LR-115 Solid State Nuclear Track Research Articles

Assessment of indoor radon concentration in the dwellings of the industrial areas of Kannur District, Kerala.

All organisms on the earth-crest are exposed to natural background radiation since the evolution of the earth, as many environmental matrices such as soil, air, water bodies, vegetation, etc., act as the sources of natural radioactivity. The present study deals with the evaluation of indoor concentration of 222Rn (radon) in different dwellings with various construction materials used for the roof and floor in the industrial sites of Kannur district, Kerala. A pinhole-based dosemeter coupled with LR-115 Solid State Nuclear Track Detector and Direct Radon Progeny Sensor (DRPS) were respectively used for the measurement of indoor radon concentration and equilibrium equivalent concentration of radon. The indoor radon concentrations were found to vary from 102.30 Bqm-3 to 184.75 Bqm-3 and the values were within the recommended limits provided by International Commission on Radiological Protection (ICRP). The annual effective doses and excess lifetime cancer risks were observed in the range of 2.58-4.66 mSvy-1 and 7.68×10-3-15.60×10-3, respectively, and both exceed the world average values recommended by United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) 2000. The study shows that, the houses with marble floors and concrete roofs have comparatively higher values of radon concentration, which indicates the significant contribution of construction materials to the enhanced radiation levels inside the dwellings.

Radon Concentrations in the Environments of Some Primary Schools in Khidir City, Al-Muthanna Province, Iraq

Indoor radon concentrations in 13 primary schools were conducted in Khidir City, Muthanna Province, Iraq, using LR-115 solid-state nuclear track detector type II. The study aims to estimate indoor radon levels in the internal environment of the classrooms for three months (from 1st September to 30th November 2023). Radon concentrations were varied from (0.1 Bq/m3) to (14.13 Bq/m3), with a mean value of (5.61 Bq/m3). The investigated levels were lower than the permissible limits referenced by UNSCEAR and WHO. Moreover, the annual effective dose (AED) has been calculated due to inhalation, which varied from the value of (0.029352 mSv/yr) to the value of (0.081145 mSv/yr), with a mean value of (0.016205 mSv/yr). AED values obtained were found to be lower than the allowed value of (0.1 mSv/yr) reported by UNSCEAR and much lower than the permissible limit (1 mSv/yr) proposed by WHO. However, the results obtained indicate that the indoor radon concentrations were significantly affected by the floor level of the classroom (negatively correlated) and the school building age (positively correlated). Consequently, all results have revealed that the radon concentrations and the associated inhalation radon dose does not pose any kind of health hazard to the occupational stuff and students.

Time-efficient etching of LR-115 SSNTD film for indoor radon, thoron quantification.

LR-115 Solid State Nuclear Track Detector (SSNTD) is commonly utilized for quantifying indoor radon-thoron levels, by tallying the tracks formed in the films by exposure to these gases. Conventionally, sodium hydroxide (NaOH) is used to etch LR-115 films for 90 min at 60°C. However, this study suggests a time-efficient alternative approach utilizing potassium hydroxide (KOH) as the etchant. In an initial investigation, the bulk etch rates of KOH were examined at different normalities and temperatures, revealing that KOH exhibited nearly double the bulk etch rates compared to NaOH. Subsequently, a specially designed controlled experiment was conducted to assess the efficacy of the technique by enumerating the tracks generated in the films. Both etchants demonstrated very similar track counts for identical controlled exposures, indicating the reliability of the method. A consistent behavior was observed in the real-case scenario of LR-115 films exposed indoors to alpha particles from radon and its decay products. In both experiments, the etching with KOH for 45 min gave track densities comparable to standard NaOH etching for 90 min, highlighting the time efficiency of this method. Investigations were carried out into track shape and size features, aspects crucial to the measurement technique, using microscopic imaging of samples treated with both etchants. Strikingly similar track shapes and sizes were observed, affirming the consistency in the track measurement technique. Collectively, these findings suggest that KOH etchant reduces the etching time, presenting itself as a time-efficient method for quantifying radon and thoron track density.

