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采用自电子湮没寿命测量方法研究了注量为6.5×10^15/cm^2和1.4×10^14/cm^2,En≥1MeV的裂变中子辐照在掺Si,N型单晶GaAs产物的缺陷,此辐照在GaAs中产生单空位和双空位缺限,缺陷浓度于比于辐照注量,高温退火产生三空位缺陷及小空位团,单空位,双空位和三空位缺陷的退火温度分别为250,450,650℃。 相似文献
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在本征型GaAs中注入2.0MeV(剂量1.0×10^15/cm^2)+2.9MeV(剂量1.1×10^15/cm^2)的^16O,使氧在约1.5-2.5μm之间形成均匀分布。注入样品分别经400-800℃、15min热退火后的电阻率测量表明,经500℃和600℃退火后的样品具有高的电阻率(~10^8Ω·cm);而当退火温度进一步升高时,其电阻率逐渐下降,并具有p型导电行为。沟道RBS分析表明,当 相似文献
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报道了在En=14.5-14.9MeV中子能区用活化法以^27Al(n,a)^14Na的反应截面为中子注量标准测得的^154Sm(n,2n)^153Sm和^148Sm(n,p)^148gPm反应截面,并将其与已有的数据进行了比较,中子能量用铌锆截面比法测定。 相似文献
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采用正电子湮没技术研究3×10^20/cm^2中子注量,En≥1MeV快中子辐照在α-Al2O3中产生的辐照效应,实验发现α-Al2O3在辐照后的850℃退火形成尺寸约为0.7nm的空洞。 相似文献
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本文应用Al为阈探测器在兰州重离子研究装置(HIRFL)的辐照终端上研究了75MeV/u12C离子束在辐射生物实验区产生的能量大于6MeV的中子角分布。实验中束流经24μm的Ni窗及由10μm镀金的Mylar膜组成的平行板电离室后进入实验区,7个20mm×5mm的阈探测器放置在距Ni窗25cm处的不同角度上(6.5°~36.0°),束流强度为3nA,活化样品测量用高纯锗探测器。结果表明,实验区产生的中子具有明显的前冲分布,测得的中子注量率分布,在与束流方向夹角6.5°~36.0°范围内,大致呈指数衰减。这为进一步开展的重离子治癌研究提供了辐射防护的实验依据。 相似文献
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在热中子与快中子成份比大于70的条件下,用6.5×1016cm-2和6.5×1018cm-2剂量水平辐照纯净GaAs样品,研究由于嬗变产生的杂质和损伤。所得结果表明:热中子对Ga、As发生俘获核反应,其最终稳定产物Ge作为两性杂质元素被导入;复杂的移位缺陷形成及其热行为是影响辐照后GaAs电学性质变化的重要因素。 相似文献
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用兰州重离子研究装置(HIRFL)首次进行了47MeV/u的C^6^+离子辐照CaVSn:YIG的实验。通过穆斯堡尔效应和正电子寿命测量对47MeV/u的C^6^+离子在CaVSn:YIG中的辐照效应进行了初步研究。发现辐照导致内磁场方向趋于各向同性分布,由穆斯堡尔谱未观察到非晶化现象。缺陷的数量随C^6^+离子在样品中电子能量损失的增加而增加。 相似文献
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《中国原子能科学研究院年报》2018,(0)
正A 3 MeV/6 MeV Electron Linear Accelerator(Linac)developed independently by CIAE was exported overseas on 14 May,2018.The Linac used for Non Destructive Testing(NDT)is a dual energy(3 MeV/6 MeV)accelerator which can switch between 3 MeV and6 MeV in milliseconds.With widest energy band,it has been one of the most advanced accelerators 相似文献
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The irradiation damage structures produced in high-purity copper by a fluence of particles/cm2 of 16 MeV protons, 14 MeV neutrons, and fission neutrons () were studied by transmission electron microscopy. The damage consists of vacancy-and-interstitial clusters or sessile Frank dislocation loops oriented on {111} planes of the copper matrix, and ranges in size from 25 Å (lower limit of resolution) to 200Å in diameter. p]The size-density distributions of the clusters in the 14 MeV neutron and 16 MeV proton irradiated samples were virtually identical, and the average size of the clusters in these two groups of specimens was substantially larger than was the case for those in the fission-neutron-irradiated copper. 相似文献
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A. Denker K. H. Maier 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》1999,150(1-4):118-123
The elemental composition of realistic thick samples has been measured with PIXE by 68 MeV protons. Heavy elements can be well detected much deeper below the surface, than with other methods. Measurements on objets d'art are presented. Large and complicated objects can be measured easily. 相似文献
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J. Lalita N. Keskitalo A. Hall n C. Jagadish B. G. Svensson 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》1996,120(1-4):27-32
Lightly doped silicon samples of both n- and p-type have been implanted with low doses of H, B and Si ions using energies between 1 and 6 MeV. The resulting electrically active point defects were characterized by deep level transient spectroscopy (DLTS) and several of these defects involve oxygen and/or carbon, two major impurities in as-grown crystalline silicon. Both interstitial- and vacancy-type defects are observed; in particular, interstitial carbon is found to migrate at room temperature with a diffusion constant of 1 × 10−15 cm2 s−1 and is effectively trapped by interstitial oxygen atoms. The concentration of implantation-induced defects increases linearly with dose but the defect production decreases at high enough dose rates. This dose rate effect depends on the ion mass and is qualitatively predicted by computer simulations of the defect reaction kinetics. 相似文献
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Yu. N. Grigor'ev I. S. Grishaev A. N. Dovbnya A. S. Zelencher O. G. Il'in I. N. Kova V. P. Kozin S. G. Kononenko N. I. Mocheshnikov A. A. Rakityanskii L. V. Reprintsev A. S. Tarasenko V. A. Terekhov V. D. Tkachenko A. E. Tolstoi S. D. Fainzil'berg A. M. Shenderovich 《Atomic Energy》1967,23(6):1301-1306
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《Journal of Nuclear Science and Technology》2013,50(11):838-846
A cooling system of a stationary target for the Fusion Neutronics Source (FNS) has been designed to satisfy the structural, thermal and hydraulic requirements. Two square tubes for ion beam and for cooling water were concentrically placed and the target was mounted on the top of the beam guide tube. The end plate of the outer tube was devised to be removable for easier replacement of the target. In order to test the cooling capability of the system, dummy target assemblies with electical heaters were used in the experiment of heat transfer in place of using an accelerator. Correlations of heat transfer and head loss were obtained experimentally as a function of Reynolds number. The extrapolation of the data has shown that for the present target system, about 2.3 kW is the maximum power for the beam in diameter of 15 mm. This value was sufficiently large compared with the required heat load of FNS. 相似文献
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《中国原子能科学研究院年报》2018,(0)
正Iron is a widely used material in nuclear reactor.Neutron inelastic scattering is an important energy loss mechanism.Its precision affects reactor calculations and radiation shielding design.1.2 MeV and 2.5 MeV neutrons were produced 相似文献