RuPAC2014 - List of Keywords (cavity)

Paper	Title	Other Keywords	Page
TUCB02	RF System of the Booster of NICA Facility	controls, booster, acceleration, feedback	26
	G.Y. Kurkin, A.M. Batrakov, G.A. Fatkin, Ya.G. Kruchkov, S.A. Krutikhin, S.V. Motygin, A.M. Pilan BINP SB RAS, Novosibirsk, Russia G.A. Fatkin NSU, Novosibirsk, Russia
	The project NICA is being constructed in JINR, Dubna to provide collisions of heavy ion beams in the energy range from 1 to 4.5 GeV/u at the luminosity level of 110²⁷ cm^-2s⁻¹. One of the elements in the collider injection chain is BUSTER – a cycling accelerator of ions 197Au³²⁺. The injection energy of particles is 6.2 MeV/u, extraction energy is 600 MeV/u. Two RF stations are to provide 10 kV of acceleration voltage. Frequency range of operation of the stations in the injector chain is from 634 kHz to 2400 kHz. The provisions are made for autonomous mode of operation of the stations in the frequency range of 0.5 – 5.5 MHz at the same accelerating voltage. Amorphous metal rings of Russian production are used in the RF cavities. RF stations are created in the Budker Institute of Nuclear Physics, SB RAS, Novosibirsk. The stations are tested in the operative mode and will be delivered to the customer in October, 2014. Main design features and parameters of RF cavity, power generator and control system of the stations are described in the paper.
	Slides TUCB02 [1.265 MB]

TUPSA09	Beam Dynamics Calculations in the Multi-Beam Generator Cavity	electron, controls, impedance, klystron	54
	E.A. Savin, S.V. Matsievskiy, N.P. Sobenin MEPhI, Moscow, Russia A.A. Zavadtsev Nano, Moscow, Russia
	In the previously designed, calculated and tuned structure of the compact generator-cavity the beam dynamics for the different geometry options has been calculated. The influence of injected beam parameters to the output power value has been overviewed. Also the geometry of the beam tubes and couple coefficient between cavity and the output waveguide has been optimized to reach the maximum output power value.

TUPSA18	Complex Shunt Impedance and Beam-RF Cavity Interaction	impedance, damping, experiment, resonance	77
	V.G. Kurakin LPI, Moscow, Russia
	Two approaches usually are used to describe beam-cavity interaction in accelerator based applications. The first one is electro dynamical and uses Maxwell equations to derive appropriate equations, field modes expressions being necessary to calculate field amplitudes excited by moving charges in the cavity. The other one uses LC circuit to derive appropriate equations for voltage amplitude induced in cavity by accelerated bunches, thin accelerating gap to some extent being not fully correctly defined representation in such approach. In this paper, the expressions are derived that describe beam-RF cavity interactions in terms of so called complex shunt impedance, strict electro dynamical approach being used in calculations. It is shown that complex shunt impedance module coincides completely with usual shunt impedance definition that up to now is used widely to describe rf cavity efficiency. The physical sense of its phase is given in the paper as well. Both complex shunt impedance module and its phase can be calculated or measured experimentally.

TUPSA20	Output Energy Variation in the SC Linac for the Proton Radiotherapy	simulation, linac, proton, focusing	80
	I.A. Ashanin, S.M. Polozov, A.V. Samoshin MEPhI, Moscow, Russia
	Current success of the superconducting linear accelerators based on independently phased SC cavities gives a seriously reason to consider such structure in proton radiotherapy. Superconductivity allow to solve at once some problems concerned with a low rate of energy gain, high length, higher capacity losses and higher cost of the proton linear accelerator subsequently. One of the traditional aims of such facilities is receiving of the beam energy about 240 MeV with possibility of fluently regulation in range from 150 to 240 MeV that responds to irradiate the tumors located at different depth. The possibility of beam energy variation by means of RF field phase in last resonators and number of the resonator turn-off becomes the major advantage of the proton SC linac. The optimal choice of accelerator parameters and the beam dynamics simulation results with using BEAMDULAC-SCL code will presented. Methods of the output energy variation with beam quality preservation in the proton SC linac will discussed. A.V. Samoshin. Proc. of LINAC2012, Tel-Aviv, Israel, TUPB069, p. 630 - 632

TUPSA26	Electrodes Form Optimization of RF Deflecting System Wobbler for FAIR Project	heavy-ion, ion, target, experiment	91
	A. Sitnikov, A. Golubev, T. Kulevoy, S.A. Visotski ITEP, Moscow, Russia
	Funding: SAEC "Rosatom" and Helmholtz Association The new method for high energy density states in matter investigation, which based on irradiation of combined target by hollow high energy heavy ion beam was proposed in the Institute for theoretical and experimental physics (ITEP). The target consists of a sample of matter at the center and a hollow shell around it. The experiment of high energy density states generation will be carry on at FAIR project. The RF deflecting system (Wobbler) for hollow high energy heavy ion U²⁸⁺ beam with kinetic energy Wk=1 GeV/n formation is developing at ITEP. The current results of electrodes form optimization for RF deflecting system (Wobbler) which is developing at ITEP for FAIR project are shown in this paper.

