A 10 y (1999-2008) birth records from two public and most accessible maternity hospitals locally in the city of Abeokuta, Nigeria were used to investigate the possible association of high outdoor gamma radiation expos...A 10 y (1999-2008) birth records from two public and most accessible maternity hospitals locally in the city of Abeokuta, Nigeria were used to investigate the possible association of high outdoor gamma radiation exposure on reproductive abnormalities in the city. From the delivery record of 11,923 births in the period under study, a total number of 485 incidences of reproductive abnormalities were recoded. These incidences comprise 228 multiple births, 190 still births and, 67 premature births. Using the available terrestrial gamma radiation exposure data for the city and different reproductive abnormalities, regression assessment was carried out using the Pearson Product Moment (PPM) correlation statistics. The correlation showed that the incidences of reproductive abnormalities and the radiation dose levels were negatively correlated and correlation coefficient values were very low for each of the reproductive abnormalities considered. Factors such as socio-economic potentials of patients, dietary and other environmental factors may have substantial influence on the reproductive defects in the area other than radiation. However, the present study has added to the radiometric information needed in understanding the relationship between natural outdoor radiation exposure and occurrences of reproductive abnormalities in areas of high radiation in the country.展开更多
The accelerator-generating 6.13 MeV pulsed Gamma by 19F（p, αγ）160 reaction usually synchronizes with an intense bremsstrahlung x-ray which has a maximum energy of 1 MeV. This paper proposes a new method, named the...The accelerator-generating 6.13 MeV pulsed Gamma by 19F（p, αγ）160 reaction usually synchronizes with an intense bremsstrahlung x-ray which has a maximum energy of 1 MeV. This paper proposes a new method, named the scattering and absorbing method, to diagnose the 6.13 MeV Gamma. This method includes two parts： the detector and a scatterer placed in front of the detector. The detector converts the Gamma to electrons and then collects the electrons by a scintillator. In order to restrain the interference of the low-energy background, the scintillator collects the electrons at a small angle. The scintillator is wrapped with electro-absorbing material to absorb the low-energy electrons generated by background x-rays. The theoretical sensitivity ratio of 6.13 MeV Gamma to 1 MeV x-rays is greater than 150. The scatterer is a pretreatment tool to scatter some background x-rays away from the radial beam before they enter the detector. By varying the length, the scatterer can reduce the background x-rays to an acceptable level for the detector.展开更多
The paper first discusses shortcomings of classical adjacent-frame difference. Sec ondly, based on the image energy and high order statistic(HOS) theory, background reconstruction constraints are setup. Under the help...The paper first discusses shortcomings of classical adjacent-frame difference. Sec ondly, based on the image energy and high order statistic(HOS) theory, background reconstruction constraints are setup. Under the help of block-processing technology, background is reconstructed quickly. Finally, background difference is used to detect motion regions instead of adjacent frame difference. The DSP based platform tests indicate the background can be recovered losslessly in about one second, and moving regions are not influenced by moving target speeds. The algorithm has important usage both in theory and applications.展开更多
Water samples from streams, hand-dug wells and boreholes in high background radiation areas in Abeokuta, Nigeria have been collected in order to determine the activity concentrations of 40K, 226Ra and 232Th in the sam...Water samples from streams, hand-dug wells and boreholes in high background radiation areas in Abeokuta, Nigeria have been collected in order to determine the activity concentrations of 40K, 226Ra and 232Th in the samples as well as their physicochemical characteristics. These parameters were evaluated in order to deter-mine the quality of these water sources to the local population, who use these water resources for drinking and domestic activities. Measurements of radioactivity in the water samples were carried out using γ-ray spectroscopy, while standard chemistry methods were used for the physicochemical determinations of these quality parameters. A total of fourteen representative water samples from streams (7), boreholes (4), and hand dug wells (3) were collected for study. The determined activity concentrations of the radionuclides in these samples were used to calculate the effective dose to the population from due to ingestion of and drink-ing the locally available water. The total annual ingestion effective doses were found to vary between 115.00 ±1.15μSv and 1362.30 ±438.02 μSv. The physicochemical parameters where found to be lower than the prescribed standard safe limits in the water sources except for the nitrate and phosphate levels which were particularly high in the water samples from boreholes and hand-dug wells. The radiation effective ingestion dose due to ingestion of water from dug wells and streams was found to be higher than the dose due to inges-tion of water from borehole sources in the studied areas. The results obtained in this study, have been taken as a baselines for physicochemical parameters and activity concentrations of natural radionuclides in water samples within Odeda and Obafemi-owode parts of Abeokuta, Nigeria.展开更多
