MadSci Network: Engineering

Re: Will airport XRays harm digital camera circuitry or memory

Date: Wed Aug 30 06:11:57 2006
Posted By: Gareth Evans, Industrial R&D practitioner and manager ( retired )
Area of science: Engineering
ID: 1155996806.Eg

Hi Mark, thanks for your question. You asked whether airport x-rays will harm digital camera circuitry or memory.

We used to be told that x-ray equipment at airports didn't "harm" photographic film. That advice has changed for a number of reasons. Films in common use are now "faster", that is more responsive to light and x-rays. Also as security at airports has become more and more important the equipment and x-ray scanning practice has changed. Sometimes film can be completely ruined.

The equipment giving the largest radiation dosages is usually used for checked-in baggage. The x-rays have to penetrate larger packages and cases than carry-on baggage. They are also used in situations where it is easier to keep people away from the equipment so larger doses can be applied without harming staff or passengers. Some equipment will increase exposure if an object is opaque to x-rays. For example a roll of cine-film stock would normally appear opaque to equipment set up to scan typical baggage and would consequently be damaged and probably ruined, a real pain if the film was exposed but undeveloped!

Your question was of course not about film but digital cameras and memory. The picture here is also not entirely simple. It is often said that digital cameras are immune to x-rays but as with a lot of issues it is more a matter of degree. If anything can be imaged using x-rays it is because it will absorb x-rays. That process involves the conversion of the energy of the x-rays to, initially, many high-speed electrons, usually capable of generating other high energy electrons all of which can potentially cause localised damage. The problem is a recognised one. For example this link is to a paper describing methods of compensating for such damage: tp=&arnumber=816438&isnum ber=17670 So there is no doubt that a camera will be affected but the question is "does it matter´┐Ż". In other words is the damage likely to be noticeable.

Despite the concerns I might have stirred up I don't believe there is a serious problem. All radiation concerns must be seen in the context of the inevitable background radiation we live in. This comes from radioactive material in our environment, from for example, potassium and radon, and cosmic rays. Infrequent exposure to low-dose x-ray imaging equipment probably not add significantly to the exposure from background radiation over a long period of time. It is therefore unlikely that you will see any evidence of damage to digital cameras or memory from a few exposures.

Remember, though, that x-ray damage accumulates and the high levels of exposure by other equipment than carry-on baggage scanners could result in noticeable defects. Finally, the damage to sensors, memory and other circuitry is likely to be much greater if the camera is switched on. The second rule is therefore switch the camera off. What was the first rule? Try to avoid x-ray examination by offering hand examination, just to be on the safe side.

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