宇宙辐射来自银河系,与地球大气层作用生成次级辐射,由电离成分(μ介子、快速点子和γ线等)和中子组成。民航机组人员在飞行中会受到这种高能量的次级辐射的照射。过去,人们对它的危害认识不足,随着科技的发展,这个问题已提到日程上来了。60年代,在研制超音速飞机时,就预计到宇宙辐射可能成为有影响的航空环境之一。飞行实测发现:在北大西洋航线,飞行高度20～22千米,虽然往返一次飞行时间仅7个多小时,但机组人员所受宇宙辐射剂量却高达2.4毫希沃特(mSv)。这意味着:飞行20个往返(150飞行小时,即占全年额定飞行小时的1/4)就 Cosmic radiation comes from the Milky Way and generates secondary radiation from the Earth’s atmosphere. It consists of ionizing components (muons, fast radicals, gamma rays, etc.) and neutrons. Civil aviation crew members are exposed to such high-energy secondary radiation during flight. In the past, people did not fully understand the dangers it posed. With the development of science and technology, the issue has been brought to the agenda. In the 1960s, when developing supersonic aircraft, it was anticipated that cosmic radiation could become one of the influential aeronautical environments. The flight survey found that on the North Atlantic route, the flight altitude was 20-22km. Although the round-trip flight time was only over 7 hours, the flight crew suffered as much as 2.4 mSv of cosmic radiation. This means: 20 roundtrips (150 flying hours or 1/4 of the annual flying hours)