| 摘要 |
PROBLEM TO BE SOLVED: To provide the analyzing tube of a helium leak detector, which alleviates the inhibition of helium ion orbit caused by the scattered ions of hydrogen lighter than helium or the like and can measure the helium ions in high accuracy stably even in the measurement of the minute helium ion current. SOLUTION: In this analyzing tube, each orbit of various kinds of ions emitted from an ion source 15 is determined with a magnetic field, a wall part 11 for separating the ions is provided at a position shielding the orbit of the ion, a slit 13, which passes only the helium ions, is formed at a place in correspondence with the orbit 21 of the helium ions at the wall part 11, and the tube has the magnetic-field type for the helium leak detector so that only the helium ions are detected. In this case, slits 23 and 24 for passing these ions are formed at places in correspondence with the orbit of the ions lighter than the helium ions at the wall part for separation. |
