用于高能微焦点工业CT的旋转式辐射转换靶研究

转换效率高、散热性能优异的辐射转换靶是高能微焦点工业CT的关键部件,本文设计了一种适用于高能（6 MeV）微焦点(直径约100 μm)工业CT的先进旋转式辐射转换靶。通过模拟分析辐射转换靶X射线转换效率和热沉积,确定最优转换靶厚度,从而设计、加工出旋转式辐射转化靶,并成功应用于中国工程物理研究院应用电子学研究所高能微焦点工业CT验证装置。对比实验结果显示,在相同工况（电子束能量6 MeV,宏脉冲长度5 ms,宏脉冲流强15 mA,焦斑直径100 μm）下,固定靶被电子束熔融,而旋转靶则能够承受电子束的轰击,验证了旋转式辐射转换靶的有效性和可靠性。     

低剂量X射线和低浓度MMC、H2O2、CP诱导人血淋巴细胞、小鼠骨髓细胞和生殖细胞的交叉适应性反应

采用低剂量X射线（剂量10和50mGy，剂量率50mGy/min）和低浓度丝裂霉素C（MitomycinC,MMC)、过氧化氢（Hydrogen peroxide,H2O2）、环磷酰胺（Cyclophoshamide,CP）交叉作用，观察了它们诱导的离体人血淋巴细胞、整体小鼠骨髓细胞和生殖细胞染色体畸变，以探讨辐射与化学物质之间的交叉适应性反应。结果表明：（1）预先给予10mGy的X射线照射，3h后予以不同浓度的MMC（0．5、2．5、5．0mg/kg），可诱导小鼠骨髓细胞染色体畸变的交叉适应性反应；（2）预先给予50mGy的X射线照射，3h后邓以不同浓度的MMC、H2O2、CP，其中，辐射与MMC和H2O2之间可诱导小鼠生殖细胞染色体畸变的交叉适应性反应，而辐射与CP之间未观察到交叉适应性反应，二者有协同作用；（3）预先给予MMC（终浓度为35ng/mL）处理，6h后给予1．5GyX射线照射，可诱导人血淋巴细胞染色体畸变的交叉适应性反应；（4）预先给予低浓度MMC、H2O2和CP处理，24h后给予1．5Gy射线照射，低浓度MMC和H2O2可以诱导抗X射线损伤的交叉适应性反应，而低浓度的CP不能诱导抗X射线损伤的交叉适应性反应，二者具有协同作用。提示X射线与MMC之间的交叉适应性反应不仅存在于整体的小鼠骨髓细胞中，而且在离体人外周血淋巴细胞中也可以诱生；低剂量X射线与低浓度MMC和H2O2之间的交叉适应性反应在整体的小鼠生殖细胞中可以互相诱导，但是，低剂量X射线与低浓度CP在整体的小鼠生殖细胞中未诱导出交叉适应性反应，二者有协同作用。     

用CB微核法研究离体血辐射剂量与微核率的量效关系

应用胞质分裂阻滞微核技术（简称CB微核法），探讨了X射线与60Coγ射线，以及不同剂量率的60Coγ射线诱发微核率与辐射剂量的量效关系。结果表明，剂量率相同，照射剂量相同，60Coγ射线辐照所得微核频率明显高于X射线照射所得微核频率。不同剂量率的60Coγ射线照射，高剂量率所得微核产率高。剂量效应曲线不仅与不同的辐射种类有关，而且同一种性质的射线在不同剂量率情况下，刻度曲线不一样，因而应选用不同剂量率作刻度曲线。在发生辐射事故时，应选用剂量率刻度曲线接近的一种。     

