IPAC2022 - List of Keywords (klystron)

Paper	Title	Other Keywords	Page
MOPOMS022	Studies of a Ka-Band High Power Klystron Amplifier at INFN-LNF	cavity, electron, gun, focusing	683
	M. Behtouei, L. Faillace, A. Mostacci, B. Spataro LNF-INFN, Frascati, Italy F. Bosco, M. Carillo, M. Migliorati, A. Mostacci, L. Palumbo Sapienza University of Rome, Rome, Italy F. Di Paolo, S. Fantauzzi, A. Leggieri, F. Marrese, L. Valletti Università degli Studi di Roma "Tor Vergata", Roma, Italy G. Torrisi INFN/LNS, Catania, Italy
	In the framework of the Compact Light XLS project, a Ka-band linearizer with electric field ranging from 100 to 150 MV/m is requested. In order to feed this structure, a proper Ka-band high power klystron amplifier with a high efficiency is needed. This paper reports a possible solution for a klystron amplifier operating on the TM₀₁₀ mode at 36 GHz, the third harmonic of the 12 GHz linac frequency, with an efficiency of 44% and 10.6 MW radiofrequency output power. We discuss also here the high-power DC gun with the related magnetic focusing system, the RF beam dynamics and finally the multiphysics analysis of a high- power microwave window for a Ka-band klystron providing 16MW of peak power.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS022
About •	Received ※ 18 May 2022 — Revised ※ 12 June 2022 — Accepted ※ 18 June 2022 — Issue date ※ 10 July 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOMS052	6 MeV Novel Hybrid (Standing Wave - Traveling Wave) Photo-Cathode Electron Gun for a THz Superradiant FEL	gun, electron, cathode, experiment	760
	A. Nause, L. Feigin, A. Friedman, A. Weinberg Ariel University, Ariel, Israel A. Fukasawa, J.B. Rosenzweig UCLA, Los Angeles, California, USA B. Spataro LNF-INFN, Frascati, Italy
	A novel 6 MeV hybrid photo injector was designed and commissioned at Ariel University in Israel as an on-going collaboration with UCLA. This unique, new generation design provides a radically simpler approach to RF feeding of a gun/buncher system, leading to a much shorter beam via velocity bunching owed to an attached traveling wave section of the photo-injector. This design results in better performance in beam parameters, providing a high quality electron beam, with energy of 6 MeV, emittance of less than 3 ’m, and a 150 fs pulse duration at up to 1 nC per pulse. The Hybrid gun is driven by a SLAC XK5 Klystron as the high power RF source, and third harmonic of a fs level IR Laser amplifier (266 nm) to extract electrons from the Cathode. The unique e-gun will produce a bunched electron pulse to drive a THz FEL, which will operate at the super-radiance regime, and therefore requires extraordinary beam properties. It will also be used for MeV UED experiments in a separate line using a dogleg section. Here we describe the gun and presents experimental results from the gun and its sub-systems, including energy and charge measurements, compared with the design simulations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS052
About •	Received ※ 11 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 18 June 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOST002	Upgrade of the 25 MW RF Station for the Linear Accelerator LINAC2 at ELSA	electron, linac, monitoring, GUI	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)

