Kinetic energies of C-n(+) (n <= 58) fragment ions produced by nanosecond laser impact on C-60

Laser-induced fragmentation of C-60 has been studied using a time-of-flight mass spectrometric technique. The average kinetic energies of fragment ions C-n(+) (n <= 58) have been extracted from the measured full width at half maximum (FWHM) of ion beam profiles. The primary formation mechanism of small fragment ion C-n(+) (n < 30) is assumed to be a two-step fragmentation process: C60 sequential decay to unstable C-30(+) ion and the binary fission of C-30(+). Considering a second photo absorption process in the later part of laser pulse duration, good agreement is achieved between experiment and theoretical description of photoion formation. (C) 2009 Elsevier B. V. All rights reserved.

HIRFL-CSR complex

The construction and commissioning of HIRFL-CSR were finished in 2007. From 2000 to 2005 the subsystem and key devices of CSR were successfully fabricated, such as magnet, power supply, UHV system, e-cooler, electric-static deflector with the septum of 0.1 mm, and the fast-pulse kicker with the rise time of 150 ns. After that the CSR commissioning activities were performed in 2006 and 2007, including the accumulation of those heavy ions of C, Ar, Kr and Xe by the combination of stripping injection (STI) or multiple multi-turn injection (MMI) and e-cooling with a hollow e-beam, wide energy-range synchrotron ramping by changing the RF harmonic-number at mid-energy, the beam stacking in the experimental ring CSRe, the RIBs mass-measurement with the isochronous-mode in CSRe by using the time-of-flight method, and the ion beam slow-extraction from CSRm.

Assessment of DNA damage of Lewis lung carcinoma cells irradiated by carbon ions and X-rays using alkaline comet assay

DNA damage and cell reproductive death determined by alkaline comet and clonogenic survival assays were examined in Lewis lung carcinoma cells after exposure to 89.63 MeV/u carbon ion and 6 MV X-ray irradiations, respectively. Based on the survival data, Lewis lung carcinoma cells were verified to be more radiosensitive to the carbon ion beam than to the X-ray irradiation. The relative biological effectiveness (RBE) value, which was up to 1.77 at 10% survival level, showed that the DNA damage induced by the high-LET carbon ion beam was more remarkable than that induced by the low-LET X-ray irradiation. The dose response curves of '' Tail DNA (%)'' (TD) and "Olive tail moment" (OTM) for the carbon ion irradiation showed saturation beyond about 8 Gy. This behavior was not found in the X-ray curves. Additionally, the carbon ion beam produced a lower survival fraction at 2 Gy (SF2) value and a higher initial Olive tail moment 2 Gy (OTM2) than those for the X-ray irradiation. These results suggest that carbon ion beams having high-LET values produced more severe cell reproductive death and DNA damage in Lewis lung carcinoma cells in comparison with X-rays and comet assay might be an effective predictive test even combining with clonogenic assay to assess cellular radio sensitivity

Biomedical research with heavy ions at the IMP accelerators

The main ion-beam acceleration facilities and research activities at the Institute of Modern Physics (IMP), Chinese Academy of Sciences are briefly introduced. Some of the biomedical research with heavy ions such as heavy-ion biological effect, basic research related to heavy-ion cancer therapy and radiation breeding at the IMP accelerators are presented.

Preliminary results of the updated LECR2 source-LECR2M

The Latest developed LECR2M (Lanzhou ECR No. 2 Modified) source is the updated one of LECR2 (Lanzhou ECR No. 2) source at IMP. It has been assembled on the low energy ion beam experimental platform to produce MCI beams for atomic physics and material physics experimental research. In our updating program, the structure of injection and extraction components has been modified to make the source structure more simple and effective. The hexapole magnet has also been replaced by a new hexapole magnet with higher radial field and larger inner diameter. With this updating, stronger magnetic field confinement of the ECR plasma is possible and better base vacuum condition is also achieved. LECR2M was designed to be operated at 14.5GHz. During the preliminary test, 1.3emA O6+ beam was extracted with the injected rf power of 1.1kW. The source has been used to deliver intense MCI beams for different experiments. After some discussion of the main features of this newly updated source, some of the typical commissioning test results of LECR2M will be presented.