用于高能微焦点工业CT的旋转式辐射转换靶研究

转换效率高、散热性能优异的辐射转换靶是高能微焦点工业CT的关键部件,本文设计了一种适用于高能(6 MeV)微焦点(直径约100μm)工业CT的先进旋转式辐射转换靶。通过模拟分析辐射转换靶X射线转换效率和热沉积,确定最优转换靶厚度,从而设计、加工出旋转式辐射转化靶,并成功应用于中国工程物理研究院应用电子学研究所高能微焦点工业CT验证装置。对比实验结果显示,在相同工况(电子束能量6 MeV,宏脉冲长度5 ms,宏脉冲流强1.5 mA,焦斑直径100μm)下,固定靶被电子束熔融,而旋转靶则能够承受电子束的轰击,验证了旋转式辐射转换靶的有效性和可靠性。     

聚变堆第一壁C SiC涂层微观结构研究

用光学显微镜(OM)、扫描电镜(SEM)、X射线衍射仪(XRD)、X射线波谱仪(WDS)和能谱仪(EDAX),观察研究了C_3H_6-CH_3SiCl_3-Ar混合气体在石墨基体上化学气相沉积(CVD)的C SiC涂层的显微组织、晶体结构、SiC含量及分布与制备工艺的关系,以及氢离子(H~ )化学溅射和高能电子束热冲击对C SiC涂层微观结构和性能的影响。研究结果表明,在1600℃下制备的C SiC涂层,具有良好的结合强度、抗化学溅射和抗热冲击性能。     

2MeV加速器辐射防护的设计

高能电子束在工业生产和社会中的应用越来越多。由于它与物质的作用会产生大量X射线，对人体会造成辐射损伤，必须对其进行一定的屏蔽。出于节省成本和材料，减轻防护质量的目的，必须对防护进行优化设计。本工作首先用蒙特卡罗程序计算了沿束流方向不同屏蔽材料后的辐射剂量，并与经验公式的计算结果进行比较，从而确定了所需要的屏蔽材料厚度。     

橡胶辐射硫化

橡胶辐射硫化是在高能射线(钴源产生的γ射线或电子加速器产生的高能电子束)辐照下产生交联的过程。由于不需要添加硫化剂及在常温、常压下硫化,因此,具有产品纯度高、工艺简单及节省能源的明显优点。     

批制辐射加工用辐射变色薄膜剂量性能研究

以尼龙为基材、副品红氰化物为染料制备了辐射变色薄膜剂量计,并在⁶⁰Co γ射线及10 MeV电子束参考辐射场中对辐射变色薄膜的各剂量学响应性能进行了研究。研究结果表明,在1~210 kGy剂量范围内,该辐射变色薄膜剂量计具有较好的剂量响应线性,且在本实验范围内未发现明显的能量和剂量率依赖性;该剂量计重复性好于1.0%,照射后置于低温条件下贮存2周内信号较稳定;在1~210 kGy剂量线性范围内得到的辐射变色薄膜剂量计测量吸收剂量的扩展不确定度对⁶⁰Co γ射线为4.4%（k=2）,对电子束为6.2%（k=2）。通过在加速器上进一步的实验表明,该辐射变色薄膜除可用于辐射加工中剂量监测外,还可用于电子束辐照参数的测量。     

γ射线辐照后木荷粉自由基的ESR和XPS分析

利用电子自旋共振波谱（ESR）和X射线光电子能谱（XPS）技术分别测量γ射线辐照后木荷粉体的自由基波谱和X射线光电子能谱。分析木荷粉体在60Coγ射线辐照下自由基的变化规律、化学组成和结构变化。结果表明：木荷自由基的光谱分裂因子g=2．0033,自由基的强度随吸收剂量按指数规律,I=1-e40增加;经过200kGy剂量的辐照后木荷表面O／C原子比稍有增加,C—C、C—H和C-O键含量增加,C=O双键含量减少,-O—C=O含量增加为原来的2．5倍,说明木材表面生成了一些含氧官能团,或碳的氧化态增高。     

