Simulation work carried out for INO can be divided into following four steps:

1. Simulation work carried out for INO can be divided into following four steps: Generator of Atmospheric neutrinos. Simulation of Detector. Track Reconstruction. Data Analysis. Generator of Atmospheric Neutrinos: The first step in simulation will be to generate atmospheric neutrinos interaction in our detector. Neutrinos produced in the atmosphere travel through the atmosphere and earth before reaching the detector. Depending on the distance they travel they undergo oscillation on their way. Neutrinos undergo different type of interaction with matter. Depending on the cross section of this interactions, only a small fraction of neutrinos will interact with matter in the detector and produce secondary particle namely leptons and hadrons. Using the flux of atmospheric neutrinos, the flux of neutrinos at the detector over a period of time is calculated and randomly different types of interaction are simulated. GENERATOR uses available simulation package to carry out the process described above and gives energy and momentum of neutrinos that underwent interaction and of the secondary particles produced. DETECTOR SIMULATION: Next step in simulation is to see how these secondary particles produced in neutrino interaction propagate through the Detector and give us signal. As these particle pass through the detector they ionize the gas in RPC the active detector. This signals are picked up by the supporting electronics to give us position, time and charge deposited. Different interaction leave different signature in the detector. Using simulation package called GEANT 4 ( GEANT stand for Geometry and Tracking.) first a detector is made, then the particles produces by the GENERATOR are passes to this DETECTOR SIMULATION , GEANT4 propagates these particles through the detector and simulate the interaction it will undergo on its way before losing all its energy. And then the point at which the particles passed through the active detector is recorded as will be done with real detector. Thus as the output of detector simulation we have signals ( lets call is a Hit) in different layer of RPC through which the particle had passed through ionizing the gas, its position, time and the charge deposited in RPC. Eventually giving use tracks of particles in the detector. For this reason ICAL is also a TRACKING DETECTOR. RECONSTRUCTION: All three energy of the neutrino that interacts with the detector is shared by the secondary particle produced. If we can reconstruct back the energy of these secondary particle i.e. lepton and hadrons we can sum it up to get back the energy of the neutrinos. For atmospheric neutrinos oscillation studies we will be looking at muon neutrinos, and suppression in number of mouns from the expected no. So in most of the interaction we intend to get a muon which takes away large fraction of neutrino energy. Muons leave long track while hadron leaves shower of hits near the vertex of interaction. Thus in this step we will use the output from the Detector Simulation to fit a data to get back muon and hadron energy and direction which in turn will tell us about neutrino energy and direction. This is called RECONSTRUCTION OF NEUTRINO PARAMETERS. RECONSTRUCTION is done in two steops: 1) Separate the HITS ( point where the particle ionized the gas in the gas detector.) that more likely feature a track from the hadron hits and noise hits (signals from some stray interaction of electronic noise.) 2) Use KALMAN FILTER TECHNIQUE to get back the reconstruction of momentum, direction, and charge of the moun. 3) Pick up the hit near the vertex which are more likely to come from hadron shower and use appropriate calibration to get back the energy of hadrons. Different technique in used for neutral current. PHYSICS ANALYSIS: After having reconstructed back parameters of neutrino, this data is analyzed. This will help us understand the physics reach of INO detector we will be building. Simulation studies also help us to optimize the parameters of the detector in order to get maximum out of the result we intent to do. Show a plot of neutrino oscillation form simulated data. I have made the second half of the poster, first half which is made by tarak will have neutrino information. A patch between the two, telling why we do simulation studies will be added. And a box in the INO-ICAL detector. The first part will have diagram showing steps of simulation. Will you please go through this and tell me if the contents are OK. Or some thing more to added to this.