Magnesium sulfide activated with europium and samarium is a candidate phosphor for laser stimulated personnel dosimeters. Optically stimulated luminescence (OSL) dosimeters are advantageous in that they provide a faster, isothermal dose measurement than conventional thermoluminescent dosimeters. The effects of activator concentration and chemical substituents are examined in order to increase OSL intensity, improve the OSL emission wavelength and to increase the chemical stability of the MgS lattice. In addition, UV photoluminescence and thermoluminescence of the MgS:Eu:Sm phosphor was investigated to improve the understanding of the optical processes in MgS:Eu:Sm phosphors. / Master of Science