Fill gas

In these gas-flow proportional counters, the windows are exceedingly thin, fragile,. and unavoidably leaky. Such a window is satisfactory only if a steady flow of. the filling gas is maintained at minimum pressure differential against the helium atmosphere in the optical path. The purging of impurities from the counter is an incidental benefit derived from the gas flow. Hendee, Fine, and Brown20 look upon the gas-flow proportional counter as a steppingstone on the road toward a windowless counter. 

Dosimetry. Ion current measurements required for absolute dosimetry were performed with a Cary 31 ionization chamber and vibrating reed electrometer. Dry nitrogen was used as filling gas for the chamber, and a W value of 34.9 e.v./ion pair was assumed for H-3 beta rays in N2 (27). Deuterium pressures in each of the reaction mixtures were great enough to ensure that less than 1% of the H-3 beta rays reached the walls of the reaction vessel (7). 

To a limited degree, the fill-gas will determine what type of radiation the proportional counter will be able to detect. Argon and helium are the most frequently used fill gases and allow for the detection of alpha, beta, and gamma radiation. When detection of neutrons is necessary, the detectors are usually filled with boron-triflouride gas. 

Filling material (filling gas) Excited species Main emission bands, X (nm) References... 

The filling gas pressure of a CVGT must be carefully chosen it must be high enough to get a good sensitivity and low enough to approximate the ideal gas behaviour. 

Stephens RD, Ball ND, Mar DM. 1986. A multimedia study of hazardous waste land fill gas migration. In Pollutants in a Multimedia Environment. New York, NY Plenum Press, 265-287. 

Dissolve 175 g of KOH in 1,750 ml of water in a flask of 5 liters volume equipped with a reflux condenser and a gas inlet tube. If a stirring device is not required, it should be removed and the open neck stoppered. Heat the mixture to 80° under a stream of nitrogen and add 500 g of ergotamine tartrate. Hold the temp at 80° for 2Vi hours with bubbling from the nitrogen filled gas inlet tube. Pour the mixture into a 5 gallon polyethylene bucket (made from the same... 

Immediately after ignition, mercury is still liquid and the discharge takes place in the fill gas (argon). At this point the voltage is low and the current is limited essentially by the short-circuit current delivered by the power supply. As the temperature within the lamp increases, mercury vaporizes. The lamp impedance increases, and this causes the lamp voltage to increase and the current to decrease. After about 1 min, the bum-in period is finished and the lamp reaches stationary conditions. 

Mercury thermometers are subject to separation of the mercury column or to inclusion of bubbles of the fill gas. These may result from shipping and handling and cause a scale offset which can usually be seen upon visual examination, and they are always recognized by a 0°C verification check. Manufacturers will suggest means by which these temporary defects may be cured. 

Preparation of Sulphuric Acid by the Contact Process. Assemble an apparatus as shown in Fig. 72. Fill gas meter 1 with oxygen and... 

The spectrum emitted by the lamp corresponds to the radiation emitted by the cathode superimposed on that emitted by the filling gas. The width of the emission... 

Apply a water-filled gas trap after the ozone destructor. This makes it easy to visually control the gas-flow or detect leaks. It furthermore smoothes the gas-flow, due to the back pressure of the liquid (height). ... 

Gas filling apparatus used to fill gas component into the cylinder, which consists of the following parts ... 

Note These data were taken from an Ar-filled Ga HCL at the Los Alamos Fourier Transform Spectrometer facility.11... 

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