The dimension of detector is 12x12x12 mm3. Applied 1 V in z=12 plane at 5.5 Here is the weighting potential in density plot, equipotential line (green), and electric field vectors (black). It is weight potential in pixellated detector along z-axis at x = 6 mm and y = 6 mm. The shape of weighting potential is same with that of Frisch-grid and hemi-spherical detector. Now you can understand ..
