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

We report the design, construction and performance of an energy resolv ed time-of-flight (ER-TOF) mass spectrometer. The system consists of a linear TOF coupled in parallel to the electric sector of a large doub le-focussing magnetic-sector mass spectrometer. The use of lensing bet ween 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-assi sted laser desorption-ionisation are presented and discussed, with par ticular regard to the fragmentation of large ions.