INTEGRAL Satellite on Oct 28th 2003

INTEGRAL Satellite on Oct 28th 2003

Tsumeb, Namibia 17.6E, 19.1S, 1240m, Air mass : 890 g/cm2 Conditions at the event time 　・ Zenith angle : 9.5° 　・ Air mass : 902 g/cm2

Tsumeb Neutron Monitor on Oct 28th 2003 6.4σ Excesses were seen between 11:05 – 11:15UT. The statistical significance for 10 minutes is 6.4σ. Assuming that the solar neutrons were produced at 11:05UT, the energy of solar neutrons were >100MeV. Calculate the energy spectrum of solar neutrons (solar surface) ・ Attenuation : Shibata Program (Shibata et al., 1994) ・ Detection Efficiency of NM : Clem & Dorman (2000)

solar neutrons (>100MeV) : 3.1×1025 [erg/sr] Neutron Spectrum on Oct 28th 2003 (Tsumeb NM) Power index = – 3.6 ± 0.3 Flux @ 100MeV = (3.1 ± 1.0)×1027 [/MeV/sr] Total energy flux of solar neutrons (>100MeV) : 3.1×1025 [erg/sr]

Solar neutrons were produced at INTEGRAL Satellite on Nov 4th 2003 Peaked at 19:45UT ⇒ Solar neutrons were produced at 19:45UT

Haleakala, Hawaii 2003/11/4 19:45UT ・ Zenith angle : 50.5° 203.7E, 20.7N, 3030m, 707 g/cm2 18m2 Neutron Monitor 2003/11/4 19:45UT ・ Zenith angle : 50.5° ・ Air mass : 1112 g/cm2 Mexico City, Mexico 260.8E, 19.3N, 2274m, 780 g/cm2 4m2 Solar Neutron Telescope 2003/11/4 19:45UT ・ Zenith angle : 40.5° ・ Air mass : 1026 g/cm2

Neutron Monitor on Nov 4th 2003 5.3σ Clear excesses were seen between 19:46 – 20:01 UT 7.5σ Clear excesses were seen between 19:45 – 20:00 UT 3.3σ 5.2σ

Haleakala Neutron Monitor on Nov 4th 2003 5.3σ Clear excesses were seen between 19:46 – 20:01UT. The statistical significance for 15 minutes is 7.5σ. Assuming that the solar neutrons were produced at 19:45UT, the energy of solar neutrons were 59 – 913MeV. Assuming that the solar neutrons were produced at 19:45UT, the energy of solar neutrons were 59 – 913MeV. Solar neutrons in this energy range can penetrate to the ground through the earth’s atmosphere. From the time profile of the neutrons, we have calculated the energy spectrum of solar neutrons at the solar surface using Shibata program and the efficiency of neutron monitor calculated by Clem. Calculate the energy spectrum of solar neutrons (solar surface) ・ Attenuation : Shibata program (Shibata et al., 1994) ・ Detection Efficiency of NM : Clem & Dorman (2000)

Neutron Spectrum on Nov 4th 2003 (Haleakala NM) Power index = – 3.9 ± 0.5 Flux at 100MeV = (1.5 ± 0.6)×1028 [/MeV/sr] (χ2/dof = 0.92/3 = 0.31) Assuming that solar neutrons were produced at 19:45UT, the energy spectrum of solar neutrons produced at the solar surface is well fitted by a power law with index –3.9. (The total energy flux of solar neutrons detected between 59 and 913MeV is 3.4 times 10 to the 26 erg/sr.) This power index is typical value for solar neutron events observed thus far. In this calculation, we assumed that solar neutrons were produced at the peak time of gamma-rays, however, gamma-rays were emitted for 4 minutes. Thus we simulated the time profile of solar neutrons at the neutron monitors assuming that solar neutrons were produced with the same time profile as the gamma-ray emission. Total energy flux of solar neutrons (59 – 913MeV) : 3.4×1026 [erg/sr]

Neutron Time Profile on Nov 4th 2003 Power index = – 3.9 ± 0.5 Haleakala NM Power index = – 3.9 ± 0.5 Flux at 100MeV = (1.5 ± 0.6) ×1028[/MeV/sr] Mexico NM ・ Attenuation : Shibata program ・ Efficiency of NM : Clem & Dorman ・ Efficiency of SNT : GEANT3 FLUKA-COLOR Hawaii SNT