laboratory in Advanced Technologies for INnOvation) project. The current facility layout includes an high power X-band (11.994 GHz) RF source, realized in collaboration with CERN, which will be used for validation and development of the X-band RF high gradient technology in view of the EuPRAXIA@SPARC_LAB project. The RF source is based on a CPI VKX8311 Klystron and a solid state ScandiNova k400 modulator to generate a maximum RF output power of 50 MW at 50 Hz, that will be mainly used for accelerating structure conditioning and waveguide components testing. In this paper the layout, the installation, commissioning and stability measurements of this source are described in detail. The test stand will be soon operative and ready to test the first X-band accelerating structure prototype.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOPT061
About •	Received ※ 08 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 10 July 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOTK049	Upgrade of ELSA’s Booster Synchrotron RF with a Solid State Power Amplifier	1327
	M.T. Switka, K. Desch, D. Elsner, F. Frommberger, P. Hänisch ELSA, Bonn, Germany
	The 1.6 GeV booster synchrotron of the ELSA facility at the University of Bonn uses a DESY-type RF resonator which has been driven by a conventional klystron amplifier since its early days in 1967. The setup was modified to serve the ELSA stretcher ring as booster synchrotron in 1987, but the RF infrastructure was barely altered. As repairs of the reliable, but antiquated RF source became foreseeingly impossible due to the lack of spare part availability, the replacement of the klystron amplifier chain in favour of a state-of-the-art solid state amplifier was carried out. We describe the replacement and the operation experience with the new RF power amplifier.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK049
About •	Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 17 June 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOTK051	Design Studies on a High-Power Wide-Band RF Combiner for Consolidation of the Driver Amplifier of the J-PARC RCS	1333
	H. Okita, K. Hara, K. Hasegawa, M. Nomura, T. Shimada, F. Tamura, M. Yamamoto KEK/JAEA, Ibaraki-Ken, Japan C. Ohmori, Y. Sugiyama, M. Yoshii KEK, Ibaraki, Japan M.M. Paoluzzi CERN, Meyrin, Switzerland
	A power upgrade of the existing 8 kW solid-state driver amplifier is required for the acceleration of high intensity proton beams in the J-PARC 3 GeV rapid cycling synchrotron (RCS). The development of a 25 kW amplifier with gallium nitride (GaN) HEMTs and based on 6.4 kW modules is ongoing. The combiner is a key component to achieve such a high output power over the wide bandwidth required for multi-harmonic rf operation. This paper presents a preliminary design of the combiner. The circuit simulation setup and results, including the realistic magnetic core characteristics and frequency response of the cables are reported.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK051
About •	Received ※ 18 May 2022 — Revised ※ 14 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 14 June 2022
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TUPOTK052	Influence of a Positive Grid Biasing on RF System in J-PARC RCS	1336
	M. Yamamoto, M. Nomura, H. Okita, T. Shimada, F. Tamura JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan K. Hara, K. Hasegawa, C. Ohmori, Y. Sugiyama, M. Yoshii KEK, Tokai, Ibaraki, Japan
	In order to accelerate a high intensity beam in the RCS, a large amplitude of the anode current is provided by a tube amplifier to compensate a heavy beam loading. Tetrode vacuum tubes are used in the RCS, and the control grid voltage enters into a positive region to feed such a large current. The positive grid biasing affects the waveform of the control grid voltage; it is deformed due to the induced control grid current under the condition of the multi-harmonic rf driving. Furthermore, the DC bias voltage drop on the control grid is observed because of the exceeding the ability for the control grid power supply. We describe the influence of the positive grid biasing in the RCS.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK052
About •	Received ※ 06 June 2022 — Revised ※ 17 June 2022 — Accepted ※ 22 June 2022 — Issue date ※ 24 June 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOTK053	Design Progress of High Efficiency Klystron for CEPC LINAC	1339
SUSPMF115	use link to see paper's listing under its alternate paper code
	Z.D. Zhang, Y.L. Chi, D. Dong, M. Iqbal, G. Pei, S.C. Wang, O. Xiao, S. Zhang, Z.S. Zhou IHEP, Beijing, People’s Republic of China S. Zhang, Z.D. Zhang UCAS, Beijing, People’s Republic of China
	The injector linear accelerator (LINAC) for the CEPC requires a higher efficiency klystron with 80MW output power than S band 65MW pulsed klys-tron currently operating in LINAC of BEPCII to reduce energy consumption and cost. The efficiency is ex-pected to improve from the currently observed 42% to more than 55% and output power will be improved from 65MW to more than 80MW with same operation voltage. In this paper, BAC bunching method is ap-plied for klystron efficiency improvement. The optimi-zation of the gun and solenoid parameters is complet-ed with 2-D code DGUN and then 3-D code CST. The preliminary design of the cavity parameters is also completed in 1-D disk model based AJDISK code and then further checked by 2-D code EMSYS. Finally, new klystron prototype will be fabricated in Chinese com-pany after design parameters are determined.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK053
About •	Received ※ 07 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 17 June 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOTK054	Solid State Amplifiers for Beam Test System of PAPS at IHEP	1342
	O. Xiao, Y.L. Chi, N. Gan, X.P. Li, Z.D. Zhang IHEP, People’s Republic of China
	Solid state amplifiers are being increasingly used as RF power sources in accelerators around the world. Two solid state amplifiers with different output power and frequen-cy have been applied in beam test system of PAPS at IHEP. A 10kW solid state amplifier operating at 1.3 GHz is used to feed a normal conducting buncher. A 650 MHz solid state amplifier with the output power of 150 kW is used to feed two 2-cell superconducting cavities. So far, the debugging and acceptance test of solid state amplifi-ers have been finished. During the beam test system commissioning and operation, all solid state amplifiers operate stably. In this paper, the specifications and high power test results of solid state amplifiers are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK054
About •	Received ※ 19 May 2022 — Revised ※ 10 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 06 July 2022
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TUPOTK055	One Year of Operation of the New Wideband RF System of the Proton Synchrotron Booster	1344
