摘要
为实时评估0~100km高度范围内的大气中子全球分布,对宇宙线在地磁场和大气中的传输过程进行了分析.利用蒙特卡罗方法工具包Geant 4,预先计算不同能量的粒子在大气层中产生的次级粒子能谱分布,形成大气次级粒子数据库,并与相关模型进行对比,验证了该数据库的有效性和可靠性.以实测或预报的空间环境参数作为输入,计算同步轨道银河宇宙线和太阳质子事件能谱以及100 km高度上的地磁垂直截止刚度,最终得到大气层顶上的粒子能谱.通过对大气次级粒子数据库的线性插值,实现1h分辨率的大气中子能谱和辐射剂量全球分布的实时计算.
In order to evaluate the global distribution of atmospheric neutron at 0~100 km altitude for real time, the propagation of cosmic rays in the geomagnetic field and the atmosphere is analyzed.By using the TSY05 and MAGNETOCOSMICS model, the real-time calculation of global geomagnetic cut-off rigidities with 1 h resolution is realized. The spherical shell geometry model is established at intervals of 1 km using NLRMSISE-00 model, and the spectrum distribution of secondary particles generated by different particles is calculated by the Monte Carlo simulation techniques, namely, the Geant 4 toolkit, then an atmospheric neutron database is created. Compared with EXPACS model,the validity and reliability of the database are verified. Based on the observed or predicted space environment parameters, the energy spectra of the cosmic ray and the solar proton event in the synchronous orbit are calculated, and the effective vertical cut-off rigidities in function of latitude and longitude at the altitude of 100 km. The atmospheric neutron and effective dose are calculated by using linear interpolation per hour.
引文
[1] TABER A, NORMAND E. Single event upset in avionics[J]. IEEE Trans. Nucl. Sci., 1993, 40(2):120-126
[2] XUE Haihong, WANG Qunyong, CHEN Dongmei, et al.Neutron single event effects testing and evaluation method for avionics[J]. J. Beijing Univ. Aeron. Astron., 2015,41(10):1894-1901(薛海红,王群勇,陈冬梅,等.航空电子设备NSEE试验评价方法[J].北京航空航天大学学报,2015,41(10):1894-1901)
[3] MERTENS C J, TOBISKA W K, BOUWER D, et al.Development of the nowcast of atmospheric ionizing radiation for aviation safety(NAIRAS)model[C]//1st AIAA Atmospheric and Space Environments Conference. San Antonio, Texas:AIAA, 2009:3633-978
[4] SATO T. Analytical model for estimating terrestrial cosmic ray fluxes nearly anytime and anywhere in the world:extension of PARMA/EXPACS[J]. Plos One,2015, 10(12):e0144679
[5] NESTERENOK A. Numerical calculations of cosmic ray cascade in the Earth's atmosphere results for nucleon spectra[J]. Nucl. Inst. Meth. Phys. Res.:B, 2013,295:99-106
[6] CAI Minghui, HAN Jianwei, LI Xiaoyin, et al. A simulation study of the atmospheric neutron environment in near space[J]. Acta Phys. Sin., 2009, 58(9):6659-6664(蔡明辉,韩建伟,李小银,等.临近空间大气中子环境的仿真研究[J].物理学报,2009, 58(9):6659-6664)
[7] TYLKA A J, ADAMS J H, BOBERG P R, et al.CREME96:a revision of the cosmic ray effects on microelectronics code[J]. IEEE Trans. Nucl. Sci., 2002,44(6):2150-2160
[8] O'NEILL P M,GOLGE S,SLABA T C. Badhwar-O'Neill2014 Galactic Cosmic Ray Flux Model Description, TP-2015-218569[R]. NASA Technical Report, 2015
[9] XAPSOS M A, BARTH J L, STASSINOPOULOS E G,et al. Characterizing solar proton energy spectra for radiation effects applications[J]. Nucl. Sci. IEEE Trans.,2000, 47(6):2218-2223
[10] THEBAULT E, FINLAY C C, BEGGAN C D, et al. International geomagnetic reference field:the 12th generation[J]. Earth Planets Space, 2015, 67(1):1-19
[11] TSYGANENKO N A, MAGNETOSPHERIC A. Magnetic field model with a warped tail current sheet[J]. Planet.Space Sci., 1989, 37(1):5-20
[12] TSYGANENKO N A, STERN D P. Modeling the global magnetic field of the large-scale Birkeland current systems[J]. J. Geophys. Res. Space Phys., 1996, 101(A12):27187-27198
[13] TSYGANENKO N A, SITNOV M I. Modeling the dynamics of the inner magnetosphere during strong geomagnetic storms[J]. J. Geophys. Res. Space Phys., 2005,110(A3):A0320
[14] TSYGANENKO N A. TS05-Data-and_Stuff[EB/OL].[2018-06-11]. http://geo.phys.spbu.ru/~tsyganenko/TS-05-data_and_stuff
[15] ZHEN Jie, CHU Wei. Numerical computation of proton geomagnetic vertical cutoff rigidities on 7—8 November2004[J]. Chin. J. Space Sci., 2013, 33(3):250-257(甄杰,楚伟.质子地磁垂直截止刚度在2004年11月7—8日两个时刻处的数值模拟[J].空间科学学报,2013, 33(3):250-257)
[16] DESORGHER L, FLUECKIGER E O, BUETIKOFER R, et al. Geant4 application for simulating the propagation of cosmic rays through the Earth's magnetosphere[C]//International Cosmic Ray Conference, 2003.DOI:10.5140/JASS.2011.28.2.117
[17] PICONE J M, HEDIN A E, DROB D P, et al.NRLMSISE-00 empirical model of the atmosphere:statistical comparisons and scientific issue[J]. J. Geophys.Res., 2002, 107(A12):1468
[18] ASAI M, DOTTI A, VERDERI M, et al. Recent developments in Geant4[J]. Ann. Nucl. Energy, 2015, 82:19-28
[19] LIN Z W, ADAMS J H, BARGHOUTY A F, et al. Comparisons of several transport models in their predictions in typical space radiation environments[J]. Adv. Space Res.,2012, 49(4):797-806
[20] DIETZE G, BARTLETT D T, COOL D A, et al. ICRP PUBLICATION 123:assessment of radiation exposure of astronauts in space[J]. Ann. ICRP, 2013, 42(4):1-3