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Radiation safety issues relevant to proton therapy and radioisotope production medical cyclotrons
Bhaskar Mukherjee
July-December 2012, 35(3):126-134
Medical cyclotrons are now constructed as turnkey facilities at nuclear medicine clinics, specialised particle therapy facilities and radioisotope production centres. Most medical cyclotrons usually accelerate protons to high energies and could be divided mainly in two categories: (a) Low energy (E P = 15-30 MeV) machines, dedicated for medical positron emission tomography and single photon emission computer tomography radioisotope production and (b) High energy (E P = 100-250 MeV) machines, predominantly used for radiotherapy of malignant tumours. Parasitic gamma and neutron radiation are produced during the operation of medical cyclotrons. Furthermore, high level of gamma radiation produced by the activated cyclotron components could impose radiation exposure to maintenance crew. Hence, radiation safety is imperative to safe and reliable operation of medical cyclotron facilities. A sound operational health physics procedure assures the minimisation of radiation exposure to patients and members of the public abiding the regulatory guidelines. This paper highlights the important radiation safety aspects related to safe operation of proton therapy and radioisotope production medical cyclotrons.
  7,243 1,133 1
Thermoluminescence, optically stimulated luminescence and radiophotoluminescence dosimetry: An overall perspective
Bhuwan C Bhatt
January-March 2011, 34(1):6-16
Radiation dosimetric methods are used for the estimation of dose absorbed by radiation in a detector material. These methods are required for estimation of absorbed dose in various applications of radiation, such as personnel and environmental dosimetry, retrospective/ accident dosimetry and medical applications of radiation. The use of thermoluminescence (TL) as a method for radiation dosimetry of ionizing radiation has been established for many decades and has found many useful applications in various fields, such as personnel and environmental monitoring, medical dosimetry, archaeological and geological dating, space dosimetry. Several high sensitivity TL phosphor materials and thermoluminescent dosimeters (TLDs) are now commercially available in different physical forms. There are many commercial TLD systems which are being used for various dosimetric applications and even presently, TL is a major player in the field of radiation dosimetry, particularly in personnel dosimetry. In the last two decades an alternative technique, optically stimulated luminescence (OSL), has been developed, as the optical nature of the readout process does not involve problems of blackbody radiation and thermal quenching. Due to this and some other advantages OSL is also being used for various applications in radiation dosimetry, such as personnel and environmental dosimetry, retrospective/ accident dosimetry and medical dosimetry. The development of Al 2 O 3 :C TL/OSL phosphor by Akselrod et al. and later investigation of its suitability for personnel dosimetry using pulsed OSL (POSL) technique of stimulation by Akselrod and McKeever, resulted in the development of a personnel dosimetry system based on Al 2 O 3 :C OSL phosphor. Therefore, thrust of modern luminescence dosimetry development is more towards OSL. The main advantages of the small size optic fiber based OSL dosimeter over the currently available radiation detectors, such as TLD, used in clinical applications, are the capabilities of measuring both real-time dose rate (using radioluminescence, RL) and absorbed dose (using OSL). Although radiophotoluminscence (RPL) dosimeters were developed in parallel with TLD systems during 1960s, but high pre-dose and photon energy dependent detector material prevented major breakthrough of the glass dosimetry. Therefore, RPL glass dosimeters were used as an emergency dosimeter in accident situations. However, in mid 1980s introduction readout systems using a pulsed UV stimulation, in place of conventional mercury UV lamps, helped in reducing pre-dose by a factor of 100 (from mSv to a few μSv). Use of pulsed stimulation permits electronic discrimination of the signals from the pre-dose and absorbed dose on account of their different fluorescence decay times. This development resulted in the manufacture of improved RPL glass dosimeters and fully automatic RPL reader systems capable of measuring doses in the range 10μSv to 10Sv. In 2001, silver activated phosphate RPL glass dosimetry system has been introduced as the major personnel monitoring service in Japan marketed by Chiyoda Technol Corporation. Some of these developments in the field of TL, OSL and RPL dosimetry are reviewed.
