The invention relates to the technical field of instruments and meters, in particular to a small-sized double-focusing
mass spectrum imaging system for space and a use method, the
system comprises an
ion source, a coding plate, an electrostatic analyzer, a magnetic analyzer and an FOP
detector, the
ion source adopts a symmetrical
magnetic field structure, and a
cathode emission device and a
hot filament are respectively located at two ends of the
ion source; the coding plate is arranged right in front of the
ion source; the electrostatic analyzer is composed of two coaxial cylindrical electrodes; the
magnetic field structure of the magnetic analyzer is a direct asymmetric fan-shaped
magnetic field; the electrostatic analyzer and the magnetic analyzer are combined in a reverse serial connection manner; the FOP
detector adopts a micro-channel plate + fluorescent screen +
CMOS camera imaging mode. According to the invention, the limitation of large sizes of ion beams and imaging light spots thereof under a conventional single-slit outlet structure of a
mass spectrometer is overcome by adopting a coding aperture mode, so that the
mass resolution of the
mass spectrum imaging device is remarkably improved, the sensitivity is high, the imaging speed is high, the
signal-to-
noise ratio is high, and the detection of lower-content substances is realized.