- Bismuth germanate
Bismuth germanate (BGO, chemical formula Bismuth4Germanium3Oxygen12 (
evlitinestructure) or the less common type Bi12GeO20) is an inorganic chemical compound with main use as a scintillator. It forms cubic crystals.
When subjected to high energy
gamma rays, bismuth germanate emits photons of wavelengths between 375-650 nm, with peak at 480 nm. It produces about 8500 photons per megaelectronvoltof the high energy radiation absorbed. It has good radiation hardness (parameters remaining stable up to 5.104 Gy), high scintillation efficiency, good energy resolution between 5-20 MeV, is mechanically strong, and is not hygroscopic. It has very high density, 7.13 g/cm³ and a high Z value. Its melting point is 1050 °C. It is the most common oxide-based scintillator.
Bismuth germanate is used in detectors in
particle physics, aerospacephysics, nuclear medicine, geology exploration, and other industries. Bismuth germanate arrays are used for gamma pulse spectroscopy. BGO crystals are also used in positron emission tomographydetectors.
Commercially available crystals are grown by the
Czochralski processand usually supplied in the form of cuboids or cylinders. Large crystals can be obtained.
Bismuth germanate has high
electro-optic coefficients, making it useful in nonlinear opticsfor building Pockels cells, and can also be used for photorefractivedevices for ultravioletrange.
* [http://www.mt-berlin.com/frames_cryst/descriptions/scintillators_gen%20.htm Scintillation crystals]
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