Cosmic Muon Momentum Spectra at Madurai

Abstract

A magnetised mini Iron Calormeter (mini-ICAL) with 10 layers of 2 m $\times$ 2 m RPCs interspersed with 11 layers of 5.6cm thick soft-iron has been built to study the performance of INO electronics in magnetic field as well as to achieve confidence on other engineering aspects of the ICAL detector and magnet. This detector is operational at IICHEP, Madurai, and is collecting data, triggered by muons produced in the cosmic ray showers at the top of the atmosphere due to the interactions of high energetic cosmic rays with the atmosphere. A magnetic field of $\sim$1.4 T is obtained in the iron by applying 900A of current through the copper coils. The trajectories of the charged particles are fitted to extract the momentum of the muons traversed through the detector. This paper will compare the measured momentum spectra with the Monte-Carlo prediction and the reconstructed spectra is unfolded to eliminate the detector’s effects in order to obtain the true momentum spectra of cosmic muons at Madurai.