Gamma radiation and radon levels in Mexico City dwellings

Gamma exposure rate and radon levels were measured in 75 single-family dwellings in Mexico City in order to correlate them with local environment. Radon monitoring was performed both indoors and outdoors using a continuous working level monitor for short-lived radon decay products; the gamma exposure rate was measured using CaSO₄: Dy+PTFE. The results obtained show a log-normal distribution. The mean indoor radon concentration is lower than 45 Bq/m³ and the mean indoor gamma exposure rate was 11.29 R/h.     

Prompt determination of evacuee radiation dose from a nuclear event

In anticipation of a nuclear detonation, techniques to quickly assess the radiation exposure of evacuees should be developed. Based on experience relating neutron radiation exposures to activation products, measurement of activation products can be performed in a few minutes. Personal items exposed to significant levels of radiation allows neutron dose assessment via the activation products. This approach allows prompt collection of important data on human exposure following a nuclear attack. Data collected will facilitate triage decisions for emergency medical treatment to ameliorate the radiation effects on exposed individuals. Activation experiments with everyday items exposed to a neutron source are presented.     

Assessment of gamma-ray emissions from natural and manmade decorative stones

Decorative stones (32 natural and 18 manufactured) and five ceramic tiles that are used in home interiors were measured with gamma-ray spectrometry, to identify and quantify the naturally occurring radionuclides. Activity concentrations of the radioisotopes varied by more than two orders of magnitude across the stone samples, with maximal levels of 3380, 850, and 2130 Bq/kg, for ²³⁸U, ²³²Th, and ⁴⁰K, respectively. A radiation index and measurements with a radiation meter established that the annual effective dose rates due to a 1 h/day exposure to gamma rays emitted by the granite samples were often low, but can occur as high as 1 mSv/year.     

Assessment of terrestrial gamma radiation dose rate (TGRD) of Kelantan State,Malaysia: Relationship between the geological formation and soil type to radiation dose rate

Terrestrial gamma radiation dose rates (TGRD) of Kelantan State were measured in situ using a portable [NaI(TI)] micro roentgen (µR) survey meter. The TGRD rates ranged between 44 and 500 nGy h^?1 with a mean value of 209 ± 8 nGy h^?1. The distribution of these measurements in various districts of the state shows the statistically the influence of geology and soil types on the dose rate values. The data obtained could be used in formulating safety standard and radiological guidelines.     

Radiological assessment of natural radionuclides in soil from playgrounds in Southwestern Nigeria and evaluation of radiation dose

Journal of Radioanalytical and Nuclear Chemistry - The activity concentrations of natural radionuclides in soil from playground were determined by gamma spectrometry using NaI(Tl) detector. Annual...     

Effect of dose and dose rate of gamma radiation on catalytic activity of catalase

Catalytic activity of gamma irradiated catalase from bovine liver was studied for hydrogen peroxide decomposition at constant temperature and pressure. The measurement was performed at temperatures 27, 32, 37, 42 and 47 °C. Solutions containing 1 and 0.01 g dm⁻³ of catalase in phosphate buffer were used for the study. Repeatability of both sample preparation and kinetics measurement was experimentally verified. Rate constants of the reaction were determined for all temperatures and the activation energy was evaluated from Arrhenius plot. Gamma irradiation was performed using ⁶⁰Co radionuclide source Gammacell 220 at two different dose rates 5.5 and 70 Gy h⁻¹, with doses ranging from 10 to 1000 Gy. The observed reaction of irradiated and non-irradiated catalase with hydrogen peroxide is of the first order. Irradiation significantly decreases catalytic activity of catalase, but the activation energy does not depend markedly on the dose. The effect of irradiation is more significant at higher dose rate.     

