CR-39 Solid State Nuclear Track Research Articles

Radon, Thoron and Polonium Concentrations Estimated in Building Materials Samples Collected from Al-Shatra, Dhi-Qar, Iraq

Radon, Thoron and their short-lived daughters have a high contribution to background radiation, as long-term exposure causes the risk of lung cancer. In current study, five types of building materials with a total 55 samples in Al-Shatra City, Dhi-Qar Governorate, Iraq collected to measure the radon and thoron concentration by using CR-39 solid state nuclear track detector. The results showed that the average radon concentrations in all samples were (103.53±55.94) Bqm−3, while the average thoron concentration was (53.20±44.69) Bqm−3. On the other hand, the annual effective dose of radon ranged between (0.85-6.46) msvy−1, with an average of 2.61msvy−1. While, for thoron concentration was ranged between (0.12-3.28) msvy−1, with an average of 1.49 msvy−1. The annual effective dose was found acceptable limit (3-10 msvy−1) recommended by the International Commission on Radiological Protection (ICRP). On the other side, the average Polonium concentrations (218Po, 214Po) have been found to be 2.053 KBqm−3, 0.866 KBqm−3, respectively.

A study of 226Ra concentration and radon exhalation rates in different geopolymer cement samples using CR-39 solid state nuclear track detector

Radon is a naturally occurring radioactive gas that is known to cause lung cancer. Therefore, it is essential to measure and determine the concentration of radon in different materials. The purpose of this research is to measure and analyze the levels of radon concentration, radium concentration, and radon exhalation rates in various geopolymer cement mixes. These mixes are made from slag or metakaolin blended with different ratios of fly ash, silica fume, and cement kiln dust. The main goal is to determine the potential risks associated with using geopolymer cement materials in construction and how they may impact indoor air quality. To achieve this, the study will monitor the amounts of radon released from different geopolymer cement mixes and compare them to traditional cement samples. A CR-39 solid-state nuclear track detector will be used for monitoring purposes. Results of this study have revealed that the radon concentration varies from 4.03 to 348.21 Bqm−3 with an average value 62.01 Bqm−3. Radium concentration also changes from 15.18 to 926.47 Bqkg−1 with an average value 174.23 Bqkg−1. The value of the dissolved radon concentration in the collected samples alters from 4.57 to 394.87 Bqm−3 with an average value 70.32 Bqm−3. The mass exhalation rates are found to vary from 0.04 to 2.28 Bqkg−1h−1 with an average value 0.43 Bqkg−1h−1, while the surface exhalation rates vary from 0.91 to 78.92 Bqm−2h−1 with an average value 14.06 Bqm−2h−1. The Annual Effective Dose (AED), due to conducting the experiment indoors, has varied from 0.102 to 8.785 mSvy−1 with an average value 1.564 mSvy−1, where AED in the outdoor experiment has varied from 0.038 to 3.294 mSvy−1 with an average value 0.587 mSvy−1. According to the results, the geopolymer mixes labeled as (S) and (SS) containing 100% GGBFS and 85% GGBFS with 15% SF respectively has had the highest levels of radium concentration, radon concentration, dissolved radon concentration, radon exhalation rates, and AED. The investigation results indicate that, with the exception of samples (S) and (SS), the analyzed samples fall within the suggested range of acceptable values. Based on our results, it seems that all geopolymer samples except for (S) and (SS) are safe for being used in building materials production. We recommend utilizing these samples (S, SS) for public highways, bridges, and other buildings that have good ventilation.

Estimating annual effective dose and excess of the lung risk factor of radon gas in University of Al-Hamdaniya buildings

Radioactive radon gas is a source of environmental pollution, especially in places where radon levels are high. Radon gas concentrations must be kept at their lowest levels and below globally acceptable limits for a safe environment, which can be accomplished by taking frequent measurements to identify and fix high concentration areas. In this study, radon gas concentration was measured in the air of several buildings of the University of Al-Hamdaniya using the CR-39 solid state nuclear track detector. The measured radon concentrations ranged from 19.24 to 64.60 Bq.m−3, with an average of 41.54 Bq.m−3. The effective annual dose ranged from 0.48 to 1.62 mSv/y. The lifetime cancer risk was 1.86 × 10−3 to 6.26 × 10−3. The mean radon concentration obtained was less than the World Health Organization reference level of 100 Bq.m−3.

