RuPAC2016 - Classification: RF power structures and systems

Paper	Title	Page
THCDMH02	Recent Optimized Design of ILC Cryomodule With Explosion Welding Technology	141
	B.M. Sabirov JINR, Dubna, Moscow Region, Russia
	Primary purpose of this experiment is the development of techniques to simplify and make cheaper the construction of the cryomodules. In the current ILC TDR design the helium vessel and the connected pipes are made of expensive titanium. JINR in association with INFN several designs for these transitions have been produced and studied during the last years. The results of measuring microhardness by Vickers microindentation are issued of ~3.8 GPa and the breaking strength was 375 MPa. Helium leak measurements revealed no leaks at a background leak rate of 0.410^-10 atmcc/s. For imitation of use transition sample in real working position, connected with Nb cavity, Nb rings were joint with Nb pipe of samples by EBW. Superposition of all residual stresses may result plastic deformation, failure of welds, and consequently occurrence of a leak. Test result of thermocycles in LHe and in the LN ussued absence of leak at background leak rate ~0.510^-10 atmcc/sec. The results showed the full eligibility of suggested design Nb+Ti+SS transition sample not for only Linear Collider, but for any cryogenic systems.
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TUCBSH01	Next Generation High Power Solid-State RF Sources
	G.B. Sharkov, T.V. Bondarenko, A.A. Krasnov, S.A. Polikhov NIITFA, Moscow, Russia
	Solid-state RF power amplifier (SSPA) technology has developed significantly over recent years. Powers of hundreds of kilowatts are being achieved, driven by the developments of LDMOS and other transistor technologies. The price and size of SSPA still correlate with the output power, which is not the case for vacuum tube based devices. In order to be competitive with vacuum tubes at higher levels of power and frequency, SSPA's should be designed to be more compact and cheaper than current offerings, using the high efficiency and reliability of modern transistors to produce highly available amplifier systems. The scalability of SSPA output power is achieved by a modular architecture based on several ~1kW transistors; this gives an important advantage over vacuum tubes. In order to meet challenging demands for high power, efficient, reliable, compact and cost effective RF amplifiers, the next generation architecture of SSPA is employed and single design for various frequencies and power is proposed.
	Slides TUCBSH01 [7.332 MB]
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THXSH01	Development of the INR Linear Accelerator DTL RF System	191
	A.I. Kvasha, V.L. Serov RAS/INR, Moscow, Russia A. Feschenko MIPT, Dolgoprudniy, Moscow Region, Russia
	The regular INR DTL RF system operation began in 1992. By this point three new type of vacuum tube, designed purposely for INR linear accelerator, were manufactured at OKB "Swetlana" in the amount sufficient for RF system operation during 20 years. Among them were two vacuum tubes for final RF power amplifier - GI-54A and RF driver - GI-51A and also vacuum tube for powerful anode modulator - GMI-44A. In the late 80s manufacture of these vacuum tubes was stopped and since 1990 designing of new vacuum tube for RF output power amplifier instead of GI-54A was started. The new vacuum tube GI-71A with output RF power up to 3 MW in pulse, plate power dissipation up to 120 kW and power gain about 10 was simpler and less expensive in comparison with GI-54A. The transition to new vacuum tube began in 1999 and finished in 2014. Successful testing of GI-57A as RF driver, fulfilled in 2008, opened the possibility of replacement GI-51A. As for GMI-44A replacement there are no analogues, produced in Russian federation, and, as it turned out, the only option was GI-71A again. Below some problems, connected with the vacuum tubes replacement, as well as main results of twenty years DTL RF system operation are considered.
	Slides THXSH01 [4.748 MB]
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THXSH02	Three Transverse Deflecting Systems for Electron Beam Diagnostics in the European Free-Electron Laser XFEL	196
	A.A. Zavadtsev RAS/INR, Moscow, Russia
	Funding: European XFEL GmbH, Ministry of Education and Science of Russia In frames of Russian in-kind contribution to Europe-an XFEL, INR in cooperation with DESY is responsible for Transverse Deflecting Systems (TDS) for special beam diagnostic in the XFEL linac. Three TDS have been developed: TDS INJ in the Injector, TDS BC1 in the Accelerator tunnel after Bunch Compressor 1 and TDS BC1 after Bunch Compressor 2. Each system in-cludes S-band disk-loaded deflecting structure (DLS), waveguide system, klystron, pulse transformer, modu-lator and control system. TDS INJ has been built, as-sembled in the Injector building and tested. It is used to monitor the bunch length, longitudinal phase space and slice emittance now. Exceptionally small, exceed-ing expectations, slice emittance of electron bunch was measured using TDS INJ during the XFEL Injector commissioning. Three structures for TDS BC1 and TDS BC2 as well as the waveguide systems have been built, tested and TDS BC2 part installed in the XFEL tunnel. On behalf of the joint XFEL TDS team
