A compact sector-type multi-turn time-of-flight mass spectrometer ‘MULTUM II’

A new compact sector-type multi-turn time-of-flight mass spectrometer ‘MULTUM II’ was constructed. The ion optical system was simplified compared with former sector-type multi-turn time-of-flight mass spectrometer ‘MULTUM Linear plus’. The multi-turn part of the new instruments consisted of only four toroidal electric sector fields. The mean radius of cylindrical electric sectors was 50 mm and the deflection angle was 157.1°. The total flight path length of one cycle was 1.308 m. All ion optical elements were hanged on the top plate (480 mm×380 mm) of the vacuum housing. Variations of the mass resolution and ion transmission according to the number of cycles were determined. The mass resolution of 33,000 was achieved after 150 cycles.