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Design of prototype two element optically stimulated luminescence dosimeter badge for eye lens monitoring
MS Kulkarni, Munish Kumar, P Ratna, KP Muthe, K Biju, C Sunil, D. A. R Babu, DN Sharma
April-June 2014, 37(2):106-111
A prototype two element eye lens dosimeter badge based on highly sensitive α-Al 2 O 3 :C optically stimulated luminescence dosimeters (OSLDs) was designed and developed. The badge consists of a plastic card in which two thin α-Al 2 O 3 :C optically stimulated luminescence (OSL) discs are placed. The OSLDs in the plastic card (when inserted into plastic cassette) are covered with energy compensation filters made up of 0.3 mm thick Cu and 1.35 mm thick Teflon discs positioned symmetrically on both sides of the dosimeter. The OSLD badge is useful for monitoring doses from photons and beta particles. In this paper, theoretical studies using Monte Carlo method as well as using the analytical technique have been performed to study the energy response of the bare α-Al 2 O 3 :C based disc dosimeters. These dosimeter discs have been found to exhibit over-response by a factor of ~ 3.4 at ~ 33 keV photon energy, whereas, beyond 80 keV photon energy, the response is nearly energy independent. Studies have also been performed to find the energy response of the α-Al 2 O 3 :C disc dosimeters under different metal filters, viz., Al, Cu, Sn etc., and under various thicknesses of Teflon. From theoretical simulations, it has been found that 0.3 mm thick Cu is sufficient to correct the over-response in lower energy region within acceptable limits. Further, Teflon disc (DuPont, USA) having thickness of 1.35 mm is found to be the optimized choice as filter for the second dosimeter disc. It is worth mentioning that the ratio of the response of the OSL disc under Teflon to that under Cu filter indicates average energy of X-ray photons and same is used to correct the over-response as well as to estimate the quantity H p (3). Also for higher photon energy region, the readout of the dosimeter disc under Teflon filter directly measures the quantity H p (3). Same holds true for beta particles having maximum beta energy, Emax beyond 0.7 MeV.
  4,807 1,012 -
Effect of gamma irradiation on germination, growth, and biochemical parameters of Terminalia arjuna Roxb
Akshatha , KR Chandrashekar, HM Somashekarappa, J Souframanien
January-March 2013, 36(1):38-44
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.
  4,754 792 11
Antioxidant, antibacterial, and ultraviolet-protective properties of carotenoids isolated from Micrococcus spp.
Devihalli Chikkaiah Mohana, Sreerangegowda Thippeswamy, Rayasandra Umesh Abhishek
October-December 2013, 36(4):168-174
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.
  4,876 576 4
Prospective survey of accelerator safety
PK Sarkar
July-December 2012, 35(3):103-104
  1,745 3,060 -
Radiological protection aspects of natural radioactivity of building materials
October-December 2011, 34(4):220-220
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Radiological safety aspects of an accelerator driven system
C Sunil
July-December 2012, 35(3):145-155
Accelerator driven systems (ADS) have the potential to generate nuclear power by coupling a high energy high current proton accelerator to a sub-critical nuclear reactor. The system has several advantages such as inherent safety from a runaway chain reaction, independence of the reactivity from delayed neutrons, resistance to nuclear proliferation, ability to transmute long lived minor actinides and fission products and, to convert thorium to 233 U. The radiological safety aspects of a typical ADS are discussed in which lead bismuth eutectic (LBE) is the spallation target as well as the coolant. In the irradiated target, residual activity is a major concern, particularly the amount of 210 Po. The time evolution of the major isotopes present in LBE is studied along with the prevailing residual gamma dose rates. Few issues that may surface while coupling a reactor to an accelerator are also discussed.
