VARIATION OF GAMMA-RAY AND PARTICLE FLUXES AT THE SEA-LEVEL DURING THE TOTAL SOLAR ECLIPSE OF 24 OCTOBER, 1995

A Total Solar Eclipse (TSE) was observed from Diamond Harbour (lat. 22 .2 degrees N, long 88.2 degrees E) on 24 October 1995. The variation o f gamma-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 (similar to 25%) in the intensity of gamma-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 less than or equal to 10% whic h was not significant statistically. Low energy gamma-ray fluxes at se a level originate from the secondary electron-photon components of cos mic rays in the atmosphere; its modulation by TSE is interpreted as fo llows. 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 mu(+/-) mesons (from the decay of the pi(+/-) mesons) decay to e(+/-). This leads to a small reductio n in the flux of electron-photon component at sea level which originat es from this branch; the main branch of e - gamma component from pi(0) 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 s ea level is expected. These are consistent with the present observatio ns. For a better understanding, further studies of this new phenomenon during future TSE are suggested.