An online monitor ionization chamber used in particle therapy

The clinical trials of tumor therapy using heavy ions beam C-12 are now in progress at Institute of Modem Physics in Lanzhou. In order to achieve the precise radiotherapy with the high energy C-12 beam in active pencil beam scanning mode, we have developed an ionization chamber(IC) as an online monitor for beam intensity and also a dosimeter after calibration. Through the choosing of working gas and voltage, optimizing of the electrics and the read-out system, calibrating the linearity, the detector system provide us one of the simple and highly reliable way to monitoring the beam during the active pencil beam scanning treatments. The measurement results of this detector system show that it could work well under the condition of high energy C-12 beam in active pencil beam scanning mode.

Commissioning of electron cooling in CSRe

The 400 MeV/u C-12(6+) ion beam was successfully cooled by the intensive electron beam near 1 A in CSRe. The momentum cooling time was estimated near 15 s. The cooling force was measured in the cases of different electron beam profiles, and the different angles between the ion beam and electron beam. The lifetime of the ion beam in CSRe was over 80 h. The dispersion in the cooling section was confirmed as positive close to zero. The beam sizes before cooling and after cooling were measured by the moving screen. The beam diameter after cooling was about 1 mm. The bunch length was measured with the help of the signals from the beam position monitor. The diffusion was studied in the absence of the electron beam.

Some Superconducting Magnets at IMP

Some superconducting magnets research at IMP (Institute of Modern Physics, CAS, Lanzhou) will be described in this paper. Firstly, a superconducting electron cyclotron resonance ion source (SECRAL) was successfully built to produce intense beams of highly charged heavy ions for Heavy Ion Research Facility in Lanzhou (HIRFL). An innovation design of SECRAL is that the three axial solenoid coils are located inside of a sextupole bore in order to reduce the interaction forces between the sextupole coils and the solenoid coils. For 28 GHz operation, the magnet assembly can produce peak mirror fields on axis of 3.6 T at injection, 2.2 T at extraction, and a radial sextupole field of 2.0 T at plasma chamber wall. Some excellent results of ion beam intensity have been produced and SECRAL has been put into operation to provide highly charged ion beams for HIRFL since May 2007. Secondly, a super-ferric dipole prototype of FAIR Super-FRS is being built by FCG (FAIR China Group) in cooperation with GSI. Its superconducting coils and cryostat is made and tested in the Institute of Plasma Physics (IPP, Hefei), and it more 50 tons laminated yoke was made in IMP. This super-ferric dipole static magnetic field was measured in IMP, it reach to the design requirement, ramping field and other tests will be done in the future. Thirdly, a 3 T superconducting homogenous magnetic field solenoid with a 70 mm warm bore has been developed to calibrate Hall sensor, some testing results is reported. And a penning trap system called LPT (Lanzhou Penning Trap) is now being developed for precise mass measurements.

重离子辐照甜高粱新品种选育及其诱变机理研究

利用重离子辐照技术对甜高粱种子进行不同剂量的诱变处理，并分析辐照后代的农艺性状、生理生化特性及基因组DNA的多态性差异，旨在选育出含糖量高、生物量高及抗逆性强的新品种，为发展生物质燃料乙醇产业提供优质的原料，并阐明重离子对甜高粱的诱变机理。主要结果如下： 1.甜高粱在田间的存活曲线表现为“类马鞍型”，随着辐照剂量的增加，其存活率先降后升再下降。 2.筛选出株高、单秆重、糖锤度、早熟型、茎粗等突变类型的材料，尤其是80Gy辐照剂量下从BJ0602中得到的早熟突变材料KFJT-1，生育期缩短了20天左右。 3.和未辐照株KFJT-CK相比，辐照突变株KFJT-1的萌芽指标表现为极显著差异（p＜0.01），其发芽势、发芽指数、活力指数和子叶长度、胚根鲜重及子叶鲜重分别下降了24％、12.69％、0.8108％和15.32％、76.27％、27.08％。 4. 利用RAPD技术对不同剂量的辐照处理检测出的多态性差异表明，不同剂量的碳离子束辐照后，不同辐照剂量对应的5种处理材料的DNA突变率分别0％、11.4％、12.2％、18.7％和17.7％。 重离子辐照可引起甜高粱各个方向的突变，有些突变材料生物量和含糖量均高，而有些突变材料表现出生长点消失、叶片扭曲、黄化等表型性状

