RuPAC2014 - Classification: 12 Ion sources and electron guns

Paper

Title

Page

INR RAS Linac Proton Injector 100 Hz PRR Operation Mode

306

A. Belov, O.T. Frolov, L.P. Nechaeva, E.S. Nikulin, A.V. Turbabin, V. Zubets
RAS/INR, Moscow, Russia

The injector provides INR RAS linac by proton beam with energy 400 keV, 200 mks pulse duration at pulse repetition rate 50 Hz. PRR of the proton injector has been increased to 100 Hz with goal of rising the accelerator average beam current. Main stages and results of the injector modernization are presented.

Slides THCE01 [3.518 MB]

THCE02

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

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.

THPSC46

Simulation and Optimization of Ion Optical Extraction, Acceleration and H-minus Ion Beam Matching Systems

429

B.A. Frolov
IHEP, Moscow Region, Russia
V.S. Klenov, V.N. Mikhailov, O. Volodkevich
RAS/INR, Moscow, Russia

Source of negative hydrogen ions for the implementation of multiturn charge-exchange injection to increase the intensity of IHEP buster is developed. Surface-plasma ion source with Penning discharge is selected as a source of H-minus ions. A high-current extraction system with downstream electron dumping has been designed. A three-dimensional ion optical code IBSimu has been utilized for modelling and optimization the extraction system and ion beam acceleration to energy of 100 keV. A magnetic low energy beam transport line consisting of two solenoids has been designed to match the beam with RFQ. TRACE 2D code was used to optimize LEBT. A deflecting magnet with small angular deflection (10) has been installed between solenoids to eliminate forward tracing of neutral atoms from ions source to RFQ.

THPSC47

Production of Metal Ion Beams from ECR Ion Sources by MIVOC Method

432

K.I. Kuzmenkov, S.L. Bogomolov, A.E. Bondarchenko, A.A. Efremov, N. Lebedev, K.V. Lebedev, V.Ya. Lebedev, V.N. Loginov, Yu. Yazvitsky
JINR, Dubna, Moscow Region, Russia
Z. Asfari, B.J.P. Gall
IPHC, Strasbourg Cedex 2, France

Funding: Work supported by Russian Foundation for Basic Research under grant number 13-02-12011
The production of metal ion beams with ECR ion sources using MIVOC method is described. The method is based on the use of metal compounds having a high vapor pressure at room temperature: for example, C2B10H12, Fe(C5H5)2 and several others. Intense ion beams of B and Fe were produced at the FLNR JINR cyclotrons using this method. The main efforts were went into production and acceleration of 50Ti ion beam at the U-400 cyclotron. The experiments on production of 50Ti ion beam were performed at the test bench with the natural and enriched compounds of titanium (CH3)5C5Ti(CH3)3. In the experiments at the test bench the beam currents of Ti⁵⁺ - 80 mkA and Ti¹¹⁺ - 70 mkA were achieved at different settings of the source. After successful tests two 3 weeks runs with Ti-50 beam were performed at the U-400 cyclotron for the experiments on spectroscopy of super heavy elements. The intensity of the injected beam of 50Ti⁵⁺ was about of 50-60 mkA, during experiment the source have shown stable operation. The compound consumption rate was determined to be about of 2.4 mg/h, corresponding to 50Ti consumption of 0.52 mg/h.

THPSC48

Hydrogen Nuclides Acceleration from Laser Plasma in the Diode with Magnetic Insulation of Electrons

435

A.E. Shikanov, K.I. Kozlovskiy, V.L. Shatokhin, E.D. Vovchenko
MEPhI, Moscow, Russia

