Natural Radioactivity in Red Clay Brick Manufactured in Tlemcen-Algeria, Using Well-Shape NaI(Tl) Detector

Abstract

The presence of natural radioactivity in brick and other building materials results in internal and external exposure to the general public. Therefore, it is desirable to determine the concentration of naturally occurring radionuclides. Bricks are one of the main components in building construction beside cements, granites and sand. Thus, this research has been carried out in order to investigate the levels of natural radioactivity and associated radiation hazard in Algerian red brick. The natural radioactivity due to the presence of ²²⁶Ra, ²³²Th and ⁴⁰K in brick samples used as building materials in Tlemcen province - Algeria was measured by gamma spectrometry using NaI(Tl) scintillation well-shaped detector. In this context, brick samples were collected from two manufactories Tafna and Tounan. The mean values of activity concentrations for ²²⁶Ra, ²³²Th and ⁴⁰K were found to be in the main value of 15.5Bq.kg^-1, 11Bq.kg^-1, and 196.5Bq.kg^-1, respectively. The concentrations of these natural radionuclides were compared with the reported data for other countries and were found significantly lower than the world wide average (1,2). Radium equivalent activities were calculated (41.3 to 51.4) Bq.kg^–1 for the analyzed samples to assess the radiation hazards arising due to the presence of these radionuclides in the samples. The calculated radium equivalent activities are lower than the limit set by the OECD report 370 Bq.kg^–1 (3). The measured representative level index values for the investigated samples varied in the range (0.31 to 0.38) Bq.kg¹.  External and internal hazard index (H_ex,H_in), the specific dose rates in door (D) and the annual effective dose (DE) due to gamma radiation from building materials was calculated.

Keywords: Brick, natural radioactivity, gamma radiation, absorbed dose, radiation exposure, Potassium, Thorium, Uranium; NaI(Tl) detector, Tlemcen.