	G.G. Gnemmi, S. Energico, M. Haase, M.M. Paoluzzi, C. Rossi CERN, Meyrin, Switzerland
	Within the LHC Injectors Upgrade project, the PS Booster(PSB) has been upgraded. Both the injection (160 MeV) and extraction (2 GeV) energies have been increased, bringing also changes in the injection beam revolution frequency, the maximum revolution frequency, and the beam intensity. To meet the requirements of the High Luminosity LHC a new RF system has been designed, based on the wideband frequency characteristics of Finemet® Magnetic Alloy and solid-state amplifiers. The wideband frequency response (1 MHz to 18 MHz) covers all the required frequency schemes in the PSB, allowing multi-harmonics operation. The system is based on a cellular configuration in which each cell provides a fraction of the total RF voltage. The new RF system has been installed in 3 locations replacing the old systems. The installation has been performed during 2019/2020, while the commissioning started later in 2020 and relevant results for the physics have been already observed. This paper describes the new RF chain, the results achieved and the issues that occurred during this year of operation, together with the changes made to the system to improve performance and reliability.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK055
About •	Received ※ 02 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 28 June 2022
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TUPOTK057	Innovative Magnetron Power Sources for Superconducting RF (SRF) Accelerators	1348
	M.L. Neubauer, R.P. Johnson, R.R. Lentz, M. Popovic, T. Wynn Muons, Inc, Illinois, USA R.A. Rimmer, H. Wang JLab, Newport News, Virginia, USA
	Funding: Work supported by DOE SBIR grant # DE-SC0022484 A magnetron suitable for 1497 MHz klystron replacements at Jefferson Lab will be constructed and tested with our novel patented subcritical voltage operation methods to drive an SRF cavity. The critical areas of magnetron manufacturing and design affecting life-cycle costs that will be modeled for improvement include: Q_ext, filaments, magnetic field, vane design, and novel control of outgassing. The most immediate benefit of this project is to make SRF accelerator projects more affordable for NP and other users of SRF Linacs. One of the most attractive commercial applications for SRF accelerators is to drive subcritical nuclear reactors to burn Light Water Reactor Spent Nuclear Fuel (LWR SNF). A 1 GeV proton beam hitting an internal uranium spallation neutron target can produce over 30 neutrons for each incident proton to allow the reactor to operate far below criticality to generate electricity or process heat while reducing high-level waste disposal costs. This commercial application has the additional attribute of addressing climate change.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK057
About •	Received ※ 09 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 09 July 2022
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TUPOTK058	Development and Testing of High Power CW 1497 MHz Magnetron	1351
	M. Popovic, M.A. Cummings, A. Dudas, R.P. Johnson, R.R. Lentz, M.L. Neubauer, T. Wynn Muons, Inc, Illinois, USA T. Blassick, J.K. Wessel Richardson Electronics Ltd, Lafox, Illinois, USA K. Jordan, R.A. Rimmer, H. Wang JLab, Newport News, Virginia, USA
	Funding: Work supported by DOE NP STTR grant DE-SC0013203 We have designed, built, and tested a new magnetron tube that generates RF power at 1497 MHz. In the tests so far, the tube has produced CW 9 kW RF power, where the measured power is limited by the test equipment. The final goal is to use it to power superconducting (SC) cavities.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK058
About •	Received ※ 08 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 27 June 2022 — Issue date ※ 06 July 2022
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TUPOMS062	Overall Performance of 26 Power Stations at 400 kW - 352 MHz	1573
	C. Pasotti, A. Cuttin Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
	The spoke cavities section of the European Spallation Source (ESS) Linac will be powered by 26 Radio Frequency Power Stations (RFPSs). Each RFPS delivers 400 kW of Radio Frequency (RF) power at 352.21 MHz in pulsed mode at a repetition rate up to 14 Hz and a 5 % duty cycle, thanks to a twin tetrodes RF power sources integration. This equipment belongs to the Italian In-Kind Contributions (IKCs) to ESS. Elettra Sincrotrone Trieste S.C.p.A (Elettra) is responsible for the development, manufacturing and commissioning of the RFPSs and is managing the RFPS manufacturing contract awarded to European Science Solutions s.r.l (ESS-It). So far, 24 units have been delivered and, by mid 2022, the entire contribution, plus a complete spare unit, will be delivered to ESS. The overall performance of the RFPSs, the lessons learned, and the optimizations adopted along the manufacturing process and the difficulties that the COVID-19 pandemic has posed along the way are presented in this contribution.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS062
About •	Received ※ 07 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 04 July 2022
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FROXSP3	First Operation of a Klystron Fitted with a Superconducting MgB₂ Solenoid	3138
	N. Catalán Lasheras, M. Boronat, G. McMonagle, I. Syratchev CERN, Meyrin, Switzerland A. Baig, A. Castilla Cockcroft Institute, Lancaster University, Lancaster, United Kingdom T. Kimura, P.E. Kolda CPI, Palo Alto, California, USA S. Michizono, A. Yamamoto KEK, Ibaraki, Japan
	As part of the effort to reduce the energy consumption of large research facilities using accelerators, high efficiency klystrons are being developed by CERN. However, a large fraction of the wall-plug power required to operate these klystrons is used in the focusing magnetic elements around the klystron in the form of normal conducting solenoids. In 2019, a prototype solenoid made of MgB₂ was manufactured as a joint venture from CERN, Hitachi and KEK with the aim of reducing the power consumption by a factor ten using higher temperature superconductors. The characteristics of the magnet were measured upon manufacture and checked after the transport across the world. In 2020, the MgB₂ magnet was integrated around one of the klystrons in the X-band facility at CERN and put into operation in the beginning of 2021. We present in this paper the final performance of the klystron when fitted with the new SC solenoid and compare it with the standard normal conducting solenoid system.
	Slides FROXSP3 [4.661 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-FROXSP3
About •	Received ※ 11 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 16 June 2022
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Paper

