Sains Malaysiana 49(3)(2020): 683-691

http://dx.doi.org/10.17576/jsm-2020-4903-23

 

Kajian terhadap Tanah Liat Bentonit dan Kaolin sebagai Perisai Sinaran

(Study on Clay Bentonite and Kaoline as Shielding Material)

 

NUR FATIN NABILAH ZUHAIRI1,2, NORSYAHIDAH MOHD HIDZIR1,2*, AZUHAR RIPIN3, MOHD IDZAT IDRIS1,2 & NUR AIN MOHD RADZALI1,2

1Pusat Penyelidikan Teknologi Nuklear, Fakulti Sains dan Teknologi, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor Darul Ehsan, Malaysia

2Jabatan Fizik Gunaan, Fakulti Sains dan Teknologi, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor Darul Ehsan, Malaysia

3Kumpulan Fizik Perubatan, Agensi Nuklear Malaysia, 43000 Kajang, Selangor Darul Ehsan, Malaysia

 

Diserahkan: 7 Oktober 2019/Diterima: 3 Disember 2019

 

ABSTRAK

Plumbum (Pb) merupakan perisai sinaran yang utama bagi mengurangkan dedahan sinaran gama. Pb mempunyai bilangan atom dan ketumpatan yang tinggi. Walau bagaimanapun, Pb adalah bersifat toksik, sangat berat serta mempunyai tahap penyerapan neutron yang sangat rendah. Justeru, perisai sinaran dengan ciri-ciri yang ideal seperti ringan dan berkeupayaan tinggi dalam menghalang sinaran sedang giat diterokai. Antara perisai yang sedang dikaji pada masa kini ialah yang diperbuat daripada tanah liat. Tanah liat mempunyai ciri-ciri takat lebur yang tinggi, kestabilan termokimia dan kekuatan mekanik pada suhu yang tinggi. Ciri-ciri ini menjadikan tanah liat berpotensi sebagai perisai sinaran. Justeru, kajian ini dijalankan bagi menentukan perincian unsur, nilai pekali pengecilan serta perbandingan nilai ketebalan kesetaraan plumbum untuk tanah liat (iaitu bentonit dan kaolin). Perincian unsur tanah liat ditentukan daripada analisis pembelauan sinar-X (XRD) dan mikroskop imbasan medan elektron (FESEM). Ujian pembakaran tanah liat dilakukan pada suhu ~1000 oC bagi melihat sebarang perubahan terhadap sifat fizikal dan kimia tanah liat. Sementara itu, ujian bagi penentuan pekali pengecilan dilakukan menggunakan sumber sinaran gama dan sinar-X. Hasil analisis menunjukkan tiada perubahan yang ketara bagi sifat kimia dan fizikal tanah liat selepas ujian pembakaran. Berdasarkan pekali pengecilan, tanah liat jenis bentonit mempunyai nilai pekali pengecilan yang lebih tinggi berbanding kaolin dengan hampir 90% pengurangan dos berjaya diperoleh. Akhir sekali, analisis ketebalan kesetaraan plumbum menunjukkan nilai kesetaraan bagi bentonit adalah tinggi berbanding kaolin. Kesimpulannya, tanah liat bentonit menunjukkan keupayaan pengurangan dos yang tinggi untuk digunakan sebagai perisai sinaran.

 

Kata kunci: Bentonit; kaolin; perisai sinaran; tanah liat; sinar-X

 

ABSTRACT

Lead (Pb) is a main shielding material for gamma radiation. Lead has a high number of atoms and density. However, lead is toxic, very heavy and has low neutron absorption capacity. Therefore, a shielding material with ideal characteristics such as lightweight and high radiation attenuation are actively being explored. Among the shielding material that currently being studied are those made of clay. Clay has high melting point, thermochemical stability and high mechanical strength. These features make the clay potentially be used as a shielding material. Therefore, this study was carried out to determine the element presence in the clay, the attenuation coefficient and the comparison of lead-equivalent thickness values for clay (i.e. bentonite and kaoline). The details of the clay elements were determined by using X-ray diffraction (XRD) analysis and field emission scanning electron microscopy (FESEM). Clay combustion tests were conducted at ~ 1000 oC in order to see any changes in the physical and chemical properties. Meanwhile, the test for the determination of the attenuation coefficient was performed using a source of gamma and X-ray. The results showed that no significant changes in the chemical and physical properties of the clay after the combustion test. Based on the attenuation coefficient, bentonite has a higher attenuation coefficient compared to kaoline with almost 90% of dose reduction achieved. Finally, lead equilibrium thickness analysis showed that bentonite's equilibrium value was higher than kaoline. In conclusion, bentonite shows high reduction of dose capability to be used as a radiation shielding.

 

Keywords: Bentonite; clays; kaoline; shielding; X-rays

 

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*Pengarang untuk surat-menyurat; email: syahidah@ukm.edu.my

 

 

 

 

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