The impact of gamma irradiation on Terminalia arjuna (T. arjuna), one of the potent medicinal plants for cardiac disease is described in this article. The seeds of T. arjuna were irradiated with different doses of gamma radiation ranging from 0 to 200 Gy using the ⁶⁰ Co source. The effect of gamma radiation on the growth and biochemical constituents were compared with the control plants. Germination speed at 25 Gy was found to be 0.65, which was double compared to the un-irradiated seeds. An increase in germination percentage, vigor index, and relative growth rate, in terms of dry weight was noticed at lower doses of the radiation treatment. The proline content increased with increasing doses. The chlorophyll content was found to have increased to 12.2 mg/g FW at 100 Gy compared to the control level of 8.44 mg/g FW. Increased phenolic content and radical scavenging capacity was observed at 25 and 150 Gy. Hence, lower doses of radiation treatment may be used to increase the germination, growth, and vigor, and also the enhancement of plant metabolites like proline and phenolics in T. arjuna.

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Carotenoids are the most common naturally occurring bioactive terpenoid pigments, which are commonly produced by a wide variety of plants and microbes. The present study was aimed to evaluate the antioxidant, antimicrobial and radio-protective properties of carotenoid pigments isolated from ultraviolet (UV)-C resistant Micrococcus spp. The UV-C resistant Micrococcus roseus and Micrococcus luteus were isolated from the soil samples of Savandurga hills region, Karnataka (India), and their pigments were identified as carotenoids based on spectral analysis. The UV-protective efficacies were determined by cling-film assay. Further, the antioxidant activities of pigments were evaluated by 2,2-diphenyl-1-picrylhydrazyl assay, and antibacterial activities by disc diffusion and broth microdilution assays. The optimum growth and pigment production by M. roseus and M. luteus were observed at temperature ranged between 35°C and 37°C, pH 7.0-8.0, NaCl 5.0-7.0%, and sucrose as major carbon and KNO ₃ as major nitrogen sources. In the present investigation, the isolated carotenoid pigments of M. roseus and M. luteus showed significant UV protective activity along with antioxidant (IC ₅₀ 3.5-4.5 mg/mL) and antibacterial (minimal inhibitory concentration 0.25-2.0 mg/mL) properties.

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In general, lead is used as shielding material for protection against radiation. In spite of its high density, lead is toxic and lead aprons are very heavy for personal shielding. Thus, there is a need for nontoxic, light, and environmental friendly radiation-shielding materials. Polymers cannot be effective against gamma radiation on their own. High-density metal wolfram carbide could be useful against gamma radiation, and boron carbide could also be useful for neutron shielding. In this study, high-density polyethylene, boron carbide, and wolfram carbide can be mixed in certain amounts and composite discs can be obtained in this way. According to results, a new shielding material is efficient for gamma radiation.

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Radon concentration has been estimated in drinking water samples of 17 selected locations in Amritsar city of Punjab, India. RAD7, an electronic solid state radon monitor has been used to evaluate the radon concentration in collected drinking water samples. The corresponding annual mean effective dose for ingestion and inhalation was calculated according to parameters introduced by UNSCEAR (2000) report. The radon concentration in drinking water samples has been found to vary from 0.53 ± 0.11 to 11.20 ± 1.40 Bql⁻¹ . The values of radon concentration in these samples were found below the recommended limit proposed by USEPA (1991) and European Commission (2001). The range of calculated annual effective dose varied between 1.45 and 30.57 ΅Svy⁻¹ . These values lie well within the safe limit prescribed by the WHO (2003) and European council (2005). The purpose of this study was to assess the radiological risk, if any, to human health due to consumption of drinking water that is available at Amritsar city.

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Uranium is a naturally occurring radioactive element that is both radiologically and chemically toxic. The presence of uranium in the aquatic environment is due to the leaching from natural deposits, release in mill tailings, the combustion of coal and other fuels, and the use of phosphate fertilizers that contain uranium. Intake of uranium through air and water is normally low, but in circumstances in which uranium is present in a drinking water source, the majority of intake can be through drinking water route. The uranium concentrations in ground water samples from Vishakhapatnam, India were estimated using laser fluorimetric technique and were observed to range from 0.6 to 12.3 ppb. The laser fluorimetry technique was found to be an excellent tool for direct measurement of uranium concentration in water samples at ultra-trace levels. The annual effective dose, cumulative dose for 70 years and the lifetime excess cancer risk from drinking of this water were calculated. The risks were low averaging only 10.6 × 10 ^-6 as none of the samples were observed to exceed the WHO recommended uranium concentration limit of 30 ppb.

