Prototype of a primary calibration system for measurement of radon activity concentration

New-designed measurement device for radon and thoron activity concentration based on gas direct detection

A new-designed measurement device for radon and thoron activity concentration is developed based on gas direct measurement to support their in-situ calibration. It consists of a 2000 mm2 Passivated Implanted Planar Silicon (PIPS) detector, a Multi-Channel Analyzer (MCA), a Micro Controller Unit (MCU), and a small electrostatic chamber with a volume of nearly 23 ml. The device records those alpha particles emitted from radon and thoron gas, and the detection efficiency and the crosstalk factor of 218Po/216Po are determined by Monte Carlo simulation. Measurement results have been compared with AlphaGUARD DF2000 in pure radon and thoron environments, respectively. Results show that the measurement results of the devices and the reference monitor agree well with each other, with an average relative deviation of 0.48% for radon gas from about 3300 Bq/m3 to 38 kBq/m3 and -3.25% for thoron gas from about 25 kBq/m3 to 70 kBq/m3. Uncertainty assessment has also been done, and a relative system uncertainty of radon is about 6.8%, while that of thoron is nearly 7.3%.

Estimating Radon Excess Lung Cancer at the Babylon Cement Plant in Iraq

In this work, radon excess lung cancer (ELC) was estimated for 14 soil samples from the Babylon cement plant in Iraq. A CR-39 nuclear track detector was used to measure uranium and radon (222Rn) concentrations in the soil samples. The uranium concentration varied from 0.008 to 0.05 ppm, with a mean value of 0.025 ± 0.013 ppm. The radon concentration was found to be between 31 and 92 Bq/m3, with a mean value of 56.72 and a standard division of 17.29. The radon ELC per million persons per year has a mean value of 863 (463.81–12,082.8) and a standard division of 261.65. The annual effective dose, E (mSv/y), ranged from 0.77 to 2.32, with a mean value of 1.44 and a standard division of 0.44.

Radon Equilibrium Equivalent Concentration Uncertainty of Calibration System With Alpha Self-Absorption Consideration

The measurement of radon decay products level in dwellings or working places separately is not preferable. The estimation of radon equivalent equilibrium concentration (EECRn) is more simple and quick technique. In this work, the uncertainty of calibration system for EECRn measurements will present and the reduction will be suggesting. The calibration system for EECRn measurements was presented and described in previous work with gamma spectrometer as a reference measuring device. The influence of alpha particles absorption in filters materials and filter efficiency taken into account. The measurements of EECRn by gamma spectrometry and improved alpha radiometry are in good agreement and the systematic shift between average values is observed and resolved. The total standard uncertainty of EECRn measurements with gamma spectroscopy is 3.8%. About 71% of this total uncertainty value is related to the uncertainty of the count rate at full absorption peak with gamma spectroscopy. If the time between the end of sampling and gamma spectroscopy measurements reduced to 2000s not 4000 s, this value will reduce to 1.6% and the total standard uncertainty of EECRn will be 2.6%.

Recent Progress in Radon Metrology at IFIN-HH, Romania

The practical implementation of the European Council Directive no. 2013/59/EURATOM in Romania requires reliable indoor measurements of the radon (222Rn) activity concentration in air. In Romania, several Testing Laboratories were designated for radon activity and/or radon activity concentration in air measurements by the Romanian National Commission for Nuclear Activities Control (CNCAN). The calibration of the instruments used for indoor radon activity concentration measurements is very important. IFIN-HH, through its Ionizing Radiation Metrology Laboratory (LMRI), performed advanced research in the field of radon metrology, using radon standard sources prepared by LMRI, its radon chamber facility and a new reference radon monitor. The most recent results are described in this article. The radon chamber facility from IFIN-HH was technically improved, and new equipment and methods were set up and tested in order to provide new calibration services for customers. Additionally, calibration of the radon monitors was performed, as well as of the systems with solid-state nuclear track detectors, used for radon in air activity concentration measurements. IFIN-HH/LMRI obtained the CNCAN designation as Calibration Laboratory for installations measuring the radon activity concentration in air.

Estimation of radon excess lung cancer near some dumpsites in, Lagos, Nigeria

Generally, in Nigeria dumpsites are open and elevate the pollution by increasing the total environment contamination level. This affects not only the site of dumpsites but also the surrounding buildings and area. In the present work, indoor radon activity concentration is tested inside some buildings in the vicinity of dumpsites in Lagos, Nigeria. A passive technique with CR-39 detectors is used. Different buildings around different eight dumpsites were chosen. Radon concentration had ranged from 16.00 ± 3 to 931.00 ± 186 Bqm^-3 in the dumpsites. With Mean concentrations range from 120 ± 24 at OKE-ODO to 334 ± 67, at Solus-4 respectively. The present results explain that 63% of the radon activity concentration in indoor air around the selected dumpsites at Lagos city in Nigeria is below the allowed limit from ICRP 200 Bq m-3 while 37% is more than this limit. Based on the measured radon concentration, the annual effective dose and cancer risk are evaluated. The range of ELC is from 242 to 14086 with mean value 3114 ± 1111.

Radon decay products equilibrium at different aerosol concentrations

The influence of aerosol particle concentration on the activity of short-lived radon decay products (RPDs) was investigated inside a standard radon box. The ²¹⁸Po:²¹⁴Pb:²¹⁴Bi activity ratio was determined for unattached and attached fractions of radon decay products at different aerosol concentrations. For the unattached fraction, this ratio was 1:0.31:0.06, while for the attached aerosol fraction the activity ratio was 1:1.4:0.91 at a low aerosol concentration (2000 cm^-3) and with the unattached fraction f_p = 0.45. In this case, there was no additional aerosol in the standard radon box and the equilibrium shift ratio for the total activity (attached and unattached) was 1:0.55:0.27 for ²¹⁸Po:²¹⁴Pb:²¹⁴Bi. When the aerosol was injected, the unattached fraction nearly disappeared at a high aerosol concentration (80000-90000 cm^-3). The equilibrium shift ratio for the total activity at a high aerosol concentration was 1:2:1.5 for ²¹⁸Po:²¹⁴Pb:²¹⁴Bi. This ratio was the same for the attached fraction. For no more than 0.01 of the unattached fractions, this ratio was 1:0.85:0.7. Radioactive equilibrium factors and unattached fractions were also determined at different aerosol particles concentrations. A negative correlation between unattached fraction and the radioactive equilibrium factor, as well as a positive correlation coefficient between the radioactive equilibrium factor and aerosol particle concentration in a standard radon box, has been determined.

The experimental study on the emanation power of a flow-through thoron source made from incandescent gas mantles

To improve the quality of the calibration of thoron concentration activity measurement, an experimental study on the emanation power of a flow-through thoron source based on incandescent gas mantles was carried out in this paper. The thoron activity concentrations of the outflowed air from the flow-through source were measured using RAD7, and the quantitative relationship between thoron concentrations and flowrates was studied through theoretical analysis, and the thoron emanation powers were obtained from the fitting of the relationship above. Results show that the thoron concentration decreased with the increasing flowrate in the gas path, and the thoron emanation powers of three batches of gas mantles obtained by fitting were 1.33% ± 0.17%, 0.77% ± 0.10% and 0.57% ± 0.07% respectively in low humidity condition. Those results were checked using the gamma spectroscopy method, and were consistent within the error range.