Cathodoluminescence of Some Synthetic Calcite Crystals. Investigation on the Role Played by Cerium

Cathodoluminescence (CL) from undoped and cerium-doped synthetic calcite is examined at room temperature and at liquid nitrogen temperature, using a scanning electron microscope. At room temperature, all of the samples exhibit a CL emission in the near ultra-violet (UV), centered at approximately 370 nm with some possible shoulders at 345 nm. At low temperature, the samples show an emission of CL in the near UV but with two well defined maxima for the Ce-doped crystals (460 ppm and 4600 ppm) peaking at 345 and around 380 nm. The third Ce-doped crystal (1.74%) presents a maximum at 375 nm and a shoulder at 345 nm. The undoped crystal shows a maximum at 370 nm and a shoulder at 345 nm similar to the others. In this case, inductively coupled plasma mass spectrometry (ICP-MS) measurements have been carried out to determine the eventual presence of cerium: 1 ppm was detected (other elements such as iron, manganese and lanthanum were also detected). Thus, the near UV emission bands are interpreted as due to the presence of Ce3+ substituting at calcium sites as already shown in the literature using photoluminescence results. Other emission bands have been detected in the rest of the spectrum for which some bibliographical data or some hypotheses are given. This work is dedicated to further applications in cathodoluminescence interpretation of archaeological marble. One example is described