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Detection of UHE Shower Cores by ANITA
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Detection of UHE Shower Cores by ANITA

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  1. Detection of UHE Shower Cores by ANITA By Amir Javaid University Of Delaware

  2. Topics • Rough estimates for event rate & shower core analysis summary • Detection of Shower cores by ANITA • Brief look at the shower Cores • Summary of UD Monte Carlo Simulator for Shower core detection by ANITA • Present status of UD Monte Carlo • Some preliminary results from Monte Carlo Simulator test runs • Search for a better Model for Antarctic topography • Summary and future plans

  3. Rough estimates for event rate above 1019eV for ANITA • Air Showers For one steradian around the vertical axis the Event Rate estimated for ANITA payload horizon ~ 1.5×1016cm2from the measured cosmic ray flux data is ~1400 events per day[1]. • Neutrinos For 2 π steradian the Event Rate estimated for ANITA horizon from the Waxman Bahcall flux model is~237 interactions per day[1]. [1] ftp://ftp.bartol.udel.edu/anita/amir/EventRate_analysis_V1.4.pdf

  4. Detection of Shower cores by ANITA schematic

  5. Detection of Shower cores by ANITA • Energy in the Shower cores above 100PeV~10% (Corsika Shower Simulations) • Shower cores will produce Askaryan pulse. • Pulses may be strong enough to be detected by ANITA payload • Askaryan pulses moving downwards and reflecting back from the bed rock are the most favorable for detection • Regions with thin ice and high elevation are most suitable for shower core detection by ANITA. • Approximately 8% of the area in Antarctica has Ice thickness<1km & surface elevation >1km, which may be the region to look for shower core events

  6. Detection of Shower cores by ANITA (contd ..) Area suitable for Shower core detection ~8% Ice thickness Histogram (Bedmap)

  7. Brief look at the shower Cores • To analyze the properties of the shower cores a library of Corsika shower runs has been generated • Present energy span of this library is from 10PeV -1EeV • The detector elevation is set at the South Pole and zenith angle is chosen to be zero • Showers are produce in South Pole magnetic field • Flat detector and curved atmosphere model is used.

  8. 1 EeV primary proton shower footprint at South Pole for 10m2 area Brief look at the shower Cores (Corsika Simulation runs)

  9. Brief Look at the shower Cores (contd..) 1 EeV primary proton shower footprint at South Pole for 1m2 area

  10. Brief Look at the shower Cores (contd..) 1 EeV primary proton shower footprint at South Pole for 10cm2 area

  11. Brief look at the shower cores (contd ..) 150 PeV ~15% of Total Shower

  12. Present Status of UD Monte Carlo Simulator • UD MC is in testing Stage. • It is based on the SADE0.1 MC by Shahid Hussain modified to fit the ANITA event Geometry. • For testing purpose AVZ parameterized Askaryan pulses are used. • It uses Bedmap for ice thickness, bedrock elevation and surface elevation. • Interpolation is used to fill the gaps in Bedmap data. • For testing purpose Snell’s law with constant refractive of ice for ray tracing is used.

  13. Present Status of UD Monte Carlo Simulator (contd ..) • More sophisticated ray tracing techniques do exist in UD MC. • It assumes that the ice and bedrock surfaces are flat. Perfect reflection from bedrock and perfect transmission from ice/air surface. • Point detector model with orientation. • Constant attenuation model for testing purpose. • More realistic attenuation models are also built in UD MC.

  14. Xperp Altitude depth Rbn Preliminary Results (UD MC) Xparallel • Test Run geometry • Detector position Latitude=-79.2993 deg Longitude=-90o deg, Altitude=36986.5m • Event position & Energy Latitude=-78 deg, Longitude=-90 deg, depth=198.3m Energy=100PeV, Cherenkov Angle=55.85 deg • Test runs Red Arrows show various shower axes used to test the code Event Vertex Shower axes

  15. Test Run Results (contd..)

  16. Test Run Results (contd..)

  17. Test Run Results (contd..)

  18. Search for a better Model for Antarctic topography • For modeling of the surface and bedrock roughness much high resolution Antarctic topographical models are needed. • One option is the Radarsat Antarctic Mapping (RAMP) Project Digital Elevation Model Version 2 available from The National Snow and Ice Data Center. • RAMP 1 km, 400 m, and 200 m DEM data are provided in ARC/INFO and binary grid formats, and the 1 km and 400 m DEMs are also available in ASCII format.

  19. Search for a better Model for Antarctic topography (contd..)

  20. Search for a better Model for Antarctic topography (contd..) Radarsat Surface elevation 400mRes Bedmap Surface elevation 5km Res

  21. Summary and Future Plans • Development of parameterization of Askaryan pulses from shower cores. • Use of Fresnel reflection and transmission in UD MC • Realistic Detector and triggering model. • Effective area calculation • Feasibility check of the Radarsat RAMP data for the use in Monte Carlo for modeling surface roughness for bedrock and ice/air surface. These files are large (~2.5 GB), which mean more cpu cycles are required • Plan of ANITA -1 flight data analysis for shower core events.