Proton beam dose-mapping via color centers in LiF thin-film detectors by fluorescence microscopy
1 ENEA C.R. Frascati, Fusion and Technologies for Nuclear Safety and Security - Via E. Fermi 45, 00044 Frascati (RM), Italy
2 ENEA C.R. Casaccia, Fusion and Technologies for Nuclear Safety and Security - Via Anguillarese 301, 00123 S. Maria di Galeria (RM), Italy
Received: 11 October 2016
Accepted: 13 March 2017
With the purpose of studying the behavior of novel solid-state lithium fluoride (LiF) films detectors based on the photoluminescence (PL) of radiation-induced defects for proton beam diagnostics and dosimetry, polycrystalline LiF thin films thermally evaporated on glass were irradiated at room temperature in a linear proton accelerator under development at ENEA. The irradiations were performed in air by proton beams of 3 and 7 MeV energy, in a fluence range from 1011 to 1015 protons/cm2. In the LiF films, proton irradiation induces the formation of F2 and aggregate color centers, which simultaneously emit broad PL bands in the visible spectral range under excitation in the blue one. The integrated PL signal, acquired by a fluorescence microscope equipped with a s-CMOS camera, shows a linear dependence on the dose deposited in LiF films, extending from 103 to 106 Gy, independently of the proton energy. A simple theoretical model is put forward for the formation of color centers in LiF and is utilized to obtain a proton beam dose-map by processing the PL image stored in the LiF film detectors.
PACS: 78.55.Fv – Solid alkali halides / 61.72.J- – Point defects and defect clusters / 78.20.-e – Optical properties of bulk materials and thin films
© EPLA, 2017