Light emission efficiency and imaging performance of Lu2O3:Eu nanophosphor under X-ray radiography conditions: Comparison with Gd2O2S:Eu

Seferis, I.; Michail, C.; Valais, I.; Zeler, Justyna; Liaparinos, P.; Fountos, G.; Kalyvas, N.; Stoppa, David; Stromatia, F.; Zych, Eugeniusz; Kandarakis, I.; Panayiotakis, G.

doi:10.1016/j.jlumin.2014.02.017

Cited by 41 publications

(33 citation statements)

References 31 publications

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“…In Fig. 9, the MTF of an opaque Gd 2 O 2 S:Eu phosphor screen with grain size about 8 lm and thickness of 91 lm is also shown [9]. The MTF values of this screen are higher than the values of the 67 lm screen film in the low to medium frequency range, though the thickness is slightly higher.…”

Section: Resultsmentioning

confidence: 90%

“…This behavior is typical of detectors based on indirect conversion and is determined by the spatial correlation between adjacent pixels that read the same signal because of the light diffusion. Since the luminescence of the opaque screen of LuPO 4 :5 %Eu was not adequate to give images suitable for image quality evaluation, in this figure the NNPS of a commercial Gd 2 O 2 S:Eu powder phosphor opaque screen, of 91 lm thickness, evaluated in previous study [9], is also shown. The noise of this screen at low to medium frequencies seems to follow a similar pattern with the noise levels of the 100 lm film, while at higher frequencies the noise of the granular phosphor screen has decreasing trend.…”

Section: Resultsmentioning

confidence: 99%

“…In many cases, their scintillation efficiency is also high and in some cases truly extraordinary [9][10][11]. Also LuPO 4 -based phosphors were reported as efficient scintillators [12].…”

Section: Introductionmentioning

confidence: 99%

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On the response of semitransparent nanoparticulated films of LuPO4:Eu in poly-energetic X-ray imaging applications

et al. 2016

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In the present work, we demonstrate the fabrication technique of highly translucent layers of nanoparticulated (*50 nm) LuPO 4 :Eu phosphor, present their basic luminescent properties and give results of their performance in a planar imaging system coupled to a CMOS photodetector. For comparison, the imaging performance of an opaque Gd 2 O 2 S:Eu phosphor screen prepared by sedimentation is also shown. The X-ray detection parameters as well as the luminescence efficiency of the investigated films were discussed. Results show that the in-line transmittance at *600-700 nm, in the range of the phosphor luminescence, varies with respect to the thickness of the films from 40 to 50 % for a film of 67 lm thick to 4-12 % when the thickness increases to 460 lm. Yet, X-ray detection parameters get enhanced as the thickness of the films increases. Those results affect the luminescence efficiency curves of the films under poly-energetic X-ray radiation of various tube energies. The normalized noise power spectrum values were found similar for LuPO 4 :Eu films and a phosphor screen made using commercial Gd 2 O 2 S:Eu powder. The detective quantum efficiency of our films is clearly lower compared to the Gd 2 O 2 S:Eu screen from 2 to 10 cycles mm -1 frequency range while the modulation transfer function is lower from 0 to 5.5 cycles mm -1 frequency range. The acquired data allow to predict that high-temperature sintering of our films under pressure may help to improve their imaging quality, since such a processing should increase the luminescence efficiency without significant growth of the grains and thus without sacrificing their translucent character.

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Section: Resultsmentioning

confidence: 90%

Section: Resultsmentioning

confidence: 99%

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On the response of semitransparent nanoparticulated films of LuPO4:Eu in poly-energetic X-ray imaging applications

et al. 2016

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“…CaWO 4 have reasonable X-ray absorption in the 20-100 keV range (at 50 keV, a 200 μm thick screen absorbs 35% of the X-rays), but rather low X-ray to light conversion efficiency ranging from 4-5% [1,2,5,6]. A semiconductor technology that has been used widely recently is complementary metal oxide (CMOS) semiconductors [7][8][9][10][11][12][13]. Active pixel sensor (APS) CMOS provide high resolution even at high framing rates and, in association with scintillating screens, have been increasingly investigated for medical imaging applications [14].…”

Section: Introductionmentioning

confidence: 99%

Resolution Properties of a Calcium Tungstate (CaWO₄) Screen Coupled to a CMOS Imaging Detector

