Study of Thermal Neutron Flux and Generated Energy from Linac using CR-39 Detector in Liquid Medium

Kurnia Nur Widyanti, Chomsin S. Widodo, Bunawas Bunawas


Linac surgery is required in radiotherapy activities. However, if Linac operated more than 8 MV can cause additional radiation of neutrons, as well as triggers forming secondary cancer. The study was conducted to determine the distribution of thermal neutron flux and energy responses on the trace. One method to detect neutrons is to use a nuclear trace detector. Measurements were made using a CR-39 detector coated with a Boron radiator. A number of detectors were placed on the surface of the sphere and entered into a 30×30×30 cm3 fantom. Irradiation is done by placing fantom under Linac gantry with 100cm SSD distance. After irradiation, then etching. The results of the measurements showed that the distribution of thermal neutron fluxes spread in all directions. Linac 10 MV neutron flux value varies, starting at 0° of 1,637×103 n/cm2.s and decrease at 135°of 1.285×103 n/cm2s. The highest Linac 15 MV at detector position 0° of 10.723x104 n/cm2.s and decreased at 135° of 5.142x104 n/cm2s. This proves that the farther from the source the less the thermal neutron flux value due to the collision process. While Linac 10 MV and 15 MV produce range of diameter ranging from 8.21-16.75 (μm) and 9.21-17.45 (μm), with energy response value 0.5-3.5 MeV. The larger the energy response, the smaller the diameter and vice versa, this is due to the effect of penetration on the depth of the distance resulting in smaller track.


Linac, neutron, thermal neutron flux

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Diyona, F., Milvita, D., Herlinda, S., Yudi, K. dan Sandy, P. (2016) Analisis Pengaruh Sudut Penyinaran terhadap Dosis Permukaan Fantom Berkas Radiasi Gamma Co-60 pada Pesawat Radioterapi. Jurnal Fisika Unand, 5, 131–5.

Vukovic, B., Faj, D., Poje, M., Varga, M., Radolic, V., Miklavcic, I. et al. (2010) A neutron track etch detector for electron linear accelerators in radiotherapy. Radiology and oncology, 44, 62–6.

Firmansyah, M.A. (2014) Pengukuran neutron Cepat di ruang Linac Medis Menggunakan Detektor Jejak Nuklir CR-39. Universitas Brawijaya.

Latifah, R., Noor, J.A.E. dan Bunawas, B. (2013) Thermal Neutron Flux Measurements at Room Treatment LINAC iX 15 MV. Natural B, 2, 184–90.

Eaton, B.R., MacDonald, S.M., Yock, T.I. dan Tarbell, N.J. (2015) Secondary Malignancy Risk Following Proton Radiation Therapy. Frontiers in oncology, 5, 261.

Septiani, D.F. (2015) Perkiraan Dosis ekuivalen Neutron Cepat pada Pasien Radioterapi Linac 15 MV. Universitas Brawijaya.

Hentihu, F.K. (2014) Perkiraan Dosis Ekuivalen Neutron Termal Pasien Radioterapi Linac 15 MV. Universitas Brawijaya.

Forbes, G.B. (1987) Human Body Composition. Springer New York, New York, NY.

Sánchez-Doblado, F., Domingo, C., Gómez, F., Sánchez-Nieto, B., Muñiz, J.L., García-Fusté, M.J. et al. (2012) Estimation of neutron-equivalent dose in organs of patients undergoing radiotherapy by the use of a novel online digital detector. Physics in medicine and biology, 57, 6167–91.

Akhadi, M. (2000) Dasar-Dasar Proteksi Radiasi. PT. Rineka Cipta, Jakarta.

Sutarman, Nirwani, L., Emlinarti dan Warsona, A. (2005) Penentuan Konsentrasi Gas Radon dan Thoron Menggunakan Detektor Film Lr-115 di DKI dan Sekitarnya. Prosiding PPI – PDIPTN 12 Juli 2005, Puslitbang Teknologi Maju - BATAN, Yogyakarta.

Hasan, H.I., Hussein, A.K. dan Kheder, R.B. (2013) Angular Response of Nuclear Track Detector CR-39 for Alpha Particles with Different Energies. Pure Applied Science, 1, 22–7.

Law, Y.L., Nikezic, D. dan Yu, K.N. (2008) Optical appearance of alpha-particle tracks in CR-39 SSNTDs. Radiation Measurements, Elsevier Ltd. 43, 128–31.

Immè, G., Morelli, D., Aranzulla, M., Catalano, R. dan Mangano, G. (2013) Nuclear track detector characterization for alpha-particle spectroscopy. Radiation Measurements, 50, 253–7.

Nikezic, D. dan Yu, K.N. (2008) Analyses of light scattered from etched alpha-particle tracks in PADC. Radiation Measurements, 43, 1417–22.


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