An improved image-intensifier spectrograph for recording triboluminescent spectra

An image-intensifier spectrograph was designed for recording the weak triboluminescent (TRL) spectra that result from both crushing and diamond saw cutting of samples. The instrument uses a condenser lens for the input optics, and this allows light from a large volume of samples (10*10*70 mm 3 ) to enter the spectrograph. The apparatus was optimised for film output, and uses an f/2 telescope lens in conjunction with a 1800 lines per mm grating to give a higher resolution than previously reported for this type of instrument. Measurements of the TRL spectra of the minerals quartz, fluorite and calcite are presented. The spectrum of calcite is found to originate from traces of samarium.