Discrimination ratios, definition

As there are few data on the ratio of thoron concentration to radon, we have assumed that the value is constant and is equal to 0.14, Error(4) and Error(5) are assumed to be negligible for the error calculation. The error due to ambiguities in classification and discrimination of tracks according to the shape or the size was assessed by experiment and the relative error (1 S.D.) was less than 10%. The relative error due to the variations of F, f, and (V a) is less than 13% as described in the previous section. The combined error due to these factors is estimated to be 16%. The total error can be obtained by combining this error and Error(l). If we use the definition that the lowest detectable limit is the radon concentration at 50 % relative S.D., the lowest detectable... 

True values are unknowable by definition (see Section 6.2) and therefore require a replacement for practical work. The value which is closest to the true isotope amount ratio is the certified isotope amount ratio of an IRM, which in turn means that any correction for mass discrimination requires an IRM with known isotopic composition. With the ion current ratio and the certified isotope amount ratio of the IRM, Rcert,i, the fC-factor can be calculated according to Eq. (6.4) ... 

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