Thallium-doped Sodium Iodide (NaI:Tl) is one of the most widely used and cost-effective scintillation crystals for radiation detection. For decades, it has served as a cornerstone material in nuclear medicine, environmental monitoring, oil well logging, and astrophysics, thanks to its very high light yield, good energy resolution, and reliable performance.
Although NaI:Tl is hygroscopic and requires hermetic sealing, its excellent scintillation efficiency and mature detector technology continue to make it a preferred choice in many radiation detection systems.
Key Properties of NaI:Tl
- Very High Light Yield: Produces strong scintillation signals, enabling high detection efficiency and excellent signal-to-noise performance.
- Good Energy Resolution: Supports effective discrimination of gamma-ray energies for spectroscopy and imaging.
- Fast Scintillation Response: Typical decay time of ~230–250 ns allows rapid data acquisition.
- Hygroscopic Material: Must be hermetically sealed to prevent moisture absorption and preserve optical performance.
Crystal & Scintillation Properties
| Property | Value |
|---|---|
| Chemical Formula | NaI:Tl |
| Density | 3.67 g/cm³ |
| Melting Point | 651 °C |
| Mohs Hardness | 2.1 |
| Refractive Index | 1.85 |
| Emission Peak | 415 nm |
| Decay Constant | ~250 ns |
| Light Yield | ~38,000 photons/keV |
| Thermal Expansion | 47.4 × 10⁻⁶ K⁻¹ |
| Cleavage Plane | (100) |
| Hygroscopic | Yes |
NaI:Tl remains a benchmark scintillator for gamma-ray detection due to its exceptionally high luminescence efficiency.
Typical Applications of NaI:Tl
- Medical imaging (gamma cameras and SPECT systems in nuclear medicine)
- Radiation detection & environmental monitoring (survey meters, fixed radiation detectors, border security)
- Oil & gas well logging (gamma-ray spectrometry for geological formation analysis)
- High-energy & nuclear physics (laboratory radiation measurements)
- Astrophysics & space research (gamma-ray telescopes and cosmic radiation studies)
Shape Optics NaI:Tl Capabilities
Shape Optics Technologies supplies high-quality NaI:Tl scintillation crystals and crystal blanks, supported by over 20 years of optical and crystal manufacturing expertise.
Product & Service Offering
- NaI:Tl scintillation crystals
- High-quality NaI:Tl crystal blank materials
- OEM and custom scintillator solutions
- Hermetically sealed detector options
Why Choose Thallium-Doped Sodium Iodide (NaI:Tl)?
NaI:Tl remains a preferred scintillation material when applications require:
- Maximum light output at competitive cost
- Reliable and well-established detector performance
- Good energy resolution for gamma spectroscopy
Its long history of successful deployment across medical, industrial, environmental, and scientific applications underscores its versatility and value.