Method for preparing high-temperature inorganic scintillation crystal

Abstract

The invention provides a method for preparing a high-temperature inorganic scintillation crystal. According to the method, crystal growth is performed by adopting a molybdenum metal, tungsten metal crucible or molybdenum and tungsten alloy crucible instead of a conventional iridium metal crucible; valence transformation of doped cerium ions can be avoided while the crucible material is protected from oxidation by adopting a reductive atmosphere instead of conventional single nitrogen or argon crystal growing atmosphere, so that the crystal growth preparation cost can be greatly reduced, and high-quality crystal can be obtained.

Description

technical field [0001] The invention relates to the field of radiation detection materials, in particular to a preparation method of high-temperature inorganic scintillation crystals. Background technique [0002] Inorganic scintillation crystals are crystalline energy converters that can convert the energy of high-energy photons (X / γ-rays) or particles (protons, electrons, etc.) into easily detectable ultraviolet / visible photons. Scintillation crystals can be made into detectors, and scintillation crystal detectors have great application prospects in the fields of high-energy physics, nuclear physics, imaging nuclear medicine diagnosis (XCT, PET), geological exploration, astronomy and space physics, and safety inspection. With the rapid development of nuclear science and technology and other related technologies, its application fields are constantly expanding. Different application fields also put forward more and higher requirements for inorganic scintillators. Tradition...

AI Technical Summary

Problems solved by technology

One is the high cost of preparation: the current conventional crystal growth technology must use an iridium crucible as a container and an induction heating body for crystal growth, and the price of iridium is expensive (the price per kilogram of iridium exceeds 100,000 yuan, and each crucible depends on the size The weight is generally 3 to 10 kg. At the same time, the processing cost of the iridium crucible and the processing loss of iridium are very large, resulting in a high cost of crystal growth.

Second, there are serious defects in the inner packaging of the crystal: the melting points of LYSO and LSO exceed 2100°C, and the melting points of YAG and LuAP exceed 1900°C. The conventional crystal growth technology must use an iridium crucible as a container for induction crystal growth, but such a high growth temperature has already Reaching the working limit of the iridium crucible, the iridium metal in the crucible is particularly easy to be oxidized into impurities and enter the melt, forming inclusions, resulting in the failure of the crystal to be used normally

The third is that the crystal scintillation performance fluctuates greatly: the luminescence center of silicate and aluminate scintillation crystals is Ce 3＋ , which substitutes for the matrix cation (Lu 3＋ , Y 3＋ etc.) into the crystal, because the radius difference between the two is large, Ce 3＋ In silicate crystals, the segregation coefficient is low (k=0.28), resulting in Ce 3 The distribution of + is extremely uneven, and the cerium ions in the crystal mainly form Ce 3＋ exists, partly Ce 4＋ , growth and annealing atmospheres will affect the distribution and ratio of the two

There is competition between the two Ce lattice points for luminescence, which will also reduce the energy resolution of the crystal

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