방사선의학 웹진

바로가기  >

이달의 연구자 바로가기 Click!

Abstract
In this study, the lithium target thickness and a beam-shaping assembly (BSA) system were designed using Monte Carlo N-Particle version 6.2 for a 2.4 MeV, 15 mA proton accelerator-based neutron source. The BSA components consist of lead (Pb), magnesium fluoride (MgF2), boron carbide (B4C), and tungsten (W) used for the reflector, moderator, and collimator, respectively. The specifications (area and thickness) of each BSA part were varied to analyze the characteristics of neutrons passing through the BSA. The system's performance was evaluated based on various indicators, including the epithermal neutron flux, ratio of epithermal to thermal neutrons, fast neutron contamination, gamma contamination, and neutron current to flux ratio. Monte Carlo simulations were conducted to determine BSA specifications that satisfied the neutron beam requirements recommended by the International Atomic Energy Agency. The lithium target thickness was determined to be 90 μm, and BSA's performance was confirmed under various conditions. For the specifications that yielded the highest epithermal neutron flux, the epithermal neutron flux at the BSA exit was 8.89 × 108 cm-2 s-1, the ratio of epithermal neutrons to thermal neutrons was 425.54, the neutron current-to-flux ratio was 0.7, and the dose contaminations due to fast neutrons and gamma rays were 1.20 × 10-13 Gy cm2 and 1.91 × 10-13 Gy cm2, respectively.

설계 한 BSA 모습 및 출구방향에서의 중성자 및 감마선 스펙트럼입니다. 여러 디자인을 고려 한 결과 IAEA 권고를 충족시키는 디자인을 결정할 수 있었습니다. IAEA 권고와의 비교는 다음과 같습니다.

Affiliations

Minho Kim 1, Hyounggun Lee 2, MinSeok Park 2, Bong Hwan Hong 2, Chawon Park 2, Kyeong Min Kim 2, Seungwoo Park 2, Won Taek Hwang 2, Ho Namgoong 2
1Korea Institute of Radiological and Medical Sciences, Seoul, 01812, South Korea. Electronic address: cleverkmh@kirams.re.kr.
2Korea Institute of Radiological and Medical Sciences, Seoul, 01812, South Korea.