	Slides THXSH02 [16.400 MB]
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THCASH01	Effective RF Deflecting Structures for Bunch Rotation and Deflection	201
	V.V. Paramonov RAS/INR, Moscow, Russia
	Deflecting RF Structures find now applications for the bunch rotation with the purposes of diagnostic for the longitudinal distribution, emittance exchange and for the luminosity improvements in colliders. Report describes results of R&D program for development of deflectors with minimized level of aberrations in the distribution of deflecting field. Such structures, applied for bunch rotation along transverse axis, provide much smaller emittence growth, as compared to another options. In comparison with classical and widely used deflectors, based on disk loaded waveguide, developed structures have, depending on modification, in 2-6 times higher RF efficiency. Structures can operate both in Traveling Wave (TW) and in Standing Wave (SW) modes. To create long RF cavities for SW operation, compensated (bi-periodical) options are developed, combining field stability and high RF efficiency. The problem of stabilization for the plane of deflection is removed due to essentially 3D geometry. The main solutions for such structures development are described and achieved parameters are reported.
	Slides THCASH01 [6.084 MB]
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TUPSA027	The Study of the Helical RF Resonator for the 300 keV Nitrogen Ion CW Implanter	270
	N.V. Avreline TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada P.G. Alexey, S.M. Polozov MEPhI, Moscow, Russia
	The helical RF resonator for the single charged 300 keV nitrogen ion CW implanter was designed, simulated in CST Microwave Studio and the results were experimentally verified. The current setup of the implanter is described as well as possible modifications to accelerate ions of other types. The results of the field distribution's RF measurements and the results of the high-power test are also presented.
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TUPSA029	High Power Solid State RF Generator for Neutral Beam Injector	276
	E. Shubin, V.V. Kolmogorov BINP SB RAS, Novosibirsk, Russia A.S. Styuf NSU, Novosibirsk, Russia
	Neutral Beam Heating Injector of 1 MW beam power for the TCV tokamak (Lausanne, Switzerland) was developed in BINP. The plasma is formed in a plasma box with inductively coupled RF power at frequency about 4 MHz. Required RF power in the plasma box is up to 40 kW during the period of 2 seconds with 5 minutes intervals. Solid state RF generator with such capability has been developed in BINP. The generator has a modular structure with combining RF power of 16 identical modules. Output RF power of the generator is regulated by DC power supply voltage. At present Injector is working at TCV. Description of the RF generator design, main features and the test results are presented in the report.
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TUPSA030	Regulation of the Waveguide Coupling Factor of Standing Wave Linear Accelerator	279
	D.S. Yurov MSU, Moscow, Russia V.I. Shvedunov LEA MSU, Moscow, Russia V.I. Shvedunov SINP MSU, Moscow, Russia
	Regulation of the waveguide coupling factor of standing wave linear accelerator allows to adjust the value of accelerated current, keeping the reflected RF power close to zero. This ensures the most efficient use of RF energy and absence of overvoltage in the waveguide elements. The paper presents studies results for various methods of coupling factors regulation with continuous wave (CW) normal conducting linear accelerator used as an example. The results of calculations and measurements on the mock-up of the accelerating structure are presented.
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TUPSA031	The Cascade Interference Switch Comprising a Transmission Resonator	282
	S.A. Gorev, S.N. Artemenko, V.S. Igumnov TPU, Tomsk, Russia
	The new concept of microwave interference switches is reported. Interference switch is based on series of H-plane T-junctions (cascade switch) in the view of decreasing switched power at Off state and comprises irises in both its own input and output arms. At On state the irises act as a transmission resonator localizing the nodes of the standing wave at the junctions. Such distribution is expected to decrease the plasma losses. It was shown with a simulation that the cascade switch with additional irises increases the efficiency of the active microwave compressors. The simulation was made with CST studio and COMSOL.
