Comparison of Radon and Thoron Concentration Measuring Systems Among Asian Countries.

Comparison is an important role in the quality control and quality assurance for any measuring system. Due to the future legal regulations regarding radon levels in the air, maintaining the system quality and harmonization of results as well as validation of radon and thoron measuring systems is important. The aim of this work is to validate the degrees of equivalence and measurement precisions of the existing five radon and four thoron measuring systems located in four Asian countries (China, India, Japan and Thailand) through comparison experiment.

A WALK-IN TYPE CALIBRATION CHAMBER FACILITY FOR 222Rn MEASURING DEVICES AND INTER-COMPARISON EXERCISES.

A walk-in type 222Rn calibration chamber of volume 22.7 m3, which has traceability to international standards, is established at the Centre for Advanced Research in Environmental Radioactivity, Mangalore University, India. It has a human-machine interface communication system, a programmable logic controller and sensor feedback circuit for controlling and data acquisition of relative humidity (RH) and temperature (T).

THE SCREENING INDOOR RADON AND PRELIMINARY STUDY OF INDOOR THORON CONCENTRATION LEVELS IN KUWAIT.

Indoor measurements of radon and thoron in Kuwait were conducted during the years 2015 and 2016. In this study, 65 dwellings were selected for the long-term radon-thoron survey using passive nuclear track monitors. The monitors (at least one) were used at various locations in the dwellings for 83-306 days.

Outdoor dose rate mapping in Kuwait.

As part of ongoing efforts to develop the data base required for the gamma dose rate baseline in Kuwait, a survey of ambient outdoor gamma-ray dose rates was carried out in 112 locations within the country. Measurements were performed, during the period from August 2013 to March 2016, in various undisturbed open areas in the desert using a NaI dosimeter/spectrometer. The dose rates were recorded along with the corresponding gamma-ray spectra for in-situ relative contribution of the primordial radionuclides and Cs in the outdoor environment.

AREA MONITORING OF AMBIENT DOSE RATES IN PARTS OF SOUTH-WESTERN NIGERIA USING A GPS-INTEGRATED RADIATION SURVEY METER.

A radiation monitoring system comprising a Geiger-Muller counter connected to a smart phone via Bluetooth was used for a dose rate survey in some parts of south-western Nigeria. The smart phone has the Geographical Positioning System, which provides the navigation information and saves it along with the dose rate data. A large number of data points was obtained that shows the dose rate distribution within the region.

Indoor Gamma Dose Rates In Kuwait Using Handheld Gamma-ray Spectrometer.

A survey of indoor gamma dose rates was carried out in Kuwait using a NaI dosimeter/spectrometer. The measurements started from May 2013 until April 2015 and covered different locations within 200 dwellings: 158 halls, 26 rooms, 17 basements, and 43 kitchens (total of 244 locations). Alongside the dose rate measurements, gamma-ray spectra were also acquired to evaluate the relative contributions of K, Bi, and Tl and check the presence of Cs.

Application of the Monte Carlo method for the efficiency calibration of CsI and NaI detectors for gamma-ray measurements from terrestrial samples.

Gamma-ray measurements in terrestrial/environmental samples require the use of high efficient detectors because of the low level of the radionuclide activity concentrations in the samples; thus scintillators are suitable for this purpose. Two scintillation detectors were studied in this work; CsI(Tl) and NaI(Tl) with identical size for measurement of terrestrial samples for performance study. This work describes a Monte Carlo method for making the full-energy efficiency calibration curves for both detectors using gamma-ray energies associated with the decay of naturally occurring radionuclides (137)Cs (661keV), (40)K (1460keV), (238)U ((214)Bi, 1764keV) and (232)Th ((208)Tl, 2614keV), which are found in terrestrial samples.

A study on radon absorption efficiencies of edible oils produced in India.

A study on absorption of radon by different edible oils of plant origins produced and used in India was conducted in order to identify efficient radon-absorbing oils. A comparative study of radon absorption by edible oils of India with that of olive oil, which is known as a good absorber of radon, was also carried out. The study was performed by bubbling known concentrations of radon through the oil contained in a bottle and then evaluating the bubbled oil by gamma-ray spectrometry using an HPGe detector.

Simplified slow anti-coincidence circuit for Compton suppression systems.

Slow coincidence circuits for the anti-coincidence measurements have been considered for use in Compton suppression technique. The simplified version of the slow circuit has been found to be fast enough, satisfactory and allows an easy system setup, particularly with the advantage of the automatic threshold setting of the low-level discrimination. A well-type NaI detector as the main detector surrounded by plastic guard detector has been arranged to investigate the performance of the Compton suppression spectrometer using the simplified slow circuit.

Indoor radon in Kuwait.

Indoor radon measurements were carried out in 300 dwellings in Kuwait using duplicate sets of charcoal detectors. Measurements were made at three different locations in the dwellings: living rooms, bedrooms, and basements. The results show that the radon concentration in the dwellings of Kuwait was found to vary in the range of 4.

Towards the use of small amounts of activated charcoal along with well-type NaI(Tl) detector for indoor radon measurements.

The feasibility of using small quantities of activated charcoal and a 7.6 cm x 7.6 cm NaI(Tl) well-type detector was investigated for indoor radon measurements.

A simple bubbling system for measuring radon (222Rn) gas concentrations in water samples based on the high solubility of radon in olive oil.

Based on the different levels of solubility of radon gas in organic solvents and water, a bubbling system has been developed to transfer radon gas, dissolving naturally in water samples, to an organic solvent, i.e. olive oil, which is known to be a good solvent of radon gas.

Measurements of 210Pb concentrations in airborne in Kuwait.

The concentrations of 210Pb in the atmosphere of Kuwait City have been monitored over a period of five years (January 1994 to December 1998) using cellulose air filters for analysis with liquid scintillation counting forgross beta. Results show that the distribution of daily averaged 210Pb concentrations varied from 0.002 to 2.

Radioactivity concentrations in sediments and their correlation to the coastal structure in Kuwait.

Gamma-ray spectrometric measurements were performed on sediment samples from the coast of Kuwait to study the concentration of natural as well as man-made radioactive sources. The coast of Kuwait, which extends for some 170 km is mainly soft sedimentary colitic limestones or sandstones, overlaid in many areas with beach or wind-blown sand. In the north, suspended material from the Shatt Al-Arab delta has settled to form extensive soft areas of intertidal mud within Kuwait Bay.

Allele frequencies and molecular genotyping of the ABO blood group system in a Kuwaiti population.

The phenotypic distributions of observed numbers of ABO blood groups in a Kuwaiti sample population of 18,558 subjects are 4962 (26.7%) with A, 4,462 (24.1%) with B, 858 (4.

Variations in 7Be concentrations in the atmosphere of Kuwait during the period 1994 to 1998.

The Beryllium-7 (7Be) concentrations in the atmosphere of Kuwait, as found by gamma-ray measurements for 243 air filters collected over a five-year period, produced variable values ranging from 0.2 to 14.9 mBq/m3 with a behavior pattern which has oscillatory characteristics, with increased activities occurring in the summer months of each year.

Comparative study of desert truffles from Kuwait and other countries in the Middle East for radionuclide concentration.

Concentrations of some radionuclides, including 137Cs, in desert truffles in Kuwait were studied and compared with similar samples from other countries in the Middle East, namely Iran, Egypt, and Tunisia. In addition, sand samples from Kuwait were assayed to calculate the transfer factor of the radionuclides under consideration. The measured concentrations of 40K, 226Ra, and 137Cs show that 137Cs is much higher in Egyptian samples, whereas 40K is much lower in samples from Tunisia.