Thermoluminescent Properties of Calcite

The effects on thermoluminescent properties of adding certain impurities to calcite have been investigated. The impurities were added as coprecipitants and their concentrations in the solid were determined by colorimetric techniques. Each of the ions which ordinarily function as activators was added but only Mn⁺⁺ and Pb⁺⁺ were found to be activators in calcite. Mn⁺⁺ is responsible for two prominent peaks in the glow curve at 350 and 470°K which coincide with two of the three prominent peaks commonly found in natural samples. Pb⁺⁺ produces two peaks of lower intensity at 300 and 410°K. Fe⁺⁺⁺, Co⁺⁺, and Ni⁺⁺ quench the Mn⁺⁺ and Pb⁺⁺ luminescence and Co⁺⁺ or Ni⁺⁺ in the presence of Mn⁺⁺ results in a 600°K peak in the glow curve which coincides with the third peak generally found in natural samples. The results for efficiency of luminescence as a function of activator concentration for the Mn⁺⁺, Pb⁺⁺, and Mn-Co and Mn-Ni glow peaks are presented and discussed.