Fabrication of columnar CsI and CsI:Na scintillation films deposited by vacuum thermal evaporation at high deposition rates

•CsI and CsI:Na scintillation films deposited by thermal evaporation at high rates.•Moisture resistance of film increased by high deposition rate and protective layer.•A clear columnar structure with a single preferred orientation along (200) plane.•Luminescence light of CsI and CsI:Na films generated by UV and X-ray irradiation.•The luminescence signal of CsI film at ∼410 nm enhanced by doping with 1 wt.% NaI.

Alkali halides have been increasingly used as scintillators and sensors in imaging and experimental particle physics applications. The luminescence efficiency of alkali halides is an important aspect of their application in imaging studies and related fields. Therefore, we investigate the optical, scintillation, and hygroscopic properties of cesium iodide (CsI) and sodium-doped CsI (CsI:Na) films grown via vacuum deposition at high deposition rates ∼90 nm/s. The film deposited on a protective layer (such as: SiO2, Al, or parylene-N) exhibits the desired properties of having a columnar structure, high moisture resistance, and high luminescence. Our process quickly yields high-quality CsI and CsI:Na films with thicknesses greater than 100 μm that exhibit the desired columnar structure and luminescence effect.