共查询到20条相似文献,搜索用时 0 毫秒
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Roger HUTTON 《核技术(英文版)》2003,14(4)
A brief introduction to the historical background and current status of electron beam ion traps (EBITs) is presented. The structure and principles of an EBIT for producing highly charged ions are described. Finally, EBITs as a potential tool in hot-plasma diagnostics and in studying frontier problems of highly charged ion physics are discussed. 相似文献
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《等离子体科学和技术》2020,22(8):85001
Based on the beam–plasma system model established in this paper, the trajectory of the electron beam in the ion channel is studied quantitatively through the envelope equation. Under different initial system parameters, the focusing transmission conditions of the beam in the ion channel are discussed. Then, a series of particle-in-cell simulations are performed, which generally versifies the theoretical results and shows some further details of the focusing behavior of the beam. It is found that the deceleration of some electrons around the focusing point or the beam–plasma interaction at the ion channel boundary will result in the generation of the residual electrons,which forms the electron return current that leads to the new instabilities influencing the focusing characteristics of the beam. 相似文献
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A. A. Bettiol I. Rajta E. J. Teo J. A. van Kan F. Watt 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2002,190(1-4):154-159
Proton beam micromachining (PBM) is a direct write lithographic technique that uses a focused beam of MeV protons to pattern a resist material. The most common resist material used in the PBM process is SU-8 which is usually spin coated onto various substrates. The method used to ensure that the correct dose is delivered to the sample during irradiation is Rutherford backscattering spectrometry (RBS). There are however limitations to using the RBS signal for normalizing the dose in highly sensitive resist materials such as SU-8. The limited number of backscatter events means that normalizing the dose for every pixel is not possible. The secondary electron yield for SU-8 is at least an order of magnitude higher than that for backscattered ions. With an appropriate detector these signals can be essentially used for ion detection and thus used to accurately monitor ion dose. In this paper we investigate the secondary electron yield from SU-8 polymer resist layers of varying thickness on silicon. It is shown that the signals produced during MeV ion irradiation can be directly related to the ion dose and used for dose normalization during PBM. 相似文献
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V. Toivanen O. Steczkiewicz O. Tarvainen T. Ropponen J. Ärje H. Koivisto 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2010,268(9):1508-1516
The results of a series of measurements studying the possibility to use neutral gas feeding into the beam line as a way to improve the quality of the heavy ion beams produced with an electron cyclotron resonance ion source (ECRIS) are presented. Significant reduction of the beam spot size and emittance can be achieved with this method. The observed effects are presumably due to increased space charge compensation degree of the ion beam in the beam line section between the ion source and the analyzing magnet. This is the region where the neutral gas was injected. It is shown that the effects are independent of the ion source tuning. Transmission measurements through the beam line and K-130 cyclotron have been carried out to study the effects of improved ion beam quality to the transmission efficiency. 相似文献
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上海电子束离子阱低温超导磁体系统的研制 总被引:1,自引:0,他引:1
