小型电子感应加速器电子枪灯丝电源研制  

Development of the electron gun filament power supply for small size betatron

作　　者：刘琦[1] 王海涛[1] 陈海生 王仁波[1] LIU Qi;WANG Haitao;CHEN Haisheng;WANG Renbo(Engineering Research Center for Nuclear Technology Application,Ministry of Education,East China University of Technology,Nanchang 330013,China;Pan-China Detection Technology,Nanchang 330013,China)

机构地区：[1]东华理工大学核技术应用教育部工程研究中心,南昌330013 [2]泛华检测技术有限公司,南昌330013

出　　处：《核技术》2022年第11期37-43,共7页Nuclear Techniques

基　　金：国家自然科学基金(No.12075055);核能开发科研项目(No.20201192);核技术应用教育部工程研究中心开放基金项目(No.HJSJYB2020-4,No.HJSJYB2019-4);江西省自然科学基金项目(No.20202BABL201025)资助。

摘　　要：根据小型电子感应加速器的工作特点,设计了由灯丝占空比调节电路和注入电流反馈电路组成的灯丝电源。通过数字信号处理器(Digital Signal Processor,DSP)输出两路脉冲宽度调制(Pulse-Width Modulation,PWM)信号驱动半桥电路,半桥电路输出正负交替电压脉冲至隔离变压器初级,变压器次级电压加载在灯丝上,供灯丝加热。通过收集加速管管壁电流和靶电流作为注入电流反馈信号,DSP根据反馈信号调节灯丝电压脉冲占空比,实现灯丝发射电流的调整,使灯丝注入到加速管内的电流处在最佳值。实验测试结果表明:灯丝电源可以使加速器输出剂量率保持在最佳状态,输出剂量率稳定度优于11.3%/10 min,灯丝电源满足小型电子感应加速器的需求。[Background]Betatrons are widely used in non-destructive testing,cargo and vehicle security inspection systems,whilst the filament power supply is an important core component of small size betatron.Existing filament power supplies are not suitable for small size betatron.[Purpose]This study aims to develop a novel electron gun filament power supply for small size betatron to produce optimal radiation intensity.[Methods]An electron gun filament power supply composed of a filament duty cycle adjustment circuit and an injection current feedback circuit were designed on the basis of operating characteristics of a small size betatron.Two pulse-width modulation(PWM)signals were output from the digital signal processor(DSP)to drive the half-bridge circuit.Positive and negative alternating voltage pulses were output by the half-bridge circuit to the primary of the isolation transformer,and the secondary voltage of the transformer was loaded to the filament for heating of the filament.By collecting the betatron tube wall current and target current as the injection current feedback signal,the duty cycle of the filament voltage pulse was adjusted by DSP according to the feedback signal,and realizes the adjustment of the filament emission current,so that the current injected by the filament into the acceleration tube was kept at the optimal value.[Results]The experimental test results show that the filament power supply can keep the betatron output dose rate in the best state,and the output dose rate stability is better than 11.3%/10 min.[Conclusions]The filament power supply meets the requirements of small size betatron with advantages of good stability,wide adjustment range and small size.It can be applied to the small size betatron developed by the Engineering Research Center for Nuclear Technology Application of the Ministry of Education of East China University of Technology.

关 键 词：电子感应加速器 灯丝电源 半桥电路 管壁电流 靶电流 

分 类 号：TL99[核科学技术—核技术及应用]