LASER-DRIVEN FLOW REACTOR AS A CLUSTER BEAM SOURCE

A novel technique for the production of expansion-cooled cluster beams from materials with low vapor pressure is presented. The clusters are produced in a flow reactor from gas phase reactants by aggregation of CO2-laser-induced decomposition products. By introducing a conical no zzle into the reaction zone, they are extracted into a molecular beam apparatus and analyzed with a time of-flight mass spectrometer. Depend ing on the type of CO2-laser employed, the source can be operated in t he pulsed or continuous mode. The generation of carbon and silicon clu sters is demonstrated by decomposing gaseous C2H2 and SiH4, respective ly. The laser-driven cluster course is also employed to generate fulle renes and nanosized silicon particles. (C) 1995 American Institute of Physics.