New Inorganic Boron Assessment in environmental Samples by Neutron Activation Analysis using CR-39 Solid State Nuclear Track Detectors.

A new trend in applying nuclear solid-state track detector CR-39 for neutron activation assessment of inorganic boron compounds in environmental samples was established. The nuclear reaction 10B(n, α)7Li was selected for this purpose by using gelatin film for a sample application. It possesses many advantages such as time saving, sensitivity, and reproduciblity, and many related variables were studied. Linearity was found at the range of 1.0 - 12.5 ppm and at 10.0 -250 ppm with different slopes. There were no interfering nuclei among the naturally abundant elements and their isotopes, viz. Al, O, Na, Cl, P, Ca, Si, K, and Cu. It was applied to determine boron in simulated environments and industrial soil and water samples, with recovery within the range of 96-100 %, good precision and accuracy + 1.5 - 3.0 %. The method sensitivity can be enhanced by using longer irradiation time, and few micrograms of boron can be analysed, and hence it is more suitable to be used in the activation analysis system of nuclear reactors.

Dose rates evaluation of some granitic rocks from the Paraná State

Granitic rocks, widely used as building materials, are known to contain natural radionuclides and can be an important source of radiation for the population. Thirty-four samples of granite rocks from geological occurrences in Paraná state were measured with an HPGe detector for evaluation of226Ra, 232Th and 40K activity concentrations. The effective annual external dose was evaluated from these radionuclides activities using a dosimetric room model with dimensions 4 m x 5 m x 2.8 m in which all wallsare internally coated with granites of thickness 2 cm and considering an annual exposure time of 7000 h. This value was suggested by the European Commission on Radiological Protection for superficial coating materials. The internal exposure was evaluated from radon air concentration of the model room, simulated from an exhalation rate of 222Rn, determined with CR-39 solid state nuclear track detectors using the sealed can technique, considering a ventilation rate of 0.5 h-1 and an annual exposure time of 7000 h. The results of this study showed that the increase in the annual effective dose ranged from 62 ± 3 μSv.a-1 to 138 ± 1 μSv.a-1 from external gamma rays and the increase in the annual effective dose ranged from 0.39 ± 0.04 μSv.a-1 to 70 ± 4 μSv.a-1 from radon inhalation. All results stayed below 1 mSv.a-1 recommended by the European Commission on Radiological Protection.

Radiological risk assessment of some consumed cigarettes and hookah in Iraq

The main purposes of the research are to assess the radiological risk due to smoking cigarettes and hookah and their impacts on the people health. Radon levels were measured in 28 consumed brands of cigarettes and 10 brands of hookah consumed Iraq using CR-39 solid state nuclear track detectors (SSNTDs). The results showed that the 222Rn concentration in cigarette tobacco samples ranged from 138.9 to 781.2 Bqm-3 with average value of 318.0 Bqm-3. The radon concentrations emerged from 11brands of the investigated samples was significantly higher than the recommended value. While, its concentration in hookah ranged from 633.6 Bqm-3 to 416.6 Bqm-3 with average value of 509.5 Bqm-3. The Potential Alpha Energy Concentration (PAEC) in terms of (WL) units, Exposure to radon progeny (EP), and the annual effective dose (AED) in terms of (mSv/y) units were also obtained. Lung cancer cases per year per million people (CPPP) are also evaluated with an average value of 144.4 per million people. The result indicates that the average values of PAEC, EP and AED were within the recommended range values given by UNSCEAR, NCRP and ICRP respectively. The radioactive impact of smoking is considered as a risk factor for lung cancer.

The influence of shielding reinforcement in a vault with limited dimensions on the neutron dose equivalent in vicinity of medical electron linear accelerator.

