So I was at the dentist's yesterday, and we were talking about dental technology, and how for example RX (Röntgen, aka X-ray) sensitive CCD have replaced photo-chemical RX in dental imaging. I forgot to ask her what the lifetime of her sensor was, but I've always learned that RX is Very Bad™ for ICs. I don't think CCDs are an exception.

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Are there techniques which make an IC less vulnerable for RX rays, or will my dentist have to replace her sensor 3 times a year?

Talked to my dentist again this afternoon, and asked her about the sensor. She's been using it for 7 years now, so it doesn't seem to be so much of a problem.

  • \$\begingroup\$ Xrays will not just destroy a transistor. They will just inject carriers. It is cases involving things like Flash when knocking the electrons off can cause bad memory state or certain conditions where you can cause trigger both gates in a mosfet that will cause you damage. Our CCDs seem to be resilient to most gamma radiation also, it is only the neutron radiation that destroys things completely. \$\endgroup\$ – Kortuk Jul 15 '11 at 10:13
  • \$\begingroup\$ What is "RX"? Normally it means "receiver" in electronics. \$\endgroup\$ – endolith Jul 15 '11 at 15:22
  • \$\begingroup\$ @endolith - I said "Röntgen" in the question, X-ray if you want. RX is the common term in medical imaging. \$\endgroup\$ – stevenvh Jul 15 '11 at 16:12
  • \$\begingroup\$ @Kortuk - IIRC from my courses (admittedly many moons ago) X-rays will introduce lattice faults in the crystal, though which the dopants can migrate. Something like that. Makes sense? \$\endgroup\$ – stevenvh Jul 15 '11 at 16:34
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    \$\begingroup\$ @stevenvh, I am wondering if RX is European, the Medical Physicists have never used that term in conversation and when speaking with our Belgian main office I have never encountered the term. I know Röntgen, but only as it pertains to REM and RAD, both units replaced in EU by Gray and Sievert. \$\endgroup\$ – Kortuk Jul 16 '11 at 1:18

RX is perfectly applicable to CCD IC's. There are many products, like solder paste inspection cameras, which are just arrays of hundreds ccds. with some motion to sweep across gaps between sensors.

There is nothing destructive happening in electronics related to RX, if it is schematically designed to be immune to current increase across all junctions caused by RX. For lowish levels of Rx.

High level RX/Gamma rays will move curves to thermal runaway points so, that devices will instantly fry themself, but the destruction will be done by normal DC power, not RX itself.

Edit: After some reading an googling about XRay CCD. The sensors are actually normal cameras with normal optics watching a scintillation screen.

Next incoming invention can be a tiny oscilloscope tube with little camera watching it in a DIP-40 sized assembly.

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