Variation of γ-Ray and Particle Fluxes At the Sea Level During the Total Solar Eclipse of 24 October, 1995

Abstract

A Total Solar Eclipse (TSE) was observed from Diamond Harbour (lat. 22.2°N, long 88.2°E) on 24 October 1995. The variation of γ-ray intensity was measured in the energy range of 0.3–3.0 MeV for different time spans throughout the period of the eclipse. A CR-39 detector was used to look at the change in the fluxes of neutral and charged particles. The maximum drop (∼ 25%) in the intensity of γ-ray was observed in the range 2.5–3 MeV during TSE. The CR-39 results showed the appearance of a good number of tracks and a small variation of proton and neutron flux of ≤ 10% which was not significant statistically. Low energy γ-ray fluxes at sea level originate from the secondary electron-photon components of cosmic rays in the atmosphere; its modulation by TSE is interpreted as follows. The cooling of the atmosphere in the path of the umbra induces a reduction of the height of the main production layer of the nuclear component, as a result of which, fewer µ± mesons (from the decay of theπ± mesons) decay to e±. This leads to a small reduction in the flux of electron-photon component at sea level which originates from this branch; the main branch of e - γ component from π0 decay remains nearly unaffected. As the total mass of air remains the same, little or no change in the slow proton or the neutron flux at sea level is expected. These are consistent with the present observations. For a better understanding, further studies of this new phenomenon during future TSE are suggested.