Calibration of a time-of-flight machine for molecular beam studies

Abstract

A time-of-flight machine for the velocity analysis of molecular beams is described together with an experimental investigation of systematic errors. A velocity selecting chopper is used to measure all delay times, including the delay in the beam detector due to the extraction time from the ionizer and the flight time of the ions in the quadrupole mass filter. With the ionizer no memory effects occur at emission currents smaller than 1 mA. Memory effects in the detector chamber due to the direct reflection of beam particles are eliminated.