Substrates for suspending sample elements are disclosed, as well as sample platforms comprising such substrates, in which the sample elements can be analyzed with improved reliability. In exemplary embodiments, such sample elements are used in thermoluminescence dosimeters (TLDs) or optically stimulated luminescence dosimeters (OSLDs) to provide a calculated radiation dose with improved accuracy. The reproducibility associated with analyzing a sample element, and particularly one suspended by a film or encapsulated within films, may be significantly improved by tensioning the film(s). Tensioning may result during assembly of a sample platform, using a mechanical creasing force that is applied as the result of the configuration of a substrate of the sample platform, such as opposing sections or plates of this substrate. Alternatively, tensioning may be achieved using a separate application of force to the film(s) against a section or plate of the substrate.