Time of Flight neutron Spectrometer for inelastic neutron scattering studies is being commissioned at Dhruva reactor. Neutron pulse tagging is carried out using the Fermi chopper. Scattered neutrons at maximum possible scattered solid angle are needed to be detected along with the time information at detector. Precise and efficient detection system is essential for measurement of spatial and temporal distribution. Detection area is optimized to cover an angle of 70° in horizontal direction and 23° in vertical direction. Position sensitive detectors (PSDs) are designed with judicial use of precious ³He gas and a few PSDs with BF3 gas as suitable alternative for ³He gas. An array of vertically arranged 1 m long, 50 PSDs, covers the arc length of 2.5 m and detection area 2.5 m². The design of the BF3 PSDs is supported by investigations on the gas purity, fill gas pressure, drift region, drift field and neutron absorption in cathode wall. Design details and performance of the PSDs are presented in the paper.