Spatial variations of radon and helium concentrations in soil-gas across the Shan-Chiao fault, Northern Taiwan

Spatial variability of gases like radon and helium in soil-gas can be used for seismic surveillance and for finding fault system. The present study is aimed at determining a possible connection between eventual radon/helium anomalies and active fault. Radon and helium concentrations in subsurface soil-gas have been monitored along the Shan-Chiao fault, Northern Taiwan. Twenty transverse profile surveys have been conducted across the fault, where 235 and 125 samples were collected for helium and radon analyses, respectively. The data analysis clearly reveals anomalous values of both radon and helium along the fault. To find the fault system, where the migration of gases is governed by advection, it is essential to identify the anomalies in both radon and helium together. The consistency of this pattern confirms that radon and helium together can act as a powerful tool for the detection and mapping of active fault zones.     

Correlations between radon in soil gas and the activity of seismogenic faults in the Tangshan area,North China

The spatial variation of soil gas radon values were correlated with the seismogenic faults and earthquakes in the Tangshan area (north China). Radon concentrations were measured at 756 sites in an area about 2500 km² from April to May 2010. The background and anomaly threshold values calculated were 4730.4 Bq/m³ and 8294.1 Bq/m³, respectively. Radon concentrations highlight a decreasing gradient from NE to SW in the area. Higher values mostly distributed in the NE sector of the Tangshan fault and the Luanxian fault where the Tangshan (Ms 7.8), and Luanxian (MS 7.1) earthquakes occurred in 1976 and 17 earthquakes with MS = 3.0 occurred in this area since 2005. Radon values illustrated a close relation with the shallow fault trace and earthquake activity in the area. The active fault zones and the associated fractures formed by the larger earthquakes, act as paths for radon migration.     

Relation between Fresnel transform of input light field and the two-parameter Radon transform of Wigner function of the field

This paper proves a new theorem on the relationship between optical field Wigner function's two-parameter Radon transform and optical Fresnel transform of the field, i.e., when an input field ψ( x') propagates through an optical [ D( -B) ( -C) A] system, the energy density of the output field is equal to the Radon transform of the Wigner function of the input field, where the Radon transform parameters are D,B. It prove this theorem in both spatial-domain and frequency-domain, in the latter case the Radon transform parameters are A,C.     

Variation of radon concentrations in soil and groundwater and its correlation with radon exhalation rate from soil in Budhakedar, Garhwal Himalaya

Radon was measured in soil-gas and groundwater in the Budhakedar area of Tehri Garhwal, India in summer and winter to obtain the seasonal variation and its correlation with radon exhalation rate. The environmental surface gamma dose rate was also measured in the same area. The radon exhalation rate in the soil sample collected from different geological unit of Budhakedar area was measured using plastic track detector (LR-115 type II) technique. The variation in the radon concentration in soil-gas was found to vary from 1098 to 31,776 Bq.m⁻³ with an average of 7456 Bq.m⁻³ in summer season and 3501 to 42883 Bq.m⁻³ with an average of 17148 Bq.m⁻³ in winter season. In groundwater, it was found to vary from 8 to 3047 Bq.l⁻¹ with an average value 510 Bq.l⁻¹ in summer and 26 to 2311 Bq.l⁻¹ with an average value 433 Bq.L⁻¹ in winter. Surface gamma dose rate in the study area varied from 32.4 to 83.6 μR.h⁻¹ with an overall mean of 58.7 μ-R.h⁻¹ in summer and 34.6 to 79.3 μR.h⁻¹ with an average value 58.2 μR.h⁻¹ in winter. Radon exhalation rate from collected soil samples was found to vary from 0.1 × 10⁻⁵ to 5.7 × 10⁻⁵ Bq.kg⁻¹.h⁻¹ with an average of 1.5 × 10⁻⁵ Bq.kg⁻¹.h⁻¹ in summer season and 1.7 × 10⁻⁵ to 9.6 × 10⁻⁵ Bq.kg⁻¹.h⁻¹ with an average of 5.5 × 10⁻⁵ Bq.kg⁻¹.h⁻¹. A weak negative correlation was observed between radon exhalation rate from soil and radon concentration in the soil. Radon exhalation rate from the soil was also not found to be correlated with the gamma dose rate, while it shows a positive correlation with radon concentration in water in summer season. Inter-correlations among various parameters are discussed in detail.      

