Annexes



I. RMS and F_ratio calculation

 

Definitions
x value (in cm-1) represents specific absorbance of the dosimeter :

x = (Abs-BGD) / t

y value (in kGy) represents the real dose absorbed by the dosimeter given by a laboratory connected with the national standard. (SSDL) or by a calorimeter.

(x1,y1), (x2,y2), ……. (xi,yi), ……. (xn,yn) n data points (i=1 to n)

Polynomial fit C0, C1, C2, C3, C4, C5 are determined


II. Dose calculation for each point

 

f (x1), f(x2), ……. f(xi), …….. f(xn)
where : f(xi) = C5.xi5 + C4.xi4 + C3.xi3 + C2.xi2 + C1.xi + C0

RMS and F_ratio calculation

Let :

(residuals)

(mean of real dose)







then :





III. Uncertainty determination of the absorbed dose
 

The absorbed dose uncertainty is calculated according to the Guide for selection and calibration of dosimetry systems for radiation processing. ISO/ASTM DIS 51251 and the Guide to the Expression of Uncertainty in Measurement. 1993, ISBN 92-67-10188-9.

Organization chart from the various uncertainty sources :



1. Uncertainty of the response of a dosimeter

k value (in cm-1) represents specific absorbance of the dosimeter :



Corresponding uncertainty uc(k) :



Where :



2. Uncertainty resulting from the calibration (uc(Cal))




Where :

  • u(Dref) is given by the SDL (Standard Dosimetry Lab.) or Secondary Standard Dosimetry Lab.
  • RMS is calculated just in the previous paragraph and displayed under the calibration coefficients. It represent the uncertainty resulting from the calibration curve fit
  • uc(kcal) is the uncertainty from the response of a reference dosimeter


3. Uncertainty of the calculated dose (uc(D))




The final uncertainty (U(D)) is given in kGy with a coefficient of release k=2.