Characteristics of hydrogen supersonic cluster beam generated by a Laval nozzle

Formation of a hydrogen cluster jet using a Laval nozzle has been investigated in the temperature range from 120 K to 300 K. Time-resolved 2-D images of Rayleigh scattering due to clusters have been measured by a fast charge coupled device camera. The scattering signal from hydrogen clusters is detected when the temperature is below 178 K, as expected from a calculation result of the condition to produce clusters. The scattering signal intensity is inversely proportional to the fifth power of the gas temperature and cubic dependence on the backing pressure as expected from an available cluster model. (author)