Farrash (2020) The effects of CT x-ray tube voltage and current variations on the relative electron density (RED) and CT number conversion curves,

Solid state nuclear track detectors are used in very broad fields of technical applications and successfully applied in different areas of environmental physics and geophysics. Radon concentration and surface exhalation rate for phosphate samples from El-Sebaeya and Abu-Tartur, Egypt, were measured using nuclear tracks detectors from types CR-39 and LR-115. The average values of radon concentration are 12711.03 and 10925.02 Bqm À3 in El-Sebaeya area using CR-39 and LR-115 detectors, respectively. Also the average values of radon concentration are 15824.16 and13601.48 Bqm À3 in Abu-Tartur area using CR-39 and LR-115 detectors, respectively. From the obtained results we can conclude that the average values of radon concentration in Abu-Tartur are higher than El-Sebaeya. The present study is important to detect any harmful radiation which, can be used as reference information to assess any changes in the radioactive background level in the surrounding environment.

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In this paper, forty samples of building materials collected from local market in Dakahlia Governorate, Egypt. The radon concentration in these samples were measured using solid state nuclear track detector. Solid state nuclear track detectors have become an important tool in every investigation of the radon levels in the surrounding environment. The obtained results have shown that the highest average of radon concentration in granite samples and the average value is 845.43 Bqm −3 , while the lowest average value is white cement 68.42 Bqm −3 . The present work is important to detect any harmful radiation in our houses that affect human and to establish a data base for building materials which, used in a local market. The obtained results show that the radon concentrations of the most samples are below the allowed limit of ICRP.

The environmental radioactivity of the Lake Manzala, Egypt, has been investigated to determine the level of the natural radioactivity and the radiological impact for the targeted area. Twenty sediment samples were collected from pre-determined locations, which involve deep springs and lakes, particularly samples taken from places receiving sewage pollutants, fertilizers and disinfection materials used in the agricultural area and fish farms. The gamma-emitting nuclides library has been designed to assess the activity concentration for radionuclides belonging to the natural series of uranium and thorium ( 208 Tl, 212 Bi, 212 Pb, 214 Bi, 214 Pb, 226 Ra, 228 Ac, 234 Th, 235 U), and 40 K gamma-line. The measured overall average value of the radionuclides' activity concentration was 15 Bq/kg, while for 40 K was 286 Bq/kg. The true coincidence summing was corrected using the Genie-2000 software, and LabSOCS was used to calculate the total efficiencies. Most of the resulted values are moderated, indicating normal levels compared to the international and worldwide reference values in this regard.