Thermo- and cathodoluminescence properties of Sepiolite

Full text: Sepiolite, Si₁₂Mg₈O₃₀(OH)₄(OH₂)₄·8H₂O, has been well studied from the chemical and structural point of view; however, studies on their luminescence properties have been scarcely reported. This work focuses on the thermoluminescence (Tl) and cathodoluminescence (Cl) response of a natural sepiolite from Madrid, Spain previously characterized by means of environmental scanning electron microscope, X-ray fluorescence (X RF) and X-ray diffraction (XRD) techniques. The complexity of the thermoluminescence glow curves of non-irradiated and irradiated samples suggests a structure of a continuous trap distribution involving multi-order kinetics. UV-IR Cl spectral emission shows five peaks centered at 330, 400, 440, 520 and 770 nm. Such emission bands could be due to (i) structural defects, [AlO₄] or non bridging oxygen hole centers, and (II) the presence of point defects associated with Mn²⁺ and Fe³⁺. Sepiolite, which has different household applications such as: moisture control, containment of accidental liquid spillages, in ashtrays to avoid smoke odor, control of liquid leakages, and odours in dustbins and cat litters; is a good candidate for personal dosimetry in the case of radiation accident or radiological terrorism. in situations where knowledge of doses to individuals is required, but monitoring was not planned. (Author)