How the Ion Source Filament Works

Abstract

The invention provides a working method of an ion source filament. The working method of the ion source filament comprises the following steps: (A1) when the self-test period of the ion source is reached, the sample gas is turned off; (A2) the standard gas is fed into the ion source, obtain the maximum ion peak signal intensity I in the spectrogram max , the minimum ion peak signal intensity I min (A3) analysis ion peak signal intensity I max , I min ; (A4) Close the calibration gas, open the sample gas, and measure normally; record the adjusted filament working voltage U n , the regulated total voltage ΔU n , the time Δt from the last adjustment of the filament working voltage n ; (A5) According to the recorded ΔU 1 , ΔU 2 …ΔU n and the corresponding Δt 1 , Δt 2 …Δt n , fit ΔU=f(t); obtain the remaining use time of the filament Δt: U max -U n =f(Δt). The invention has the advantages of accurate prediction of remaining life and the like.

Description

technical field [0001] The invention relates to mass spectrometry, in particular to the working method of the ion source filament. Background technique [0002] The ion source of the mass spectrometer used in the online mass spectrometer is mainly the electron bombardment ion source, that is, the EI source. [0003] figure 1 A schematic diagram of the structure of the external ion source is given schematically, such as figure 1 As shown, in a vacuum environment, the gas to be measured is introduced into the ion vacuum chamber, and the filament emits an electron flow to bombard the gas to be measured, and then ionize the gas to be measured. The ionized fragment ions pass through the extraction electrode, focusing electrode, acceleration After the electrodes enter the mass filter for separation and analysis. The disadvantages of this way of working are: [0004] (1) The filament current is too large, basically around 1A, resulting in frequent replacement of the filament, a...

AI Technical Summary

Problems solved by technology

[0004] (1) The filament current is too large, basically around 1A, resulting in frequent replacement of the filament, and the filament needs to be replaced after one year of use;

[0005] (2) Due to the continuous online detection, the measured gas contains a large amount of impurities, and the ion source is easily contaminated by the measured gas after a period of use, but it is impossible to accurately determine the replacement time of the filament. If the replacement is too late, the measurement of the instrument will not be accurate. Early leads to waste and frequent replacement

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