RuPAC2014 - List of Keywords (impedance)

Paper	Title	Other Keywords	Page
TUPSA04	Operating Frequency and Accelerating Structure Geometry Chose for the Travelling Wave Compact Electron Linear Accelerator	coupling, electron, linac	42
	E.A. Savin, I.D. Sokolov MEPhI, Moscow, Russia
	For the compact electron linear accelerating structure based on the hybrid scheme which consists from SW biperiodic structure buncher and TW DLS with magnetic couple TW accelerating part, the best option for the operating frequency and cells geometry has been chosen. Comparative calculations for the DLS cells with magnetic couple and without it, on the different operating frequencies and with the different couple coefficient were carried out. The best option will be manufactured, measured and used in the accelerator structure.

TUPSA09	Beam Dynamics Calculations in the Multi-Beam Generator Cavity	electron, cavity, controls, 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	cavity, 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.

WEPSB04	Field Optimization Technique of the Multigap H-mode Resonators	cavity, 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	cavity, 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.

WEPSB08	Multi-beam Generator Cavity for the Proton Linear Accelerator Feeding System on 991 MHz Frequency Geometry Optimization	cavity, coupling, 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.

WEPSB09	Comparision of Higher Order Modes Damping Techniques for Array of Single Cell Cavities	HOM, damping, extraction, higher-order-mode	174
	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 LHC High Luminosity upgrade program considers an option of using additional cavities, operating at multiplies of the main RF system frequency of 400 MHz. Such harmonic cavities should provide a possibility to vary the length of colliding bunches. In order to supply the required harmonic voltage several single cell superconducting cavities are to be used. It is desirable to house more cavities in a single cryostat to reduce the number of transitions between "warm" and "cold" parts of the cryogenic system. In this paper we study electromagnetic characteristics of a chain of the single cell superconducting cavities coupled by drifts tubes. In order to reduce the influence of Higher order modes (HOM) excited in the structure on the beam stability and to minimize eventual power losses we analyze the HOM parameters and calculate the wake potential decay rates due to application of different HOM damping devices. In particular, the methods of HOM damping with rectangular waveguides connected to the drift tubes, the loads placed in the fluted and ridged drift tubes, as well as combinations of these methods are compared. Higher order modes, superconductivity, harmonic cavities

WEPSB36	A prototype of a Phased Array for Deep Thermoradiotherapy	dipole, simulation, experiment, radiation	240
	A.M. Fadeev, A.A. Blinnikov, S.M. Ivanov, S.M. Polozov MEPhI, Moscow, Russia
	It is proven that hyperthermia increases radiation and chemotherapy efficiency. In oncology, the generation of a higher temperature at a tumor-involved region of the body is called hyperthermia. The thermoradiotherapy is widely and effective uses. A phased array of eight dipoles for the hyperthermia treatment of deep-seated tumors is proposed earlier. The power and phase coherently delivered to the radiating elements can be varied, so that the electromagnetic field is increased at the tumor location and decreased in the normal tissues. The prototype of the phased array of two dipoles and the RF power scheme are presented and results of experiments are discussed. Measured and simulated temperature distributions along the line connecting two dipoles are discussed in this paper.

Paper

Title

Other Keywords

Page

Operating Frequency and Accelerating Structure Geometry Chose for the Travelling Wave Compact Electron Linear Accelerator

coupling, electron, linac

42

E.A. Savin, I.D. Sokolov
MEPhI, Moscow, Russia

For the compact electron linear accelerating structure based on the hybrid scheme which consists from SW biperiodic structure buncher and TW DLS with magnetic couple TW accelerating part, the best option for the operating frequency and cells geometry has been chosen. Comparative calculations for the DLS cells with magnetic couple and without it, on the different operating frequencies and with the different couple coefficient were carried out. The best option will be manufactured, measured and used in the accelerator structure.

TUPSA09

Beam Dynamics Calculations in the Multi-Beam Generator Cavity

electron, cavity, controls, 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

cavity, 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.

WEPSB04

Field Optimization Technique of the Multigap H-mode Resonators

cavity, 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

cavity, 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.

WEPSB08

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

cavity, coupling, 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.

WEPSB09

Comparision of Higher Order Modes Damping Techniques for Array of Single Cell Cavities

HOM, damping, extraction, higher-order-mode

174

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 LHC High Luminosity upgrade program considers an option of using additional cavities, operating at multiplies of the main RF system frequency of 400 MHz. Such harmonic cavities should provide a possibility to vary the length of colliding bunches. In order to supply the required harmonic voltage several single cell superconducting cavities are to be used. It is desirable to house more cavities in a single cryostat to reduce the number of transitions between "warm" and "cold" parts of the cryogenic system. In this paper we study electromagnetic characteristics of a chain of the single cell superconducting cavities coupled by drifts tubes. In order to reduce the influence of Higher order modes (HOM) excited in the structure on the beam stability and to minimize eventual power losses we analyze the HOM parameters and calculate the wake potential decay rates due to application of different HOM damping devices. In particular, the methods of HOM damping with rectangular waveguides connected to the drift tubes, the loads placed in the fluted and ridged drift tubes, as well as combinations of these methods are compared.
Higher order modes, superconductivity, harmonic cavities

WEPSB36

A prototype of a Phased Array for Deep Thermoradiotherapy

dipole, simulation, experiment, radiation

240

A.M. Fadeev, A.A. Blinnikov, S.M. Ivanov, S.M. Polozov
MEPhI, Moscow, Russia

It is proven that hyperthermia increases radiation and chemotherapy efficiency. In oncology, the generation of a higher temperature at a tumor-involved region of the body is called hyperthermia. The thermoradiotherapy is widely and effective uses. A phased array of eight dipoles for the hyperthermia treatment of deep-seated tumors is proposed earlier. The power and phase coherently delivered to the radiating elements can be varied, so that the electromagnetic field is increased at the tumor location and decreased in the normal tissues. The prototype of the phased array of two dipoles and the RF power scheme are presented and results of experiments are discussed. Measured and simulated temperature distributions along the line connecting two dipoles are discussed in this paper.