Pulsed metastable atomic beam source for time-of-flight applications
A metastable atomic beam source was developed utilizing pulsed helium and argon nozzle beams. A coaxial electron gun, which can be used in a pulsed as well as in a continuous mode, excites the noble gases to their metastable states by electron bombardment in the direction of propagation of the ground-state atoms. In contrast to former work, the electron beam is controlled and accelerated by a combination of three hemispherically shaped tungsten grids. With continuous electron gun operation the source produces a metastable flux of about 10/sup 15/ atoms/sr s for helium and argon under optimum expansion conditions. Applying short electrical pulses to a control grid yields supersonic metastable atom pulses, with velocity distributions having a relative width as low as 3.8% for helium and 6.5% for argon ( FWHM ) with a 100% modulation of the metastable beams. These features make the source applicable for velocity analyzed scattering experiments using the time-of-flight technique.
- Research Organization:
- Research Institute for Scientific Measurements, Tohoku University, 1-1 Katahira-Nichome, Sendai 980, Japan
- OSTI ID:
- 5139535
- Journal Information:
- Rev. Sci. Instrum.; (United States), Journal Name: Rev. Sci. Instrum.; (United States) Vol. 57:12; ISSN RSINA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
Molecular & Chemical Physics-- Beams & their Reactions
640304 -- Atomic
Molecular & Chemical Physics-- Collision Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
74 ATOMIC AND MOLECULAR PHYSICS
ARGON
ATOM COLLISIONS
ATOMIC BEAMS
BEAMS
COLLISIONS
ELECTRICAL PUMPING
ELECTRON BEAM PUMPING
ELECTRON COLLISIONS
ELECTRON GUNS
ELECTRON-ATOM COLLISIONS
ELEMENTS
ENERGY LEVELS
EXCITED STATES
FLUIDS
GASES
HELIUM
ION SOURCES
METASTABLE STATES
NONMETALS
OPERATION
PULSE TECHNIQUES
PUMPING
RARE GASES
TIME-OF-FLIGHT METHOD