Alpha scintillation

The deposits on the stainless-steel collection plates of the low-pressure impactor (LPI) were leached with a solution of 1 H HNO3 and the leachate rapidly evaporated on 5.08-cm stainless steel plates (using a hot plate). The concentrations of Pb-212 and Pb-214 in the impactor plate leachates were measured using seven ZnS(Ag) alpha scintillation counters. 

Gross alpha and gross beta activity can be determined by various radioactive counters, such as internal proportional, alpha scintillation, and Geiger counters. Radium in water can be measured by co-precipitating with barium sulfate followed by counting alpha particles. Radium-226 can be measured from alpha counting of radon-222. Various methods are well documented (APHA, AWWA, and WEF 1998. Standard Methods for the Examination of Water and Wastewater, 20 ed. Washington DC American Public Health Association). 

Radioactivity of uranium can be measured by alpha counters. The metal is digested in nitric acid. Alpha activity is measured by a counting instrument, such as an alpha scintillation counter or gas-flow proportional counter. Uranium may be separated from the other radioactive substances by radiochemical methods. The metal or its compound(s) is first dissolved. Uranium is coprecipitated with ferric hydroxide. Precipitate is dissolved in an acid and the solution passed through an anion exchange column. Uranium is eluted with dilute hydrochloric acid. The solution is evaporated to near dryness. Uranium is converted to its nitrate and alpha activity is counted. Alternatively, uranium is separated and electrodeposited onto a stainless steel disk and alpha particles counted by alpha pulse height analysis using a silicon surface barrier detector, a semiconductor particle-type detector. 

Elemental composition U 88.15%, O 11.85%. The compound is digested in nitric acid and alpha activity is measured by a gas-flow proportional counter, alpha scintillation counter or other counting instrument. 

Lucas, H.F. (1957) Improved low-level alpha-scintillation counts for radon. Review of Scientific Instruments, 28, 680-3. 

Details of the analytical techniques used to determine the activities of the radionuclides employed are given by Turekian et al. (1973). Briefly, 5 gm samples of peat ash were leached in hot 6 N HCl and the leachate analyzed for Ra and Pb. Radium-226 was determined by recovery of Rn gas produced by decay of parent Ra in solution within a closed vessel for at least ten days, followed by alpha scintillation counting of the separated radon. The procedure was repeated at least twice. Blanks, estimated by extraction without sample in the recycle loop, were small relative to sample activity. 

Alpha monitoring Evacuation to prevent inhalation dose resulting from resuspenstion of ground contamination resulting from an accident involving Plutonium dispersal (e.g., nuclear weapon accident). Alpha scintillation or proportional coimters 5 to 10 cm... 

Alpha scintillation is used for the detection of radioactive radon isotopes (Section 13.8.5.1). 

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