HP41C x-ray

[Thomas Klemm]

Found an x-ray print of an HP41C here.

[Randy]

FWIW, it's a very late model C fullnut with card reader and modules installed. Pretty neat! Thank you.

[Dan Grelinger]

What module(s) are installed?

[bill platt]

Randy is a superman of calculators but he'd need X-ray interpretation clairvoyance in addition to X-ray vision to tell that ;-)

[Dan Grelinger]

Bill,

Maybe. But I think I see clues that would allow someone to identify at least one of the ROMs. ;-)

Dan

[Ed Look]

Um... the x-rays won't harm the chips?

[Michael de Estrada]

Do the X-ray machines at airports damage electronic equipment?

[Garth Wilson]

My cameras and calculators have gone through airport X-ray machines many times with no damage or memory loss.

[Mike Morrow]

I've been passing my HP42S, HP50g, and HP17BII almost daily through the x-ray screening at a U.S. nuclear power plant for many years. It's at least as penetrating as the airport version. Before that, my HP-41CX and HP-15C made daily trips through the machine.

I'd say empirical evidence says that there's little to fear.

[Michael de Estrada]

Actually, it's all about the dose rate and the vintage of the IC's. Dose rates less than about 5000 rad gamma will not hurt anything, and I think X-ray machines are way below that level. Also, older IC's are more robust than newer ones because they keep reducing the size of the circuitry. I had one project where I had to source some new old stock IC's manufactured before 1985 to ensure that they were made on a larger circuit gage to withstand radiation within reactor containment.

Edited: 31 Mar 2009, 11:52 a.m. after one or more responses were posted

[Ed Look]

I see. I was wondering because of talk in the past about radiation-hard components. This made me think that the old silicon could not handle higher energy radiation.

[Mike Morrow]

Quote:

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Actually, it's all about the dose rate and the vintage of the C's.

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The total integrated dose is typically more significant than the dose rate.

Quote:

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Dose rates less than about 5000 rad gamma will not hurt anything, and I think X-ray machines are way below that level.

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You've cited a dose, NOT a dose rate. Dose rate is expressed in RAD per unit of time.

The dose received in a typical x-ray screener is likely at least six orders of magnitude smaller than the value cited.

[Michael de Estrada]

Yes, you are absolutely correct. I should have said that the threshold TID for damage to ICs is above 5000 RAD gamma. During a lifetime of passes through an X-ray machine, the TID would be much lower.

[Joerg Woerner]

You might watch these images, too:

X-RAY

Enjoy!

Regards,
Joerg