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X-Rays Of A TiBook's Interior
A reader writes: "A fine application of expensive medical equipment: producing neat desktop pictures by taking an x-ray of the guts of a PowerBook G4. Guy Mullins has the details." The actual photos are on a separate site.
I have no real knowledge other than common sense, and since this is /., I would guess the medical imager is weaker since the purpose is to scan people. Whereas the airport is not worried about radiating people, just seeing through laptops and such.Normal bomb/gun/knife stuff.
Most parts of a computer are "immune" to xrays. Meaning that the computer doesn't get damaged by them.
However, CMOS EEPROM cells that are designed using buried gate transistors (which is the most common type of EEPROM these days) can be damaged by xrays. If an xray passes through the buried gate to the channel, it'll ionize a bit of the silicon dioxide insulator between the buried gate and the channel. This makes the charge leak out of the buried gate somewhat faster. The more xrays that pass through that area, the more ionization and the faster the charge leaks out. This ionization is irreversable, and causes permanent damage.
Whether the damage actually causes the bit in question to revert to a 1 depends on the strength of the xray source and how long (total across all the sessions) your computer has been bathed. An airline xray machine is unlikely to erase a bit if your machine passes through once. But if you travel a lot, then its almost certain that you'll suffer at least a one-bit error.
In short: don't let the airport security goons xray your laptops, palm pilots, digital cameras, or anything else that has CMOS EEPROM memory.
Every airport security checkpoint in the US has alternate procedures for electronics (generally involving a swab and a "portable" gas chromatograph to search for nitrogen compounds). The goons will argue with you, but it's worth the annoyance.
I've done this in Las Vegas, Los Angeles, San Fransisco, San Jose, Seattle, Denver, Sioux City, Minneapolis, and New Orleans. Those airports pretty much run the gamut of size from little podunk warts to huge transport hubs.
The FAA's assertion that airport x-ray machines dont damage electronics is a bald-faced lie.
-- Nolite audere delere orbiculum rigidum meum.