Cadmium Tungstate (Cadmium Tungsten Oxide) (CdWO4)-Granules

Characteristic




Cadmium tungstate (CdWO4 or CWO), the cadmium salt of tungstic acid, is a dense, chemically inert solid which is used as a scintillation crystal to detect gamma rays. It has density of 7.9 g/cm3 and melting point of 1325 °C.




Chemical formula：CdWO4

Molar mass： 360.25 g·mol−1

Appearance：colorless crystals with a yellow tint

Density：7.9 g/cm3, solid

Melting point：1,325 °C (2,417 °F; 1,598 K)

Solubility in water：0.04642 g/100 mL (20 °C)




Application




It is often used in computed tomography. Combining the scintillator crystal with externally applied piece of boron carbide allows construction of compact detectors of gamma rays and neutron radiation.




Cadmium tungstate was used as a replacement of calcium tungstate in some fluoroscopes since the 1940s. Very high radiopurity allows use of this scintillator as a detector of rare nuclear processes (double beta decay, other rare alpha and beta decays) in low-background applications.