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TUPSA032	Input Coupler Design for IH-Based Accelerating Structure
	S.E. Toporkov, A.S. Bogomolov, M.V. Lalayan, G.S. Pomogaybo MEPhI, Moscow, Russia
	Design of the input/output couplers for Interdigital H-mode (IH) proton accelerating structures operating in travelling wave regime has a range of tasks to be solved. Most of the difficulties are caused by low working frequency band which is far below the cutoff frequency of the cylindrical waveguide. To get an appropriate coupling with the slow-wave structure a coaxial coupler design is considered. Reduction of reflected harmonic and coupler matching is performed by end-cell geometry modification. Two types of accelerating structure: classical IH-structure and modified compact version are considered. Both have 433MHz operating frequency. Results of the main electrodynamic characteristics, end-cell optimization and thermal heating for different power levels are presented.
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TUPSA034	520 MeV TRIUMF Cyclotron RF System: Maintenance, Tuning and Protection	285
	N.V. Avreline, T. Au, I.V. Bylinskii, B. Jakovljevic, V. Zvyagintsev TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada C.D. Bartlett University of Victoria, Victoria BC, Canada
	Funding: TRIUMF receives federal funding via a contribution agreement through the National Research Council of Canada. 1 MW CW 23 MHz RF system of the TRIUMF's 520 MeV Cyclotron has been in operation for over 40 years. Continuous development of the RF power amplifiers, the waveguide system and the measurement and protection devices provides reliable operation and improves the performance of the RF System. In this article, operation and maintenance procedures of this RF system are analysed and recent as well as future upgrades are being analysed and discussed. In particular, we discuss the improvements of the transmission line's VSWR monitor and its effect on the protection of the RF system against RF breakdowns and sparks. We discuss the new version of the input circuit that was installed, tested and is currently used in the final stage of RF power amplifier. We analyse various schematics and configurations of the Intermediate Power Amplifier (IPA) to be deployed in the future.
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TUPSA035	Estimation of Multipacting in CDS Structure	288
	I.V. Rybakov RAS/INR, Moscow, Russia I.I. Isaev DESY Zeuthen, Zeuthen, Germany
	The Cut Disk Structure (CDS) is recommended for replacement of the first cavity of the main part of INR linac. For the cavity work stability there should be no multipactor at operating regime. CDS structure was first set on exploitation at DESY PITZ electron linac. For this cavity according to the analytical estimation multipaction should appear at the operating power level in coupling cells, but it was not approved by the numerical simulation with both accelerating and coupling modes excitation for RF energy transfer along the cavity. The multipactor appears only with the secondaty emission yield (SEY) growth which could happen if the inner surface of the cavity is polluted. The results of multipactor investigation in CDS PITZ were used as reference for the CDS structure for the first cavity of the main part of INR linac. The analytical estimation and numerical simulation of multipactor in CDS INR structure shows the appearance of the discharge in coupling cells with the OFC copper SEY for the operating regime of the cavity. An option for the multipactor damping with the forced excitation of oscillations in coupling cell with voltage higher than upper multipactor limit was considered.
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TUPSA036	Manufacturing Tolerances Estimation for Proton Linac Cavities	291
	I.V. Rybakov, V.V. Paramonov, A.K. Skasyrskaya RAS/INR, Moscow, Russia
	The definition of manufacturing tolerances is one of the stages of accelerating structure construction. In case of proton linacs the value of accelerating field homogeneity is a critical parameter. It depends both on cells frequencies perturbations and the coupling coefficient perturbations. These values could be obtained using the numerical simulations of the characteristic electromagnetic oscillations in the cell. There is the method that allows the reduction of the simulations time and to avoid separate simulations for each geometrical parameter of the structure. This method was improved and extended for the pi/2-wave, pi-wave and travelling wave structures. Several examples of the method application, including the structure for the first cavity of the main part of INR linac, are presented.
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TUPSA037	Powerfull RF Triode as Anode Modulator Vacuum Tube	294
	A.I. Kvasha, V.L. Serov RAS/INR, Moscow, Russia
