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Hosseini Pooya S.M.,Iran Nuclear Regulatory Authority | Hosseini Pooya S.M.,Nuclear Science and Technology Research Institute, Iran | Taheri M.,Iran Nuclear Regulatory Authority
Applied Radiation and Isotopes | Year: 2013

Based upon the steady flow method, a setting has been introduced for fast calibration of almost all types of active and passive radon detectors. In this method, a traceable radon reference flow-through sources is connected to a portable rectangular cubic transparent chamber (volume of 50. L) which is completely sealed and has 6 valves on its sides. The initializing calibration times are less than 150. min by this chamber. The radon concentration in the chamber is in consistent with the source activity. The Best Measurement Capability (BMC) of the method has been calculated less than 5% at 68% confidence level. As well by using grab-sampling method, the difference of radon concentration of different points in the chamber was measured less than 1.2%. So the flow-through sources can be developed for a fast calibration of almost all types of the radon monitors with an acceptable uncertainty using this calibration setting. © 2012. Source

Mianji F.A.,Nuclear Science and Technology Research Institute, Iran | Jafari S.,Bu - Ali Sina University | Zaryouni S.,Bu - Ali Sina University | Hajizadeh B.,Iran Nuclear Regulatory Authority
Radiation and Environmental Biophysics | Year: 2015

Dosimetry bioassay methods are the backbone of a personal dosimetry in criticality accidents. Although methods like hair dosimetry and the use of activation foils (e.g., 32S) have been employed for decades, capabilities of different techniques, effects of hair type and neutron spectrum on the dose response, sensitivity and uncertainties of different techniques, etc., need more investigations. For this reason, the use of the 32S(n,p)32P reaction and hair samples for estimating non-fatal doses from fast neutrons was studied. The experiments were carried out with the hair samples attached on a RANDO phantom in a Cf-252 neutron field, in the dose range of about 0.05–1.15 Gy. In addition, the adequate post-accident preparation for hair samples including optimum conditioning and timing were investigated. Experimental results prove the good sensitivity and merit of the method for neutron quantification in the mentioned dose range for which other bioassay methods are of poor resolution and sensitivity. A rough estimation of the dose–response curve for Iranian hair was also derived. © 2014, Springer-Verlag Berlin Heidelberg. Source

Mianji F.A.,Nuclear Science and Technology Research Institute, Iran | Diba J.K.,Iran Nuclear Regulatory Authority | Babakhani A.,Nuclear Science and Technology Research Institute, Iran
Radiation Protection Dosimetry | Year: 2014

Unrecognised pregnancy during radioisotope therapy of thyroid cancer results in hardly definable embryo/fetus exposures, particularly when the thyroid gland is already removed. Sources of such difficulty include uncertainty in data like pregnancy commencing time, amount and distribution of metastasized thyroid cells in body, effect of the thyroidectomy on the fetus dose coefficient etc. Despite all these uncertainties, estimation of the order of the fetus dose in most cases is enough for medical and legal decision-making purposes. A model for adapting the dose coefficients recommended by the well-known methods to the problem of fetus dose assessment in athyrotic patients is proposed. The model defines a correction factor for the problem and ensures that the fetus dose in athyrotic pregnant patients is less than the normal patients. A case of pregnant patient undergone post-surgical therapy by I-131 is then studied for quantitative comparison of the methods. The results draw a range for the fetus dose in athyrotic patients using the derived factor. This reduces the concerns on under-or over-estimation of the embryo/fetus dose and is helpful for personal and/or legal decision-making on abortion. © The Author 2014. Source

Ab Azar N.,Iran Nuclear Regulatory Authority | Babakhani A.,Islamic Azad University at Tehran | Broumandnia A.,Islamic Azad University at Tehran | Sepanloo K.,Iran Nuclear Regulatory Authority
Radiation Measurements | Year: 2016

Overlapping object detection and counting is a challenge in image processing. A new method for detecting and counting overlapping circles is presented in this paper. This method is based on pattern recognition and feature extraction using "neighborhood values" in an object image by implementation of image processing techniques. The junction points are detected by assignment of a value for each pixel in an image. As is shown, the neighborhood values for junction points are larger than the values for other points. This distinction of neighborhood values is the main feature which can be utilized to identify the junction points and to count the overlapping tracks. This method can be used for recognizing and counting charged particle tracks, blood cells and also cancer cells. The method is called "Track Counting based on Neighborhood Values" and is symbolized by "TCNV". © 2016 Elsevier Ltd. All rights reserved. Source

Bavarnegin E.,Guilan University | Fathabadi N.,Iran Nuclear Regulatory Authority | Vahabi Moghaddam M.,Guilan University | Vasheghani Farahani M.,Iran Nuclear Regulatory Authority | And 3 more authors.
Journal of Environmental Radioactivity | Year: 2013

Radon exhalation rates from building materials used in high background radiation areas (HBRA) of Ramsar were measured using an active radon gas analyzer with an emanation container. Radon exhalation rates from these samples varied from below the lower detection limit up to 384 Bq.m-2 h-1. The 226Ra, 232Th and 40K contents were also measured using a high resolution HPGe gamma- ray spectrometer system. The activity concentration of 226Ra, 232Th and 40K content varied from below the minimum detection limit up to 86,400 Bq kg-1, 187 Bq kg-1 and 1350 Bq kg-1, respectively. The linear correlation coefficient between radon exhalation rate and radium concentration was 0.90. The result of this survey shows that radon exhalation rate and radium content in some local stones used as basements are extremely high and these samples are main sources of indoor radon emanation as well as external gamma radiation from uranium series. © 2012 Elsevier Ltd. Source

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