WEPSB04	Field Optimization Technique of the Multigap H-mode Resonators	impedance, linac, acceleration	162
	S.E. Toporkov, A.B. Buleiko, M.V. Lalayan MEPhI, Moscow, Russia
	Optimization of the H-mode resonators requires uniform accelerating field distribution on its axes. To realize this task pylons with the holes on its end walls are used in many cases. During applying this technique in case of cavities with low number of periods it was mentioned that the best value of the field flatness was obtained in case of zero gap between end walls of the resonator and the pylon. It means that each pylon has got the electrical contact with one of the end walls of the resonator. For such cavity geometry magnetic field distribution differs from the classical H – resonator: it transforms in one common magnetic flux like in split-coaxial cavities. The analysis of such structures was performed for two types of H-mode resonators: Cross bar H-mode (CH) resonators with working frequency 324MHz and Interdigital H-mode (IH) resonators with working frequency 162MHz. All types of resonators work on the pi-mode and have 9 accelerating gaps. The main stages of E-field flatness optimization inside CH⁻ and IH⁻ cavities are presented at this paper.

WEPSB05	Optimization of Electric Field Distribution Inside Multi-gap CH-Resonator	impedance, proton, acceleration, rfq	164
	S.E. Toporkov MEPhI, Moscow, Russia
	This paper presents the results of the electrodynamic modelling of the Crossbar H-mode (CH) resonator. The main goal was to get the uniform accelerating field distribution and to optimize effective shunt impedance. The initial model of the 324 MHz cavity consists of 7 equidistant RF gaps with the period length 46.26 mm. To optimize its electrodynamic characteristics the design contains pylons. Solution of the tuning task consists of several steps. Firstly it was chosen the optimal relation between the holding rod length and the pylon's height. Then the most significant improvement on the E-field distribution was introduced by optimizing the gap between end walls of the resonator and the pylon. The final adjustment of the field distribution and the tuning to the working frequency was performed by means of the holes in the pylon. Correct geometry increases effective shunt impedance from 55 MOhm/m to 80 MOhm/m and improves the field flatness to the 97%. The results of optimization the cavities for different particle velocities with 7,9 and 11 accelerating gaps and different aperture diameter are presented.

WEPSB06	The Optimization of the Buncher at 145.2 MHz to Reduce Multipactor Effect	simulation, electron, injection, beam-transport	166
	M. Gusarova, T. Kulevoy, I.I. Petrushina, A.S. Plastun, S.M. Polozov MEPhI, Moscow, Russia T. Kulevoy, A.S. Plastun ITEP, Moscow, Russia
	The results of the optimization of the cavity of the single gap buncher at 145.2 MHz to reduce multipacting effect are presented. Resonant voltages, impact energies and corresponding particle trajectories are obtained. The variants of design to reduce multipacting effect are considered.

WEPSB08	Multi-beam Generator Cavity for the Proton Linear Accelerator Feeding System on 991 MHz Frequency Geometry Optimization	coupling, impedance, proton, electron	171
	E.A. Savin, S.V. Matsievskiy, N.P. Sobenin MEPhI, Moscow, Russia A.A. Zavadtsev Nano, Moscow, Russia
	For the proton linear accelerator feeding system 800 kW input power value is required. The system consists from pillbox cavity with six beam tubes connected to the rectangular waveguide as a power output system is designed. In case of using high voltage gun with modulated six-bunch injection, this system allows to transform the energy of electron bunches which flies throw beam tubes to accelerating section feeding power. Different types of the structure geometry were calculated. The whole structure consists both from generator cavity and accelerating structure has been designed.

WEPSB12	Cascade Interference Switches for Active Microwave Compressors	operation, extraction, experiment, distributed	180
	S.A. Gorev, S.N. Artemenko, V.A. Avgustinovich, V.S. Igumnov, V.L. Kaminski, S.A. Novikov, Yu.G. Yushkov TPU, Tomsk, Russia
	Funding: "Science" state order of the Russian Ministry of Education and Science. Results of study energy extraction devices for S-band microwave pulse compressors are presented. The devices are manufactured as interference switches produced from the circular single mode waveguide and that are differs only by the cascade of identical H-plane T-junctions connected in series at a side arm of H-tee. The versions cascade switches which are matched and unmatched from the side of auxiliary arm of T-junction are investigated. It is shown the variant of cascade switches with the matched T-junctions allows decrease the switching power level few times comparatively the switching power of usual one. Possibility of increasing operation power and stability of output pulses of microwave pulse compressors with such energy extraction devices are confirmed in experiments. There are presented the results of investigation the cascade including two and three switches connected in series by straight arms. It is shown the switching power level for such type cascade switches can be many less than for usual switch with one T-junction. Results of experimental study cascade switches of such type confirming with the results of the theoretical analyses are presented and peculiarities of cascade switches are mentioned. The assumption about good perspectives for the cascade switches manufactured from oversized rectangular waveguide is formulated. The obtained results concerning of the cascade switch operation have been demonstrated the possibility of increasing switch operation power.

