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低能正电子碰撞原子内壳层电离截面的实验数据目前还很缺乏,从而影响了对近年来发展的各相关理论模型的检验,限制了慢正电子束流技术在诸多领域中的应用.本文采用慢正电子束流装置产生的8–9.5 keV正电子束碰撞纯厚Ti靶,利用硅漂移探测器(SDD)收集正电子碰撞Ti靶产生的X射线,同时采用高纯锗探测器在线获得与靶碰撞的入射正电子数,从而得到Ti的K壳层实验产额,并基于蒙特卡罗模拟程序PENELOPE获得模拟产额.将实验产额分别与内壳层电离截面数据库采用经典光学数据模型(ODM)和扭曲波玻恩近似理论模型(DWBA)的蒙特卡罗模拟产额进行对比,发现基于ODM理论模型的模拟产额与实验值有较大的偏差,基于DWBA理论模型的模拟产额与实验结果符合较好.根据实验产额和基于DWBA理论模型的模拟产额的比较结果,对蒙特卡罗模拟程序使用的DWBA理论模型数据库进行修正后再进行模拟和比较,从而得到可靠的8–9.5 keV正电子致Ti原子K壳层电离截面数据.
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关键词:
- 正电子碰撞厚Ti靶 /
- K壳层电离 /
- 蒙特卡罗模拟 /
- 扭曲波玻恩近似理论模型
Due to lack of experimental data of the inner shell ionization cross sections induced by low-energy positron, advanced theoretical models developed in recent years cannot be correctly evaluated, and the application of slow positron beam technique is greatly limited. Here we present the method of obtaining reliable experiment data of atomic inner-shell ionization cross section by positron impact. In this work, the slow positron beam device is used to generate 8-9.5 keV positron beams impacting on a pure thick Ti target, and the silicon drift detector (SDD) is adopted to collect the X-ray spectra produced by positrons impacting on thick Ti target, and the incident positron numbers are obtained by applying an HPGe detector to on-line collect annihilation photons. Then the experimental characteristic X-ray yields of Ti K shell impacted by 8-9.5 keV positron could be acquired. Meantime, the simulated characteristic X-ray yields are acquired by the PENELOPE program simulating the experiments. In the comparison between the experimental yields and the simulated yields based on two sets of different inner shell ionization cross section database in the PENELOPE code, i.e. the optical data model (ODM) and the distorted-wave Born approximation model (DWBA), there is a large difference between the simulated data from the ODM theoretical model and the experimental values, while the simulated yields from the DWBA theoretical model are in good agreement with the experimental results. Accordingly, a correction factor is introduced to modify the DWBA theoretical model database which is used in the PENELOPE, and then the experimental process is re-simulated. When the simulated yields and the experimental yields are in the highest consistence, the reliable Ti K shell ionization cross sections impacted by 8-9.5 keV positron could be obtained. The biggest advantage of using this method to obtain atomic inner-shell ionization cross section impacted by positron is that the effects of the multiple scattering of incident positrons in the thick target, from the bremsstrahlung and annihilation photons, and other secondary particles on the experimental characteristic X-rays do not need calculating (the calculation method that has been developed previously cannot give the more correct result about the contribution of the multiple scattering of incident positrons, from the bremsstrahlung and annihilation photons, and other secondary particles to characteristic X-rays).-
Keywords:
- positron collisions purely thick Ti target /
- Ti K shell ionization /
- Monte Carlo simulation /
- distorted-wave Born approximation model
[1] An Z, Hou Q 2008 Phys. Rev. A 77 042702
[2] Wang J J, Gong J, Gong Z L, Yan X L, Wang B 2009 The second National Symposium on Nuclear Technology and Applied Research Mianyang, China, May 1, 2009 p331 (in Chinese) [王君君, 龚静, 宫振丽, 闫晓丽, 王波 2009 第二届全国核技术及应用研究学术研讨会 中国绵阳, 2009年5月1日, 第331页]
[3] Llovet X, Powell C J, Salvat F, Jablonski A 2014 J. Phys. Chem. Ref. Data 43 013102
[4] Sepúlveda A, Bertol A P, Vasconcellos M A Z, Trincavelli J, Hinrichs R, Castellano G 2014 J. Phys. B:At. Mol. Opt. Phys. 47 215006
[5] Zhao J L, An Z, Zhu J J, Tan W J, Liu M T 2017 Radiat. Phys. Chem. 134 71
[6] Qian Z C, Wu Y, Chang C H, Yuan Y, Mei C S, Zhu J J, Moharram K 2017 Europhys. Lett. 118 13001
[7] Zhao J L, Tian L X, Li X L, An Z, Zhu J J, Liu M T 2015 Radiat. Phys. Chem. 107 47
[8] Nagashima Y, Saito F, Itoh Y 2004 Phys. Rev. Lett. 92 223201
[9] Nagashima Y, Shigeta W, Hyodo T 2007 Radiat. Phys. Chem. 76 465
[10] Tian L X, Liu M T, Zhu J J, An Z, Wang B Y, Qin X B 2012 Plasma Sci. Technol. 14 434
[11] Hippler R 1990 Phys. Lett. A 144 81
[12] Luo S, Joy D C 1991 Microbeam Analysis (Vol. 1) (San Francisco:San Francisco Press) pp67-68
[13] Khare S P, Wadehra J M 1996 Can. J. Phys. 74 376
[14] Segui S, Dingfelder M, Salvat F 2003 Phys. Rev. A 67 062710
[15] Colgan J, Fontes C J, Zhang H L 2006 Phys. Rev. A 73 062711.