BackgroundHigh energy electron linear accelerators (LINACs) producing photon beams with energies higher than 10 MeV are widely used in radiation therapy. In these beams, fast neutrons are generated, which results in undesired contamination of the therapeutic beam. In this study, measurements and Monte Carlo (MC) simulations were used to obtain neutron spectra and dose equivalents in vicinity of linear accelerator.Materials and methodsLINAC Siemens Oncor Expression in Osijek University Hospital is placed in vault that was previously used for 60Co machine. Then, the shielding of the vault was enhanced using lead and steel plates. Measurements of neutron dose equivalent around LINAC and the vault were done using CR-39 solid state nuclear track detectors. To compensate energy dependence of detectors, neutron energy spectra was calculated in measuring positions using MC simulations.ResultsThe vault is a source of photoneutrons, but a vast majority of neutrons originates from accelerator head. Neutron spectra obtained from MC simulations show significant changes between the measuring positions. Annual neutron dose equivalent per year was estimated to be less than 324 μSv in the measuring points outside of the vault.ConclusionsSince detectors used in this paper are very dependent on neutron energy, it is extremely important to know the neutron spectra in measuring points. Though, patient dosimetry should include neutrons, estimated annual neutron doses outside the vault were far below exposure limit of ionizing radiation for workers.

Simple and low cost alternative method for detecting photoneutrons produced in some radiotherapy treatments using SSNTDs

A simple and low cost alternative which is able to identify thermal and fast neutrons in a clinical environment of radiotherapy is presented. CR-39 and LR-115 Solid State Nuclear Track Detectors (SSNTDs) were used, estimating their viability. In order to register alpha tracks due to thermal neutrons, natural boric acid tablets were placed in close contact to the detector, whereas in order to detect epithermal neutrons, some were additionally covered in a thin cadmium layer. Different configurations were assembled, changing the position of the converter with respect to the detector and the incident neutron fluence, which was evaluated in different positions of a radiotherapy table. The contribution due to environmental 222Rn and its daughters to the track density registered by the detector during the measurements was found to be negligible. It is concluded that the designed experimental set up constitutes a trustworthy and affordable method to carry out neutron measurements with the recommended configurations provided for the CR-39 detector, and not with LR-115.

Assessment of arrangements for the detection of radon emanating from soil

CR-39 solid state nuclear track detectors were used to measure radon (222Rn) concentration in the soil near ground surface. The measurements were performed in the campus of the University of Ioannina, using PVC tubes at 0.25 m intervals down to depths of 1.25 m. The track detectors were etched in 7N NaOH solutions at 80°C. The tracks were counted using a microscope - camera - computer system, developed for automatic counting. The results provide evidence for the non-diffusive transport of radon in soils. A transport length of (46.9 ± 3.2) cm was estimated for radon transport near ground surface. Also the variation of soil's radon was correlated to meteorological variations.

A Comparative Study of Photo-Neutron Production from Flattened and Unflattened Beams in a Medical Linear Accelerator

High energy x-rays from a medical linear accelerator (LINAC) is used to treat cancer patients in radiotherapy department. The medical linac can produce bremsstrahlung x-rays from 4MV to 18MV and the commonly used linac produces 6MV, 10 MV and 15MV photons for treating major parts of the cancer patients. The photo neutron production during the radiation treatment is one of the major issues which have to be addressed with high impact because of the high LET nature associated with it. Photo neutrons are produced from several high atomic number (Z) elements present in the linac head mostly by the (ɣ, n) reaction. The flattening filter used in medical linac to produce uniform intensity distribution (made up of either tungsten, steel, lead, uranium, aluminum or a combination) is one of the photo neutron sources in the linac head. Advanced radiotherapy treatments like Intensity Modulated Radiotherapy (IMRT) and Volumetric Arc Therapy (VMAT) doesn't require a flat radiation field, and hence the flattening filter could be removed. This is called flattening filter free beam (FFF beam)1, 2. The removal of the filter will result in a forward peaked photon beam, which is very advantageous for these kinds of treatments3, 4. The purpose of this work was to find out the difference in the percentage of photo neutron production in a flattening filter free (FFF) and flattening filter (FF) beam using CR39 Solid State Nuclear Track Detector (SSNTD) from an Elekta Versa HD machine. The neutron fluence was measured at different positions with FFF and FF mode and the results were tabulated. The neutron fluence was lower for the FFF mode of operation than the FF mode. The reduction ranges from 2.27% to 44.22%.