TUPOST015	Commissioning and First Results of an X-Band LLRF System for TEX Test Facility at LNF-INFN	LLRF, MMI, GUI, network	876
	L. Piersanti, D. Alesini, M. Bellaveglia, S. Bini, B. Buonomo, F. Cardelli, C. Di Giulio, E. Di Pasquale, M. Diomede, L. Faillace, A. Falone, G. Franzini, A. Gallo, G. Giannetti, A. Liedl, D. Moriggi, S. Pioli, S. Quaglia, L. Sabbatini, M. Scampati, G. Scarselletta, A. Stella, S. Tocci, L. Zelinotti LNF-INFN, Frascati, Italy
	Funding: Latino is a project co-funded by Regione Lazio within POR-FESR 2014-2020 program In the framework of LATINO project (Laboratory in Advanced Technologies for INnOvation) funded by Lazio regional government, the commissioning of the TEst stand for X-band (TEX) facility has started in 2021 at Frascati National Laboratories of INFN. Born as a collaboration with CERN to test high gradient accelerating structures, during 2022 TEX aims at feeding the first EuPRAXIA@SPARC_LAB X-band structure prototype. During 2021 the commissioning has been successfully carried out up to 48 MW. The power unit is driven by an X-band low level RF system, that employs a commercial S-band (2.856 GHz) Libera digital LLRF (manufactured by Instrumentation Technologies), with an up/down conversion stage and a reference generation and distribution system able to produce coherent frequencies for the American S-band and European X-band (11.994 GHz), both designed and realized at LNF. The performance of the system, with a particular focus on amplitude and phase resolution, together with klystron and driver amplifier jitter measurements, will be reviewed in this paper. Moreover, considerations on its suitability and main limitations in view of EuPRAXIA@SPARC_LAB project will be discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST015
About •	Received ※ 20 May 2022 — Revised ※ 13 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 28 June 2022
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TUPOPT035	Introduction of Westwood Linear Accelerator Test Facility in University of California Los Angeles	gun, laser, electron, FEL	1085
	Y. Sakai, G. Andonian, O. Camacho, A. Fukasawa, G.E. Lawler, N. Majernik, P. Manwani, B. Naranjo, J.B. Rosenzweig, O. Williams UCLA, Los Angeles, California, USA
	Funding: U.S. DOE: DE-SC0009914 U.S. DOD: DARPA GRIT Contract 20204571 U.S. DOE: DE-SC0020409 - Cryo RF An electron linear accelerator test facility located on UCLA’s southwest campus in Westwood, SAMURAI, is presently being constructed. A RF-based accelerator consists of a compact, 3 MeV S-band hybrid gun capable of velocity bunching to bunch lengths in the 100s fs range with 100s pC of charge. This beam is accelerated by an 1.5 m S-band linac with a peak output energy of 30 MeV which can be directed to either a secondary beamline or remain on the main beamline for final acceleration by a SLAC 3 m S-band linac to an energy of 80 MeV. Further acceleration by advanced boosters such as a cryo-cooled C-band structure or numerous optical or wakefield methods is under active investigation. In combination with a 3 TW Ti:Sapphire laser, initial proof of principle experiments will be conducted on topics including the ultra-compact x-ray free-electron laser, advanced dielectric wakefield acceleration, bi-harmonic nonlinear inverse Compton scattering, and various radiation detectors. Furthermore, development of a tertiary beamline based on an ultra low emittance, cryo-cooled gun will eventually enable two-beam experiments, expanding the facility’s unique experimental capabilities.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOPT035
About •	Received ※ 08 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 20 June 2022 — Issue date ※ 24 June 2022
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TUPOPT061	Status and Commissioning of the First X-Band RF Source of the TEX Facility	GUI, MMI, LLRF, controls	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
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TUPOTK028	Tuning of Superconducting Cavities Using the FFT of Transmitted Power	cavity, resonance, operation, SRF	1268
	E. Laface, C.G. Maiano, P. Pierini, M.Y. Wang ESS, Lund, Sweden
	We implemented a method to tune the ESS superconducting cavities based on the spectral analysis of the high resolution data available from the Low Level RF system (LLRF) for the transmitted power, without the need of connecting a network analyzer or any other dedicated instrumentation along the RF chain. A frequency peak up to 4 MHz off from the resonating frequency can be detected and used to control the stepper motor of the tuner until the cavity is stretched to the proper length to reach the correct operation frequency. Experience of its use at the ESS Test Stand 2 (TS2) facility at Lund during cryomodule acceptance testing is presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK028
About •	Received ※ 16 May 2022 — Revised ※ 11 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 14 June 2022
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TUPOTK053	Design Progress of High Efficiency Klystron for CEPC LINAC	simulation, cavity, gun, linac	1339
	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
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TUPOMS058	C-Band High Gradient Testing of the Benchmark a/λ=0.105 Cavity	cavity, GUI, coupling, electron	1564
	E.I. Simakov, V. Gorelov, T. Tajima, M.R.A. Zuboraj LANL, Los Alamos, New Mexico, USA S. Biedron Element Aero, Chicago, USA S. Biedron UNM-ECE, Albuquerque, USA M.E. Middendorf ORNL RAD, Oak Ridge, Tennessee, USA
