A new detection method in studying penetration depth of low－energy heavy ions in botanic samples

1 INTRODUCTIONLow-energy heavy ion imPlantation has fOund its new application in crop breedingin recent years. It has been reported that the imPlantation of 20ro300 keV N+ ions intodry plant seeds such as rice and wheat in the dose ral1ge of 1015-1017 ions/cm' producedsignilicant inheritable mutation effe.t,[1]. The mutation effects axe guessed to be inducedby the direct interaction between energetic imPlanted ions and the DNA molecules in theembryo of seeds. However, based on the LS…     

A Preliminary Study on DNA Mutation Induction of Maize Pollen Implanted by Low Energy N+ Beam

1. IntroductionSo far, in China, low energy ion beam (LEIM) hasbeen used widely in plant and microbe-induced mutation breeding and transgene due to its bioeffectssuch as energy and mass deposition, charge exchangeof energetic ions and the energy absorption. Manystudies on mechanism of LIEM bioeffect and characteristics of DNA autogenesis were reported by usingsome materials in vitro including biondcromolecules,DNA and free radicals. UP to now) little is knownabout DNA macromolecules mu…     

Preliminary Studies on Base Substitutions and Repair of DNA Mismatch Damage Stimulated by Low Energy N＋ Ion Beam Implantation in Escherichia coli

Ever since the low energy N+ ion beam has been accepted that the mutation effects of ionizing radiation are attributed mainly to direct or indirect damage to DNA. Evidences based on naked DNA irradiation in support of a mutation spectrum appears to be consistent, but direct proof of such results in vivo are limited. Using mutS, dam and/or dcm defective Eschericha coli imitator strains, an preliminary experimental system on induction of in vivo mutation spectra of low energy N+ ion beam has been established in this study. It was observed that the mutation rates of rifampicin resistance induced by N+ implantation were quite high, ranging from 9.2×10-8 to 4.9 ×10~5 at the dosage of 5.2 ×1014 ions/cm2. Strains all had more than 90-fold higher mutation rate than its spontaneous mutation rate determined by this method. It reveals that base substitutions involve in induction of mutation of low energy nitrogen ion beam implantation. The mutation rates of mutator strains were nearly 500-fold (GM2929), 400-fol     

Study of Mutagenic Effects of M_1 Generation of Maize Seeds Irradiated by Heavy Ions

In order to study M_1 biological effects induced by heavy ion irradiation on maize seeds, the embryosof dry maize seeds are irradiated with ~7Li and ~(12)C ions. The experiment is performed at the heavy ionscanning tube of the HI-13 tandem accelerator. The beam goes through a thickness of 25μm. Then themaize seeds are irradiated in the air uniformly. The linear energy transmission of ~7Li and ~(12)C are 120 and     

Penetration depth and concentrationdistribution for implanted heavy ions with low energies in plant seeds bySEM and EDS

The penetration depth and concentration distribution of implanted ions have been studied for low energy heavy ions implanted in the dry seeds of plant,such as peanut,mung bean,sunflower,wheat and radish seeds,etc.by SEM EDS.The results show that the maximum penetration depth is about 12μm for V^ with an energy 200keV implanted in cotyledon of the peanut,18μm,15μm,20μm for V^2 with 90keV implanted in sunflower,wheat,radish seeds,respectively.The penetration depth of implanted Cu^2 with 80keV is about 90μm in the remainder funicle derivative of the mung bean seeds.The experimental result of the maximum penetration depth of implanted V^ in the peanut seeds was compared with the calculated value of the TRIM95.     

Overview of Research and Technology of Radiation Mutation Breeding in CIAE

<正>Ion beam radiation mutation breeding is a research field with independent intellectual property rights pioneered by Chinese scientists in the1980s.It has the advantages of small physiological damage,high mutation rate and wide mutation range,and has been widely used in a variety of crops.The HI-13 tandem accelerator of the Chinese Institute of Atomic Energy can provide ions with suitable energy,range and LET forradiation mutation breeding research.Institute of Crop Science,Chinese Academy of Agricultural Sciences and other units in radiation mutation breeding has cooperated for many years.     

Characteristics of Ions Emitted from Laser-Induced Silver Plasma

In this work, study of laser-induced ions is presented. The plasma was produced by focusing a Nd：YAG laser, with a wavelength of 1064 nm, a pulsed width of 9-14 ns, a power of 1.1 MW and energy of 10 mJ, on silver target in vacuum （10-3 Torr= 1.3332 Pa）. The characteristics of ion streams were investigated by CR-39 detectors located at angles of 0°, 30°, 60° and 90° with respect to normal of the target. The distance between the silver target and each detector was 11 cm. The energy of silver ions was found ranging from 1.5 eV to 1.06E4 eV. There was a high concentration of ions with low energy as compared to those with high energy, showing the energy distribution amongst the ions. The flux of ions was maximum in the axial direction which was decreasing with the angle increase with respect to normal of the target, and finally became minimum in the radial direction. Hence the silver ions have shown anisotropic behaviour.     

