Global Satellite Session: State of Physics Research in Cameroon

After presenting some facts on research in nuclear physics in Cameroon, we will concentrate on the results of radon and thoron mapping, geogenic radon, radon action plan and radon regulation in Cameroon with emphasis on thoron exposure. 

Radon measurements indoors started in 2012 in Cameroon Various techniques were used: Electret ionization chambers, radon-thoron discriminative detectors (RADUET), thoron progeny monitors (TnP), radon track detectors (RADTRAK), direct radon progeny sensors (DRPS) and direct thoron progeny sensors (DTPS). Up to date, radon was measured in about 3500 houses. A total of 1500 RADTRAK, 1500 RADUET and 1400 TnP monitors were deployed at the national scale. Geogenic radon was measured since 2021 in about 1500 points.  In the bauxite bearing area of Fongo-Tongo in West region and the radon prone area of Ngaoundere city in the Adamawa region in Cameroon thoron concentration ranges between 36- 1000 Bq m-3 and 17-1000 Bq m-3 with the average values of 300 Bq m-3 and 207 Bq m-3, respectively. 48% and 28% of houses have thoron concentration above 300 Bq m-3 for these two areas, respectively. Globally 14% of houses have thoron concentration above 300 Bq m-3, 8% above 400 Bq m-3, and 4% above 500 Bq m-3 in the whole country. The choice of 500 Bq m-3 as the reference value for thoron is realistic taking account of the socio-economic conditions of the country. The corresponding inhalation dose is about 10 mSv.yr-1, equivalent to that of radon for 300 Bq m-3.

In 2020 the national radon action plan was established in Cameroon. Currently the regulation on radon exposure is being finalized. Thoron will be considered in radon regulation.