The most comprehensive study of the radiation that penetrates aeroplanes is set to throw light on the risks to passengers and crew.
Virgin aeroplanes will be used to carry the detectors, with the aim of having at least one in the air at all times for the next three years. Data from the detectors will identify the intensity of radiation coming from deep space, the Sun and the Earth鈥檚 magnetosphere.
The start of the study coincides with the 鈥渟olar maximum鈥� 鈥� the most intense period in the Sun鈥檚 11-year cycle of activity. The scientists think radioactive particles from the Sun may make a bigger contribution to radiation inside aircraft than is usually assumed.
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Bob Bentley of the Mullard Space Science Laboratory in Dorking, UK says cosmic radiation is also important. 鈥淲e know that cosmic radiation at aircraft altitudes is several orders of magnitude more intense than that at ground level, because there is less protection from our atmosphere.鈥�
X-ray dose
Some studies have found that air crews are more likely to develop breast, prostate, colon, rectal and brain cancers. 鈥淏ut the extent and nature of the risk to aircraft and crew is poorly understood,鈥� says Bentley.
The radiation dose from a transatlantic flight is similar to that from a chest X-ray. Air crew are exposed to more radiation in a year than nuclear power plant workers. Frequent flyers may also be at risk.
鈥淔or frequent fliers and aircrew the accumulated dose of radiation may be significant,鈥� says Robert Hunter of the Civil Aviation Authority, which is taking part in the project.
The project鈥檚 main aim is to work out the relative importance of the three sources of radiation. While knowing overall levels of radiation exposure is vital for judging health risks, the type of radiation is also important.
Solar flares
鈥淥ur detectors are the most sophisticated out there,鈥� says Andrew Coates of the Mullard Space Science lab. 鈥淭hey let us determine the composition of the particles. We suspect that most are cosmic rays but we expect the radioactive particles to be significantly enhanced at times of heightened solar activity.鈥�
The solar maximum is due any time between mid-October and early next year, says Coates. The number of solar flares is highest at the solar maximum. These violent outbursts produce high energy radioactive particles.
鈥淧revious studies of radiation penetrating aircraft have been very sporadic. By having a detector in the air all the time we shouldn鈥檛 miss an event that goes off,鈥� Coates says.
