第19卷 第1期 太赫兹科学与电子信息学报Vo1.19，No.1 2021年2月 Journal of Terahertz Science and Electronic Information Technology Feb.，2021 文章编号：2095-4980(2021)01-0176-05Geant4模拟质子入射InP产生的位移损伤白雨蓉，贺朝会，谢 飞，李永宏，臧 航(西安交通大学核科学与技术学院，陕西西安 710049)摘 要：磷化铟(InP)作为重要的第二代半导体材料，禁带宽度大，电子漂移速度快，抗辐照性能比Si,GaAs好，可作为制备空间飞行器上电学器件的备选材料。
随着半导体器件的尺寸纳米化，空间环境中低能质子辐照元件所导致的位移损伤成为影响元件电学性能的主要因素之一。
本文使用Geant4模拟得到低能质子入射InP产生的初级撞出原子(PKA)种类及占比和不同能量质子的非电离能量损失(NIEL)的深度分布。
结果表明：质子俘获和核反应的概率随质子能量的增加而增加，进而使弹性碰撞产生的反冲原子In,P的占比减少，其他反冲原子占比增加；NIEL峰值随质子能量的增加而降低，且NIEL峰有向前移动的趋势，即随着质子能量增加，位移损伤严重区域逐渐由材料末端移至材料表面。
关键词：非电离能量损失模型；Geant4；空间质子辐射；磷化铟中图分类号：TN304.2＋3文献标志码：A doi：10.11805/TKYDA2019383Geant4 simulation of displacement damage induced by proton irradiation in InPBAI Yurong，HE Chaohui，XIE Fei，LI Yonghong，ZANG Hang(School of Nuclear Science and Technology，Xi’an Jiaotong University，Xi’an Shaanxi 710049，China)Abstract：As an important second-generation semiconductor material, indium phosphide has wide bandgap, fast electron drift and better radiation resistance than Si and GaAs. It can be used as analternative material for the preparation of electrical devices on space vehicles. With the nano-size ofsemiconductor devices, the displacement damage caused by low-energy proton irradiation in spaceenvironment is one of the main factors affecting the electrical properties of components. In this paper, thetypes and proportions of Primary Knock-on Atom(PKA) produced by low energy protons irradiation and thedepth distribution of Non-Ionizing Energy Loss(NIEL) of protons with different energies are obtained byGeant4 simulation. The results show that the probability of proton capture and nuclear reaction increaseswith the increase of proton energy, which decreases the proportion of recoil atoms In and P and enhancesother recoil atoms in elastic collision. The NIEL peak tends to move forward in depth of the bulk materialwith the increase of proton energy, which means the area of serious displacement damage gradually shiftsfrom the end of the material to the surface of the material.Keywords：Non-Ionizing Energy Loss；Geant4；space proton irradiation damage；InP对半导体器件的位移损伤研究始于20世纪70年代，主要以地面辐照试验为主，M Yamaguchi, R J Walters 等[1-4]对InP,GaAs,GaN等III-V族化合物半导体材料做了一系列的粒子束辐照实验，得到位移损伤对III-V族半导体器件电学性能的影响规律。
a r X i v :n u c l -e x /0305029v 2 4 J u l 2003Ω−and ¯Ω+production in Pb+Pb and p+p collisions at 30,40and 158A ·GeVMichael Mitrovski for the NA49Collaboration +,∗Institut f¨u r Kernphysik,August-Euler-Strasse 6,60486Frankfurt,Germany E–mail:Michael.Mitrovski@cern.chAbstract.We report preliminary results on Ω−and ¯Ω+production in central Pb+Pb collisions at 30,40and 158A ·GeV and p +p interactions at 158GeV.The midrapidity ¯Ω+/Ω−ratio is estimated to be 0.45±0.05and 0.41±0.18for central Pb+Pb collisions at 158and 40A ·GeV,respectively.The corresponding value for 158GeV p+p interactions is 0.67±0.62.For central Pb+Pb collisions at 158A ·GeV fully corrected distributions are obtained.The inverse slope parameters of the m T spectrum and totalyields are T (Ω−)=276±23MeV,<Ω−>=0.47±0.07and T (¯Ω+)=285±39MeV,<¯Ω+>=0.15±0.02.1.IntroductionA non-monotonic energy dependence of the K +/π+ratio with a sharp maximum close to30A ·GeV is observed in central Pb+Pb collisions [1,2].Within a statistical model of the early stage [3],this is interpreted as a sign of the phase transition to a QGP,which causes a sharp change of the energy dependence of the strangeness to entropy ratio.This observation naturally motivates us to study the production of multistrange hyperons (Ξ,Ω)as well as the function of the beam energy.Although this is the main motivation for our study of Ωproduction in p+p and Pb+Pb collisions,there are two other pointsof interest.In fact,Ω−and ¯Ω+production in p+p collisions could give quite detailed information on the dynamics of strangeness production in those collisions.From string-hadronic models,it is expected that the ¯Ω+/Ω−ratio in p+p interactions at