Over the years, efficiency of backscattered electron detectors has improved. Robinson has developed a unique system whereby two BSE detectors are used, offering an array of benefits to the SEM operator. The system consists of two detectors with scintillators of dedicated geometrical shape, providing a collection area greater than 2000 mm2. They are situated against the axis of the electron beam, with the right and left signals combining to form the overall image signal - one that is 1.5 times greater than that of a single detector. The omnidirectional image illumination, similar to that attained thorough a traditional SE detector, prevents shadowing due to the 180° collection angle.