Absolute Luminescence Efficiency of Europium-Doped Calcium Fluoride (CaF<sub>2</sub>:Eu) Single Crystals under X-ray Excitation
Christos Michail,
Nektarios Kalyvas,
Athanasios Bakas,
Konstantinos Ninos,
Ioannis Sianoudis,
George Fountos,
Ioannis Kandarakis,
George Panayiotakis,
Ioannis Valais
Affiliations
Christos Michail
Department of Biomedical Engineering, Radiation Physics, Materials Technology and Biomedical Imaging Laboratory, University of West Attica, Ag. Spyridonos, 12210 Athens, Greece
Nektarios Kalyvas
Department of Biomedical Engineering, Radiation Physics, Materials Technology and Biomedical Imaging Laboratory, University of West Attica, Ag. Spyridonos, 12210 Athens, Greece
Athanasios Bakas
Department of Biomedical Sciences, University of West Attica, Ag. Spyridonos, 12210 Athens, Greece
Konstantinos Ninos
Department of Biomedical Sciences, University of West Attica, Ag. Spyridonos, 12210 Athens, Greece
Ioannis Sianoudis
Department of Biomedical Sciences, University of West Attica, Ag. Spyridonos, 12210 Athens, Greece
George Fountos
Department of Biomedical Engineering, Radiation Physics, Materials Technology and Biomedical Imaging Laboratory, University of West Attica, Ag. Spyridonos, 12210 Athens, Greece
Ioannis Kandarakis
Department of Biomedical Engineering, Radiation Physics, Materials Technology and Biomedical Imaging Laboratory, University of West Attica, Ag. Spyridonos, 12210 Athens, Greece
George Panayiotakis
Department of Medical Physics, Faculty of Medicine, University of Patras, 265 00 Patras, Greece
Ioannis Valais
Department of Biomedical Engineering, Radiation Physics, Materials Technology and Biomedical Imaging Laboratory, University of West Attica, Ag. Spyridonos, 12210 Athens, Greece
The absolute luminescence efficiency (AE) of a calcium fluoride (CaF2:Eu) single crystal doped with europium was studied using X-ray energies met in general radiography. A CaF2:Eu single crystal with dimensions of 10 × 10 × 10 mm3 was irradiated by X-rays. The emission light photon intensity of the CaF2:Eu sample was evaluated by measuring AE within the X-ray range from 50 to 130 kV. The results of this work were compared with data obtained under similar conditions for the commercially employed medical imaging modalities, Bi4Ge3O12 and Lu2SiO5:Ce single crystals. The compatibility of the light emitted by the CaF2:Eu crystal, with the sensitivity of optical sensors, was also examined. The AE of the 10 × 10 × 10 mm3 CaF2:Eu crystal peaked in the range from 70 to 90 kV (22.22 efficiency units; E.U). The light emitted from CaF2:Eu is compatible with photocathodes, charge coupled devices (CCD), and silicon photomultipliers, which are used as radiation sensors in medical imaging systems. Considering the AE results in the examined energies, as well as the spectral compatibility with various photodetectors, a CaF2:Eu single crystal could be considered for radiographic applications, including the detection of charged particles and soft gamma rays.