New experimental results of obtaining accelerated deuterons in the small-sized diode with magnetic insulation are reported. The effective mode of ion acceleration to energies at 300 keV in the diode with a high voltage anode in order to initiate nuclear reactions D(d, n)3He is obtained with diode current ~0,5 kA and impulse duration ~1 mks in vacuum ~5*10^-2 Pa. Containing deuterons laser plasma was generated at the anode during TiD target laser irradiation with a wavelength of 1.06 microns and a power density of ~5*10¹⁴ W/m2. Accelerating voltage impulse was formed using Arkadyev–Marx 20 cascade impulse voltage generator with air insulation. Diode cathode covers the anode symmetrically. It is a hollow cylinder permanent magnet with induction on the axis ~0,4 T. Magnetic insulation in accelerating gap leads to suppression of the accelerated electrons current at level of 0.5 in relation to the total diode current. Used methods of accelerating diode ion current, accelerating impulse voltage and penetrating radiations characteristics measurements are described.

THPSC49

Hydrogen Nuclides Removing From Pulse Plasma Formations

438

B.Y. Bogdanovich, A. Nesterovich, V.L. Shatokhin, A.E. Shikanov
MEPhI, Moscow, Russia

The features of hydrogen nuclides extraction from vacuum-arc plasma and laser sources by electric field research results are presented in the report. Such sources can be used in accelerators injection systems and in neutron generators. These processes, found, are strongly influenced by electrostatic oscillations in the plasma boundary, which position continuously varies, in addition to the ions thermal motion. Such movement kinematics determined by the velocity field in plasma formation and its concentration reducing because of the ions extraction. On the basis of this model it shows that plasma boundary moves initially in the direction to the ejection electrode, then stops and begins quickly move back. An equation for the nuclides emission current density from hydrogen plasma surface for their quasiplanar extraction geometry is obtained.

THPSC50

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

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.

THPSC51

Ion Source Deuteron Beam Acceleration in Gas-filled Ion-optic System

444

V.I. Rashchikov
MEPhI, Moscow, Russia

Deuteron beam acceleration in ion-optic system of gas-filled neutron tubes was investigated. PIC code SUMA* used for computer simulation of ionization and knock on processes and there influence on deuteron beam parameters. When deuteron and ionized particles space charge self-field forces become the same order of magnitude as external one, virtual cathode may occurs. It is happens because of injected from ion source deuterons cannot overcome their own space charge potential wall and move in transverse direction. However, electrons, produced by ionization, are trapped within the deuteron beam space charge potential wall and decrease it significantly. Thus, space charge neutralization of deuteron beams by electrons, may considerably increase target current and, as a result, output neutron flow. Moreover, own longitudinal electric field rise near the target leads to reduction of accelerating electrode – target potential wall, which was made to prevent knock on emission from the target. As a result, additional knocked on electrons may appear in the region and should be taken into account. The data obtained were compared with experimental results.
* A.N. Didenko, V.I. Rashchikov, V.E. Fortov, Technical Physics, Vol. 56, No. 10,pp. 1535–1538, 2011

THPSC52

Dynamics of Plasma-Beam Formations in the Acceleration Gap of the Pulse Neutron Generator-based Vacuum Neutron Tube

447

S. Sergey, S. Maslennikov, E. Shkolnikov
National Research Nuclear University (MEPhI), Moscow, Russia
A. Agafonov
LPI RAS, Moscow, Russia

The analysis of dynamics of plasma flows containing deuterium, zirconium ions, and electrons in acceleration gap of the pulsed neutron generator vacuum neutron tube* is presented in the paper. The investigations have been undertaken with the use of code KARAT** for the two-dimensional time-dependant regime. The limiting currents of each component for the real geometry of acceleration gap have been determined. The differences between the values of these currents and those determined with the use of the Child-Langmuir equation have been demonstrated. The analysis of dynamics of plasma emitter in the gap has been performed by the example of accelerating voltage of 120 kV and pulse duration of 1.2 mks. It has been shown that the value of the current incoming in the gap from the ions source can differ strongly from the current value at the target. For increasing of this value the partitioning of acceleration gap with the use of conductive grid which is transparent for beam and has several geometric configurations has been proposed. The ring configuration of the emitter has been considered for the same purposes. The calculations have shown that the combination of these two methods described above can allow transporting deuterons current from the anode grid to the target without losses.
* E.P.Bogolubov, V.I.Ryzhkov, D.I.Yurkov. Conference "PNG and Technologies on Their Basis",2013,p.14.
** V.P.Tarakanov. User's Manual for Code KARAT. Berkeley Research Associates, Inc. 1992, p.127.

