title: In situ synchrotron X-ray powder diffraction for studying the role of induced structural defects on the thermoluminescence mechanism of nanocrystalline LiF.
abstract: The correlation between the thermoluminescence (TL) response of nanocrystalline LiF and its microstructure was studied. To investigate the detailed TL mechanism, the glow curves of nanocrystalline LiF samples produced by high-energy ball-milling were analyzed. The microstructure of the prepared samples was analyzed by synchrotron X-ray powder diffraction (XRPD) at room temperature. Then, the microstructure of a representative pulverized sample was investigated in detail by performing in situ XRPD in both isothermal and non-isothermal modes. In the present study, the dislocations produced by ball-milling alter the microstructure of the lattice where the relative concentration of the vacancies, responsible for the TL response, changes with milling time. An enhancement in the TL response was recorded for nanocrystalline LiF at high-temperature traps (after dislocations recovery starts >425 K). It is also found that vacancies are playing a major role in the dislocations recovery mechanism. Moreover, the interactions among vacancies-dislocations and/or dislocations-dislocations weaken the TL response.
authors.affiliation: Nuclear and Radiological Regulatory Authority, 3-Ahmed El-Zomor Street, El-Zohour District, Nasr City, 11762 Cairo, Egypt.
authors.forename: Mostafa
authors.initials: M
authors.lastname: El Ashmawy
authors.affiliation: Nuclear and Radiological Regulatory Authority, 3-Ahmed El-Zomor Street, El-Zohour District, Nasr City, 11762 Cairo, Egypt.
authors.forename: Hany
authors.initials: H
authors.lastname: Amer
authors.affiliation: Elettra-Synchrotron, SS 14, km 163.5, AREA Science Park, 34149 Basovizza, Trieste, Italy.
authors.forename: Mahmoud
authors.initials: M
authors.lastname: Abdellatief
keywords: dislocation density; kinetics; nanocrystalline microstructure; synchrotron diffraction; thermoluminescence