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Human beings are continuously exposed to the radiations coming from terrestrial and extraterrestrial sources and inside their own bodies. This study presents the results of indoor and outdoor ambient gamma dose rates in and around granite regions of Shimoga District, and these measurements were carried out by using environmental radiation Dosimeter ER-709 which is a portable detector. By the measured average absorbed dose rates, annual effective dose (AED) has been calculated by a standard method. Results showed that the indoor and outdoor absorbed dose rates in air of Shimoga district ranged between 114.05 ± 2.11 to 332.6 ± 3.99 nGy/h and 87 ± 1.7 to 276.66 ± 4.76 nGy/h. The indoor and outdoor AED ranged between 0.559 to 1.631 mSv/year with an average value of 0.872 mSv/year and 0.106 to 0.339 mSv/year with an average value of 0.235 mSv/year, respectively. The calculated indoor and outdoor AEDs were found to be higher than the world average.

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Laser-Induced Fluorimetry has been used to measure the concentration of uranium in the ground water samples collected from the selected study locations of Bangalore city, India. The concentration of uranium in the collected water samples is found to be in the range 0.24 μg/l to 770.1 μg/l, with a geometric mean (GM) value of 18.9 μg/l. About 35% of the water samples show the concentration of uranium above the safe limit of 30 μg/l, set by the United States Environmental Protection Agency (USEPA). The annual effective dose associated with the ingestion of uranium by the adult population of the region has been estimated using the International Commission on Radiation Protection (ICRP) and World Health Organization (WHO) guidelines. Few physicochemical parameters of water such as pH, Total dissolved solids (TDS), major cations, major anions, and trace elements were also measured. The correlation coefficient among the measured parameters was determined to find the dependence, if any, on the concentration of uranium in the water samples.

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The exposure of human beings to ionizing radiation from natural sources is a continuously inescapable feature of life on earth. Direct measurement of absorbed dose rates in air has been carried out in many countries of the world during the last few decades. Such investigations are useful for the assessment of public dose rates. Indoor and outdoor gamma dose rates were evaluated along the coastal regions of Kollam district, Kerala, through direct measurement using portable gamma dosimeter, and analysis of soil sample for activity of ²³⁸ U, ²³² Th, and ⁴⁰ K concentration was carried out using gamma spectroscopy. Indoor and outdoor exposure rates, the annual effective dose (AED), and lifetime cancer risk of residents along the coastal regions of Kollam district, Kerala, were evaluated. The reduction coefficients were also calculated for the region. The mean indoor effective dose due to background gamma along the coastal region of Neendakara panchayath was found to be 7.56 mSvy⁻¹ which is larger as compared with the worldwide average of the AED of 0.48 mSv y⁻¹  and the outdoor mean effective dose of 4.83 mSvy⁻¹ . Estimated excess lifetime cancer risk (ELCR) from indoor AED equivalent ranges from 22.56 to 26.46 × 10⁻³ and ELCR from outdoor ranges from 14.95 to 16.65 × 10⁻³ . Excess average lifetime cancer risk estimate from all the values is found to be 20.56 × 10⁻³ , which is larger compared with the resulting worldwide average 0.25 × 10⁻³ .

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A systematic study was carried out to estimate the uranium concentration in the ground water around Kudankulam in Southern Tamil Nadu. The uranium concentration in ground water varies from 0.2 to 6.6 μg/l, with a mean value of 2.0 μg/l. The Quantalase uranium analyzer was used to measure the uranium concentration. These groundwater samples were analyzed for the water quality parameters such as pH, conductance, total dissolved solids (TDS), salinity, chloride, and sulfate. An attempt has been made to correlate the uranium concentration with the water quality parameters. It is observed that conductance, TDS, salinity, chloride, and sulfate show positive correlation with uranium concentration.