THINDOWN IN LITHIUM FLUORIDE (TLD—100)

A track structure model has been applied to calculate the relative thermoluminescent efficiency of TLD- 100 irradiated with energetic heavy ions. In earlier work we proposed that the response of TLD- 100 to γ-ray arises from a combination of 1- hit and 2- hit trap structures. The supralinear (2- hit) response is now known to diminish with a decrease in the energy of incident electrons. Since the delta rays of slow particles are of low energy, diminishing with a reduction in ion speed, we calculate the response to slow heavy ions by track theory as due to the 1- hit targets alone and obtain good agreement between theory and experiment. The branching of the experimental curves is principally caused by the kinematic limit in delta ray production for ions approaching the end of their range, an effect which is called "thidown" when seen in the tracks of heavy ions approaching the end of their range in electron sensitive nuclear emulsion.     

Effect of Ar Ion Beam Implantation on Morphological and Physiological Characteristics of Liquorice （Glycyrrhiza uralensis Fisch） Under Short-Term Artificial Drought Conditions

Ar^＋ ion beam with low energy of 30 keV was implanted into liquorice （Glycyrrhiza uralensis Fisch） seeds at the doses of 0, 600, 900 and 1200 × （2.6 × 10^13） ions/cm^2, respectively. The seeds were sowed in pots and after one month the plants were subjected to different drought conditions for two months. Then the plants＇ morphological and physiological characteristics, antioxidation enzymes and levels of endogenous hormones were investigated. The results showed that ion implantation at a proper dose can greatly enhance the liquorice seedlings＇ resistance against drought stress.     

Cellular and molecular studies of mutation induction by low energy heavy ions

Mutation induction by low energy heavy ions was scored at the hypoxanthine guanine phosphoribosyl transferase(HGPRT) locus using both normal human fibroblasts and the human-hamster hybrid AL cells.In addition,the mutation yield at a non-essential chromosome was also examined by using the S1 marker gene locating on human chromosome 11 in AL cells,Mutagenicity induced by low energy heavy ions was dose and LET dependent.THe induced mutant fractions at the S1 locus were consistently higher than those for HGPRT.Using a mutation system that can detect multilocus changes,it can be shown by either Southern blotting or multiplex PCR techniques that radiation can induce chromosomal deletions in the millions of basepairs.     

Phase changes of the ZrO2—12wt%Y2O3 film with Ar^＋ irradiation

1IntroductionYttrisistabilizedzirconiawithahighresistivityandalargerelativedielectricconstant.isaveryattractiveelectricalinsulator.11]Itcanbeusedforthefabricationofsilicon-oninsulator(SOI)structuresorasthebufferlayerinhighToceramicsuperconductorsonSttoavoidthereactionbetweenStandthesuperconductorfilm.[2]Thepolymorphicbehaviourofzirconiabasedceramicscontaininglessthan20wt%Yaosstillaffectsitsthermalshock-resistancewhenitisusedoveralargetemperaturerange.Ithasbeenfoundthatthereseemsacorrelesnon…     

Energy and flux measurements of laser-induced silver plasma ions by using Faraday cup

Silver(Ag)plasma has been generated by employing Nd∶YAG laser(532 nm,6 ns)laser irradiation.The energy and flux of ions have been evaluated by using Faraday cup(FC)using time of flight(TOF)measurements.The dual peak signals of fast and slow Ag plasma ions have been identified.Both energy and flux of fast and slow ions tend to increase with increasing irradiance from 7 GW cm-2 to 17.9 GW cm-2 at all distances of FC from the target surface.Similarly a decreasing trend of energies and flux of ions has been observed with increasing distance of FC from the target.The maximum value of flux of the fast component is 21.2×1010cm-2,whereas for slow ions the maximum energy and flux values are 8.8 keV,8.2×1012 cm-2 respectively.For the analysis of plume expansion dynamics,the angular distribution of ion flux measurement has also been performed.The overall analysis of both spatial and angular distributions of Ag ions revealed that the maximum flux of Ag plasma ions has been observed at an optimal angle of～15°.In order to confirm the ion acceleration by ambipolar field,the self-generated electric field(SGEF)measurements have also been performed by electric probe;these SGEF measurements tend to increase by increasing laser irradiance.The maximum value of 232 V m-1 has been obtained at a maximum laser irradiance of 17.9 GW cm-2.     

