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我们通过实验测量1.5 keV电子穿越玻璃直管/锥管的二维角分布的时间演化,研究了低能电子与绝缘玻璃管相互作用的动力学过程.观察到了低能电子穿越玻璃直管和锥管后其强度随时间呈现振荡.穿透的强度出现振荡峰结构,在出现峰的地方,透射的电子最开始出现微弱的圆点,随后微弱的圆点变为较明显的亮点,此后亮点逐渐变大变亮,接着变暗,最后亮斑迅速消失,同时透射电子的角分布中心伴随移动.这种行为显示了低能电子在玻璃管内的充放电呈现振荡行为,当入射电荷累积足够大时,存在一个快速放电的通道,后迅速充电产生阻止电子穿越的电场.对比锥管后的角分布和直管的角分布,我们发现锥管的穿透电子束流密度比直管的大40%.锥管的充放电的时间比直管快,这显示了锥管更容易快速放电,其由于充电建立的电场也更容易影响传输的电子.电子在玻璃直管和锥管的快速充放电的动力学过程显示出电子的传输机制与高电荷态离子有很大不同,其快速充放电过程显示了带负电的电子与绝缘体材料相互作用中的充放电过程与带正电离子的不同.It has been found that the transmission rate of the electrons through insulating capillaries as a function of time/incident charge is not the same as that of the ions. The question arises that by using the electrons, if the negative charge patches can be formed to facilitate the transmission of the following electrons, thereby substantiating that the so-called guiding effect works also for electrons. This study aims to observe the time evolutions of the transmission of electrons through a straight glass tube and a tapered glass capillary. This will reveal the details of how and (or) if the negative charge patches can be formed when the electrons transport through them. In this work, a set of MCP/phosphor two-dimensional detection system based on Labview platform is developed to obtain the time evolution of the angular distribution of the transmitted electrons. The pulsed electron beams are obtained to test our detection system. The time evolution of the angular profile of 1.5 keV electrons transmitting through the glass tube/capillary is observed. The transmitted electrons are observed on the detector for a very short time and disappear for a time and then appear again for both the glass tube and tapered glass capillary, leading to an oscillation. The positive charge patches are formed in the insulating glass tube and tapered glass capillary since the secondary electron emission coefficient for the incident energy is larger than 1. It is due to the fact that fast discharge of the deposited charge leads to the increase of the transmission rate, while the fast blocking of the incident electrons due to the deposited positive charge leads to the decrease of the transmission rate. The geometrical configuration of the taper glass capillary tends to make the secondary electrons deposited at the exit part to form the negative patches that facilitate the transmission of electrons. This suggests that if the stable transmission needs to be reached for producing the electron micro-beam by using tapered glass capillaries, the steps must be taken to have the proper grounding and shielding of the glass capillaries and tubes. Our results show a difference in transmission through the insulating capillary between electrons and highly charged ions.
