MAGNETIC FIELD DEFLECTION MASS ANALYSIS TUBE AND LEAK DETECTOR

摘要

PROBLEM TO BE SOLVED: To provide a mass analysis tube for a leak detector allowing pressure to be surely obtained without causing an increase in a parts count and being optimum for accurately measuring a leak value independently of the continued use period of the leak detector. SOLUTION: This magnetic field deflection mass analysis tube 2 includes: an ion source 23 comprising a tube 21 with a gas inlet 22 bored therein and comprising a filament 23a and a grid 23b in the tube while ionizing gas molecules introduced from the gas inlet; a first ion collector 25 for collecting helium ions; and a magnet 24 provided between the ion source and the ion collector in the tube to form a magnetic field that deflects ions emitted from the ion source under prescribed acceleration voltage according to the mass number thereof to guide only helium ions to the ion collector. A second ion collector 27 is installed around the ion source, and positive ions generated in the ion source are collected in the second ion collector. COPYRIGHT: (C)2011,JPO&INPIT