Detection of plated-out radon progenies on CR-39 detectors

A spectrometric study of alpha particles using CR-39 solid state nuclear track detectors is described. It is based on the application of software imposed selection criteria, concerning the geometrical and optical properties of the tracks which are created by alpha particles of specific energy falling on the detector at given angles of incidence. These selection criteria are based on a preliminary study of tracks’ parameters (major and minor axes and mean value of brightness), using the TRIAC II code. Since no linear relation was found between the energy and the geometric characteristics of the tracks (major and minor axes), we resorted to the use of an additional parameter in order to classify the tracks according to the particles’ energy. Since the brightness of tracks is associated with the tracks’ depth, the mean value of brightness was chosen as the third parameter. This method could be applied as a low cost technique in studies concerning the radon’s daughters 218Po and 214Po behavior in air.

A new chemical etchant for the development of alpha tracks in CR-39 solid state nuclear track detector

Chemical etching is an important step for enlargement of latent tracks in solid state nuclear track detectors (SSNTD). In the etching process, bulk and track etch rates are determined by various parameters, which decide the sensitivity and efficiency of the track detector. Thus, determination of the etching parameters is essential in introducing a new chemical etchant. For the enlargement of latent tracks in CR-39, chemical etching is usually carried out at temperatures of 60–70 °C by using 6–6.5 N concentrations of alkali like NaOH or KOH. In the present work, a mixture of 8 g NaOH in 25 mL water and 25 mL ethanolamine as an etchant at 70 °C was found to be very effective in the enlargement of alpha tracks in CR-39 SSNTD. The diameters of alpha tracks resulting from this new etchant are found to be a quadratic function of the etching time, whereas those from the standard etchant are linear with respect to the etching time. This results in the reduction in the etching time by a factor of 4 with an increased etching efficiency.

Analysis of Photo Neutron Dose to Patient from a 15 MV Linear Accelerator

Medical Linear Accelerator produces high-intensity bremsstrahlung beam, with typical energy ranges from 4 to 18MV for treatment purposes. The materials including patient exposed to this high energy spectrum lead to a photonuclear reaction in them. In these Photon energy domains, photo neutron production (n, p, and γ, n) is the major reaction channel. This is important as Carbon, Oxygen, Hydrogen, and Nitrogen are the predominant elements in a typical human being and having low photon neutron threshold. Apart from this, the equipment involved in a radiation treatment including Head, Couch, immobilization accessories, etc contributes to photo neutron production. The present study was recorded and analyzed the photo neutron spectra due to 15 MV medical linear accelerator using CR-39 Solid State Nuclear Track Detector and image processing software.

Radon concentration measurements in sludge of oil fields in North Oil Company (N.O.C.) of Iraq

In this study the assessment radon concentration in sludge of OilFields in North Oil Company (N.O.C.) of Iraq have been studiedusing CR-39 solid–state nuclear track detector technique. A total of34 samples selected from 12 oil stations in the company have beenplaced in the dosimeters. The average radon concentration was foundto be 162.29 Bq/m3 which is fortunately lower than the standardinternational limit. The potential alpha energy concentration andannual effective dose have been calculated. A proportionalrelationship between the annual effective dose and radonconcentration within the studied region has been certified.

Radon Concentration Measurements in Gattar Uranium Prospect, Northern Eastern Desert, Egypt

The concentration of Radon in mines varies tremendously according to the country rock, type of mineralization and area. Ventilation is also an important factor. The absence of ventilation in mines tends to allow a higher concentration of Radon to build up. This is very dangerous for the miners work inside. In this present work, the radon gas concentration is practically measured in closed uranium prospect mine located at Gabal (G.) Gattar. CR-39 solid state nuclear track detector technique is used. It is found that the radon concentration is around 80 kBq m-3 and an effective ventilation rates should be applied if there will be further works in the future.