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Radon levels were measured in drinking water samples collected from Hanumangarh district of Rajasthan, India. The measurements were performed by RAD7 an electronic radon detector manufactured by Durridge Company Inc. The radon concentration in these samples is found to vary from (1.6 ± 0.6) to (5.4 ± 0.7) Bq/l with a mean value of (3.3 ± 1.1) Bq/l. These recorded values are compared with the safe limit values recommended for drinking water by various health and environmental protection agencies. The recorded values of radon concentration are within the safe limit of 11 Bq/l recommended by the US Environmental Protection Agency. The annual effective dose for ingestion and inhalation is also evaluated in this research. The estimated total effective dose varies from 4.29 to 14.47 μSv/year. The total effective dose in all locations of the studied area is found to be within the safe limit (0.1 mSv/year) recommended by World Health Organization and European Council.

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Assessment of natural radioactivity is very important from different points of view, especially for assessment of radiation exposure to human. In the present study, natural radionuclide concentrations of ²³⁸U, ²³²Th, and ⁴⁰K were measured by gamma spectrometry using HPGe detector in soil samples collected from Southwest coast of Kanyakumari district, Tamil Nadu. The radiological index parameters due to natural radionuclides such as radium equivalent activity, absorbed dose rate, annual effective dose rate, external hazard index, internal hazard index, and gamma index were calculated for the soil samples. All the calculated radiological index values are higher than world average values and the recommended safety limits. Multivariate statistical techniques such as Pearson correlation, principal component analysis, and cluster analysis were applied to know the relation between radionuclides and radiological parameters and to study the spatial distribution of radionuclides.

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In the present study, the radon mass and thoron surface exhalation rates have been measured in the soil samples collected from the villages of the Amritsar and Tarn Taran districts of Punjab using the active portable device, i.e., SMART RnDuo monitor to quantify the level of rate of radon and thoron exhalation. The average values of radon mass exhalation rate were 20 ± 7 mBq kg⁻¹ h⁻¹ and 23 ± 5 mBq kg⁻¹ h⁻¹ in Amritsar and Tarn Taran districts, respectively. Similarly, the average value of thoron surface exhalation rate was 664 ± 237 Bq m⁻² h⁻¹ and 1531 ± 1503 Bq m⁻² h⁻¹ in Amritsar and Tarn Taran districts, respectively.

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Strontium-90 is one of radioactive nuclear fallout products, can cause serious health effects. Efficient techniques are needed to remove radioactive strontium from contaminated persons. In this study complexation properties of the p-tert-butylcalix[4]arene has been evaluated against cold strontium nitrate. Ultra violet-visible (UV-vis) and fluorescence spectrophotometric techniques were used for the qualitative analytical screening and the inductively coupled plasma-atomic emission spectrometry (ICP-AES) technique used for the quantitative complexation of p-tert-butylcalix[4]arene with strontium nitrate. UV-vis, fluorescence spectroscopy and ICP-AES studies confirmed the complexation of p-tert-butylcalix[4]arene and strontium. Extraction study of strontium from picric acid by trans-chelation method proves that p-tert-butylcalix[4]arene is nearly 87% ± 3% effective. Complexation can be attributed to the cation-lone pair interaction and the bonding between the Sr ²⁺ and the hydroxyl group of the p-tert-butylcalix[4]arene implying its promise as a complexing agent for the removal of strontium.

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Accurate determination of uranium isotope ratio can act as an efficient fingerprint in the nuclear forensics to identify source and intended use of illicit trafficking of uranium material. In this context, a rapid chemical separation technique to isolate uranium from uranium ore sample was developed using commercial extraction chromatographic resin. Uranium isotope ratio was measured using thermal ionization mass spectrometry (TIMS). Standard reference material (NBS U010) was used for validating the accuracy and precision of isotope ratio measurement by TIMS. The method is successfully applied to a natural ore (uraninite ore) for the determination of naturally occurring uranium isotope ratio.

