Speaker
Prof.
Ioannis Kandarakis
(Department of medical instrumentation-Technological Educational Institution of Athens, 12210 Egaleo, Greece)
Description
The light emission performance of the x-ray excited CsI: Tl single crystal
scintillator was investigated as a function of x-ray tube voltage and crystal
thickness. Five CsI: Tl single crystal layers (CRYOS Ltd., Ukraine) with thickness
from 1 to 7 mm were irradiated employing two x-ray tube voltage ranges: (i) The 22 -
45 kV (molybdenum anode-molybdenum filter (Mo/Mo)) range, employed in mammographic
imaging and (ii) The 40-140 kV (tungsten anode-aluminum filter) tube voltage range,
used in general x-ray projection and tomographic imaging. The x-ray luminescence
efficiency (light emission spectrum area over incident x-ray fluence) of the
crystals was determined by performing light emission spectrum and x-ray exposure
measurements. In addition the intrinsic quantum gain (photons created per absorbed
x-ray) and the spectral compatibility to various optical detectors were estimated
from these measurements. The luminescence efficiency was found to be a non-linear
function of crystal thickness and of x-ray tube voltage. Peak efficiency (30.7 )
was observed for the 5 mm thick crystal at 140 kV. A secondary efficiency peak was
observed at 42 (Mo anode) probably due to the effect of the K-photoelectric
absorption edge (at 33 and 35 for Cs and I respectively. For the thicker (6 mm, 7
mm) crystals the efficiency was found to decrease due to light attenuation effects
within the scintillator mass.
Authors
Prof.
Ioannis Kandarakis
(Department of medical instrumentation-Technological Educational Institution of Athens, 12210 Egaleo, Greece)
Mr
Ioannis Valais
(Department of Medical Physics, University of Patras, Patra,Greece and Department of medical instrumentation-Technological Educational Institution of Athens, 12210 Egaleo, Greece)
Co-authors
Mr
Anastasios Gaitanis
(Department of medical instrumentation-Technological Educational Institution, 12210 Egaleo, Greece)
Prof.
Costas Nomicos
(Department of medical instrumentation-Technological Educational Institution, 12210 Egaleo, Greece)
Prof.
Dimitris Giokaris
(Department of Electrical and Computer Engineering, National Technical University of Greece)
Dr
Dimitris Nikolopoulos
(Department of medical instrumentation-Technological Educational Institution of Athens, 12210 Egaleo, Greece)
Prof.
Dionysis Cavouras
(Department of medical instrumentation-Technological Educational Institution, 12210 Egaleo, Greece)
Dr
George Loudos
(Department of Electrical and Computer Engineering, National Technical University of Greece)
Prof.
George Panayiotakis
(Department of Medical Physics, University of Patras, Patra, Greece)
Dr
Ioannis Sianoudis
(Department of Physics, Chemistry and Materials Technology, Technological Educational Institution, 12210 Egaleo, Greece)
Dr
Nektarios Kalivas
(Greek Atomic Energy Commission, 153 10, Ag. Paraskevi P.O BOX 60092, Greece)
Dr
Nikolaos Dimitropoulos
(Department of Medical Imaging, Euromedica” medical center, 2 Mesogeion Ave., Athens, Greece)