Abstract: Ion-Retarding Lens to Improve the Abandance Sensitivity of Mass SpectrometerLu Horigyou;Xiao Meiqin(China Institute of Atomic Energy,Beijing 102413,China)Abstract:This report describes the design and the calculation of an ion-retarding lens system which is used to increase the abundance sensitivity of MAT-260 mass spectrometer. By using numerical method,for the ion beam of 10keV,the ion- beam with energy disppersion △V≥38eV can be retarded to reduce the tails which are detected on both side of the mass position of high-abundance isotope,so that the low-abundance isotope within one mass unit can be detected.The retarding lens is placed between the spectrometer defining slit and the detector,it is simple and relatively inexpenseve,it can not only increase the abundance sensitivity,but also play a certain role in beam focusing.It is suitable for improving single-order mass spectrometer and has been used.Keywords:energy disppersion,retarding lens,numerical calculation