Title

Page

Upgrade of the 25 MW RF Station for the Linear Accelerator LINAC2 at ELSA

838

D. Proft, K. Desch, D. Elsner, M.T. Switka
ELSA, Bonn, Germany

At the Electron Stretcher Facility ELSA in Bonn the first acceleration stage consists of a 3 GHz traveling wave linear accelerator. It was powered by a 25 MW pulsed high power klystron amplifier, which had been in use for the last thirty years. After a major failure and due to the lack of spare part availability the RF station was rebuilt. In addition to a new klystron including its high voltage tank, the new setup also consists of major upgrades of the infrastructure, the pulse forming network and the safety interlocks to satisfy the contemporary requirements. A new monitoring system consisting of multi-channel sampling ADCs allows for automatic pulse-by-pulse analysis of the klystron parameters and simultaneous evaluation of RF performance and stability. In this contribution we will present the new RF station setup, which has successfully been operating since the beginning of 2021 as well as the new monitoring capabilities.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST002

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Received ※ 04 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 03 July 2022

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TUPOST014

Sirius Storage Ring RF System Status Update

872

A.P.B. Lima, D. Daminelli, M. Hoffmann Wallner, F.K.G. Hoshino
LNLS, Campinas, Brazil
I. Carvalho de Almeida, R.H.A. Farias
CNPEM, Campinas, SP, Brazil

