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.

Context: In Kudankulam, the South Eastern tip of India, a nuclear power station is under construction. Various studies have been carried out around this project site; however, there is no literature pertaining to the minerals in cow milk samples in this region. Further, various minerals in cow milk are analogs of natural and anthropogenic radionuclides and a study on stable elements would help to assess the behavior of their radioactive counterparts. Materials and Methods: Milk samples (n = 25) from the study area were analyzed for macro-minerals (potassium [K], magnesium [Mg] and calcium [Ca]) and micro-minerals (zinc [Zn], copper [Cu] and manganese [Mn]) using a Z5000 series Hitachi atomic absorption spectrophotometer. The performance of the method was evaluated by using an International Atomic Energy Agency (IAEA) reference material, i.e., the fish tissue homogenate (IAEA-407). Results: The concentration values of major and trace minerals in the milk samples were in the order Ca > K > Mg and Zn > Cu > Mn, respectively. Conclusion: The high-water Ca levels and the prevailing tropical semi-arid climatic conditions seem to be the reasons for the high-Ca levels observed in the investigated milk samples. A CaCO3 bed is present in this area and lime is being excavated by cement industries and it is also evident from the literature that elevated Ca levels would have an immense impact on the levels of natural and fall out radionuclides in cow milk.

Context: The paper describes about the experience gained during the radiation monitoring of inactive scrap generated at various nuclear facilities. This type surveillance is carried out to prevent the spread of radioactivity in public domain and also as requirement by regulatory authorities. Aim: The inspection and certification of scrap material from Nuclear facilities is a regulatory requirement to ensure that no radioactive material reaches public domain. This paper describes the methodology and experience in detection of radioactivity at inactive Scrap monitoring facility. Materials and Methods: Inactive scraps (metallic and non metallic) generated from various nuclear facilities of BARC, Trombay is dispatched to Trombay Village Store (TVS) for temporary storage before auction to the public. The monitoring at the facility includes visual inspection and radiation measurement before loading the scrap in the truck. An online PC based monitoring system and portable monitoring instruments in the range (nSv/h-μSv/h) are used to carry out radiation monitoring of inactive scrap loaded in a vehicle. Results: Radioactive source of high activity with potential for serious environmental hazard has not been detected, but few cases of presence of radioactive /contaminated material (MS plate/equipments with low level of Cs-137 contamination) have been detected and identified using portable gamma spectrometer. Conclusion: Implementation of strict regulatory measures and radiation monitoring at nuclear facilities can minimize the probability of radioactive material reaching the public domain. The methodology followed for monitoring of inactive scrap is found to be effective even for detection of presence of radioactivity in scrap if any.

Background: All objects in nature are exposed to ionizing radiation emitted by primordial radionuclides and cosmogenic radionuclides due to cosmic rays, the influence of which on living beings is very imminent and important to study. The amount of this background radiation received by an individual depends on altitude, latitude type of building and the building construction materials. Materials and Methods: In the present study, measurements of natural background radiation were made in the schools, temples, dwellings, and hill stations etc., in Chamaraja Nagar District, Karnataka State, India by using Environmental Dosimeter technique. Results and Conclusion: The absorbed dose rate in dwellings of different villages in this region varies from 98.3 ± 7.1 to 708.2 ± 59.3 nGyh⁻¹ with an average of 291.8 ± 23.4 nGyh⁻¹ , whereas in temples it varies from 71.4 ± 5.2 to 589.0 ± 46.3 nGyh⁻¹ with an average of 240.5 ± 19.2 nGyh⁻¹ .

Introduction: Internal exposure monitoring for alpha emitting radionuclides is carried out by bioassay samples analysis. For occupational radiation workers who handle uranium in reprocessing or fuel fabrication facilities, there exist a possibility of internal exposure and urine assay is the preferred method for monitoring such exposure. Materials and Methods: Separation of Uranium is carried out by extraction chromatography using diamyl amyl phosphonate (U/TEVA) resin. This resin contains diamyl amyl phosphonate extractant supported on inert Amberlite XAD-7 (an acrylic ester) resin.The electrodeposited samples are counted using octet alpha spectrometery. Results and Discussion: The analysis time involved from sample loading to stripping is 2 h compared with the 3.5 h involved in conventional ion exchange method. The radiochemical yield was found in the range of 69-91%. Minimum detectable activity for uranium estimation for 3,60,000 s counting time at an average percentage recovery of 82 ΁ 8 works out to 0.21 mBq/d. Conclusion: The technique gives good and consistent radiochemical yield of 82% on repeated use of the chromatographic column when compared with ion exchange technique. Analysis time involved from sample loading to stripping using UTEVA is 2 h compared with the time involved of 3.5 h by the conventional ion exchange method.

