Buffer gas

About: Buffer gas is a research topic. Over the lifetime, 3565 publications have been published within this topic receiving 47283 citations.

Diagnostics of water-containing gas mixtures using thermal laser-induced gratings

Abstract: Laser-induced gratings (LIGs) experiments, employing vibrational-overtone excitation of H 2 O molecules through rovibrational transitions of the (2 1 1) ← (0 0 0) band around 820 nm to produce gratings, have been performed in humid ambient air, in a room-temperature cell with neat water vapor or that diluted in buffer gas at pressures of 0.02–4 bar, and in the vicinity of premixed atmospheric pressure CH 4 -air flame, with the aim to investigate the feasibilities of the techniques for accomplishing gas diagnostics or tracing H 2 O at various temperatures and pressures. In highly vibrationally-excited H 2 O rapid multi-stage collisional thermalization processes occur, and as a result both strong oscillatory (due to standing acoustic waves) and stationary (due to stationary density modulations) contributions to LIGs have been observed in gas mixtures. Temporal profiles of LIG signals recorded at various conditions of gas mixtures employed have been analysed in frame of a model of a two- or three-stage R – T , V – V ′, and V – T collisional relaxation of H 2 O and buffer gas molecules. The informative parameters, like adiabatic sound velocity, gas temperature, H 2 O mole fraction have been derived. The results of the analysis are presented, demonstrating possibilities and challenges of the technique in application to gas diagnostics.

Curtain gas filter for mass- and mobility-analyzers that excludes ion-source gases and ions of high mobility

Abstract: A filter for a mass- or mobility-spectrometer that bars gases or vapors of a high-pressure ion source, as well as ions of high mobility and charged droplets, from entering an evacuated mass spectrometer or a mobility spectrometer at a lower pressure than the filter. The buffer gas of the high pressure ion source is blown into the volume of this filter directly or through tubes from where buffer gas and embedded ions are sucked through the aperture of a diaphragm or through an aperture of a capillary mainly from an “extraction volume” filled with a separately supplied clean gas, into which ions of interest are pushed by electric fields formed by electrodes that are substantially rotational symmetric around the “extraction volume” and a substantially flat electrode with respect to an axis of ion extraction and the end of the capillary and the end of a coaxial tube surrounding the capillary.

Recent progress in the development of electrically and optically pumped dye vapor lasers

Abstract: This paper reviews new results in the field of organic dye vapor lasers Gain studies of the scintillator dye POPOP in liquid solution and in the vapor phase show that a dye vapor exhibits optical gain nearly as high as in the solution case under excitation by a N 2 laser Superradiant emission has been observed from both, optically excited POPOP vapor and electron-beam excited vapor The optimum operating conditions of an electron-beam pumped dye vapor-buffer gas system with high purity argon as buffer are reported Potential energy transfer processes from the rare-gas buffer to the dye vapor are discussed The metastable ionic species Ar+ 2 has been identified as the most likely POPOP excitation source after intense electron pumping of the dense Ar buffer gas at typically 4-5 atm An estimate of the conversion efficiency from electronic energy deposited in the Ar buffer to stimulated emission of the dye yields 5 percent These results suggest that an efficient tunable electron beam pumped dye vapor laser is feasible

Nanosecond pulse transmission of buffered SF 6 at 10.6 µm

Abstract: The 10.6 μm transmission properties of SF 6 were measured using nanosecond-duration pulses for various buffer gases and buffer gas pressures up to 3 atm. The addition of a buffer gas strongly increased the SF 6 absorption at moderate energy fluences without significantly altering the high fluence pulse transmission. For pressures above 1 atm, the transmission behavior appeared independent of the pulse duration over the range of parameters investigated in this experiment. The implication of these results for CO 2 laser applications will be discussed.

Micromachined alkali atom vapor cells for chip-scale atomic clocks

Abstract: This paper describes the fabrication of chip-scale alkali atom vapor cells, for use in highly miniaturized atomic frequency references, using silicon micromachining and anodic bonding technology. The cells consist of silicon cavities with internal volume ranging from a few mm/sup 3/ to less than 1 mm/sup 3/. The cells were filled with cesium and nitrogen buffer gas either by chemical reaction of cesium chloride and barium azide, or by direct injection of elemental cesium within a controlled anaerobic environment. Cesium optical absorption spectra were obtained from the cells, and coherent population trapping resonances with linewidths of about 1 kHz were measured.