1 / 20

Cosmic rays above 10 17 eV; the highest energy particles

A Cross Check of Atmospheric Attenuation for the High Resolution Fly’s Eye Astroparticle Experiment Chris Cannon Advisor: Lawrence Wiencke University of Utah. Cosmic rays above 10 17 eV; the highest energy particles Atmospheric attenuation plays a significant role in detector calibration.

virgil
Download Presentation

Cosmic rays above 10 17 eV; the highest energy particles

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. A Cross Check of Atmospheric Attenuation for the High Resolution Fly’s Eye Astroparticle Experiment Chris Cannon Advisor: Lawrence Wiencke University of Utah • Cosmic rays above 1017 eV; the highest energy particles • Atmospheric attenuation plays a significant role in detector calibration. • Cross check atmospheric calibration • Results • Conclusion

  2. Cosmic Ray Energy Spectrum Flux E^3 Man-made accelerators At energies above 1020 eV the flux is extremely low!!! Namely 1 particle/km2-steradian/century

  3. Using the Atmosphere as a Detector

  4. Introducing High Resolution Fly’s Eye (HiRes)

  5. HiRes Camera Mirror PMT Cluster

  6. Display of a Sample Air Shower

  7. The Atmosphere – Two Components Vertical Aerosol Optical Depth (VAOD) is the optical thickness of the aerosol component of the atmosphere. Transmission(aerosol) = e-VAOD Aerosols Molecular

  8. Measuring VAOD with Atmospheric Lasers HiRes-2 laser system HiRes-1 detector 12.6 km Average VAOD: 0.04 +- .02

  9. Measuring VAOD with Cosmic Rays detector 2 Reality detector 1 Erroneous Simulation - Overcorretion apparent shower 2 apparent shower 1 apparent shower 2 Erroneous Simulation - Undercorrection apparent shower 1

  10. Data Selection • Start with 2079 cosmic rays seen by both detectors. • Require that: • The two detectors see a common portion of the shower. • Each detector must collect at least 1000 photons from the common track segment, which must be at least 5 degrees long. • The probability that the event is noise based on a random walk model is less than 5%. • The event is downward going. • The opening angle between shower-detector planes is greater than 25 degrees. • The scattering angle is at least 25 degrees. • 1218 cosmic ray events remain. Purpose of Cuts: Remove noisy, dim events. Ensure good geometry. Remove Cherenkov dominated events.

  11. Use the segment of the shower viewed by both detectors. Profile integration Luminosity (photons/m) Luminosity (photons/m) Distance from Gound (m) Distance from Gound (m)

  12. Plotting Data Greater distance brighter shower. The atmosphere is over-corrected. Difference in shower brightness - 0 + Greater distance dimmer shower. The atmosphere is under-corrected. - 0 + Difference in distance between detectors and shower

  13. Results Simulated Atmosphere Canonical Model Measured Average No Aerosols Comment Over-correction Under-correction

  14. Conclusion: VAOD Measurement Using cosmic rays .043 +- .001 (stat) Using lasers .04 +- .02

  15. Effect of Atmospheric Calibration 1999 2003 With Model Atmosphere With Measured Atmosphere

  16. Greisen-Zatsepin-Kuzmin (GZK) Cutoff Charged particles with E > 5 x 1019 eV will travel at most 100 Mpc before their energy drops below the cutoff.

  17. HiRes Atmospheric Works in Progress • Improved atmospheric monitoring: • Hourly aerosol corrections instead of average. • Cloud monitoring.

  18. Sources of Cosmic Rays • The Sun • Solar Wind • Low Energy < 10 GeV • Supernovae Capable of accelerating particles to 1015eV • AGNs / GRBs … Possible sources for UHECRs

  19. Requirements on acceleration size and field strength

  20. Geometry with One Eye shower Equal Angle Bins Rp ψ detector Use Timing…. Depth Perception is Limited Need to measure a change in angular velocity Works best with Longer track Larger Rp Smaller ψ

More Related