Add the contribution of $\Psi_A$ in the mask region to the photo-electron spectrum. Literally adds the Fourier components of: $\Theta(r-R1) \Psi_A(r)$ with $\Theta$ being the Heaviside step function. With this option PES will contain all the contributions starting from the inner radius $R1$. Use this option to improve convergence with respect to the box size and total simulation time. Note: Carefully choose $R1$ in order to avoid contributions from returning electrons.