Anhydrous cerium-doped lanthanum bromide and preparation method thereof

Abstract

The invention provides a preparation method of anhydrous cerium-doped lanthanum bromide. The preparation method comprises the following steps: (1) enabling a cerium source to react with a lanthanum source under the existence of bromide ions; (2) melting and cooling a reaction product obtained in the step (1) to obtain the anhydrous cerium-doped lanthanum bromide, wherein the step (1) and the step(2) are performed in a protective atmosphere or under vacuum. The invention provides the anhydrous cerium-doped lanthanum bromide of which the moisture content is lower than 100 ppm. The preparation method provided by the invention effectively solves the problem of non-uniform mixing of a solid and a solid; the operation steps are simple, reaction conditions are easy to reach, and the production cost is low. The anhydrous cerium-doped lanthanum bromide provided by the invention can be directly used for the growth of a cerium-doped lanthanum bromide scintillation crystal, obtained crystal cerium is uniformly distributed, and the performance is better.

Description

technical field [0001] The invention relates to the field of deep processing of rare earth materials. Specifically, the invention relates to a preparation method of anhydrous cerium-doped lanthanum bromide and anhydrous cerium-doped lanthanum bromide powder obtained by the method. Background technique [0002] Ce-doped lanthanum bromide (LaBr 3 The excellent performance of :Ce) scintillation crystal was discovered in 2001. It has very attractive characteristics, such as high photon output (80,000 photons / MeV), which is 2 times that of the existing scintillator (NaI(Tl)) with the highest luminous efficiency. times, and has a fast decay constant and a high damping coefficient. Using radioactive source 137Cs (662keV) γ-rays, it was found that for LaBr doped with 0.3% Ce 3 : The photon output of Ce scintillator is 61000 photons / MeV, LaBr doped with 10% Ce 3 : The photon output of Ce scintillator is up to 80000 photons / MeV. LaBr 3 : The energy resolution of the Ce scintillat...

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Problems solved by technology

[0003] LaBr 3 : It is very difficult to grow large-sized Ce crystals, and the price is extremely expensive. The technical bottleneck lies in the difficulty of preparing high-purity lanthanum bromide and cerium bromide

The prepared raw materials are very susceptible to contamination by oxygen and water, and high impurity content can easily lead to quenching of luminescence

[0004] In the crystal growth preparation stage, the most common way to obtain anhydrous lanthanum bromide / cerium bromide mixture is to prepare anhydrous lanthanum bromide / cerium bromide separately, and then accurately weigh and mix them separately, but the disadvantages of this method are: 1. Uneven mixing, which leads to low performance uniformity at different positions of the single crystal; 2. In order to improve the uniformity of mixing, it is necessary to prolong the melting time, wasting energy and time; 3. Careless handling of the mixing process can easily introduce other impurities

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