Asymmetric quadrupole-rod mass analyzer

The invention, which belongs to the technical field of the mass analyzer, particularly relates to an asymmetric quadrupole-rod mass analyzer formed by four cylindrical electrodes with different diameters. One pair of electrodes have large diameters and the other pair of electrodes have small diameters; and the cylindrical surfaces of the four cylindrical electrodes form a concentric circle in an encircling mode. When the diameters of the electrodes and the diameter of the encircled concentric circle are in a certain proportion, the quadrupole electrode layer will generate electric field distribution with a quadrupole electric field oriented and other high-order electric fields assisted under the effect of the radio frequency voltage. On the basis of the electric field distribution, constraint processing and mass analyzing are carried out on an ion entering the quadrupole electrode layer. Compared with the traditional quadrupole electrode system with four identical electrodes, the provided mass analyzer has th