Simulation study of electron reconstruction with thin iron plates in ICAL

Abstract

The proposed magnetized Iron Calorimeter (ICAL) detector to study atmospheric neutrinos and anti–neutrinos at the India based Neutrino Observatory (INO) is a 50 K ton detector which will have a magnetic field of 1.3 T. The default geometry of ICAL has 56 mm thick iron plates as the interaction material (target), separated by 40 mm gaps in which the active detectors the resistive plate chambers (RPCs) will be placed. This makes ICAL sensitive to muons with energy in the range ∼1-20 GeV, produced in charged current (CC) interactions of atmospheric $\nu_{\mu}$ and $\bar{\nu_{\mu}}$ with iron. It was shown that sub–GeV $\nu_{e}$ and $\bar{\nu_{e}}$ charged current events are sensitive to the leptonic CP phase $\delta_{CP}$ irrespective of the neutrino mass hierarchy. In our new study we explore the possibility of detecting sub– GeV $\nu_{e}$ and $\bar{\nu_{e}}$ in ICAL for different combinations of iron plate thickness, air gaps and different types of active detectors. Energy resolutions for electrons with energy < 1 GeV were obtained for cases with RPC and scintillator as active detectors with 18 mm thick iron and 40 mm thick air gap and compared with each other and also the resolutions for DUNE experiment. In this case, number of hits per layer can be used to reject pion background from electron events. Further studies with 18 mm thick iron plate and a decreased air gap of 12 mm (10 mm scintillator and 2 mm air gap) to improve the energy resolutions for low energy electrons and identification of more variables for background rejection are being performed.