The neutral particle composition of Al blow-off beams was studied using a time-of-flight mass spectrometer (TOFMS) with UV laser photoionization. The neutral components of the Al beam were injected into the MS and the particles were ionized by the UV laser pulse. The ions were mass separated by a reflectron type TOFMS so as to find out if there were multi-atomic components in the beam besides the atoms. Two kinds of neutral particles were found in the blow-off beam by this method, namely Al atoms and Al2 dimers. Clusters consisting of more than two atoms have not been found. The delay time between the ruby and excimer laser pulses (i.e. the generation of the beam and the ionization of the neutral particles) was varied in order to determine the velocity distribution of the particles. The velocity distributions of both constituents showed a double peaked structure indicating the presence of particle packets originating from different sources. The first and second peaks of the velocity distributions could be fairly well fitted by Maxwellian distribution functions.
ASJC Scopus subject areas
- Condensed Matter Physics