Relationships between radon anomalies and seismic parameters in N-W Himalaya, India

Radon data accumulated during 1992–1999 in the grid (30–34°N, 74–78°E) in N-W Himalaya have been anlaysed vis a vis seismic data recorded in the same area, supplied by Indian Meteorological Department (IMD) network. In general, there is a positive correlation between the total radon emission and the microseismicity in the area under investigation. The earthquake magnitude has moderate positive correlation with epicentral distance and low positive correlation with amplitude of radon precursory signal, whereas both show low negative correlation between them.

Empirical scaling relations are proposed using the best fit straight line from the log-linear graphs between magnitude of the events and log of the product of amplitude of radon anomaly and epicentral distance. The error between the recorded and calculated magnitude is also taken into account. The error range is higher at lower epicentral distances and magnitudes, showing that the local geology and tectonics have predominant influence on radon signals.     

Seasonal and location dependence of indoor and soil radon concentrations in two villages,Najran region,Saudi Arabia

Seasonal (winter-summer) indoor and soil radon comparison is made in two villages in Najran region, south west of Saudi Arabia, using CR-39 Dosimeter. Summer indoor radon concentrations were measured in the villages of Fara Al-Jabal and Hadadah. The respective winter-summer average values of 42 ± 4 Bq m⁻³ and 74 ± 5 Bq m⁻³ are measured in Fara Al-Jable village and the average values of 47 ± 4 Bq m⁻³ and 76 ± 5 Bq m⁻³ are measured in Hadadah village. The respective winter-summer soil values are 1.40 ± 0.21 kBq m⁻³ and 0.99 ± 0.04 kBq m⁻³ in Fara Al-Jabal village while those measured in Hadadah village are 2.90 ± 0.17 kBq m⁻³ and 1.40 ± 0.66 kBq m⁻³. Indoor radon levels are found to be seasonal dependent while that of soil are found seasonal and location dependent. Meteorological and geological factors are expected to have caused the measured significant differences in radon levels in dwellings and soil in the two villages.     

Variations of soil radon and thoron concentrations in a fault zone and prospective earthquakes in SW Taiwan

An automatic station for soil gas monitoring was set up on an active fault zone of SW Taiwan. After more than one year of continuous measurements, some spike-like anomalous high radon and thoron concentrations could be observed. A similar soil radon spectrum was also obtained from an independent monitoring station, which was only 100 m away. These anomalous peaks usually occurred a few days or weeks before the earthquakes (M_L4.5). This indicates that variations of both soil radon and thoron can serve as useful tools for earthquake surveillance, esp. at fault zones.     

An attempt to determine the tritium, Na, Cl and radon in territory of mud volcano in Taman

Little is known about the radio-isotopic geochemistry of mud volcanoes in the Taman area, Krasnodar region, in the tectonic active zone of the Caucasus range. In 1998, we have started the determination of radon in soil air using solid state nuclear track detectors on a monthly basis. Tritium was determined out of water sampled at the mud volcano vents by means of both mass spectrometry and liquid scintillation. ²²Na, ³⁶Cl were also determined by means of a low background gamma spectrometer placed at a depth of 50 m in our underground laboratory. It was found that mud volcano fluids are of partial deep origin.     

A comparative study of indoor radon level measurements in the dwellings of Punjab and Himachal Pradesh, India

The LR-115 type-II plastic track detector has been used for measuring the indoor radon levels in the dwellings of some villages of Punjab and Himachal Pradesh. In Punjab, the villages surveyed are Rampura Phul, Lehra Mahabat and Pitho (villages in Bathinda district), and Amritsar city. The average indoor radon levels in these areas are found to vary from 64 to 152 Bq/m³, which are quite within the safe limits recommended by International Commission on Radiological Protection (Ann. ICRP 23(2)). The indoor radon levels have also been measured in the dwellings of Hamirpur district of Himachal Pradesh. The villages surveyed in this area are Nukhel, Badarn, Galore-Khas, Har-Upper, Tikker Brahamana and Awah-Lower where radon concentration has been found to vary from 261 to 724 Bq/m³. These values are higher than the recommended limit.     

Baseline studies of radon/thoron concentration levels in and around the Lambapur and Peddagattu areas in Nalgonda district, Andhra Pradesh, India

Studies conducted by Atomic Minerals Directorate of Exploration and Research (AMD) of Hyderabad, India had established the presence of higher concentrations of uranium in Lambapur and Peddagattu areas of Nalgonda district, AP, India and it was estimated that it could be a viable source for commercial extraction. The envisaged extraction process involves dispersion of radioactive particulate matter into atmosphere. Environmental radioactive studies in and around proposed mining areas at this point of time will be extremely useful for establishing base line data before a large scale uranium extraction process comes into existence. To this end, Solid State Nuclear Track Detectors were installed to evaluate indoor radon and thoron concentration levels in the dwellings of the area. The geometric means of radon and thoron concentration levels were found to be (7.1±0.2)×10¹ and (6.7±0.3)×10¹ Bq/m³, respectively. Simultaneously, natural background radiation measurements were also made and these levels are found to vary from 770 to 3995 μGy/y in the spatial distribution.     

