Skip to Main content Skip to Navigation
Theses

Mesure Précise du Rendement Absolu de la Fluorescence de
l'Azote dans l'Air.
Conséquences sur la Détection des Rayons Cosmiques d'Ultra-Haute Énergie

Abstract : 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 either by sampling particle on the ground, or by detecting the fluorescence induced by the excitation of nitrogen by shower electrons. At present, the measurement of the fluorescence is the simplest and the most reliable method, since it does not call upon hadronic physics laws at extreme energies, a field still inaccessible to accelerators. 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. This main goal of this work is to measure this yield to better than 5 %. To do this, ~1 MeV electrons from a radioactive source excite nitrogen of the air. The accuracy has been reached thanks to the implementation of a new method for the absolute calibration of the photomultipliers detecting the photons, to better than 2 %. The fluorescence yield, measured and normalized to 0.85 MeV, 760 mmHg and 15°C, is
4.23 ± 0.20 photons per meter,
or 20.46 ± 0.98 photons per deposited MeV.
In addition, and for the first time, the absolute fluorescence spectrum of nitrogen excited by a source has been measured with an optical grating spectrometer.
Complete list of metadatas

Cited literature [21 references]  Display  Hide  Download

https://tel.archives-ouvertes.fr/tel-00112125
Contributor : Simone Lantz <>
Submitted on : Tuesday, November 7, 2006 - 3:32:01 PM
Last modification on : Wednesday, October 21, 2020 - 4:32:12 PM
Long-term archiving on: : Tuesday, April 6, 2010 - 9:46:04 PM

Identifiers

  • HAL Id : tel-00112125, version 1

Citation

Gwenaëlle Lefeuvre. Mesure Précise du Rendement Absolu de la Fluorescence de
l'Azote dans l'Air.
Conséquences sur la Détection des Rayons Cosmiques d'Ultra-Haute Énergie. Cosmologie et astrophysique extra-galactique [astro-ph.CO]. Université Paris-Diderot - Paris VII, 2006. Français. ⟨tel-00112125⟩

Share

Metrics

Record views

736

Files downloads

1592