PHOTOEMISSION ELECTRON-IMPACT IONIZATION IN TIME-OF-FLIGHT MASS-SPECTROMETRY - AN EXAMINATION OF EXPERIMENTAL CONSEQUENCES

The use of photoemission electron impact ionization in time-of-flight mass spectrometry is examined. It is found to complement laser ionization by providing many of the advantages of electron impact ionization. Some ions are more easily produced by photoemission electron impact ionization. Under certain conditions, these ions can act as an impediment to laser ionization experiments. Methods for distinguishing between ions produced by laser ionization and photoemission electron impact ionization are presented. A new source, designed for simple conversion between these two ionization methods, is presented. This source is easily adapted to the many laser ionization time-of-flight instruments already in use.