| 摘要 |
PROBLEM TO BE SOLVED: To easily and accurately detect the damage of an ion beam vacuum discharge window by obtaining the film thickness and composition of the window from the energy distribution of particles scattered from the window. SOLUTION: When a hydrogen ion (proton) beam having an energy of 1.5MeV is, for example, converged to the width of about 50μm, passed through a discharge window using a polyimide film having a thickness of 7.5μm from vacuum and taken out into oxygen gas at about 1atm, the proton scattered from the window is detected by a semiconductor particle detector disposed in the direction of about 150 degrees with respect to the advancing direction of the beam to obtain its energy distribution. Then, the composition and film thickness of the window are examined from the distribution by a Rutherford back-scattering(RBS) method, and the damage due to the ion beam emitting is detected. Thus, the fracture period of the window can be predicted without interrupting the ion beam emission, and the damage of the apparatus due to the fracture of the window can be prevented.
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