Metastable states’ population densities in Gd atomic beam at high‐rate evaporation by electron beam heating

• Published in: Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films Vol. 11; no. 4; pp. 1516 - 1521
• Main Authors: Nishimura, Akihiko, Arisawa, Takashi, Ohba, Hironori, Shibata, Takemasa
• Format: Conference Proceeding Journal Article
• Language: English
• Published: Melville, NY American Institute of Physics 01-07-1993
• Subjects: Atomic, molecular and charged-particle sources and detectors; Charged-particle beam sources and detectors; Exact sciences and technology; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Isotope separation and enrichment; Nuclear engineering and nuclear power studies; Nuclear physics; Physics; GADOLINIUM; METASTABLE STATES; ATOMIC BEAMS; LASER SPECTROSCOPY; ENERGY−LEVEL DENSITY; VACUUM EVAPORATION; ATOMIC CLUSTERS; ELECTRON GUNS; Gd; Proceedings; Laser isotope separation; Electron beams; Atomic beams; Metastable states; Gadolinium; Experimental study; Population density; Electron beam evaporation
• ISSN: 0734-2101; 1520-8559
• DOI: 10.1116/1.578694

Metastable states’ population densities in gadolinium atomic beams, which were produced by an axial electron beam gun, were measured by laser absorption spectroscopy at the atomic densities on the order of 1012 atoms/cm3. The following results were obtained. (1) The atomic excitation temperature derived from the metastable states distributions is considerably lower than the evaporation surface temperature. With increasing evaporation rates, the atomic excitation temperature decreased to about 500 K. (2) The densities of both ground and first metastable states increased linearly with the deposition rates as measured by a quartz crystal sensor on the beam axis, which indicates that the atomic beam is almost free from the cluster formation caused by rapid expansion into a high vacuum.