A time-of-flight mass spectrometer for measurement of secondary ion mass spectra

Abstract

A time-of-flight mass spectrometer has been constructed at the University of Manitoba. In this instrument, bursts of alkali-metal ions of ∼10 ns duration strike a thin layer of organic material deposited onto a metal backing. The secondary ions produced are accelerated across a fixed potential ⩽10 kV, then travel down a flight tube 1.6 m long. Measurement of the time of flight determines the mass-to-charge ratio of the ions. Mass spectra from biomolecules with masses up to 1355 u have been measured with the instrument. They exhibit significant quasimolecular ion peaks.