Bismuth Silicate & Bismuth Germanate (BSO & BGO)
|
Basic Properties |
Crystal |
Bi12SiO20 (BSO) |
Bi12GeO20 (BGO) |
Symmetry |
Cubic, 23 |
Cubic, 23 |
Melting Point |
900 °C |
930 °C |
Density |
9.2 g/cm³ |
9.2 g/cm³ |
Mohs Hardness |
4.5 |
4.5 |
Transparencey Range |
450 – 7500 nm |
470 – 7500 nm |
Transmittance at 633 nm |
69% |
67% |
Refractive Index at 633 nm |
2.54 |
2.55 |
Dielectric Constant |
56 |
40 |
Electro-optic Coefficient |
r41 = 5 x 10-12 m/V |
r41 = 3.4 x 10-12 m/V |
Resistivity |
5 x 1011W-cm |
8 x 1011W-cm |
Loss Tangent |
0.0015 |
0.0035 |
Comparison, BGO, CWO |
|
|
|
Properties of scintillation crystals |
|
|
|
Crystal |
BGO |
CWO |
|
Item |
Bi4Ge3O12 |
CdWO4 |
|
Effective atomic number |
75 |
65 |
|
Density (g/cm³) |
7.13 |
7.90 |
|
Decay constant (ns) |
300 |
5000 |
|
Light output (%) |
12 |
39 |
|
Maximum emission wavelagth (nm) |
480 |
540 |
|
Refractive index |
2.15 |
5.25 |
|
Sensitivity to moisture |
None |
None |
|
Cleavage |
None |
Yes |
|
Attenuation coefficient |
X-ray 150 KeV |
9.84 |
7.64 |
(cm-1) |
Y-ray 511 KeV |
0.955 |
0.856 |
|
Characteristics |
Application |
|
GSO |
Short decay time |
High performance |
|
Positron CT |
|
|
|
BGO |
Better absorption of |
Positron CT |
|
Radioactive rays |
Detection of high energy |
|
|
Because of its large |
Partidle in the field of |
|
|
Effective atomic number |
Fundamental physics |
|
|
CWO |
Large light output, which enables the use of silicon photo diode |
X-ray CT |
|