SPS energies is higher than 1whereas it is predicted to be smaller than 1in a hadron gas model [4].Furthermore it was suggested that the kinematic freeze-out of Ωtakes place directly at hadronization [5].If this is indeed the case,the transverse momentum spectra of the Ωdirectly reflect the transverse expansion velocity of a hadronizing QGP [6].In this report we show preliminary results on Ω−and ¯Ω+production in central Pb+Pb collisions at 30,40and 158A ·GeV and compare them to data from p+p interactions at158GeV.We also show fully corrected rapidity and m T spectra of Ω−and ¯Ω+in central Pb+Pb collisions at 158A ·GeV.Integration of the rapidity spectra gives the total yieldof Ω−and ¯Ω+in full phase space.+Presented at Strange Quark Matter 2003,Atlantic Beach,North Carolina,USA∗For a full author list of NA49Collaboration see [1]2.The NA49experimentThe NA49detector[7](see Fig.1)is a large acceptance hadron spectrometer at the CERN SPS,consisting of four TPCs.Two of them,the Vertex TPCs(VTPC),are inside a magneticfield for the determination of particle momenta.The ionisation energy loss (dE/dx)measurement in the two Main TPCs(MTPC),which are outside the magnetic field,is used for particle identification.Figure1.The NA49experimental setup.Target configurations used for central Pb+Pbcollisions and p+p interactions are shown separately.Central collisions were selected by a trigger using information from a downstream calorimeter(VCAL),which measures the energy of the projectile spectator nucleons. 3.Analysis and data setsTheΩ−production is analyzed using its decay channel:Ω−→Λ+K−(BR=67.8%[8]) andΛ→π−+p(BR=63.9%[8]).For¯Ω+the charge conjugated channel is used.For the Ω−(¯Ω+)analysis allΛ(¯Λ)candidates with a reconstructed invariant mass close to the nominal value(|∆MΛ|<0.005GeV/c2)are combined with the K−(K+)candidates.In order to identify the secondary vertex,both are extrapolated back to the target and the point of the closest approach is calculated[9].The resulting combinatorial background is reduced by applying various cuts.The contribution of falseΛ(¯Λ)candidates can be re-duced by selecting the decay(anti-)proton candidates using their energy loss in the TPCs. The same procedure is used to reduce background in the sample of K−(K+)candidates. The reconstructedΩ−(¯Ω+)candidates have to point to the interaction vertex,while the K−(K+)candidate and theΛ(¯Λ)candidate should miss it.Fig.2shows the invariant mass distribution ofΩ−(¯Ω+)candidates in central Pb+Pb at158A·GeV(left),40 A·GeV(middle)and p+p at158A·GeV(right).Only pairs in the kinematical regions specified in table1were used infigures.Events kinematical region 3.5·106|y |<1.0,p t >0.9GeV/cPb+Pb at 40A ·GeV72.5·106|y |<0.75Table 1.Number of analyzed events,percentage of the total inelastic cross sectionselected by the trigger σ/σinel and Ω−(¯Ω+)kinematical region used for the analysis defined by cuts in c.m.rapidity y and transverse momentum p t .A clear signal at the expected mass position (M Ω=1.67245GeV /c 2[8])is seen forall studied reactions.To estimate the number of Ω−(¯Ω+)decays,the number of entries was integrated in the invariant mass interval [M Ω−∆M ,M Ω+∆M ]with ∆M =0.010GeV /c 2and the background contribution was subtracted using a polynominal in-terpolation.Figure 2.The invariant mass distributions of ΛK −(upper row)and ¯ΛK +(lower row)candidate pairs in central Pb +Pb at 158A ·GeV (left),40A ·GeV (middle)and p +p at 158GeV (right).The polynominal parametrisation of the background is indicated by solid lines.For the 158A ·GeV Pb+Pb events the raw signals were corrected for the branching ratios,the geometrical acceptance and reconstruction efficiency [10].4.Results4.1.Energy dependence of the ¯Ω+/Ω−ratio The procedure presented in the previous section allows us to estimate the uncorrected¯Ω+/Ω−ratios in the acceptance given in table 1.The results are given in table 2.