1. Contribution of simulation techniques to the space weather research Pavlos Paschalis [1] H. Mavromichalaki[1], L.I. Dorman[2], Ch. Plainaki[3] [1] Athens Cosmic ray Team, Physics Faculty, National and Kapodistrian University of Athens [2] Tel-Aviv University, Israel [3] INAF-IFSI, Rome, Italy 12 th European Space Weather Week 23-27 November 2015, Ostend, Belgium ppaschalis@phys.uoa.gr http://cosray.phys.uoa.gr National and Kapodistrian University of Athens Physics Faculty Athens Cosmic Ray Team

2. 12 th European Space Weather Week 23-27 November 2015, Ostend, Belgium Overview Basics of Geant4 Conclusions and Future Plans Simulation of Neutron Monitor Simulation of atmospheric showers Simulation Techniques

3. 12 th European Space Weather Week 23-27 November 2015, Ostend, Belgium Simulation Techniques a few on NMs most on cosmic ray showers most based on Geant4 and FLUKA toolkits Well known works and applications CORSIKA: Simulation of cosmic ray showers Karlsruhe Institute of Technology (D. Heck, J. Knapp, J.N. Capdevielle, G. Schatz, T. Thouw) ATMOCOSMICS-MAGNETOCOSMICS-PLANETOCOSMICS: Simulation of cosmic rays in the atmosphere, magnetosphere and at other planets University of Bern (L. Desorgher, M. Gurtner, and E.O. Flückinger, M.R. Moser, R. Bütikofer) CRII: Calculation of ionization in the atmosphere University of Oulu (I.G. Usoskin, G.A. Kovaltsov, I.A. Mironova) Simulation of NMs and cosmic ray showers ( Clem and Dorman, Space Science Rev., 2000) Several works/publications

4. 12 th European Space Weather Week 23-27 November 2015, Ostend, Belgium Geant4 Collection of classes User defined classes GeometryBeamPhysics Access to particles and parameters during simulation (Agostinelli et al. for GEANT4 Collaboration, NIM A, 2003) (Allison et al. for GEANT4 Collaboration, IEEE, 2006) C++ toolkit MandatoryOptional

5. 12 th European Space Weather Week 23-27 November 2015, Ostend, Belgium Atmospheric Shower Simulation

6. 12 th European Space Weather Week 23-27 November 2015, Ostend, Belgium Atmospheric Shower Simulation Aim determination of various parameters of the cascade development of a stand alone application DYASTIMA DYnamic Atmospheric Shower Tracking Interactive Model Application (P. Paschalis, H. Mavromichalaki, L.I. Dorman, C. Plainaki, D. Tsirigkas, New Astron. 2014) User friendly input of the necessary parameters Handling of the huge amount of output information Simulation.CSV files Graphical User Interface (.NET) optimal storage resume of the simulation multithread simulation easy set up of simulation parameters storing of several simulation scenarios setting up of Geant4 and environmental parameters Challenging points

7. 12 th European Space Weather Week 23-27 November 2015, Ostend, Belgium Geometry Beam spectrum of each particle directional limits of each particle Data collection when a new particle is generated when a particle crosses a tracking layer energy cuts in production/simulation/tracking Interactions reference physics list appropriate for high energy physics Atmospheric Shower Simulation composition and temperature profile of the atmosphere parameters of the planet division of the atmosphere in slices flat/ spherical model magnetic field 1 GeV proton small shower 10 GeV proton Production of multiple particles Simulation Screenshot

8. 12 th European Space Weather Week 23-27 November 2015, Ostend, Belgium Particles @ Production time Altitude Energy max production at the height of ~10-15 Km similar spectra for protons-neutrons similar spectra for muons spectrum of electrons starts from low energies

9. Particles @ Tracking layer Direction Time Energy Ionization Position

10. 12 th European Space Weather Week 23-27 November 2015, Ostend, Belgium Agreement with other publications Vertical Flux in the Atmosphere vertical flux of particles with E>1 GeV results in accordance with other works Planet: Earth Atmosphere: International Standard Atmosphere Spectrum: Typical (Particle Data Group) Physics List: QGSP_BIC_HP Production Range cut: 1m

