高精度材料二次电子产额测试装置的设计与研究
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摘要
粒子加速器中,带电粒子与真空室内壁碰撞产生的二次电子是影响束流品质的重要原因之一,特别在正电子和质子加速器中,真空室内壁在粒子轰击下产生大量二次电子,这些二次电子聚集形成电子云,对束流的稳定性、能量、发射度、寿命等均造成不利影响。因此,研究加速器真空室常用金属材料的二次电子发射(SEE)特性很有必要。本文设计了一台高精度材料二次电子产额(SEY)测量装置,采用能量范围为50~5000e V的低能电子枪,可用于测量材料的二次电子产额。通过测试,获得了不锈钢和无氧铜的SEE特性曲线,不锈钢与无氧铜的最大二次电子产额分别为2.5和1.82,与国际上采用相同测试方法的测试结果基本一致。
In particle accelerators, the secondary electrons resulting from interaction between particles and vacuum chamber have a great impact on the beam quality. Especially for positron and proton accelerators, massive electrons will lead to the electron cloud, which adversely affect the stability, energy, emittance and beam life. We studied the secondary electron emission(SEE) of metal used for accelerators. A SEE measurement system with 50 ~5000e V low energy electron gun was designed. Using the secondary electron emission yield(SEY) test setup, we obtained the SEY of stainless steel and oxygen free copper. The maximum SEY of stainless steel and oxygen free copper are 2.5 and 1.82, respectively. Compared with the results reported by other research institutions, it's indicated that our SEY test setup is reliable.
In particle accelerators, the secondary electrons resulting from interaction between particles and vacuum chamber have a great impact on the beam quality. Especially for positron and proton accelerators, massive electrons will lead to the electron cloud, which adversely affect the stability, energy, emittance and beam life. We studied the secondary electron emission(SEE) of metal used for accelerators. A SEE measurement system with 50 ~5000e V low energy electron gun was designed. Using the secondary electron emission yield(SEY) test setup, we obtained the SEY of stainless steel and oxygen free copper. The maximum SEY of stainless steel and oxygen free copper are 2.5 and 1.82, respectively. Compared with the results reported by other research institutions, it's indicated that our SEY test setup is reliable.
引文
[1]Hartung W,Conway J,Dennett C et al.Measurements of Secondary Electron Yield of Metal Surfaces and Films with Exposure to a Realistic Accelerator Environment[C].Proceedings of IPAC2013,Shanghai,China,THPFI087:3493-3495.
[2]Kirby R E,King F K,Secondary electron emission yields from PEP-II accelerator materials[J].Nuclear Instruments and Methods in Physics Research A 469(2001)1-12.
[3]Scott D J,Capista D,Duel K L et al.Secondary Electron Yield Measurements of Fermilab’s Main Injector Vacuum Vessel[C].Proceedings of IPAC2012,New Orleans,Louisiana,USA,MOPPC019:166-168.
[4]Yichen Ji,Linda Spentzouris,Robert Zwaska.Secondary Electron Yield Measurement and Electron Cloud Simulation at Fermilab[C].Proceedings of IPAC2015,Richmond,VA,USA,MOPMA039:629-632.
[5]张耀锋,王勇,尉伟等.真空室材料二次电子产额特性研究[J].中国物理C,2008,32(1):68-70.
[6]谢爱根,裴元吉,王荣等.金属的有效真二次电子发射系数与高能原电子入射角的关系[J].高能物理与核物理,Vol.29,No.5:530-532.
[7]Kim J,Asner D,Conway J,et al.In Situ Secondary Electron Yield Measurement System at Cesr TA[C].Proceedings of 2011 Particle Accelerator Conference,New York,NY,USA,TUP230:1253-1255.
[8]Sihui Wang,Oleg B.Malyshev,Reza Valizadeh et al.The secondary electron yield from transition metals[C].Proceedings of IPAC2014,Dresden,Germany,WEPME057:2403-2405.
[9]Balcon N,Payan D,Belhaj M et al.Secondary Electron Emission on Space Materials:Evaluation of the Total Secondary Electron Yield from Surface Potential Measurements[C].IEEE transactions on plasma science,2012,40(2):282-290.
[10]Jacques Cazaux.Secondary electron emission and charging mechanisms in Auger Electron Spectroscopy and related e-beam techniques[J].Journal of Electron Spectroscopy and Related Phenomena,2010,176(1-3):58-79.
[11]Reza Valizadeh,Oleg B.Malyshev,Sihui Wang,et al.Low secondary electron yield engineered surface for electron cloud mitigation[J].Applied Physics Letters2014,105,231605.
[2]Kirby R E,King F K,Secondary electron emission yields from PEP-II accelerator materials[J].Nuclear Instruments and Methods in Physics Research A 469(2001)1-12.
[3]Scott D J,Capista D,Duel K L et al.Secondary Electron Yield Measurements of Fermilab’s Main Injector Vacuum Vessel[C].Proceedings of IPAC2012,New Orleans,Louisiana,USA,MOPPC019:166-168.
[4]Yichen Ji,Linda Spentzouris,Robert Zwaska.Secondary Electron Yield Measurement and Electron Cloud Simulation at Fermilab[C].Proceedings of IPAC2015,Richmond,VA,USA,MOPMA039:629-632.
[5]张耀锋,王勇,尉伟等.真空室材料二次电子产额特性研究[J].中国物理C,2008,32(1):68-70.
[6]谢爱根,裴元吉,王荣等.金属的有效真二次电子发射系数与高能原电子入射角的关系[J].高能物理与核物理,Vol.29,No.5:530-532.
[7]Kim J,Asner D,Conway J,et al.In Situ Secondary Electron Yield Measurement System at Cesr TA[C].Proceedings of 2011 Particle Accelerator Conference,New York,NY,USA,TUP230:1253-1255.
[8]Sihui Wang,Oleg B.Malyshev,Reza Valizadeh et al.The secondary electron yield from transition metals[C].Proceedings of IPAC2014,Dresden,Germany,WEPME057:2403-2405.
[9]Balcon N,Payan D,Belhaj M et al.Secondary Electron Emission on Space Materials:Evaluation of the Total Secondary Electron Yield from Surface Potential Measurements[C].IEEE transactions on plasma science,2012,40(2):282-290.
[10]Jacques Cazaux.Secondary electron emission and charging mechanisms in Auger Electron Spectroscopy and related e-beam techniques[J].Journal of Electron Spectroscopy and Related Phenomena,2010,176(1-3):58-79.
[11]Reza Valizadeh,Oleg B.Malyshev,Sihui Wang,et al.Low secondary electron yield engineered surface for electron cloud mitigation[J].Applied Physics Letters2014,105,231605.