Active-sterile neutrino mixing constraints using reactor antineutrinos with the ISMRAN setup

In this work, we present an analysis of the sensitivity to the active-sterile neutrino mixing with the Indian Scintillator Matrix for Reactor Anti-Neutrino (ISMRAN) experimental setup at very short baseline. The 3 (active) + 1 (sterile) neutrino oscillation model is considered to study the sensitivity of the active-sterile neutrino in the mass splitting and mixing angle plane. In this article, we have considered the measurement of electron antineutrino induced events employing a single detector which can be placed either at a single position or moved between a near and far positions from the given reactor core. Results extracted in the later case are independent of the theoretical prediction of the reactor anti-neutrino spectrum and detector related systematic uncertainties. Our analysis shows that the results obtained from the measurement carried out at combination of the near and far detector positions are improved significantly at higher Amt compared to the ones obtained with the measurement at a single detector position only. It is found that the best possible combination of near and far detector positions from a 100 MWth, power DHRUVA research reactor core are 7 m and 9 m, respectively, for which ISMRAN setup can exclude in the range 1.4 eV(2) <= Delta m(41)(2) < 4.0 eV(2) of reactor antineutrino anomaly region along with the present best-fit point of activesterile neutrino oscillation parameters. At those combinations of detector positions, the ISMRAN setup can observe the active sterile neutrino oscillation with a 95% confidence level provided that sin(2) 2 theta(14 )>= 0.09 at Delta m(41)(2) = 1 eV(2) for an exposure of 1 ton-yr. The active-sterile neutrino mixing sensitivity can be improved by about 22% at the same exposure by placing the detector at near and far distances of 15 m and 17 m, respectively, from the compact proto-type fast breeder reactor (PFBR) facility which has a higher thermal power of 1250 MWth.