Performance evaluation of a miniature magnetic sector mass spectrometer onboard a satellite in space

With the rapid development of space technology in China, it is urgent to use mass spectrometer to detect the space environment. In this work, a space miniature magnetic sector mass spectrometer is evaluated, which consists of three subsystems: (1) physical unit, (2) electric control unit, (3) and high voltage power. It has 90° magnetic sector-field analyzer with double trajectory, in which a trajectory measurement range is from 1 to 12 amu, the other range is from 6 to 90 amu.The mass spectrometer has two work models, one is used to measure space neutral gas when the filament of mass spectrometer ion source turned on, the other is used to measure space charged ions when the filament turned off. The absolute resolution of this device is less than 1 amu, the minimum detectable ion current is about 10−13 A, and the sensitivity is 10−6 A/Pa (N2). Its overall size is 170 mm × 165 mm × 170 mm, its weight is 4.5 kg, and its power consumption is 18 W. A series of environmental adaptability tests, including high and low temperature cycle, shock, vibration, thermal vacuum cycle, were carried out on the ground before launching, and sensitivity and peak position were also calibrated on the ground. In November 2012, the mass spectrometer was carried by an experimental satellite to 499 km sun synchronization and is still working right now. It successfully detected the atmosphere compositions both in the satellite orbit and gas-emitted from satellite, including O, He, 12CO2, 13CO2, H2, N2, O2, H2O, and so on.

Study of vaporization of LiI, LiI/C70, LiI/LiF/C70 from the Knudsen cell located into ionization chamber of the mass spectrometer

The vaporization of LiI, LiI/C70 and LiI/LIF/C70 were studied using a Knudsen cell located into ionization chamber of a magnetic sector mass spectrometer in a temperature range from 350 ?C to 850 ?C. ?s the ion species, LinI+ (n = 2, 3, 4, and 6) were identified from a mixture LiI/C70. While the clusters LinI+ and LinF+ (n = 2 - 6) were detected from a mixture LiI/LiF/C70. The intensities of LinI+ were higher than the emission of LinF+ cluster when the ratio of LiI to LiF was 2:1. By contrast, the emission of the LinF+ is favored when the ratio of LiI to LiF was 1:2. These results show that the vaporization of a mixture LiI/LIF/C70 from the Knudsen cell located into ionization chamber of the mass spectrometer represents an efficient and simple way to obtain and investigate clusters of the type LinX, X-F, I. In this work it has also been shown that the trend of the ln (Intensity, arbit. units) versus temperature for all LinI+ clusters before and after the melting point of LiI was not same. It suggested that the way of the formation of these clusters can be different due to changes in temperature.