在酚醛/乙醇溶液中利用γ射线共辐照改性碳纤维表面性能的研究

辐射加工技术以其高效、节能和环保等特点,在改性材料界面上已经得到广泛应用。本文利用γ射线共辐照接枝技术,在酚醛／乙醇溶液中对碳纤维表面进行处理。对辐照处理前后的碳纤维,分别利用X射线光电子能谱定性和定量分析表面化学元素及官能团组成;原子力显微镜观察碳纤维单丝表面形貌的变化;用扫描电子显微镜观察碳纤维表面复合材料层间剪切断口;通过层间剪切强度表征碳纤维增强环氧树脂复合材料的界面性能,并在30kGy吸收剂量下(剂量率4．8kGy／h),比较了不同浓度的接枝液对层间剪切强度的影响。结果表明,γ射线引发酚醛能够在碳纤维表面发生接枝反应,处理后碳纤维表面形貌有明显变化,能够有效地增加碳纤维表面O／C值和含氧官能团数量,提高其复合材料的界面强度。     

双酚A型聚砜X射线致发降解的X射线光电子能谱研究

利用X射线光电子能谱(XPS)研究了双酚A型聚砜薄膜在超高真空下X射线辐照所引起的表面化学组成变化。结果表明:(1)聚砜在X射线辐照下,部分砜基团变成了硫化物。(2)硫化物的生成量取决于辐照时间。(3)在XPS的取样深度里,同一辐照时间下,X射线致发降解的程度基本上是均匀的。     

CO对金属铀表面氧化层影响研究

用Ｘ射线光电子能谱（ＸＰＳ）和气相色谱（ＧＣ）分析研究了ＣＯ对金属铀表面氧化层的影响。ＣＯ在表面氧化层上的吸附反应导致了Ｕ４ｆ峰向低结合能方向位移，氧化物中氧含量减少，原子比（Ｏ／Ｕ）比值下降了７．２％。体系中ＣＯ２体积分数增大１１．０％。研究结果表明，ＣＯ气氛可抑制金属铀表面的进一步氧化。     

Improvement of carbon fiber surface properties using electron beam irradiation

Carbon fiber-reinforced advance composites have been used for structural applications,mainly on account of their mechanical properties.The main factor for a good mechanical performance of carbon fiber-reinforced com- posite is the interfacial interaction between its components,which are carbon fiber and polymeric matrix.The aim of this study is to improve the surface properties of the carbon fiber using ionizing radiation from an electron beam to obtain better adhesion properties in the resultant composite.EB radiation was applied on the carbon fiber itself before preparing test specimens for the mechanical tests.Experimental results showed that EB irradiation improved the ten- sile strength of carbon fiber samples.The maximum value in tensile strength was reached using doses of about 250 kGy.After breakage,the morphology aspect of the tensile specimens prepared with irradiated and non-irradiated car- bon fibers were evaluated.SEM micrographs showed modifications on the carbon fiber surface.     

O钝化对铀铌合金电化学腐蚀行为的影响

采用电化学方法研究了铀铌合金经CO（0.3MPa)钝化前后的电化学耐蚀性能,并用X射线光电子能谱（XPS）分析了铀铌合金经CO钝化后表面层的组成。研究结果表明：铀铌合金经CO钝化后表面生成了致密的钝化膜,这层钝化膜增大了腐蚀过程的阳极阻力,提高了铀铌合金的电化学耐蚀性能。     

卤化铜对尼龙610辐射效应的影响

在尼龙６１０中加入卤化铜,用Ｘ射线衍射法和ＤＳＣ研究尼龙６１０结晶度的变化,并进行电子束辐照。结果表明：卤化铜能有效提高尼龙６１０的辐射交联效率。     

EB预辐照对制备PANACF表面形貌的影响

提出了利用电子束（electron beam, EB）预辐照聚丙烯腈基纤维（polyacrylonitrile-based fiber, PANF）后再进行炭化活化制备聚丙烯腈基活性炭纤维（polyacrylonitrile-based activated carbon fiber, PANACF）的方法。吸收剂量为160 kGy并用w=10%KOH溶液浸渍30 min的PANF在450 ℃下模拟炭化活化30 min后,SEM分析显示其表面出现了与未辐照PANF不同的密集的蜂巢状结构,其BET法比表面积（specific surface area, SSA）约为未辐照样品的9倍,BJH法计算结果显示其为孔径分布集中在2～10 nm的介孔材料。该结果表明,EB预辐照对制备PANACF的表面形貌具有调控作用。     