WEPSB13	Oversized Interference Switches of Active Microwave Pulse Compressors	extraction, coupling, operation, plasma	183
	V.S. Igumnov, S.N. Artemenko, V.A. Avgustinovich, S.A. Gorev, V.L. Kaminski, S.A. Novikov, Yu.G. Yushkov TPU, Tomsk, Russia
	Funding: "Science" state order of the Russian Ministry of Education and Science. Results of simulation and experimental study of two types of the oversized interference switches are presented. The switch of the first type was developed on basis of the simulation of the oversized rectangular waveguide H-tee with the H01 operation mode. Conditions of effective operation of the first type switch as an energy extraction element of active microwave pulse compressors are determined. The output pulse power of 2.8 MW and pulse width of 3.5 ns with the corresponding amplification factor of 17.5 dB for were obtained in the X-band microwave pulse compressor prototype containing the storage cavity made of WR-284 waveguide and the switch made of the waveguide with the cross section area of 58×25 mm2. The results of experimental study of the oversized X-band interference switch of the second type with the synchronous energy extraction through a compact packet of common single mode switches incorporating the five identical waveguide tees are presented as well. Possibility of full synchronization of the switch packet is proved and the conditions of such synchronization are determined. Permissible quantity of the switches in a packet unit is estimated. The output pulse power of 0.8 MW, pulse width of 3.2 ns at the power gain of 12 dB and the pulse power of 2.2 MW, pulse width of 3.5 ns at the power gain of 16.5 dB were obtained when the energy extraction from the five different single mode resonant cavities and an oversized cavity respectively was synchronous.

THX02	Experience in Research, Development, Construction and Commissioning of Normally Conducting Accelerating Structures	linac, coupling, HOM, simulation	278
	V.V. Paramonov, L.V. Kravchuk RAS/INR, Moscow, Russia
	The experience and results of research, development, construction and start of normally conducting accelerating structures for high intensity hadron linear accelerators at medium and high energii is summarized Created methods and obtained results provided construction and start of operation of accelerating system in INR H⁻ linac with designed energy 600 MeV. The research results allow generalize the properties of high energy structures and develop methods and criteria for improvements, with were realized in the development and commissioning of accelerating structures in another foreign laboratories. Basing on research results, the high energy accelerating structure, which surpasses analogues in the total list of parameters, is proposed and approved.
	Slides THX02 [1.259 MB]

THCE02	CW 100 keV Electron RF Injector for 40 mA Average Beam Current	cathode, gun, electron, vacuum	309
	V. Volkov, V.S. Arbuzov, K.N. Chernov, E.I. Kolobanov, S.A. Krutikhin, E.A. Kuper, I.V. Kuptsov, G.Y. Kurkin, S.V. Motygin, V.N. Osipov, V.K. Ovchar, V.M. Petrov, V.V. Repkov, M.A. Scheglov, I.K. Sedlyarov, G.V. Serdobintsev, S.S. Serednyakov, S.V. Tararyshkin, A.G. Tribendis BINP SB RAS, Novosibirsk, Russia I.V. Shorikov RFNC – VNIIEF, Sarov, Russia A.V. Telnov, N.V. Zavyalov VNIIEF, Sarov, Russia
	CW 100 keV electron RF gun for 40 mA average beam current was developed, built and commissioned at BINP SB RAS. The RF gun consists of normal conducting 100 MHz RF cavity with a gridded thermo cathode unit, CW 16 kW generator with GU-92A tetrode in the output stage and a set of LLRF electronics. The gun was tested up to the design specifications at a test bench that includes a diagnostics beam line. The design features of different components of the gun are presented. Preparation and commissioning experience is discussed. The beam test results are summarized.

THPSC03	Study of Superconducting Accelerating Structures for Megawatt Proton Driver Linac	linac, simulation, accelerating-gradient, proton	318
	S.M. Polozov, K.A. Aliev, A.M. Fadeev, M. Gusarova, T. Kulevoy, M.V. Lalayan, N.P. Sobenin, O. Verjbitskiy MEPhI, Moscow, Russia
	Funding: This project was supported by the Ministry of Science and Education of Russia under contract No. 14.516.11.0084 The preliminary design of megawatt level proton accelerator-driver is carrying out by collaboration between Russian scientific centers MEPhI, ITEP, Kurchatov Institute. This project was supported in 2013 by the Ministry of Science and Education of Russia. The linac general layout includes SC Spoke-cavities at middle energy range and elliptical cavity at high energy one. The usage of QWR and/or HWR at 10-30 MeV was also discussed. Due to electrodynamics models of all structures types were designed and the electrodynamics characteristics were studied. QWR, HWQ and Spoke-cavities were proposed to operate on 324 MHz and elliptical cavities on 972 MHz. The main electrodynamics simulation results will present in report. The multipactor study results will also discussed.

THPSC04	Study of Normal Conducting Accelerating Structures for Megawatt Proton Driver Linac	rfq, linac, Windows, coupling	321
	S.M. Polozov, A.E. Aksentyev, A.A. Kalashnikova, T. Kulevoy, M.V. Lalayan, S.E. Toporkov MEPhI, Moscow, Russia
	Funding: This project was supported by the Ministry of Science and Education of Russia under contract No. 14.516.11.0084 The preliminary design of megawatt level proton accelerator-driver is carrying out by collaboration between Russian scientific centers MEPhI, ITEP, Kurchatov Institute. This project was supported in 2013 by the Ministry of Science and Education of Russia. The linac general layout includes RFQ section and section(s) with radiofrequency focusing. The different types of RF focusing were studied due to this project: RF crossed lenses, modified electrodes RFQ, axi-symmetrical RF focusing. All such focusing can be realized by IH-type cavities. The design of segmented vane RFQ (SVRFQ) with coupling windows and IH⁻ and CH-type normal conducting cavities will discuss in the report. All cavities operate on 162 MHz. The main electrodynamics simulation results will present.

