BGO (Bi4Ge3O12) is a high Z, high density scintillation material. Due to the high atomic number of bismuth (83) and the material's high density of 7.13 g/cm3, BGO is a very efficient gamma ray absorber. Given the high Z value of the material, the photo fraction for gamma ray absorption is high and as a result very good peak-to-total ratios are observed.
The radioactivity in BGO can make BGO unacceptable for some applications. We have developed a production process that significantly reduces the natural background, making our BGO well-suited for most applications.
BGO can be machined to various shapes and geometries. Since BGO is not hygroscopic it does not require a hermetic package. Arrays can be produced for imaging applications such as medical PET and security. For Physics experiments such as anti-Compton shields, crystals are typically packaged into larger annulus type detectors with multiple readout devices such as photomultiplier tubes.
|Melting point [K]||1323|
|Thermal expansion coefficient [C-1]||7 x 10-6|
|Wavelength of emission max. [nm]||480|
|Lower wavelength cutoff [nm]||320|
|Refractive index @ emission max||2.15|
|Primary decay time [ns]||300|
|Light yield [photons/keVγ]||8-10|
|Photoelectron yield [% of NaI(Tl)] (for γ-rays)||15 - 20|
|Neutron capture cross-section||1.47b|
|Afterglow||@ 20ms 150ppm|