¯Ω+/Ω−0.45±0.05Pb+Pb at40A·GeV0.67±0.62Table2.Uncorrected¯Ω+/Ω−ratios at midrapidity for various studied reactions. The errors are statistical only.In Fig.3(left)the NA49¯Ω+/Ω−ratios as a function of the collision energy(√spectra are shown in Fig.4.They arefitted by the exponential function p2t+m2Ω1=C·e−m t/T(1) dm t dywhere thefit parameters are a normalization factor C and the inverse slope parameter T.Thefirst data point(m t−m0<0.25GeV),was excluded from thefit.The slope parameter is similar forΩ−and¯Ω+:T(Ω−)=276±23MeV and T(¯Ω+)=285±39 MeV[10].Our values agree with those measured by the WA97collaboration[14].The large acceptance of the NA49experiment allows us to measure theΩ−(¯Ω+)spectraFigure 4.The transverse massspectra (NA49preliminary)of Ω−(left)and ¯Ω+(right)in central Pb +Pb at 158A ·GeV,measured in the rapidity range 1.9<y <3.9.The lines show fits with an exponential.in a large rapidity interval.Fig.5shows the rapidity distributions for Ω−(left)and ¯Ω+(right)+(right)in central Pb +Pb at 158A ·GeV.The full symbols are the measured points and the open points shows their reflection with respect to midrapidity.Both spectra were fitted by a Gaussian.The width of the Ω−distribution (σ(Ω−)=1.0±0.2)seems to be larger than the one of the ¯Ω+(σ(Ω−)=0.7±0.1).Mean multiplicities in full phase-space were estimated as integrals over measured points corrected for the missing rapidity coverage using the Gaussian parametrisations.The resulting yields are<Ω−>=0.47±0.07and <¯Ω+>=0.15±0.02,where the errors are statistical only.5.Conclusions and outlookPreliminary results on Ω−and ¯Ω+production in Pb+Pb collisions and p+p interactions at CERN SPS energies were presented.The ¯Ω+/Ω−ratios increase with energy from about 0.5at SPS to about 1at RHIC energies for both central Pb+Pb (Au+Au)and p+p interactions.The energy dependence of the antibaryon/baryon ratio is weaker for particles with ahigher strangeness content.Fully corrected spectra ofΩ−and¯Ω+were presented at158 A·GeV.Figure6.The invariant mass distribution ofΛK−+¯ΛK+candidate pairs in centralPb+Pb at30A·GeV.In2002,Pb+Pb collisions at20A·GeV and30A·GeV were taken in the interesting range between top AGS and low SPS energies.Fig.6shows thefirstΩ−+¯Ω+invariant mass spectrum at30A·GeV.Analysis of the data at20,30and80A·GeV is planned for the near future.AcknowledgmentsThis work was supported by the Director,Office of Energy Research,Division of Nuclear Physics of the Office of High Energy and Nuclear Physics of the US Department of Energy(DE-ACO3-76SFOOO98and DE-FG02-91ER40609),the US National Science Foundation,the Bundesministerium f¨u r Bildung und Forschung,Germany,the Alexander von Humboldt Foundation,the UK Engineering and Physical Sciences Research Council, the Polish State Committee for Scientific Research(2P03B13023,SPB/CERN/P-03/Dz446/2002-2004,2P03B02418,2P03B04123),the Hungarian Scientific Research Foundation(T032648,T14920and T32293),Hungarian National Science Foundation, OTKA,(F034707),the EC Marie Curie Foundation,and the Polish-German Foundation. 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HL⁃2A装置中杂质离子温度与旋转速度的时间分布作者：刘科汛来源：《现代电子技术》2013年第21期摘要：在大、中型托卡马克装置中，依赖于中性束注入的电荷交换复合光谱诊断（CXRS）可以方便的测得杂质离子的浓度、温度以及环向旋转速度等参数。
通过电荷交换复合光谱诊断（CXRS）系统对西南核工业物理研究所HL⁃2A装置进行光谱信息的采集，得到了第19591炮第8道的数据，通过Matlab程序对数据进行分析得出离子温度以及环向旋转速度的时间分布，从结果中可以看出，离子温度以及旋转速度的时间分布与中性束注入的功率变化趋势基本一致。
关键词：电荷交换复合光谱；最小二乘法；离子温度；环向旋转速度；时间分布中图分类号： TN911.7⁃34 文献标识码： A 文章编号： 1004⁃373X（2013）21⁃0138⁃030 引言电荷交换复合光谱（CXRS）是粒子诊断和光谱诊断的综合，电荷交换复合光谱在可见光区，光学系统比较容易设计。
在高温等离子体中可以直接利用杂质在可见光区的辐射如CVI （529.5 nm）、OIX（607.0 nm）和HeII（468.6 nm）等进行测量。
因此通过电荷交换复合光谱（CXRS）可以方便的测得杂质离子温度、密度和旋转速度。
1 实验原理电荷交换复合光谱诊断主要依赖于中性束注入等离子体后与离子发生电荷交换反应，使离子成为类氢原子；该类氢原子（离子）处于高能态的电子向低能态跃迁时辐射的光谱。
如下式所示：[H0b+An+→H+b+A（n-1）*+]式中：下标[b]代表中性束粒子；[A]指代等离子体中的杂质如碳、氧以及氦等。
谱线的强度和宽度是谱线的主要特性。
在等离子体中，存在许多因素使谱线发生展宽，主要包括自然展宽，多普勒展宽以及碰撞展宽等。
在高密度和低温的气体辐射条件下，多普勒展宽效应会不如碰撞展宽效应明显，谱线的线型近似为洛伦兹型；当辐射源处于低气压的辐射条件时，多普勒展宽比碰撞展宽和自然展宽会多两个数量级，因此谱线的线型近似为高斯型。
