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Sains Malaysiana 48(1)(2019): 191–197
http://dx.doi.org/10.17576/jsm-2019-4801-22
Measurement
of Neutron Flux and Gamma Dose Rate Distribution Inside a Water
Phantom for Boron Neutron Capture Therapy Study at Dalat Research
Reactor (Pengukuran
Neutron Fluks dan Pengagihan Kadar Dos Gama dalam Fantom Air untuk
Kajian Terapi Boron Neutron Tertawan di Reaktor Penyelidikan Dalat)
TRINH THI TU ANH1*, PHAM DANG QUYET1, MAI NGUYEN TRONG NHAN2 & PHAM NGOC SON3
1Dalat University, 01
Phu Dong Thien Vuong, Dalat, Vietnam
2Ulsan National
Institute of Science and Technology, Ulsan 44919, Republic of Korea
3Nuclear Research
Institute, 01 Phu Dong Thien Vuong, Dalat, Vietnam
Diserahkan: 7 Jun 2018/Diterima: 7 September 2018
ABSTRACT
Exposure dose rate to the tumor and surrounding cells during
neutron beam irradiation in Boron Neutron Capture Therapy (BNCT)
comes not only from heavy charged particles produced from the 10B(n,α)7Li
nuclear reaction, but also from neutron-induced reactions with other biological
elements in living tissue, as well as from gamma rays leaked from the reactor
core. At Dalat Research Reactor, Vietnam, the neutron and gamma dose rate
distribution inside a water phantom were measured by using activation method
and Thermoluminescent Dosimeter (TLD) detector, respectively.
The results showed that effective thermal neutron dose rate along the center
line of the water phantom had a maximum value of 479 mSv h-1 at
1 cm in phantom and then decreases rapidly to 4.87 mSv h-1 at
10 cm. The gamma dose rate along the center line of the water phantom also
reach its maximum of 4.31 mSv h-1 at 1 cm depth and decreases
to 1.16 mSv h-1 at 10 cm position. The maximum biological tumor dose
rate was 1.74 Gy-eq h-1, not high enough to satisfy the
treatment requirement of brain tumors. However, the results of this work are
important in supporting of BNCT study in the upcoming stages at
Dalat Research Reactor.
Keywords: BNCT; dose rate; TLD detector;
thermal neutron flux; water phantom
ABSTRAK
Kadar dos pendedahan kepada tumor dan sel sekitarnya semasa pancaran
sinaran neutron dalam Terapi Boron Neutron Tertawan (BNCT)
datang bukan sahaja daripada zarah berat bercas yang dihasilkan
daripada tindak balas nuklear 10B(n,α)7Li, tetapi juga daripada tindak
balas neutron-teraruh daripada unsur biologi lain dalam tisu hidup,
selain daripada sinar gama yang bocor daripada teras reaktor. Di
Reaktor Penyelidikan Dalat, Vietnam, kadar pengagihan dos neutron
dan gama dalam fantom air diukur masing-masing menggunakan kaedah
pengaktifan dan pengesan Thermoluminescent Dosimeter (TLD). Keputusan menunjukkan bahawa kadar dos haba neutron
yang berkesan sepanjang garis tengah fantom air mempunyai nilai
maksimum 479 mSv h-1
pada 1 cm dalam phantom dan kemudian menurun dengan
pantas kepada 4.87 mSv h-1 pada 10 cm. Kadar dos gama sepanjang garis tengah fantom
air juga mencapai tahap maksimum 4.31 mSv h-1 pada
kedalaman 1 cm dan menurun ke 1.16 mSv h-1 pada kedudukan 10 cm. Kadar
dos maksimum tumor biologi adalah 1.74 Gy-eq h-1 namun
tidak cukup tinggi untuk memenuhi keperluan rawatan tumor otak.
Walau bagaimanapun, keputusan kajian ini adalah penting dalam menyokong
pengajian BNCT
pada peringkat akan datang di Reaktor Penyelidikan
Dalat.
Kata kunci: BNCT;
fantom air; fluks haba neutron; kadar dos; pengesan TLD
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*Pengarang untuk surat-menyurat; email: anhttt@dlu.edu.vn
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