Measurements of electron and positron fluxes below the geomagnetic cutoff by the PAMELA magnetic spectrometer
V. Mikhailov, on behalf of the PAMELA collaboration, V. Mikhailov, O. Adriani, G.C. Barbarino, G.A. Bazilevskaya, R. Bellotti, M. Boezio, E.A. Bogomolov, M. Bongi, G. Bonvicini, S. Bottai, A. Bruno, F. Cafagna, D. Campana, P. Carlson, M. Casolino, G. Castellini, C. De Donato, C. De Santis, V. Di Felice, A.M. Galper, A.V. Karelin, S. Koldobskiy, S.V. Koldashov, S.Y. Krutkov, A.N. Kvashnin, A. Leonov, V. Malakhov, L. Marcelli, M. Martucci, A.G. Mayorov, M. Merge', Y.V. Mikhailova, E. Mocchiutti, A. Monaco, N. Mori, R. Munini, G. Osteria, B. Panico, P. Papini, M. Pearce, P. Picozza, M. Ricci, S.B. Ricciarini, M. Simon, R. Sparvoli, P. Spillantini, Y.I. Stozhkov, A. Vacchi, E. Vannuccini, G. Vasilyev, S.A. Voronov, Y.T. Yurkin, G. Zampa, N. Zampa
We present a measurements of electron and positron fluxes below the geomagnetic cutoff rigidity in wide energy range from ~50 MeV to several GeVs by the PAMELA magnetic spectrometer.
The instrument was launched on June 15th 2006 on-board the Resurs-DK satellite on low orbit with 70 degrees inclination and altitude between 350 and 600 km. Features of spatial distributions of secondary electrons and positrons in the near Earth space, including the South Atlantic Anomaly, were investigated in terms of lifetime and geographical origin. The separation in stably trapped , long lifetime quasi-trapped, and short lifetime albedo components was performed on base of back tracing procedure in geomagnetic field. A significant difference in relative abundance of positrons with respect to electrons is seen for the stable trapped and the quasi-trapped populations what pointing out on different trapping mechanism of those populations.