GAMMA Experiment Primary energy spectra in the 1

GAMMA Experiment Primary energy spectra in the 1 -100 Pe. V energy range: GAMMA Experiment 4 Y. Gallant, 1 A. Garyaka, 5 L. Jones, 1 R. Martirosov, 2 N. Nikolskaya, 3 J. Procureur, 1 S. Ter-Antonyan Yerevan Physics Institute 2 Moscow Physics Institute 3 Centre d Etudes Nucleaires Bordeaux-Gradignan, 4 Universite Montpellier II 5 University of Michigan 1 1/2/2022 1

GAMMA Experiment GAMMA Facility • Location: Armenia, Mt. Aragats 3200 m a. s. l. • EAS array: 33 x 3 (1 x 1 x 0. 05)m 3+ +9(0. 3 x 0. 05) m 3 • Muon hall: 2500 g/cm 2 of rock 150 (1 x 1 x 0. 05)m 3 1/2/2022 • EAS data: Nch > 5 105 (100%) R < 25 m (50 m) < 300 N (R <50 m) > 103 E > 5 Ge. V T = 6. 2 107 sec 2

GAMMA Experiment Measurement errors: at EAS simulations: 1/2/2022 CORSIKA 6. 031(EGS, NKG) A SIBYLL 2. 1 QGSJET 01 Emin [Pe. V] P 1. 0· 105 0. 5 He 7. 1· 104 6. 0· 104 0. 7 O 4. 6· 104 4. 4· 104 1. 0 Fe 4. 8· 104 4. 0· 104 1. 2 Emax = 5· 103 Pe. V < 300 = -1. 5 Ee, > 1 Me. V E > 150 Me. V E > 4 Ge. V (e ) 3

Detector response Ø s(7 m < ri < 90 m) 1/2/2022 4

Particle density spectra Single particle spectra 15 detectors 1/2/2022 5

EAS Inverse Problem: 1) 1 -2 D Combined Analysis, nd. f. = 350 2) 2 D-Analysis, F(X) d 2 F/d. Ned. N , nd. f. = 240 1/2/2022 3) 4 D-Analysis, F(X) d 4 F/d. Ned. N ds dcos , nd. f. = 1640 6

Primary energy spectra Results of 1 -2 D Combined Analysis 1 = 0. 095 0. 008 [m-2 s-1 sr-1 Te. V-1] 2 = 0. 10 0. 012 3 -16 = 0. 043 0. 007 ( O - like ) 17 -26 = 0. 024 0. 004 ( Fe - like ) ER = 2500 200 TV 2/nd. f. 2. 0 1/2/2022 B. Wiebel & P. Biermann, 24 th ICRC (1995) A. Lagutin et al. , 29 th ICRC (2005) 7

Verification Test of KASCADE primary energy spectra by GAMMA EAS data WZ(E, X) f. Z(E) d. E = F(X) z Ø fp , f. He , f. O=f. C+f. Si , f. Fe Enlarged EAS data (R<50 m) 1/2/2022 Knee positions 8

GAMMA Experiment Conclusion Ø The obtained primary energy spectra strongly depend on interaction model. Ø The SIBYLL interaction model is more preferable. Ø Rigidity-dependent spectra describe the EAS data at least up to E~100 Pe. V. ØAll-particle primary energy spectra slightly depend on interaction model. ü The energy spectra of primary nuclei disagree with the same KASCADE data in 1 -100 Pe. V energy range, however, the discrepancies of the all-particle energy spectra obtained by the GAMMA and KASCADE are sufficiently small (~20%). 1/2/2022 9