	For 20 years modulator vacuum tube GMI-44A successfully operated in DTL RF system of INR Linac. The vacuum tube had been designed and manufactured at OKB "Swetlana" in the 70s-80s of the last century. The quantity of manufactured tubes - about 80, had allowed the accelerator operating till now. Manufacture of the tubes was stopped In the mid 80s. Attempts of the GMI-44A manufacture restoration or repair were unsuccessful ones. As it turned out, the only decision in the circumstances was using of 200 MHz powerful pulse triode GI-71A as modulator tube. The vacuum tubes GI-71A were installed for the last ten years in all output RF power amplifiers (PA) of INR Linac instead of RF pulse triode GI-54A. In the paper some problems appearing after modulator vacuum tube replacement are discussed.
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TUPSA038	The RF Power System for RFQ-Injector of Linac-20	297
	V.G. Kuzmichev, A.V. Kozlov, T. Kulevoy, S.M. Polozov, D.N. Selesnev, Yu. Stasevich ITEP, Moscow, Russia A.V. Butenko JINR, Dubna, Moscow Region, Russia T. Kulevoy, S.M. Polozov MEPhI, Moscow, Russia
	In the frame of the Nuclotron-M project the electrostatic injector of LU-20 is replaced by a RFQ accelerator, which has been developed in ITEP. The construction of 400 kW, 145 MHz RF system for RFQ-injector are described. Pa-rameters and test results of the RF power system operated on the resistive load and on RFQ during ion beam accele-ration are presented
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TUPSA046	Experimental Analysis of Dipole Modes in Elliptical Cavity	313
	Ya.V. Shashkov, M.V. Lalayan, N.P. Sobenin MEPhI, Moscow, Russia A. Orlov NRNU, Moscow, Russia
	The experimental measurements of transverse shunt impedance for higher order modes TM110 and TE111 for S-band elliptical cavity were carried out. The experiments using dielectric and metallic spheres as perturbing objects and with ring probe were done.
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TUPSA068	Simulation of S-Band RF Gun with RF Beam Control	345
	A.M. Barnyakov, A.E. Levichev, D.A. Nikiforov BINP SB RAS, Novosibirsk, Russia M.V. Maltseva NSU, Novosibirsk, Russia
	The design and operation of electron RF gun with RF beam control are described. Results of numerical simulation of electromagnetic fields and beam dynamics are presented. RF gun consists of two resonators operating at E010 mode with 180 degrees phase shift at frequency of 2856 MHz. RF control is carried out via coaxial resonator with grid-cathode capacity. Accordint to result of the simulation, RF gun with RF control allows producing electron bunches with duration of 50 ps, energy of about 3 MeV and the energy spread of about 5%.
	Poster TUPSA068 [0.996 MB]
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TUPSA069	Optimization of an RF Probe Vicinity for RF Gun Cavities	348
	V.V. Paramonov RAS/INR, Moscow, Russia
	To provide electron bunches with exceptionally high brightness, RF gun cavity should operate with the extreme electric and magnetic fields. The RF probe is required for the mostly reliable and precise measurements of the RF field phase and amplitude directly from the cavity. The implementation of an RF probe in the cavity design generates a set of coupled problems, which is analyzed and compared for different operating frequencies and different RF pulse length. Both general dependencies and particularities are considered. Some recommendations for practical choice of the RF probe are presented.
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WEPSB074	High Current Pulsing Deuteron Accelerator with Energy of 500 keV	527
	A.A. Isaev, K.I. Kozlovskiy, A.E. Shikanov, E.D. Vovchenko MEPhI, Moscow, Russia
	It is reported on the development of a compact experimental model of the deuteron accelerator with energies up to 400 KeV. The ion current is about 1 kA and the current density is greater than 20 A/cm² in pulses with a duration of 0.5 mks and a repetition rate of 1 Hz. In this accelerator, we applied the effective ion source of laser-plasma and the optimized method of magnetic insulation of the electrons in the accelerating gap.
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THPSC073	Development of the Hardware-Software Complex PIRS-5 for Field Measurements in Accelerating Structures	702
	G.S. Pomogaybo, M.V. Lalayan, S.E. Toporkov MEPhI, Moscow, Russia
	Hardware-software complex "PIRS-5" was developed to make measurements in warm accelerating structures. The idea was to create full-automatic measuring system, which can measure electrical field at the bead position with non-resonant and resonant pull techniques. PIRS-5 has postprocessor, which calculate electrical component from the frequency, reflection or transmission coefficient, shunt and effective shunt impedance. This work describes the construction of this complex, its mathematical part and possible future modifications.
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Paper

