In case of nuclear accident or an act of terrorism, such as planting a dirty bomb, the nuclear and radioactive materials could be spread over a large area. The environmental radioactivity information has to be obtained rather fast in order to secure the safety of any activity in these potentially high-level radiation contaminated areas. In addition, a lack of both social infrastructure and environmental radiation information may be expected in this area. Therefore, the sampling process must be carried out in a timely and efficient manner. In this study, a probe operated via a distribution method was developed to improve the efficiency of the sampling process by identifying the location and nuclides of leaked materials. For distribution type operation, CsI(Tl) and SiPM were applied to the sensor part of the probe to operate at low voltage operation and for durability. In addition, the power consumption of the data acquisition module and the weight of the probe were optimized for distribution through drones, battery operation, and wireless communication. The energy resolution of this probe was 10.84% at 662 keV and it showed adequate characteristics in the spectrum of nuclear materials. In addition, the practical operability of this probe was verified through determination of the minimum detectable dose rate condition and the difference in the measured values based on the landing orientation.