Measurements of cosmic ray particles in the energy range of – eV in the PAMELA experiment 21 st European Cosmic Ray Symposium, Ko š ice, Slovakia September 2008 A.N. Kvashnin, on behalf of PAMELA collaboration

Trk, Sign of charge, rigidity, dE/dx. Electron energy, dE/dx, lepton-hadron separation e-e- p - e+e+ p (He,…) Trigger, ToF, dE/dx + GF ~21.5 cmsr, Mass: 470 kg Size: 130x70x70 cm GF ~21.5 cm 2 sr, Mass: 470 kg Size: 130x70x70 cm 3 For the search of high energy particles in PAMELA experiment we have used the data from Tracker, CALO, and ND detectors

We study high energy cosmic rays, namely, cosmic ray spectra of all particles, protons, helium nuclei, and electrons in the energy region of – ~10 14 eV. Method: In this work data of the tracker (G = 21 cm 2 sr ) and calorimeter are utilized (G cal = 470 cm 2 sr).

We calculated the expected number of events in the combination calorimeter + tracker per one year (G = 21 cm 2 sr) Energy, TeV > 0.1>1.0> 5> 10 Protons, interacted in 5 top layers (3.76 X-units) Electrons

Expected number of events per one year only in the calorimeter (G = 470 cm 2 sr) Energy, TeV > 0.1>1.0> 5> 10 Protons, interacted in 5 top layers (3.76 X-units) Electrons

To approximate cascade in CALO we have used the following expression: N(x) = N m exp[- (x – x m ) 2 /(d(x + kx m ))], where d and k are parameters (C. Song for HIREs collaboration. Study of the longitudinal development of air shower with CORSICA. Proc. of ICRC, 2001, Hamburg, Germany, HE, ).

K = 0.85 d = (44.5 – 43.5) g/cm 2 This expression describes calculated cascade curves very well.

k 1 = k 2 = 0.85 d 1 = ( ) g/cm 2 d 2 = ( ) g/cm 2 The special program was developed by our colleague Igor Nikitin to analyze longitudinal and transverse distribution of cascade particles.

Q tot =138E 0 R 2 =0.72

Thank you!

electrons

PAMELA collaboration Moscow St. Petersburg Russia: Sweden: KTH, Stockholm Germany: Siegen Italy: BariFlorenceFrascatiTriesteNaplesRome CNR, Florence

Grigorov N.L., Cosmic Research, 1995, v. 33, p. 339 Дж. Адамс, Зацепин В.И. И др., Изв. АН, сер. Физ., 1997, т. 61, стр ТУС Adams J., Zatsepin V.I. et al. Izv. RAS, ser. fiz., 1997, v. 61, p. 1181

Proton spectrum Curves are approximations: J p (E)=A(0.1/E) /[1+(E/a)  /2], where 1 – а = 1.5 TeV,  = 0.7; 2 - а = 0.7 TeV,  = 0.5;

(dE/dt) = E 0 b[(bt) a-1 ]*exp(-bt)/Г(a), where t is the radiation length, E 0 is the total cascade energy, b and a are parameters, defined as [(a-1)/b] = ln (E o /E c ) + C, E c is critical energy, equal to 7.97 MeV, С = for a cascade from electron, С = 0.5 for a cascade from gamma ray, Г(a) is the gamma-function. (The European Physical Journal C15, (2000); Review of Particle Physics).

Каскадная кривая для протонов N(x) = N 1m exp[- (x – x 1m ) 2 /(d 1 (x + k 1 x 1m ))] + N 2m exp[- (x – x 2m ) 2 /(d 2 (x + k 2 x 2m ))], где d 1, d 2 и k 1, k 2 – параметры (C. Song for HIREs collaboration. Study of the longitudinal development of air shower with CORSICA. Proc. of ICRC, 2001, Hamburg, Germany, HE, ).

k = 0.83 d = 2 g/cm 2

k = 0.83 d = 2 g/cm 2

k = 0.83 d = 2 g/cm 2