Title

Page

Recent Optimized Design of ILC Cryomodule With Explosion Welding Technology

141

B.M. Sabirov
JINR, Dubna, Moscow Region, Russia

Primary purpose of this experiment is the development of techniques to simplify and make cheaper the construction of the cryomodules. In the current ILC TDR design the helium vessel and the connected pipes are made of expensive titanium. JINR in association with INFN several designs for these transitions have been produced and studied during the last years. The results of measuring microhardness by Vickers microindentation are issued of ~3.8 GPa and the breaking strength was 375 MPa. Helium leak measurements revealed no leaks at a background leak rate of 0.4*10^-10 atm*cc/s. For imitation of use transition sample in real working position, connected with Nb cavity, Nb rings were joint with Nb pipe of samples by EBW. Superposition of all residual stresses may result plastic deformation, failure of welds, and consequently occurrence of a leak. Test result of thermocycles in LHe and in the LN ussued absence of leak at background leak rate ~0.5*10^-10 atm*cc/sec. The results showed the full eligibility of suggested design Nb+Ti+SS transition sample not for only Linear Collider, but for any cryogenic systems.

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TUCBSH01

Next Generation High Power Solid-State RF Sources

G.B. Sharkov, T.V. Bondarenko, A.A. Krasnov, S.A. Polikhov
NIITFA, Moscow, Russia

Solid-state RF power amplifier (SSPA) technology has developed significantly over recent years. Powers of hundreds of kilowatts are being achieved, driven by the developments of LDMOS and other transistor technologies. The price and size of SSPA still correlate with the output power, which is not the case for vacuum tube based devices. In order to be competitive with vacuum tubes at higher levels of power and frequency, SSPA's should be designed to be more compact and cheaper than current offerings, using the high efficiency and reliability of modern transistors to produce highly available amplifier systems. The scalability of SSPA output power is achieved by a modular architecture based on several ~1kW transistors; this gives an important advantage over vacuum tubes. In order to meet challenging demands for high power, efficient, reliable, compact and cost effective RF amplifiers, the next generation architecture of SSPA is employed and single design for various frequencies and power is proposed.

Slides TUCBSH01 [7.332 MB]

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THXSH01

Development of the INR Linear Accelerator DTL RF System

191

A.I. Kvasha, V.L. Serov
RAS/INR, Moscow, Russia
A. Feschenko
MIPT, Dolgoprudniy, Moscow Region, Russia

The regular INR DTL RF system operation began in 1992. By this point three new type of vacuum tube, designed purposely for INR linear accelerator, were manufactured at OKB "Swetlana" in the amount sufficient for RF system operation during 20 years. Among them were two vacuum tubes for final RF power amplifier - GI-54A and RF driver - GI-51A and also vacuum tube for powerful anode modulator - GMI-44A. In the late 80s manufacture of these vacuum tubes was stopped and since 1990 designing of new vacuum tube for RF output power amplifier instead of GI-54A was started. The new vacuum tube GI-71A with output RF power up to 3 MW in pulse, plate power dissipation up to 120 kW and power gain about 10 was simpler and less expensive in comparison with GI-54A. The transition to new vacuum tube began in 1999 and finished in 2014. Successful testing of GI-57A as RF driver, fulfilled in 2008, opened the possibility of replacement GI-51A. As for GMI-44A replacement there are no analogues, produced in Russian federation, and, as it turned out, the only option was GI-71A again. Below some problems, connected with the vacuum tubes replacement, as well as main results of twenty years DTL RF system operation are considered.

Slides THXSH01 [4.748 MB]

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THXSH02

Three Transverse Deflecting Systems for Electron Beam Diagnostics in the European Free-Electron Laser XFEL

196

A.A. Zavadtsev
RAS/INR, Moscow, Russia

Funding: European XFEL GmbH, Ministry of Education and Science of Russia
In frames of Russian in-kind contribution to Europe-an XFEL, INR in cooperation with DESY is responsible for Transverse Deflecting Systems (TDS) for special beam diagnostic in the XFEL linac. Three TDS have been developed: TDS INJ in the Injector, TDS BC1 in the Accelerator tunnel after Bunch Compressor 1 and TDS BC1 after Bunch Compressor 2. Each system in-cludes S-band disk-loaded deflecting structure (DLS), waveguide system, klystron, pulse transformer, modu-lator and control system. TDS INJ has been built, as-sembled in the Injector building and tested. It is used to monitor the bunch length, longitudinal phase space and slice emittance now. Exceptionally small, exceed-ing expectations, slice emittance of electron bunch was measured using TDS INJ during the XFEL Injector commissioning. Three structures for TDS BC1 and TDS BC2 as well as the waveguide systems have been built, tested and TDS BC2 part installed in the XFEL tunnel.
On behalf of the joint XFEL TDS team

