CsI(Tl) Scintillation Crystals
Cesium Iodide, activated with Thallium - CsI(Tl) - is one of the brightest available scintillators, with a broad emission peaking at 550nm. CsI(Tl) has good stopping power, physically rugged and and well suited to a broad range of applications.


Cesium Iodide - CsI(Tl) - scintillator crystals are:
  • Relatively bright - emitting 54,000 photons/MeV (45% of NaI(Tl))
  • Good absorbers with good stopping powers - density 4.51 g/cm³ and an Effective Z of 54
  • Broadly emitting with a 550nm peak, well matched to use with photodiode
  • Robust with good mechanically characteristics

Cesium Iodide - CsI(Tl) - scintillator crystals have the following issues which should be noted. They:
  • Have a light emission which a is good part is above 500nm, a region where photomultipliers are less sensitive
  • Are relatively slow with a decay time of c.1us
  • Are slightly hygroscopic

Cesium Iodide - CsI(Tl) - scintillator crystals are useful in diverse applications such as:
  • Geological logging
  • Specialist applications in high energy, nuclear, space and medical physics
CsI(Tl) Scintillation Crystals
- Properties -
CsI(Tl) Scintillator Emission Spectrum
CsI(Tl) Mass Attenuation Coefficients
CsI(Tl) Scintillation Crystals
- Optical Properties -
Property Units Value
Wavelength (Max. Emission) nm 550
Lower Wavelength Cut-off nm 320
Decay Times ns 900
Light Yield photons/keV 54
Photoelectron Yield % of NaI(Tl) 45
Radiation Length cm 1.86
Optical Transmission µm TBA
Transmittance % TBA
Refractive Index 1.80 (@550nm)
Reflection Loss/Surface % TBA
Neutron Capture Cross-section barns 1.47
CsI(Tl) Scintillation Crystals
- Mechanical Properties -
Property Units Value
Chemical Formula CsI(Tl)
Density g/cm³ 4.51
Atomic Number (Effective) 54
Melting Point ºK 621
Thermal Expansion Coeff. C⁻¹ 54.0 x 10‾⁶
Cleavage Plane None
Hardness Mho 2
Hygroscopic Slightly
Solubility g/100gH₂0 N/A
CsI(Tl) Scintillation Crystals
- Further Reading/Publications -
CsI(Tl) Scintillation Crystals
- Sizes -
Diameters:
80mm max
Lengths:
400mm max.