Gaseous Scintillators

Allow the samples and blanks to precipitate for about 15 min at room temperature and centrifuge for 5-10 min at 2000 xg. Decant the supernatant carefully and resuspend the pellet in 3 ml ethanol (66%), then centrifuge for 5-10 min at 2000 xg. Resuspend the pellet in 2.5 ml acetone then centrifuge for 10 min at 2000 xg. Decant the supernatant carefully and dry the pellet in a vacuum or under gaseous nitrogen. Dissolve the pellet in 0.5 ml H20 and add it to 10 ml scintillation liquid in counter vials. Rinse the centrifugation tube twice with 0.5 ml H20 each and add to the sample in the scintillation liquid. 

The content of tritium is usually determined by measuring its activity. Solid samples may be converted into liqnid or gaseous compounds, and the tritium content measured by a liquid scintillation counter or a gas proportional counter, respectively. 

These properties make the gaseous scintillators suitable for the energy measurement of heavy charged particles (alphas, fission fragments, other heavy ions). 

The release point for the HCF ventilation system exhaust is the HCF exhaust stack. Gaseous effluent discharged in the ventilation system is continuously monitored. The monitor electronically records selected beta-gamma emitting radionuclides as well as noble gases. The system is calibrated and maintained by representatives of the SNL ES H Center and is discussed in Chapter 7. Liquid effluent from the LECS is sampled prior to release into the sanitary system. The samples are analyzed by gamma spectroscopy and liquid scintillation. No discharges to the sanitary system are allowed until analyses show that levels are within the established release limits.. ... 

It has been established that this is due to loss of gaseous C02 (Herbland, 1977). On the other hand unstable and dropping count rates resulted when the NaOH concentration exceeded a certain amount (5 mg NaOH/10 ml scintillation fluid in most cases). This was evidently due to the NaOH exhibiting the well known property of electrolytes in destroying, or "breaking", emulsions. 

In the lamp industry, the three gases serve as fill gas in specialty lamps, neon glow lamps, 100-watt fluorescent lamps, ultraviolet sterilizing lamps, and very high-output lamps. The three gases have additional applications in the atomic energy field as fill gas for ionization chambers, bubble chambers, gaseous scintillation counters, and other detection and measurement devices. 

Alpha particles may be counted also by gaseous, liquid, plastic, and crystalline scintillation detectors. The resolution of these detectors is. In general, less, than Ionization chambers and their application more limited. Nuclear emulsions are used to record alpha activity. Such devices as cloud chambers are generally not used In the radloehemlatry laboratory. 

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