THPSC16	Analysis of High Order Modes Damping Techniques for 800 MHz Single Cell Superconducting Cavities	HOM, damping, dipole, luminosity	353
	Ya.V. Shashkov, N.P. Sobenin MEPhI, Moscow, Russia M. Zobov INFN/LNF, Frascati (Roma), Italy
	Funding: Research supported by RFBR grant 13-02-00562/14 and EU FP7 HiLumi LHC - Grant Agreement 284404 The High Luminosity LHC upgrade program foresees a possibility of using the second harmonic cavities working at 800 MHz for the collider bunch length variation. Such harmonic cavities should provide an opportunity to vary the length of colliding bunches. In order to supply the required harmonic voltage several single cell superconducting cavities are to be used. Different cavity designs and several higher order mode (HOM) damping techniques are being studied in order to reduce the cavity HOM impact on the beam stability and to minimize parasitic power losses. In this paper we analyze and compare the HOM electromagnetic characteristics and respective wake potential decay rates for cavities with grooves, fluted and ridged beam pipes. The problem of Lorentz force detuning is also addressed.

THPSC17	Higher Order Modes Damping for 9-cell Structure with Modified Drift Tubes	HOM, damping, quadrupole, dipole	356
	Ya.V. Shashkov, A.A. Mitrofanov, N.P. Sobenin MEPhI, Moscow, Russia V. Zvyagintsev TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada
	Funding: Research supported by RFBR grant 13-02-00562/14 This paper is focused on HOM damping in 9-cell superconducting cavities. We are considering HOM propagation outside from the cavity ridged and fluted drift tubes. The analysis of the influence of the parameters of the drift tube on the HOM damping was conducted. The considered methods were analysed and compared.

THPSC18	Suppression of Mechanical Oscillations in Quarterwave 10⁶ MHz Resonator	simulation, niobium, TRIUMF, superconductivity	359
	M. Gusarova, I.I. Petrushina, I.V. Rybakov, Ya.V. Shashkov, Ya.V. Shashkov, V. Zvyagintsev MEPhI, Moscow, Russia V. Zvyagintsev TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada
	Analytical calculations and numerical simulations have been done for mechanical eigenmodes of quarter wave superconducting resonators with operating frequency of 10⁶ MHz and 80 MHz. A possibility of frequency shift of mechanical modes in 106 MHz resonator has been estimated by application of the damper. We have optimized the damper's position for suppression efficiency. We have also compared the numerical and experimental results.

THPSC19	Influence of the Different Geometric Parameters of Superconducting Elliptical Cavities on the Multipactor	accelerating-gradient, electron, simulation, multipactoring	362
	M. Gusarova, I.I. Petrushina MEPhI, Moscow, Russia
	The results of numerical simulations of multipacting in the different superconducting elliptical cavities are presented. Question of influence of the aperture radius, equator shape, iris shape and frequency and electron trajectories for different geometrical parameters of elliptic structures are considered.

THPSC20	Multipactor in Elliptical Cavities 800 MHz	electron, damping, HOM, resonance	365
	M. Gusarova, I.I. Petrushina MEPhI, Moscow, Russia
	The studies of the multipacting discharge possibility in elliptic single-cell cavities at 800 MHz with three types of hifger order modes couplers were done. The ranges of the field gradients where the conditions for the occurrence of first order multipacting discharge in the equatorial region, as well as the HOM field levels were determined.

THPSC33	Digital Signal Processing Algorithms for Linac Low-Level RF Systems	FPGA, controls, operation, embedded	392
	D.A. Liakin, S.V. Barabin, A.Y. Orlov ITEP, Moscow, Russia
	A set of LLRF systems had been designed for various applications of resonant RF devices such as accelerators or beam deflectors. This report presents compact signal detection algorithms, used in most of developed systems. Application-specific extension of the signal processing procedure allows the system be synchronized to external self-excited oscillator.
	Poster THPSC33 [13.540 MB]

THPSC50	Neutron Accelerating Tubes with Microwave Deuterons Source Using Electron-cyclotron Resonance Effect	neutron, ion, plasma, ECR	441
	A.N. Didenko, B.Y. Bogdanovich, K.I. Kozlovskiy, A. Nesterovich, A.V. Prokopenko, V.L. Shatokhin, A.E. Shikanov MEPhI, Moscow, Russia
	The physical principles of increased efficiency neutron accelerating tubes based on the microwave sources of heavy hydrogen nuclides, using the electron-cyclotron resonance effect (ECR) are considered. The authors' theoretical results are given on electromagnetic oscillations generation in the working volume of the ion source of the accelerating tube with the boundary excitation of a microwave discharge. Resonator and waveguide modes for ECR-plasma excitation are thus examined. Features of neutron generation in these accelerator neutron tubes based on microwave source of heavy hydrogen nuclides are analyzed. The algorithm is developed and numerical simulation of neutron pulse formation in neutron generators based on microwave source is done taking into account target shape and the possible deuterons resonant recharge. Frequency dependences of the energy flux density transmitted from an alternating electromagnetic field to the electron component of the plasma are obtained depending on the constant longitudinal magnetic field induction and pressure in the discharge chamber. The results of these studies could form the basis for the efficient domestic portable neutron generators development based on accelerating tubes with microwave hydrogen nuclides sources.

