Production of a Carbon Stripper Foil by an ECR Plasma
ECRプラズマによる炭素荷電交換フォイルの生成
Masaru Yamanaka, Toshiro Kasuya, Masahiro Yoshimoto and Motoi Wada
山中 優1，粕谷俊郎1，吉本政弘2，和田 元3
1

Graduate School of Engineering, Doshisha University, Kyotanabe,Kyoto610-321, Japan
2J-PARC, Japan Atomic Energy Agency, Tokai, Naka, Ibaraki 319-1195, Japan
3
Faculty of Life and Medical Sciences, Doshisha University, Kyotanabe,Kyoto610-321, Japan1
同志社大学大学院工学研究科，3同志社大学生命医科学部，〒610-0321 京田辺市多々羅都谷1-3
2J-PARCセンター，〒319-1195 茨城県那珂郡東海村
Nanocrystalline diamond thin films can be durable agains proton radiation like the condition of a carbon
stripper foil for the accelerator rings. Not only nanocrystalline diamond, variety of carbon thin films likecarbon nanotubes and carbon nanowalls can be prepared by utilizing plasma enhance chemical vapor
deposition (PECVD) processes. Sub-atmospheric pressure electron cyclotron resonance (ECR) plasma
can produce low temperature hydrogen diluted methane plasma useful for rapid synthesis of carbon
material thin films. A hydrocarbon generator based upon the process of hydrogen dissociation on heatedcarbon surface has been being developed to prepare carbon films coupled to an ECR-PECVD device.

1. Introduction
Low carbon content hydrocarbon plasma can beproduced without directly introducing hydrocarbon
gas into a discharge. By heating up solid carbon andexposing it to hydrogen plasma, hydrocarbons are
released from the surface by the process ofchemical sputtering. Variety of carbon deposits arefound formed in fusion experiment devices throughthis mechanism, and this concept is utilized toproduce carbon thin films under plasma enhanced
chemical vapor deposition (PECVD) conditions.
2. Experimental set up
2-1. ECR plasma source
Low temperature reactive plasmas can beproduced with electron cyclotron resonance (ECR)
condition. Thus, an ECR-PECVD device as shownin Fig.1 is being assembled equipped with a heatedcarbon hydrogen dissociator. The equipment has an
infrared heater to keep temperature of the substrate
at 1000 K temperature. A heat shield is arranged
inside of the chamber to reduce heating of theinside wall of the chamber. A ring shaped solidcarbon is located right above the heated deposition
target, and the magnetized ECR plasma runsthrough the center of the carbon ring.
Anenhanced production of hydrocarbon takes place atthe surface of the carbon dissociator.
2-2. Carbon dissociator
Performance of a heated carbon hydrogendissociator is examined with the dissociatorstructure shown in Fig. 2. It has a 3 mm diameterhydrogen conduit at the center of 10 mm diameter
55 mm long carbon rod. A 0.6 mm diameter 150

mm long tungsten wire is wound around the rod as
an infrared heater, and 50 mm radius carbon heatshield blocks the infrared radiation from coming outof the dissociator.

Fig.1. Schematic diagram of ECRPECVD.

3. Preliminary results
The dissociator had been operated without
plasma up to about 1000K. Signal of a quadrupole
mass analyzer had clearly indicated sizable
reduction in CO signal and enhancement of H2O
signal in accordance with the introduction of H2 gas
into the dissociator. Performance test with H2
plasma is being carried out.

Fig.2. Schematic diagram of carbon dissociator.