Found an x-ray print of an HP41C here.
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HP41C x-ray
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Post: #16
03-29-2009, 08:01 PM
 FWIW, it's a very late model C fullnut with card reader and modules installed. Pretty neat! Thank you. ▼
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Post: #18
03-30-2009, 04:14 PM
Randy is a superman of calculators but he'd need X-ray interpretation clairvoyance in addition to X-ray vision to tell that ;-) ▼
Post: #19
03-31-2009, 11:37 AM
Bill, Maybe. But I think I see clues that would allow someone to identify at least one of the ROMs. ;-) Dan ▼
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Post: #22
03-31-2009, 12:47 AM
My cameras and calculators have gone through airport X-ray machines many times with no damage or memory loss.
Post: #23
03-31-2009, 12:48 AM
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. ▼
Post: #24
03-31-2009, 01:16 AM
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 ▼
Post: #25
03-31-2009, 11:36 AM
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.
Post: #26
03-31-2009, 07:11 PM
Quote: The total integrated dose is typically more significant than the dose rate.
Quote: 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. ▼
Post: #27
03-31-2009, 07:39 PM
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. |