The prominent feature of Silicon nanotube metal oxide semiconductor field effect transistor for using radiation-sensitive metal-oxide-silicon field-effect transistor (RADFET) application is its high Ion/Ioff ratio, minimal leakage current and less sensitive to short channel effects. Due to the above features the radiation behaviour of the device is studied to check for the applicability of a RADFET. Here both uniform and non-uniform irradiation characteristics are analysed. The focus of this study is on electrical characteristics and sensitivity, which is measured as variation threshold voltage of radiated and unirradiated device. It was found that on irradiation the surface potential variation is high for 40 nm channel length hence the analysis is conducted for the same. It was proven to be successful, as the device achieves high Ion/Ioff ratio of the order 1013 and a sensitivity of 2.26 mv/Gy. The obtained results are compared with DG RADFET and JL DG RADFET and it shows that Core gate Silicon nanotube RADFET has better electrical characteristics and sensitivity. The simulations are performed in Silvaco 3-D Atlas TCAD simulation software.