THPSC53

The NG-10 Neutron Generator for Production of Neutron Fluxes in Continuous and Pulse Modes

450

D.A. Solnyshkov, A.V. Antonov, A.N. Kuzhlev, N.P. Mikulinas, A.V. Morozov, G.G. Voronin
NIIEFA, St. Petersburg, Russia

Designed neutron generator is designed for a neutron yield 1x10¹¹ neutrons / s in continuous mode and includes ion accelerator with an accelerating voltage, continuously adjustable in the range of 120-150 keV and a beam current of atomic deuterium ions up to 2 mA, and the target device, in which used Ti-T target different diameters. In addition to high and stable yield of neutrons in time when operating continuously generator provides pulsed mode of operation over a wide range of duration and pulse repetition rate. Pulsed neutron generator operation is performed by modulating the discharge current of the ion source. For this purpose, a unique system of power discharge, which allows for both continuous and pulse modes. In this case it is possible to produce a smooth adjustment of the pulse width of the beam current. Switch from pulse mode to DC promptly made with the remote control.

THPSC54

Studies on Radially-Directed Electron Beam Formation in the Secondary-Emission Source

N.G. Reshetnyak, N. Ayzatsky, I.A. Chertishchev, A.N. Dovbnya, A.S. Mazmanishvili, V.P. Romas'ko
NSC/KIPT, Kharkov, Ukraine

The present paper describes the experimental and theoretical data on radial electron beam formation in a secondary-emission source during the beam transport in a decreasing magnetic field of the solenoid. The magnetron gun with a secondary-emission cathode, 36 mm in diameter, and a 78 mm anode, was used as an electron source. The beam transport was performed in the system for two cases. In the first case, the system consisted of 5 rings with an inside diameter 66 mm and of width 30 mm; and in the second case, the system included 15 copper rings of inside diameter 66 mm and 8 mm wide, and was at a distance of 85 mm from the anode of the magnetron gun. In the second case, for realization of the local decrease of the solenoidal field a scattered magnetic field was used, the magnetic field being produced by a SmCO5 permanent magnet. The beam current and its distribution along the length of ring system were investigated as functions of the magnetic field amplitude and the gradient of field decrease in the electron energy range from 35 till 85 keV. The mode of electron current bunch formation was also studied. A mathematical model of electron flow motion in the decreasing field has been constructed. Numerical results are found to be in satisfactory agreement with the experimental data.

FRCA02

Time Dependence of Ion Beam Transverse Phase-Space Portrait Orientation During Linac Proton Injector Pulse

459

O.T. Frolov, A. Belov, S.E. Golubovskiy, E.S. Nikulin, V. Zubets
RAS/INR, Moscow, Russia

As a result of analysis conducted a transients of the 400 kV column intermediate electrode potential have been determined as one of the main processes responsible for change of beam phase-space portrait orientation during 200 mks, 50 Hz proton injector high voltage accelerating pulse. Beam transport simulation shows high sensitivity of the beam phase-space portrait orientation to variation of the intermediate electrode potential. It has been found that significant variation of this potential takes place due to transition process during a pulse in the capacitor-resistor voltage water divider of the accelerating tube. The divider capacities matching procedure has been performed. The beam emittance measurements results have shown that within the accuracy of observation the beam transverse phase-space portrait orientation remains constant during injector pulse with the accelerating tube voltage divider being compensated.

