1. Exploring Laser Light Ruben Conceição

2. Pierre Auger Observatory Ultra High Energy Cosmic Rays Pierre Auger Observatory – Fluorescence Detector Longitudinal Profile Fluorescence light – Surface Detector Ground charged lateral distribution Ruben Conceição2Sesimbra, IDPASC 2010

3. Following the light FD Point Spread Function Multiple Scattering  Ruben Conceição3Sesimbra, IDPASC 2010

4. Zeta Measuring the differential light profiles Angular distance to spot center: – Zeta (  ) Evaluate – By using – Measured in each pixel i Average many profiles to reduce statistical fluctuations – Need to control Event similarity Clouds Undershooting Applicable in full camera acquisition or in a band! CLF shot seen at LL with full camera aquisition Ruben Conceição4Sesimbra, IDPASC 2010

5. CLF @ Coihueco Light lateral profile vs. angular distance to spot center (zeta) Direct light  Detector PSF Multiple Scattering

6. CLF @ Coihueco Total light vs. elevation angle  (several millions CLF shots) Mie Rayleigh The shape of the light profile is sensitive to VAOD

7. Geant4 Laser Simulation Photon tracking in the atmosphere done with Geant4: – Rayleigh scattering – Mie scattering Layers with constant depth (20 g/cm2) Different atmospheric profiles Detectors implemented as cone sections, 2 m height to simulate camera aperture and inclination. Can suffer any number of Mie or Rayleigh scatterings Comparison between data and simulation Ruben Conceição7Sesimbra, IDPASC 2010

8. Conclusions Powerful tools for understanding the multiscattered light – Further studies to check the dependency with altitude, time of arrival and distance can be done First data/MC comparison results are encouraging – Reasonable agreement The detector PSF can be acquired up to 10 -4 of maximum signal

9. BACKUP Ruben Conceição9Sesimbra, IDPASC 2010

10. CLF @ Los Leones Ruben Conceição10Sesimbra, IDPASC 2010