Drone measures radioactivity in the soil
https://www.futurefarming.com/tech-in-focus/drones/drone-measures-radioactivity-in-the-soil/
airtime and detector weight burns up batteries, so drone use hasn't been effective for surveying. The abstract doesn't answer how these issues are resolved, so you have to download a 7+MB document from a german website... I'll pass.
If the PhD student has magically solved the weight problem, that should be the key to the abstract.
From the picture, I'm guessing his detector is small and useless for most radiological soil sampling needs.