Speaker
Description
Extensive air shower (EAS) arrays with muon identification capability are ideal
to investigate diffuse $\gamma$-rays at multi-TeV energies. The GRAPES-3
experiment at Ooty in India is equipped with a dense array of 400 scintillator
detectors and a large area (560 m$^2$) tracking compact muon detector. It is
designed to investigate $\gamma$-rays and cosmic ray nuclear composition in the
energy range of 10$^{13}$ - 10$^{16}$ eV. The muon content in EAS is an
effective parameter to discriminate the tiny flux of $\gamma$-rays from the
overwhelming background of charged cosmic rays. The GRAPES-3 group is
constructing another 560~m$^2$ area muon detector close to the existing one.
With the area getting doubled, a significant enhancement in the rejection of
cosmic ray background is expected to be achieved. We carried out a detailed Monte Carlo
simulation to compute the cosmic ray rejection efficiency and estimated
the GRAPES-3 sensitivity for diffuse $\gamma$-ray detection. In this meeting,
the results from the simulation study will be presented and the construction
status of the muon detector will be updated.
