|
BaF2
is relatively hard but is highly sensitive to thermal shock. For its
transmission range is 0.2 μm - 11 μm, the material is used for
optical windows, lenses and prisms in UV-IR. Besides it can also be used
as substrate for some applications. BaF2 is less resistant to
attack by water than CaF2. Pronounced water attack occurs at
500 �C, but in a dry environment the material can be used to 800 �C. BaF2
is grown by modified Bridgman technique. Maximum available size: Dia 200 mm x
Thickness 50 mm. In addition, BaF2 is usually used as
scintillator for gamma detection. It is the fastest scintillating crystals
up to now.
|
Main Specifications
|
|
| Maximum
Size |
Single
Crystal: f100�100
mm
Poly Crystal: f200�100
mm (3
~7 boundaries) |
| Dimension
Tolerance
|
�
0.1mm |
| Flatness
Tolerance |
l
~
l
/10 at 632.8 nm over central 90% of edge
dimensional
|
| Parallelism |
�1 arc sec
~ �3 arc min
|
| Cosmetic
Surface Quality |
10-5 scratch and dig |
|
|
Physical and
optical properties:
|
|
|
Transmission
Range (mm)
|
0.15
~12.5
|
|
Refractive
Index (within 0.26~12.00 mm)
|
1.5122~1.3703
|
|
Reflection
Loss at 10.35 mm
|
5.3%
(2 surfaces)
|
|
Absorption
Coefficient at 6mm (cm-1)
|
3.2�10-4
|
|
Density
(g/cm3)
|
4.89
|
|
Melting
Point (�C)
|
1280
|
|
Thermal
Conductivity at 286K (Wm-1K-1)
|
11.72
|
|
Thermal
Expansion at 273K (K-1)
|
18.1�10-6
|
|
Knoop
Hardness
|
82
with 500g indenter
|
|
Specific
Heat (J Kgm-1K-1)
|
410
|
|
Dielectric
Constant at 1MHz
|
7.33
|
|
Elastic
Coefficients
|
C11
= 89.2 C12 =
40.0 C44 =
25.4
|
|
Apparent
Elastic Limit (Mpa)
|
26.9
(3900psi)
|
|
Possion
Ratio
|
0.343
|
|
Solubility
in 100g water at 23�C (g)
|
0.17
|
|
Cleavage
|
(111)
|
|
|
