CaF2(Eu) is a useful scintillator for detecting charged particles and soft gamma-rays up to several hundred keV. Additionally, in crystal form CaF2(Eu) is optically transparent over a wide range from 0.13 to 10µm and widely used to fabricate optical components.
CaF2(Eu) Scintillator Crystals are:
- Good in terms of light emission
- Relatively easily machined into various bespoke configurations
- Chemically inert
- Well suited to use within vacuums as it has a very low vapour pressure
- Robust to both thermal and mechanical shock
- Inherent low background radiation
Issues to be Aware Of:
- Due to its low density and low Z has a low light yield when interacting with high energy gamma-rays
- Has a sharp absorption band at 400nm which partly overlaps the scintillation emission band
Common Applications:
- Medical physics applications
- Phoswich configurations in conjunction with NaI(Tl)
- Specialist applications where robust solutions are required
Optical Properties
| Property |
Units |
Value |
| Wavelength (Max. Emission) |
nm |
435 |
| Wavelength Range |
nm |
395 - 525 |
| Decay Times |
ns |
950 |
| Light Yield |
photons/keV |
30 |
| Photoelectron Yield |
% of NaI(Tl) |
50 |
| Radiation Length |
cm |
3.05 |
| Optical Transmission |
µm |
0.13 - 10µm |
| Transmittance |
% |
TBA |
| Refractive Index |
|
1.47 (@ 435nm) |
| Reflection Loss/Surface |
% |
5.4 |
Mechanical Properties
| Property |
Units |
Value |
| Chemical Formula |
|
CaF2:Eu |
| Density |
g/cm³ |
3.18 |
| Atomic Number (Effective) |
|
16.5 |
| Melting Point |
ºK |
1360 |
| Linear Expansion Coeff. |
C⁻¹ |
19.5 x 10-6 |
| Thermal Conductivity |
Wm⁻¹K⁻¹ |
9.7 |
| Crystal Structure |
|
Cubical |
| Hardness |
Mho |
4 |
| Hygroscopic |
|
No |
| Solubility |
g/100g H₂O |
0.0017 |
Further Reading/Publications
Sizes
| Property |
Value |
| Diameters |
360mm max. |
| Lengths |
150mm max. |
