Cesium Iodide - Sodium Doped

Cesium Iodide is a material with high γ-ray stopping power due to its relative high density and atomic number. Because it has no cleavage plane, it is quite rugged which makes it well-suited for well logging, space research or other applications where rugged solutions are required. CsI is resistant to thermal and mechanical shock. For scintillation counting, it is used either in its undoped form or doped with sodium or thallium.


  • Material – CsI(Na)
  • Density (g/cm3) – 4.51
  • Emission Maximum (nm) – 420
  • Thermal expansion coefficient (c-1) – 54 x 10-6
  • Decay Constant – 0.63 µs
  • Refractive index @ emission max 1.84
  • Conversion Efficiency – 100
  • Light yield (photons/KeVγ) – 41
  • Hygroscopic – Slightly
  • Decay Constant (μs) .63
  • Photoelectron yield [% of NaI(Tl)] (for γ-rays) – 85



  • Oil and gas exploration – well logging
  • Space research and other rugged environment applications
  • Oil and gas exploration – well logging
  • Environmental monitoring
  • Aerial survey


CsI(Na) has the main properties of the CsI matrix (good stopping power, relatively soft and plastic material without cleavage plane), but has a wavelength of emission peak at 420nm. CsI(Na) has a light output of 85% of NaI(Tl). Compared to NaI(Tl), the material interesting where severe environmental conditions are encountered.

High light output, High density, High γ-ray stopping power Suitable for standard PMT readout, Good for harsh environment applications
Environmental, Geophysical, Oil & Gas, General, Space research, Rugged environmental
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