A new design of square lattice photonic crystal fiber is made by borosilicate material with circular and square air holes to minimize dispersion

Volume 2 Issue 10 (October 2014

Radon exhalation rate in Chhatrapur beach sand samples of high background radiation area and estimation of its radiological implications

Chhatrapur beach placer deposit, situated in a part of the eastern coast of Orissa, is a newly discovered high natural background radiation area (HBRA) in India. The sand samples containing heavy minerals, were collected from Chhatrapur region by the grab sampling method at an interval of ~ 1 Km. Radon exhalation rates were measured by "Sealed Can Technique" using LR-115 type type II in the sand samples containing heavy minerals collected from the beach. Radon activity is found to vary from 1177.1 to 4551.4 Bq m–3 whereas the radon exhalation rate varies from 423.2 to 1636.3 mBq m–2h–1 with an average value of 763.9 mBq m–2h–1. Effective dose equivalent in sand samples estimated from exhalation rate varies from 49.9 to 193.0 μSv y–1 with an average value of 90.1 μSv y–1. From the activity concentration of 238U, 232Th and 40K computed radium equivalent is found to vary from 864.0 to 11471.5 Bq kg–1 with an average value of 3729.0 Bq kg–1. External hazard index, Hex range from 2.3 to 31.0 with a mean value of 10.1, which is quite high. This value supports the conclusion based on high mean absorbed gamma dose rate in air due to the naturally occurring radionuclides as 1627.5 nGy h–1. A positive correlation has been found between U concentration and radon exhalation rate in the sand samples. The use of sand as construction material may pose a radiation risk to ambient environment.A K Mahur1*, Rajesh Kumar1, D Sengupta2 and Rajendra Prasad1 1Department of Applied Physics, Z. H. College of Engineering & Technology, Aligarh Muslim University, Aligarh-202 002, Uttar Pradesh, India 2Department of Geology and Geophysics, Indian Institute of Technology, Kharaghpur-721 302, West Bengal, India E-mail : [email protected] of Applied Physics, Z. H. College of Engineering & Technology, Aligarh Muslim University, Aligarh-202 002, Uttar Pradesh, India Department of Geology and Geophysics, Indian Institute of Technology, Kharaghpur-721 302, West Bengal, Indi

Measurement of radon activity, exhalation rate and radiation doses in fly ash samples from NTPC Dadri, India

520-523Radon activities and radon exhalation rates have been measured in fly ash samples from NTPC (National Thermal Power Corporation), Dadri situated in Uttar Pradesh, using “Can technique”. This technique employs LR-115 type II solid state nuclear track detectors fixed at the top of the “Can” filled with fly ash samples. Radon activity has been found to vary from (222.56 ± 25.8) to (673.68 ± 45.1) Bqm-3 with an average value of (431.71 ± 35.5) Bqm-3. Surface exhalation rate has been found to vary from (80 ± 9) to (243 ± 16) mBqm-2h-1 with an average value (155 ± 13) mBqm-2 h-1, whereas mass exhalation rate has been found to vary from (3.1 ± 0.4) to (9.34 ± 0.6) mBq kg-1h-1 with an average value of (5.98 ± 0.5) mBqkg-1h-1. Indoor inhalation exposure (radon) effective dose has also been estimated which is found to vary from (5.8 ± 0.7) to (17.6 ± 1.2) Svy-1 with an average value of (11.3 ± 0.9) Svy-1

Evaluation and analysis of ²²⁶Ra, ²³²Th, ⁴⁰K and radon exhalation rate in various grey cements

473-477The natural terrestrial gamma radiation dose rate is an important contribution to the average dose rate received by the world’s population. Natural radio nuclides in building material are sources of external and internal radiation exposure in dwellings. The natural radioactivity and radon exhalation rate of the commonly used building construction material (grey cements) have been studied. Positive correlation was found between radium concentration and radon concentration. The external radiation exposure caused by gamma emitting radionuclide is determined from obtained values of 226Ra, 232Th and 40K, using high purity Germanium Detector. The absorbed dose is found to be higher in the AMB cement. This study presents the results of estimation of 226Ra, 232Th and 40K concentration, gamma absorbed dose rates and radon exhalation rates of grey cements collected from different manufacturers

Radon levels in some dwellings around the international monument Taj Mahal, Agra using SSNTDs

802-804The Taj Mahal, Agra had been on top priority of India and safe guarded by Taj Mahal Corridor. All the gaseous industrial discharges as well as fluid chemicals and water due to rain and river Yamuna toxic polluting entities had been taken into account while maintaining the beauty of Taj and purity of environment around it’s rural areas. Indoor radon concentration depends in a complex way on the characteristic of the soil, the type of building structure, ventilation condition and occupant’s behaviour. LR-115 Type II Solid State Nuclear Track Detectors (SSNTD’s) have been used to measure the airborne radon levels in some dwellings near Taj Mahal, Agra. Radon concentrations were found to vary from 98 to 305 Bqm−3 with an average value of 213 Bqm−3. Annual effective dose in these dwellings were found to vary from 1.3 to 4.4 mSv

<smarttagtype namespaceuri="urn:schemas-microsoft-com:office:smarttags" name="country-region"><smarttagtype namespaceuri="urn:schemas-microsoft-com:office:smarttags" name="place"><smarttagtype namespaceuri="urn:schemas-microsoft-com:office:smarttags" name="City"> Study of radon exhalation rate and natural radioactivity in soil samples collected from East Singhbhum Shear Zone in Jaduguda U-Mines Area, Jharkhand, India and its radiological implications </smarttagtype></smarttagtype></smarttagtype>

486-492 In the present study, Sealed Can Technique was adopted for radon exhalation measurements in soil samples collected from some areas around the East Singhbhum shear zone in U-mining area of Jharkhand state of India. Radon activity varies from 3794.3 to 4891.4 Bqm-3 with an average value of 4368.6 Bqm-3 while radon exhalation rate varies from 1364.1 to 1758.6 mBqm-2h-1 with an average value of 1573.8 mBqm-2h-1. Activity concentrations of naturally occurring radionuclides (238U, 232Th and 40K) were also measured in these soil samples using high resolution γ-ray spectroscopic system. Activity concentrations were found to vary from 6.1 ± 0.2 to 826.3 ± 8.5 Bq kg-1 for 238U, 8.7 ± 0.3 to 236.7 ± 3.2 Bq kg-1 for 232Th and 291.5 ± 4.4 to 1391 ± 14.3 Bq kg-1 for 40K. From the activity concentration of 238U, 232Th and 40K in these soil samples, the radium equivalent activity (Raeq) due to the presence of radionuclides is calculated and it varies from 34.0 to 924.5 Bq kg-1 with an average value of 260.4 Bq kg-1. Total absorbed gamma dose rates in the surrounding air are found to vary from 15.1 to 402.0 nGyh-1 with an average value of 120.8 nGyh-1. The indoor and outdoor annual effective dose rates from these soil samples are determined from 0.1 to 1.9 mSv y-1 and 0.03 to 0.8 mSv y-1, respectively. External hazard index, Hex for the soil samples studied in this work ranges from 0.14 to 2.46 with a mean value of 0.70. The internal exposure to 222Rn and its radioactive progeny are controlled by the internal hazard index Hin. Computed values of Hin vary from 0.2 to 4.8 with an average value of 1.02. </smarttagtype