Bismuth germanate

Source: Wikipedia, the free encyclopedia.
BGO scintillator crystals covered with a (partly dilapidated) white paint mask
A crystal cylinder rests on a piece of white cloth, which itself sits on a blue surface of a table.
1-inch diameter, 1-inch tall crystal of BGO. BGO degenerates under UV light, so here it is illuminated with an LCD laptop screen to ensure minimal UV exposure.

Bismuth germanium oxide or bismuth germanate is an inorganic chemical compound of

sillenite structure, and Bi2Ge3O
9.)

Bi4Ge3O12

Bi4Ge3O12 has a cubic crystal structure (a = 1.0513 nm, z = 4,

hygroscopic. Its melting point is 1050 °C. It is the most common oxide-based scintillator.[2]

Bismuth germanium oxide is used in detectors in particle physics, aerospace physics, nuclear medicine, geology exploration, and other industries. Bismuth germanate arrays are used for gamma pulse spectroscopy. BGO crystals are also used in positron emission tomography detectors.

Commercially available crystals are grown by the

Czochralski process and usually supplied in the form of cuboids or cylinders. Large crystals can be obtained. Crystal production is typically done around 1100 °C, i.e. around 50 °C above its melting point.[3]

Bi12GeO20

Bi12GeO20 has a cubic crystal structure (a = 1.01454 nm, z = 2,

photorefractive devices for ultraviolet
range.

The Bi12GeO20 crystals are

bismuth oxide and germanium oxide.[7] The crystals are transparent and brown colored.[8]

The crystals of BGO and similar compounds BSO (Bi12SiO20,

ferroelectric
.

The materials can find use in phased-array optics.

When sputtering, the target has to be kept below 450 °C as otherwise the bismuth vapor pressure would get the composition out of stoichiometry, but above 400 °C to form the piezoelectric γ phase.[11]

See also

References

  1. doi:10.1016/0038-1098(82)90575-0
    .
  2. ^ Bismuth Germanate Scintillation Material. crystals.saint-gobain.com
  3. ^ Process for the production of bismuth germanate monocrystals with a high scintillation response. Le Gal et al US Patent 4664744
  4. doi:10.1107/S0567740879010190
    .
  5. ^ Haynes, William M., ed. (2016).
    ISBN 9781498754293
    .
  6. ^ Lam, C.S. (2004) Integration of SAW and BAW Technologies for Oscillator Applications. International Workshop on SiP/Soc Integration of MEMS and Passive Components with RF ICs
  7. S2CID 136720849
    .
  8. ^ "Technology Crystal Growth Laboratory (CGL): single crystals, nanotechnology". www.uam.es. Retrieved 2016-04-09.
  9. ^ "Sillenite Photorefractive Crystals (BGO and BSO) – Alkor Technologies". www.alkor.net. Retrieved 2016-04-09.
  10. ISBN 9783642194092
    .
  11. ISBN 9780815519317
    .

External links
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