Functional Polymeric Coatings for CsI(Tl) Scintillators

The handling of inorganic scintillators (e.g., alkali metal halides) can benefit from the availability of polymeric materials able to adhere to their surface. Polymeric materials, such as epoxy resins, can act as protective coatings, as adhesives for photodiodes to be connected with the scintillator surface, and as a matrix for functional fillers to improve the optical properties of scintillators. Here, the optical properties of two epoxy resins (E-30 by Prochima, and Technovit Epox by Heraeus Kulzer) deposited on the surface of a scintillator crystal made of CsI(Tl) were investigated, in order to improve the detection of high-energy radiation. It is found that these resins are capable of adhering to the surface of alkali metal halides. Adhesion, active at the epoxy–CsI(Tl) interface, can be explained on the basis of Coulomb forces acting between the ionic solid surface and an ionic intermediate of synthesis generated during the epoxy setting reaction. Technovit Epox showed higher transparency, and it was also functionalized by embedding white powdered pigments (PTFE or BaSO4) to achieve an optically reflective coating on the scintillator surface.