Spectrotabs have a much lower level of impurities. Spectrotabs, pack of 120. These discs are highly recommended for routine use, being coated with a very uniform layer of carefully selected P47 phosphor. They have a high signal output and a good working life. They should not normally be coated with aluminum, unless cathodoluminescence studies are envisaged.
Discs are available for all principle types of microscope.
They are therefore particularly suited for high current operations. Light emission peaks at about 560nm which means that S20 photo cathodes are most suitable for detecting the emission. The response is better than for the Plano 47 discs below 5kV and again at higher accelerating voltages, where the performance of powder scintillators falls off while the response of the YAG continues to increase linearly. The crystal should be coated with 50nm of aluminum before use. If the layer becomes damaged, it can be removed with sodium hydroxide without damage to the crystal.