Paper

Title

Other Keywords

Page

TUCB02

RF System of the Booster of NICA Facility

controls, booster, acceleration, feedback

26

G.Y. Kurkin, A.M. Batrakov, G.A. Fatkin, Ya.G. Kruchkov, S.A. Krutikhin, S.V. Motygin, A.M. Pilan
BINP SB RAS, Novosibirsk, Russia
G.A. Fatkin
NSU, Novosibirsk, Russia

The project NICA is being constructed in JINR, Dubna to provide collisions of heavy ion beams in the energy range from 1 to 4.5 GeV/u at the luminosity level of 1*10²⁷ cm^-2*s⁻¹. One of the elements in the collider injection chain is BUSTER – a cycling accelerator of ions 197Au³²⁺. The injection energy of particles is 6.2 MeV/u, extraction energy is 600 MeV/u. Two RF stations are to provide 10 kV of acceleration voltage. Frequency range of operation of the stations in the injector chain is from 634 kHz to 2400 kHz. The provisions are made for autonomous mode of operation of the stations in the frequency range of 0.5 – 5.5 MHz at the same accelerating voltage. Amorphous metal rings of Russian production are used in the RF cavities. RF stations are created in the Budker Institute of Nuclear Physics, SB RAS, Novosibirsk. The stations are tested in the operative mode and will be delivered to the customer in October, 2014. Main design features and parameters of RF cavity, power generator and control system of the stations are described in the paper.

Slides TUCB02 [1.265 MB]

TUPSA09

Beam Dynamics Calculations in the Multi-Beam Generator Cavity

electron, controls, impedance, klystron

54

E.A. Savin, S.V. Matsievskiy, N.P. Sobenin
MEPhI, Moscow, Russia
A.A. Zavadtsev
Nano, Moscow, Russia

In the previously designed, calculated and tuned structure of the compact generator-cavity the beam dynamics for the different geometry options has been calculated. The influence of injected beam parameters to the output power value has been overviewed. Also the geometry of the beam tubes and couple coefficient between cavity and the output waveguide has been optimized to reach the maximum output power value.

TUPSA18

Complex Shunt Impedance and Beam-RF Cavity Interaction

impedance, damping, experiment, resonance

77

V.G. Kurakin
LPI, Moscow, Russia

Two approaches usually are used to describe beam-cavity interaction in accelerator based applications. The first one is electro dynamical and uses Maxwell equations to derive appropriate equations, field modes expressions being necessary to calculate field amplitudes excited by moving charges in the cavity. The other one uses LC circuit to derive appropriate equations for voltage amplitude induced in cavity by accelerated bunches, thin accelerating gap to some extent being not fully correctly defined representation in such approach. In this paper, the expressions are derived that describe beam-RF cavity interactions in terms of so called complex shunt impedance, strict electro dynamical approach being used in calculations. It is shown that complex shunt impedance module coincides completely with usual shunt impedance definition that up to now is used widely to describe rf cavity efficiency. The physical sense of its phase is given in the paper as well. Both complex shunt impedance module and its phase can be calculated or measured experimentally.

TUPSA20

Output Energy Variation in the SC Linac for the Proton Radiotherapy

simulation, linac, proton, focusing

80

I.A. Ashanin, S.M. Polozov, A.V. Samoshin
MEPhI, Moscow, Russia

Current success of the superconducting linear accelerators based on independently phased SC cavities gives a seriously reason to consider such structure in proton radiotherapy. Superconductivity allow to solve at once some problems concerned with a low rate of energy gain, high length, higher capacity losses and higher cost of the proton linear accelerator subsequently. One of the traditional aims of such facilities is receiving of the beam energy about 240 MeV with possibility of fluently regulation in range from 150 to 240 MeV that responds to irradiate the tumors located at different depth. The possibility of beam energy variation by means of RF field phase in last resonators and number of the resonator turn-off becomes the major advantage of the proton SC linac. The optimal choice of accelerator parameters and the beam dynamics simulation results with using BEAMDULAC-SCL code will presented*. Methods of the output energy variation with beam quality preservation in the proton SC linac will discussed.
* A.V. Samoshin. Proc. of LINAC2012, Tel-Aviv, Israel, TUPB069, p. 630 - 632

TUPSA26

Electrodes Form Optimization of RF Deflecting System Wobbler for FAIR Project

heavy-ion, ion, target, experiment

91

A. Sitnikov, A. Golubev, T. Kulevoy, S.A. Visotski
ITEP, Moscow, Russia

Funding: SAEC "Rosatom" and Helmholtz Association
The new method for high energy density states in matter investigation, which based on irradiation of combined target by hollow high energy heavy ion beam was proposed in the Institute for theoretical and experimental physics (ITEP). The target consists of a sample of matter at the center and a hollow shell around it. The experiment of high energy density states generation will be carry on at FAIR project. The RF deflecting system (Wobbler) for hollow high energy heavy ion U²⁸⁺ beam with kinetic energy Wk=1 GeV/n formation is developing at ITEP. The current results of electrodes form optimization for RF deflecting system (Wobbler) which is developing at ITEP for FAIR project are shown in this paper.