文摘A 10 y (1999-2008) birth records from two public and most accessible maternity hospitals locally in the city of Abeokuta, Nigeria were used to investigate the possible association of high outdoor gamma radiation exposure on reproductive abnormalities in the city. From the delivery record of 11,923 births in the period under study, a total number of 485 incidences of reproductive abnormalities were recoded. These incidences comprise 228 multiple births, 190 still births and, 67 premature births. Using the available terrestrial gamma radiation exposure data for the city and different reproductive abnormalities, regression assessment was carried out using the Pearson Product Moment (PPM) correlation statistics. The correlation showed that the incidences of reproductive abnormalities and the radiation dose levels were negatively correlated and correlation coefficient values were very low for each of the reproductive abnormalities considered. Factors such as socio-economic potentials of patients, dietary and other environmental factors may have substantial influence on the reproductive defects in the area other than radiation. However, the present study has added to the radiometric information needed in understanding the relationship between natural outdoor radiation exposure and occurrences of reproductive abnormalities in areas of high radiation in the country.
文摘The accelerator-generating 6.13 MeV pulsed Gamma by 19F（p, αγ）160 reaction usually synchronizes with an intense bremsstrahlung x-ray which has a maximum energy of 1 MeV. This paper proposes a new method, named the scattering and absorbing method, to diagnose the 6.13 MeV Gamma. This method includes two parts： the detector and a scatterer placed in front of the detector. The detector converts the Gamma to electrons and then collects the electrons by a scintillator. In order to restrain the interference of the low-energy background, the scintillator collects the electrons at a small angle. The scintillator is wrapped with electro-absorbing material to absorb the low-energy electrons generated by background x-rays. The theoretical sensitivity ratio of 6.13 MeV Gamma to 1 MeV x-rays is greater than 150. The scatterer is a pretreatment tool to scatter some background x-rays away from the radial beam before they enter the detector. By varying the length, the scatterer can reduce the background x-rays to an acceptable level for the detector.
文摘The paper first discusses shortcomings of classical adjacent-frame difference. Sec ondly, based on the image energy and high order statistic(HOS) theory, background reconstruction constraints are setup. Under the help of block-processing technology, background is reconstructed quickly. Finally, background difference is used to detect motion regions instead of adjacent frame difference. The DSP based platform tests indicate the background can be recovered losslessly in about one second, and moving regions are not influenced by moving target speeds. The algorithm has important usage both in theory and applications.
文摘Water samples from streams, hand-dug wells and boreholes in high background radiation areas in Abeokuta, Nigeria have been collected in order to determine the activity concentrations of 40K, 226Ra and 232Th in the samples as well as their physicochemical characteristics. These parameters were evaluated in order to deter-mine the quality of these water sources to the local population, who use these water resources for drinking and domestic activities. Measurements of radioactivity in the water samples were carried out using γ-ray spectroscopy, while standard chemistry methods were used for the physicochemical determinations of these quality parameters. A total of fourteen representative water samples from streams (7), boreholes (4), and hand dug wells (3) were collected for study. The determined activity concentrations of the radionuclides in these samples were used to calculate the effective dose to the population from due to ingestion of and drink-ing the locally available water. The total annual ingestion effective doses were found to vary between 115.00 ±1.15μSv and 1362.30 ±438.02 μSv. The physicochemical parameters where found to be lower than the prescribed standard safe limits in the water sources except for the nitrate and phosphate levels which were particularly high in the water samples from boreholes and hand-dug wells. The radiation effective ingestion dose due to ingestion of water from dug wells and streams was found to be higher than the dose due to inges-tion of water from borehole sources in the studied areas. The results obtained in this study, have been taken as a baselines for physicochemical parameters and activity concentrations of natural radionuclides in water samples within Odeda and Obafemi-owode parts of Abeokuta, Nigeria.
