Radon exhalation rates corrected for leakage and back diffusion – Evaluation of radon chambers and radon sources with application to ceramic tile

Abstract

Leakage rateBack diffusion rate Radon exhalation rate Radon chambers a b s t r a c tThe natural radon decay, leakage and back diffusion are the main removal processes of radon from its container. Ignoring these processes leads to underestimate the measured value of radon related parameters like exhalation rate and radium content. This work is aimed to evaluate two different radon chambers through determining their leakage rate l v and evaluation of radon source by determine its back diffusion rate l b inside the evaluated radon chambers as well as a small sealed cup. Two different methods are adapted for measuring both the leakage rate and the back diffusion rate. The leakage rate can be determined from the initial slope of the radon decay curve or from the exponential fitting of the whole decay curve. This can be achieved if a continuous monitoring of radon concentration inside the chamber is available. Also, the back diffusion rate is measured by sealing the radon source in the chamber and used the initial slope of the buildup curve to determine l b and therefore the exhalation rate of the source. This method was compared with simple equation for l b based on the ratio of the source to the chamber volume. The obtained results are applied to ceramic tile as an important radon source in homes. The measurement is targeted the ceramic glaze before and after firing as well as the obtained tile after adhere the glaze on the tile main body. Also, six different tile brands from Egyptian market are subjected to the study for comparison.

Investigation of Radium Contents and Radon Exhalation Rates in Soil Samples in Menge District, Ethiopia

“…The research data would have been analyzed by wellestablished mathematical expressions. The radon concentrations and radium contents of the soil samples have calculated by using the relations [18][19][20][21][22][23][24]:…”

“…Where K (=1.075 tracks cm -2 day -1 (Bqm -3 ) -1 ) is the correction or calibration factor of the detector [2,15], is the surface density (tracks cm -2 ), h is the distance between the top of the container and the top of soil samples (m), A is the area of the can (m 2 ), M is the mass of the soil sample (kg), T e is the effective equilibrium time which is related with the actual equilibrium time (exposure time) T, V is the volume of the Can, C Rn is the radon concentration (Bqm -3 ) and decay constant for 222 Rn with the relation. The general formula to calculate the effective equilibrium time is [18][19][20][21][22][23][24]:…”

KEHILANGAN H2O SELAMA REAKSI PELINDIAN MINERAL ZIRCON DENGAN NaOH DI DALAM FURNACE

“…Demikian pula Abdel-Rehim [20] bahwa temperatur dan waktu kontak akan mempercepat terhadap reaksi pembentukan senyawa zirkonium zirkonat yang reaksi (1). Sementara Lubbe [16] merubah perbandingan mole ZrSiO4/NaOH (1:6), sehingga dikeluarkan produk H2O yang menguap dan keluar ke udara bebas dan membawa gas radon yang beracun [8]. Pada Gambar 3 berikut dapat disajikan hasil prediksi kehilangan H2O melalui hubungan antara waktu kontak dengan kehilangan H2O di setiap perubahan temperatur pada perbandingan mole rasio ZrSiO4/NaOH (1:2).…”

“…Secara alami kandungan U+Th di dalam mineral zirkon masing-masing akan meluruh menjadi anak luruhnya. Salah satu anak luruh U-238 adalah Rn-222 sedangkan Th-232 berupa Rn-220, dan masing-masing isotop tersebut berbentuk gas [8]. Walaupun berumur paruh pendek, dengan bentuk gas Rn-222 dan Rn-220 sangat mudah larut di dalam H2O [9][10][11].…”

“…Aplikasi pada reaksi 1 tersebut dilakukan di dalam furnace pada suhu 600 o C [15,16] atau 700 o C [17] akan dihasilkan H2O yang menjadi uap dan sebagai carrier gas radon ke udara [8]. Berdasarkandata kelarutan gas radon ke dalam H2O yang terlepas dari mineral zirkon [12],serta dampaknya terkena kanker paru bagi pekerja radiasi menarik untuk diteliti [13].…”