ECRIS-2014 - List of Authors (Koivisto, H. A.)

Paper

Title

Page

Periodic Beam Burrent Oscillations Driven By Electron Cyclotron Instabilities In ECRIS Plasmas

5

O.A. Tarvainen, T. Kalvas, H. A. Koivisto, J.P.O. Komppula, R.J. Kronholm, J.P. Laulainen
JYFL, Jyväskylä, Finland
I. Izotov, D. Mansfeld, V. Skalyga
IAP/RAS, Nizhny Novgorod, Russia
V. Toivanen
CERN, Geneva, Switzerland

Experimental observation of cyclotron instabilities in electron cyclotron resonance ion source plasma operated in cw-mode is reported. The instabilities are associated with strong microwave emission and a burst of energetic electrons escaping the plasma, and explain the periodic oscillations of the extracted beam currents. The instabilities are shown to restrict the parameter space available for the optimization of high charge state ion currents.

Slides MOOBMH01 [2.020 MB]

MOOAMH02

High Current Proton and Deuteron Beams for Accelerators and Neutron Generators

30

V. Skalyga, S. Golubev, I. Izotov, S. Razin, V. Sidorov
IAP/RAS, Nizhny Novgorod, Russia
T. Kalvas, H. A. Koivisto, O.A. Tarvainen
JYFL, Jyväskylä, Finland
A.V. Maslennikova, A. Volovecky
Nizhny Novgorod State Medical Academy, Nizhny Novgorod, Russia

This paper presents the latest results of high current proton and deuteron beam production at SMIS 37 at the Institute of Applied Physics. In this experimental setup the plasma is created by 37.5 GHz gyrotron radiation with power up to 100 kW in a simple mirror trap. High microwave power and frequency allow sustaining higher density hydrogen plasma in comparison to conventional ECRIS's or microwave sources. The low ion temperature, on the order of a few eV, is beneficial to produce proton beams with low emittance. Latest experiments with hydrogen and deuterium show possibility of beam formation with currents up to 550 mA at high voltages below 45 kV with normalized rms emittance lower than 0.2 pi*mm*mrad. Such beams have a high potential for application in future accelerator research. Also in frames of the present paper it is suggested to use such an ion source in a scheme of D-D neutron generator. Such ion source can produce deuteron ion beams with current density up to 700-800 mA/cm². Generation of the neutron flux with density at the level of 7-8*10¹⁰ s⁻¹cm^-2 could be obtained in case of TiD2 target bombardment with deuteron beam accelerated to 100 keV.

Slides MOOAMH02 [1.961 MB]

TUOMMH05

HIISI, New 18 GHz ECRIS for the JYFL Accelerator Laboratory

99

H. A. Koivisto, P. M.T. Heikkinen, T. Kalvas, K. Ranttila, O.A. Tarvainen
JYFL, Jyväskylä, Finland
I. Izotov, V. Skalyga
IAP/RAS, Nizhny Novgorod, Russia
G. Machicoane
NSCL, East Lansing, Michigan, USA
T. Thuillier
LPSC, Grenoble Cedex, France
D. Xie
LBNL, Berkeley, California, USA

At the end of 2013 the Academy of Finland granted an infrastructure funding for the JYFL Accelerator Laboratory in order to increase beam intensities for the international user community. The primary objective is to construct a new high performance ECR ion source, HIISI (Heavy Ion Ion Source Injector), for the K130 cyclotron. Using room temperature magnets the HIISI has been designed to produce about the same magnetic field configuration as the superconducting ECRIS SUSI at NSCL/MSU for 18 GHz operation. An innovative structure will be used to maximize the radial confinement and safety of the permanent magnets. The sextupole magnets are separated and insulated from the plasma chamber providing two advantages: 1) the permanent magnets can be cooled down to -20˚C, which increases especially their coercivity and 2) makes it possible to reach higher radial field at the inner surface of plasma chamber. Comprehensive simulations were performed with microwave power up to 6 kW to analyse and address all the heat loads and temperature distribution on the permanent magnet. In this article the magnetic field design and detailed innovative scheme for sextupole magnet will be presented.

