Krypton Concentration Research Articles

Geothermal tracing with atmospheric and radiogenic noble gases

Meteoric water is tagged by its dissolved atmospheric neon, argon, krypton and xenon concentrations and isotopic compositions. These gases are kept in the groundwater unless it is subsequently heated in geothermal regions and a steam phase is produced. In such cases the noble gases pass quantitatively into the steam phase and the remaining water becomes depleted. Radiogenic helium, argon and radon enter deep-seated hot waters by flushing from country rocks in which they are formed. The noble gases, being inert, serve as conservative tracers the concentrations and isotopic composition of which provide useful indications of geothermal phenomena. Available information includes: (a) indications of meteoric origin, (b) degree of mixing between shallow water and deep-seated water, (c) previous heating episodes which caused depletion of the noble gas contents in water, (d) the mechanisms by which steam is formed underground (hopefully deducible from the degree and mode of fractionation observed between light and heavy noble gases), (e) interconnections between adjacent producing wells and their optimal spacing in a steam field. Systematic studies on geothermal systems necessitate proper sample collection of water sources over the entire geothermal region and its peripheries, collection from successive water horizons passed while drilling, and repeated sample collections in order to study seasonal and man-induced changes with time.

Krypton Diffusion in Scintillation Counter Plastic

THE determination of radioactive krypton in the atmosphere, as carried out by the Radiological Sciences Laboratory, New York State Department of Health (private communication from N. Irving Sax), involves extraction and concentration of krypton, then injection of this into a vial containing chips of a scintillation counter plastic, such as p-terphenyl in polyvinyltoluene commercially available from Pilot Chemicals, Massachusetts. By scintillation counting, this procedure measures extremely low levels of the β emitter, 10.76 yr krypton-85.

Surface areas and c values for chemically etched and thermally oxidized silicon single-crystal surfaces by Krypton absorption

The chemical and physical nature of the surfaces of chemically polished single-crystal silicon, steam oxidized and dry oxygen oxidized (5000 A) single crystal silicon, and an etched-back oxide were evaluated by measuring the roughness factors and c values using krypton adsorption isotherms reduced by application of the BET equation. Replicate electron micrographs were also made. Steam and dry oxygen oxidized surfaces, though similar in chemical constitution, appeared dissimilar from electron micrographs. Roughness factors differed by a factor of two inversely to structure observed in micrographs. This is explained by a difference in c values thus suggesting that the physical nature of a surface influences the sorbate-sorbent interaction energy. Chemically polished and oxide etch-back silicon surfaces exhibited the same inverse relationship between normalized c values and rf. Unexpectedly high roughness factors are explained on the basis of low monolayer volumes observed for the steam-oxidized surfaces and the chemically polished surfaces.

Rare gases in Pacific Ocean water

Concentrations of helium, neon, argon, krypton, and xenon have been measured in some S. Pacific waters. For the latter four gases the observed concentrations are generally consistent to about ± 10% with concentrations expected for solubility equilibrium with the atmosphere at the observed water temperatures.

Multicomponent diffusion in the system 85Kr-He-Kr

The diffusion coefficients of 85 Kr in trace quantities in mixtures of helium and normal krypton, as well as in pure helium and pure krypton, have been determined by using an all-metal apparatus. The apparatus consists of two diffusion chambers joined by a diffusion capillary of special design so that the chambers can be connected or disconnected by a bellows operated piston valve. For analysis one of the chambers has a thin cellophane window with a scintillation counter placed close to it. First both the chambers were filled with the desired gas mixture and then a small amount of 85 Kr was added to one chamber and the pressures equalized. Diffusion was then started and the counting rate determined at regular intervals, from which the relaxation time and the diffusion coefficient were calculated. The diffusion coefficient D 1→23 of 85 Kr in the mixture of Krypton and helium is found to be accurately given by the theoretically predicted formula: 1 D 1→23 = ( C 2 D 12 )+( C 3 D 13 ) where C 2 C 3 are the concentrations of normal krypton and helium, and D 12 and D 13 are the binary diffusion coefficients. As expected, a plot of the experimental values of 1/ D 1→23 against C 3 is found to be a straight line from which D 12 and D 13 are calculated.

Radio-analysis of krypton and xenon and its use in diffusion experiments with silver

A method has been evaluated which is capable of analyzing relative concentrations of krypton and xenon gases whose total concentration is in the range of 10 −10 to 10 −8 gram atoms. The necessary gas collection and gas-transfer apparatus is described. Krypton-85 and xenon-133 are produced by neutron irradiation and their activities are counted with a gamma spectrometer. The isotopes are identified by the energy of their gamma radiations and by their disintegration half-lives. The use of the radioanalysis technique for the determination of diffusion coefficients of krypton in silver has proven successful. The equipment used in diffusing the gas and in collecting and analyzing the gas samples is described. The values of diffusion coefficients at 500, 600, 700, 735, and 800C are given. These values can be represented by the following equation. D = 1.05 exp (− 35,000/ RT) cm 2/sec Thus, the activation energy for the diffusion of krypton in silver is 35 kcal per gram atom.