DESIGN AND CHARACTERIZATION OF A SINGLE-REFLECTION, SOLID-STATE DETECTOR WITH HIGH DISCRIMINATION AGAINST BACKSCATTERED ELECTRONS FOR CATHODOLUMINESCENCE-MICROSCOPY

A portable solid-state detector (SSD) for cathodoluminescence (CL) has been constructed and tested. The detector geometry utilises a parabol ic, reflector to direct light towards the solid-state detection elemen t. The photo-sensitive area of the solid-state photodiodes is situated at a level in line with or sightly below the top surface of the speci men to minimise the collection of backscattered electrons (BSEs) comin g directly from the beam impact point. The components have been integr ated into a single unit to enhance portability. In comparison with a c ommercial CL detection system, the new geometry shows excellent effici ency in rejecting BSE contribution during CL operation. A light collec tion solid angle close to 1.97 pi steradian is realised in this geomet ry, higher than other SSD-CL systems. A method for characterising CL d etection system performance has been developed.