NaI(Tl)
Thallium doped Sodium Iodide
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Description
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Hilger Crystals is the major producer of thallium-doped sodium iodide NaI(Tl) in the United Kingdom. |
For many years these scintillation crystals have been supplied to the United Kingdom Energy Authority and stringent production and testing facilities have been developed to ensure the consistent high quality levels demanded by them. |
Crystals are available in a wide range of standard sizes and configurations either as separate crystals or in complete assemblies. |
Thallium-doped sodium iodide crystals are normally encapsulated in aluminium housings with a wall density of 170mg/cm2 and an end cap density of 117mg/cm2. Maximum light transfer is achieved by employing a high efficiency reflector chosen to suit the particular application for which the crystal is required. |
The optical window is made from crown glass specially selected for its low K40 content. Materials used are selected to ensure low background count and, for specific applications, may require a stainless steel or copper housing. |
Properties
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| After Glow |
approx 4.0% after 2ms |
| After Glow |
approx 8.0% after 1ms |
| Cleavage Planes |
(100) |
| Decay Constant (µs) |
0.23 |
| Density (g.cm-3) |
3.70 |
| Emission Spectral Range (nm) |
325 to 525 |
| Gamma and X-ray absorption coefficients (cm-1) |
0.29 at 660keV |
| Gamma and X-ray absorption coefficients (cm-1) |
5.5 at 100keV |
| Light Escape Cone to Air (°) |
44.7 |
| Light Escape Cone to Glass (°) |
56.5 |
| Light Escape from one face to Air (%) |
8.4 |
| Light Escape from one face to Glass (%) |
22.4 |
| Melting Point (°C) |
651 |
| Optical Transmission Range |
250nm to 35µ |
| Peak Scintillation Wavelength (nm) |
410 |
| Photons/MeV |
40,000 |
| Radiation Length (cm) |
2.59 |
| Refractive Index at peak emission |
1.80 |
| Soluble in Alcohol |
Yes |
| Stability |
Very Hygroscopic |
| Structure |
BCC |
| Temperature Coefficient of Light Output (%.K-1) |
+0.08 |
| Thermal Conductivity (W.m-1.K-1 ) |
3.47 at 298K |
| Water Solubility (g/100g H2O) |
159 at 273K |
| Youngs Modulus (GPa) |
9.7 |
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Properties of NaI(Tl)