Seminars and Colloquia
Fermi-LAT measurement of Cosmic-Ray positron spectrum using the Earth's magnetic field
by
→
Europe/Rome
131 (INFN Edicifio C)
131
INFN Edicifio C
Description
With a precise measurement of the combined Cosmic-Ray electron and positron spectrum, the Fermi Large Area Telescope (LAT) has proven to be an excellent electron detector.
Being a purely calorimetric experiment, the LAT is not capable to directly distinguish particle charge.
However, we can exploit the Earth's magnetic field to effectively separate negatively and positively charged particles.
With the aid of a precise tabulation of the geomagnetic field, we are able to predict trajectories of particles in this field and use this information to discriminate between positrons and electrons.
In this talk we present the details of this analysis together with the preliminary results on the positron and electron spectra for energies greater than 20 GeV. The derived positron fraction will be also discussed.