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NaI(Tl) Scintillation Crystals
Sodium Iodide crystals have a very high luminescence (scintillation) efficiency and is available in a wide variety of sizes and geometries that makes it the most widely used scintillator. Thallium-doped Sodium Iodide produces one of the highest signals in a PMT per amount of radiation absorbed. It is second only to our Lanthanum Bromide scintillator. Under optimum conditions, an average of 1x 104 photoelectrons are produced per MeV gamma rays.
POLYSCIN® NaI(Tl) scintillation crystals are widely recognized as suitable alternatives to single crystal scintillators in many applications where thermal and mechanical shock are encountered, such as oil and gas exploration. This crystal offers ruggedness combined with a scintillation performance identical to single crystal NaI(Tl).
Uses/Applications
NaI(Tl) crystals are widely used for radiation detection:
- Medical - SPECT (gamma camera), whole body counting, radioimmunoassay (RIA)
- Security - Thermal neutron activation
- Industrial - Thickness or density gauging, coal/mineral assy
- Oil and gas exploration - well logging
- Environmental monitoring
- Aerial survey
- Nuclear physics
Features/Benefits
- High light output
- Available in single crystal & polycrystalline form
- No significant self-absorption of scintillation light
- Emission spectrum well matched with the sensitivity curve of photomultiplier tubes (PMTs) with bialkali photocathodes
NaI(Tl) is hygroscopic and must be hermetically packaged. The proper packaging and integration of scintillation crystals is a science combining advanced design and engineering skills with proven assembly techniques and materials to produce stable, high resolution radiation detectors. Saint-Gobain Crystals offers a variety of detector designs to fulfill most radiation counting applications: a packaged scintillator, a scintillator integrated (permanent or demountable) with a light-sensing device [such as a photomultiplier tube (PMT) or silicon photomultiplier (SiPM)], and a detector with low energy entrance window. Each of those standard detector configurations can be designed with one or more of the various options listed plus integrated electronics.
- Cylindrical: 1" diameter x 1" thick, 2" diameter x 2" thick, 3" diameter x 3" thick, 5" diameter X 5" thick
- Rectangular: 2"x4"x16", 4"x4"x16
- Camera plates: 24" x 18" x 0.375" thick
- Pixellated arrays for use with PMTs or PSPMTs
| Properties | Value |
|---|---|
| Density [g/cm3] | 3.67 |
| Melting point [K] | 924 |
| Thermal expansion coefficient [C-1] | 47.7 x 10-6 |
| Cleavage plane | <100> |
| Hardness (Mho) | 2 |
| Hygroscopic | Yes |
| Wavelength of emission max. [nm] | 415 |
| Refractive index @ emission max | 1.85 |
| Primary decay time [ns] | 250 |
| Light yield [photons/keVγ | 38 |
| Temperature coefficient of light yield | 0.3%C-1 |