碳离子束联合p53腺病毒重组体转染对肿瘤细胞生物学效应研究

肿瘤是严重威胁人类生命健康的常见病、多发病，不仅病因复杂、发生发展异常迅速，而且到目前为止，发病机理不完全清楚，尚无适应范围广和有特异疗效的治疗方法。因此，肿瘤治疗方法的探索依然是医学、生物学及其相关学科研究的热点。肿瘤的重离子治疗和基因治疗是近年来发展起来的新的肿瘤治疗方法。但它们同样或多或少存在一些不足。在肿瘤治疗方法的探索中，将两种或两种以上理化特性或生物学作用原理不尽相同的现有治疗方法有机结合，充分利用各自优势，取长补短，使治疗效果叠加，对肿瘤发挥协同或相加抑制作用。本研究将重离子辐射与p53腺病毒重组体(AdCMV-p53)转染有机结合，探讨了重离子辐射联合p53基因转导对肿瘤细胞的生物学作用及其可能机理。在低剂量γ辐射联合AdCMV-p53/GFP转染HT-29和PC-3细胞研究基础上，我们用不同剂量的AdCMV-p53/GFP转染经0.5 Gy、1.0 Gy、2.0 Gy 12C6+束/γ射线预辐射处理的人非小细胞肺癌(H1299细胞系，nullp53)，人肝癌细胞(HepG2细胞系，wtp53)和人宫颈癌细胞(Hela细胞系，wtp53，wtp53低水平表达)。用流式细胞分析法检测肿瘤细胞绿色荧光蛋白(GFP)、p53蛋白表达水平和细胞周期。DAPI染色后用荧光显微镜检测细胞凋亡。用RT-PCR检测外源性p53转录。用Western Blot检测外源性p53、MDM2和p21蛋白表达。用克隆形成法测定肿瘤细胞存活。通过与γ辐射联合腺病毒重组体转染组比较，观察了12C6+ 辐射联合腺病毒重组体转染对肿瘤细胞外源性p53蛋白表达、细胞周期阻滞、细胞凋亡和细胞增殖的影响。结果显示，12C6+ 辐射对AdCMV-GFP转染H1299、HepG2和Hela细胞的诱导作用明显强于γ辐射(p<0.05)。与γ辐射诱导AdCMV-GFP转染组相比，0.5 Gy 12C6+束辐射联合20 MOI AdCMV-p53转染组H1299细胞GFP阳性率增加约50% (其GFP阳性率提高到约90%)。0.5 Gy、1.0 Gy 12C6+辐射联合40 MOI AdCMV-p53转染组HepG2细胞GFP阳性率增加约44%(其阳性率分别达56.6%和76.4%)。0.5 Gy、1.0 Gy 12C6+ 束辐射联合40 MOI AdCMV-p53转染组Hela细胞GFP阳性率分别增加37.8%和50%(其阳性率分别达43.4%和59.8%)。12C6+ 辐射对AdCMV-p53转染H1299、HepG2和Hela细胞外源性p53蛋白表达的增强作用明显强于γ辐射(p<0.05)。12C6+ 辐射联合AdCMV-p53转染组各种细胞p53阳性率明显高于其它处理组同种细胞p53阳性率(p<0.05)。转染后第5天，γ辐射联合AdCMV-p53转染组3种细胞p53阳性率均降至对照水平。转染后第13天，12C6+ 辐射联合AdCMV-p53转染组3种细胞p53阳性率仍高达6－44%。12C6+ 辐射联合AdCMV-p53转染H1299细胞G0/G1、G2/M期细胞所占比例明显高于其它处理组G0/G1、G2/M期细胞所占比例(p<0.05)。与γ辐射联合AdCMV-p53转染组相比，12C6+ 辐射联合AdCMV-p53转染组G0/G1期细胞增加6－36%，G2/M期细胞增加了13－86%。12C6+ 辐射联合AdCMV-p53转染HepG2细胞G0/G1期细胞所占比例明显高于其它处理组G0/G1期细胞所占比例(p<0.05)；转染后第5天，1.0、2.0 Gy 12C6+ 辐射联合AdCMV-p53转染组G2/M期细胞所占比例明显高于γ辐射联合AdCMV-p53转染组G2/M期细胞所占比例(p<0.05)。各12C6+束辐射联合AdCMV-p53转染Hela细胞G0/G1和G2/M期细胞所占比例均明显高于单纯12C6+ 辐射组和γ射线辐射联合AdCMV-p53转染组G0/G1和G2/M期细胞所占比例(p<0.05)。各12C6+ 辐射联合AdCMV-p53转染H1299、HepG2和Hela细胞凋亡率明显高于等剂量12C6+ 单纯辐射和等剂量γ辐射联合AdCMV-p53转染组细胞凋亡率(p<0.05)。与等剂量单纯12C6+辐射和等剂量γ辐射联合AdCMV-p53转染组相比，12C6+ 辐射联合AdCMV-p53转染H1299细胞凋亡率分别增加8.0－66.0%和9.3－63.5%；12C6+束辐射联合AdCMV-p53转染HepG2细胞凋亡率分别增加0.8－32.7%和4.5－27.1%； 12C6+束辐射联合AdCMV-p53转染Hela细胞凋亡率分别增加4.8－30.7%和3.1－22.7%。低剂量12C6+ 辐射联合AdCMV-p53转染细胞存活率明显低于其它处理组同种细胞存活率(p<0.05)。结果提示，低剂量碳离子辐射对腺病毒重组体转染肿瘤细胞和靶细胞内外源p53蛋白表达的促进作用明显强于低剂量γ辐射。碳离子辐射联合AdCMV-p53转染通过促进外源性p53转导、靶细胞外源性p53蛋白表达、细胞周期阻滞和细胞凋亡等增强对肿瘤细胞的抑制。碳离子辐射联合AdCMV-p53转染对肿瘤细胞生物学作用与肿瘤细胞内在p53基因状态有关。总之，我们的研究表明，低剂量碳离子辐射联合AdCMV-p53转染，可通过促进腺病毒重组体对肿瘤细胞的转染、增强靶细胞外源性p53蛋白稳定表达及其由此而诱发的细胞周期阻滞与细胞凋亡等有效抑制肿瘤细胞。在临床上，碳离子辐射联合AdCMV-p53转染有望在提高肿瘤治疗效果的基础上，进一步降低碳离子辐射与AdCMV-p53转染的各自临床用量，减少碳离子辐射的毒副作用，降低AdCMV-p53转染的潜在生物危险性