Radon Concentration in Urban Areas in the North and West of Morocco

Radon is a colorless, odorless radioactive gas produced by the decay of uranium and radium. It is the second cause of cancer of the lungs after smoking. It has been present in Earth's crust since the creation of Earth. Uranium-rich rocks in the deep crust are the main source of radon. Its emanation from the ground surface varies from one point to another depending on the physical characteristics of the terrain crossed as observed in this study between North and West Morocco. A dosimetric study of those emanations was performed by using the LR-115 solid-state nuclear track detector (SSNTD) which was subsequently processed by techniques developed and calibrated in the laboratory. The study revealed high concentrations of this gas in confined spaces at ground level and, in particular, in basements and less-ventilated ground floor rooms. In order to reduce these concentrations of radon and the probability of carcinogenic attacks by these accumulations of this gas, it is recommended to ventilate these premises well. Good air circulation allows the removal of this harmful gas.

TIME SERIES ANALYSIS OF RADON CONCENTRATION AT DIFFERENT DEPTHS IN AN UNDERGROUND GOLDMINE

Indoor radon concentrations were collected monthly over a period of one year in 10 different levels in an underground goldmine and the data was analysed using a four moving average time series to determine the relationship between depths of the underground mine and the indoor radon concentration. The detectors were installed in batches within four quarters. The measurements were carried out using LR115 solid state nuclear track detectors. Statistical models are applied in the prediction and analysis of the radon concentration at various depths. The time series model predicted a positive relationship between the depth of the underground mine and the indoor radon concentration. Thus, elevated radon concentrations are expected at deeper levels of the underground mine, but the relationship was insignificant at the 5% level of significance with a negative adjusted R 2 (R 2 = – 0.021) due to an appropriate engineering and adequate ventilation rate in the underground mine. Keywords : LR115, Radon Concentration, Time Series, Underground goldmine, DOI: 10.7176/APTA/87-03 Publication date: April 30 th 2023

A Study on the Bulk Etch Rate of LR-115 Solid State Nuclear Track Detector using Lithium Hydroxide as an Etching Solution

A Study on the Bulk Etch Rate of LR-115 Solid State Nuclear Track Detector using Lithium Hydroxide as an Etching Solution

Estimation of Uranium Concentration in Urine Samples of Three Age Groups of Healthy Individuals in Najaf Governorate Using CR-39 and LR-115 Solid State Detectors

Uranium concentration was estimated in urine samples of three age groups, G1≤ 30 years, n=28, G2 age range of 31-40 years, n=28, and G3 of age > 40 years, n=32, using two types of detectors CR-39 and LR-115 solid-state nuclear track detector (SSNTD) for results comparison. Results showed that uranium mean level values for CR-39 were 1.961 ±0.08 µg/L, 1.810 ±0.09 µg/L and 1.814 ±0.076 µg/L for G1, G2 and G3 respectively, while the mean values of uranium concentration using LR-115 were 0.972 ±0.07 µg/L, 0.922 ±0.07 µg/L and 1.018 ±0.08 µg/L in G1, G2 and G3 respectively, with significant statistical difference between the results of CR-39 and LR-115 for each age group. Mean level values for females was 2.023± 0.09 µg/L and 1.813± 0.05 µg/L for males using CR-39 and it was 1.105± 0.09 µg/L for females and 0.933± 0.04 µg/L for males using LR-115, with significant statistical difference between results for each gender. It was concluded that G1 ≤ 30 years have the highest uranium pollution, noting that females were more polluted with uranium than males.

