NaI(Tl) Scintillation Crystals
Sodium Iodide (Tl) - NaI(Tl) - is a well established and the most extensively used scintillator. It is used for detecting gamma rays of low and intermediate energies. It has a high level of optical output and relatively inexpensive. It is available in both single crystal and polycrystalline formats.

NaI(Tl) scintillators:
  • Are one of the ‘brightest’ scintillators available
  • Have good density and a high Z
  • Have an optical output well match to the maximum sensitivity of commonly available PMTs
  • Have good ‘rad hard’ properties
  • Do not glow in the UV
  • Have an optical output largely independent of temperature

NaI(Tl) scintillators - issues to be aware of:
  • Highly hygroscopic with encapsulation needed


NaI(Tl) scintillators are useful in applications such as:
  • Time-of-Flight measurements
  • Positron lifetime studies
  • Positron Emission Tomography (PET)
  • Specialist applications in nuclear and high energy physics
NaI(Tl) Scintillation Crystals
- Properties -
NaI(Tl) Scintillator Emission Spectrum
LYSO(Ce) Mass Attenuation Coefficients
NaI(Tl) Scintillator Emission Spectrum
NaI(Tl) Scintillation Crystals
- Optical Properties -
Property Units Value
Wavelength (Max. Emission) nm 415
Wavelength Range nm 325 - 550
Decay Times ns 230
Light Yield photons/keV 55
Photoelectron Yield % of NaI(Tl) 100
Radiation Length cm 2.6
Optical Transmission µm 0.15 - 12.5
Transmittance % >90 (0.35 - 9µm)
Refractive Index 1.85 (@415nm)
Reflection Loss/Surface % 6.8
NaI(Tl) Scintillation Crystals
- Mechanical Properties -
Property Units Value
Chemical Formula NaI(Tl)
Density g/cm³ 3.67
Atomic Number (Effective) 56
Melting Point ºK 924
Thermal Expansion Coeff. C⁻¹ 47.4 x 10‾⁶
Cleavage Plane <100>
Hardness Mho 2
Hygroscopic Yes
Solubility g/100gH₂0 TBA (23ºC)
NaI(Tl) Scintillation Crystals
- Further Reading/Publications -
NaI(Tl) Scintillation Crystals
- Sizes -
Diameters:
150 mm max.
Lengths:
400 mm max.
Scintillator/PMT Assemblies