The ICAL prototype detector at the Variable Energy Cyclotron Centre (VECC), Kolkata, has 13 layers of Iron plates interleaved by RPCs in the gap between these layers. The dimension of the Iron plates is 2.48m (length) x 2.17m (width) x 0.05m (thick). The total height of the detector stack is 1.302m. Out of the 12 RPCs, 8 are made of Glass and the rest are of Bakelite. A total of 4 coils, each having 5 turns, wound perpendicular to the plane of the Iron plates make-up an electromagnet which weighs about 50 tons (~0.1% of the main ICAL) and which can be magnetized up to 1.6 Tesla. It is this feature of the magnetic field that makes it different from the prototypes at TIFR. The 50kton ICAL magnet would be the world’s biggest electromagnet and the prototype at VECC is a stepping stone to it.
This prototype detector is built for the following purposes:
To study the working behavior of RPCs together with the front end electronics in presence of magnetic field.
To study the feasibility of using Bakelite RPCs for the ICAL experiment in view of its bigger signal amplitude which eliminates the requirement of dedicated electronics for amplification, which is necessary for Glass RPCs.
To study and understand the characteristics of the magnetic field (hysteresis curve, field uniformity and confinement, for example) to obtain a field map that can be used for physics simulations.
To understand the technical challenges that one might face later in constructing the 50kton electromagnet for ICAL.
To conduct various studies using cosmic-muons with which simulation algorithms like the Kalman Filter for momentum reconstruction for INO-ICAL can be validated and tested.
The main on-going activity is the analysis of cosmic muon data acquired using different current configurations for the magnet. A study of the curvature of the cosmic muon tracks from reconstructed momentum using the INO-ICAL Kalman Filter is being undertaken by the simulations team.