Slides THXSH02 [16.400 MB]

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THCASH01

Effective RF Deflecting Structures for Bunch Rotation and Deflection

201

V.V. Paramonov
RAS/INR, Moscow, Russia

Deflecting RF Structures find now applications for the bunch rotation with the purposes of diagnostic for the longitudinal distribution, emittance exchange and for the luminosity improvements in colliders. Report describes results of R&D program for development of deflectors with minimized level of aberrations in the distribution of deflecting field. Such structures, applied for bunch rotation along transverse axis, provide much smaller emittence growth, as compared to another options. In comparison with classical and widely used deflectors, based on disk loaded waveguide, developed structures have, depending on modification, in 2-6 times higher RF efficiency. Structures can operate both in Traveling Wave (TW) and in Standing Wave (SW) modes. To create long RF cavities for SW operation, compensated (bi-periodical) options are developed, combining field stability and high RF efficiency. The problem of stabilization for the plane of deflection is removed due to essentially 3D geometry. The main solutions for such structures development are described and achieved parameters are reported.

Slides THCASH01 [6.084 MB]

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TUPSA027

The Study of the Helical RF Resonator for the 300 keV Nitrogen Ion CW Implanter

270

N.V. Avreline
TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada
P.G. Alexey, S.M. Polozov
MEPhI, Moscow, Russia

The helical RF resonator for the single charged 300 keV nitrogen ion CW implanter was designed, simulated in CST Microwave Studio and the results were experimentally verified. The current setup of the implanter is described as well as possible modifications to accelerate ions of other types. The results of the field distribution's RF measurements and the results of the high-power test are also presented.

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TUPSA029

High Power Solid State RF Generator for Neutral Beam Injector

276

E. Shubin, V.V. Kolmogorov
BINP SB RAS, Novosibirsk, Russia
A.S. Styuf
NSU, Novosibirsk, Russia

Neutral Beam Heating Injector of 1 MW beam power for the TCV tokamak (Lausanne, Switzerland) was developed in BINP. The plasma is formed in a plasma box with inductively coupled RF power at frequency about 4 MHz. Required RF power in the plasma box is up to 40 kW during the period of 2 seconds with 5 minutes intervals. Solid state RF generator with such capability has been developed in BINP. The generator has a modular structure with combining RF power of 16 identical modules. Output RF power of the generator is regulated by DC power supply voltage. At present Injector is working at TCV. Description of the RF generator design, main features and the test results are presented in the report.

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TUPSA030

Regulation of the Waveguide Coupling Factor of Standing Wave Linear Accelerator

279

D.S. Yurov
MSU, Moscow, Russia
V.I. Shvedunov
LEA MSU, Moscow, Russia
V.I. Shvedunov
SINP MSU, Moscow, Russia

Regulation of the waveguide coupling factor of standing wave linear accelerator allows to adjust the value of accelerated current, keeping the reflected RF power close to zero. This ensures the most efficient use of RF energy and absence of overvoltage in the waveguide elements. The paper presents studies results for various methods of coupling factors regulation with continuous wave (CW) normal conducting linear accelerator used as an example. The results of calculations and measurements on the mock-up of the accelerating structure are presented.

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TUPSA031

The Cascade Interference Switch Comprising a Transmission Resonator

282

S.A. Gorev, S.N. Artemenko, V.S. Igumnov
TPU, Tomsk, Russia

The new concept of microwave interference switches is reported. Interference switch is based on series of H-plane T-junctions (cascade switch) in the view of decreasing switched power at Off state and comprises irises in both its own input and output arms. At On state the irises act as a transmission resonator localizing the nodes of the standing wave at the junctions. Such distribution is expected to decrease the plasma losses. It was shown with a simulation that the cascade switch with additional irises increases the efficiency of the active microwave compressors. The simulation was made with CST studio and COMSOL.