WEPSB04

Field Optimization Technique of the Multigap H-mode Resonators

impedance, linac, acceleration

162

S.E. Toporkov, A.B. Buleiko, M.V. Lalayan
MEPhI, Moscow, Russia

Optimization of the H-mode resonators requires uniform accelerating field distribution on its axes. To realize this task pylons with the holes on its end walls are used in many cases. During applying this technique in case of cavities with low number of periods it was mentioned that the best value of the field flatness was obtained in case of zero gap between end walls of the resonator and the pylon. It means that each pylon has got the electrical contact with one of the end walls of the resonator. For such cavity geometry magnetic field distribution differs from the classical H – resonator: it transforms in one common magnetic flux like in split-coaxial cavities. The analysis of such structures was performed for two types of H-mode resonators: Cross bar H-mode (CH) resonators with working frequency 324MHz and Interdigital H-mode (IH) resonators with working frequency 162MHz. All types of resonators work on the pi-mode and have 9 accelerating gaps. The main stages of E-field flatness optimization inside CH⁻ and IH⁻ cavities are presented at this paper.

WEPSB05

Optimization of Electric Field Distribution Inside Multi-gap CH-Resonator

impedance, proton, acceleration, rfq

164

S.E. Toporkov
MEPhI, Moscow, Russia

This paper presents the results of the electrodynamic modelling of the Crossbar H-mode (CH) resonator. The main goal was to get the uniform accelerating field distribution and to optimize effective shunt impedance. The initial model of the 324 MHz cavity consists of 7 equidistant RF gaps with the period length 46.26 mm. To optimize its electrodynamic characteristics the design contains pylons. Solution of the tuning task consists of several steps. Firstly it was chosen the optimal relation between the holding rod length and the pylon's height. Then the most significant improvement on the E-field distribution was introduced by optimizing the gap between end walls of the resonator and the pylon. The final adjustment of the field distribution and the tuning to the working frequency was performed by means of the holes in the pylon. Correct geometry increases effective shunt impedance from 55 MOhm/m to 80 MOhm/m and improves the field flatness to the 97%. The results of optimization the cavities for different particle velocities with 7,9 and 11 accelerating gaps and different aperture diameter are presented.

WEPSB06

The Optimization of the Buncher at 145.2 MHz to Reduce Multipactor Effect

simulation, electron, injection, beam-transport

166

M. Gusarova, T. Kulevoy, I.I. Petrushina, A.S. Plastun, S.M. Polozov
MEPhI, Moscow, Russia
T. Kulevoy, A.S. Plastun
ITEP, Moscow, Russia

The results of the optimization of the cavity of the single gap buncher at 145.2 MHz to reduce multipacting effect are presented. Resonant voltages, impact energies and corresponding particle trajectories are obtained. The variants of design to reduce multipacting effect are considered.

WEPSB08

Multi-beam Generator Cavity for the Proton Linear Accelerator Feeding System on 991 MHz Frequency Geometry Optimization

coupling, impedance, proton, electron

171

E.A. Savin, S.V. Matsievskiy, N.P. Sobenin
MEPhI, Moscow, Russia
A.A. Zavadtsev
Nano, Moscow, Russia

For the proton linear accelerator feeding system 800 kW input power value is required. The system consists from pillbox cavity with six beam tubes connected to the rectangular waveguide as a power output system is designed. In case of using high voltage gun with modulated six-bunch injection, this system allows to transform the energy of electron bunches which flies throw beam tubes to accelerating section feeding power. Different types of the structure geometry were calculated. The whole structure consists both from generator cavity and accelerating structure has been designed.

WEPSB12

Cascade Interference Switches for Active Microwave Compressors

operation, extraction, experiment, distributed

180

S.A. Gorev, S.N. Artemenko, V.A. Avgustinovich, V.S. Igumnov, V.L. Kaminski, S.A. Novikov, Yu.G. Yushkov
TPU, Tomsk, Russia

Funding: "Science" state order of the Russian Ministry of Education and Science.
Results of study energy extraction devices for S-band microwave pulse compressors are presented. The devices are manufactured as interference switches produced from the circular single mode waveguide and that are differs only by the cascade of identical H-plane T-junctions connected in series at a side arm of H-tee. The versions cascade switches which are matched and unmatched from the side of auxiliary arm of T-junction are investigated. It is shown the variant of cascade switches with the matched T-junctions allows decrease the switching power level few times comparatively the switching power of usual one. Possibility of increasing operation power and stability of output pulses of microwave pulse compressors with such energy extraction devices are confirmed in experiments. There are presented the results of investigation the cascade including two and three switches connected in series by straight arms. It is shown the switching power level for such type cascade switches can be many less than for usual switch with one T-junction. Results of experimental study cascade switches of such type confirming with the results of the theoretical analyses are presented and peculiarities of cascade switches are mentioned. The assumption about good perspectives for the cascade switches manufactured from oversized rectangular waveguide is formulated. The obtained results concerning of the cascade switch operation have been demonstrated the possibility of increasing switch operation power.