Sirius’s nominal operation phase consists of two 500 MHz CESR-B type superconducting cavities, each being driven by four 65 kW solid-state amplifiers, and a passive superconducting third harmonic cavity. Currently a normal conducting 7-cell PETRA cavity is being used along with two 65 kW RF amplifiers and was recently able to achieve 100 mA stored current. The performance of the storage ring RF system and the updated installation plans update are presented and discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST014

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Received ※ 08 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 23 June 2022

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TUPOPT061

Status and Commissioning of the First X-Band RF Source of the TEX Facility

1148

F. Cardelli, D. Alesini, M. Bellaveglia, S. Bini, M. Ceccarelli, C. Di Giulio, A. Falone, G. Franzini, A. Gallo, L. Piersanti, L. Sabbatini
INFN/LNF, Frascati, Italy
B. Buonomo, G. Catuscelli, R. Ceccarelli, A. Cecchinelli, R. Clementi, E. Di Pasquale, A. Liedl, D. Moriggi, G. Piermarini, S. Pioli, S. Quaglia, L.A. Rossi, M. Scampati, G. Scarselletta, S. Strabioli, S. Tocci, R. Zarlenga
LNF-INFN, Frascati, Italy

In 2021 started the commissioning of the TEX (Test stand for X-band) facility at the Frascati National laboratories of INFN. This facility has been founded in the framework of the LATINO (Laboratory in Advanced Technologies for INnOvation) project. The current facility layout includes an high power X-band (11.994 GHz) RF source, realized in collaboration with CERN, which will be used for validation and development of the X-band RF high gradient technology in view of the EuPRAXIA@SPARC_LAB project. The RF source is based on a CPI VKX8311 Klystron and a solid state ScandiNova k400 modulator to generate a maximum RF output power of 50 MW at 50 Hz, that will be mainly used for accelerating structure conditioning and waveguide components testing. In this paper the layout, the installation, commissioning and stability measurements of this source are described in detail. The test stand will be soon operative and ready to test the first X-band accelerating structure prototype.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOPT061

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Received ※ 08 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 10 July 2022

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TUPOTK049

Upgrade of ELSA’s Booster Synchrotron RF with a Solid State Power Amplifier

1327

M.T. Switka, K. Desch, D. Elsner, F. Frommberger, P. Hänisch
ELSA, Bonn, Germany

The 1.6 GeV booster synchrotron of the ELSA facility at the University of Bonn uses a DESY-type RF resonator which has been driven by a conventional klystron amplifier since its early days in 1967. The setup was modified to serve the ELSA stretcher ring as booster synchrotron in 1987, but the RF infrastructure was barely altered. As repairs of the reliable, but antiquated RF source became foreseeingly impossible due to the lack of spare part availability, the replacement of the klystron amplifier chain in favour of a state-of-the-art solid state amplifier was carried out. We describe the replacement and the operation experience with the new RF power amplifier.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK049

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Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 17 June 2022

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TUPOTK051

Design Studies on a High-Power Wide-Band RF Combiner for Consolidation of the Driver Amplifier of the J-PARC RCS

1333

H. Okita, K. Hara, K. Hasegawa, M. Nomura, T. Shimada, F. Tamura, M. Yamamoto
KEK/JAEA, Ibaraki-Ken, Japan
C. Ohmori, Y. Sugiyama, M. Yoshii
KEK, Ibaraki, Japan
M.M. Paoluzzi
CERN, Meyrin, Switzerland

A power upgrade of the existing 8 kW solid-state driver amplifier is required for the acceleration of high intensity proton beams in the J-PARC 3 GeV rapid cycling synchrotron (RCS). The development of a 25 kW amplifier with gallium nitride (GaN) HEMTs and based on 6.4 kW modules is ongoing. The combiner is a key component to achieve such a high output power over the wide bandwidth required for multi-harmonic rf operation. This paper presents a preliminary design of the combiner. The circuit simulation setup and results, including the realistic magnetic core characteristics and frequency response of the cables are reported.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK051

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Received ※ 18 May 2022 — Revised ※ 14 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 14 June 2022

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TUPOTK052

Influence of a Positive Grid Biasing on RF System in J-PARC RCS

1336

M. Yamamoto, M. Nomura, H. Okita, T. Shimada, F. Tamura
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
K. Hara, K. Hasegawa, C. Ohmori, Y. Sugiyama, M. Yoshii
KEK, Tokai, Ibaraki, Japan