Study of indoor radon and thoron progeny levels in surrounding areas of Nalbari, Assam, India

With the growing understanding of the role of radon and its daughter products as major sources of radiation exposure, the importance of large number of estimation of radon concentration in various parts of the country is realized. Inhalation of radon, thoron and their decay products is the major source of the total radioactive dose received by the human population from natural radiation. The indoor radon and thoron progeny levels in Nalbari area of Assam are studied by using the LR-115 (type II) Solid State Nuclear Track Detector in Plastic Twin Chamber dosimeter. Radon and thoron progeny levels in different types of dwellings for one full calendar year are presented in this paper. For Assam Type (A.T.) houses, indoor radon progeny concentrations vary from 0.17 to 0.64 mWL with an annual geometric mean of 0.27 mWL and that for Reinforced Cement Concrete (R.C.C.) houses vary from 0.22 mWL to 0.60 mWL with the annual geometric mean of 0.37 mWL. The thoron progeny levels in A.T. houses also vary from 0.01 to of 0.05 mWL with an annual geometric mean of 0.02 mWL and that for R.C.C. houses vary from 0.02 to 0.08 mWL with the annual geometric mean of 0.04 mWL.      

Study of uranium, radium and radon exhalation rate in soil samples from some areas of Kangra district, Himachal Pradesh, India using solid-state nuclear track detectors

LR-115 plastic track detectors have been used for the measurement of radon exhalation rate and radium concentration in soil samples collected from some villages of Kangra district, Himachal Pradesh, India. Uranium concentration has also been determined in these soil samples using fission track technique. Radium concentration in soil samples has been found to vary from 11.54 to 26.71 BqKg⁻¹, whereas uranium concentration varies from 0.75 to 2.06 ppm. The radon exhalation rate in these samples has been found to vary from 15.16 to 35.11 mBqKg⁻¹ h⁻¹ (502.12 to 1162.64 mBqm⁻² h⁻¹).     

Radiation dose-dependent risk on individuals due to ingestion of uranium and radon concentration in drinking water samples of four districts of Haryana,India

Uranium gets into drinking water when the minerals containing uranium are dissolved in groundwater. Uranium and radon concentrations have been measured in drinking water samples from different water sources such as hand pumps, tube wells and bore wells at different depths from various locations of four districts (Jind, Rohtak, Panipat and Sonipat) of Haryana, India, using the LED flourimetry technique and RAD7, electronic silicon solid state detector. The uranium (²³⁸U) and radon (²²²Rn) concentrations in water samples have been found to vary from 1.07 to 40.25?µg?L^?1 with an average of 17.91?µg?L^?1 and 16.06?±?0.97 to 57.35?±?1.28?Bq?L^?1 with an average of 32.98?±?2.45?Bq?L^?1, respectively. The observed value of radon concentration in 43 samples exceeded the recommended limits of 11?Bq?L^?1 (USEPA) and all the values are within the European Commission recommended limit of 100?Bq?L^?1. The average value of uranium concentration is observed to be within the safe limit recommended by World Health Organization (WHO) and Atomic Energy Regulatory Board. The annual effective dose has also been measured in all the water samples and is found to be below the prescribed dose limit of 100?µSv?y^?1 recommended by WHO. Risk assessment of uranium in water is also calculated using life time cancer risk, life time average daily dose and hazard quotient. The high uranium concentration observed in certain areas is due to interaction of ground water with the soil formation of this region and the local subsurface geology of the region.     

Relation between the Superconducting Transition Temperature and the Axial Ratio in R Ni 2 B 2 C ( R =Y,Ho, Er,Tm, Lu) Under High Pressure

The effect of pressure on the lattice parameters of R Ni 2 B 2 C ( R = Y, Ho, Er, Tm, Lu) has been measured in order to investigate the relation of T C to axial ratio c/a in the tetragonal lattice or the cohesive properties of these materials. The large anisotropies are observed in the lattice compression curves especially for R =Ho and Tm; the c -axis is more compressible than the a -axis. On the other hand, the anisotropy in the lattice compression is found to be relatively small for R =Y and Lu. The close relation between T C and c/a is pointed out particularly for R =Ho.     