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Distribution studies of natural radionuclides in soil, statistical analysis of activity concentrations, and transfer factors (TFs) from soil to the vegetables grown in some selected farming communities within the Greater Accra Region in Ghana were carried out. The measurements were carried out through a gamma-ray spectrometry. The mean activity concentrations of ²²⁶Ra, ²²⁸Ra, and ⁴⁰K in the fertilized soils were 20.0 ± 3.9 Bq/kg, 39.0 ± 7.0 Bq/kg, and 143.6 ± 23.3 Bq/kg, respectively. For the nonfertilized soils, mean activity concentrations were found to be 12.07 ± 2.55 Bq/kg for ²²⁶Ra, 27.1 ± 6.3 Bq/kg for ²²⁸Ra, and 87.8 ± 18.5 Bq/kg for ⁴⁰K. These results were compared with reported ranges in the literature from other location in the world. The TF for ²²⁶Ra, ²²⁸Ra, and ⁴⁰K from fertilized soil to vegetables was evaluated. ²²⁶Ra TF values from fertilized soil to vegetables were found to be higher in lettuce in Farm 6. The highest TF for ⁴⁰K and ²²⁸Ra was found in cauliflower in Farm 4. ⁴⁰K TF was higher than those values reported in other studies. The activity concentration in fertilized and unfertilized soil exhibited slightly positively skewed, negatively skewed, leptokurtic, and platykurtic distribution in terms of skewness and kurtosis. The activity concentration of natural radionuclides in fertilized and unfertilized soil is statistically insignificant at 5% level of significance using independent t-test. Pearson's correlation coefficient exhibited a negative correlation between ²²⁶Ra and ²²⁸Ra in fertilized soil and ²²⁶Ra and ²²⁸Ra in vegetables but was statistically insignificant while ⁴⁰K in fertilized soil exhibited a positive correlation with ⁴⁰K in vegetables and was statistically significant at 5% level of significance with a coefficient of determination of 1%, 61%, and 10% for ²²⁶Ra, ⁴⁰K, and ²²⁸Ra, respectively.

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Naturally occurring ¹⁹⁷Au and ⁵⁸Ni foils were subjected to the neutron irradiation by placing them in a dry tube-I of Kalpakkam Mini reactor to produce gamma emitting ¹⁹⁸Au and ⁵⁸Co nuclear reaction products. The efficiency study of high-purity germanium detector corresponding to characteristic gamma energies 0.4118 and 0.8107 MeV of ¹⁹⁸Au and ⁵⁸Co was carried out by the methods of calibration of ¹⁵²Eu and covariance.

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The environment around us is radioactive due to background radiation emitted from the sky, earth's crust, food, water, and building materials. The human body gets exposed to radiation doses of about 82%, which are out of control; they arise from background radiation sources such as terrestrial, cosmic, and exposure to internal radiation. The background dose from cosmic radiation depends on the altitude, and regions with high altitude have high radiation doses. Natural radioactivity is present in the earth and is present in the different environment geological formations in the rocks and soils. Gamma radiation emitted from naturally occurring radioisotopes, such as ⁴⁰K and the radionuclides from the ²³²Th and ²³⁸U series and their decay products which exist as trace levels in all ground formations, represents the main external source of irradiation to the human body. Their concentrations in rocks, soils, and sands depend on the local geology of each region in the world. Naturally occurring radioactive materials have terrestrial-origin radionuclides since the creation of the earth. The dose rate of background radiation increases because of the existence of some quarries and springs in some regions which are called high-level background radiation regions. The type of construction materials used in houses can be affecting the dose rate of background radiations. Study of radioactivity in the environment is important to monitor the levels of radiation to which human is exposed directly or indirectly. Recently, several international studies have been done and different values were measured. In this article, a review and literature survey of background radiations such as terrestrial, cosmic, and food radiation was carried out.

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This paper reports the results of systematic studies aimed at generating a baseline database on the radiation levels and radionuclide distribution in the Gogi region, which has been identified as a prospective uranium mining region. A total of 39 villages in a 0-30 km radius zone of the Gogi region were covered under this study. The ambient gamma absorbed dose rates were measured using portable gamma dosimeters. The activity concentrations of ²²⁶ Ra, ²³² Th, and ⁴⁰ K in the soil samples were measured by the HPGe gamma spectrometry method. The ambient gamma absorbed dose rate varied in the range of 126-428 nGy h ^-1 , with a median value of 143 nGy h ^-1 . The activities of ²²⁶ Ra, ²³² Th, and ⁴⁰ K in the soil varied in the range of 5-176 Bq kg ^-1 , 9-687 Bq kg ^-1 , and 81-1493 Bq kg ^-1 , with the corresponding median values of 36 Bq kg ^-1 , 85 Bq kg ^-1 , and 859 Bq kg ^-1 , respectively. The study showed a highly non-uniform distribution of primordial radionuclides in the soil, with activity concentrations varying significantly within a small area. The results observed in the present study were compared with the literature values reported for other parts of India and the worldwide average values, and discussed.

