X-ray tolerant chips?

Paul

While I'm releatively sure these Stamp Chips et. al. get X-rayed all the time in our security conscious nation.·Has there been any problem that X-rays have caused?
--Paul

Mike Green

In terms of security x-rays, the only issue is the EEPROM. Most of these use a small amount of electrical charge forced into a layer of insulation to represent a zero bit and the lack of charge represents a one bit. This charge slowly leaks away (over many years) and this process can be sped up by X-ray exposure or a cosmic ray hit. It used to be that there'd be a quartz window over the chip in some packages so you could use a ultraviolet lamp to erase the chip (before you could electrically erase them).

In any event, the problem is that lots and lots of x-rays can, over years, speed up the loss of charge and you may lose bits in the EEPROM eventually. This is much like the issue with photographic film. Unprocessed photographic film will start to fog after a lot of security x-rays. High sensitivity film will fog faster much like high density flash EEPROM, with its smaller cells and less charge, will also react faster. Poorly maintained security x-ray machines may have higher x-ray exposures than well maintained ones.

I wouldn't worry too much about it. Your computer has these chips in it. Your cell phone has these chips in it. Unless you travel for a living ... and travel a lot ... it's not much of an issue.

Dgswaner

I worked as an X-ray tech at Foundry (testing), we would Xray all sorts of electronics for fun, I x-rayed my mp3 player. it was none the worse for the wear. We even "nuked" some components to see if they could take it. We never had a item become unusable as a result. but who knows what it did long term to them.

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A complex design is the sign of an inferior designer. - Jamie Hyneman, Myth Buster

Paul

Mike & Dgswanger,

Thank you both for the information. I was fairly certain that they were X-ray tolerant. The EEPROM would make sense to·be more sensitive. I remember erasing·eproms with a UV light back in the "COCO" days.

Paul