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TUPSA032

Input Coupler Design for IH-Based Accelerating Structure

S.E. Toporkov, A.S. Bogomolov, M.V. Lalayan, G.S. Pomogaybo
MEPhI, Moscow, Russia

Design of the input/output couplers for Interdigital H-mode (IH) proton accelerating structures operating in travelling wave regime has a range of tasks to be solved. Most of the difficulties are caused by low working frequency band which is far below the cutoff frequency of the cylindrical waveguide. To get an appropriate coupling with the slow-wave structure a coaxial coupler design is considered. Reduction of reflected harmonic and coupler matching is performed by end-cell geometry modification. Two types of accelerating structure: classical IH-structure and modified compact version are considered. Both have 433MHz operating frequency. Results of the main electrodynamic characteristics, end-cell optimization and thermal heating for different power levels are presented.

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TUPSA034

520 MeV TRIUMF Cyclotron RF System: Maintenance, Tuning and Protection

285

N.V. Avreline, T. Au, I.V. Bylinskii, B. Jakovljevic, V. Zvyagintsev
TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada
C.D. Bartlett
University of Victoria, Victoria BC, Canada

Funding: TRIUMF receives federal funding via a contribution agreement through the National Research Council of Canada.
1 MW CW 23 MHz RF system of the TRIUMF's 520 MeV Cyclotron has been in operation for over 40 years. Continuous development of the RF power amplifiers, the waveguide system and the measurement and protection devices provides reliable operation and improves the performance of the RF System. In this article, operation and maintenance procedures of this RF system are analysed and recent as well as future upgrades are being analysed and discussed. In particular, we discuss the improvements of the transmission line's VSWR monitor and its effect on the protection of the RF system against RF breakdowns and sparks. We discuss the new version of the input circuit that was installed, tested and is currently used in the final stage of RF power amplifier. We analyse various schematics and configurations of the Intermediate Power Amplifier (IPA) to be deployed in the future.

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TUPSA035

Estimation of Multipacting in CDS Structure

288

I.V. Rybakov
RAS/INR, Moscow, Russia
I.I. Isaev
DESY Zeuthen, Zeuthen, Germany

The Cut Disk Structure (CDS) is recommended for replacement of the first cavity of the main part of INR linac. For the cavity work stability there should be no multipactor at operating regime. CDS structure was first set on exploitation at DESY PITZ electron linac. For this cavity according to the analytical estimation multipaction should appear at the operating power level in coupling cells, but it was not approved by the numerical simulation with both accelerating and coupling modes excitation for RF energy transfer along the cavity. The multipactor appears only with the secondaty emission yield (SEY) growth which could happen if the inner surface of the cavity is polluted. The results of multipactor investigation in CDS PITZ were used as reference for the CDS structure for the first cavity of the main part of INR linac. The analytical estimation and numerical simulation of multipactor in CDS INR structure shows the appearance of the discharge in coupling cells with the OFC copper SEY for the operating regime of the cavity. An option for the multipactor damping with the forced excitation of oscillations in coupling cell with voltage higher than upper multipactor limit was considered.

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TUPSA036

Manufacturing Tolerances Estimation for Proton Linac Cavities

291

I.V. Rybakov, V.V. Paramonov, A.K. Skasyrskaya
RAS/INR, Moscow, Russia

The definition of manufacturing tolerances is one of the stages of accelerating structure construction. In case of proton linacs the value of accelerating field homogeneity is a critical parameter. It depends both on cells frequencies perturbations and the coupling coefficient perturbations. These values could be obtained using the numerical simulations of the characteristic electromagnetic oscillations in the cell. There is the method that allows the reduction of the simulations time and to avoid separate simulations for each geometrical parameter of the structure. This method was improved and extended for the pi/2-wave, pi-wave and travelling wave structures. Several examples of the method application, including the structure for the first cavity of the main part of INR linac, are presented.

