22P155-P
Development of a Beam Profile Monitor Using a Negative Ion Probe Beam forHigh Intensity Positive Ion Beams
負イオンプローブビームを用いたビームプロファイルモニターの開発
Katsuhiro Shinto1, Motoi Wada2, Tomoaki Nishida2, Masashi Kisaki3,
Katsuyoshi Tsumori3, Masaki Nishiura3, Osamu Kaneko3 and Mamiko Sasao4
神藤勝啓1, 和田元2，西田睦聡2，木崎雅志3，
津守克嘉3，西浦正樹3，金子修3，笹尾眞實子2,4
1

Japan Atomic Energy Agency (JAEA), 2-166 Obuchi Omotedate, Rokkasho, Kamikita, Aomori 039-3212, Japan
2Doshisha University, 1-3 Tatara Miyakodani, Kyotanabe, Kyoto 610-0394, Japan
3
National Institute for Fusion Science (NIFS), 322-6 Oroshi, Toki, Gifu 509-5292, Japan
4
Tohoku University, 6-6 Aoba, Aramaki, Aoba, Sendai, Miyagi 980-8579, Japan1

日本原子力研究開発機構 〒039-3212 青森県上北郡六ヶ所村尾駮表舘2-166
2同志社大学 〒610-0394 京都府京田辺市多々羅都谷1-33
核融合科学研究所 〒509-5292 岐阜県土岐市下石町322-6
4東北大学 〒980-8579 宮城県仙台市青葉区荒巻字青葉6-6

We have proposed a negative ion beam probe system as a new scheme to diagnose beam profiles of highpower positive ion beams. We show the present status of the proof-of-principle experiment for the negative
ion beam probe system performed at NIFS NBI test stand. A negative hydrogen ion source which produces
a rectangular shape beam was installed and the total current of H- beam extracted from the ion source wasmeasured. We obtained the total H- beam current of 10 A with the beam energy of 3 kV.

1. Introduction
In order to diagnose beam profiles of highintensity positive ion beams in a high radiation
field environment such as the International
Fusion Materials Irradiation Facility (IFMIF)
linear accelerators [1], we have been developing anegative ion beam probe system as a new tool.
We designed, assembled and tested a compact
KAMABOKO type H- ion source at Doshisha
University for the proof-of-principle experiment of
the negative ion beam probe system [2].
After the beam test at Doshisha University, theH- ion source was moved to National Institute forFusion Science (NIFS). It has attached on astrongly focusing and high-intensity He+ beamdiagnostic chamber at NIFS Neutral Beam
Injection (NBI) test stand in order to validate thesystem feasibility [3]. In this summer, weperformed the H- beam extraction at NIFS NBItest stand. In this article, we show theexperimental results of the beam test and future
prospects.
2. Experimental setup and results
Figure 1 is a photograph of the compact
KAMABOKO type H- ion source attached on thediagnostics chamber for the He+ beam extracted
from the strongly focusing and high-intensity He+

He+ ion source

He+ beam diagnostic
chamber

H- ion source

Fig.1. A photograph of the compact KAMABOKO type
H- ion source attached on the diagnostic chamber for thestrongly focusing and high-intensity He+ ion source.

ion source. The H- ion source is designed toproduce the H- beam with a rectangular shape of 70mm × 2 mm.
In order to measure the total H- beam current
extracted from the ion source, a Faraday cup withthe rectangular aperture of 100 mm × 10 mm wasinstalled in the diagnostic chamber. The distance
between the exit of the H- beam extraction apertureof the H- ion source and the entrance of the Faraday
cup aperture is about 1,000 mm.
Figure 2 shows an experimental result of the Hbeam measurement. The extracted H- beam current
was obtained about 10 A at the maximum
discharge current of 2.5 A which was limited by thepower supply and by increasing the hydrogen gas
pressure in the ion source and optimizing the lens
voltage applied to the intermediate electrode in theextraction system of the H- ion source.

Gas pressurein the H ion source-4
7.5x10 Torr
-4

4.9x10 Torr

9-4

3.3x10 Torr

6-

Measured H beam current IH- (A)

12300

1

234

Beam extraction voltage Vext (kV)Fig.2. Measured H- beam current extracted from thecompact KAMABOKO type H- ion source as a functionof the extraction voltage. Hydrogen discharge voltage
and current in the ion source, Vd = 70 V and Id =2.5 A,
respectively.

3. Summary and future plan
We have installed the compact KAMABOKO
type H- ion source in the beam diagnostic chamber
for the strongly focusing and high-intensity He+ ion
source at NIFS NBI test stand in order to validate
the active beam probe technique as a new tool forthe beam profile diagnostics of high intensity
positive ion beams and measured the total H- beam
current extracted from the H- ion source. Weobtained the H- beam current of 10 A with thebeam energy of 3 kV. In this winter, we will

perform an experimental study for theproof-of-principle of the new spatial beam profile
monitor tool by crossing this H- beam to the He+
beam perpendicularly.
Acknowledgments
This work was supported by Japan Society
for the Promotion of Science Grant-in-Aid for
Scientific Research (KAKENHI) (C) 21560864.
It was also supported by NIFS collaborative
program NIFS10KLER002. Authors appreciate
the continuous encouragement of Dr. Yoshikazu
Okumura in JAEA. They also thank Mr. EijiAsano and Ms. Hiromi Kato in NIFS for theirtechnical support.
References[1] The IFMIF International Team, an activity of theInternational Energy Agency (IEA), Implementing
Agreement for a Program of Research andDevelopment on Fusion Materials: IFMIF
Comprehensive Design Report, January 2004.
[2] K. Shinto, M. Wada, T. Nishida, Y. Demura, D.
Sasaki, K. Tsumori, M. Nishiura, O. Kaneko, M.
Kisaki and M. Sasao: AIP Conf. Proc. 1390 (2011),p.675.
[3] K. Shinto, A. Okamoto, S. Kitajima, M. Sasao, M.
Nishiura, O. Kaneko, S. Kiyama, H. Sakakita, Y.
Hirano and M. Wada: Proc. of the 10th European
Particle Accelerator Conference (EPAC’06),
Edinburgh, Scotland, 2006, pp.1726.