Showing papers on "Buffer gas published in 1971"

Infrared Lasers Resulting from Giant Pulse Laser Excitation of Alkali Metal Molecules

Abstract: Infrared laser action is observed to occur in vapors of K, Rb, and Cs photoexcited by various giant pulse laser beams. The mechanism of excitation involves two‐photon absorption by the molecular species followed by dissociation into various excited atomic states. In the case of cesium, anomalously long infrared laser pulses are obtained when helium buffer gas is present. A collisional mechanism is invoked to explain this phenomenon. Self‐focusing of a ruby laser beam is also observed to occur in cesium–helium vapor under certain conditions.

Incorpation of Helium in Deposited Gold Films

Abstract: It is shown that sputter deposited gold films containing atomic ratios of helium-to-gold of up to 0.4 may be formed in a helium gas dc diode discharge. Gas content is primarily a function of substrate temperature and bias, gas pressure, and target voltage. Data indicate that high-energy neutral helium atoms originating at the target are important in the gas incorporation at low gas pressures and positive substrate biases. Maximum helium incorporation occurs at about −80 V bias, where the sticking coefficient is expected to approach unity. Deposition conditions are influential in the subsequent thermal release of the incorporated gas. Gas analysis was performed by heating and flash evaporation of the gas-containing film and then determining the pressure rise in a known volume. It is proposed that this technique is applicable to the formation of many nonequilibrium gas–metal/ceramic systems.

Sunlight photodetachment of O3

Abstract: The rate of photodetachment of O3− by sunlight has been determined. The O3− ions were identified by their mobility as they drifted in a weak field in 1 torr of O2 buffer gas. This allowed the ions to lose any vibrational or electronic excitation through collisions with the buffer gas. Energy dependence of the cross section was estimated by the use of colored filters in the photon beam. The sunlight photodetachment rate measured was 0.2± 0.1 sec−1.

Spectral absorption coefficients of helium and neon buffer gases and nitric oxide-oxygen seed gas mixture

Abstract: Spectral absorption coefficients of helium, neon, and nitric oxide mixtures with oxygen as functions of pressure, temperature, and wave number

Inert gas recovery from synthesis products

Abstract: He and/or A, opt. mixed with other inert gases, e.g. Ne, are recovered by subjecting gas mixture containing these gases to synthesis, recycling unchanged fraction and separating synthesis product from cycle by condensation. Inert gases dissolved in liquid synthesis product are expelled from this and mixed with either cycle gas or partial stream of exhaust gas stream enriched in inert gas. Process is esp. suitable for recovering A from air used in NH3, synthesis or He from natural gas used for H2 manufacture. Concentration of inert gas in mixture facilitates recovery by reducing vol. of gas to be processed.

Radiation heat transfer calculations for the uranium fuel-containment region of the nuclear light bulb engine.

Abstract: Calculation results are reviewed of the radiant heat transfer characteristics in the fuel and buffer gas regions of a nuclear light bulb engine based on the transfer of energy by thermal radiation from gaseous uranium fuel in a neon vortex, through an internally cooled transparent wall, to seeded hydrogen propellant. The results indicate that the fraction of UV energy incident on the transparent walls increases with increasing power level. For the reference engine power level of 4600 megw, it is necessary to employ space radiators to reject the UV radiated energy absorbed by the transparent walls. This UV energy can be blocked by employing nitric oxide and oxygen seed gases in the fuel and buffer gas regions. However, this results in increased UV absorption in the buffer gas which also requires space radiators to reject the heat load.

Kinetic Processes in Noble Gas Ion Lasers.

Abstract: : A quantitative theory is proposed for calculation of the state of the plasma and various electronic excitation rates in high-current low pressure discharges typical of noble gas ion laser operation under quasi-steady state, constant-pressure or constant-density conditions. At present, only wall-confined discharges in the absence of any externally applied magnetic fields is considered. For simplicity, multiple ionization is also neglected. The discharge is formulated as a three-temperature problem with significant axial electron drift. It is found that the natural similarity parameters in such a discharge are pR(the product of the total filling gas pressure p and the discharge tube radius R), and jR (the product of current density j and the tube radius). (Author)