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A significant proportion (10%) of the natural background radiation is of cosmic origin. Cosmic ray consists of gamma, protons, electrons, pions, muons, neutrons and low Z nuclei. Due to the geomagnetic effect, cosmic radiation levels at poles are higher. As a consequence, personnel working in Antarctica (or Arctic) are subjected to high level of cosmic radiation. The present study gives the details of the estimation of background radiation (neutrons, gamma and electrons) dose rate around the Indian station at Antartica named "Bharati" measured during 32 ^nd Indian scientific expedition to Antarctica (32 ^nd INSEA). The measurement was carried out by passive dosimeters such as TLDs and CR-39 and active dosimeter such as RadEye G portable gamma survey meter. Gamma and electron components were measured using TLDs and survey meter, whereas CR-39 SSNTDs and neutron sensitive TLDs were used for neutron measurements. These detectors were deployed at few selected locations around Bharati station for about 2΍ months during summer expedition. The neutron detectors used in the study were pre-calibrated with ²⁴¹ Am-Be fast/thermal neutron source. The fast neutron dose rate measured based on CR-39 detector was found to about 140-420 nSv/h. The gamma dose rate evaluated by TLDs/survey meter are in the range of 290-400 nSv/h.

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A study was carried out to estimate the ingestion dose for the general population residing around Kalpakkam nuclear site due to ⁴⁰K activity in the fresh and cooked food samples collected from the surrounding areas. For the estimation of specific activity of ⁴⁰K, food samples consisting of 31 numbers of market basket samples (MBS) and 33 numbers of duplicate diet samples (DDS) were collected, conditioned, and analyzed by gamma spectrometry. The annual effective dose (AED) received by the population was estimated based on ⁴⁰K activity in the food samples, food consumption data, and ICRP model. Uncertainty associated with the estimates was quantified based on the guide to the expression of uncertainty in measurement framework approach. The ⁴⁰K specific activity in MBS ranged from 10.44 ± 1.11 to 129.00 ± 13.64 Bq/kg fresh weight. Similarly, the ⁴⁰K specific activity in DDS ranged from 10.85 ± 1.10 to 60.71 ± 6.15 Bq/kg fresh weight. The AED due to the ingestion of ⁴⁰K estimated based on MBS was 93.81 ± 7.30 μSv/year. Similarly, the AED due to the ingestion of ⁴⁰K estimated based on DDS was 33.47 ± 0.79 μSv/year among males and 26.31 ± 0.62 μSv/year among females.

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Distribution of the natural radionuclides (²³⁸ U,²³² Th, and ⁴⁰ K) and their specific activities in sands and sediments of the Brahmaputra (Jamuna) river of Bangladesh together with mineral characteristics has been studied to assess the radiation levels as well as to develop a baseline database for comparison in the future in case of any change in the area under study due to anthropogenic activities. The radiological parameters of natural radioactivity were assessed calculating the radium equivalent activity, hazard index, the absorbed dose rate, and annual effective dose. The average activity concentrations of ²²⁶ Ra (²³⁸ U),²³² Th, and ⁴⁰ K in sand and sediment were found to be 59 ± 2 & 60 ± 2 Bq/kg, 113 ± 5 & 135 ± 5 Bq/kg, and 983 ± 42 & 1002 ± 43 Bq/kg, respectively. The calculated average absorbed dose rate and annual effective dose were found to be 150 nGy/h and 0.18 mSv/year respectively. These high values are associated with mineral content of the sediment. X-ray diffraction peaks of sand and sediment samples identify quartz, feldspar, rutile, zircon, monazite, uranium fluoride, hematite, kyanite, and uranium arsenide minerals to be present in the samples.

