Ion optics of the LAMAS-10 laser time-of-flight mass spectrometer

In laser time-of-flight mass spectrometers, satisfactory resolution by weight is achieved for a fixed initial kinetic energy acquired by the ions in the plasma. The integration of mass spectra in a wide energy range intended for obtaining satisfactory results of analysis leads to a 3–5-fold reduction of the resolving capacity. In the case of the LAMAS-10 device, the resolution for W = 50–300 eV energy dispersion of the ions varies from R ∼ 1000 (for W = 300 eV) to R ∼ 150 (for W = 50 eV), such values being insufficient for quantitative elemental analysis. It has been demonstrated that the main reason for the differences in the resolution values for LAMAS-10 are time aberrations by energies in the laser plasma drift space. The modification of the ion optics theory for LAMAS-10 allows the determination of the principles of the influence of the initial ion energies generated in the laser plasma on the resolution. The dependence of the conditions of the time focusing of ions by energies has been determined in a wide range of the initial values. This dependence provides software-controlled readjustment of the time focusing before the registration of the mass spectra for each initial ion energy. When time focusing of the ions was performed in a wide range of the initial energies, the resolution increased to R = 1300 at W = 50 eV, such parameters providing the quantitative analysis of solid bodies and powders.