| 摘要 |
PURPOSE:To prevent the intrusion of test gas into the part other than a masking space, by injecting a gas other than helium or the like for testing in the space formed by flexible members which hermetically seal an object to be tested in a double mode. CONSTITUTION:An observing window 1, which is the object to be tested, is tightly sealed by the flexible, tightly sealing cover members 2 and 3 such as vinyl in the double mode. In the space 5 formed by these members 2 and 3, the gas such as nitrogen other than the test gas such as helium or hydrogen is supplied and pressurized through a pipe 4. Under this state, the masking space 7 between the inner member 2 and the window 1 is evacuated through an exhaust pipe 6 to obtain a vacuum state. Thereafter, the test gas such as helium is injected into the space 7 by a supply pipe 8. This is repeated three times and the helium gas in the space 7 is well substituted. Then the amount of leakage of the window 1 is measured by using a helium leakage detector, a mass analyzing device, and the like. The intrusion of the helium gas to the part other than the masking space is prevented in this method. Thus the amount of the leakage can be accurately measured. |