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Shielded LINAC hall has been built to accommodate a radio frequency quadrupole (RFQ) linear accelerator (LINAC) based pulsed neutron generator at RSD, IGCAR. The concrete neutron shield wall thickness for the LINAC hall is finalized by adopting NCRP-51 methodology. The dimensions of the trenches and labyrinth are decided based on the neutron generator installation requirements. As per the AERB safety criteria, the radiation dose levels in the occupancy area should be less than 1μSv/h. However, the refined dose estimate with the inclusion of actual trench and labyrinth dimensions indicates an increased dose rate of ~3.10 μSv/h in LINAC control room. Hence, the control room is declared as controlled area. Additional shielding has been proposed for the trenches and labyrinth to make the control room as full occupancy area. For designing the additional shielding, experimental and theoretical analyses are needed to estimate the radiation streaming through the trenches and labyrinth. To start with, the neutron streaming through trenches have been studied using 185 GBq (5Ci) ²⁴¹ Am-Be neutron source for qualifying the trenches. The ²⁴¹ Am-Be source position is selected at the trench entrance such that it contributes the same neutron flux as that of neutron generator. Neutron dose rate and spectral measurements have been carried out at five locations along the trench from the entrance (LINAC hall side) to the exit (Control room side) of the trench.The experimental results are validated with the theoretical calculations using Monte Carlo N particle (MCNP) code. The analysis shows that the trenches are having a dose reduction factor better than 800 with respect to that of entrance dose. The observed dose rate at the trench exit is found to be less than 450nSv/h. In this paper, both the theoretical and experimental neutron streaming analyses through the trenches of LINAC hall are presented.

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The natural radionuclides activity concentrations in beach sand of the extreme south of Bahia, Brazil, was measured by Gamma Spectrometry. The Radium Equivalent Activity, the external hazard index, the absorbed dose rate and the annual effective dose were assessed and compared with internationally published values for external dose and activity concentrations. The activity concentrations of ²²⁶ Ra, ²³² Th and ⁴⁰ K in beach sand ranged from 8.4 to 8,300 Bqkg ^-1 with a mean value of 910 Bq.kg ^-1 , from 21 to 18,450 Bqkg ^-1 with a mean value of 2,220 Bqkg ^-1 and from 3.4 to 3,110 Bqkg ^-1 with a mean value of 352 Bqkg ^-1 , respectively. The results indicate that the absorbed dose rates range from 21 to 14,450 nGyh ^-1 with mean value of 1,792 nGy.h ^-1 . The highest value of gamma dose rates among the studied beaches were found in Cumuruxatiba (14,450 nGyh ^-1 ). The annual effective dose range between 0.03 and 17.70 mSvy ^-1 , with the mean value of 2.20 mSvy ^-1 . In four studied beaches, the assessed outdoor annual effective doses are above the worldwide average of 0.07 mSvy ^-1 as reported by the United Nations Scientific Committee on the Effects of Atomic Radiation. Especially in the area of black sands, a big part of Cumuruxatiba beach, whose annual effective dose of 17.70 mSvy ^-1 is much higher than worldwide average.

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The activity concentrations of natural radionuclides in tailing enriched soil and sediment samples collected from two mining sites in southwest Nigeria are reported. The samples were analyzed by gamma spectrometry with low background NaI (Tl) detector. The activity concentrations of ⁴⁰ K, ²²⁶ Ra and ²³² Th in all the measured samples varied from 249.66 to 1459.25 Bq/kg, 7.62 to 50.31 Bq/kg and 12.68 to 234.18 Bq/kg, respectively in soil samples. For sediment samples, the values varied from 241.86 to 1590.40 Bq/kg, 9.86 to 74.8 Bq/kg and 15.47 to 145.46 Bq/kg for ⁴⁰ K, ²²⁶ Ra and ²³² Th, respectively. The results show that the mean activity concentrations of the radionuclides in soil and sediment of the study area are higher than their world-wide average crustal values. The mean concentration of ²³² Th is >6 times higher than that of ²²⁶ Ra in soil samples from Ijero mining site. This shows that ²³² Th is slightly enhanced in the soil from this location than ²²⁶ Ra. In order to evaluate the radiological hazards of the natural radioactivity, the radium equivalent activity, external hazard index, absorbed gamma dose rates and the annual effective dose rates were determined. All these hazard indices have mean values, which are within their acceptable limits but higher than their world average values.

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This overview gives a brief summary on the experimental results on three topics: (1) Thick target neutron yields produced by protons, deuterons, He and heavier ions having wide energy range from MeV to GeV, (2) spallation products production data together with induced activities by proton to U ion and (3) benchmark experiments on neutron shielding using various accelerators of MeV to GeV energies. These three items are essentially important for radiation safety of accelerator facility.

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