Barium fluoride (BaF2) window
PRODUCT CATEGORIES
- Excellent transmittance between 200nm – 12μm.
- Resistant to high-energy radiation.
- Non coated version can provide high transmittance.
- Barium fluoride is a fast scintillator that can be used to detect X-rays, gamma rays or other high-energy particles, such as 511 keV gamma photons in positron emission computed tomography (PET). BaF2 can also be used to detect high-energy neutrons or to separate them from simultaneous gamma photons by using pulse shape discrimination technology.
- Barium fluoride (BaF2) has an optical transmittance of nearly 90% in the spectral range of 200-9500nm. It is commonly used in cryogenic imaging systems, lenses, beam splitters, filters, prisms and windows in laser optical systems. The material has a certain water solubility and is only suitable for use in dry environments. BaF2 is not found in a natural state and must be synthesized by chemical methods, which makes the production cost of BaF2 relatively high. Barium fluoride is easy to crack and is very sensitive to thermal shock. It polishes well and can be etched. The purest VUV materials can reach fast scintillation levels.
- Application: Barium fluoride is used in spectral components. It is generally suitable for applications in the passive infrared band (8 to 14μm) and is often used as a viewport window for thermal imaging. At the same thickness, the transmittance of CaF2 extends about 1μm into the infrared region. The highest quality BaF2 also has applications as the fastest known scintillator material and is used in high-energy physics experiments.
- Note: these optical windows are very sensitive to thermal shock.
Technical parameters
| Items | Parameters |
|---|---|
| Material | Barium fluoride (BaF2) |
| Processable shapes | Circles, rectangles, polygons and other shapes |
| Diameter | 3mm-300mm ± 0.1mm |
| Center thickness tolerance | ± 0.05mm (we can process to ± 0.01mm with high precision) |
| Center deviation | 3′(we can process to 30 ″with high precision) |
| Surface accuracy | Reflection PV is better than 1/4λ, transmission PV is better than 1/10λ |
| Surface quality | 40/20 (we can process to 10-5 with high precision) |
| Effective caliber | ≥90% |
| Coating | According to the custom requirements |
Barium fluoride BaF2 transmission curve
In addition, We can customize the optical window according to customer requirements or drawings.
For details, please consult:
Physical and chemical properties of barium fluoride BaF2
| Density (g/cm3) | 4.89 |
|---|---|
| Melting point (℃) | 1280 |
| Thermal expansion coefficient (1/℃) | 1.81*10^-6@-100……+200 |
| purity(%) | 99.9996 |
| Bulk modulus (GPa) | 56.4 |
| Shear modulus (GPa) | 25.4 |
| Thermal conductivity (J/k.m.s) | 11.72@286K |
| Heat capacity (J/g.k) | 0.410@300K |
| Knoop hardness (kg/mm2) | 82 |
| Water solubility (g/l) | 1.7 |
| Young's modulus(GPa) | 53.07 |
| Poisson's ratio | 0.343 |
Optical properties of barium fluoride BaF2
| Transmission wavelength range | 150nm-12500nm |
|---|---|
| Absorption coefficient (1/cm) | 3.2*10^-6@632.8nm |
| Thermo-optic coefficient, dn/dT (1/K) | -15.2*10^-6%@400nm |
| -12.7*10^-6%@3390nm（-60℃） | |
| -15.2*10^-6%@3390nm（+60℃） |
Variation of the refractive index of barium fluoride BaF2 with wavelength
| Wavelength (nm) | Refractive index (n) | Wavelength (nm) | Refractive index (n) |
|---|---|---|---|
| 260 | 1.51 | 5140 | 1.45 |
| 300 | 1.50 | 6500 | 1.44 |
| 360 | 1.49 | 8000 | 1.43 |
| 480 | 1.48 | 8600 | 1.42 |
| 850 | 1.47 | 9200 | 4.41 |
| 3240 | 1.46 | 9800 | 1.40 |
Window Materials Quick Guide
| Wavelength range | Window material |
|---|---|
| 180 nm - 8.0 μm | Calcium Fluoride CaF2 |
| 185 nm - 2.1 μm | UV Fused Silica |
| 200 nm - 5.0 μm | Sapphire |
| 200 nm - 6.0 μm | Magnesium fluoride MgF2 |
| 600 nm - 16 µm | Zinc Selenide ZnSe |
| 1.9 - 16 μm | Germanium single crystal Ge |
| 2 - 5 μm | Barium fluoride BaF2 |
Related Products
