Malaysian Journal of Analytical Sciences Vol 18 No 3 (2014): 618 - 628

 

 

 

CONSTRUCTION OF RADON CHAMBER FOR DETERMINATION OF RADON EMANATION USING CONTINUOUS RADON MONITOR

 

(Pembinaan Kebuk Radon untuk Penentuan Emanasi Radon Menggunakan Alat Permonitoran Radon)

 

Norafatin Khalid*, Amran Ab Majid, Redzuwan Yahaya, Muhammad Samudi Yasir, Faizal Mohamed

 

School of Applied Physics, Faculty of Science and Technology,

Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia

 

*Corresponding author: nora.fatin@ymail.com

 

 

Abstract

An airtight chamber was designed and constructed in order to determine the emanation and the activity concentration of radon and to optimize measurement of radon emanation in terms of temperature, pressure and humidity. In this study, an airtight chamber in size of 0.50 m (width) x 0.40 m (depth) x 0.35 m (height) with total chamber volume of about 0.07 m³ was built by using a perspex material with 6 x 10^-3 m of thicknesses. A Continuous Radon Monitor (CRM) Sun Nuclear model 1029 was used to measure the emanation of radon in the chamber. This homemade chamber has a rectangular opening with two key systems to insert and remove samples and continuous radon monitor to prevent any of disturbances to the flow of air in the chamber.An efficiency and leakage tests were carried out before radon activity was measured. Xenotime mineral was inserted into the chamber as a source of radon (²²²Rn). Radon measurements were done for each hour over 96 hours counting time. The results indicated that the background of radon concentration in an empty chamber was 21.0 ± 4.8 Bq m^-3. The usage of 0.15 kg, 0.25 kg and 0.50 kg of xenotime mineral recorded 249.6 ± 119.1 Bq m^-3, 400.0 ± 187.6 Bq m^-3, 2236.6 ± 213.8 Bq m^-3 of radon activities respectively.The effect of volume of the homemade radon chamber, the mass of xenotime, temperature, pressure and humidity to the radon emanation will be discussed in this paper.

 

Keywords: radon, radon monitor, radon chamber, xenotime

 

Abstrak

Kebuk kedap udara telah direka dan dibina bagi menentukan emanasi dan kepekatan aktiviti  radon  dan mengoptimumkan pengukuran emanasi radon dari sudut suhu, tekanan dan kelembapan. Dalam kajian ini, kebuk kedap udara bersaiz 0.5 m (lebar) x 0.4 m (panjang) x 0.35 m (tinggi) dengan jumlah isipadu kebuk 0.07 m³ telah dibina menggunakan bahan perspek dengan ketebalan 6 x 10^-3 m. Alat permonitoran radon secara berterusan (CRM) model Sun Nuklear 1029 digunakan untuk mengukur emanasi gas radon di dalam kebuk. Kebuk yang direka bina ini mempunyai pembukaan bersaiz segi empat tepat dengan dua system kekunci untuk memasukkan dan mengeluarkan sampel dan juga alat permonitoran radon bagi menghalang berlaku gangguan terhadap aliran udara di dalam kebuk tersebut. Ujian ketahanan dan kebocoran kebuk dilakukan sebelum pengukuran radon dijalankan. Mineral xenotim dimasukkan ke dalam kebuk sebagai sumber  radon, (²²²Rn). Pengukuran  radon  telah dilakukan bagi setiap jam untuk selama 96 jam masa pembilangan. Hasil kajian menunjukkan kepekatan radon latar belakang dalam kebuk kosong adalah 21.0 ± 4.8 Bq m^-3. Penggunaan sumber radon  xenotim dengan jisim 0.15 kg, 0.25 kg, 0.5 kg masing-masing mencatatkan bacaan kepekatan radon iaitu 249.6 ± 119.1 Bq m^-3, 400.0 ± 187.6 Bq m^-3, 2236.6 ± 213.8 Bq m^-3. Perubahan kadar emanasi radon terhadap isipadu kebuk radon, jisim xenotim, suhu, tekanan dan kelembapan menggunakan kebuk buatan sendiri ini dibincangkan dalam kertas ini.

 

Kata kunci: radon, permonitoran radon, kebuk radon, xenotim

 

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