	Funding: Los Alamos National Laboratory LDRD Program This poster will report the results of high gradient testing of the benchmark C-band RF cavity. Modern applications such as X-ray sources require accelerators with optimized cost of construction and operation, naturally calling for high-gradient acceleration. At LANL we commissioned a test stand (CERF-NM) powered by a 50 MW, 5.712 GHz Canon klystron. The test stand is capable of conditioning accelerating cavities for operation at surface electric fields in excess of 300 MV/m. CERF-NM is the first high gradient C-band test facility in the United States. An important milestone for this test stand is to demonstrate conditioning and high gradient testing of the most basic high gradient RF cavity with a geometry that has been extensively studied at other frequencies, such as X-band. The cavity is the three-cell structure with the highest gradient in the central cell and two coupling cells, and the ratio of the radius of the coupling iris to the wavelength a/\lamda=0.105. This presentation will report achieved gradients, breakdown probabilities, and other characteristics measured during the high power operation of this cavity.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS058
About •	Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 17 June 2022
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TUPOMS060	High Gradient Conditioning and Performance of C-Band ß=0.5 Proton Normal- Conducting Copper and Copper-Silver Radio-Frequency Accelerating Cavities	cavity, proton, operation, coupling	1567
	M.R.A. Zuboraj, R.L. Fleming, V. Gorelov, J.W. Lewellen, M.E. Middendorf, E.I. Simakov LANL, Los Alamos, New Mexico, USA S.V. Baryshev, M.E. Schneider Michigan State University, East Lansing, Michigan, USA V.A. Dolgashev, E.A. Nanni, E.J.C. Snively, S.G. Tantawi SLAC, Menlo Park, California, USA E. Jevarjian MSU, East Lansing, Michigan, USA
	Funding: LANL-LDRD This work presents the results of high gradient testing of the two C-band (5.712 GHz) normal conducting ß=0.5 accelerating cavities. The first cavity was made of copper and second was made of copper-silver alloy with 0.08% silver concentration. The tests were conducted at the C-Band Engineering Research Facility of New Mexico (CERF-NM) located at Los Alamos National Laboratory Both cavities achieved gradients in excess of 200 MV/m and surface electric fields in excess of 300 MV/m. The breakdown rates were mapped as functions of the gradient and peak surface fields. The gradients and peak surface fields observed in the copper-silver cavity were about 20% higher than those in the pure copper cavity with the same breakdown rate. It was concluded that the dominant breakdown mechanism in these cavities was not the pulse heating but the breakdown due to very high surface electric fields.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS060
About •	Received ※ 08 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 19 June 2022
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WEPOPT024	Beam Loading Compensation of Standing Wave Linac with Off-Crest Acceleration	positron, cavity, beam-loading, acceleration	1893
	M. Kuriki, S. Konno, Z.J. Liptak HU/AdSM, Higashi-Hiroshima, Japan M.K. Fukuda, T. Omori, Y. Seimiya, J. Urakawa, K. Yokoya KEK, Ibaraki, Japan S. Kashiwagi Tohoku University, Research Center for Electron Photon Science, Sendai, Japan H. Tajino HU ADSE, Hiroshima, Japan T. Takahashi Hiroshima University, Graduate School of Science, Higashi-Hiroshima, Japan
	In E-Driven positron source of ILC, the generated positron is captured by a standing wave cavity. Because the deceleration capture method is employed, the positron is off-crest over the linac. Because the beam-loading is expected to be more than 1A in a multi-bunch format, the compensation is essential to obtain uniform intensity over the pulse. A conventional method for the compensation controlling the timing doesn’t work because RF and Beam induced field are in different phase. In this manuscript, we discuss the compensation with the off-crest acceleration case. A simple phase modulation on the input RF is a solution.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT024
About •	Received ※ 20 May 2022 — Revised ※ 10 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 16 June 2022
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THOXSP3	Path to High Repetition Rate Seeding: Combining High Gain Harmonic Generation with an Optical Klystron	FEL, electron, laser, simulation	2411
	G. Paraskaki, E. Ferrari, L. Schaper, E. Schneidmiller DESY, Hamburg, Germany E. Allaria Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy W. Hillert University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
	External seeding in combination with harmonic generation has become a hot topic in the field of high gain free-electron lasers (FELs) since it allows delivery of superior FEL radiation characterized by, for example, full coherence and unprecedented shot-to-shot stability. At low repetition rate machines operating at few 10 Hz, novel experiments have been realized already, however, at superconducting machines, current laser technology does not support exploiting the full repetition rate available. One way to overcome this problem is to reduce the requirements in seed laser power: here, an optical klystron based high gain harmonic generation (HGHG) setup is proposed to reduce the laser peak power requirements by orders of magnitude, enabling operation at drastically increased repetition rates. We report simulation results based on the seeded beamline concept of the FLASH2020+ project. Among other topics, the effect of a linear electron beam energy chirp on this setup will be discussed.
	Slides THOXSP3 [1.502 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THOXSP3
About •	Received ※ 08 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 27 June 2022
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FROXSP3	First Operation of a Klystron Fitted with a Superconducting MgB₂ Solenoid	solenoid, operation, vacuum, superconductivity	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

