Footprint curves in the plane of the IP, folded out to be flat. Different curves represent different scattering angles in radians. The full line (blue) is the numerical calculation and red dots represent the circular approximation. The curves are at 0.1, 0.2, 0.5 and 1 rad. When the opening angle of the cone approaches π the footprint approaches a straight line. The IP strip in the present case is shown in green (the width of the IP is 13 mm and the radius R of the camera is 300 mm).