GENERALIZATION OF THE VARIANCE COVARIANCE METHOD FOR MICRODOSIMETRIC MEASUREMENTS .3. NUMERICAL-SIMULATION TO ASSESS THE APPLICABILITY OF THE FORMULAS

Numerical simulations in terms of microdosimetric data for 5-MeV neutr ons are utilized to test the twin detector method of microdosimetric m easurements in its new, extended form. Three different conditions of m easurement are considered, (I) constant dose increments per measuremen t, (II) fluctuating dose increments per measurement, and (III) fluctua ting does increments combined with slow changes of the dose-rate ratio for the two detectors. Under each of the conditions, large numbers of measurement series are simulated, and the estimation formulae for the mean and the two subsequent moments of the dose-weighted single-event distribution, d(y), are applied. The estimation formulae exist in thr ee different forms: uncorrected formulae that apply to condition I, co rrected formulae that are valid also for condition II, and fully corre cted formulae that remain applicable under condition III. The results of the simulations indicate the acceptable ranges of doses per measure ment interval. It can be seen that all three parameters are obtainable through the twin detector method, and that the fully corrected formul ae for the two lower moments are generally applicable. The determinati on of the third moment is possible only under limited conditions, and the fully corrected formula is not useful in this case, while the corr ected formula has some applicability even under condition III.