The morphology and structure of one-dimensional carbon-carbon composite under high-fluence ion irradiation

The temperature dependences of the ion-induced electron emission yield γ(T), the crystal structure, and the morphology of a surface layer of the one-dimensional carbon fiber composite KUP-VM (1D) under high-fluence (10¹⁸-10¹⁹ ion/cm²) irradiation with 30 keV ions at normal incidence both perpendicular and parallel to the fiber directions have been studied. The target temperature has been varied during continuous irradiation from T = −180 to 400 °C. The surface analysis has been performed by the RHEED, SEM and RBS techniques. The surface microgeometry was studied using laser goniophotometry (LGP). It has been found that ion irradiation results in a loss of anisotropy of the surface layer structure because of amorphization at room temperature or recrystallization at a temperature higher than the ion-induced annealing temperature. The fiber morphology anisotropy remains under ion irradiation.     

Electron beam modification and functionalization of MWNT for covalent dispersion into polymeric systems

The development of nanotube-based polymer composites with improved mechanical properties and electrical conductivity requires the covalent dispersion of carbon nanotubes to utilize their stress transfer capabilities. Covalent dispersion of nanotubes therefore requires the functionalization of their surface to interact with solvents or monomers. In this work, we have developed a novel method of nanotube surface modification in which dry MWNT are irradiated with a high-energy electron beam (EB) in ambient air environment. Raman spectroscopy was performed to characterize the influence of EB irradiation on nanotubes, namely, variance of the disorder, or D band (∼1360 cm⁻¹) with respect to the graphitic, or G, band (∼1580 cm⁻¹). Raman spectra show increased deformation to the graphitic structure, as well as increased strain on the carbon-carbon bonds, weakening the nanotube. Transmission electron microscopy (TEM) confirms that nanotubes remain intact despite high EB dose. In addition, minimal surface deformation and length reduction occurred on irradiated MWNT.     

Heavy ion beam induced phenomena in polytetrafluoroethylene

This paper describes the results on thermal and chemical analysis of polytetrafluoroethylene (PTFE) film stack after high-energy heavy ion beam irradiation under atmospheric fields at room temperature. After high-energy C⁶⁺ ion beam irradiation, the PTFE film stack was separated one by one, and then the various measurements such as differential scanning calorimetric (DSC) analysis and solid-state ¹⁹F magic-angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy were performed to get information of the chemical reaction and structural change at the localized positions. By ion beam irradiation for PTFE at room temperature, it is suggested that the abnormal phenomena due to the change of morphology could be observed by DSC analysis. In the solid-state ¹⁹F-MAS-NMR spectroscopy of ion irradiated PTFE film including Bragg peak region, several new signals were observed besides the intense peak of -CF₂- at −124 ppm. The detected new signals in ion irradiated PTFE should be due to the changed chemical structures. The signals, which are assigned, to the tertiary carbon group with branching site (Y-type crosslinking site), perfluoro-propylene site and chain end methyl site were directly detected, though it was under the oxidation condition. Thus, although it was under the oxidation condition, the branching or crosslinking reaction was taken place with the chain scission in the matrix. Moreover, the branched chain length would become short, compared with EB-crosslinked PTFE. Hence, it could be suggested that the irradiation of heavy ion beam induced large amounts of intermediate species, compared with EB or γ-ray irradiation, and then, those would be reacted with each other in the localized area. Especially, in region of the Bragg peak, the ion beam induced more large amounts of intermediate species than in the other region.