Participants of the TANGRA Collaboration and Dubna’s Diamant company continue to develop methodological foundations for the application of the tagged neutron method (TNM) for analysing the content of carbon and other elements in the soil. As part of the 2025 field season, joint experiments are planned to be conducted with partners specialising in soil science, agriculture, forestry, ecology, and climate projects. A distinguishing feature of the upcoming expeditions will be the use of a compact unmanned transport platform purchased by JINR for these purposes.

Soil fertility, along with conservation and restoration of soil ecosystems, are the key factors of sustainable global food production. In addition, soils are the largest carbon reservoir in terrestrial ecosystems, and controlling carbon capacity plays an important role in mitigating climate change and adapting to it. A wide variety of tasks in these areas are focused on determining soil elemental composition.

The need to cover larger territories while simultaneously increasing measurement accuracy while monitoring the content of carbon and other elements in the soil creates a demand for the development of a tool set that reduces sample preparation, provides field or mobile versions of instruments or laboratories, automates analysis, and allows determining multiple characteristics in one measurement.

The tagged neutron method can be used for the elemental analysis of any substances. Carbon in particular is one of the most “convenient” elements for TNM analysis, since its gamma spectrum consists of just one 4.44 MeV line, with the energy enough to penetrate through large amounts of analysed soil.

The radio-controlled rover will transport a module containing a neutron generator that creates a 14 MeV fast neutron beam and gamma detectors that register the characteristic radiation of soil’s main elements. An important feature is that the measurements will be made while the rover is moving through the field. The device will allow determining the content of various elements in soil up to 30 cm deep without sample collection and preparation.