烧蚀对强脉冲离子束在高分子材料中能量沉积的影响  

Influence of ablation on energy deposition in polymer material under irradiation of intense pulsed ion beam

作　　者：张世健 喻晓[1,2,3] 钟昊玟[1,2,3] 梁国营 许莫非[1,2,3] 张楠 任建慧 匡仕成[1,2,3] 颜莎 Gennady Efimovich Remnev 乐小云[1,2,3] Zhang Shi-Jian;Yu Xiao;Zhong Hao-Wen;Liang Guo-Ying;Xu Mo-Fei;Zhang Nan;Ren Jian-Hui;Kuang Shi-Cheng;Yan Sha;Gennady Efimovich Remnev;Le Xiao-Yun(School of Physics,Beihang University,Beijing 100191,China;Beijing Advanced Innovation Center for Big Data-based Precision Medicine,Beihang University,Beijing 100191,China;Beijing Key Laboratory of Advanced Nuclear Energy Materials and Physics,Beihang University,Beijing 100191,China;National Research Tomsk Polytechnic University,Tomsk 634050,Russia;Institute of Heavy Ion Physics,Peking University,Beijing 100871,China)

机构地区：[1]北京航空航天大学物理学院,北京100191 [2]北京航空航天大学,大数据精准医疗高精尖创新中心,北京100191 [3]北京航空航天大学,先进核能材料与物理北京市重点实验室,北京100191 [4]托木斯克理工大学,托木斯克634050,俄罗斯 [5]北京大学重离子物理研究所,北京100871

出　　处：《物理学报》2020年第11期146-151,共6页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:11175012)资助的课题.

摘　　要：高能量密度纳秒量级强脉冲离子束辐照材料表面的烧蚀产物和束流的相互作用,可能对束流在靶中的能量沉积产生影响,进而影响烧蚀情况下的束流分析和相关应用的优化.本文采用红外成像方法对横截面能量密度1.5-1.8 J/cm^2的强脉冲离子束在304不锈钢和高分子材料上的能量沉积进行了测量分析.结果表明在高分子材料上,在超过一定能量密度后,束流引发材料表面烧蚀产物的屏蔽效应使得大部分束流能量不能沉积在靶上.采用有限元方法对束流引发的温度场分布进行了计算,验证了高分子材料的低热导率以及低分解温度使其在脉冲辐照早期即开始热解,烧蚀产物对后续束流能量的进一步沉积产生屏蔽.此类效应在金属上存在的可能性和对束流诊断等应用的影响,亦进行了讨论.Short-pulse length and high-power density,intense pulsed ion beam(IPIB)has been widely studied in material processing during past decades.Ablation effect plays a great role in the interaction between IPIB and material and may affect the energy deposition of IPIB,thus further influencing the beam application and diagnostics.Therefore,the investigation of ablation effect on energy deposition of IPIB in the irradiated material is of great significance for its applications and diagnostic techniques.In this work,experiments on the IPIB irradiation are carried out on the BIPPAB-450 accelerator at Beihang University.Its maximum accelerating voltage is 450 kV,peak current density is 150 A/cm2,energy density is 1.5–1.8 J/cm2 and pulse duration(FWHM)is 80 ns.Polymer materials which have low thermal conductivity,low decomposition temperature and thus yield to ablation under low beam density,such as polycarbonate(PC),polyvinyl chloride(PVC)and polymethyl methacrylate(PMMA),are chosen in the present research.The 304 stainless steel is used for calorimetric beam diagnostics and comparative analysis.Energy deposition in polymer material and 304 stainless steel are obtained by high infrared imaging diagnostics.It is revealed that the distributions of energy deposition in these two kinds of materials differ from each other obviously.The highest energy density deposited in the 304 stainless steel appears in the center of the irradiated area where focused is the beam with a higher energy density.However,the central energy density in polymer material turns out to be lower than the surrounding area,indicating that a large portion of the ion beam is prevented from reaching the target.Meanwhile,the simulation based on the finite element method is carried out for the thermal filed distribution and evolution under the IPIB irradiation.The simulation result indicates that the strong ablation can be generated on the target surface since the highest temperature caused by IPIB irradiation is much higher than its decomposition temperature.A

关 键 词：强脉冲离子束 烧蚀 能量沉积 屏蔽 

分 类 号：TQ311[化学工程—高聚物工业]