Abstract:
Due to the mass spectrometer having a simple structure, fast scanning speed, and large mass detection range, it is the most commonly used in-situ analysis instrument in deep space exploration missions. At the same time, mass spectrometry is a means of directly analyzing the composition of matter, so it has an irreplaceable advantage in solving the problem of lunar water ice detection. In the process of measuring water vapor with a mass spectrometer, water vapor causes challenges to the accuracy of calibration and measurement results, as it has strong adsorption which is difficult to completely remove. This article introduces current research on water abundance calibration methods for mass spectrometers, including the preparation of standard calibration water vapor and optimization of the calibration process. Methods for preparing standard calibration water vapor can be divided into temperature-controlled expansion method, flow meter method, and chemical reaction method. Methods for optimizing the calibration process can be divided into volume expansion method, constant conductance method, calibration based on other gases method, and optimizing calibration procedure. Methods are explained that include calibration of mass spectrometer and water measurement in deep space exploration missions. In response to the mission requirements of the fourth phase of the China Lunar Exploration Project, a calibration method based on small hole constant conductance was proposed to achieve mass spectrometry calibration of water vapor. Provide a reference for the technical development of mass spectrometer calibration of water vapor in deep space environments.