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TUPSA037

Powerfull RF Triode as Anode Modulator Vacuum Tube

294

A.I. Kvasha, V.L. Serov
RAS/INR, Moscow, Russia

For 20 years modulator vacuum tube GMI-44A successfully operated in DTL RF system of INR Linac. The vacuum tube had been designed and manufactured at OKB "Swetlana" in the 70s-80s of the last century. The quantity of manufactured tubes - about 80, had allowed the accelerator operating till now. Manufacture of the tubes was stopped In the mid 80s. Attempts of the GMI-44A manufacture restoration or repair were unsuccessful ones. As it turned out, the only decision in the circumstances was using of 200 MHz powerful pulse triode GI-71A as modulator tube. The vacuum tubes GI-71A were installed for the last ten years in all output RF power amplifiers (PA) of INR Linac instead of RF pulse triode GI-54A. In the paper some problems appearing after modulator vacuum tube replacement are discussed.

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TUPSA038

The RF Power System for RFQ-Injector of Linac-20

297

V.G. Kuzmichev, A.V. Kozlov, T. Kulevoy, S.M. Polozov, D.N. Selesnev, Yu. Stasevich
ITEP, Moscow, Russia
A.V. Butenko
JINR, Dubna, Moscow Region, Russia
T. Kulevoy, S.M. Polozov
MEPhI, Moscow, Russia

In the frame of the Nuclotron-M project the electrostatic injector of LU-20 is replaced by a RFQ accelerator, which has been developed in ITEP. The construction of 400 kW, 145 MHz RF system for RFQ-injector are described. Pa-rameters and test results of the RF power system operated on the resistive load and on RFQ during ion beam accele-ration are presented

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TUPSA046

Experimental Analysis of Dipole Modes in Elliptical Cavity

313

Ya.V. Shashkov, M.V. Lalayan, N.P. Sobenin
MEPhI, Moscow, Russia
A. Orlov
NRNU, Moscow, Russia

The experimental measurements of transverse shunt impedance for higher order modes TM110 and TE111 for S-band elliptical cavity were carried out. The experiments using dielectric and metallic spheres as perturbing objects and with ring probe were done.

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TUPSA068

Simulation of S-Band RF Gun with RF Beam Control

345

A.M. Barnyakov, A.E. Levichev, D.A. Nikiforov
BINP SB RAS, Novosibirsk, Russia
M.V. Maltseva
NSU, Novosibirsk, Russia

The design and operation of electron RF gun with RF beam control are described. Results of numerical simulation of electromagnetic fields and beam dynamics are presented. RF gun consists of two resonators operating at E010 mode with 180 degrees phase shift at frequency of 2856 MHz. RF control is carried out via coaxial resonator with grid-cathode capacity. Accordint to result of the simulation, RF gun with RF control allows producing electron bunches with duration of 50 ps, energy of about 3 MeV and the energy spread of about 5%.

Poster TUPSA068 [0.996 MB]

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TUPSA069

Optimization of an RF Probe Vicinity for RF Gun Cavities

348

V.V. Paramonov
RAS/INR, Moscow, Russia

To provide electron bunches with exceptionally high brightness, RF gun cavity should operate with the extreme electric and magnetic fields. The RF probe is required for the mostly reliable and precise measurements of the RF field phase and amplitude directly from the cavity. The implementation of an RF probe in the cavity design generates a set of coupled problems, which is analyzed and compared for different operating frequencies and different RF pulse length. Both general dependencies and particularities are considered. Some recommendations for practical choice of the RF probe are presented.

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WEPSB074

High Current Pulsing Deuteron Accelerator with Energy of 500 keV

527

A.A. Isaev, K.I. Kozlovskiy, A.E. Shikanov, E.D. Vovchenko
MEPhI, Moscow, Russia

It is reported on the development of a compact experimental model of the deuteron accelerator with energies up to 400 KeV. The ion current is about 1 kA and the current density is greater than 20 A/cm² in pulses with a duration of 0.5 mks and a repetition rate of 1 Hz. In this accelerator, we applied the effective ion source of laser-plasma and the optimized method of magnetic insulation of the electrons in the accelerating gap.

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THPSC073

Development of the Hardware-Software Complex PIRS-5 for Field Measurements in Accelerating Structures

702

G.S. Pomogaybo, M.V. Lalayan, S.E. Toporkov
MEPhI, Moscow, Russia

Hardware-software complex "PIRS-5" was developed to make measurements in warm accelerating structures. The idea was to create full-automatic measuring system, which can measure electrical field at the bead position with non-resonant and resonant pull techniques. PIRS-5 has postprocessor, which calculate electrical component from the frequency, reflection or transmission coefficient, shunt and effective shunt impedance. This work describes the construction of this complex, its mathematical part and possible future modifications.

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