Thallium Doped Cesium Iodide CsI(Tl)
Thallium doped cesium iodide is one of the brightest scintillators with the fluorescence spectrum with maximum at 550 nm, which allows using photodiodes for detection of the emission. Because a scintillator-photodiode pair can be used, it is possible to reduce significantly the size of the detection system, to do without a high-voltage power supply, and to use the detection system in magnetic fields. CsI(Tl) has a high effective atomic number and consequently larger cross-section of the gamma-radiation photoabsorption.
For practical application, it is very important that CsI(Tl) is not hygroscopic. With relatively good radiation hardness (103 rad) it is applied in high-energy physics. Depending on growth conditions CsI(Tl) crystals can be obtained with low afterglow for application in tomographic systems.
- high mechanical hardness
- long wavelength emission
- good matching with Si photodiode readout