Evaluation of dose rate distribution in objects irradiated in large gamma sources

The codes DOSKMF2 and ISORADL makes it possible to describe numerically as well as graphically γ-irradiation facilities by means of dose rate values for a chosen set of points of interest in the radiation field or by means of dose rate isocurves for chosen crossections of the radiation field, respectively. The structure of DOSKMF2 is briefly described.The combination of this calculation procedure and experimental dose rate determination makes it possible to evaluate the radiation fields in existing γ-irradiators.A design procedure for γ-irradiators using the computer tools is briefly presented.     

Application of zeolitic rocks in the environment: assessment of radiation due to natural radioactivity

Journal of Radioanalytical and Nuclear Chemistry - The 238U, 226Ra, 210Pb, 228Ra, 228Th and 40K concentrations have been measured beside to radon emanation factor due to sample granulometric using...     

Distribution patterns of gamma radiation dose rate in the high background radiation area of Odisha,India

Journal of Radioanalytical and Nuclear Chemistry - Absorbed dose rates in air for 20 residential areas in Odisha were measured using a vehicle-mounted NaI(Tl) scintillation spectrometer. The...     

MOS ionizing radiation dosimeters: from low to high dose measurement

Metal-oxide-silicon dosimeters with a very thick gate oxide in a stack-connected configuration are studied with respect to their capability to measure a low dose. It is shown that if the temperature is controlled to ±5°C during reading a dose as low as 10⁻⁴ Gy can be measured with 10% accuracy.     

Radioactivity from natural,industrial, and other sources

Natural radioactivity and the use of x-rays and radioactive substances in the practice of medicine are the main sources of radiation exposure to the general public. The protection standards used in all countries are based on the recommendations of the International Commission on Radiological Protection. These standards are being observed by the nuclear industry and have succeeded in protecting both nuclear workers and members of the general public. The dose received from nuclear power generation is a tiny fraction compared to the doses received from nature and medical practice.However, a great gap exists between the risks of low-level radiation exposure as perceived by the public and the risk that actually exists. This is true not only concerning nuclear power generation, but also with respect to the need to dispose of both high-level and low-level wastes. In addition, the dangers of plutonium have become distorted in the public mind. Fifty years of research into the biological effects of plutonium have been reassuring and an excellent safety record has been achieved in the industrial production of this material.     

Gamma radiolysis of EDTA in a simulated, mixed nuclear waste

The effects of γ-irradiation on EDTA degradation have been studied. A simulant of Hanford's complex concentrate was prepared by adding EDTA to an inorganic matrix which was formulated based on past analyses of the actual Hanford complex concentrate waste. For, the radiolysis study, aliquots of the simulated waste were then γ-irradiated. Each waste sample was analyzed to monitor the appearance of degradation products. Based on the results of this study, an assessment of the impact of EDTA degradation on the management of mixed wastes is offered.     

Outdoor absorbed dose rate in air in relation to airborne natural radioactivity and meteorological conditions at Bucharest (Romania)

Summary The results of environmental absorbed dose rate measurements performed over a 3-year period (1996-1999) at the Bucharest Environmental Radioactivity Surveillance Station are presented. The outdoor absorbed dose rate levels were analyzed in connection to airborne natural radioactivity and meteorological parameters, such as precipitation, air temperature and pressure.The minimum values were recorded in winter and the maximum values at the end of summer or beginning of autumn, mainly as a consequence of changes in weather and soil conditions (rain, ground moisture, snow cover).Significant statistical correlations were obtained between the outdoor absorbed dose rate and the air temperature and atmospheric pressure, respectively.     

Soil radon and gamma-dose rate at a coastal region in Mexico

Soil radon and the gamma-dose rate have been determined along the Guerrero coast of Mexico, using track detectors, LR 115 Type II and thermoluminescent CaSO₄:Dy detectors. Mineralogical analyses were done and ²³⁶Ra and ⁴⁰K specific activities were measured in the rock samples. The results indicate a good correlation between the response of average gamma-dose rate versus radon concentration in the soil. Differences in the radon levels, in the activity concentrations in the rocks and in the local seismicity defined two geographical zones where the number of seismic events, the average radon and the average gamma-dose rate were correlated.