Effects of methane on multi-wall carbon nanotube field emitter for a low energy ion source

Abstract

A low energy ion source based on carbon nanotube (CNT) electron emitter was constructed for calibrating the ion-mode of mass spectrometer or other ion detectors. The field emission properties of CNT for CH4 were tested in the experiments. The field emission current increases along with the pressure rise of CH4 from 10−6 Pa to 10−4 Pa in a short time, but the degradation of field emission current was found in nearly 2 hours storage in CH4 with pressure of 10−4 Pa. While the CH4 was introduced as the operation gas in ion source, the maximum CH4+ ion current of 45 pA, and the sensitivity of 1.76 Pa−1 with the relative standard deviation (RSD) 4.9% could be obtained.

Keywords

• Ion source
• Field emission
• Gas adsorption
• Carbon nanotube