Sabbir Ahamed. Zawar Hussain. Omar Daraghmeh. Dr-Charu Lata. Show More. Views Total views. Actions Shares. No notes for slide. Radioactivity 1. Radioactivity 2. Alpha Decay 8. Alpha Decay 9. Alpha Decay Transmutation is the changing of one element into another.
Click Here With the loss of an electron, the nucleus must have an extra positive charge, so in this case the number of protons is 7, which is Nitrogen. Beta Decay We will discuss this more in a later chapter. This type of decay is also called beta negative, or negatron decay. Negatron decay occurs when the isotope lies above the stable isotope line; there are too many neutrons compared to the number of protons.
These isotopes lie below the stable isotope line. Usually, this is one of the innermost electrons. The electron disappears and a proton becomes a neutron in the process. A neutrino is emitted in electron capture decay. This process has been detected by the emission of x-rays due to other orbital electrons jumping down to fill in the lower energy levels and releasing energy of that energy.
Electron Capture The decay of a nucleus by the emission of a gamma ray is much like the emission of photons by excited electrons. Gamma Decay The nucleus is them said to be in a metastable state and is called an isomer. The nucleus can also return to its ground state by a process called internal conversion, where no gamma ray is emitted. The nucleus interacts with an electron and loses its energy in that way. The electron then loses the energy as an x-ray.
X-rays come from atom- electron interactions, while gamma rays come from nuclear processes. The half life of an isotope is the time it takes half of the original sample to decay The precise relationship is 0. What is its half life? How much remains of an initial g sample after 6 hours?
All living plants and animals absorb CO2 from the air and use it to synthesize organic molecules. Most of these atoms are carbon, but a small amount are carbon The amount of carbon in the atmosphere has remained fairly constant over thousands of years, even though carbon has a half life of years. It has stayed constant because neutrons in cosmic radiation collide with particles in the atmosphere.
Collisions with nitrogen particles produce carbon through n. Animals continuously eat plant matter, so they receive a fresh supply of carbon for their tissues. Once the organism dies, there is no longer a fresh supply of carbon, and the amount of carbon begins to decline due to radioactive decay. Therefore, different substances separate from one another.
Scientists can tell from the number of each type of atom how long that particular rock has been formed. Detecting Radiation Radioactive particles are far too small to be detected by our senses; it is for this reason that scientists have created a variety of ways to detect the alpha, beta, and gamma decays of nuclei. Geiger counter 2. Scintillation counter 3. Liquid scintillators 4.
Semiconductor detector All rights reserved. E-mail address: [email protected] H. This paper, which is a further investigation on naturally occurring radioactive material NORM Hamlat et al. Materials and methods 2. Hamlat et al. Portable radiation measuring instruments with appropriate probes for on site assessments of penetrating gamma ray activities were used. Gamma ray spectrometry analysis Collected samples were stored in vials for scales and in polyethylene containers for liquids for at least three weeks to allow for the equilibrium of Ra with its decay products Bi and Pb.
The gamma ray measurements on samples were carried out using high purity Germanium HPGe detectors 10 cm Pb shielding with a resolution of 1. The counting time was 2 h for scales and 24 h for the rest of the samples. For the analysis, the keV gamma ray emitted by Ra was used. The natural background level was subtracted from each recorded spectrum.
Assessment of the occupational doses Assessment of the occupational doses of NORM involves the analysis of the exposure pathways. Results and discussion 3. These results of Ra activity concentrations range from 5. The mean activity concentration of Ra in produced water was This is very close to the mean value of 9.
Also, our results agree with those reported elsewhere in the literature Stephenson, ; Strand et al. The results of the investigations carried out on production water in other countries, show a much wider range of activity concentrations Table 1 Bloch and key, ; Testa et al. Activity levels in crude oil The results of the analysis of the crude oil samples collected from several wells are given in Table 1b.
The results are compared to those reported in the literature. The activity levels obtained in our study range from 0. The maximum single measurement, 0. Activity levels in deposits Samples of deposits were taken from surface equipment during normal operations and repairs. The results of the measurements are shown in Table 1c and d, respectively.
This is close to the reported range measured by Holland in North Sea, but higher than those mentioned by other authors. The highest single measurement of Ra in our study is very close to the maximum value reported by Holland and approximately an order of magnitude higher than other reported values. Radiation exposure Approximately, measurements were performed at the surface 1 cm of various components and equipment. The results of these measurements are shown in Table 2. The gamma ray dose rates ranged from background 0.
This is very close to the reported range measured by Wilson et al. Radiation levels obtained at oil and gas facilities are presented in Table 3. The gamma ray dose rates in our study for oil plants varied between 0. However, the measurements in gas plants were found to range from 0.
Assessment of the occupational doses The occupational doses depend on the dose rates and the working time spent during normal activities and repairs. For normal activities in oil sector, the dose at 1 m from the pipes and separators, storage tanks and well head are, 0.
Furthermore, our results are comparable to those reported during onshore decontamination in the USA and UK Reed et al. Doses from inhalation are generally trivial and became only Max. Consequently, neither of these pathways is considered further. Conclusion NORM is an acknowledged problem in extractive industries world wide, particularly in the oil and gas industry. The oil industry often has higher radiation levels than those in the gas industry.
However, the doses to workers appear to be lower than the dose limit for occupational exposure Lysebo and Strand, ; Strand et al. High activity concentrations of Ra are found in scale. Activity concentrations in production water are higher than those in crude oil. It has been assumed that NORM originated with formation water. However, it is estimated that for the oil and gas industry, M.
Acknowledgements The authors are very grateful to the H. Department of D. References Anderson, B. Baton Rouge State Times. Anon, Study of produced water in the state of Louisiana, State of Louisiana. Baton Rouge. Bassignani, A. Radioactive scales in Oil and Gas production centres. Petrol Engng. BAZ, Bloch, S. Degrange, J. Development of a methodology for assessing occupational exposure at workplaces where materials are processed which contain enhanced levels of natural radioanuclides.
Dixon, D. Hazard assessment of work with ores containing enhanced levels of natural radioactivity. Radiological Protection Bulletin No.
Diyashev, R.
0コメント