Lithium fluoride thin film detectors for low-energy proton beam diagnostics by photoluminescence of colour centres

2016 International Conference on Defects in Insulating Materials

Montereali, R.M.^1 ; Ampollini, A.^1 ; Picardi, L.^1 ; Ronsivalle, C.^1 ; Bonfigli, F.^1 ; Libera, S.^1 ; Nichelatti, E.^2 ; Piccinini, M.^1 ; Vincenti, M.A.^1

ENEA C.R. Frascati, Fusion and Technologies for Nuclear Safety and Security Department, Via E. Fermi 45, Frascati (Rome)

00044, Italy^1

ENEA C.R. Casaccia, Fusion and Technologies for Nuclear Safety and Security Department, Via Anguillarese 301, S. Maria di Galeria (Rome)

00123, Italy^2

关键词: Advanced diagnostics;    Beam diagnostics;    Low-energy protons;    Optically active defects;    Photoluminescence intensities;    Si (100) substrate;    Thin film detectors;    Two Dimensional (2 D);   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/169/1/012012/pdf
DOI  :  10.1088/1757-899X/169/1/012012

来源: IOP

【 摘 要 】

Optically transparent LiF thin films thermally evaporated on glass and Si(100) substrates were used for advanced diagnostics of proton beams of energies from 1.4 to 7 MeV produced by a linear accelerator for protontheraphy under development at ENEA C.R. Frascati. The proton irradiation induces the formation of stable colour centres, among them the aggregate F2and F3+optically active defects. After exposure of LiF films grown on glass perpendicularly to the proton beams, their accumulated transversal spatial distributions were carefully measured by reading the latent two-dimensional (2-D) fluorescence images stored in the LiF thin layers by local formation of these broad-band visible light-emitting defects with an optical microscope under blue lamp excitation. Taking advantage from the low thickness of LiF thin films and from the linear behaviour of the integrated F2and F3+photoluminescence intensities up to the irradiation fluence of ∼5x1015p/cm2, placing a cleaved LiF film grown on Si substrate with the cutted edge perpendicular to the proton beam, the 2-D fluorescence image of the film surface could allow to obtain the depth profile of the energy released by protons, which mainly lose their energy at the end of the path.