WEPSB13

Oversized Interference Switches of Active Microwave Pulse Compressors

extraction, coupling, operation, plasma

183

V.S. Igumnov, S.N. Artemenko, V.A. Avgustinovich, S.A. Gorev, V.L. Kaminski, S.A. Novikov, Yu.G. Yushkov
TPU, Tomsk, Russia

Funding: "Science" state order of the Russian Ministry of Education and Science.
Results of simulation and experimental study of two types of the oversized interference switches are presented. The switch of the first type was developed on basis of the simulation of the oversized rectangular waveguide H-tee with the H01 operation mode. Conditions of effective operation of the first type switch as an energy extraction element of active microwave pulse compressors are determined. The output pulse power of 2.8 MW and pulse width of 3.5 ns with the corresponding amplification factor of 17.5 dB for were obtained in the X-band microwave pulse compressor prototype containing the storage cavity made of WR-284 waveguide and the switch made of the waveguide with the cross section area of 58×25 mm2. The results of experimental study of the oversized X-band interference switch of the second type with the synchronous energy extraction through a compact packet of common single mode switches incorporating the five identical waveguide tees are presented as well. Possibility of full synchronization of the switch packet is proved and the conditions of such synchronization are determined. Permissible quantity of the switches in a packet unit is estimated. The output pulse power of 0.8 MW, pulse width of 3.2 ns at the power gain of 12 dB and the pulse power of 2.2 MW, pulse width of 3.5 ns at the power gain of 16.5 dB were obtained when the energy extraction from the five different single mode resonant cavities and an oversized cavity respectively was synchronous.

THX02

Experience in Research, Development, Construction and Commissioning of Normally Conducting Accelerating Structures

linac, coupling, HOM, simulation

278

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

The experience and results of research, development, construction and start of normally conducting accelerating structures for high intensity hadron linear accelerators at medium and high energii is summarized Created methods and obtained results provided construction and start of operation of accelerating system in INR H⁻ linac with designed energy 600 MeV. The research results allow generalize the properties of high energy structures and develop methods and criteria for improvements, with were realized in the development and commissioning of accelerating structures in another foreign laboratories. Basing on research results, the high energy accelerating structure, which surpasses analogues in the total list of parameters, is proposed and approved.

Slides THX02 [1.259 MB]

THCE02

CW 100 keV Electron RF Injector for 40 mA Average Beam Current

cathode, gun, electron, vacuum

309

V. Volkov, V.S. Arbuzov, K.N. Chernov, E.I. Kolobanov, S.A. Krutikhin, E.A. Kuper, I.V. Kuptsov, G.Y. Kurkin, S.V. Motygin, V.N. Osipov, V.K. Ovchar, V.M. Petrov, V.V. Repkov, M.A. Scheglov, I.K. Sedlyarov, G.V. Serdobintsev, S.S. Serednyakov, S.V. Tararyshkin, A.G. Tribendis
BINP SB RAS, Novosibirsk, Russia
I.V. Shorikov
RFNC – VNIIEF, Sarov, Russia
A.V. Telnov, N.V. Zavyalov
VNIIEF, Sarov, Russia

CW 100 keV electron RF gun for 40 mA average beam current was developed, built and commissioned at BINP SB RAS. The RF gun consists of normal conducting 100 MHz RF cavity with a gridded thermo cathode unit, CW 16 kW generator with GU-92A tetrode in the output stage and a set of LLRF electronics. The gun was tested up to the design specifications at a test bench that includes a diagnostics beam line. The design features of different components of the gun are presented. Preparation and commissioning experience is discussed. The beam test results are summarized.

THPSC03

Study of Superconducting Accelerating Structures for Megawatt Proton Driver Linac

linac, simulation, accelerating-gradient, proton

318

S.M. Polozov, K.A. Aliev, A.M. Fadeev, M. Gusarova, T. Kulevoy, M.V. Lalayan, N.P. Sobenin, O. Verjbitskiy
MEPhI, Moscow, Russia

Funding: This project was supported by the Ministry of Science and Education of Russia under contract No. 14.516.11.0084
The preliminary design of megawatt level proton accelerator-driver is carrying out by collaboration between Russian scientific centers MEPhI, ITEP, Kurchatov Institute. This project was supported in 2013 by the Ministry of Science and Education of Russia. The linac general layout includes SC Spoke-cavities at middle energy range and elliptical cavity at high energy one. The usage of QWR and/or HWR at 10-30 MeV was also discussed. Due to electrodynamics models of all structures types were designed and the electrodynamics characteristics were studied. QWR, HWQ and Spoke-cavities were proposed to operate on 324 MHz and elliptical cavities on 972 MHz. The main electrodynamics simulation results will present in report. The multipactor study results will also discussed.

THPSC04

Study of Normal Conducting Accelerating Structures for Megawatt Proton Driver Linac

rfq, linac, Windows, coupling

321

S.M. Polozov, A.E. Aksentyev, A.A. Kalashnikova, T. Kulevoy, M.V. Lalayan, S.E. Toporkov
MEPhI, Moscow, Russia

Funding: This project was supported by the Ministry of Science and Education of Russia under contract No. 14.516.11.0084
The preliminary design of megawatt level proton accelerator-driver is carrying out by collaboration between Russian scientific centers MEPhI, ITEP, Kurchatov Institute. This project was supported in 2013 by the Ministry of Science and Education of Russia. The linac general layout includes RFQ section and section(s) with radiofrequency focusing. The different types of RF focusing were studied due to this project: RF crossed lenses, modified electrodes RFQ, axi-symmetrical RF focusing. All such focusing can be realized by IH-type cavities. The design of segmented vane RFQ (SVRFQ) with coupling windows and IH⁻ and CH-type normal conducting cavities will discuss in the report. All cavities operate on 162 MHz. The main electrodynamics simulation results will present.

