arXiv subjects

G. Christodoulides

Publications and source records attributed to G. Christodoulides.

3 recordsLinked to original sources

arXiv2003

Gamma radiation measurements and dose rates in commercially-used natural tiling rocks (granites)

The gamma radiation in samples of a variety of natural tiling rocks (granites) imported in Cyprus for use in the building industry was measured, employing high-resolution gamma-ray spectroscopy. The rock samples were pulverized, sealed in 1 litre plastic Marinelli beakers, and measured in the laboratory with an accumulating time between 10 and 14 hours each. From the measured gamma-ray spectra, activity concentrations were determined for Th-232 (range from 1 to 906 Bq/kg), U-238 (from 1 to 588 Bq/kg) and K-40 (from 50 to 1606 Bq/kg). The total absorbed dose rates in air calculated from the concentrations of the three radionuclides, Th-232 and U-238 series and K-40, ranged from 7 to 1209 nGy/h for full utilization of the materials, from 4 to 605 nGy/h for half utilization and from 2 to 302 nGy/h for one quarter utilization. The total effective dose rates per person indoors were determined to be between 0.02 to 2.97 mSv/y for half utilization of the materials. Applying dose criteria recently recommended by the EU for superficial materials, 25 of the samples meet the exemption dose limit of 0.3 mSv/y, two of them meet the upper dose limit of 1 mSv/y and only one exceeds clearly this limit.

physics.med-ph↗

arXiv2003

Indoor radon (Rn-222) concentration measurements in Cyprus using high-sensitivity portable detectors

Using high--sensitivity radon (Rn-222) portable detectors (passive electronic devices of the type RADIM3), the airborne Rn-222 concentration in the interior of various Cypriot buildings and dwellings was measured. For each preselected building and dwelling, a calibrated detector was put into a closed room, and the Rn-222 concentration was registered in sampling intervals of 2 to 4 hours for a total counting time of typically 48 hours. Rn-222 activity concentrations were found to be in the range of 6.2 to 102.8 Bq/m**3, with an overall arithmetic mean value of (19.3 +- 14.7) Bq/m**3. This value is by a factor of two below the world average (population-weighted) value of 39 Bq/m**3. The total annual effective dose equivalent to the Cypriot population was calculated to be between 0.16 and 2.6 mSv with an overall arithmetic mean value of (0.49 +- 0.37) mSv.

physics.med-ph↗

arXiv2002

Gamma-ray measurements of naturally occurring radioactive samples from Cyprus characteristic geological rocks

Using high-resolution gamma-ray spectroscopy, the terrestrial gamma radiation in all the predominant types of geological rock formations appearing in Cyprus was measured. Soil samples were collected from each rock type, sealed in 1-litre plastic Marinelli beakers, and measured in the laboratory for 24 hours each. From the measured gamma-ray spectra, activity concentrations were determined for Th-232 (range from 1.3 to 52.8 Bq/kg), U-238 (from 0.9 to 90.3 Bq/kg) and K-40 (from 13 to 894 Bq/kg). Elemental concentrations mean values of (2.8 +- 0.7) ppm, (1.3 +- 0.3) ppm and (0.6 +- 0.1) % were extracted, for thorium, uranium and potassium, respectively. Absorbed dose rates in air outdoors were calculated to be in the range of 0.1-50 nGy/h, depending on the geological features, with an overall mean value of (14.7 +- 7.3) nGy/h. The corresponding effective dose rates per person outdoors were estimated to be between 0.1 and 61.4 microSv/y, assuming a 20% occupancy factor.

physics.med-ph↗