Measurements of thorium content and radioactivity gas mantles

الملخص EN

Natural gamma rays from the thorium (232Th) isotope and its daughters ١١؛ variou؛ imported gas lantern mantles were measured at the KFUPM gamma-ray speetroscop; setup.

The origin of the natural gamma rays was qualitatively determined by a wel shielded Hyper Pure Germanium (HPGe) detector, and then the concentration of th< radioactive element was quantitatively measured using a 5"x5" Nal(Tl) detector an، a PC-based data acquisition and analysis system.

The mantle samples, of a few gram; each, were studied for thorium concentration and its gamma ray radioactivity.

In orde to determine the absolute concentrations, the sample activity was compared with th( activities of standards.

The concentration of Th was determined in weight percen (wt.%) and ranged from 3.6 to 9.2% while the activity per mantle ranged from ? t< 25 nCi.

Thorium distribution measurement in the mantle was carried out using CR-3' nuclear track detectors.

The external gamma rays dose equivalent rate from one man til sample was measured as 4 fiSv/h when the mantle was placed on the detector surface The calculated committed dose equivalent for ingestion of 10% of each of the lowes and the highest concentration ofthorium mantles was found to be 0.5 mSv and 1.8 mS’ respectively.-