Scintillation Crystal
Caesium Iodide (CsI)
Highly sensitive crystal with strong scintillation and IR transmission
Caesium Iodide is primarily known as a scintillation crystal, offering high sensitivity to ionising radiation while also providing very broad infrared transmission. It is commonly used in radiation detectors, spectroscopy systems, and specialised sensing applications. CsI is hygroscopic and mechanically soft, so it must be handled and housed carefully in controlled environments.
Is this material right for your application?
Use When:
Scintillation response to ionising radiation is required
Radiation detection or spectroscopy systems are used
Extremely broad infrared transmission is beneficial
Optical sensitivity is prioritised over mechanical durability
The environment can be tightly controlled for moisture
Avoid When:
High humidity or moisture exposure cannot be avoided
Mechanical durability or scratch resistance is required
Components must operate outdoors or in uncontrolled environments
Long-term optical stability without sealing is required
Consider Alternatives:
Potassium Bromide (KBr) – lower cost for FTIR applications
Sodium Chloride (NaCl) – simpler IR spectroscopy setups
KRS-5 – broader IR transmission where scintillation is not required
Explore Related Optical Materials
Potassium Bromide (KBr)
Sodium Chloride (NaCl)
Zinc Sulphide (Multispectral)
Material specifications and frequently asked questions
FAQ
Q1. What wavelength range does CsI cover?
CsI transmits from the UV (~200 nm) to the far-infrared (~50 µm).
Q2. Is CsI hygroscopic?
Yes. CsI is highly hygroscopic and must be protected from moisture at all times.
Q3. Where is CsI commonly used?
CsI is widely used in scintillation detectors and infrared spectroscopy.
Q4. What are alternatives to CsI?
KBr, NaCl, and ZnSe depending on spectral range and environmental constraints.
CsI is extremely soft and easily damaged.
Optical polishing and coating require specialist handling.
Not suitable for open-air or industrial environments.