Buffer gas

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

Velocity distribution of mass-selected nano-size cluster ions

Abstract: The paper reports on an experimental investigation of the ion velocity distribution function (IVDF) for mass-selected copper cluster ions with a diameter in the range 5–10 nm. The cluster ion beam is produced by a dc magnetron-based gas aggregation source. The measurements are carried out by means of a quadrupole mass filter combined with a basic retarding field analyser. The most probable cluster velocities are in the range 80–180 m s−1; decreasing with cluster size and increasing with buffer gas (Ar) flow. Experimental results are compared with the theoretical model of Smirnov et al. Noted discrepancies are explained by the interaction of clusters with buffer gas atoms outside the aggregation chamber during the passage from the orifice towards the detector. This interaction is not included in the theoretical model. Both positively and negatively charged clusters are investigated. The density ratio of positively to negatively charged clusters in the beam is evaluated from the measured IVDFs and compared with the theoretical model.

Superpurifier for argon gas and process for purifying argon gas

Abstract: The present invention relates to a superpurifier for argon gas and to a process for superpurifying an argon gas According to the invention, the superpurifier comprises means for contacting an impurity-containing argon gas with a getter material which is an alloy of zirconium, vanadium and iron The getter material of the superpurifier selectively sorbs impurities from an impurity-containing argon gas thereby producing a purified argon gas The present invention also relates to a method of purifying an impurity-containing argon gas using this superpurifier The present invention provides means for obtaining an argon gas of higher purity than can be obtained by prior purifying processes and apparatus

High resolution `VUV laser' measurements of the band oscillator strengths of the CO transition

Abstract: Band-integrated oscillator strengths of the transition for have been measured in absorption using a high-resolution tunable VUV coherent light source (`VUV laser') as a background source. The rotationally resolved absorption spectra are least-squares fitted by precise synthetic spectra in order to take into account the instrumental saturation effects. The fitting parameters are the oscillator strength, the rotational line width and the instrumental width. Saturation effects are reduced by pressure broadening the absorption lines using up to 1.5 bar of argon as a buffer gas. The new data set extends the range covered by recent measurements to . Cross sections for are measured here for the first time. The present results are in general agreement with the latest measurements and with ab initio calculations. The average broadening coefficient of the CO rotational lines by argon is determined in this study for the first time: . The variation of with and J is small and could not be measured in the present experiments.

Correlation function of spin noise due to atomic diffusion

Abstract: We use paramagnetic Faraday rotation to study spin noise spectrum from unpolarized Rb vapor in a tightly focused probe beam in the presence of ${\mathrm{N}}_{2}$ buffer gas. We derive an analytical form for the diffusion component of the spin noise time-correlation function in a Gaussian probe beam. We also obtain analytical forms for the frequency spectrum of the spin noise in the limit of a tightly focused or a collimated Gaussian beam in the presence of diffusion. In particular, we find that in a tightly focused probe beam the spectral line shape can be independent of the buffer gas pressure. Experimentally, we find good agreement between the calculated and the measured spin noise spectra for ${\mathrm{N}}_{2}$ gas pressures ranging from 56 to 820 Torr.

Observation of Ramsey fringes in an atomic cell with buffer gas.

Abstract: Temporal Ramsey fringes that are due to light scattering by coherently prepared rubidium atoms diffusing through a cell containing neon as a buffer gas have been observed. The effect leads to increasing magneto-optical rotation of cw light polarization at weak magnetic fields.