Slides TUOMMH05 [2.150 MB]

WEOMMH04

Thermal Design of Refridgerated Hexapole 18 GHz ECRIS HIISI

114

T. Kalvas, H. A. Koivisto, K. Ranttila, O.A. Tarvainen
JYFL, Jyväskylä, Finland

A project is underway for constructing a new 18 GHz ECR ion source HIISI at University of Jyväskylä. An innovative plasma chamber structure with grooves at magnetic poles is being studied. This allows large chamber radius at the poles, which is relevant for the performance of the ion source while smaller radius between the poles makes space for chamber water cooling. The hexapole will be refridgerated to sub-zero temperatures to boost the coercivity and the remanence of the permanent magnet material. The hexapole structure is insulated from high temperature solenoid coils and plasma chamber by vacuum. The thermal design of the structure has been made using a thermal diffusion code taking in account radiative, conductive and convective heat transfer processes. The heat flux from plasma has been estimated using electron trajectory simulations with sensitivity analysis on the electron energy distribution. The electron simulations are verified by comparing to experimental data from 14 GHz ECR. The electron and thermodynamic simulation efforts are presented together with an analysis of the H-field vs. coersivity in the permanent magnets.

Slides WEOMMH04 [5.163 MB]

WEOBMH01

Experimental Activities with the LPSC Charge Breeder in the European Context

120

T. Lamy, J. Angot, T. Thuillier
LPSC, Grenoble Cedex, France
J. Choinski, L. Standylo
HIL, Warsaw, Poland
P. Delahaye, L. Maunoury
GANIL, Caen, France
A. Galatà
INFN/LNL, Legnaro (PD), Italy
H. A. Koivisto, O.A. Tarvainen
JYFL, Jyväskylä, Finland
G. Patti
INFN/LNS, Catania, Italy

Funding: NuPNET project (Enhanced Multi-Ionization of short-Lived Isotopes at EURISOL)
One of the Work Packages of the "Enhanced Multi-Ionization of short-Lived Isotopes at EURISOL" NuPNET project focuses on the ECR charge breeding. The LPSC charge breeder is used for experimental studies in order to better understand the fundamental processes involved in the 1+ beam capture by a 14 GHz ECR plasma. Some improvements, like symmetrisation of the magnetic field at the injection side and higher pumping speed, have been carried out on the PHOENIX charge breeder. The impact of these modifications on the efficiencies and charge breeding times are presented. In the same time, the new LPSC 1+ source developments performed in order to ease the efficiency measurements with various elements are presented.

Slides WEOBMH01 [4.982 MB]

Paper	Title	Page
MOOBMH01	Periodic Beam Burrent Oscillations Driven By Electron Cyclotron Instabilities In ECRIS Plasmas	5
	O.A. Tarvainen, T. Kalvas, H. A. Koivisto, J.P.O. Komppula, R.J. Kronholm, J.P. Laulainen JYFL, Jyväskylä, Finland I. Izotov, D. Mansfeld, V. Skalyga IAP/RAS, Nizhny Novgorod, Russia V. Toivanen CERN, Geneva, Switzerland
	Experimental observation of cyclotron instabilities in electron cyclotron resonance ion source plasma operated in cw-mode is reported. The instabilities are associated with strong microwave emission and a burst of energetic electrons escaping the plasma, and explain the periodic oscillations of the extracted beam currents. The instabilities are shown to restrict the parameter space available for the optimization of high charge state ion currents.
	Slides MOOBMH01 [2.020 MB]

MOOAMH02	High Current Proton and Deuteron Beams for Accelerators and Neutron Generators	30
	V. Skalyga, S. Golubev, I. Izotov, S. Razin, V. Sidorov IAP/RAS, Nizhny Novgorod, Russia T. Kalvas, H. A. Koivisto, O.A. Tarvainen JYFL, Jyväskylä, Finland A.V. Maslennikova, A. Volovecky Nizhny Novgorod State Medical Academy, Nizhny Novgorod, Russia
	This paper presents the latest results of high current proton and deuteron beam production at SMIS 37 at the Institute of Applied Physics. In this experimental setup the plasma is created by 37.5 GHz gyrotron radiation with power up to 100 kW in a simple mirror trap. High microwave power and frequency allow sustaining higher density hydrogen plasma in comparison to conventional ECRIS's or microwave sources. The low ion temperature, on the order of a few eV, is beneficial to produce proton beams with low emittance. Latest experiments with hydrogen and deuterium show possibility of beam formation with currents up to 550 mA at high voltages below 45 kV with normalized rms emittance lower than 0.2 pimmmrad. Such beams have a high potential for application in future accelerator research. Also in frames of the present paper it is suggested to use such an ion source in a scheme of D-D neutron generator. Such ion source can produce deuteron ion beams with current density up to 700-800 mA/cm². Generation of the neutron flux with density at the level of 7-8*10¹⁰ s⁻¹cm^-2 could be obtained in case of TiD2 target bombardment with deuteron beam accelerated to 100 keV.
	Slides MOOAMH02 [1.961 MB]

