As more elements are added to an array of sensors, the total area occupied by the array increases. At close working distances, the outer sensors present a poor geometry to the beam-spot. Entry angles can be large and shadowing may occur from window mounts and on-chip collimators.
To counter these problems, RaySpec developed the ‘focused array’ whereby each sensor is mounted such that its plane lies tangential to a sphere of radius equal to the optimum source distance.
In this design each sensor has optimum geometry with x-rays entering along the axis and all subtend the same solid angle at the target. Although there is one optimised source position (focus), the detector may be used over a wide range of working distances with the geometry remaining improved compared to a planar array.