Effects of nitrogen ion irradiation on endoglucanase activity and gene mutation of Bacillus subtilis Bac01

Bacillus subtilis Bac01 was mutated by 15 keV N+ ions of 1.5×1016 cm-2.The mutant strain Bacll with high yield of endoglucanase was isolated using carboxymethylcellulose sodium and congo red indicative plates.It exhibited higher endoglucanase activitiy (381.89IU) than the original strain Bac01 (93.33IU).Two 1,500 bp endoglucanase gene fragments were obtained with PCR amplification from B.subtilis Bac01 and mutant strain Bac11.BLAST comparison result indicated that 10 nucleotides mutated.Bioinformatics methods were used to analyze the two predicted amino acid sequences,and it was found that 5 amino acid residues changed,being all in the cellulose-binding domain of endoglucanase.     

Fluorine ion transmission through thin biological samples

F^2 beam with 3MeV is used to irradiate thin biological samples(onion inner suface membrane and kidney bean coat)in the transmission measurement ,its current density is 400-800nA/cm^2,Results show that the onion samples can be broken up quickly under ion irradiating;as to kidney bean samples,about 60% of the implanted ions penetrate the samples,most of them lose part of their eneregy,fewer ions are found to be able to transmit through the sample without energy loss.SEM experiments are carried out to study sample‘s damage induced by the ions irradiation.     

强脉冲离子注入中的脉冲能量效应研究

在脉冲离子束流密度为15120A/cm2、脉宽为50150ns、加速电压为150260kV范围内，在11014cm-2的低注量水平上， 研究了高功率Cn++H+混合离子束注入45号钢样品的强脉冲能量效应。摩擦磨损和微观硬度测量以及SEM和X射线衍射分析表明，上述低注量强脉冲离子束注入可以改变材料 表面的微观结构和力学特性，而且强烈依赖于单个脉冲离子束的功率密度和能量密度。在相同离子注量条件下，普通C++H+离子注入对45号钢样品表面微硬度和摩擦系数未 见明显影响。直接证明了强脉冲能量效应在离子注入中是相对独立于注入元素掺杂效应的又一可利用的重要效应。基于一维导热模型，讨论了强脉冲能量效应以及脉冲离 子束功率密度对离子束材料表面改性的作用。     

PIXE、SEM与切片技术相结合研究低能离子注入种子的浓度-深度分布

用质子激发X荧光分析和扫描电子显微镜与切片技术相结合对能量为 2 0 0keV的钒离子注入花生后的浓度 -深度分布进行了测定 ,注入剂量为 9× 10 16/cm2 。结果显示 ,钒离子注入花生后的浓度 -深度分布与离子注入金属、半导体中的分布有明显的差异 :离子的射程歧离很大 ,少数离子的射程延伸到很深的区域。这种分布特征可能与植物种子具有疏松的结构有关。     

Pb离子辐照注碳a-SiO2薄膜的光致发光性能

用湿氧化法在单晶硅表面生长了非晶态SiO2薄膜,进行120 keV C离子注入和950 MeV Pb离子辐照,用荧光光谱分析样品发光特性的改变.结果发现,C离子注入和高能Pb离子辐照均能显著影响样品的发光特性,且荧光光谱的改变强烈依赖于注入和辐照剂量,预示不同注入和辐照剂量将导致不同的发光结构形成.对注入和辐照造成薄膜...     

氮离子束注入诱变选育胞外多糖高产菌株

采用氮离子束注入胞外多糖产生菌进行诱变处理来获得胞外多糖高产菌株。氮离子注入过程采用的能量为10 keV,剂量为60×1014–140×1014cm-2。根据其存活率及突变率确定最佳的注入剂量。结果表明:菌株存活率曲线遵循氮离子注入生物效应的"马鞍型曲线",当注入剂量为120×1014cm-2时,获得了最佳的诱变效果。通过筛选和连续5次传代,获得具有良好稳定性的突变株,其多糖产量达到3.29 g/L,较出发菌株提高了19.20%,且发酵周期缩短了6 h。     

Effects of energetic heavy ion irradiation on the structure and magnetic properties of FeRh thin films

Fe-54at.%Rh thin films were irradiated with 10 MeV iodine ions at room temperature. Before and after the irradiations, the changes in magnetic properties and the lattice structure of the samples were studied by means of a SQUID magnetometer and X-ray diffraction. For the low fluence irradiation, the SQUID measurement at 20 K shows that the anti-ferromagnetic region of the thin film is changed into ferromagnetic region by the irradiation. As the film thickness is much smaller than the ion range, we can discuss the relationship between the density of energy deposited by ions and the change in magnetization quantitatively. For the high fluence irradiation, the magnetization of the film is strongly decreased by the irradiation, which can be explained as due to the change in lattice structure from B2 into A1 structure by the irradiation.