Context: ¹³¹ I is widely used for diagnostic and therapeutic purposes. Since thyroid is the main deposition site for ¹³¹ I, so it can be detected by direct thyroid monitoring. Aim: This work presents results of follow-up measurements of an individual who was internally contaminated with ¹³¹ I with injected activity being determined by maximum likelihood method. Importance of dose per unit content is also shown in this study. Materials and Methods: The whole body monitoring system available in Radiation Safety Systems Division of Bhabha Atomic Research Centre is calibrated for estimation of ¹³¹ I in the thyroid of radiation worker using BOttle MAnnikin Absorber (BOMAB) phantom with neck part being replaced by American National Standards Institute (ANSI)/International Atomic Energy Agency (IAEA) neck. Results: The estimated intake was found to be 89.24 kBq and the committed effective dose is calculated as 1.96 mSv. The data are analyzed with autocorrelation and Chi-square test to establish goodness of fit with log-normal distribution. Conclusion: The overestimation of thyroid activity by use of mid axial hole in BOMAB phantom is removed by using ANSI/IAEA neck phantom. Measured retained thyroidal data on different days following the intake has closely fitted to the ICRP predicted retained activity.

Background: The potential hazard of radiation exposures to radon and its daughter products from natural background has been highlighted in the world of scientific press and has become a matter of concern. The Lake Bosumtwi is one of the interesting research areas in Ghana due to the geological nature of the area, and also of its great importance based on the different uses of the lake and its surroundings. There is therefore the need to investigate the levels of radon activity in soil samples around Lake Bosomtwi basin as part of the national effort to establish base line data of radon levels in Ghana. Materials and Methods: The study was conducted to measure the levels of radon activity in soil samples within the lake Bosomtwi basin. Samples were collected from five selected villages around the lake at depths of 10 cm and 20 cm. The Role's Method was employed and measurements were made using specific cell counters. The measurements were performed with a Radon Degassing Unit (RDU-200) and a Radon Detector Analyzer (RDA-200). The calculated cell efficiency was obtained as 0.55 cpm/dpm. Results: The average radon concentrations at the depths were calculated and the maximum concentration for the 10 cm depth was obtained from Tepaso with a value of 4801.71±678 Bq/m ³ and the minimum concentration was obtained from Abonu with a value of 3887.07±815 Bq/m ³ . The maximum and minimum concentrations for the 20 cm depth were obtained from Tepaso and Kusuasi with values of 5602.10±943 Bq/m ³ and 4877.93±404 Bq/m ³ respectively. The overall average radon concentration obtained was 4745.31±559 Bq/m ³ . The results obtained were high when compared with results from previous studies. The values obtained are less than the World Health Organization's acceptable level for outdoor radon activity which is quoted as 9250 Bq/m ³ and hence the public are not exposed to any significant radiological health hazard in these areas. Conclusions: The radon concentration at the depth of 20 cm was found to be higher than the 10 cm depth and this shows that radon gas in soil increases with depth. The values obtained are less than the World Health Organization's acceptable level for outdoor radon activity and life activities would not be at risk in these areas.

Background: Since the Madras Atomic Power Station, Kalpakkam and Kudankulam Nuclear Power Plant, Kudankulam are sited in Bay of Bengal coast, radiological study of this coastal environment is imperative to assess the impact of operation of nuclear power plant, if any, on the radioactivity profile of the coast. Materials and Methods: In the present study the environmental radioactivity was evaluated by measuring activity concentrations of primordial radionuclides namely ²³⁸ U, ²³² Th and ⁴⁰ K. in the beach sand samples using high purity germanium gamma ray spectrometry. 10 sampling stations were fixed along a 290 km coastal stretch of Bay of Bengal from Pondycherry to Velangannni. Results: The activity concentration of ²³⁸ U is always much less than that of ²³² Th and ⁴⁰ K and it ranged from 9 Bq/kg (Pondicherry coast) to 93 Bq/kg (Karaikal coast). However, ²³² Th concentration fluctuated from 12 Bq/kg (Pichavaram Mangrove) to 1075 Bq/kg (Karaikal coast). The activity concentration of ⁴⁰ K varied within a narrow range from 162 Bq/kg to 474 Bq/kg. The distribution of primordial radioactivity was non-uniform along the entire stretch of Bay of Bengal. The elevated levels of ²³² Th were recorded in Karaikal coast (S7) (1075 Bq/kg), Tirumullaivasal coast (S4) (215 Bq/kg), and Nagapattinam coast (S9) (146 Bq/kg) and attributed to the presence of thorium-rich monazite as beach placer in coastal sands. Conclusion: The total absorbed gamma dose contributed by the activity of ²³⁸ U, ²³² Th, and ⁴⁰ K varied between 29 nGy/h and 308 nGy/h with a GM value of 64.4 nGy/h. Similarly, the annual effective dose recorded for Bay of Bengal ranged from 0.04 mSv/year to 0.38 mSv/year, indicating that the Bay of Bengal, in general, falls under Normal Background Radiation Area.

Phoswich detector with its pulse shape discrimination (PSD) electronics is being used for estimating actinides in lung as part of in vivo monitoring. In this application, only the signals from thin NaI (low energy measurement) are effectively utilized. The high-energy gamma interactions in thick CsI portion of phoswich are merely used for background reduction in the low-energy regions. The present PSD electronics was suitably modified; both lower and higher energy photon spectra from a single phoswich detector are recorded simultaneously. This feature helps in identifying any fission product gamma emitters and also detects the increase in background during lung counting measurements. This paper outlines the modifications incorporated in the PSD electronics and the suitability of phoswich detector as a gamma ray spectrometer. The typical spectrometric characteristics of the detector such as energy linearity, full width at half-maximum, point source efficiency, and so on, estimated through experiments, and some of the salient results are highlighted.