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Barium Fluoride is transparent over a wide spectrum range of 0.15-12.5um, and can be manufactured into windows, lens and prisms. It responds to X-rays, gamma rays as well as other high energy particles, which is suitable as a scintillator. It has several scintillation emission bands. The fast one is centered at 220nm with a decay constant of 0.6ns; the slow scintillation band is centered at 310nm with a decay constant of 620ns. It is sensitive to thermal shock and fractures easily.
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Figure 1: External transmittance curve of Barium Fluoride crystal
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Crystal Structure |
Cubic
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cleavage plane |
<111>
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Lattice Constant (Å) |
6.196
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Transparency Range (um) |
0.15 ~ 12.5
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Constant of Dispersion (dn/dT)
(/°C at 0°C and 3.39um )
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dn/dT=-1.45X10-5
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Melting Point (°C)
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1354
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Thermal Conductivity (W/(m K) at 286 K):
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11.72
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Heat Capacity: (J/gK at 276 K):
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0.45
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Linear Coefficient of Thermal Expansion (0°C) ( /°C)
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18.1X10-6
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Refractive Indices |
n=1.47 at 1um
n=1.40 at 10um
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Density (g/cm3) |
4.89
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Mohs Hardness |
3 |
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Young's Modulus (GPa) |
65.4 at <100>
66.3 at <111>
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Shear Modulus (GPa) |
25.1 at <100>
25.3 at <111>
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Poisson Ratio |
0.307 |
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scintillation peak mission (nm) |
220 for fast, 310 for slow
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Decay constant(ns) |
0.6 for fast, 620 for slow |
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Photoelectron Yield [% of Nal(TI)] |
4 for fast, 20 for slow
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Table 1:Barium Fluoride Properties
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