A method for reducing the breakage rate of quartz tubes during the preparation of scintillation single crystals

Abstract

The invention discloses a method for reducing the breakage rate of quartz tubes during the preparation process of scintillation single crystals. The quartz tube is drawn into a special-shaped quartz tube that is thick at the top and thin at the bottom. The inner wall is coated with a film, and a strain gauge is installed on the outer wall. Through feedback control of the strain amplitude Single crystal growth rate to prevent damage to the quartz tube. After the crystal is formed, turn the special-shaped quartz tube upside down. After cooling to room temperature, take out the scintillation crystal. Advantages of the present invention: coating the inner wall of the special-shaped quartz tube before loading the single crystal raw material can avoid adhesion between the special-shaped quartz tube and the generated crystal, facilitate the complete separation of the generated crystal and the special-shaped quartz tube body, and prevent the quartz tube from being Directly squeezing the crystal helps to reduce crystal microscopic defects, lower the probability of crystal self-absorption, reduce the risk of crystal cracking, and significantly improves the internal performance of the scintillator. In addition, after the crystal growth and cooling is completed, there is no need to break the quartz tube to remove the crystal. Just open the mouth and pour out the crystals, and the quartz tube can be recycled after cleaning.

Description

technical field [0001] The invention belongs to the field of crystal material preparation, in particular to a method for reducing the damage rate of quartz tubes in the preparation of scintillation single crystals. Background technique [0002] Scintillation single crystal materials are usually wide bandgap semiconductor materials. When high-energy photons (such as ultraviolet rays, X-rays, and gamma rays) are incident, a series of complex interactions occur with the lattice of the material, including the photoelectric effect, Compton scattering, and electron pair effects. In this process, the conduction band and valence Many electron-hole pairs are formed in the band and are excited. Electron pairs and holes (eventually forming excitons) then move through the material and are trapped by defects in the forbidden band. Electrons and holes are trapped in the luminescent center and undergo radiative transitions to form scintillation luminescence. By scintillating single crys...

AI Technical Summary

Problems solved by technology

However, the expansion coefficient of the quartz tube is small, and the linear expansion coefficient is only 5×10 in the range of 0 to 1000°C. -6 K -1 , its volume changes very little with temperature, but the expansion coefficient of scintillation crystal material is low, for example, the expansion coefficient of sodium iodide (NaI) is 47.4×10 -6 K -1 , the volume of scintillation crystal material changes greatly with temperature

The traditional quartz tube is in the shape of a cylinder with a pointed tip at the bottom. Due to the difference in expansion coefficient between the two, during the preparation of scintillation single crystals, the quartz tube is very easy to crack as the temperature changes. Once cracked, the air will flow from the When the cracks in the quartz tube enter the sample, the sample will be completely useless once it comes into contact with the air, resulting in the waste of all raw materials, time and energy consumed in the previous preparation process.

Even if the quartz tube is not cracked during the preparation process, it is still necessary to break the quartz tube to take out the crystal after the preparation is successful, so the quartz tube can only be used once, which will cause great waste

What's more serious is that after the quartz tube is broken, the crystal and the quartz tube are seriously adhered. Due to the adhesion force, the crystal has internal cracks and becomes a waste product. The failure rate of the entire preparation process is extremely high, which will cause a great waste of resources. technical problem

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