  3,454 282 -
Origin of thorium deposits in Kerala beach sands
MR Iyer
July-September 2015, 38(3):98-101
The origin of the thorium deposits on the West Coast of India is not well established though a number of studies on the various aspects of these deposits have been carried out for more than 50 years. The deposits are believed to be washed down from highlands through water streams. It is proposed that atom ratios of various radioactive and stable products in the uranium and thorium series as a function of time could be effectively used for the purpose. Accordingly, the various ratios have been calculated as a function of the age in the time range of 100-70,000 years. The stable products are included for the first time.Pb-208/Th-232 in Th-232 series, Pb-207/U-235, Pb-207/Pa-231, and in U-235 series and Pb-206/U-238, Pb-206/U-234, Pb-206/Th-230, and Pb206/Ra226 in U-238 series, are presented. The ratios show significant variations in the time range studied. The ratio Pb-206/Pb-207 from the two uranium series is of interest and is examined. This ratio shows a variation of up to 100 times whereas, the natural isotopic ratio is around unity. It is suggested that an extensive measurement of these ratios and their correlation in samples from the hypothesized source in highlands, in river beds, and on the beach sand might give some idea of the transport path for these minerals. Further, it is suggested to measure the ratio of all the lead isotopes from the three series with Pb-204 which is purely of primordial in origin which would also be useful to indicate the contribution from radiogenic sources. In order to undertake such a project which, of course, involves many disciplines large efforts in sampling, in modeling of possible transport paths and strategies for analysis are required.
  3,526 168 -
NDMA guidelines on management of nuclear and radiological emergencies
MC Abani
January-March 2011, 34(1):17-22
The National Disaster Management Authority (NDMA), ever since it's formation as an apex policy making body for the country in the field of disaster management, has formulated a set of guidelines to assist the various ministries, states and stakeholders in preparing their plans to handle different types of disasters. The guidelines on management of nuclear and radiological emergencies assume great importance in the present context, as our country has very ambitious programme to exploit nuclear energy for peaceful uses. Though, we have an enviable and impeccable record of safety and virtually fail-safe operations in all our nuclear establishments, the possibility, however, remote it may be, of human error, systems failure, sabotage, earthquake, floods, terrorist attacks etc leading to the release of radioactive material in the public domain, cannot be entirely ruled out. With this view, it was decided to prepare the national guidelines by NDMA to manage any nuclear/radiological emergency in public domain. Through these guidelines, we aim to further strengthen our existing nuclear/radiological emergency management framework and generate public awareness, which will go a long way in allaying misapprehensions, if any, amongst the public about the country's nuclear programme. Like in all our guidelines for handling of different types of the disasters, in these Guidelines also, maximum emphasis has been laid on the prevention of nuclear and radiological emergencies, along with a detailed consideration of all other elements of the disaster management continuum. The National guidelines have been prepared and a consensus was arrived on various issues, after wide-spread consultations and elaborates discussions amongst experts as well as stakeholders. It is assumed that once these guidelines are implemented by the stakeholders and converted into action plans followed by SOPs that will further reduce the chances of accidents in the nuclear arena.
  3,235 402 -
Analysis of neutron streaming through the trenches at linac based neutron generator facility, IGCAR
Usha Pujala, L Thilagam, TS Selvakumaran, DK Mohapatra, E Alagu Raja, KV Subbaiah, R Baskaran
October-December 2011, 34(4):262-266
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.
