Low-Afterglow CsI:Tl microcolumnar films for small animal high-speed microCT.

Area of Science:

• Medical Imaging
• Materials Science

Background:

• High-speed microCT systems require scintillators with minimal persistence for ghost-free imaging.
• Conventional cesium iodide thallium (CsI:Tl) microcolumnar films exhibit afterglow, causing image lag and artifacts in high-speed applications.

Purpose of the Study:

• To investigate the potential of codoping CsI:Tl with europium (Eu(2+)) to suppress afterglow in microcolumnar films.
• To evaluate if the afterglow suppression properties of CsI:Tl,Eu crystals are maintained in microcolumnar film form for high-speed microCT.

Main Methods:

• Fabrication of CsI:Tl,Eu microcolumnar films.
• Characterization of afterglow properties using excitation pulses of varying durations (20 ns and 100 ms).
• Comparison of afterglow performance against standard CsI:Tl films.

Main Results:

• Eu(2+) doping in CsI:Tl crystals suppressed afterglow by up to 40 times (2 ms after short pulse) and 15 times (2 ms after long pulse).
• Theoretical modeling suggests Eu(2+) introduces deep electron traps, altering decay kinetics.
• Preliminary results show CsI:Tl,Eu microcolumnar films exhibit a 3.5-fold improvement in afterglow compared to standard CsI:Tl films.

Conclusions:

• Europium codoping effectively reduces afterglow in CsI:Tl materials.
• CsI:Tl,Eu microcolumnar films show promise for high-speed, ghost-free microCT imaging in small animal screening.
• The improved afterglow properties make these films suitable for demanding, high-frame-rate imaging applications.