[16] Salvat F, Fernández-Vaea J M, Sempau J 2005 PENELOPE-2005, A Code System for Monte Carlo Simulation of Electron and Photon Transport (Vol. 1) (Issy-les-Moulineau:OECD/NEA Data) ppix-xii
[17] Zhu J J, An Z, Liu M T, Tian L X 2009 Phys. Rev. A 79 052710
[18] Cullen D E, Hubbell J H, Kissel L 1997 Report UCRL-0400 6 5
[19] Ribberfors R 1983 Phys. Rev. A 27 3061
[20] Tian L X, Zhu J J, Liu M T, An Z 2009 Nucl. Instr. Meth. Phys. Res. B 267 3495
[21] Bote D, Llovet X, Salvat F 2008 J. Phys. D:Appl. Phys. 41 105304
[22] Sempau J, Fernández-Vaea J M, Acosta E, Salvat F 2003 Nucl. Instr. Meth. Phys. Res. B 207 107
[23] Salvat F, Llovet X, Fernández-Vaea J M, Sempau J 2006 Microchim. Acta 155 67
[24] Mayol R, Salvat F 1990 Phys. B 23 2117
[25] He C Q, Wang J C, Zhu J, Wang S J 2013 Mater. Sci. Forum. 733 314
[26] Kuang P, Han X L, Cao X Z, Xia R, Zhang P, Wang B Y 2017 Chin. Phys. B 26 057802
[27] Kuang P 2017 Ph. D. Dissertation (Beijing:Institute of High Energy Physics, Chinese Academy of Sciences) (in Chinese) [况鹏 2017 博士学位论文(北京:中国科学院高能物理研究所)]
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[1] An Z, Hou Q 2008 Phys. Rev. A 77 042702
[2] Wang J J, Gong J, Gong Z L, Yan X L, Wang B 2009 The second National Symposium on Nuclear Technology and Applied Research Mianyang, China, May 1, 2009 p331 (in Chinese) [王君君, 龚静, 宫振丽, 闫晓丽, 王波 2009 第二届全国核技术及应用研究学术研讨会 中国绵阳, 2009年5月1日, 第331页]
[3] Llovet X, Powell C J, Salvat F, Jablonski A 2014 J. Phys. Chem. Ref. Data 43 013102
[4] Sepúlveda A, Bertol A P, Vasconcellos M A Z, Trincavelli J, Hinrichs R, Castellano G 2014 J. Phys. B:At. Mol. Opt. Phys. 47 215006
[5] Zhao J L, An Z, Zhu J J, Tan W J, Liu M T 2017 Radiat. Phys. Chem. 134 71
[6] Qian Z C, Wu Y, Chang C H, Yuan Y, Mei C S, Zhu J J, Moharram K 2017 Europhys. Lett. 118 13001
[7] Zhao J L, Tian L X, Li X L, An Z, Zhu J J, Liu M T 2015 Radiat. Phys. Chem. 107 47
[8] Nagashima Y, Saito F, Itoh Y 2004 Phys. Rev. Lett. 92 223201
[9] Nagashima Y, Shigeta W, Hyodo T 2007 Radiat. Phys. Chem. 76 465
[10] Tian L X, Liu M T, Zhu J J, An Z, Wang B Y, Qin X B 2012 Plasma Sci. Technol. 14 434
[11] Hippler R 1990 Phys. Lett. A 144 81
[12] Luo S, Joy D C 1991 Microbeam Analysis (Vol. 1) (San Francisco:San Francisco Press) pp67-68
[13] Khare S P, Wadehra J M 1996 Can. J. Phys. 74 376
[14] Segui S, Dingfelder M, Salvat F 2003 Phys. Rev. A 67 062710
[15] Colgan J, Fontes C J, Zhang H L 2006 Phys. Rev. A 73 062711.
[16] Salvat F, Fernández-Vaea J M, Sempau J 2005 PENELOPE-2005, A Code System for Monte Carlo Simulation of Electron and Photon Transport (Vol. 1) (Issy-les-Moulineau:OECD/NEA Data) ppix-xii
[17] Zhu J J, An Z, Liu M T, Tian L X 2009 Phys. Rev. A 79 052710
[18] Cullen D E, Hubbell J H, Kissel L 1997 Report UCRL-0400 6 5
[19] Ribberfors R 1983 Phys. Rev. A 27 3061
[20] Tian L X, Zhu J J, Liu M T, An Z 2009 Nucl. Instr. Meth. Phys. Res. B 267 3495
[21] Bote D, Llovet X, Salvat F 2008 J. Phys. D:Appl. Phys. 41 105304
[22] Sempau J, Fernández-Vaea J M, Acosta E, Salvat F 2003 Nucl. Instr. Meth. Phys. Res. B 207 107
[23] Salvat F, Llovet X, Fernández-Vaea J M, Sempau J 2006 Microchim. Acta 155 67
[24] Mayol R, Salvat F 1990 Phys. B 23 2117
[25] He C Q, Wang J C, Zhu J, Wang S J 2013 Mater. Sci. Forum. 733 314
[26] Kuang P, Han X L, Cao X Z, Xia R, Zhang P, Wang B Y 2017 Chin. Phys. B 26 057802
[27] Kuang P 2017 Ph. D. Dissertation (Beijing:Institute of High Energy Physics, Chinese Academy of Sciences) (in Chinese) [况鹏 2017 博士学位论文(北京:中国科学院高能物理研究所)]
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