一种用于医疗加速器栅控电子枪阴极的研制  

Novel Type of Grid-Controlled Electron Gun for Radiation Therapy Accelerator

作　　者：王小霞[1] 张永清[1] 丁耀根[1] 杜锡九 漆世锴[1] 赵青兰[1] 李云[1] 张琪[1] 孟鸣凤[1] 胡旭华[1] 

机构地区：[1]中国科学院电子学研究所高功率微波源与技术重点实验室,北京100190 [2]广东中能加速器科技有限公司,东莞523808

出　　处：《真空科学与技术学报》2015年第4期468-473,共6页Chinese Journal of Vacuum Science and Technology

基　　金：广东省引进创新科研团队计划资助项目(No:201001D0104732255)

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。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 / cm^2; a 10 μs-wide pulse produced a current density of 24. 1 A/cm^2 at 1000℃. The steady DC current density of 5. 8 A / cm^2,emitted at 950℃,was found to last for 14000 h.

关 键 词：医用加速器 栅控电子枪 覆膜钡钨阴极 寿命 

分 类 号：O462.1[理学—电子物理学]