Dynamics of radionuclides activity, radon exhalation rate of soil and assessment of radiological parameters in the coastal regions of Kerala, India

The activity concentration of natural radionucides such as 40K, 226Ra and 232Th and radon surface and mass exhalation rates of the soil were assessed and the related radiometric parameters have been estimated from the activities of the samples from beaches of coastal Kerala including some high background radiation areas (HBRAs). The activity concentrations of 40K, 226Ra and 232Th were estimated using NaI (Tl) gamma ray spectrometry and the radon mass and surface exhalation rate has been estimated using the ‘Can technique’ with LR-115 solid state nuclear track detectors. The estimated values indicate that the radionuclide concentrations in the study area were within the recommended limit except for Kollam district when compared with world average values. Radon exhalation rate found to vary according to grain size of the soil. Dose parameters have been evaluated in order to verify the radiological protection of the general public. The results of the present systematic investigation are presented and discussed in detail in the manuscript.

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.

Quantification of an alpha flux based radiological dose from seasonal exposure to 222Rn, 220Rn and their different EEC species

This study summarizes the seasonal experimental data on the activity concentrations of indoor 222Rn (Radon), 220Rn (Thoron) and their progeny in Mansa and Muktsar districts of Punjab (India) using LR-115 solid state nuclear track detector based time integrated pin-hole cup dosimeters and deposition based progeny sensors for the assessment of radiological dose. The indoor 222Rn concentration was observed higher in the rainy and winter seasons while 220Rn concentration was observed higher in the winter season. However, Equilibrium Equivalent Concentrations (EECs) of 222Rn and 220Rn exhibited distinct seasonal behaviour unlike their parent nuclides. The average equilibrium factors for 222Rn (FRn) and 220Rn (FTn) were found 0.47 ± 0.1 and 0.05 ± 0.01, respectively. The annual arithmetic means of unattached fractions of 222Rn ({f}_{p}^{Rn}) and 220Rn ({f}_{p}^{Tn}) were found to be 0.09 ± 0.02 and 0.10 ± 0.02, respectively. The attachment rate (XRn) and attachment rate coefficients (β) of 222Rn progeny were also calculated to understand the proper behaviour of progeny species in the region. A new alpha flux based technique has been proposed and used for the assessment of absorbed dose rate and annual effective dose rate for radiation protection purpose.

MEASUREMENT OF INDOOR RADON-THORON IN AIR AND EXHALATION FROM SOIL IN THE ENVIRONMENT OF WESTERN HARYANA, INDIA.

Measurement of indoor radon and thoron is important because the inhalation of radon-thoron and their daughters contributes more than 50 % of the total dose from natural sources. One of the important parameters to find out the contribution of soil and building materials towards indoor radon is radon exhalation rates, which can be used for estimation of indoor radon levels. The indoor radon and thoron levels from the air and radon exhalation rates from soil samples collected from two districts (Hisar and Fatehabad) of Western Haryana are measured using pin-hole-based radon-thoron dosimeter and LR-115 solid-state nuclear track detector by canister technique. The results show that the indoor radon and thoron levels from Hisar district varied from 11 to 112 and 11 to 80 Bq m-3, while for Fatehabad district from 5 to 24 and 59 to 105 Bq m-3, respectively, in summer season. In winter season, indoor radon and thoron levels from Hisar district varied from 15 to 43 and 32 to 102 Bq m-3, while for Fatehabad district from 18 to 31 and 11 to 80 Bq m-3, respectively. The indoor radon levels of 95 % locations lie well below the limit recommended by International Commission of Radiation Protection, 2011. The radon mass exhalation rate varied from 6 to 56 mBq kg-1 h-1 The radon mass exhalation rates from the soil samples were lower than the worldwide average, i.e. 56 mBq kg-1 h-1 There exists a poor correlation between indoor radon and exhalation rates. More investigations of measurement of radionuclide contents from rock and stone of study area can improve the understanding.

STUDY OF RADIATION EXPOSURE DUE TO RADON, THORON AND THEIR PROGENY IN THE INDOOR ENVIRONMENT OF RAJPUR REGION OF UTTARAKHAND HIMALAYA.