介绍了上海电子束离子阱(Electron beam ion trap,EBIT)装置低温超导磁体系统的研制过程和测试结果.超导磁体由一对上下布置的Helmholtz线圈组成,中心最大磁场强度可达5.3 T,两线圈的峰值磁场偏差小于3×10-4 T,在中心轴线上±10mm内磁场均匀度好于2×10-4,磁场衰减率在8 h内小于1×10-4.低温系统采用双冷屏结构,通过二级G-M制冷机冷却冷屏来降低液氦的蒸发量.系统液氦灌注达到平衡后,液氦的平均蒸发量为1.1 L/h,基本满足了用户的要求. 相似文献
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电子束辐照降解二氯苯废水的研究 总被引:3,自引:0,他引:3
二氯苯是重要的有机污染物,采用常规处理方法难以降解.利用束流为1 mA、电子束能量为1.5 MeV的高能电子束辐照处理邻,间,对-二氯苯的模拟废水.辐照剂量分别为35 kGy、70 kGy、105 kGy、140 kGy、210 kGy.实验表明电子束能够降解氯苯类废水且效果很好,邻二氯苯、间二氯苯、对二氯苯的降解率为50%时所需剂量分别为:38 kGy、35 kGy、46 kGy.辐照降解过程中氯离子的质量浓度增加,辐照后溶液呈强酸性,pH在2-3.根据实验结果,本文给出了二氯苯的辐照降解机理并初步探讨了辐解中间产物的类型. 相似文献
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In a 2.45 GHz electron cyclotron resonance(ECR) ion thruster powered with rod antenna under a cross magnetic field, abnormal behaviours such as sudden drop of ion beam current(Ib) and larger increasing-rate of Ibin the high microwave power(Pw) discharges at high gas flow rates were observed. A differential method was proposed to reveal the changes in the radial profiles of gray values extracted from the end-view discharge images. The increasing-rate of Ibwith respect to Pwwas used to evaluate efficiencies of ion production and transport. Analyses indicate that discharges are dominantly sustained by ordinary wave via electron heating in the electron plasma resonance layer that can shift along the rod-antenna, and extraordinary wave can only ignite a discharge in the ECR layer in the low gas flow rate regime. In terms of the confinement region defined by the magnetic field lines intercepting with the screen grid, the confinement region of the optimized 2.45 GHz cross magnetic field takes the shape of hourglass, enabling the high increasing-rate of I_b with respect to P_w in high power discharges at high gas flow rates.Correlated with the accompanied bright boundary layer appearing in the differentiated image, the sudden drop of I_b in the low gas flow rate regime is attributed to the discharge ignited by the enhanced extraordinary wave in the ECR layer neighbouring the narrowest confinement region,where the produced ions can promptly enter the loss region. 相似文献
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根据射程法原理,在上海二级标准剂量学实验室对辐射加工用加速器电子束能量的测量方法进行了实验研究,并在3个辐射工厂对3台3MeV、20mA高频高压型加速器的电子束进行了能量测定.结果表明,在1-3MeV能量范围内,能量测定准确度优于±10%. 相似文献
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利用电子束辐射降解水中的2-氯苯酚(2-CP),4-氯苯酚(4-CP)和2,4-2氯苯酚(2,4-DCP),研究了辐照剂量对初始浓度各为200mg/L的三种氯代苯酚以及浓度各为50mg/L的三种混合物辐射降解、去除有机氯及溶液pH值的影响。用HPLC测定了辐照溶液中2-CP、4-CP和2,4-DCP的含量,测试结果表明,随着辐照剂量的增加氯代苯酚的降解增加,溶液中的氯离子增加,pH值减小。浓度为200mg/L的三种溶液,在同样的辐射剂量率下,其辐射降解速度和氯离子产率的顺序为2,4-DCP>4-CP>2-CP;对浓度各为50mg/L氯代苯酚的混合物溶液,2,4-DCP的辐射降解速度最大,4-CP和2-CP的降解速度几乎相同。在辐照剂量为21kGy时,对浓度为200mg/L的三种溶液,其辐射降解率分别为93.0%(2-CP)、98.5%(4-CP)和99.4%(2,4-DCP),氯离子产率为55.4%、71.3%和69.0%,降解率为90%所需剂量(D90)分别为18.0kGy(2-CP)、11.4kGy(4-CP)和6.1kGy(2,4-DCP)。浓度各为50mg/L混合体系中的D90值分别为16.1kGy(2-CP)、15.6kGy(4-CP)和12.8kGy(2,4-DCP)。 相似文献
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and laser mattering particle size distribution analysis. Average size of the nanoparticles was about 32 nm with a narrow size distribution. Melting point of the nanoparticles was about 451.3 ℃. 相似文献
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JIAOZheng WANGDeqing LIZhen LUSenlin WUMinghong 《辐射研究与辐射工艺学报》2005,23(2):107-107
There are many traditional ways to improve sensitivity and selectivity of semiconductor gas sensors, such as metal ions adulteration and surface modification. In this paper 1.75 MeV electron beam was used to modify surface structure of tin dioxide gas sensors, and the gas sensing characteristics were studied. Results showed that the sensitivity and selectivity of SnO2 sensors were improved after the electron beam irradiation. 相似文献
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