Statistical relationship between activity concentrations of radionuclides 226Ra, 232Th, 40K,and 137Cs and geological formations in surface soil of Jordan

An extensive study was conducted to determine the activity concentrations of natural and artificial radionuclides ²²⁶Ra, ²³²Th, ⁴⁰K, and ¹³⁷Cs in soil samples of each governate of Jordan. A total of 370 samples have been measured using a high-purity germanium detector. The activity concentration for ²²⁶Ra, ²³²Th, ⁴⁰K, and ¹³⁷Cs has mean values of 42?±?3, 23?±?3, 309?±?21, and 3.7?±?0.9 Bq kg^–1, respectively. The highest mean activity concentration for ²²⁶Ra was found to be 138?±?4 Bq kg^–1 in the Alkarak governate. In the Ajloun and Jarash governates, the highest mean activity concentration was 35?±?3 Bq kg^–1 for ²³²Th, and 14.2?±?1.9 Bq kg^–1 for ¹³⁷Cs, respectively. Geological influence on the activity concentrations was investigated using the one-way analysis of variance (ANOVA) and independent samples. The ANOVA results indicate that there are strong significant differences between the activity concentrations of ²³²Th, ⁴⁰K, and ¹³⁷Cs based on geological formations the radionuclides occur. The main contribution to gamma dose rate was due to ²²⁶Ra activity concentration. Radium equivalent and external hazard index are associated with a mean value of 98 Bq kg^–1, and 0.266, respectively.     

Nitrogen-induced broadening and shifts of rotation-vibrational lines in the fundamental, first, second and third overtone bands of HI

We report experimental results on the previously unknown broadening and shifting coefficients in the fundamental and three overtone vibration-rotation bands of the HI molecule in mixtures with nitrogen gas. Our data are compared with the previously published results for the fundamental bands of the HF and HCl molecules. It is shown that the line shifts are dominated by the vibrational dependence of the isotropic part of the intermolecular interaction potential.     

电磁学中国际单位制和实用单位制之间的转换

给出了电磁学中通用的国际单位制及相当流行的实用单位制之间的简单并且便于记忆及使用的转换方式。     

Comparison of active and passive radon survey in cave atmosphere,and estimation of the radon exposed dose equivalents and gamma absorbed dose rates

Radon (²²²Rn) measurements were conducted in the Pileki Cave with Radim 3A Active Radon Monitor equipment. Measurements were also done with the passive sampling method with CR-39 nuclear track detectors by exposing them for three months in the cave. Radon concentrations obtained from the active and passive sampling methods showed that, firstly, the concentrations inside the cave measured by the latter method differed greatly due to high humidity levels up to 88%. The total inside radon exposure dose equivalent people were subjected to was estimated to be 19?µSv a^?1 for visitors and 24,065?µSv a^?1 for guides. The gamma absorbed dose rates were determined for inside and outside the cave. The dose rates were calculated by means of using the ²²⁶Ra, ²³²Th and ⁴⁰K activity concentrations and by means of real-time measurements. The gamma absorbed dose rates were found to be much higher than the value of 55?nGy?h^?1 given by UNSCEAR. In addition, the mineralogical compositions and elemental analyses of samples taken from the cave were determined by XRD and WD-XRF methods.     

Seasonal variations of radon and the radiation exposure levels in Nerja cave, Spain

²²²Rn concentrations in the air in Nerja cave (Spain) (3° 52′35′′W 36° 43′50′′N) were measured by continuous monitoring using Alpha-Guard, Genitron instrument equipment. The ²²²Rn measurements were carried out for a complete annual cycle in the different halls: Vestibule hall from July 2003 to June 2004, Ballet hall from July 2004 to June 2005 and Mirador hall from July 2005 to June 2006. Starting from the entrance of the cave we successively find the Vestibule hall, the Ballet hall and the Mirador hall. The range of ²²²Rn levels were of 8–627 Bq m⁻³ for the Vestibule hall, 28–575 Bq m⁻³ for the Ballet hall and 38–578 Bq m⁻³ for the Mirador. The aim of this study was to detect seasonal variation patterns of ²²²Rn concentrations. The seasonal variations of ²²²Rn concentrations are discussed in relation to various meteorological factors measured inside and outside the cave. The radiation exposure levels for workers and tourists with different equilibrium factors have been evaluated. The radiation exposure levels for workers and tourists only represent a low percentage of the exposure guides for the general population.     

Determination of concentrations of fissionable elements in the Black Sea sediment samples before and after Chernobyl using neutron radiography method

The fissionable elements content, particularly uranium, of the Blask Sea sediment samples obtained in 1978 and 1989 as surfacial sediments were determined by neutron radiography using solid state nuclear track detectors (SSNTDs).