DESIGN CONSIDERATIONS IN ENERGY-RESOLVED TIME-OF-FLIGHT MASS-SPECTROMETRY

We report the design, construction and performance of an energy resolved time-of-flight (ER-TOF) mass spectrometer. The system consists of a linear TOF coupled in parallel to the electric sector of a large double-focussing magnetic-sector mass spectrometer. The use of lensing between the TOF and the electric sector is discussed with respect to the required beam conditions. Ion transmission through the electric sector is treated theoretically, especially with respect to time-of-flight. Preliminary experimental results from the instrument using matrix-assisted laser desorption-ionisation are presented and discussed, with particular regard to the fragmentation of large ions.