Lead Tungstate

Lead tungstate is white powder, of which the chemical formula is PbWO₄ and the structure is tetragonal. It can be slightly soluble in water and ammonium chloride solution and decompose in hot hydrochloric acid.

The preparation of lead tungstate is mainly through the reaction of tungsten powder with lead oxide (II) at high temperature, or the heating reaction of tungsten powder and PbO2.

Lead tungstate, the two valence metal tungstate, never been discovered until 90s as a new scintillation crystal of which the scintillation property is significantly different from that of other tungstate crystals. With the rapid development of high energy physics, new requirements for scintillation crystals in electromagnetic calorimeter have been put forward, that is, the requirement of attenuation time and radiation damage is far beyond the requirement of optical output.

Although the luminescence efficiency of PbWO4 crystals is relatively low, its decay time is only ns magnitude. Lead tungstate scintillation crystal is known to have the shortest (except BaF2) decay time and the strongest ability to resist radiation damage. As a result, the European Center for Nuclear Research (CERN) choose it as the preferred scintillation crystal for CMS-ECAL in the construction of its Large Hadron Collider (LHC).

In addition, used as a filler, lead tungstate(PbWO4) can greatly improve the anti radiation ability of the product. And the size of lead tungstate affects the ability to isolate ionizing radiation. When lead tungstate is filled as filler to the protective equipment, the smaller the particle size is, the better protection capability that the protective equipment has.

So, it is important to study the proper synthetic method and strictly control the process conditions to guarantee lead tungstate with ultrafine and uniform particle size.

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