THPSC16

Analysis of High Order Modes Damping Techniques for 800 MHz Single Cell Superconducting Cavities

HOM, damping, dipole, luminosity

353

Ya.V. Shashkov, N.P. Sobenin
MEPhI, Moscow, Russia
M. Zobov
INFN/LNF, Frascati (Roma), Italy

Funding: Research supported by RFBR grant 13-02-00562/14 and EU FP7 HiLumi LHC - Grant Agreement 284404
The High Luminosity LHC upgrade program foresees a possibility of using the second harmonic cavities working at 800 MHz for the collider bunch length variation. Such harmonic cavities should provide an opportunity to vary the length of colliding bunches. In order to supply the required harmonic voltage several single cell superconducting cavities are to be used. Different cavity designs and several higher order mode (HOM) damping techniques are being studied in order to reduce the cavity HOM impact on the beam stability and to minimize parasitic power losses. In this paper we analyze and compare the HOM electromagnetic characteristics and respective wake potential decay rates for cavities with grooves, fluted and ridged beam pipes. The problem of Lorentz force detuning is also addressed.

THPSC17

Higher Order Modes Damping for 9-cell Structure with Modified Drift Tubes

HOM, damping, quadrupole, dipole

356

Ya.V. Shashkov, A.A. Mitrofanov, N.P. Sobenin
MEPhI, Moscow, Russia
V. Zvyagintsev
TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada

Funding: Research supported by RFBR grant 13-02-00562/14
This paper is focused on HOM damping in 9-cell superconducting cavities. We are considering HOM propagation outside from the cavity ridged and fluted drift tubes. The analysis of the influence of the parameters of the drift tube on the HOM damping was conducted. The considered methods were analysed and compared.

THPSC18

Suppression of Mechanical Oscillations in Quarterwave 10⁶ MHz Resonator

simulation, niobium, TRIUMF, superconductivity

359

M. Gusarova, I.I. Petrushina, I.V. Rybakov, Ya.V. Shashkov, Ya.V. Shashkov, V. Zvyagintsev
MEPhI, Moscow, Russia
V. Zvyagintsev
TRIUMF, Canada's National Laboratory for Particle and Nuclear Physics, Vancouver, Canada

Analytical calculations and numerical simulations have been done for mechanical eigenmodes of quarter wave superconducting resonators with operating frequency of 10⁶ MHz and 80 MHz. A possibility of frequency shift of mechanical modes in 106 MHz resonator has been estimated by application of the damper. We have optimized the damper's position for suppression efficiency. We have also compared the numerical and experimental results.

THPSC19

Influence of the Different Geometric Parameters of Superconducting Elliptical Cavities on the Multipactor

accelerating-gradient, electron, simulation, multipactoring

362

M. Gusarova, I.I. Petrushina
MEPhI, Moscow, Russia

The results of numerical simulations of multipacting in the different superconducting elliptical cavities are presented. Question of influence of the aperture radius, equator shape, iris shape and frequency and electron trajectories for different geometrical parameters of elliptic structures are considered.

THPSC20

Multipactor in Elliptical Cavities 800 MHz

electron, damping, HOM, resonance

365

M. Gusarova, I.I. Petrushina
MEPhI, Moscow, Russia

The studies of the multipacting discharge possibility in elliptic single-cell cavities at 800 MHz with three types of hifger order modes couplers were done. The ranges of the field gradients where the conditions for the occurrence of first order multipacting discharge in the equatorial region, as well as the HOM field levels were determined.

THPSC33

Digital Signal Processing Algorithms for Linac Low-Level RF Systems

FPGA, controls, operation, embedded

392

D.A. Liakin, S.V. Barabin, A.Y. Orlov
ITEP, Moscow, Russia

A set of LLRF systems had been designed for various applications of resonant RF devices such as accelerators or beam deflectors. This report presents compact signal detection algorithms, used in most of developed systems. Application-specific extension of the signal processing procedure allows the system be synchronized to external self-excited oscillator.

Poster THPSC33 [13.540 MB]

THPSC50

Neutron Accelerating Tubes with Microwave Deuterons Source Using Electron-cyclotron Resonance Effect

neutron, ion, plasma, ECR

441

A.N. Didenko, B.Y. Bogdanovich, K.I. Kozlovskiy, A. Nesterovich, A.V. Prokopenko, V.L. Shatokhin, A.E. Shikanov
MEPhI, Moscow, Russia

The physical principles of increased efficiency neutron accelerating tubes based on the microwave sources of heavy hydrogen nuclides, using the electron-cyclotron resonance effect (ECR) are considered. The authors' theoretical results are given on electromagnetic oscillations generation in the working volume of the ion source of the accelerating tube with the boundary excitation of a microwave discharge. Resonator and waveguide modes for ECR-plasma excitation are thus examined. Features of neutron generation in these accelerator neutron tubes based on microwave source of heavy hydrogen nuclides are analyzed. The algorithm is developed and numerical simulation of neutron pulse formation in neutron generators based on microwave source is done taking into account target shape and the possible deuterons resonant recharge. Frequency dependences of the energy flux density transmitted from an alternating electromagnetic field to the electron component of the plasma are obtained depending on the constant longitudinal magnetic field induction and pressure in the discharge chamber. The results of these studies could form the basis for the efficient domestic portable neutron generators development based on accelerating tubes with microwave hydrogen nuclides sources.