  3,251 364 4
Radioactivity in human body and its detection
DD Rao
April-June 2012, 35(2):57-58
  3,082 437 -
Residential radon exposure in some areas of Bangalore city, India
GV Ashok, N Nagaiah, NG Shiva Prasad, MR Ambika, LA Sathish, N Karunakara
April-June 2012, 35(2):59-63
Background: Two isotopes, 222 Rn and 220 Rn of the natural radioactive gas radon are generally of radiological importance. About half of the total radiation effective dose to the general public is due to the irradiation of the lungs by alpha particles following the inhalation of radon decay products. In view of this, 222 Rn and 220 Rn measurements were carried out for a period of 1 year in about 50 dwellings belonging to different residential areas of Bangalore city. The results obtained were systematically analysed and discussed. Materials and Methods: 222 Rn and 220 Rn measurements were carried using Solid State Nuclear Track Detectors. The gamma exposure rate measurements were also carried out in all the dwellings using a G M tube based Environmental Radiation Dosimeter. Results: The concentration of 222 Rn and 220 Rn was found to be highest in the dwellings having mud flooring (Bare) and lowest in the dwellings having mosaic flooring. The geometric mean values of the concentrations of 222 Rn and 220 Rn were found to be 24.1 ± 8.3 and 24.5 ± 10.8 Bq m -3 respectively. The annual mean value of the gamma absorbed dose rate is found to be 175.8 nGy y -1 . Conclusion: The mean value of radon concentration is well within the indian average (42 Bq m -3 ) and world average (40 Bq m -3 ) values. The mean effective dose was found to be 1.19 mSv y -1 and is well within the action level as prescribed by ICRP-65.
  3,036 331 -
Threshold limit values and their applicability in the realms of chemical exposure control
S Soundararajan
January-March 2011, 34(1):77-80
Chemicals are useful and indispensable in every walk of our life. Nuclear industry is no exception to this fact. A number of chemicals are in use in the nuclear fuel cycle. Thus, hazards due to exposure to chemicals coexist with radiological hazards in a nuclear fuel cycle industrial or research set-up. In the realms of control of chemical exposure, limits on concentration of chemicals in workplace are prescribed. These are known as occupational exposure limits. Threshold Limit Value (TLV) is one such occupational exposure limit. American Conference of Governmental Industrial Hygienists (ACGIH) prescribes TLVs as guideline values for various chemicals and also for physical agents. The discussion is confined to philosophy of chemical TLV, its applicability, and its limitations.
  3,102 240 -
Radiation safety for electron accelerators: Synchrotron radiation facility
Yoshihiro Asano
July-December 2012, 35(3):135-144
Radiation safety is reviewed for electron accelerators, mainly synchrotron radiation facilities. Accelerator radiation safety systems consist on safety interlock system, radiation shielding and radiation monitoring. These systems depend strongly on the characteristics of machines such as the maximum electron energy. In this paper, conceptual safety systems and radiation sources for synchrotron radiation facilities are overviewed including the evaluation methods of shielding.
  2,898 421 2
Overview of experimental works on secondary particle production and transport by high-energy particle beams
Takashi Nakamura
July-December 2012, 35(3):111-125
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.
  2,764 395 2
Thermoluminescence and photoluminescence study of CaSO4 : Dy nanophosphor for 6 MeV energy electron dosimetry
Nandkumar T Mandlik, Vasant N Bhoraskar, Puroshottam D Sahare, Bhushankumar J Patil, Vipin Kumar, Mukund S Kulkarni, Sanjay D Dhole
July-September 2011, 34(3):185-189
Nanoparticles of CaSO 4 : Dy with size around 25 nm, were synthesized by the chemical co-precipitation method for the purpose of high energy electron dosimetry. The nanocrytstalline samples were irradiated with 6 MeV energy electrons having fluence varied from 3 × 10 14 to 2 × 10 15 e/cm 2 .The pre and post irradiated samples were characterized by the XRD, SEM, PL and TL techniques. The XRD spectra show the orthorhombic phase and do not change with the electron fluence. Moreover, the particle size found to be around 25 nm and marginally increased from 25 nm to 34 nm with the increase in the electron fluence. SEM image confirms the existence of the nanoparticle around 30 to 40 nm. In PL emission spectra, a shift towards lower wavelength has been observed with decrease in particle size from micrometer to nanometer. This mainly attributes to the extension in the band gap of Dy 3+ ions. The TL spectra exhibit four peaks at around 437,545,638, and 748 K respectively. The TL response curve shows that the peak intensity initially increased with electron fluence, and at a fluence of 9 × 10 14 e/cm 2 saturates then decreased with increase in the electron fluence. It is mainly due to the generation of different kinds of trapping centers. The present study indicates that the CaSO 4 : Dy phosphor can be used for the measurement of dose of 6 MeV energy electrons over a range varying from 1 kGy to 25 kGy.
