Table 6.

Summary of filament correction factor calculation

1.	From comparison of mixes 2. 4 and SRM 990  $R_{D\left(\text{corrected}\right)}=0.48115$  $\text{S}.\text{D}.=0.00428$  ${\left({}^{28}{\text{Si/}}^{30}\text{Si}\right)}_{990}=29.74608$
2.	From comparison of mix 5 and SRM 990  $\text{Ratio}\frac{{\left({}^{28}{\text{Si/}}^{30}\text{Si}\right)}_{990}}{{\left({}^{28}{\text{Si/}}^{30}\text{Si}\right)}_5}=1.002512$  $\text{S}.\text{D}.=0.00260$  $\text{True}{\left({}^{28}{\text{Si/}}^{30}\text{Si}\right)}_{990}=29.74031$
3.	Average true value = 29.74320
4.	$\text{Correction\hspace{0.17em}factor}=\frac{29.74320}{29.71099}=1.001084$
5.	Correction factor/mass unit = 1.000542
6.	True (29Si/30Si)990 = 1.50598