In the present study, the measurements of indoor radon, thoron and their progeny concentrations have been carried out in the Rajpur region of Uttarakhand, Himalaya, India by using LR-115 solid-state nuclear track detector-based time-integrated techniques. The gas concentrations have been measured by single-entry pin-hole dosemeter technique, while for the progeny concentrations, deposition-based Direct Thoron and Radon Progeny Sensor technique has been used. The radiation doses due to the inhalation of radon, thoron and progeny have also been determined by using obtained concentrations of radon, thoron and their progeny in the study area. The average radon concentration varies from 75 to 123 Bq m-3 with an overall average of 89 Bq m-3 The average thoron concentration varies from 29 to 55 Bq m-3 with an overall average of 38 Bq m-3 The total annual effective dose received due to radon, thoron and their progeny varies from 2.4 to 4.1 mSv y-1 with an average of 2.9 mSv y-1 While the average equilibrium factor for radon and its progeny was found to be 0.39, for thoron and its progeny, it was 0.06.

Measurements of radon and thoron progeny concentrations in dwellings of Tehri Garhwal, India, using LR-115 deposition-based DTPS/DRPS technique.

This paper presents the values of radon and thoron progeny concentrations for different seasons in the dwellings of Tehri Garhwal, India. The measurements have been carried out using LR-115 solid-state nuclear track detector-based passive time-integrated direct thoron progeny sensor/direct radon progeny sensor technique. In summer, the radon and thoron progeny have been found to vary from 5.7±0.8 to 153.2±4.3 Bq m(-3) with an average of 37.6 Bq m(-3) and 0.3±0.06 to 3.2±0.19 Bq m(-3) with an average of 1.3 Bq m(-3), respectively. In the rainy season, the radon and thoron progeny have been found to vary from 3.2±0.6 to 120±3.7 Bq m(-3) with an average of 58.2 Bq m(-3) and 0.2±0.05 to 11.3±0.37 Bq m(-3) with an average of 3.4 Bq m(-3), respectively. In autumn, the radon and thoron progeny have been found to vary from 4.1±0.7 to 374.4±6.7 Bq m(-3) with an average of 95.6 Bq m(-3) and from 0.3±0.06 to 30.5±0.60 Bq m(-3) with an average of 6.6 Bq m(-3), respectively. In winter, the radon and thoron progeny have been found to vary from 9.8±1.1 to 188.9±4.8 Bq m(-3) with an average of 70.7 Bq m(-3) and 0.1±0.03 to 7.5±0.30 Bq m(-3) with an average of 2.3 Bq m(-3), respectively. It has been observed that the average value of radon and thoron progeny concentrations is maximum for autumn and minimum for summer seasons. The seasonal variations in radon and thoron progeny concentrations in different houses are discussed in detail.

Indoor radon activity concentration measurements in the great historical museums of University of Naples, Italy.

Indoor radon activity concentrations were measured in seven Museums of University of Naples, very old buildings of great historical value. The measurements were performed using a time-integrated technique based on LR-115 solid-state nuclear track detectors. The annual average concentrations were found to range from 40 up to 1935 Bq m(-3) and in 26 % of measurement sites, the values were higher than 500 Bq m(-3) which is the limit value of Italian legislation for workplace. Moreover, we analysed the seasonal variations of radon concentrations observing the highest average in cold weather than in warm.

Measurement of Radon Concentrations and Annual Dose Rate in some Regions of Baghdad City using LR-115 Nuclear Track Detector

In this work, LR-115 solid state nuclear track detector used to measure the indoor and outdoor radon concentrations, the annual absorbed dose rate and annual effective dose rate to the lung, were measured in nine houses at different places of Baghdad city, the observed values of indoor and outdoor radon concentrations was in range of 14.7-46.17 Bq/m 3 and 9.69–35.69 Bq/m 3 respectively. The resulting concentration of Short-lived radon daughters expressed in term of an equilibriumequivalent radon concentration (EEC), the minimum and maximum indoor results of (EEC) was 5.88-18.46 Bq/m 3 and the outdoor results was 6.78-24.98 Bq/m 3 . The Potential Alpha Energy (PAE) concentration expressed in Working Level (WL) units was in the range of 1.58-4.99 mWL in indoor and 1.8-6.75 mWL in outdoor regions. The annual effective dose calculated according to the radiation weighting (WR) factor for alpha particles and the tissue weighting (WT) factor and the annual absorbed dose rate, the present results confirmed that the radon gas concentrations in all the nine places of Baghdad city are lower than the International Commission Radiation Protection (ICRP) agency, recommended value (200Bq/m 3 ).

