Velocity distributions in high density gadolinium atomic beam produced with axial electron beam gun

The parallel and perpendicular velocity distributions of a gadolinium atomic beam produced with an axial electron beam gun have been measured by a Doppler-shift technique and a Doppler limited absorption spectroscopy, respectively. The atomic density of 1018~1019atoms/m3 at a laser irradiated zone was sufficient for the process, such as an atomic vapor laser isotope separation. The atomic beam velocity of 800 m/s was obtained by a free expansion near an evaporation surface. This velocity, however, was 100 m/s slower than that we had measured with a magnetic transverse electron beam gun in a previous experiment. The reasons for the slower velocity in this experiment than that in the previous one are discussed. In keeping with the deposition rate, the parallel translational temperature rapidly decreased to 200 K, while the perpendicular translational temperature gradually increased and approached to the parallel translational temperature. This result suggested that the collisional region where both translat...