Absolute Luminescence Efficiency of Europium-Doped Calcium Fluoride (CaF2:Eu) Single Crystals under X-ray Excitation

Abstract

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.

Optical Characteristics of ZnCuInS/ZnS (Core/Shell) Nanocrystal Flexible Films Under X-Ray Excitation

“…The QD/PMMA films were irradiated utilizing a BMI General Medical Merate X-ray tube (General Medical Merate S.P.A., Bergamo, Italy) with a W anode and filtration equivalent to 2 mm Al, with tube voltages ranging from 50 to 130 kVp. An additional 20 mm filtration was introduced in the beam to simulate beam quality attenuation by a human body [17,[27][28][29][30][31]. The thin films were positioned in an integration sphere (Oriel 70451) and their light output was measured by means of a calibrated photomultiplier in connection with a Keithley Model 6430 Sub-Femtoamp Remote SourceMeter (Keithley Instruments Inc., Cleveland, OH, USA) electric current meter.…”

Dual Energy X-ray Methods for the Characterization, Quantification and Imaging of Calcification Minerals and Masses in Breast

“…Furthermore, hydrogenated amorphous silicon (aSi:H) flat panel detectors coupled with a thallium-doped cesium iodide (CsI:Tl) converter layer have extensively used in dual energy mammography studies [8,9,[21][22][23][34][35][36][37]. Finally, digital X-ray imaging detectors [38][39][40] based on complementary metal oxide semiconductor (CMOS) active pixel sensors (APS) coupled to Gd 2 O 2 S:Tb phosphor screen have been recently introduced in dual energy breast imaging applications [25][26][27][28].…”

Luminescence and stability of Tb doped CaF2 nanoparticles

“…1 The sharp 4f–4f band emission of Ln 3+ ions and their long-lived photoluminescence (PL), 2 low toxicity, and stability against photobleaching make them suitable for use in lighting, photovoltaic, laser, and bio-imaging applications. 3–5 Fluoride host materials, owing to their intrinsic properties including low phonon energy (<400 cm −1 ), low refractive index, high transparency, 6 and wide band gap are considered suitable hosts for Ln 3+ ions to obtain efficient PL. CaF 2 has a wide optical bandgap (12.1 eV) and a well-known face centred cubic crystal structure (where each Ca 2+ is coordinated with eight F − anions, and each F − is coordinated by four Ca 2+ cations) and is considered to be a model host for Ln 3+ ions.…”