PURPOSE: To enable satisfactory measurement of a partial pressure even in an ultra-high vaccum region without using an electron multiplier by impressing AC potential to the electrode of an ion source part of a quadrupole mass spectrometer and detecting the AC ion by phase detection.
CONSTITUTION: A quadrupole analyzing tube consists of an ion source part 1, a quadrupole analyzing part 2 and a detecting part 3. A signal of a low frequency is impressed from an oscillator 5 via a mixer 6 to an optional electrode, for example, grid electrode 12, of the part 1. The ion made in the part 1 is then modulated and enters the collector electrode 33 of the part 3 by passing through the part 2. The ion current signal entering the electrode 33 is amplified by a preamplifier 7, by which phase detection is accomplished and the DC voltage is generated according to the magnitude of the ion current. Said voltage is indicated on a meter 10. The modulating voltage to be impressed to the grid electrode 12 is preferably the peak value and below the acceleration voltage.
KOMAKI SHIYOUJIROU
MIYAMOTO MASAO
ITOU TAKAO
WATANABE FUMIO
| JPS56132758A | 1981-10-17 |