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International Society for Industrial Process Tomography

8th World Congress on Industrial Process Tomography

Characteristics of the CsI:Tl Scintillator Crystal for X-Ray Imaging Applications

Maria da Conceição Costa Pereira, Tufic Madi Filho, José Roberto Berretta and Carlos Henrique de Mesquita

Nuclear and Energy Research Institute – IPEN/CNEN-SP Av. Prof. Lineu Prestes, 2242 São Paulo Brazil macoper@ipen.br

ABSTRACT

Scintillators are high density luminescent materials that convert X-rays to visible light. Thallium doped cesium iodide (CsI:Tl) scintillation materials is widely used as converters for X-rays into visible ligh, with very high conversion efficiency of 64.000 optical photons/MeV. CsI:Tl crystals are commercially available, but, the possibility of development of these crystals into different geometric shapes, to meet the need for coupling the photosensor and reduced cost, makes this material very attractive for scientific research. The objective of this work was to study the feasibility of using radiation sensors, scintillators type, developed for use in imaging systems for X-rays. In this paper, the CsI:Tl scintillator crystal with nominal concentration of the 10-3 M, was grown by the vertical Bridgman technique. The imaging performance of CsI:Tl scintillator was studied, as a function of the design type and thickness, because it interferes with the light scattering and, hence, the detection efficiency and the final image resolution. The result of the diffraction X-ray analysis in the grown crystals was consistent with the pattern of a face-centered cubic (fcc) crystal structure, like microfiche 6-311 (IPEN/CNEN-SP laboratory), which corresponds to the structure of CsI. Slices 25x2x3 mm3 (length, thickness, height) of the crystal and mini crystals screens of 1x2x3 mm3 (length, thickness, height) were used for comparison in the imaging systems for X-rays. With these crystals scintillators, images of undesirable elements, such as metals in food packaging, were obtained.

Keywords crystal growth, scintillator, X-ray detection.

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