Geological significance of radon gas in soil and underground water: A case study of Nurpur area, District Kangra, Himachal Pradesh, India

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.

Assessment of Radiological Levels at Schools in Trabzon, Turkey

In this study, a survey on environmental radioactivity in 16 high schools located in north eastern region of Turkey (the black sea region, province of Trabzon) was carried out. Indoor air radon (222Rn) concentrations were measured in spring and autumn 2008 seasons using LR115 solid state nuclear track detectors and gamma radioactivity levels were measured using an HPGe gamma ray detector. It was seen that mean radon activity concentrations in schools ranged from 31 to 157 Bq/m3 for spring season and from 38 to 114 Bq/m3 for autumn season. The mean gamma activity concentrations in located areas of schools are between 18–52, 21–59, 11–97 and 265–759 Bq/kg for 226Ra, 232Th, 137Cs and 40K, respectively. The annual effective doses of students and staff received due to radon and locations’ gamma radioactivity levels are calculated.

Seasonal variation of radon level and radon effective doses in the Catacomb of Kom EI-Shuqafa, Alexandria, Egypt

Inhalation of radon has been recognized as a health hazard. In the present work radon concentration was measured, in the atmosphere of the archaeological place, namely Catacomb of Kom El-Shuqafa, in Alexandria, Egypt, which is open to the public, using time-integrated passive radon dosimeters containing LR-115 solid-state nuclear track detector. The measurements were performed throughout winter and summer. Seasonal variation of radon concentration, with the maximum in summer ranging from 243 to 574 Bq m − 3 and minimum in winter ranging from 64 to 255 Bq m − 3 was observed. Because of the variations of the catacomb ventilation system, the equilibrium factor between radon and its progeny ranges from 0.14 to 0.48. The tour guides are exposed to an average estimated annual effective dose ranging from 0.21 to 0.52 mSv y − 1 and the visitors from 0.88 to 2.28 μSv y − 1. The effective doses the catacomb workers are exposed to ranged from 0.20 mSv y − 1 in winter to 4.65 mSv y − 1 in summer which exceeds the lower bound of the recommended level (3–10 mSv y − 1) (ICRP, 1993).

Measurement of bulk etch rate of LR115 detector with atomic force microscopy

Equations for calculating track parameters have been proposed, which invariably involve the track etch rate V t and the bulk etch rate V b. The present study measured V b for the LR115 solid-state nuclear track detector using atomic force microscopy (AFM). The detectors were partially masked using rubber cement and then etched in 2.5 N NaOH solution at 60°C for time periods ranging from 5 to 40 min . The rubber cement was then peeled off and cross-sectional images of the LR115 detectors were obtained by AFM. V b has been found to have different values below and beyond the etching time of about 13.5 min , with the values of 0.0555 and 0.0875 μm min −1 , respectively. The increase in V b with the etching time can be explained by a diffusion-etch model, in which the additional damage of the detector material is due to those etchant ions diffused into the detector over time. Now that V b has been determined, this can be combined with the track etch rate V t to calculate track parameters.

The influence of the soil and plant natures and pollution on the radon and thoron alpha-activities inside various herbal infusions by using solid state nuclear track detectors

Uranium and thorium contents were determined in samples of various plants in the soils in which the plants were grown, and in herbal infusions made by boiling the plants in potable water, using CR-39 and LR-115 solid state nuclear track detectors. In addition, radon and thoron alpha-activities per unit volume inside the plants, soils and herbal infusions were measured. These measurements were completed by an investigation of the radon transfer between soils and plants and that between plants and herbal infusions, and also by the investigation of the influence of pollution due to different material dusts on the radon and thoron alpha activities inside the plants and their infusions.