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In continuation to our earlier studies concerning generation of the baseline indoor radon data, an indoor radon measurement survey was carried out in the districts Bagh and Kahuta, state of the Azad Jammu and Kashmir. In this context, 150 houses were selected in the aforesaid districts and CN-85-based box-type radon detectors installed in bedroom and living room of each house. The detectors were exposed to indoor radon for 3 months. After etching CN-85 detectors in 6 M NaOH at 70°C for 3 h, the observed track densities were related to the indoor radon concentration using calibration factor of 0.0092 tracks cm−2·h−1 per Bq·m−3. The measured indoor radon concentration ranged from 56 to 124 Bq·m−3 and 61 to 106 Bq·m−3 in the studied areas of districts Bagh and Kahuta, respectively. The mean annual effective dose ranged from 1.42 ± 0.15 to 3.12 ± 0.10 mSv·y−1 with an average of 2.16 ± 0.13 mSv·y−1 in the district Bagh and 1.54 ± 0.14 to 2.68 ± 0.12 mSv·y−1 with an average of 2.17 ± 0.13 mSv·y−1 in the district Kahuta. These values are within the safe limits recommended by the World Heath Organization. [ABSTRACT FROM AUTHOR]

Abstract: The radionuclide 125Sb is a long-lived fission product, which decays to 125Te by negative beta emission with a half-life of 1008 day. The beta decay is followed by the emission of several gamma radiations, ranging from low to medium energy, that can suitably be used for high-resolution detector calibrations, decay heat calculations and in many other applications. In this work, the beta decay of 125Sb has been studied in detail. The complete published experimental data of relative gamma ray intensities in the beta decay of the radionuclide 125Sb has been compiled. The consistency analysis was performed and discrepancies found at several gamma ray energies. Evaluation of the discrepant data was carried out using Normalized Residual and RAJEVAL methods. The decay scheme balance was carried out using beta branching ratios, internal conversion coefficients, populating and depopulating gamma transitions to 125Te levels. The work has resulted in the consistent conversion factor equal to 29.59(13) %, and determined a new evaluated set of the absolute gamma ray emission probabilities. The work has also shown 22.99% of the delayed intensity fraction as outgoing from the 58 d isomeric 144keV energy level and 77.01% of the prompt intensity fraction reaching to the ground state from the other excited states. The results are discussed and compared with previous evaluations. The present work includes additional experimental data sets which were not included in the previous evaluations. A new set of recommended relative and absolute gamma ray emission probabilities is presented. [Copyright &y& Elsevier]

This article reports the efficiency response curve of the high-purity germanium detector over the wide energy range, covering from 120 to 8500 keV. The efficiencies were measured for different counting geometries by using point radionuclide standards (mono-energetic as well as multi-gamma emitters) supplied by IAEA and the capture gamma-ray facility installed at PINSTECH nuclear reactor PARR-1. The measured efficiencies were required to fit with a suitable fitting function for interpolation within the energy range of interest. Several fitting functions were proposed in the literature covering different energy ranges. The functions giving the best fit to experimental data are presented. The work has successfully extended the response curve beyond 1500-8500 keV, which is the region where the standard calibration radionuclides are not available. The thermal neutron capture gamma-ray facility provided the collimated neutron beam, extracted from the core of the reactor and made to react with ammonium chloride target to produce the capture gamma rays for determining the efficiencies in the extended region. It was found that the capture gamma-ray provides a satisfactory solution to extend the absolute efficiency calibration in the MeV range. It was also found that the fitting function that is linear in its parameter was highly satisfactory up to 1500 keV but proved insufficient upto 8500 keV. The exponential function giving the good fit over the range has been presented. Good agreement has been found between the experimentally measured absolute efficiencies and the predicted result. [ABSTRACT FROM AUTHOR]

The prompt gamma neutron activation analysis (PGNAA) facility at the Pakistan Research Reactor (PARR-I) has been used for elemental analysis of different kinds of materials. A high-efficiency, high-resolution gamma spectrometer based on a high-purity germanium detector is being employed in this study. The cadmium ratio of the incident neutron beam is 62 and the thermal neutron flux at the target position is about 1.5 × 106 n/cm²/s. The system is usually operated in Compton suppression mode to enhance peak to background ratio in the lower energy region (< 1.5 MeV). The gamma ray detector is calibrated with standard radioactive sources up to 1.5 MeV. The aim of the present study is to determine the quantity of boron in reactor grade steels as well as in some other materials containing boron. The results of boron assessment in SS-304L and amorphous (Fe0.99Mo0.01)78Sid9B13 alloy are also presented. [ABSTRACT FROM AUTHOR]

Abstract: The natural radionuclides 210Pb and 7Be have been widely used as tracers of aerosols for the study of pollution and atmospheric transport processes. The depositional fluxes of atmospheric 210Pb and 7Be-bearing aerosols in precipitation samples have been continuously measured from October 2006 to April 2010 at a high altitude city of Murree (33° 85′ N, 73° 41′ E, Alt.2300m a.s.l) and low altitude city of Islamabad (33° 38′ N, 73° 09′ E, Alt. 534m a.s.l), Pakistan, using a high resolution spectrometer. The specific activity values of 210Pb and 7Be measured in rain samples collected monthly from open lawn of Murree ranged from 2–87 mBq l−1 and 80–1680mBql−1 with their mean values of 30±11mBql−1 and 573±201mBql−1, respectively. Similarly the mean specific concentration values of 210Pb and 7Be in open lawn rain samples of Islamabad are 123±12mBql−1 and 442±321mBql−1 respectively. The specific concentrations of 210Pb and 7Be in throughfall samples collected at Murree site only are in the range from 5–34mBql−1 and 110–1177mBql−1 with the mean values of 17±6mBql−1 and 442±321mBql−1 respectively. The annual deposition fluxes of these radionuclides at Murree varied from 1 to 129Bqm−2 y−1 and 17 to 2202Bqm−2 y−1 in the open lawn rain samples and from 1 to 35Bqm−2 y−1 and 9 to 975Bqm−2 y−1 in throughfall samples respectively. Similarly the annual mean flux values of both radionuclides in open lawn rain samples of Islamabad are 1137Bqm−2 y−1 and 3801Bqm−2 y−1 respectively. Observed seasonal variations of deposition of 210Pb and 7Be are explained in terms of different environmental features. The role of plantation in the interception of radionuclides in throughfall samples is analyzed and discussed. The effect of the altitude on the deposition processes at the investigated site is studied using the comparison of present results with the relevant published results and analysis. [Copyright &y& Elsevier]