11. 12 th European Space Weather Week 23-27 November 2015, Ostend, Belgium DYASTIMA and Venusian Atmosphere Planet: Venus Atmosphere: Seiff et al., Adv. Space Res., 1985 von Zahn and Moroz, Adv. Space Res., 1985 Keating et al., Adv. Space Res., 1985 Spectrum: CRÈME (Tylka et al., IEEE Trans. on Nucl. Sci., 1997) NMBANGLE PPOLA (Plainaki et al. 2010; 2014) Physics List: FTFP_BERT_HP Production Range cut: 1m Results in accordance with other publications Maximum @ ~ 62-64 Km Increased ionization during Solar Minimum Same pattern for soft events – multiple magnitude Two orders of magnitude increase during intense events – maximum @ higher altitude

12. 12 th European Space Weather Week 23-27 November 2015, Ostend, Belgium Simulation of 6NM-64 Neutron Monitor

13. 12 th European Space Weather Week 23-27 November 2015, Ostend, Belgium Simulation of 6NM-64 Neutron Monitor Aim determination of the detection efficiency for various particles, angles and energies Geometry Instruction Manual Carmichael (1964) Beam Monoenergetic particles that illuminate whole or a part of the NM Interactions reference physics list appropriate for high energy physics accurate handling of neutrons Pulse determination Neutron captures in the tubes + counter resolving time + electronics dead time (P. Paschalis, H. Mavromichalaki, L. I. Dorman, NIM A, 2013) 1 GeV neutron a few secondary neutrons Simulation Screenshot 100 GeV neutron great increase of secondary neutrons

14. 12 th European Space Weather Week 23-27 November 2015, Ostend, Belgium Detection efficiency of particles Detection efficiency is increased for hadrons Results in accordance with Clem and Dorman (2000) In lower energies, the detection efficiency presents an increase over 50 MeV Low Energies High Energies

15. 12 th European Space Weather Week 23-27 November 2015, Ostend, Belgium Spatial and angular affection spatial affection angular affection azimuth perpendicular to the counters angular affection azimuth across the counters central region  significant detection edges  rapid reduce angle increase path through the NM increase detection efficiency increase over 80 o some particles pass through the tubes detection efficiency decrease

16. 12 th European Space Weather Week 23-27 November 2015, Ostend, Belgium Capture of neutrons low energies  all neutron captures are registered high energies  the dead time of electronics becomes significant ~4.5% of the secondary neutrons are captured in the tubes

17. 12 th European Space Weather Week 23-27 November 2015, Ostend, Belgium Future Plans Finalize the new version of DYASTIMA Further optimization of data handling and storage Enhance the simulations with new features Model the shower parameters regarding the spectra of the particles Transit to radiation dose calculation Develop a new version of NM simulation that can accept the output of DYASTIMA Conclusions Standalone applications that are easy to use by non experienced users Accurate results that are in agreement with other works Output information that can be used in several works

18. 12 th European Space Weather Week 23-27 November 2015, Ostend, Belgium References P. Paschalis, H. Mavromichalaki, L.I. Dorman, “A quantitative study of the 6NM-64 neutron monitor by using Geant4: 1. Detection efficiency for different particles”, NIM A, 729, 877-887, 2013 P. Paschalis, H. Mavromichalaki, L.I. Dorman, C. Plainaki, D. Tsirigkas, “Application for the cosmic rays simulation of atmospheric showers using Geant4”, New Astron., 33, 26-37, 2014 C. Plainaki, P. Paschalis, D. Grassi, H. Mavromichalaki, M. Andriopoulou, “Cosmic ray interactions with the Venusian atmosphere”, EGU2015-3945 L.I. Dorman, P. Paschalis, C. Plainaki, H. Mavromichalaki, “Estimation of the cosmic ray ionization in the Earth's atmosphere during GLE71”, Proc. 33 rd ICRC2015 S. Agostinelli, J. Allison, K. Amako, J. Apostolakis et al. [Geant4 Collaboration], “Geant4 - a simulation toolkit”, NIM A, 506, 250-303, 2003 J. Allison, K. Amako, J. Apostolakis, H. Araujo et al. [Geant4 Collaboration], “Geant4 developments and applications”, IEEE Trans. on Nucl. Sci., 53, 270-278, 2006