TUOMMH05	HIISI, New 18 GHz ECRIS for the JYFL Accelerator Laboratory	99
	H. A. Koivisto, P. M.T. Heikkinen, T. Kalvas, K. Ranttila, O.A. Tarvainen JYFL, Jyväskylä, Finland I. Izotov, V. Skalyga IAP/RAS, Nizhny Novgorod, Russia G. Machicoane NSCL, East Lansing, Michigan, USA T. Thuillier LPSC, Grenoble Cedex, France D. Xie LBNL, Berkeley, California, USA
	At the end of 2013 the Academy of Finland granted an infrastructure funding for the JYFL Accelerator Laboratory in order to increase beam intensities for the international user community. The primary objective is to construct a new high performance ECR ion source, HIISI (Heavy Ion Ion Source Injector), for the K130 cyclotron. Using room temperature magnets the HIISI has been designed to produce about the same magnetic field configuration as the superconducting ECRIS SUSI at NSCL/MSU for 18 GHz operation. An innovative structure will be used to maximize the radial confinement and safety of the permanent magnets. The sextupole magnets are separated and insulated from the plasma chamber providing two advantages: 1) the permanent magnets can be cooled down to -20˚C, which increases especially their coercivity and 2) makes it possible to reach higher radial field at the inner surface of plasma chamber. Comprehensive simulations were performed with microwave power up to 6 kW to analyse and address all the heat loads and temperature distribution on the permanent magnet. In this article the magnetic field design and detailed innovative scheme for sextupole magnet will be presented.
	Slides TUOMMH05 [2.150 MB]

WEOMMH04	Thermal Design of Refridgerated Hexapole 18 GHz ECRIS HIISI	114
	T. Kalvas, H. A. Koivisto, K. Ranttila, O.A. Tarvainen JYFL, Jyväskylä, Finland
	A project is underway for constructing a new 18 GHz ECR ion source HIISI at University of Jyväskylä. An innovative plasma chamber structure with grooves at magnetic poles is being studied. This allows large chamber radius at the poles, which is relevant for the performance of the ion source while smaller radius between the poles makes space for chamber water cooling. The hexapole will be refridgerated to sub-zero temperatures to boost the coercivity and the remanence of the permanent magnet material. The hexapole structure is insulated from high temperature solenoid coils and plasma chamber by vacuum. The thermal design of the structure has been made using a thermal diffusion code taking in account radiative, conductive and convective heat transfer processes. The heat flux from plasma has been estimated using electron trajectory simulations with sensitivity analysis on the electron energy distribution. The electron simulations are verified by comparing to experimental data from 14 GHz ECR. The electron and thermodynamic simulation efforts are presented together with an analysis of the H-field vs. coersivity in the permanent magnets.
	Slides WEOMMH04 [5.163 MB]

WEOBMH01	Experimental Activities with the LPSC Charge Breeder in the European Context	120
	T. Lamy, J. Angot, T. Thuillier LPSC, Grenoble Cedex, France J. Choinski, L. Standylo HIL, Warsaw, Poland P. Delahaye, L. Maunoury GANIL, Caen, France A. Galatà INFN/LNL, Legnaro (PD), Italy H. A. Koivisto, O.A. Tarvainen JYFL, Jyväskylä, Finland G. Patti INFN/LNS, Catania, Italy
	Funding: NuPNET project (Enhanced Multi-Ionization of short-Lived Isotopes at EURISOL) One of the Work Packages of the "Enhanced Multi-Ionization of short-Lived Isotopes at EURISOL" NuPNET project focuses on the ECR charge breeding. The LPSC charge breeder is used for experimental studies in order to better understand the fundamental processes involved in the 1+ beam capture by a 14 GHz ECR plasma. Some improvements, like symmetrisation of the magnetic field at the injection side and higher pumping speed, have been carried out on the PHOENIX charge breeder. The impact of these modifications on the efficiencies and charge breeding times are presented. In the same time, the new LPSC 1+ source developments performed in order to ease the efficiency measurements with various elements are presented.
	Slides WEOBMH01 [4.982 MB]