Spark chamber gases

Spark chamber gases. Generally, a mixture of 70 percent to 95 percent neon in helium is used in spark chambers. 

Reviews of spark chambers and thek uses have been previously published (6,7). Essentially, the spark chamber consists of electrodes contained in a chamber filled with an ionizable gas, a mixture of argon containing 10% methane, and this gives a high sensitivity to P radiation. The gas is ionized by radioactive emissions, and these emissions are recorded on film with a camera. The Polaroid film integrates the individual flashes produced over a suitable exposure period. Due to the intensity of the sparks, the film is rapidly saturated, leading to blackening of the film, and hence direct quantitation is not possible. 

Flame plating (D-gun) employs oxygen and fuel gas. In this method, developed by the Union Carbide Corporation, the gas mixture is detonated by an electric spark at four detonations per second. The powders, mixed with the gas, are fed under control into a chamber from which they are ejected when detonation occurs. The molten, 14—16-pm particles are sprayed at a velocity of 732 m/s at distances of 5.1—10.2 cm from the surface. The substrate is moved past the stationary gun. 

In fact, the clearly posed problem of the final state of an unstable laminar flame is a limiting case of turbulent flame for vanishing initial turbulence of the oncoming flow, but the general case, for any initial velocity fluctuations, is clearly of great interest in practical devices such as spark-ignited engines, turbojet, or gas turbine combustion chambers. 

A combustion process which is initiated solely by a timed spark and in which the flame front moves completely across the combustion chamber in a uniform manner at a normal velocity. In such a process there is no sudden release of energy from the fuel-air mixture, nor are there any auxiliary sources of ignition from combustion-chamber deposits, hot spark plugs, overheated valves, or other hot surfaces within the combustion chamber. Engine roughness associated with high gas loads and mechanical deflections of engine a components can accompany normal combustion. 

The basic test apparatus consists of a chamber into which a known concentration of vapor (gas) in air is introduced. After thorough mixing, ignition is attempted with a spark or a hot wire. A series of different concentrations are tested to establish the upper and lower concentration limits for flammability. Although normally run with fuel-air mixtures at ambient conditions, other oxidizing atmospheres, diluent effects and temperature and pressure variations can be studied. 

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