Other Keywords

Page

MOPOMS022

Studies of a Ka-Band High Power Klystron Amplifier at INFN-LNF

cavity, electron, gun, focusing

683

M. Behtouei, L. Faillace, A. Mostacci, B. Spataro
LNF-INFN, Frascati, Italy
F. Bosco, M. Carillo, M. Migliorati, A. Mostacci, L. Palumbo
Sapienza University of Rome, Rome, Italy
F. Di Paolo, S. Fantauzzi, A. Leggieri, F. Marrese, L. Valletti
Università degli Studi di Roma "Tor Vergata", Roma, Italy
G. Torrisi
INFN/LNS, Catania, Italy

In the framework of the Compact Light XLS project, a Ka-band linearizer with electric field ranging from 100 to 150 MV/m is requested. In order to feed this structure, a proper Ka-band high power klystron amplifier with a high efficiency is needed. This paper reports a possible solution for a klystron amplifier operating on the TM₀₁₀ mode at 36 GHz, the third harmonic of the 12 GHz linac frequency, with an efficiency of 44% and 10.6 MW radiofrequency output power. We discuss also here the high-power DC gun with the related magnetic focusing system, the RF beam dynamics and finally the multiphysics analysis of a high- power microwave window for a Ka-band klystron providing 16MW of peak power.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS022

About •

Received ※ 18 May 2022 — Revised ※ 12 June 2022 — Accepted ※ 18 June 2022 — Issue date ※ 10 July 2022

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

MOPOMS052

6 MeV Novel Hybrid (Standing Wave - Traveling Wave) Photo-Cathode Electron Gun for a THz Superradiant FEL

gun, electron, cathode, experiment

760

A. Nause, L. Feigin, A. Friedman, A. Weinberg
Ariel University, Ariel, Israel
A. Fukasawa, J.B. Rosenzweig
UCLA, Los Angeles, California, USA
B. Spataro
LNF-INFN, Frascati, Italy

A novel 6 MeV hybrid photo injector was designed and commissioned at Ariel University in Israel as an on-going collaboration with UCLA. This unique, new generation design provides a radically simpler approach to RF feeding of a gun/buncher system, leading to a much shorter beam via velocity bunching owed to an attached traveling wave section of the photo-injector. This design results in better performance in beam parameters, providing a high quality electron beam, with energy of 6 MeV, emittance of less than 3 ’m, and a 150 fs pulse duration at up to 1 nC per pulse. The Hybrid gun is driven by a SLAC XK5 Klystron as the high power RF source, and third harmonic of a fs level IR Laser amplifier (266 nm) to extract electrons from the Cathode. The unique e-gun will produce a bunched electron pulse to drive a THz FEL, which will operate at the super-radiance regime, and therefore requires extraordinary beam properties. It will also be used for MeV UED experiments in a separate line using a dogleg section. Here we describe the gun and presents experimental results from the gun and its sub-systems, including energy and charge measurements, compared with the design simulations.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS052

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Received ※ 11 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 18 June 2022

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

TUPOST002

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

electron, linac, monitoring, GUI

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

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

TUPOST015

Commissioning and First Results of an X-Band LLRF System for TEX Test Facility at LNF-INFN

LLRF, MMI, GUI, network

876

L. Piersanti, D. Alesini, M. Bellaveglia, S. Bini, B. Buonomo, F. Cardelli, C. Di Giulio, E. Di Pasquale, M. Diomede, L. Faillace, A. Falone, G. Franzini, A. Gallo, G. Giannetti, A. Liedl, D. Moriggi, S. Pioli, S. Quaglia, L. Sabbatini, M. Scampati, G. Scarselletta, A. Stella, S. Tocci, L. Zelinotti
LNF-INFN, Frascati, Italy

Funding: Latino is a project co-funded by Regione Lazio within POR-FESR 2014-2020 program
In the framework of LATINO project (Laboratory in Advanced Technologies for INnOvation) funded by Lazio regional government, the commissioning of the TEst stand for X-band (TEX) facility has started in 2021 at Frascati National Laboratories of INFN. Born as a collaboration with CERN to test high gradient accelerating structures, during 2022 TEX aims at feeding the first EuPRAXIA@SPARC_LAB X-band structure prototype. During 2021 the commissioning has been successfully carried out up to 48 MW. The power unit is driven by an X-band low level RF system, that employs a commercial S-band (2.856 GHz) Libera digital LLRF (manufactured by Instrumentation Technologies), with an up/down conversion stage and a reference generation and distribution system able to produce coherent frequencies for the American S-band and European X-band (11.994 GHz), both designed and realized at LNF. The performance of the system, with a particular focus on amplitude and phase resolution, together with klystron and driver amplifier jitter measurements, will be reviewed in this paper. Moreover, considerations on its suitability and main limitations in view of EuPRAXIA@SPARC_LAB project will be discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST015

