Routine works for radiation safety in the Ring Cyclotron Facility

Abstract

The radiation safety control system has worked steadily during 1998 so as to enable to execute the radiation monitoring service continuously and automatically. From the accumulated data of leakage neutrons, the radiation level in the controlled area was found much less than the recommended dose limit. Leakage of either gamma rays or neutrons was not detected in the environmental monitors installed outside the building during this reported period. The radiation level at the boundary of the accelerator facility was evaluated. The leakage was recorded in a monitor installed in the ground floor computer room just above the bending magnet to guide the beams. The radiation level was found much less than the recommended dose limit. Two Hand-Foot-Cloth (HFC) monitors with beta (gamma) detector was used at the entrance of the controlled area. When one of the HFC monitors was out of order, many people could not get out smoothly from the controlled area. To improve the situation, a new HFC monitor which can detect alpha rays as well as beta (gamma) rays has been installed in February 1998.

放射線安全管理システムは1998年中順調に作動し、連続的かつ自動的な放射線監視業務の遂行が可能であった。漏れ中性子についての蓄積データから、管理区域内の放射線レベルは基準線量限界よりずっと低い値を示した。この期間中建物の外に設置した環境モニタは、ガンマ線も中性子の漏れも検出しなかった。加速器施設の境界で放射線レベルを評価した。ビームを誘導する偏向磁石のすぐ上の1階計算機室に設置したモニタで漏れを記録した。放射線レベルは基準線量限界よりずっと低かった。β(γ)検出器をもつ2つの手足衣類モニタを管理区域の入口に使用した。その1つが故障のときは、人々が管理区域から出ることが円滑に行われなかったので、状況の改善のために、β(γ)線とともにα線も検出できる新たな手足衣類モニタを1998年2月に設置した。