[en] Since many years our laboratories work in collaboration with the Institut for the Nuclear Research and Nuclear Energy of the Bulgarian Sciences Academy at Sofia in order to develop, optimise and use the thermoluminescent CaSO₄:Dy detectors for personal dosimetry. After this positive experience we have extended our research to work about the development of these detectors for natural radiation measurements in soil. Indeed, the determination of the natural radioactivity in soil suppose that, we could have many probes without maintenance placed in different sites during many days or many weeks. What's more, the detectors will have to support a great variations of temperature and of atmospheric environment (dry or wet ) without discrepancies in the results. In this aim, we have studied the realisation of a thermoluminescent probe for alpha and gamma measurements the most cheap and easily feasible. A previous study was done by numerical simulation. The behaviour of thermoluminescent detectors in gamma environment is calculated with the Monte-Carlo EGS4 code and its behaviour in alpha environment with an other Monte-Carlo TLALFA code elaborated in LMIT laboratory. The results obtained are allowed to build two versions of probe which take into account the ground's humidity. The first belongs an air pumping system to do alpha and gamma measurements. The second without pump is fabricated and it will used to determine only the gamma contribution. Then measurements in mixed environment were done in laboratory in order to validate the both device. The whole of results are presented here and discussed. They permit to plan the type of detectors application for measurements in soil. (author)