Sampling source monitoring

Figure 10.7 shows a nanosecond kinetic flash photolysis apparatus. The absorbance of the sample is monitored, using a photomultiplier, by the change in the transmittance of the sample to the xenon arc lamp continuous light source. 

The need to prepare very thin sample sources for counting necessitates a lengthy radiochemical separation procedure to remove bulk elements efficiently, as well as alpha emitters that will interfere with the spectra (Table 1). Radiochemical procedures and sample mounting onto a planchet are variable in efficiency and can be affected by sample-related factors. It is therefore imperative to use a yield monitor for the procedure if quantitation is required. After radiochemical separation the solution is prepared for alpha counting using electrodeposition, co-precipitation and filtration as a thin source, direct evaporation, electrospraying, or vacuum sublimation. If the planchet is contaminated with polonium, the planchet is heated to remove the volatile polonium. 

When environmental monitoring is carried out to assess the impact of a particular practice or source, it is referred to as source related environmental monitoring. A source related environmental monitoring programme should be such as to enable the verification of the results of source monitoring by means of samples taken from and measurements made in carefully chosen locations in the vicinity of the facility, selected in view of their correlation with different discharges or accidental releases. It should also enable the assessment of the doses due to external exposure of members of the pubhc outside the boundary of the facility. 

The regulatory requirements relating to source monitoring, environmental monitoring and individual monitoring are met Appropriate methods of sampling and measurement are used ... 

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