医用小型回旋加速器放射性污染初步分析

Radioactive contamination of small-scale medical cyclotron

回旋加速器 ,高能强质子束流 ,轰击靶材料产生所需放射性核素同时产生液态、固态、气态放射性物质 ,形成放射性污染。液态放射性污染主要指加速器冷却循环水受中子照射被活化形成放射性物质 ;固体放射性污染为热室工作箱内的模板 ,退役加速器离子源、准直器和靶周围被活化的器件及与放射性制剂分装、注射相关的用品 ;放射性气态污染 ,主要指中子使空气活化产生核素11C、13N、15O、41Ar,空气中其它成份被中子活化产额低 ,多为气溶胶状态 ;另外放射性表面污染主要指加速器厅内被活化的固体器件 ,冷却水破裂或放射性药物意外污染 ,有关传递通道和贮源容器的表面放射性污染。

In the cyclotron,a strong beam current of proton with high-energy hits the target materials not only to produce the needed radioactive nuclide, but also to produce liquid,solid and gaseous radioactive substances forming radioactive contamination.The liquid radioactive contamination comes from the radioactive substances produced by the circulatory cooled water activated after neutron radiation;the solid radioactive contamination comes from the match plate in the hot working chamber,the collimation equipment,the devices activated around the target and something relevant with radioactive agents;and radioactive gaseous contamination comes from the nudide 11C,13N,15O,41Ar produced by air activation.Other radioactive contents in the air are the low amount of that activated by neutron,which are mostly in gas sol state.The radioactive surface contamination refers to the incidental contamination resulting from the solid devices activated in the accelerator hall,broken coled water pipes and radioactive drugs,including radioactive surface contamination of transmitting passages and source containers.