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Keywords:
- low energy electron /
- the full angular distribution of the transmitted electrons /
- glass capillaries /
- highly charged ions
[1] Stolterfoht N, Bremer J H, Hoffmann V, Hellhammer R, Fink D, Petrov A, Sulik B 2002 Phys. Rev. Lett. 88 133201
[2] Stolterfoht N, Hellhammer R, Bundesmann J, Fink D, Kanai Y, Hoshino M, Kambara T, Ikeda T, Yamazaki Y P 2007 Phys. Rev. A 76 022712
[3] Schiessl K, Palfinger W, Tókési K, Nowotny H, Lemell C, Burgdórfer J 2005 Phys. Rev. A 72 062902
[4] Skog P, Zhang H Q, Schuch R 2008 Phys. Rev. Lett. 101 223202
[5] Das S, Dassanayake B S, Winkworth M, Baran J L, Stolterfoht N, Tanis J A 2007 Phys. Rev. A 76 042716
[6] Wickramarachchi S J, Dassanayake B S, Keerthisinghe D, Ikeda T, Tanis J A 2013 Phys. Scr. T156 014057
[7] Schiessl K, Tókési K, Solleder B, Lemell C, Burgdórfer J 2009 Phys. Rev. Lett. 102 163201
[8] Zhang H Q, Akram N, Skog P, Soroka I L, Trautmann C, Schuch R 2012 Phys. Rev. Lett. 108 193202
[9] Christoph L, Joachim B, Friedrich A 2013 Prog. Surf. Sci. 88 237
[10] Wang W, Chen J, Yu D Y, Wu Y H, Zhang M W, Cai X H 2011 High Power Laser and Particle Beams 23 1065 (in Chinese)[王伟, 陈婧, 于得洋, 武晔虹, 张明武, 蔡晓红2011强激光与粒子束23 1065]
[11] Chen Y F, Chen X M, Lou F J, Xu J Z, Shao J X, Sun G Z, Wang J, Xi F Y, Yin Y Z, Wang X A, Xu J K, Cui Y, Ding B W 2010 Acta Phys. Sin. 59 222 (in Chinese)[陈益峰, 陈熙萌, 娄凤君, 徐进章, 邵剑雄, 孙光智, 王俊, 席发元, 尹永智, 王兴安, 徐俊奎, 崔莹, 丁宝卫2010物理学报59 222]
[12] ALPHA Collaboration, Andresen G B, et al. 2009 Rev. Sci. Instrum. 80 123701
[13] Variale V 2015 Physics Procedia 66 242
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[1] Stolterfoht N, Bremer J H, Hoffmann V, Hellhammer R, Fink D, Petrov A, Sulik B 2002 Phys. Rev. Lett. 88 133201
[2] Stolterfoht N, Hellhammer R, Bundesmann J, Fink D, Kanai Y, Hoshino M, Kambara T, Ikeda T, Yamazaki Y P 2007 Phys. Rev. A 76 022712
[3] Schiessl K, Palfinger W, Tókési K, Nowotny H, Lemell C, Burgdórfer J 2005 Phys. Rev. A 72 062902
[4] Skog P, Zhang H Q, Schuch R 2008 Phys. Rev. Lett. 101 223202
[5] Das S, Dassanayake B S, Winkworth M, Baran J L, Stolterfoht N, Tanis J A 2007 Phys. Rev. A 76 042716
[6] Wickramarachchi S J, Dassanayake B S, Keerthisinghe D, Ikeda T, Tanis J A 2013 Phys. Scr. T156 014057
[7] Schiessl K, Tókési K, Solleder B, Lemell C, Burgdórfer J 2009 Phys. Rev. Lett. 102 163201
[8] Zhang H Q, Akram N, Skog P, Soroka I L, Trautmann C, Schuch R 2012 Phys. Rev. Lett. 108 193202
[9] Christoph L, Joachim B, Friedrich A 2013 Prog. Surf. Sci. 88 237
[10] Wang W, Chen J, Yu D Y, Wu Y H, Zhang M W, Cai X H 2011 High Power Laser and Particle Beams 23 1065 (in Chinese)[王伟, 陈婧, 于得洋, 武晔虹, 张明武, 蔡晓红2011强激光与粒子束23 1065]
[11] Chen Y F, Chen X M, Lou F J, Xu J Z, Shao J X, Sun G Z, Wang J, Xi F Y, Yin Y Z, Wang X A, Xu J K, Cui Y, Ding B W 2010 Acta Phys. Sin. 59 222 (in Chinese)[陈益峰, 陈熙萌, 娄凤君, 徐进章, 邵剑雄, 孙光智, 王俊, 席发元, 尹永智, 王兴安, 徐俊奎, 崔莹, 丁宝卫2010物理学报59 222]
[12] ALPHA Collaboration, Andresen G B, et al. 2009 Rev. Sci. Instrum. 80 123701
[13] Variale V 2015 Physics Procedia 66 242
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