Earticle

초록

영어

Background: The concrete walls inside the vaults of cyclotron facilities are activated by neutrons emitted by the targets during radioisotope production. Reducing the amount of radioactive waste created in such facilities is very important in case they are decommissioned. Thus, we proposed a strategy of reducing the neutron activation of the concrete walls in cyclotrons during operation. Materials and Methods: A polyethylene plate and B-doped Al sheet (30 wt% of B and 2.5 mm in thickness) were placed in front of the wall in the cyclotron room of a radioisotope production facility for pharmaceutical use. The target was Xe gas, and a Cu block was utilized for proton dumping. The irradiation time, proton energy, and beam current were 8 hours, 30 MeV, and 125 μA, respectively. To determine a suitable thickness for the polyethylene plate set in front of the B-doped Al sheet, the neutron-reducing effects achieved by inserting such sheets at several depths within polyethylene plate stacks were evaluated. The neutron fluence was monitored using an activation detector and 20-g on de Au foil samples with and without 0.5-mm-thick Cd foil. Each Au foil sample was pasted onto the center of a polyethylene plate and B-doped Al sheet, and the absolute activity of one Au foil sample was measured as a standard using a Ge detector. The resulting relative activities were obtained by calculating the ratio of the photostimulated luminescence of each foil sample to that of the standard Au foil. Results and Discussion: When the combination of a 4-cm-thick polyethylene plate and Bdoped Al sheet was employed, the thermal neutron rate was reduced by 78%. Conclusion: The combination of a 4-cm-thick polyethylene plate and B-doped Al sheet effectively reduced the neutron activation of the investigated concrete wall.

목차

ABSTRACT
 Introduction
 Materials and Methods
  1. Materials
  2. Irradiation setup
  3. Activity measurement
 Results and Discussion
 Conclusion
 References

키워드

저자

• Masaaki Kumagai [ ATOX Co., Ltd, Tokyo, Japan ]
• Kohsuke Sodeyama [ ATOX Co., Ltd, Tokyo, Japan ]
• Yukio Sakamoto [ ATOX Co., Ltd, Tokyo, Japan ]
• Akihiro Toyoda [ Radiation Science Center, High Energy Accelerator Research Organization, Tsukuba, Japan ]
• Hiroshi Matsumura [ Radiation Science Center, High Energy Accelerator Research Organization, Tsukuba, Japan ]
• Takayoshi Ebara [ ATOX Co., Ltd, Tokyo, Japan ]
• Taichi Yamashita [ ATOX Co., Ltd, Tokyo, Japan ]
• Kazuyoshi Masumoto [ Radiation Science Center, High Energy Accelerator Research Organization, Tsukuba, Japan ] Corresponding author

참고문헌

발행기관

간행물

표지보기 관심저널 등록

• 간행물명

  방사선방어학회지 [Journal of Radiation Protection and Research]

• 간기

  계간

• pISSN

  2508-1888

• 수록기간

  1976~2026

• 등재여부

  KCI 등재,SCOPUS

• 십진분류

  KDC 559 DDC 629