铒离子注入碳化硅的射程和退火行为研究

用300—500 keV能量的铒(Er)离子注入碳化硅(6H-SiC)晶体中,利用卢瑟福背散射技术研究了剂量为5×10¹⁵ cm^-2 的Er离子注入6H-SiC晶体的平均投影射程R_p和射程离散ΔR_p,将测出的实验值和TRIM软件得到的理论模拟值进行了比较,发现R_p的实验值与理论值符合较好,ΔR_p的实验值和理论值差别大一些 关键词： 离子注入 投影射程和射程离散 退火行为 卢瑟福背散射技术     

Effective Parameters on Energy Losses of Fast Electron in Fusion Mediums

The stopping and scattering of fast electrons in a dense plasma relevant to inertial confinement fusion (ICF) are investigated numerically with the latest improved cross section equations. Binary and collective effects are considered to determine beam transport parameters such as range, penetration depth, spreading processes as straggling and blooming versus electron energy and plasma parameters. Blooming and straggling effects, which act as consequences of scattering with statistical assumption in collisions, lead to a non-uniform, extended region of energy deposition. Finally the mean angle of deflections is calculated for different plasma energies.     

热电子与聚变等离子体相互作用模拟计算的误差分析

对惯性约束聚变(ICF)实验条件下热电子辐照聚变等离子体（DD,DT）的射程岐离和散射进行了分析。结果表明,射程岐离和散射随射程增加近似呈直线增加;射程岐离和散射大小与等离子质量有一定关系。在单能热电子入射下,散射是计算结果误差的主要来源,误差在5%以下,绝对数在数十MA。入射束流的电子完全沉积在热斑中的聚焦角度,在边沿点火方式中,氘等离子体中为20.64,氘氚等离子体中为21.8;在中心加热方式中,氘等离子体中为16.36,氘氚等离子体中为17.6,在技术上相对易于实现。     

MeV能量离子在生物样品中的能量损失与能量离散

为了研究 MeV能量离子在生物样品中的能量损失与能量离散, 分别使用1.0, 1.8和2.8 MeV质子和4.5 MeV氦离子分别辐照不同质量厚度的洋葱内表皮膜。 当质子穿过该生物样品后, 可以利用透射能谱测量透射离子的能量损失和能量离散。 实验结果显示, 在以上的生物样品中, MeV能量离子的能量损失值和TRIM程序模拟的结果相吻合, 但是透射离子的能量离散值却与TRIM程序模拟结果有很大的不同。 结合生物样品的结构不均匀的特性, 对Bohr能量离散理论进行了修正, 并发现修正后的Bohr能量离散理论计算结果与实验值符合得很好。     

Ranges of 0.2-1.0 GeV/nucleon heavy ions in nuclear photoemulsion

Heavy nuclei transport in matter are studied experimentally and theoretically. Our experimental range and straggling values of 0.2 – 1.0 GeV/nucleon ²⁰Ne, ⁴⁰Ar, ⁵⁶Fe, ¹⁹⁷Au and ²³⁸U nuclei in BR-2 nuclear photoemulsion are presented and compared with model calculations carried out according to our RANGE-program and the PRAL-model (version of 1987) developed by Ziegler et al. The presented data analysis points at the necessity to take into account Z³-correction in Bete-Bloch formula when ionization losses of very heavy multicharge ions (for example ¹⁹⁷Au and ²³⁸U) are calculated. The comparison of experimental and calculated results showed that RANGE program can correctly calculate the ranges and straggling of heavy ions. The difference between experimental and theoretical data do not exceed 5% in all of the cases examined. PRAL model describes the heavy ion ranges quite adequately, but overestimates the particle range straggling.     

Energy Straggling Calculations Under IPM Potential

By using Bonderup and Hvelplund's formulation the energy straggling for light ions (such as H~+, He~(+2)) etc) in each element has been calculated based on the IPM potential. The results obtained in this paper not only reveal a Z_2 oscillation and energy dependence) but also give a single parameter IPM electron density function n(r) which is fitted by Hartree-Fock (HF) model. Merover, we suggest a very simple theory method for calculating energy straggling of a compound of a mixing matter with mean atomic number Z_2~* and adjustable parameter d~* except additivity rule, the results are in good agreement with recent experiments.     

中能重离子束深度剂量分布计算

提出了称之为复合歧离算法的中能重离子束深度剂量分布计算方法,并计算了中能C,O离子束的Bragg相对剂量分布曲线,同实验测量结果进行了比较,计算与实验测量符合得很好.证实了复合歧离算法的合理性及由它计算Bragg曲线的可靠性.补充和完善了离子束的深度剂量分布计算原理与方法.     

30 keV to 2 MeV Boron implantation profiles in solids

Abstract

Boron was implanted into several solids in the dose regime 10¹⁴ to 10¹⁶ ions/cm² and at energies between some 10 keV and some MeV. Measurements of the corresponding depth distributions were performed by means of the ¹⁰B(n, α₀)⁷Li(gnd) and ¹⁰B(n, α₁)⁷Li?(1st) nuclear reaction techniques with thermal neutrons, and by SIMS. The results are compared to theoretical predictions.     

空间高能离子在纳米级SOI SRAM中引起的单粒子翻转特性及物理机理研究

基于蒙特卡罗方法研究空间高能离子在65—32 nm绝缘体上硅静态随机存取存储器(SOI SRAM)中产生的灵敏区沉积能量谱、单粒子翻转截面和空间错误率特性及内在的物理机理.结果表明:单核能为200 MeV/n的空间离子在60—40 nm厚的灵敏区中产生的能损歧离导致纳米级SOI SRAM在亚线性能量转移阈值区域出现单粒子翻转;宽的二次电子分布导致灵敏区仅能部分收集单个高能离子径迹中的电子-空穴对,致使灵敏区最大和平均沉积能量各下降25%和33.3%,进而引起单粒子翻转概率降低,以及在轨错误率下降约80%.发现俘获带质子直接电离作用导致65 nm SOI SRAM的在轨错误率增大一到两个数量级.     

Deuteron induced damage in alkali halides

Abstract

The thermoelectric and galvanomagnetic properties in the CdxHg1_xTe solid solution samples (x = 0.12; 0.15) irradiated at 300 K by electrons (3.5 MeV; by integrated fluxes up to 1.46 × 10¹⁸e/cm²) have been investigated in a wide temperature range 4.2–300 K and in magnetic fields 0–22 kOe.

It has been discovered that the electron irradiation of Cd_xHg_1–xTe crystals leads to an increase of the Hall coefficient and a decrease of the thermo e.m.f. sign inversion temperature. The concentrations and mobilities of electron and hole have been calculated on a basis of quantitative analysis of galvanomagnetic data. It has been shown that the kinetic coefficient behavior upon irradiation is due to the Te vacancy-based type radiation defect origin.