CsI ​​crystal (also known as cesium iodide crystal) is one of the scintillation crystals with the highest scintillating efficiency. Pure CsI is also a scintillator, with a very fast decay rate (~10ns), and the peak of the emission spectrum is around 310nm, but its scintillation yield at room temperature is low. The light yield of pure CsI crystal at a low temperature of 77K is as high as 100,000 ph/Mev, which makes pure CsI the most attractive scintillator in the field of cryogenic detectors.

TI: CsI is one of the crystals with the highest scintillating efficiency. The effective wavelength of its emission spectrum is above 500nm, which is very close to the most sensitive detection wavelength of the photodiode. TI: CsI crystal has high light yield, no cleavage surface, low melting point, and is easy to grow. It has a wide range of applications in security detection, neutrino detection, neutrino detection, gamma rays, XCT, and other fields. Sodium-doped cesium iodide (Na: CsI) is an important alkali metal halide inorganic scintillator, which is widely used as a laser thin film and X-ray detection material. The emission peak of the wavelength of Na: CsI is about 420nm, which matches well with the detection wavelength of the photomultiplier tube. Na: CsI is a promising dark matter scientific detection material. However, CsI crystal has an obvious shortcoming that it is easy to deliquesce, so the necessary moisture-proof and sealing measures must be in place.


Material Features

Chemical formulaTI:CsINa:CsICsI
Density (g/cm3)4.514.514.51
Melting point (℃)894621894
Hardness (Mho)222
Solubility (g/100gH2O)N/AN/A/
Thermal expansion coeff (C-1)54*10-654*10-654*10-6

Scintillator Properties

Chemical formulaTI:CsINa:CsICsI
Wavelength(Max. emission) (nm)550420315
Wavelength range (nm)320-300-260-
Decay time (ns)90030016
Light yield (photons/keV)54412
Light output relative to Nal(Tl) (%)45855
Refractive index1.8@550nm1.84 (@420nm)1.95
Radiation length (cm)1.861.861.86
Optical transmission (um)TBATBA/
Transmittance (%)TBATBA/
Reflection loss/surface (%)TBATBA/
Neutron Capture Cross-section (barns)1.47TBA/
Afterglow (%)0.5-5.00.5-5.0/


CsI emission spectrum
CsI decay time
CsI X-ray radioluminscence spectrum
Na-CsI emission spectrum
Na-CsI response waveform
Na-CsI transmission spectrum
TI-CsI Emission spectrum
TI-CsI Transmission spectrum


  • High light yield
  • Short decay time
  • The crystal is easy to grow
  • Good optical and mechanical properties
  • Cheap price


  • γ-ray detection
  • PET  XCT
  • Geological exploration
  • Position sensing detector
  • Security inspection


[1]  Sokolov V O ,  Plotnichenko V G ,  Dianov E M . Centers of near-IR luminescence in bismuth-doped TlCl and CsI crystals[J]. Optics Express, 2013, 21(8):9324-9332.
[2]  Su L ,  Zhao H ,  Li H , et al. Near-infrared photoluminescence spectra in Bi-doped CsI crystal: evidence for Bi-valence conversions and Bi ion aggregation[J]. Optical Materials Express, 2012, 2(6):757-764.
[3]  Lee H S ,  Bhang H ,  Choi J H , et al. Search for Low-Mass Dark Matter with CsI(Tl) Crystal Detectors[J]. Physical Review D, 2014, 90(5):36-47.

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