Slides FRCA02 [0.824 MB]

Paper	Title	Page
THCE01	INR RAS Linac Proton Injector 100 Hz PRR Operation Mode	306
	A. Belov, O.T. Frolov, L.P. Nechaeva, E.S. Nikulin, A.V. Turbabin, V. Zubets RAS/INR, Moscow, Russia
	The injector provides INR RAS linac by proton beam with energy 400 keV, 200 mks pulse duration at pulse repetition rate 50 Hz. PRR of the proton injector has been increased to 100 Hz with goal of rising the accelerator average beam current. Main stages and results of the injector modernization are presented.
	Slides THCE01 [3.518 MB]

THCE02	CW 100 keV Electron RF Injector for 40 mA Average Beam Current	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.

THPSC46	Simulation and Optimization of Ion Optical Extraction, Acceleration and H-minus Ion Beam Matching Systems	429
	B.A. Frolov IHEP, Moscow Region, Russia V.S. Klenov, V.N. Mikhailov, O. Volodkevich RAS/INR, Moscow, Russia
	Source of negative hydrogen ions for the implementation of multiturn charge-exchange injection to increase the intensity of IHEP buster is developed. Surface-plasma ion source with Penning discharge is selected as a source of H-minus ions. A high-current extraction system with downstream electron dumping has been designed. A three-dimensional ion optical code IBSimu has been utilized for modelling and optimization the extraction system and ion beam acceleration to energy of 100 keV. A magnetic low energy beam transport line consisting of two solenoids has been designed to match the beam with RFQ. TRACE 2D code was used to optimize LEBT. A deflecting magnet with small angular deflection (10) has been installed between solenoids to eliminate forward tracing of neutral atoms from ions source to RFQ.

THPSC47	Production of Metal Ion Beams from ECR Ion Sources by MIVOC Method	432
	K.I. Kuzmenkov, S.L. Bogomolov, A.E. Bondarchenko, A.A. Efremov, N. Lebedev, K.V. Lebedev, V.Ya. Lebedev, V.N. Loginov, Yu. Yazvitsky JINR, Dubna, Moscow Region, Russia Z. Asfari, B.J.P. Gall IPHC, Strasbourg Cedex 2, France
	Funding: Work supported by Russian Foundation for Basic Research under grant number 13-02-12011 The production of metal ion beams with ECR ion sources using MIVOC method is described. The method is based on the use of metal compounds having a high vapor pressure at room temperature: for example, C2B10H12, Fe(C5H5)2 and several others. Intense ion beams of B and Fe were produced at the FLNR JINR cyclotrons using this method. The main efforts were went into production and acceleration of 50Ti ion beam at the U-400 cyclotron. The experiments on production of 50Ti ion beam were performed at the test bench with the natural and enriched compounds of titanium (CH3)5C5Ti(CH3)3. In the experiments at the test bench the beam currents of Ti⁵⁺ - 80 mkA and Ti¹¹⁺ - 70 mkA were achieved at different settings of the source. After successful tests two 3 weeks runs with Ti-50 beam were performed at the U-400 cyclotron for the experiments on spectroscopy of super heavy elements. The intensity of the injected beam of 50Ti⁵⁺ was about of 50-60 mkA, during experiment the source have shown stable operation. The compound consumption rate was determined to be about of 2.4 mg/h, corresponding to 50Ti consumption of 0.52 mg/h.

THPSC48	Hydrogen Nuclides Acceleration from Laser Plasma in the Diode with Magnetic Insulation of Electrons	435
	A.E. Shikanov, K.I. Kozlovskiy, V.L. Shatokhin, E.D. Vovchenko MEPhI, Moscow, Russia
	New experimental results of obtaining accelerated deuterons in the small-sized diode with magnetic insulation are reported. The effective mode of ion acceleration to energies at 300 keV in the diode with a high voltage anode in order to initiate nuclear reactions D(d, n)3He is obtained with diode current ~0,5 kA and impulse duration ~1 mks in vacuum ~510^-2 Pa. Containing deuterons laser plasma was generated at the anode during TiD target laser irradiation with a wavelength of 1.06 microns and a power density of ~510¹⁴ W/m2. Accelerating voltage impulse was formed using Arkadyev–Marx 20 cascade impulse voltage generator with air insulation. Diode cathode covers the anode symmetrically. It is a hollow cylinder permanent magnet with induction on the axis ~0,4 T. Magnetic insulation in accelerating gap leads to suppression of the accelerated electrons current at level of 0.5 in relation to the total diode current. Used methods of accelerating diode ion current, accelerating impulse voltage and penetrating radiations characteristics measurements are described.