深层治癌重离子束的配送

在辐射治疗应用方面，相比传统体外辐射疗法，高能量的重离子束流有着巨大的优势。近年来，世界上多数重离子治疗中心都对重离子的辐射特性已经进行了深入研究，从2006年起中国科学院近代物理所也开始了重离子辐射治疗肿瘤的临床实验。目前绝大多数重离子治癌中心都采用了包括一对独立的二极铁的束流配送系统，将从加速器引出的笔形束流在肿瘤的各层等深横截面上进行均匀照射。本文重点阐述了HIRFL-CSR重离子治癌装置中的束流配送系统的工作原理和分系统结构，包括深层治癌重离子束运线，终端扫描系统和根据治疗计划生成的扫描路径软件系统。第一部分简单介绍了世界上各大重离子医疗辐射工程，总结了医疗重离子加速器的设计经验，尤其对日本的HIMAC和德国GSI重离子治癌装置进行了详细介绍，同时对新型重离子治癌装置的特点和重离子治癌装置的发展方向进行了介绍。侧重分析研究了束流引出系统、控制系统和扫描系统的工作原理和相关在线设备，详细比较了两种扫描方式的优缺点。第二部分重点介绍了HIRFL-CSR加速器及其重离子辐射应用工程。CSR是中国第一台重离子冷却存储环，其主加速器CSRm是在兰州重离子治癌装置的核心，负责提供对应不同穿透深度不同能量的慢引出束流。兰州近代物理所的治癌临床实验分为三个阶段，其中第一阶段利用HIRFL辐照终端引出的重离子束流对浅层肿瘤进行适形照射。第二阶段利用CSRm引出的重离子束流开展对深层肿瘤的辐照实验，包括动物实验和临床实验。第三阶段在技术成熟后将小型医用重离子加速器向社会推广。第三部分中总结回顾了深层治癌重离子束运线的设计原理和和束运线的磁聚焦结构。对扫描系统（栅扫描和点扫描）进行了计算机模拟和束斑尺寸的控制方式进行了讨论。在重离子深层治癌进行第一次动物实验时，利用位于终端的分条电离室测试了治癌重离子束流的基本参量，得到了引出束流在垂直和水平方向以及束流微结构的品质信息，并用梯度法测量了束流的发射度。这些工作对于模拟不同引出束流情况对应的不同扫描方式时束流照射均匀度很有帮助，也给制定肿瘤的治疗计划提供了一些参考。最后论文还简单介绍了束流的共振引出系统，侧重说明引出束流的特性，提及重离子垂直治疗终端桶型旋转机架的设计