  2,550 372 1
Geological significance of radon gas in soil and underground water: A case study of Nurpur area, District Kangra, Himachal Pradesh, India
Dinesh Kumar Sharma, Ajay Kumar, Arvind Kumar, Sunil Dhar, Surinder Singh
January-March 2013, 36(1):3-9
Remote sensing satellite data have been used to recognize structures having tectonic significance. Based on satellite data, lineament map of Nurpur and its adjoining area of District Kangra, Himachal Pradesh, has been generated. LR-115 solid state nuclear track detectors have been used for the measurement of soil gas radon at 71 different locations of the study area. Radon monitoring in underground water at 26 different locations of the study area has been carried by scintillometry. The results indicate zones of lineament density and tectonically induced radon in soil and underground water. The results are co-relatable with regional geology of the area.
  2,635 272 -
Studies on radon concentration in aqueous samples at Mysore city, India
BM Rajesh, MS Chandrashekara, P Nagaraja, L Paramesh
January-March 2012, 35(1):9-13
Context: Natural radionuclides are wide spread in air, water, soil, plants and in consequence in the human diet. 222 Ra is the daughter product of 226 Ra which belongs to 238 U radioactive series. Aims: Radon enters the human body through ingestion of water and inhalation. Since alpha emitters are the most dangerous, studies on water containing dissolved radon are very important. Materials and Methods: The activity concentration of 222 Ra has been analyzed in water samples collected from lakes, open wells, drilled wells, taps and rivers in and around Mysore city, Karnataka State, India using radon emanometric technique. Results: The present study shows a wide range of radon concentration in water, which varies from below detection limit to 643.9 BqL -1 with a median of 15.8 BqL -1. An annual effective dose with a median of 0.043 μSv y-1 was estimated from the ingestion of 222 Ra through water. Conclusions: 222 Rn concentration in 80% of bore-well water samples are higher than the maximum acceptable contaminant level of 11.1 BqL -1 as prescribed by the environmental protection agency.
  2,340 429 -
Networked national occupational dose registry system
SS Sanaye, RH Meena, Sujatha Baburajan, SG Pawar, BK Sapra, YS Mayya
October-December 2010, 33(4):167-170
Monitoring of radiation workers and maintaining their dose data is an important part of radiological protection program. As per RPR-71 (and presently RPR-2004), it is a regulatory requirement. National Occupational Dose Registry System (NODRS) at Bhabha Atomic Research Centre (B.A.R.C.) is maintaining and updating annual and lifetime dose data of all monitored radiation workers since the inception of Directorate of Radiation Protection in late sixties. The registry has a database of over 4,00,000 radiation workers. Over the years, the registry underwent several structural, software and hardware changes. Recently, it has been upgraded to network all monitoring labs located at NPP sites and other DAE units with the main database server at BARC through NPCNET and ANUNET. The new system provides online information on dose data, previous dose history of radiation worker which is an important requirement for monitoring units. Capability of NODRS to store biometric information of radiation workers enhances the effectiveness of the system. This paper gives the outline of NODRS along with some analysis of the data accumulated over the years.
  2,351 365 -
Fukushima to Jaitapur: Battling fear of unknown
Tushar P Ghate, MG Takwale, Sanjay Dhole
July-September 2011, 34(3):159-163
After-Fukushima incident, various concerns were raised by public and media about the safety of nuclear installations operating all around the world. All nuclear related eventualities of the past were meshed with the present, adding disproportionate factors, unrealistic conclusions were framed based mostly on notions. Fear of unknown radiation syndrome has played up on the minds of common man. India, on a verge of entering path-breaking nuclear energy arena, obviously could not be isolated from such concerns. Such issues were discussed with ongoing protests at Jaitapur and Kudankulam. This paper discusses various concerns expressed after Fukushima incident, overview on proposed Jaitapur nuclear power plant and justifications to the raised concerns.
