| 摘要 |
PCT No. PCT/JP95/00284 Sec. 371 Date Nov. 17, 1997 Sec. 102(e) Date Nov. 17, 1997 PCT Filed Feb. 24, 1995 PCT Pub. No. WO96/26426 PCT Pub. Date Aug. 29, 1996A method of measuring external leakage, which comprises the steps of introducing a first gas different from main component gasses of an external atmosphere into a pipe having a leak, adding H2 gas (or H2-containing gas) to the first has at a down-stream point, and measuring gas components entering from the external atmosphere of the leak by an atmospheric ionization mass spectrometer (atmospheric pressure ionization mass spectrometer) at a further downstream point (for example, N2H+ is detected when the external atmosphere is the N2 gas). A method of measuring the external leakage of a gas supply piping line having a plurality of branch piping lines comprises the steps of introducing H2 gas (or a H2-containing gas) into at least one of the branch piping lines, introducing a first gas different from main component gases of an external atmosphere into the rest of the branch piping lines, and measuring gas components entering from the external atmosphere by the atmospheric pressure ionization mass spectrometer at a downstream point of the branch portion. The present invention can measure the external leakage very simply and with high levels of sensitivity and accuracy. Particularly, the present invention can be suitable applied to the cases where an inspection portion is elongated or branched such as feed pipe of a semiconductor plant.
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