Simulation studies for false positive event rate due to muon-induced neutral particles for a shallow depth ICAL detector

The India-based Neutrino Observatory (INO) is proposed to house Iron Calorimeter (ICAL) detector and will be located at Bodi West Hills in the southern part of India. At the chosen location the detector will be covered from all the sides by about 1km of rock. The rock overburden reduces the cosmic muon flux by a factor of 10⁶. The same level of cosmic muon background reduction can be achieved by a combination of a Shallow depth (of about 100m depth) ICAL (SICAL) and Cosmic Muon Veto Detector with veto efficiency 99.99%. The feasibility study of CMVD has already been done as discussed. In the case of SICAL, the investigation of muon-induced neutral background becomes crucial as these neutrals can mimic neutrino events. In this paper, a GEANT4 based study is done to estimate the rate of such false positive signals in SICAL