THPSC49	Hydrogen Nuclides Removing From Pulse Plasma Formations	438
	B.Y. Bogdanovich, A. Nesterovich, V.L. Shatokhin, A.E. Shikanov MEPhI, Moscow, Russia
	The features of hydrogen nuclides extraction from vacuum-arc plasma and laser sources by electric field research results are presented in the report. Such sources can be used in accelerators injection systems and in neutron generators. These processes, found, are strongly influenced by electrostatic oscillations in the plasma boundary, which position continuously varies, in addition to the ions thermal motion. Such movement kinematics determined by the velocity field in plasma formation and its concentration reducing because of the ions extraction. On the basis of this model it shows that plasma boundary moves initially in the direction to the ejection electrode, then stops and begins quickly move back. An equation for the nuclides emission current density from hydrogen plasma surface for their quasiplanar extraction geometry is obtained.

THPSC50	Neutron Accelerating Tubes with Microwave Deuterons Source Using Electron-cyclotron Resonance Effect	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.

THPSC51	Ion Source Deuteron Beam Acceleration in Gas-filled Ion-optic System	444
	V.I. Rashchikov MEPhI, Moscow, Russia
	Deuteron beam acceleration in ion-optic system of gas-filled neutron tubes was investigated. PIC code SUMA* used for computer simulation of ionization and knock on processes and there influence on deuteron beam parameters. When deuteron and ionized particles space charge self-field forces become the same order of magnitude as external one, virtual cathode may occurs. It is happens because of injected from ion source deuterons cannot overcome their own space charge potential wall and move in transverse direction. However, electrons, produced by ionization, are trapped within the deuteron beam space charge potential wall and decrease it significantly. Thus, space charge neutralization of deuteron beams by electrons, may considerably increase target current and, as a result, output neutron flow. Moreover, own longitudinal electric field rise near the target leads to reduction of accelerating electrode – target potential wall, which was made to prevent knock on emission from the target. As a result, additional knocked on electrons may appear in the region and should be taken into account. The data obtained were compared with experimental results. * A.N. Didenko, V.I. Rashchikov, V.E. Fortov, Technical Physics, Vol. 56, No. 10,pp. 1535–1538, 2011

THPSC52	Dynamics of Plasma-Beam Formations in the Acceleration Gap of the Pulse Neutron Generator-based Vacuum Neutron Tube	447
	S. Sergey, S. Maslennikov, E. Shkolnikov National Research Nuclear University (MEPhI), Moscow, Russia A. Agafonov LPI RAS, Moscow, Russia
	The analysis of dynamics of plasma flows containing deuterium, zirconium ions, and electrons in acceleration gap of the pulsed neutron generator vacuum neutron tube* is presented in the paper. The investigations have been undertaken with the use of code KARAT** for the two-dimensional time-dependant regime. The limiting currents of each component for the real geometry of acceleration gap have been determined. The differences between the values of these currents and those determined with the use of the Child-Langmuir equation have been demonstrated. The analysis of dynamics of plasma emitter in the gap has been performed by the example of accelerating voltage of 120 kV and pulse duration of 1.2 mks. It has been shown that the value of the current incoming in the gap from the ions source can differ strongly from the current value at the target. For increasing of this value the partitioning of acceleration gap with the use of conductive grid which is transparent for beam and has several geometric configurations has been proposed. The ring configuration of the emitter has been considered for the same purposes. The calculations have shown that the combination of these two methods described above can allow transporting deuterons current from the anode grid to the target without losses. * E.P.Bogolubov, V.I.Ryzhkov, D.I.Yurkov. Conference "PNG and Technologies on Their Basis",2013,p.14. ** V.P.Tarakanov. User's Manual for Code KARAT. Berkeley Research Associates, Inc. 1992, p.127.

