NaI(Tl) – Thallium Doped Sodium Iodide

NaI(Tl) is the most widely used scintillation crystal. Sodium Idoide scintillation crystal has a wide range of applications including environmental measurements, medium energy physics, nuclear medicine and geophysics such as well and oil logging instrumentation.

NaI(Tl) achieves a high light output compared to other scintillator materials and has an emission range compatible with the maximum efficiency of bialkali photocathodes in PMTs.

Sodium Iodide growth methods allow for large crystal sizes to be offered economically, with dopant concentration, material quality and dimensions controllable on request.

NaI(Tl) crystals are typically available from 10mm diameter to 100mm diameter with the below material properties:

Density [g/cm³]	3.67
Melting point [K]	924
Thermal expansion coefficient [K-¹]	47.4 x 10-⁶
Cleavage plane	(100)
Hardness (Mho)	2
Hygroscopic	yes
Wavelength of emission maximum [nm]	415
Refractive index at emission maximum	1.85
Primary decay time [µs]	0.25
Temperature coefficient of light yield	0.3% K-¹
Light yield [photons/MeV γ]	38 x 10³