Particle Physics Seminar

"Measurement of the Fluorescence Yield for the Ultra-High Energy Cosmic Ray Study"

Presented by Gwenaelle Lefeuvre, Astroparticules et Cosmologie

Thursday, November 16, 2006, 3:00 pm — Small Seminar Room, Bldg. 510

The study of the energy spectrum of ultra-high energy cosmic rays (E > 1020 eV) requires to determine the energy with much more precision than what is currently achieved. The shower of particles created in the atmosphere can be
detected thanks to the fluorescence induced by the excitation of nitrogen by shower electrons. The precise knowledge of the conversion factor between deposited energy and the number of fluorescence photons produced (the yield)
is thus essential. Up to now, it has been determined with an accuracy of 15 % only. I will explain how it has been possible to measure the fluorescence yield to better than 5 %. Among other things, the accuracy has been reached
thanks to the implementation of a new method for the absolute calibration of the photomultipliers detecting the photons.

Hosted by: David Jaffe

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