12C6+离子束辐射对大鼠骨的影响

放射性骨损伤是一种严重的放射病，通常由放射治疗引起。在进行重离子治癌研究的同时，我们应该考虑放射性骨损伤的预防。本文通过细胞和动物两方面的研究实验，初步评估了12C6+离子束对大鼠骨的影响。在细胞学方面，我们首次使用体外原代培养的方法，成功地培养了大鼠成骨细胞并进行了12C6+离子束照射实验。结果表明：1，细胞在2Gy以上剂量照射后，增殖受到了明显抑制，细胞存活率随剂量加大而下降；2，照射细胞在形态上发生了明显的变化，例如，细胞大小不一，透明度增大，丝状突起减少，核仁增多等，这些变化在不同剂量点表现有所不同；3，照射使以碱性磷酸酶活性为代表的细胞功能受到了不同程度的影响。与此同时，我们对这些现象和结果进行了比较深入的分析和讨论。另外，我们对细胞体外原代培养的方法进行了一些经验总结和讨论。在动物实验方面，我们用12C6+离子束分别对大鼠进行了全身照射和股骨部局部照射，以生物化学，物理学，力学的方法研究了照射大鼠在骨代谢，骨密度，骨生物力学等方面受到的影响并分析了各种结果出现的原因。实验结果表明：除血清碱性磷酸酶活性在照射剂量下无显著变化之外，受照大鼠的骨质合成能力，骨密度，股骨的最大承载力和最大应力都出现了与剂量负相关的变化。在局部照射中，2Gy以下的剂量对大鼠股骨各检测指标没有显著性影响

重离子束介导植物转基因研究及其辐射育种的生物学效应

遗传转化是基因工程的一个重要研究方向，而利用重离子束介导转基因技术是近年来新兴的一门技术，这种技术的原理是利用离子束对植物细胞的蚀刻作用，造成受体细胞表面的损伤和穿孔，从而引起细胞膜透性和跨膜电场的改变，将外源基因引入植物细胞。特别是近年来植物总D NA转化技术得到了发展，借助离子束介导转移活性裸露D NA大分子已成为当前引人注目的一个研究方向。本论文将利用这一基因转导的新技术，探索基因高转化效率和稳定表达的转基因方法。而且，本论文还结合辐射育种研究了植物种子受辐照后的相关生物学效应。材料与方法： 本论文采用兰州重离子研究装置(HIRFL)加速的碳离子辐照植物种子，种子经辐照后，以常规手段进行基因转导。另一部分被照种子则萌发后，统计其发芽率，发芽势，微核，并进一步测定其多项酶学指标，分析它们与剂量之间的关系。结果：·低剂量辐照不能抑制种子的发芽率，反而有促进种子萌发的作用·低剂量辐照也能激活细胞的防御系统，部分抗氧化酶活性与LET有相关性。·作为主要抗氧化物质的SOD（超氧化物歧化酶）、CAT（过氧化氢酶）对剂量的反应不灵 敏，低剂量作用时不能发挥作用。这种情况卞可能主要由GsH佩Px（谷肤甘肤过氧化物酶）和NOS（一氧化氮合酶）发挥清除自由基的作用一·低剂量辐照可以促进种子萌发，高剂量则抑制种子的发芽。碳离子和电子辐照都能激活细胞的防系统。在幼苗期，抗氧化酶的分布不尽相同：SOD9超氧化物歧化酶（和GSH-PX（谷胱甘肽过氧化物酶）的活性是根茎部高于叶片部，而CAT（过氧化氢酶）的活性是叶片部更高。