This thesis describes a non-magnetic mass spectrometer incorporating the following components: a heated filament source, an electrostatic energy analyser, and a time-of-flight velocity analyser. The last component measures the time required for an ion to go between two small condensers by means of a radio frequency voltage applied to the condensers. If an ion passes successively through both condensers when the field in them is zero, it is collected and detected. It is then possible to relate the e/m to the frequency of the applied voltage when the energy of the ion and the distance between the centres of the condensers is known. Theory is presented which permits the calculation of resolution and current intensities. The values so obtained are realized experimentally. / Thesis / Master of Science (MSc)