An experimental cross-section measurement of 10B(n,α)7Li reaction on counting alpha particles track density

The present work determines the particle size based only on the number of tracks detected in a cluster created by a hot particle on the CR-39 solid state nuclear track detector and depending on the exposure time. The mathematical model of the cross section developed here gives the relationship between alpha particle emitting from the (n, α) reaction and the number of tracks created and distribution of tracks created on the surface of the track detector. In an experiment performed during this work, disc of boron compound (boric acid or sodium tetraborate) of different weights were prepared and exposed to thermal neutron from the source. Chemical etching is processes of path formation in the detector, during which a suitable etching solution attacks the detector at a sufficient speed and the damaged regions along the ion trails (latent track) are preferentially dissolved, removed and get transformed into a hollow channel. The most common etching for plastics is the aqueous solutions of NaOH and temperatures in between 50˚C - 80˚C.The program (CR-39) processing counting and calculations only take place depending on the number of tracks.

Radon Concentration Measurement in Ainkawa Region Using Solid State Nuclear Track Detector

Radon is the air contaminant radioactive gas which people exposed to, is a reason for lung damages and lung cancer. The areas that are subject to high radon levels are found by radon concentration measurement. The radon activity concentration, annual effective dose, and potential alpha energy concentration (PAEC), were measured in houses of Ainkawa region using CR-39 solid state nuclear track detectors SSNTDs with the sealed-can technique. In the present paper the estimated values for radon activity concentration are in the range 55.99-112.8 Bq/m 3 with 84.30 Bq/m 3 as a mean value, the range of annual effective dose are 1.411-2.872 mSv/y , with mean value 2.124 mSv/y , and the potential alpha energy concentration range are 6.0533-12.323 mWL with mean of 9.1133 mWL . The mean value of the radon concentration is below of 100 Bq/m 3 the reference level of (WHO) World Health Organization, and well below of UK National Radiation Protection Board (NRPB) and European Commission Recommendation Level of 200 Bq/m 3 .

Detection of high energy particles using CR-39 detectors Part 2: Results of in-depth destructive etching analysis

We have performed Pd electrodeposition in both D2O and H2O electrolytes in the presence of a magnetic field using CR-39 solid state nuclear track detectors. These detectors were either immersed in the electrolyte or separated from it by a thin Mylar® film. We have found a statistically significant increase in the number of tracks measured in the D2O experiments when compared to the H2O experiments.

Developing a Fast Affordable Automatic Counting System of CR-39 Solid State Nuclear Track Detectors

Developing a Fast Affordable Automatic Counting System of CR-39 Solid State Nuclear Track Detectors

Studies of radioactive contaminations and heavy metal contents in cosmetics

Measurement of radioactivity in cosmetics such as face powders and eye liner (kohl) has not been reported so far. Herein gamma ray spectrometry and CR-39 solid state nuclear track detector have been used to investigate six cosmetics of different brands. The results have demonstrate that the average values of specific activities of 238U, 232Th and 40K were 12.66±2.96, 14.58±8.83 and 269±120 Bqkg−1, respectively. Also the average radon exhalation rate was 0.21±0.04 Bqm−2h−1. The calculated radium-equivalents were lower than recommended value (370 Bqkg−1). The absorbed dose rates due to the natural radioactivity of the investigated samples ranged from 6.83±2.6 to 99.5±51 nGyh−1. Also, X-ray fluorescence spectrometry studies showed that the concentrations of the heavy Mo, Sr, Pb, Zn, Cu, Ni, Fe, Mn, Rb, As, Zr and Cr were 4±0.96, 26.93±12.24, 110135±109973, 672.98±433, 1001±722, 318±145, 3847±790, 60±25, 24.71±13, 9002±4210, 24.71±18 and 153±72 ppm, respectively.