Method for converting visually yellow cerium doped lutetium yttrium oxyorthosilicate crystals into colorless cerium doped lutetium yttrium oxyorthosilicate crystals in neutral atmosphere

Abstract

The invention discloses a method for converting visually yellow cerium doped lutetium yttrium oxyorthosilicate crystals into colorless cerium doped lutetium yttrium oxyorthosilicate crystals in neutral atmosphere. The visually yellow cerium doped lutetium yttrium oxyorthosilicate crystals are heated in neutral atmosphere for a certain period of time to ensure that oxygen is diffused from the cerium doped lutetium yttrium oxyorthosilicate crystals, so Ce<4+> is changed into Ce<3+>, and the crystals become colorless. According to the method, the crystals are treated at high temperature in neutral atmosphere, so residual oxygen is removed from the crystals, and the visually yellow cerium doped lutetium yttrium oxyorthosilicate crystals are converted into colorless yellow cerium doped lutetium yttrium oxyorthosilicate crystals; therefore, transmissivity of the 420-nm part of the crystals is improved. The scintillation property of the crystals can be improved obviously. By the method, primary crystals are subjected to reduction heat treatment, so the properties of the crystals can be improved, and the properties of the crystal products which are not appropriately oxidized can be recovered. The properties of the crystals are greatly improved, and the utilization rate of the crystals is further improved.

Description

technical field [0001] The present invention relates to cerium doped yttrium lutetium silicate Ce 2x (Lu 1-y Y y ) 2（1-x） SiO 5 The improvement of (LYSO)] crystal processing technology, specifically through special processing to improve the performance of cerium-doped yttrium lutetium silicate, belongs to the field of crystal materials. [0002] Background technique [0003] With the needs of the development of science and technology, inorganic scintillation crystals have huge applications in the fields of imaging nuclear medicine diagnosis (XCT, PET), high-energy physics and nuclear physics, geological exploration and geological morphology, astronomy and space physics, and safety inspection. prospect. They have become one of the indispensable core materials in many modern high-tech fields, and are highly valued by people. [0004] Compared with ordinary plastic polymers, liquids, liquid crystals, and phosphor scintillation materials, inorganic scintillation crystals...

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Problems solved by technology

[0007] In order to improve the luminous intensity of LYSO crystals, it is necessary to carry out high-temperature oxygen diffusion on the crystals to make up for the oxygen vacancies in the crystal growth, but sometimes the crystals are over-oxidized, resulting in the luminescence center Ce of the crystals 3+ Oxidized to Ce 4+ , the color of the crystal turns yellow, and the transmittance decreases at 420nm, and 420nm is its central wavelength of light emission, which seriously affects the scintillation performance of the crystal

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