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Experimental study of Variation of Secondary Cosmic Gamma Ray Flux and Energy during Partial Solar Eclipse of 4th January 2011 at Udaipur, India

Author Affiliations

  • 1Department of Physics, B.N.P.G. College, M.L. Sukhadia University, Udaipur, INDIA
  • 2 Department of Physics, M.L. Sukhadia University, Udaipur, INDIA

Res. J. Physical Sci., Volume 1, Issue (5), Pages 22-30, June,4 (2013)


The partial solar eclipse at Udaipur (24° 34’ 16.14”N, 73° 41’ 30.22”E), India was experimentally observed on th January 2011. A cadence of data was collected using ground based NaI (Tl) Scintillation detector. The analyzed data reveal significant variation in secondary cosmic gamma ray (SCGR) flux and energy. The measured maximum drop in SCGR flux during the partial solar eclipse was about 15 %. This was found well in agreement with what the earlier studies reported during solar eclipse. But unlike earlier findings, we observed an additional peak in the energy spectrum of SCGR flux in the energy range extending from 650.73 keV to 666.51 keV and variation of amplitude in the range of 21% -30% during the progress of solar eclipse. These results of variation of SCGR flux can be explained on the basis of well established shadowing effect of the moon. During maximum eclipse, the galactic cosmic radiations (GCR) and solar energetic particles (SEP) reaching towards the earth atmosphere are obstructed by the moon. However the variation of energy and amplitude of an additional peak observed in SCGR spectrum can be attributed to the gamma ray emission from the moon’s surface near its limb by hard hitting of SEP and bent GCR under the influence of strong magnetic field of the sun and the interplanetary magnetic field.


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