Can Customs X-ray or electromagnetic arcs damage circuits? - Page 1
Forum section: electronics / general

author: luiHS
author_rank: Frequent Contributor
timestamp: July 09, 2021, 03:46:53 pm
content: I am making shipments to my clients, of various circuits that I manufacture, and I find cases in which the product is installed and it does not work for them. I test everything before shipping.Specifically, a board with a Kinetis MK66 microcontroller, the customer returns it to me, I test it and it doesn't even allow programming, it's locked.Two other cases, with Raspberry units that the video output does not work. It is not that it has failed them after a while of use, it is that as soon as it arrives, they install it and it does not work, when I here check everything before sending it.And since there are already several cases, and not all of the same board, one with my board that has a Kinetis MK66, and another two with Raspberry video failures, I don't know what to think about. The only thing I can think of is that the X-ray or electromagnetic arcs from Customs can damage the circuits, and if I could avoid it by putting the boards inside antistatic bags.

author: TimFox
author_rank: Super Contributor
timestamp: July 09, 2021, 04:18:38 pm
content: If Customs officials handle your un-shielded circuit boards, they could damage the components with ESD, due to static charges on their hands.If your components are ESD-sensitive, as most semiconductor devices are, the boards should be shipped in anti-static containers or bags.X-ray damage to semiconductors is possible, but not likely. Photographic film will be exposed by the relatively-high x-ray dose applied to checked baggage in commercial airliners, but there is little damage with the lower dose applied to carry-on baggage.(Many of my suppliers use anti-static plastic for all shipments, to avoid stocking multiple shipping materials. When I received some 1/4-20 UNC stainless-steel bolts wrapped in pink plastic, I shuddered to think of the ESD required to damage such objects.)

author: esepecesito
author_rank: Regular Contributor
timestamp: July 09, 2021, 04:41:03 pm
content: I have 1000 times shipped (or received by post), carried on, carry on baggage, and dispatched photo film, and electronics, and have never had an issue. Inspection of electronics with relatively strong X-ray is part of the manufacturing process where I work, so I do not think it would be an issue.But cannot warranty it is not the problem.I'd bet ESD miss-handling. But customs deal with ESD all time... I would expect the know what they do... well... anything is possible...

author: TimFox
author_rank: Super Contributor
timestamp: July 09, 2021, 05:30:21 pm
content: Damage by x-ray exposure to normal photographic filmin checked baggageis well documented, but I have never encountered a problem with normal film (ISO 100 to 400) in carry-on baggage, although I try to avoid multiple passes through the machines when changing planes. In the US, I have the legal right to hand inspection, but that is not true in Europe and other jurisdictions.

author: Gyro
author_rank: Super Contributor
timestamp: July 09, 2021, 06:25:16 pm
content: Quote from: luiHS on July 09, 2021, 03:46:53 pmI'm not clear whether your products are built into enclosures or are just exposed PCBs.If they are PCBs, then you shouldabsolutelybe using antistatic bags. I would leave negative feedback for even an ebay seller if they sent me a board of any value without ESD protection.It's not just handling, by customs or even by the customer when opening your packaging, but bubble wrap and other non-conductive packaging can easily generate damaging voltages when being jostled around in transit.I don't think X-ray has anything to do with your problem. Far too many complex electronic products are shipped through normal commercial channels for this to be an issue.P.S. It is so easy to seal antistatic bags with simple heat sealers these days, so that the contents cannot be handled without cutting them open. ESD labels are cheap too to warn of the risk.

author: esepecesito
author_rank: Regular Contributor
timestamp: July 09, 2021, 07:15:55 pm
content: Quote from: TimFox on July 09, 2021, 05:30:21 pmI guess I was pretty luck... until 2007 I used to put in checked baggage 10 to 20 rolls of film ISO 100. Never had a problem. Not saying there is no problem... just I was lucky!!!

author: Zero999
author_rank: Super Contributor
timestamp: July 09, 2021, 07:54:30 pm
content: Antistatic packaging is cheap, so there's no excuse not to use it. I have returned some RAM I purchased off ebay, because it came wrapped in non-antistatic polythene bubble wrap. I admit, I was sort of lucky, because I had mistakenly ordered the wrong type of RAM and the seller wouldn't normally accept returns, but I had the right to return it, because it was packaged inappropriately.

author: TimFox
author_rank: Super Contributor
timestamp: July 09, 2021, 08:45:56 pm
content: Quote from: esepecesito on July 09, 2021, 07:15:55 pmVery high-power x-ray CT scanners were not introduced to checked baggage until around 2000, although they would not have prevented 9/11. It was in response to the bombing of PanAm 103 over Scotland in 1988 and the later crash of TWA 800 off the coast of New York in 1996, that was later determined not to be a bombing (although conspiracy theorists are still active).

author: LaserSteve
author_rank: Super Contributor
timestamp: July 09, 2021, 08:59:26 pm
content: I used to have problems with programmed PICs sent through the US Mail locking up.Its not the screener that will get you, but the sterilizer might...https://www.everycrsreport.com/files/20020327_RS21184_00fb5ade1ddf87462b0e1c3636ff96d1113878ad.pdfhttp://www.sfowler.com/investigations/Mail%20Irradiation.htmhttps://en.wikipedia.org/wiki/United_States_Postal_Service_Irradiated_mailNothing like a Rhodatron to get things stirred up.Would be nice to know what they are using, because at one point I know they were ordering big Linacs..I used to take b&W diagnostic film on airplanes with me as checked baggage, the first few layers of film in a pack would have an latent image of any metal salts in the logo paint of the package without evening developing. I had heard rumors of 230 KV CT machines in airport basements. The film was always packed in my tool kit so the MaS was being turned up to see what was in the clutter.Steve

author: TimFox
author_rank: Super Contributor
timestamp: July 09, 2021, 09:38:30 pm
content: I once looked at sterilizing anthrax spores during the anthrax terrorism scares. A common process to sterilize surgical instruments, where the contamination layer is very thin and long-range radiation is not required, uses the electron beamdirectlyfrom the linear accelerator to deliver a truly extraordinary dose (typically 25 kGy) to the bad stuff, without the conversion loss of electron beam power to photon power at the accelerator anode by Bremsstrahlung, although the x-ray beam has much longer range. (I don't remember how much was needed to kill anthrax spores, which are almost little rocks.) The lethal dose to a human is a measly 10 Gy (not kiloGray) or so, depending on dose rate. These electrons would also greatly over-expose a normal photographic emulsion, which is quite thin.