In order to accelerate a high intensity beam in the RCS, a large amplitude of the anode current is provided by a tube amplifier to compensate a heavy beam loading. Tetrode vacuum tubes are used in the RCS, and the control grid voltage enters into a positive region to feed such a large current. The positive grid biasing affects the waveform of the control grid voltage; it is deformed due to the induced control grid current under the condition of the multi-harmonic rf driving. Furthermore, the DC bias voltage drop on the control grid is observed because of the exceeding the ability for the control grid power supply. We describe the influence of the positive grid biasing in the RCS.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK052

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Received ※ 06 June 2022 — Revised ※ 17 June 2022 — Accepted ※ 22 June 2022 — Issue date ※ 24 June 2022

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TUPOTK053

Design Progress of High Efficiency Klystron for CEPC LINAC

1339

SUSPMF115

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

Z.D. Zhang, Y.L. Chi, D. Dong, M. Iqbal, G. Pei, S.C. Wang, O. Xiao, S. Zhang, Z.S. Zhou
IHEP, Beijing, People’s Republic of China
S. Zhang, Z.D. Zhang
UCAS, Beijing, People’s Republic of China

The injector linear accelerator (LINAC) for the CEPC requires a higher efficiency klystron with 80MW output power than S band 65MW pulsed klys-tron currently operating in LINAC of BEPCII to reduce energy consumption and cost. The efficiency is ex-pected to improve from the currently observed 42% to more than 55% and output power will be improved from 65MW to more than 80MW with same operation voltage. In this paper, BAC bunching method is ap-plied for klystron efficiency improvement. The optimi-zation of the gun and solenoid parameters is complet-ed with 2-D code DGUN and then 3-D code CST. The preliminary design of the cavity parameters is also completed in 1-D disk model based AJDISK code and then further checked by 2-D code EMSYS. Finally, new klystron prototype will be fabricated in Chinese com-pany after design parameters are determined.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK053

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Received ※ 07 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 17 June 2022

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TUPOTK054

Solid State Amplifiers for Beam Test System of PAPS at IHEP

1342

O. Xiao, Y.L. Chi, N. Gan, X.P. Li, Z.D. Zhang
IHEP, People’s Republic of China

Solid state amplifiers are being increasingly used as RF power sources in accelerators around the world. Two solid state amplifiers with different output power and frequen-cy have been applied in beam test system of PAPS at IHEP. A 10kW solid state amplifier operating at 1.3 GHz is used to feed a normal conducting buncher. A 650 MHz solid state amplifier with the output power of 150 kW is used to feed two 2-cell superconducting cavities. So far, the debugging and acceptance test of solid state amplifi-ers have been finished. During the beam test system commissioning and operation, all solid state amplifiers operate stably. In this paper, the specifications and high power test results of solid state amplifiers are presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK054

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Received ※ 19 May 2022 — Revised ※ 10 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 06 July 2022

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TUPOTK055

One Year of Operation of the New Wideband RF System of the Proton Synchrotron Booster

1344

G.G. Gnemmi, S. Energico, M. Haase, M.M. Paoluzzi, C. Rossi
CERN, Meyrin, Switzerland

Within the LHC Injectors Upgrade project, the PS Booster(PSB) has been upgraded. Both the injection (160 MeV) and extraction (2 GeV) energies have been increased, bringing also changes in the injection beam revolution frequency, the maximum revolution frequency, and the beam intensity. To meet the requirements of the High Luminosity LHC a new RF system has been designed, based on the wideband frequency characteristics of Finemet® Magnetic Alloy and solid-state amplifiers. The wideband frequency response (1 MHz to 18 MHz) covers all the required frequency schemes in the PSB, allowing multi-harmonics operation. The system is based on a cellular configuration in which each cell provides a fraction of the total RF voltage. The new RF system has been installed in 3 locations replacing the old systems. The installation has been performed during 2019/2020, while the commissioning started later in 2020 and relevant results for the physics have been already observed. This paper describes the new RF chain, the results achieved and the issues that occurred during this year of operation, together with the changes made to the system to improve performance and reliability.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK055

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Received ※ 02 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 28 June 2022

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TUPOTK057

Innovative Magnetron Power Sources for Superconducting RF (SRF) Accelerators

1348

M.L. Neubauer, R.P. Johnson, R.R. Lentz, M. Popovic, T. Wynn
Muons, Inc, Illinois, USA
R.A. Rimmer, H. Wang
JLab, Newport News, Virginia, USA

