ECRIS-2014 - List of Authors (Ranttila, K.)

Paper

Title

Page

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]

Paper	Title	Page
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]