Research on the Outgassing Performance of TC4 Titanium Alloy and ZrO2 Ceramics Under Ultra-high Vacuum
The inner lined thin-walled vacuum chamber is the core of ion accelerator vacuum system.In order to obtain ultra-high vacuum,there is a high requirement for the outgassing performance of the inner material.Based on a new dual channel outgassing rate test system,the outgassing rate of TC4 titanium alloy and ZrO2 ceramics were completed at room temperature pumping,different baking temperatures and different heating temperatures after baking.The mathematical expressions of outgassing rate at different temperatures were obtained by fitting method.The pres-sure test system of titanium alloy lined chamber was developed,and the pressure distribution under different conditions was obtained by experi-ment and simulation.The result showed that the higher baking temperature,the lower ultimate outgassing rate.Compared to the baking tempera-ture of 150 C,the outgassing rates of alloy and ceramics decreased by 21％at the baking temperature of 250 ℃.After baking,at the tempera-ture between 50 ℃ and 210 ℃,the outgassing rate of the two materials showed an exponentially increasing trend,but the outgassing rate of tita-nium alloy was lower than that of ceramics.Besides,the chamber pressure gradient was relatively smooth in the process of room temperature and baking,but the pressure at the middle position changed greatly under different heating temperatures.When the temperature increased from room temperature to 100 ℃,the middle position pressure increased from 1.41×10-9 Pa to 4.51 ×10-9 Pa.The simulation results were consistent with the experimental results,and the average relative deviation was 6.86％.The above results should fill the outgassing rate database of titanium alloy and ceramics,which could be helpful to predict and evaluate the ultimate pressure of the inner lined thin-walled vacuum chamber under dif-ferent working conditions,and provide support for ultra-high vacuum and extremely high vacuum acquisitions.
ion acceleratorultra-high vacuumTC4 titanium alloyZrO2 ceramicoutgassing ratepressure distribution
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