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Received ※ 20 May 2022 — Revised ※ 13 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 28 June 2022

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

TUPOPT035

Introduction of Westwood Linear Accelerator Test Facility in University of California Los Angeles

gun, laser, electron, FEL

1085

Y. Sakai, G. Andonian, O. Camacho, A. Fukasawa, G.E. Lawler, N. Majernik, P. Manwani, B. Naranjo, J.B. Rosenzweig, O. Williams
UCLA, Los Angeles, California, USA

Funding: U.S. DOE: DE-SC0009914 U.S. DOD: DARPA GRIT Contract 20204571 U.S. DOE: DE-SC0020409 - Cryo RF
An electron linear accelerator test facility located on UCLA’s southwest campus in Westwood, SAMURAI, is presently being constructed. A RF-based accelerator consists of a compact, 3 MeV S-band hybrid gun capable of velocity bunching to bunch lengths in the 100s fs range with 100s pC of charge. This beam is accelerated by an 1.5 m S-band linac with a peak output energy of 30 MeV which can be directed to either a secondary beamline or remain on the main beamline for final acceleration by a SLAC 3 m S-band linac to an energy of 80 MeV. Further acceleration by advanced boosters such as a cryo-cooled C-band structure or numerous optical or wakefield methods is under active investigation. In combination with a 3 TW Ti:Sapphire laser, initial proof of principle experiments will be conducted on topics including the ultra-compact x-ray free-electron laser, advanced dielectric wakefield acceleration, bi-harmonic nonlinear inverse Compton scattering, and various radiation detectors. Furthermore, development of a tertiary beamline based on an ultra low emittance, cryo-cooled gun will eventually enable two-beam experiments, expanding the facility’s unique experimental capabilities.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOPT035

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Received ※ 08 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 20 June 2022 — Issue date ※ 24 June 2022

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TUPOPT061

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

GUI, MMI, LLRF, controls

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.

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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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TUPOTK028

Tuning of Superconducting Cavities Using the FFT of Transmitted Power

cavity, resonance, operation, SRF

1268

E. Laface, C.G. Maiano, P. Pierini, M.Y. Wang
ESS, Lund, Sweden

We implemented a method to tune the ESS superconducting cavities based on the spectral analysis of the high resolution data available from the Low Level RF system (LLRF) for the transmitted power, without the need of connecting a network analyzer or any other dedicated instrumentation along the RF chain. A frequency peak up to 4 MHz off from the resonating frequency can be detected and used to control the stepper motor of the tuner until the cavity is stretched to the proper length to reach the correct operation frequency. Experience of its use at the ESS Test Stand 2 (TS2) facility at Lund during cryomodule acceptance testing is presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK028

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Received ※ 16 May 2022 — Revised ※ 11 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 14 June 2022

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TUPOTK053

Design Progress of High Efficiency Klystron for CEPC LINAC

simulation, cavity, gun, linac

1339

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.

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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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TUPOMS058

C-Band High Gradient Testing of the Benchmark a/λ=0.105 Cavity

cavity, GUI, coupling, electron

1564

E.I. Simakov, V. Gorelov, T. Tajima, M.R.A. Zuboraj
LANL, Los Alamos, New Mexico, USA
S. Biedron
Element Aero, Chicago, USA
S. Biedron
UNM-ECE, Albuquerque, USA
M.E. Middendorf
ORNL RAD, Oak Ridge, Tennessee, USA

Funding: Los Alamos National Laboratory LDRD Program
This poster will report the results of high gradient testing of the benchmark C-band RF cavity. Modern applications such as X-ray sources require accelerators with optimized cost of construction and operation, naturally calling for high-gradient acceleration. At LANL we commissioned a test stand (CERF-NM) powered by a 50 MW, 5.712 GHz Canon klystron. The test stand is capable of conditioning accelerating cavities for operation at surface electric fields in excess of 300 MV/m. CERF-NM is the first high gradient C-band test facility in the United States. An important milestone for this test stand is to demonstrate conditioning and high gradient testing of the most basic high gradient RF cavity with a geometry that has been extensively studied at other frequencies, such as X-band. The cavity is the three-cell structure with the highest gradient in the central cell and two coupling cells, and the ratio of the radius of the coupling iris to the wavelength a/\lamda=0.105. This presentation will report achieved gradients, breakdown probabilities, and other characteristics measured during the high power operation of this cavity.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS058

