Cadmium tungstate

Cadmium tungstate

Cadmium tungstate (CdWO4 or CWO) 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. It is toxic if inhaled or swallowed. Its crystals are transparent, colorless, with slight yellow tint. It is odorless. Its CAS number is CASREF|CAS=7790-85-4. It is not hygroscopic.

The crystal is transparent and emits light when it is hit by gamma rays and x-rays, making it useful as a detector of ionizing radiation. Its peak scintillation wavelength is 520 nm (with emission range between 330-540 nm), and efficiency of 13000 photons/MeV. It has a relative high light yield, its light output is about 40% of NaI(Tl). 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 1940's. [cite web | title=Patterson Hand-Held Fluoroscope (ca. 1940s) | publisher="Oak Ridge Associated Universities" | year=1999 | url=http://www.orau.org/ptp/collection/Radiology/pattersonhandfluorotwo.htm | accessdate=2008-04-26]

Cadmium tungstate films can be deposited by sol-gel technology. Cadmium tungstate nanorods can be synthesized by a hydrothermal process. [cite journal | author=Wang Y, Ma J, Tao J, Zhu X, Zhou J, Zhao Z, Xie L, and Tian H | title=Hydrothermal synthesis and characterization of CdWO4 nanorods | journal=Journal of the American Ceramic Society | volume=89 | issue=9 | pages=2980-2982 | month=Sep | year=2006 | doi= 10.1111/j.1551-2916.2006.01171.x | url=http://www.blackwell-synergy.com/doi/abs/10.1111/j.1551-2916.2006.01171.x | accessdate=2008-04-26]

Similar materials are calcium tungstate (scheelite) and zinc tungstate.

References

External links

* [http://www.mt-berlin.com/frames_cryst/descriptions/scintillators_gen%20.htm Scintillator materials]


Wikimedia Foundation. 2010.

Игры ⚽ Нужно решить контрольную?

Look at other dictionaries:

  • tungstate — [ tœ̃kstat ] n. m. • 1789; de tungstène ♦ Chim. Sel renfermant l anion WO4. Tungstate de sodium (Na2WO4). ⇒ wolfram. ● tungstate nom masculin Sel d un acide tungstique. ● tungstate (synonymes) nom masculin Sel d un acide tungstique. Synonymes …   Encyclopédie Universelle

  • Dictionary of chemical formulas — This is a list of chemical compounds with chemical formulas and CAS numbers, indexed by formula. This complements alternative listings to be found at list of inorganic compounds, list of organic compounds and inorganic compounds by element. Table …   Wikipedia

  • Scintillator — Scintillation crystal surrounded by various scintillation detector assemblies …   Wikipedia

  • CWO — may refer to:*Cadet Warrant Officer, a cadet rank in the British Air Training Corps and the RAF Section of the Combined Cadet Force *Cadmium tungstate, a scintillator *Chief Warrant Officer, a non commissioned rank in the Canadian military *Chief …   Wikipedia

  • Liste de composés inorganiques C — Sommaire 1 Carbone 2 Calcium 3 Cadmium 4 Cérium 5 …   Wikipédia en Français

  • Liste des composés inorganiques C — Liste de composés inorganiques C Sommaire 1 Carbone 2 Calcium 3 Cadmium 4 Cérium 5 …   Wikipédia en Français

  • luminescence — luminescent, adj. /looh meuh nes euhns/, n. 1. the emission of light not caused by incandescence and occurring at a temperature below that of incandescent bodies. 2. the light produced by such an emission. [1885 90; < L lumin (see LUMEN) +… …   Universalium

  • List of inorganic compounds — Tentative listing related to this page, inorganic compounds by element (presently under construction), as well as . This list is not necessarily complete or up to date ndash; if you see an article that should be here but isn t (or one that… …   Wikipedia

  • MÉTALLURGIE - Métallurgie extractive — Le caractère dominant de la métallurgie extractive moderne est que tout métal, quel qu’il soit, peut, pour répondre à un besoin nouveau, devenir un métal industriel. La comparaison des métallurgies particulières fait ressortir des différences… …   Encyclopédie Universelle

  • transition element — Chem. any element in any of the series of elements with atomic numbers 21 29, 39 47, 57 79, and 89 107, that in a given inner orbital has less than a full quota of electrons. Also called transition metal. [1920 25] * * * Any chemical element with …   Universalium

Share the article and excerpts

Direct link
… Do a right-click on the link above
and select “Copy Link”