【摘要】 介绍一种用于移动术中放疗电子直线加速器中栅控电子枪阴极的设计、研制、发射性能测试及其在该加速器中的应用情况。基于栅控电子枪低蒸发、高可靠、长寿命的设计要求,研制出了钨基底平均孔度为21.6%、浸渍311主要单一相铝酸盐、覆Os-W膜浸渍覆膜钡钨阴极。测试结果表明:该阴极在工作温度950℃,直流发射电流密度5.8 A/cm2,在1000℃,脉冲宽度10μs,脉冲发射电流密度24.1 A/cm2,工作温度950℃,直流支取3.0 A/cm2,14000 h寿命发射稳定。该阴极制备栅控电子枪在医疗加速器中获得成功应用。更多还原

【Abstract】 Novel cathode of grid-controlled electron gun for linear accelerator,dedicated to radiation therapy,was developed. The impact of the coating conditions of barium aluminate,including the mole ratio of Ba O: Ca O: Al2O3,sintering temperature and porosity of sponge tungsten substrate,on the emission characteristics of the cathode was investigated. First,single-phased barium aluminate layers were synthesized by dipping the substrate into the molten solution at 1650 ~ 1750℃ with a mole ratio of 3 ∶ 1 ∶ 1,on the sponge tungsten with a porosity of 20% ~22%. Next,the Os-W coating was deposited on the barium aluminate layer by magnetron sputtering. And finally,the thermal emission characteristics of the cathode were measured. The results show that the cathode is capable of emitting a current density high enough for the medical linear accelerator,such as an 18 Me V accelerator. To be specific,at 950℃,the steady DC current density was 5. 8 A / cm2; a 10 μs-wide pulse produced a current density of 24. 1 A/cm2 at 1000℃. The steady DC current density of 5. 8 A / cm2,emitted at 950℃,was found to last for 14000 h.更多还原