Surface discharge UV arc sources for laser excitations. Final report

Technical Report · Thu Jun 10 00:00:00 EDT 1976

OSTI ID:7324474

Beverly, III, R E; Barnes, R H; Moeller, C E; Wong, M C

High-current surface-spark discharges were spectroscopically investigated as intense sources of soft-UV radiation for laser excitation. Particular emphasis was placed on the nominal pumpband of the iodine photodissociation laser (2500 to 2900 A), and absolute measurements of the radiated energies, energy densities, and electrical-to-optical conversion efficiencies under different experimental conditions were performed. Time-integrated and time-resolved spectroscopic techniques were employed with Al/sub 2/O/sub 3/- and BN-substrate sources having stainless steel electrodes separated by 1- to 10-mm gaps and immersed in high-pressure (1 to 10 atm) Ar, He, N/sub 2/, SF/sub 6/, and CO/sub 2/ pure gases and typical highly-pressure-broadened iodine amplifier gas mixtures, e.g., Ar + i-C/sub 3/F/sub 7/I. Circuit parameters were such that 1 to 20 J of electrical energy was dissipated by the plasma channel for an oscillatory discharge with ring frequency of about 1 MHz and circuit strengths of 0.2 to 4 x 10/sup 10/ Volts/Henry. Highly-conservative absolute measurements indicate a 4.3 percent conversion efficiency in the iodine pumpband for pure Ar at 10 atm pressure. The addition of a complex perfluoroalkyl iodide to the pure diluent does not degrade the source performance, and energy densities approximately 1 J/cm/sup 2/ are readily attainable. Principal advantages of the surface-spark source for laser excitation are a compatibility with desirable gas mixtures and pressures, good conversion efficiencies and large energy densities, the feasibility of large densely-packed multiple arrays, and the excellent reliability, long-life expectancy, and inexpensive nature of the structures. Spectral enhancement in the soft-UV regions appears promising by careful selection of doped ceramic substrates having constituents which radiate strongly via line emission when vaporized. The use of tungsten electrodes with longer surface gaps and faster discharge circuitry may also afford improvements in performance.

• Research Organization: Battelle Columbus Labs., OH (USA)
• DOE Contract Number: W-7405-ENG-92-TAS-81
• OSTI ID: 7324474
• Report Number(s): BMI-X-671
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
GAS LASERS
PUMPING
ALUMINIUM OXIDES
ARGON
BORON NITRIDES
CARBON DIOXIDE
ELECTRIC DISCHARGES
ELECTRIC SPARKS
EXCITATION
HELIUM
IODINE
NITROGEN
PHOTOLYSIS
SURFACES
ULTRAVIOLET RADIATION
ALUMINIUM COMPOUNDS
BORON COMPOUNDS
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
CHEMICAL REACTIONS
CRYOGENIC FLUIDS
DECOMPOSITION
ELECTROMAGNETIC RADIATION
ELEMENTS
ENERGY-LEVEL TRANSITIONS
FLUIDS
HALOGENS
LASERS
NITRIDES
NITROGEN COMPOUNDS
NONMETALS
OXIDES
OXYGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PNICTIDES
RADIATIONS
RARE GASES
420300* - Engineering- Lasers- (-1989)