Funding: Work supported by DOE SBIR grant # DE-SC0022484
A magnetron suitable for 1497 MHz klystron replacements at Jefferson Lab will be constructed and tested with our novel patented subcritical voltage operation methods to drive an SRF cavity. The critical areas of magnetron manufacturing and design affecting life-cycle costs that will be modeled for improvement include: Q_ext, filaments, magnetic field, vane design, and novel control of outgassing. The most immediate benefit of this project is to make SRF accelerator projects more affordable for NP and other users of SRF Linacs. One of the most attractive commercial applications for SRF accelerators is to drive subcritical nuclear reactors to burn Light Water Reactor Spent Nuclear Fuel (LWR SNF). A 1 GeV proton beam hitting an internal uranium spallation neutron target can produce over 30 neutrons for each incident proton to allow the reactor to operate far below criticality to generate electricity or process heat while reducing high-level waste disposal costs. This commercial application has the additional attribute of addressing climate change.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK057

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Received ※ 09 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 09 July 2022

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TUPOTK058

Development and Testing of High Power CW 1497 MHz Magnetron

1351

M. Popovic, M.A. Cummings, A. Dudas, R.P. Johnson, R.R. Lentz, M.L. Neubauer, T. Wynn
Muons, Inc, Illinois, USA
T. Blassick, J.K. Wessel
Richardson Electronics Ltd, Lafox, Illinois, USA
K. Jordan, R.A. Rimmer, H. Wang
JLab, Newport News, Virginia, USA

Funding: Work supported by DOE NP STTR grant DE-SC0013203
We have designed, built, and tested a new magnetron tube that generates RF power at 1497 MHz. In the tests so far, the tube has produced CW 9 kW RF power, where the measured power is limited by the test equipment. The final goal is to use it to power superconducting (SC) cavities.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK058

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Received ※ 08 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 27 June 2022 — Issue date ※ 06 July 2022

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TUPOMS062

Overall Performance of 26 Power Stations at 400 kW - 352 MHz

1573

C. Pasotti, A. Cuttin
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy

The spoke cavities section of the European Spallation Source (ESS) Linac will be powered by 26 Radio Frequency Power Stations (RFPSs). Each RFPS delivers 400 kW of Radio Frequency (RF) power at 352.21 MHz in pulsed mode at a repetition rate up to 14 Hz and a 5 % duty cycle, thanks to a twin tetrodes RF power sources integration. This equipment belongs to the Italian In-Kind Contributions (IKCs) to ESS. Elettra Sincrotrone Trieste S.C.p.A (Elettra) is responsible for the development, manufacturing and commissioning of the RFPSs and is managing the RFPS manufacturing contract awarded to European Science Solutions s.r.l (ESS-It). So far, 24 units have been delivered and, by mid 2022, the entire contribution, plus a complete spare unit, will be delivered to ESS. The overall performance of the RFPSs, the lessons learned, and the optimizations adopted along the manufacturing process and the difficulties that the COVID-19 pandemic has posed along the way are presented in this contribution.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS062

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Received ※ 07 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 04 July 2022

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FROXSP3

First Operation of a Klystron Fitted with a Superconducting MgB₂ Solenoid

3138

N. Catalán Lasheras, M. Boronat, G. McMonagle, I. Syratchev
CERN, Meyrin, Switzerland
A. Baig, A. Castilla
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
T. Kimura, P.E. Kolda
CPI, Palo Alto, California, USA
S. Michizono, A. Yamamoto
KEK, Ibaraki, Japan

As part of the effort to reduce the energy consumption of large research facilities using accelerators, high efficiency klystrons are being developed by CERN. However, a large fraction of the wall-plug power required to operate these klystrons is used in the focusing magnetic elements around the klystron in the form of normal conducting solenoids. In 2019, a prototype solenoid made of MgB₂ was manufactured as a joint venture from CERN, Hitachi and KEK with the aim of reducing the power consumption by a factor ten using higher temperature superconductors. The characteristics of the magnet were measured upon manufacture and checked after the transport across the world. In 2020, the MgB₂ magnet was integrated around one of the klystrons in the X-band facility at CERN and put into operation in the beginning of 2021. We present in this paper the final performance of the klystron when fitted with the new SC solenoid and compare it with the standard normal conducting solenoid system.

Slides FROXSP3 [4.661 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-FROXSP3

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Received ※ 11 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 16 June 2022

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