  2,435 273 1
Measurements of radon concentrations in ground water samples of tectonically active areas of Himachal Pradesh, North West Himalayas, India
Vishal Arora, Bikramjit Singh Bajwa, Surinder Singh
January-March 2011, 34(1):50-54
The paper discusses the result of systematic measurement of activity concentration of radon in ground water samples of seismically active areas of N-W Himalayas, Himachal Pradesh, India. Himalayan region is being subjected to intense neotectonic movements and seismic activities. For systematic study, the study area has been divided into three Zones on the basis of lithology and thrust systems of the area viz. Zone-I, Zone-II and Zone-III. Water radon concentrations were measured using RAD-7 equipped with an appropriate unit (Aqua kit) following a protocol proposed by the manufacturer. Water samples have been collected from the different sources and wide range of the villages from the Zone-I, II and III respectively. The radon concentration in water samples collected from Zone-I has been found to be varying from 8.4Bq/l to 314Bq/l with average value 61.2 Bq/l. The radon concentration in water samples collected from Zone-II has been found to be varying from 14.4Bq/l to 140Bq/l with average value 50.8 Bq/l. The radon concentration in water samples collected from Zone-III has been found to be varying from 9.3Bq/l to 77.8Bq/l with average value 23.2 Bq/l.
  2,308 370 -
Measurement of natural activities of 238 U, 232 th and 40 k in tin ore
Nassif A Mansour
October-December 2011, 34(4):270-274
Tin ore is widely used in many industrial purposes. Such as tin ore contain natural radioactive nuclides at various concentrations. If this ore contain high concentrations of natural radioactive nuclides, workers handling them might be exposed to significant levels of radiation. Therefore it is important to determine the radioactive nuclides in this ore. The natural radionuclides ( 238 U, 232 Th and 40 K) and their daughter products contents of tin ore have been estimated in gamma-ray spectrometry and their levels using 70% Hyper-Pure` Germanium (HPGe) detector. The mean activities due to the three radionuclides ( 238 U, 232 Th and 40 K) were found to be 40 ± 3, 19 ± 2.2 and 97 ± 19 Bqkg−1 , respectively. The radium equivalent activity varied from 77.87 ± 11-12.03 ± .27 Bqkg−1 . The representative external hazard index values for the corresponding Tin Ore are also estimated. The results of this assessment obtained by the gamma-ray spectroscopic analysis, have indicated that the levels of natural radioactivity were lower than the international recommended limits.
  2,327 290 -
Effect of impregnating materials in activated carbon on Iodine -131 ( 131 I) removal efficiency
Maghsoud Gourani, Asghar Sadighzadeh, Farhang Mizani
July-September 2014, 37(3):179-183
Activated carbon (AC) is widely used in various industries as an adsorbent material. It is used in gas cleaning industries, because of its low cost and high efficiency for removal of pollutants from effluents. It can be produced from a wide range of agricultural activities as by-products. There are different methods for producing the AC. The most common methods are physical and chemical activation that includes heat treatment, amination and impregnation. In this study, the effect of three impregnates, i.e., NaOH, KI and ZnCl 2 on the quality of AC for 131 I removal, was investigated. Our results show that the sodium hydroxide impregnated AC is more effective for 131 I removal. Also, the quality of the impregnated AC was decreased in the case of impregnants material percentage exceeding 2%wt.
  2,210 328 -
Analysis of radon concentration in drinking water in Hanumangarh district of Rajasthan, India
Vikas Duggal, Rohit Mehra, Asha Rani
April-June 2013, 36(2):65-70
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.
  2,143 328 4