Vladimir Mikhailov (NRNU MEPHI, Moscow) On behavior PAMELA collaboration SUB CUTOFF SPECTRA OF ELECTRONS AND POSITRONS measured in the PAMELA experiment

O. Adriani c, G.C. Barbarino g, G.A. Bazilevskaja l, R. Bellotti j, M. Boezio e, E.A. Bogomolov k, L. Bonechi c, M. Bongi c, V. Bonvicini e, S.V. Borisov b, S. Bottai c, A. Bruno j, F. Cafagna j, D. Campana g, R. Carbone g, P. Carlson f, M. Casolino a, G. Castellini d, L. Consiglio g, M.P. De Pascale a, C. De Santis a, N. De Simone a, V. Di Felice a, A.M. Galper b, L.A. Grishantseva b, W.Gillard f, G. Jerse e, A.V. Karelin b, S.V. Koldashov b, S.Yu. Krutkov k, A.N. Kvashnin l, A.A. Leonov b, V.V. Malakhov b, L. Marcelli a, A.Mayorov b, W. Menn h, V.V. Mikhailov b, E.Mocchiutti e, A. Monaco j, N. Mori c, N.N. Nikonov k, G. Osteria g, P. Papini c,F.Palma, M. Pearce f, P. Picozza a, C. Pizzolotto e, M. Ricci i, S.B. Ricciarini c, L. Rossetto f, M.F. Runtso b, S. J. Stochaj e,M. Simon h, R. Sparvoli a, P. Spillantini c, Yu.I. Stozhkov l, A. Vacchi e, E. Vannuccini c, G.I. Vasiliev k, S.A. Voronov b, G. Wu f, Y.T. Yurkin b, G. Zampa e, N. Zampa e, V.G. Zverev b a - INFN, Structure of Rome “Tor Vergata” and Physics Department of University of Rome “Tor Vergata” Rome, Italy b - Moscow Engineering and Physics Institute, Moscow, Russia c - INFN, Structure of Florence and Physics Department of University of Florence, Florence, Italy d - IFAC, Florence, Italy e - INFN, Structure of Trieste and Physics Department of University of Trieste, Trieste, Italy f - KTH, Department of Physics, Stockholm, Sweden g - INFN, Structure of Naples and Physics Department of University of Naples, Naples, Italy h – University at Siegen, Siegen, Germany i- INFN, Laboratori Nazionali di Frascati, Frascati, Italy j - INFN, Structure of Bari and Physics Department of University, Bari, Italy k - Ioffe Physical Technical Institute, St. Petersburg, Russia l - Lebedev Physical Institute, Moscow, Russia

Secondary production in residual atmosphere and results of old experiments CR proton Interaction point Secondary positron Production of charged pions in CR protons interaction with residual atmosphere      е  и  0  2  е + + е - Trapping of secondary particles, live time T(h) Intensity (h) ~Icr ·  (h)·T(h)~  ·1/  constant (h) Total electron &positron flux measured in equatorial region Rcut>10GV before 1999 N. Grigorov Possibility of existence of a radiation belt around the earth consisting of electr.ons with energies of 100 MeV and above. Soviet Physics Doklady, Vol. 22, p.305, 1977 The cosmic ray intensity above the atmosphere (Phys Rev. 75, 1, 1949) “Secondaries emerging from the atmosphere and executing orbits in the Earth’s magnetic field undoubtedly contribute in (…) intensity above t he atmosphere” OSO-3 measurements of atmospheric gamma rays (ApJ,1972,177,341)

PAMELA is here Satellite was launched on elliptical polar orbit with inclination 70 0, altitude km. More then 20TB data were gathered in 5 Years

Main object of PAMELA magnetic spectrometer is detail investigation of energy spectra antiparticles in cosmic rays in energy interval 50 MeV – 300 GeV MDR ~ 1TeV Calorimeter ~ 16Xo Geomfactor= 21.6 cm 2 sr Livetime ~ 5years Calorimeter+ToF+tracker selection provide rejection factor ~ See papers E. Mocchiutti ID815, L. Rossetto ID 667 for more details PAMELA instrument

Satellite ResursDK №1 has elliptical orbit : km with inclination ~70 0. The instrument is pointed to zenith mainly. Attitude information fixed every 30 sec. For every event geographic and geomagnetic coordinates are calculated. Pitch-angle of every events calculated using IGRF model and direction inside the instrument Count rate of top PAMELA counter: low energy ~MeV protons rate. Polar region, Equatorial region and South Atlantic Anomaly (SAA) are clearly seen Altitude of geomagnetic field lines, L-shell =1.12 PAMELA IS HERE

Study terrestrial magnetosphere Spectra of protons Secondary re-entrant- albedo protons Magnetic polar cups (  galactic protons) Geomagnetic cutoff Trapped protons in SAA. See more in F.Cafagna, ID963

Primary CR Secondary CR Equatorial region, Geomagnetic latitude  <0.3. Data of 2006

Pamela and AMS measurements. AMS flew on-board the Space Shuttle during decade in Inclination ~56 0, altitude ~400km ( Phys. Lett. B –22) e-e- e+e+

Latitudinal behavior of electron/positron spectra Positrons Positron flux, 1/(m 2 s sr MeV ) GeV Electrons Electron flux, 1/(m 2 s sr MeV) GeV flux, 1/(m 2 s sr MeV) electrons positrons GeV L-shell flux, 1/(m 2 s sr MeV) electrons positrons GeV L-shell

M. Honda (2009) Calculated energy spectra at 550km for vertical cut-off 0 – 0.6, ,1 – 1.5, , 2 – 4, 4 – 7, 7 – 10, 10 – 14 GV 10 – 14 GV 4-7 GV

Positron to electron ratio in equatorial region Primary component East-west effect Rigidity cut off from East direction is ~60GV due to shadow of the Earth, from West direction ~10GV. => source of secondary electrons is supressed, e+/e- ratio is high Fig. modified from

Positron to electron ratio in equatorial region Pitch-angle distributions of ratios

Longitudinal behavior of electron/positron spectra Electron flux, 1/(m 2 s sr MeV) 0-40 Longitude, degree GeV

Observation at L 0.24Gs (equatorial subcut-off data) and B<0.21Gs (SAA data) Calculated spectra of trapped electrons and positrons from Gusev et al, 2002 Earth Planets Space

Conclusion 1.Subcutoff electron and positron fluxes were measured by the PAMELA experiment with high accuracy from 100MV to cutoff Rigidity 2. Electron and positron fluxes have a complex structure depending from direction, energy, latitude and longitude. 3.New data might be useful to tune models of secondary production

Thank you !

 Proton spectra since August 2006 till September of 2009 effect of solar modulation is visible.  Low energy proton intensity is increasing with time The changes of solar modulation parameter since till Galactic proton spectra

 Primary component was increasing in time during  Secondary electrons and positrons are practically constant. small variations of counting rate are possible due to orbit rotation : mean Lshell and pitch-angle  secondary primary Fluxes are normalized to September 2006