Multiple scattering measurement with laser events

Assis, P.; Conceição, R.; Gonçalves, P.; Pimenta, M.; Tomé, B.; the Pierre Auger Collaboration,

doi:doi:10.5194/astra-7-383-2011

Astrophys. Space Sci. Trans., 7, 383-386, 2011
www.astrophys-space-sci-trans.net/7/383/2011/
doi:10.5194/astra-7-383-2011
© Author(s) 2011. This work is distributed
under the Creative Commons Attribution 3.0 License.

Volume 7, issue 3

09 Sep 2011

Multiple scattering measurement with laser events
P. Assis¹, R. Conceição¹, P. Gonçalves¹, M. Pimenta^1,2, B. Tomé¹, and the Pierre Auger Collaboration³
¹LIP, Av. Elias Garcia, 14-1, 1000–149 Lisbon, Portugal
²Departamento de Física, IST, Av. Rovisco Pais, 1049-001 Lisbon, Portugal
³Observatorio Pierre Auger, Av. San Martin Norte 304, (5613) Malargüe, Mendoza, Argentina (Full author list: http://www.auger.org/archive/authors_2010_08.html)

Received: 14 Nov 2010 – Revised: 15 May 2011 – Accepted: 16 Jun 2011 – Published: 09 Sep 2011

Abstract. The Pierre Auger Observatory Fluorescence Detector (FD) performs a calorimetric measurement of the primary energy of cosmic ray showers. The level of accuracy of this technique is determined by the uncertainty in several parameters, among them the fraction of shower light (both from fluorescence and Cherenkov light) that reaches the detector after being multiply scattered (MS) in the atmosphere. This component depends on atmospheric conditions, namely on Rayleigh and Mie scattering processes. Using laser events it is possible to study these processes and deconvolute them from the shower's electromagnetic lateral distribution.

We propose a new method to measure the Rayleigh and Mie MS components seen in laser events, and correlate them with atmospheric conditions. In order to study in detail the effect of such conditions in the scattering of photons, a Geant4 dedicated laser simulation was developed. % In this framework photons are individually followed through the atmosphere allowing for any number of scatterings, from both processes This combination of a MS dedicated data analysis with a realistic laser simulation enables to explore MS characteristics, in particular the evolution with time, altitude and distance from the FD.

Citation: Assis, P., Conceição, R., Gonçalves, P., Pimenta, M., Tomé, B., and the Pierre Auger Collaboration: Multiple scattering measurement with laser events, Astrophys. Space Sci. Trans., 7, 383-386, doi:10.5194/astra-7-383-2011, 2011.

Astrophysics and Space Sciences Transactions

An Open Access Journal of the Arbeitsgemeinschaft Extraterrestrische Forschung e.V.