Koukou

Martini

Valais

et al. 2017

J. Phys.: Conf. Ser.

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Abstract. The aim of the current work was to assess the resolution properties of a calcium tungstate (CaWO 4 ) screen (screen coating thickness: 50.09 mg/cm 2 , actual thickness: 167.2 μm) coupled to a high resolution complementary metal oxide semiconductor (CMOS) digital imaging sensor. A 2.7x3.6 cm 2 CaWO 4 sample was extracted from an Agfa Curix universal screen and was coupled directly with the active area of the active pixel sensor (APS) CMOS sensor. Experiments were performed following the new IEC 62220-1-1:2015 International Standard, using an RQA-5 beam quality. Resolution was assessed in terms of the Modulation Transfer Function (MTF), using the slanted-edge method. The CaWO 4 /CMOS detector configuration was found with linear response, in the exposure range under investigation. The final MTF was obtained through averaging the oversampled edge spread function (ESF), using a custom-made software developed by our team, according to the IEC 62220-1-1:2015. Considering the renewed interest in calcium tungstate for various applications, along with the resolution results of this work, CaWO 4 could be also considered for use in X-ray imaging devices such as charged-coupled devices (CCD) and CMOS.

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“…The last years, research for small-sized sensors, such as nano-phosphors and quantum dots (QDs) is in the spotlight providing noteworthy advances in these fields [1][2][3][4][5][6][7]. A challenge in the production processes of these nano-sensors is the aggregation of the nanoparticles in the polymer matrix, which can reduce fluorescence [8].…”

Section: Introductionmentioning

confidence: 99%

Polymer Based Thin Film Screen Preparation Technique

Valais

Michail

Fountzoula

et al. 2017

J. Phys.: Conf. Ser.

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Abstract. Phosphor screens, mainly prepared by electrophoresis, demonstrate brightness equal to the standard sedimentation on glass or quartz substrate process and are capable of very high resolution. Nevertheless, they are very fragile, the shape of the screen is limited to the substrate shape and in order to achieve adequate surface density for application in medical imaging, a significant quantity of the phosphor will be lost. Fluorescent films prepared by the dispersion of phosphor particles into a polymer matrix could solve the above disadvantages. The aim of this study is to enhance the stability of phosphor screens via the incorporation of phosphor particles into a PMMA (PolyMethyl MethAcrylate) matrix. PMMA is widely used as a plastic optical fiber, it shows almost nearly no dispersion effects and it is transparent in the whole visible spectral range. Different concentrations of PMMA in MMA (Methyl Methacrylate) were examined and a 37.5 % w /w solution was used for the preparation of the thin polymer film, since optical quality characteristics were found to depend on PMMA in MMA concentration. Scanning Electron Microscopy (SEM) images of the polymer screens demonstrated high packing density and uniform distribution of the phosphor particles. This method could be potentially used for phosphor screen preparation of any size and shape.

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Light emission efficiency and imaging performance of Lu2O3:Eu nanophosphor under X-ray radiography conditions: Comparison with Gd2O2S:Eu

Cited by 41 publications

References 31 publications

On the response of semitransparent nanoparticulated films of LuPO4:Eu in poly-energetic X-ray imaging applications

On the response of semitransparent nanoparticulated films of LuPO4:Eu in poly-energetic X-ray imaging applications

Resolution Properties of a Calcium Tungstate (CaWO₄) Screen Coupled to a CMOS Imaging Detector

Polymer Based Thin Film Screen Preparation Technique

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Light emission efficiency and imaging performance of Lu2O3:Eu nanophosphor under X-ray radiography conditions: Comparison with Gd2O2S:Eu

Cited by 41 publications

References 31 publications

On the response of semitransparent nanoparticulated films of LuPO4:Eu in poly-energetic X-ray imaging applications

On the response of semitransparent nanoparticulated films of LuPO4:Eu in poly-energetic X-ray imaging applications

Resolution Properties of a Calcium Tungstate (CaWO4) Screen Coupled to a CMOS Imaging Detector

Polymer Based Thin Film Screen Preparation Technique

Contact Info

Product

Resources

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Resolution Properties of a Calcium Tungstate (CaWO₄) Screen Coupled to a CMOS Imaging Detector