Aim of this research is a hazards assessment of radon concentration and effective radium content were estimated in 24 vegetables and 9 fruits samples that were collected randomly from local markets in Muang Nakhon Phanom Municipality, Thailand by active detecting method (RAD 7). The results showed that radon concentrations in vegetables were in the range of 6.27 – 45.11 Bq/m3, the mean was 21.32±2.36 Bq/m3 and radon concentrations in fruits were in the range of 12.11 – 53.19 Bq/m3, the mean was 27.47±2.81 Bq/m3, respectively. All values of radon concentrations for vegetable and fruits in these study were found to be well below than the international standard level of radon concentration 190 Bq/m3 recommended by the EPA. These results were also used to calculate the average effective dose equivalent (EDE) of radium from vegetables and fruits, calculation was 0.034 µSv/y, this is lower than the effective dose equivalent for the standard value of 1.3 mSv/y recommended by the EPA. This study show that vegetables and fruits were found to be safe from radon contamination.
A low-energy single ion irradiation system is developed in its initiation in Thailand to follow one of the trends in novel ion beam technology exploitation. Single ion irradiation of materials is a highly technological development of ion beam technology. The developed single ion irradiation systems worldwide are primarily in the MeV-energy range and for single cell studies, and recently the trend has been extended to the low-energy range (< 100 keV) but focused on microelectronic applications. Based on our previous research on low-energy ion beam irradiation of biological cells and DNA, we design and simulate a low-energy single ion implantation system, aiming at eventual construction of such a novel ion beam apparatus for applications to the biological studies. In the system, the ion energy is decreased to orders < 1 keV by the existing deceleration lens, then the low-energy ion beam passes through µm slits, and finally, low-energy single ions are obtained by beam scanning with appropriate frequencies from scanner plates and detected by a single ion detection device. Conceptual design, calculation and simulation of this single ion system are presented.
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