TITLE:
Characteristics of the CsI:Tl Scintillator Crystal for X-Ray Imaging Applications
AUTHORS:
Maria da Conceição Costa Pereira, Tufic Madi Filho, José Roberto Berretta, Carlos Henrique de Mesquita
KEYWORDS:
Crystal Growth, Scintillator, X-Ray, Imaging Systems, Photodiodes, Coupled Charge Device
JOURNAL NAME:
Materials Sciences and Applications,
Vol.9 No.2,
February
7,
2018
ABSTRACT: Scintillators are high-density luminescent materials that convert X-rays to
visible light. Thallium doped cesium iodide (CsI:Tl) scintillation materials are widely used as
converters for X-rays into visible light, with very high conversion efficiency
of 64.000 optical photons/MeV. CsI:Tl crystals are commercially available, but,
the possibility of developing these crystals into different geometric shapes,
meeting the need for coupling the photosensor and reducing 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, since it interferes with the
light scattering and, hence, the detection efficiency plus 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. Slices 25 × 2 × 3 mm3 (length,
thickness, height) of the crystal and mini crystals of 1 × 2 × 3 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. One-dimensional array of photodiodes
and the photosensor CCD (Coupled Charge Device) component were used. In order
to determine the ideal thickness of the slices of the scintillator crystal
CsI:Tl, Monte Carlo method was used.