Figure 2.

${\mathrm{f}}_{\text{MV}}(\mathrm{d},\mathrm{L})$ factors obtained for $4\times 4$ (□), $10\times 10$ (⋄), $16\times 16$ (Δ) and $20\times 20\hspace{0.17em}{\text{cm}}^2$ square (O) fields of 15 MV, and the linear fit (continuous lines) by Eq. (13).