ION-OPTICAL SOLUTIONS IN TIME-OF-FLIGHT MASS-SPECTROMETRY

Time-of-flight mass spectrometers are able to cover mass ranges to around a half a million Da. The mass resolution of these instruments has been improved drastically by incorporation of electrostatic mirrors. The ion-optical solutions enabling these achievements and other promising features are discussed in terms of First- and second-order space focusing in time for linear drift time-of-flight mass spectrometers; velocity focusing by time lag; ion-packet bunching in post-source impulse focusing; first- and second-order energy focusing in time, in single- and double-stage homogeneous electrostatic mirrors with normal and oblique ion incidence; gridless designs; perfect time focusing in parabolic potential and axial symmetry; cylindrical ion mirrors and toroidal electrostatic deflectors as time-of-flight mass analyzers; three electrostatic sector geometry applied in secondary ion microscopy and four toroidal sector systems for tandem mass spectrometry; poloidal electrostatic sectors. Estimation of time-of-flight mass spectrometer performance limits is discussed and the stable as well as the metastable peak shapes found in time-of-flight mass spectra.