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Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 17 June 2022

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TUPOMS060

High Gradient Conditioning and Performance of C-Band ß=0.5 Proton Normal- Conducting Copper and Copper-Silver Radio-Frequency Accelerating Cavities

cavity, proton, operation, coupling

1567

M.R.A. Zuboraj, R.L. Fleming, V. Gorelov, J.W. Lewellen, M.E. Middendorf, E.I. Simakov
LANL, Los Alamos, New Mexico, USA
S.V. Baryshev, M.E. Schneider
Michigan State University, East Lansing, Michigan, USA
V.A. Dolgashev, E.A. Nanni, E.J.C. Snively, S.G. Tantawi
SLAC, Menlo Park, California, USA
E. Jevarjian
MSU, East Lansing, Michigan, USA

Funding: LANL-LDRD
This work presents the results of high gradient testing of the two C-band (5.712 GHz) normal conducting ß=0.5 accelerating cavities. The first cavity was made of copper and second was made of copper-silver alloy with 0.08% silver concentration. The tests were conducted at the C-Band Engineering Research Facility of New Mexico (CERF-NM) located at Los Alamos National Laboratory Both cavities achieved gradients in excess of 200 MV/m and surface electric fields in excess of 300 MV/m. The breakdown rates were mapped as functions of the gradient and peak surface fields. The gradients and peak surface fields observed in the copper-silver cavity were about 20% higher than those in the pure copper cavity with the same breakdown rate. It was concluded that the dominant breakdown mechanism in these cavities was not the pulse heating but the breakdown due to very high surface electric fields.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS060

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Received ※ 08 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 19 June 2022

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WEPOPT024

Beam Loading Compensation of Standing Wave Linac with Off-Crest Acceleration

positron, cavity, beam-loading, acceleration

1893

M. Kuriki, S. Konno, Z.J. Liptak
HU/AdSM, Higashi-Hiroshima, Japan
M.K. Fukuda, T. Omori, Y. Seimiya, J. Urakawa, K. Yokoya
KEK, Ibaraki, Japan
S. Kashiwagi
Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
H. Tajino
HU ADSE, Hiroshima, Japan
T. Takahashi
Hiroshima University, Graduate School of Science, Higashi-Hiroshima, Japan

In E-Driven positron source of ILC, the generated positron is captured by a standing wave cavity. Because the deceleration capture method is employed, the positron is off-crest over the linac. Because the beam-loading is expected to be more than 1A in a multi-bunch format, the compensation is essential to obtain uniform intensity over the pulse. A conventional method for the compensation controlling the timing doesn’t work because RF and Beam induced field are in different phase. In this manuscript, we discuss the compensation with the off-crest acceleration case. A simple phase modulation on the input RF is a solution.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT024

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Received ※ 20 May 2022 — Revised ※ 10 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 16 June 2022

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THOXSP3

Path to High Repetition Rate Seeding: Combining High Gain Harmonic Generation with an Optical Klystron

FEL, electron, laser, simulation

2411

G. Paraskaki, E. Ferrari, L. Schaper, E. Schneidmiller
DESY, Hamburg, Germany
E. Allaria
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
W. Hillert
University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany

External seeding in combination with harmonic generation has become a hot topic in the field of high gain free-electron lasers (FELs) since it allows delivery of superior FEL radiation characterized by, for example, full coherence and unprecedented shot-to-shot stability. At low repetition rate machines operating at few 10 Hz, novel experiments have been realized already, however, at superconducting machines, current laser technology does not support exploiting the full repetition rate available. One way to overcome this problem is to reduce the requirements in seed laser power: here, an optical klystron based high gain harmonic generation (HGHG) setup is proposed to reduce the laser peak power requirements by orders of magnitude, enabling operation at drastically increased repetition rates. We report simulation results based on the seeded beamline concept of the FLASH2020+ project. Among other topics, the effect of a linear electron beam energy chirp on this setup will be discussed.

Slides THOXSP3 [1.502 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THOXSP3

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Received ※ 08 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 27 June 2022

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FROXSP3

First Operation of a Klystron Fitted with a Superconducting MgB₂ Solenoid

solenoid, operation, vacuum, superconductivity

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]

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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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