4 Chipped Bgo Scintillation Crystal Radiation Detector For Experimenters

US $630

Ankeny, Iowa, United States
May 24th

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This auction is for a lot of FOUR (4) CHIPPED BGO Crystals. Please see my other listings for more information about my BGO crystals in general. The exact type of these crystals is Bi4Ge3O12 or sometimes known as BGO12. Each crystal is 30mm x 12mm x 6mm. The end faces are 12mm by 6mm, only the end face is polished, the sides are an un-polished matte finish, overall length of each crystal is 30mm. The crystals in this auction are partially covered in old paint and have some chips and flaking on the edges and corners. The crystals in this lot for for "Experimenters" on a tight budget that still want to experiment with building their radiation detector probes for Geiger counters and spectrum analyzers. All pictures shown are representative of the general condition, the actual crystals shipped will have cosmetic differences. This auction is for a lot of FOUR (4) CHIPPED BGO crystals. FREE SHIPPING FOR US CUSTOMERS !! INTERNATIONAL CUSTOMERS: Shipping by USPS First Class International Mail is $13.95 for the first lot of 4, and $1.95 for each additional lot of 4. (postal delivery time is estimated to be 6 to 10 business days but can be further delayed when clearing customs). Thank you for looking! Below is general information on the properties and specifications of BGO: 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. 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