THPSC53	The NG-10 Neutron Generator for Production of Neutron Fluxes in Continuous and Pulse Modes	450
	D.A. Solnyshkov, A.V. Antonov, A.N. Kuzhlev, N.P. Mikulinas, A.V. Morozov, G.G. Voronin NIIEFA, St. Petersburg, Russia
	Designed neutron generator is designed for a neutron yield 1x10¹¹ neutrons / s in continuous mode and includes ion accelerator with an accelerating voltage, continuously adjustable in the range of 120-150 keV and a beam current of atomic deuterium ions up to 2 mA, and the target device, in which used Ti-T target different diameters. In addition to high and stable yield of neutrons in time when operating continuously generator provides pulsed mode of operation over a wide range of duration and pulse repetition rate. Pulsed neutron generator operation is performed by modulating the discharge current of the ion source. For this purpose, a unique system of power discharge, which allows for both continuous and pulse modes. In this case it is possible to produce a smooth adjustment of the pulse width of the beam current. Switch from pulse mode to DC promptly made with the remote control.

THPSC54	Studies on Radially-Directed Electron Beam Formation in the Secondary-Emission Source
	N.G. Reshetnyak, N. Ayzatsky, I.A. Chertishchev, A.N. Dovbnya, A.S. Mazmanishvili, V.P. Romas'ko NSC/KIPT, Kharkov, Ukraine
	The present paper describes the experimental and theoretical data on radial electron beam formation in a secondary-emission source during the beam transport in a decreasing magnetic field of the solenoid. The magnetron gun with a secondary-emission cathode, 36 mm in diameter, and a 78 mm anode, was used as an electron source. The beam transport was performed in the system for two cases. In the first case, the system consisted of 5 rings with an inside diameter 66 mm and of width 30 mm; and in the second case, the system included 15 copper rings of inside diameter 66 mm and 8 mm wide, and was at a distance of 85 mm from the anode of the magnetron gun. In the second case, for realization of the local decrease of the solenoidal field a scattered magnetic field was used, the magnetic field being produced by a SmCO5 permanent magnet. The beam current and its distribution along the length of ring system were investigated as functions of the magnetic field amplitude and the gradient of field decrease in the electron energy range from 35 till 85 keV. The mode of electron current bunch formation was also studied. A mathematical model of electron flow motion in the decreasing field has been constructed. Numerical results are found to be in satisfactory agreement with the experimental data.

FRCA02	Time Dependence of Ion Beam Transverse Phase-Space Portrait Orientation During Linac Proton Injector Pulse	459
	O.T. Frolov, A. Belov, S.E. Golubovskiy, E.S. Nikulin, V. Zubets RAS/INR, Moscow, Russia
	As a result of analysis conducted a transients of the 400 kV column intermediate electrode potential have been determined as one of the main processes responsible for change of beam phase-space portrait orientation during 200 mks, 50 Hz proton injector high voltage accelerating pulse. Beam transport simulation shows high sensitivity of the beam phase-space portrait orientation to variation of the intermediate electrode potential. It has been found that significant variation of this potential takes place due to transition process during a pulse in the capacitor-resistor voltage water divider of the accelerating tube. The divider capacities matching procedure has been performed. The beam emittance measurements results have shown that within the accuracy of observation the beam transverse phase-space portrait orientation remains constant during injector pulse with the accelerating tube voltage divider being compensated.
	Slides FRCA02 [0.824 MB]