1 Bismuth Germanate Bgo Scintillation Crystal Radiation Detector Scintillator

US $750

Ankeny, Iowa, United States
Jun 1st

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THIS AUCTION IS FOR QUANTITY OF ONE (1) BGO CRYSTAL. The purpose of a scintillation crystal such Bismuth Germanate, commonly called BGO for short, is to convert radiation into a visible light. When radiation such as gamma-rays pass through the crystal it scintillates, meaning it gives off a tiny burst of light. The light is too dim and too brief to detect without amplifying it first, so normally a Photo-Multiplier Tube (PMT) is used to amplify the burst of light into an electrical pulse that is used to trigger a Geiger counter or other counting devices. (Please see my other listings for a square faced Hamamatsu PMT that is a perfect match for these crystals). The exact type of this crystal is Bi4Ge3O12 or sometimes known as BGO12. The BGO crystal I am selling is 30mm x 12mm x 6mm. The end faces are 12mm by 6mm, and at least one end is polished (often both ends), the sides are an un-polished matte finish, overall length of each crystal is 30mm. All the crystals I offer are clean and in very good condition with no large chips. Most of the crystals have some minor flaking or roughness on the edges and corners (see pictures below) but this commonly occurs during manufacturing and should not have any measurable effect on performance. The picture below shows how the BGO crystal will actually produce a blue glow while it is being directly hit by a constant radiation beam from an X-ray machine. Once the radiation source is removed the BGO stops scintillating (glowing), the crystal does not become radio-active. This is not the normal application for BGO crystals, its only to help illustrate their scintillation properties. The BGO crystal by itself will not make a good indicator of unsafe levels of radiation in the environment. In order to use a BGO crystal as a radiation detector it will be necessary construct a amplifier/counter circuit using photo-multiplier tube (PMT). (Note: This auction is for a Quantity of ONE (1) BGO crystal). All pictures shown are representative, and all my BGO crystals have the same specs and quality, but exact item shipped will have minor cosmetic differences. This auction is for a Quantity of ONE (1) BGO crystal. FREE SHIPPING FOR US CUSTOMERS !! INTERNATIONAL CUSTOMERS: Shipping by USPS First Class International Mail is $13.95 total for any quantity between 1 and 10 items. (postal delivery time is estimated to be 6 to 10 business days but can be delayed by customs). Thank you for looking! Below is general information on the properties and specifications of BGO: Bismuth Germanate, also called BGO, is a high density scintillation material. Due to the high atomic number of bismuth (83) and its high density, BGO is a very efficient Gamma-ray absorber. Because of its high effective Z value, the photofraction for Gamma-ray absorption is high, which results in a very good photo-peak to Compton ratio. The scintillation light can be detected with standard photomultiplier tubes. The scintillation intensity of Bismuth Germanate is a strong function of the temperature. The decay time of BGO is about 300 ns at room temperature, which is comparable to that of NaI(Tl). However, the afterglow is much lower, typically about 0.005% after 3 ms. BGO is relatively hard, rugged, non-hygroscopic crystal which does not cleave. The material does not show any significant self absorption of the scintillation light. The crystal housing can be kept simple since no hermetic air-tight sealing is required. BGO can be machined to various shapes and geometries. BGO scintillation crystals are used in applications where a high photofraction is required (as in PET scanners) or because of its high density (as in Compton suppression spectrometers). Summary of Properties Density; 7.13 g/cm3 Cleavage plane -- none Hardness; 5 Mho Hygroscopic; no Wavelength of emission maximum; 480 nm Lower wavelength cutoff; 320 nm Refractive index at emission maximum; 2.15 Primary decay time; 300 ns Afterglow (after 3ms); 0.005 % Light yield; 8 - 10 x 103 photons/MeV