Strong Tl--Xe excimer band emission via electron beam initiated discharges in TlI and Xe mixtures
Stable glow discharges have been produced by an electron beam ionizing pulse (20 nsec) in TlI/Xe mixtures having densities of approximately 1--4 x 10/sup 16//cm/sup 3/ of TlI and 10/sup 19/--10/sup 20//cm/sup 3/ of Xe in order to assess their potential as a medium for a high power Tl--Xe excimer laser system. The use of this thallium salt in place of the pure Tl metal enabled the required operating temperature to be lowered from 820 to 440/sup 0/C. These e-beam initiated discharges are the first type conducted in metal vapors at these high operating temperatures. The electron beam preionized discharges (60 cm/sup 3/) produced a factor of 40 enhancement in the Tl--Xe band emission relative to the pure electron beam pumping. Peak power loadings of 3 kW/cm/sup 3/ were attained for approximately 600 nsec at 2 A/cm/sup 2/ current densitites for E/N values up to 3 x 10/sup -17/ Vx cm/sup 2/. Higher peak power loadings (31 kW/cm/sup 3/) were achieved for shorter pulsewidths without the onset of glow-to-arc transitions. Very strong emission was observed from only the Tl atomic lines and the Tl--Xe bands centered at approximately 6000, 4300, and 3650 A. No emission from excited TlI was ever observed. Monitoring the discharge current gave a TlI attachment rate constant of 1.8 x 10/sup -10/ cm/sup 3/ sec/sup -1/ that was very insensitive to the applied E/N. Available kinetic information is used to develop a plausible model for the dominant kinetic processes involved. The possibility of utilizing the close energy resonance of the Tl and I metastable states to produce lasing at 1.315 ..mu.. is discussed. In addition, engineering details of the test cell construction compatible with the required high operating temperatures are presented.
- Research Organization:
- Air Force Weapons Laboratory, Kirtland Air Force Base, New Mexico 87117
- OSTI ID:
- 5503040
- Journal Information:
- J. Chem. Phys.; (United States), Vol. 72:8
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GAS LASERS
GLOW DISCHARGES
THALLIUM IODIDES
EMISSION SPECTRA
XENON
BINARY MIXTURES
ELECTRON BEAMS
ENERGY-LEVEL TRANSITIONS
BEAMS
DISPERSIONS
ELECTRIC DISCHARGES
ELEMENTS
HALIDES
HALOGEN COMPOUNDS
IODIDES
IODINE COMPOUNDS
LASERS
LEPTON BEAMS
MIXTURES
NONMETALS
PARTICLE BEAMS
RARE GASES
SPECTRA
THALLIUM COMPOUNDS
420300* - Engineering- Lasers- (-1989)