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Gamma rays and electrical systems

  1. Feb 22, 2006 #1
    Wasn't quite sure where to post this considering it talks about 2 subjects, but i guess this is a good place to start. My question is: How [if at all] can high energy EM waves affect electronic systems? More specifically gamma rays.

    I am by no means an electro-physicist, cosmic radiation is a new field for me. But as I understand it, gamma rays have a high energy and can penetrate most materials except for the earth's atmosphere. Upon colliding with electrons in other atoms, they lose energy and slow down, eventually stopping. But does this colliding with electrons interfere with the flow/energy of electrons in electrical equipment?? We all know electricity is just 'free flowing' electrons, not attached to atoms. But if gamma rays collided with them, could their flow be slowed or some energy drained??

    Maybe this is all nonsense, but that's fine.. I'd rather get my physics facts straight. Thanks ;) all input wlecome
  2. jcsd
  3. Feb 22, 2006 #2
    My understanding is that gamma rays can indeed affect some electronic components, such as high density DRAM chips. In a computer with L1 and L2 cache, for example, it is possible for gamma rays to corrupt data by "flipping" a 1 to a zero, or a zero to a one within the DRAM gates.
    I have a link to this somewhere, and I will find it if you wish.
    What I do not know is how critical this potential corruption is, nor how statistically frequently this happens, or with what other electronic components might also be affected.
  4. Feb 22, 2006 #3
    good, thanks for the response. yeah id love to see that link if you can find it. This topic occured to me while researching communication satellites and the cosmic dangers they encounter while orbiting earth. What if these gamma rays disrupt or damage the circuitry and sensors.. crippling our communications. Or alter the calibration of sensitive measureing equipment. it hasnt really happened thus far but it might be something to consider. Any more info on this would be appreciated.
  5. Feb 23, 2006 #4


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    When gamma rays pass through a substance, they leave behind ions when they "kick" electrons out of their bound states by interacting with the electrons.

    This is why gamma and x-rays get the name "ionizing radiation".

    The effect of ions on circuits depends on where the ions are generated. Many circuits use reverse-biased junctions for isolation. This is true of almost all commercial IC's, which are constructed by growing an epitaxial silicon layer on top of a silicon substrate. The isolation between the substrate and the epitaxial layer is in the form of a reverse-biased semiconductor junction. When a gamma ray generates an ion in such a reverse biased junction, it causes a current to flow where currents are not supposed to flow.

    For an overview epitaxial layers see for instance

    Effects of the ion-induced current flow can range from "bit errors" to destruction of the circuit, depending on the amount of current and the amount of power dissipated.

    Military circuits can be "hardened" to be more resistant (though not totally immune) to ionizing radiation. One way of doing this is to replace the usual silicon substrate with an insulator, such as silicon on saphire (SOS). However, this is more expensive, because it's hard to grow the single-crystal silicon structure required on top of saphire. Silicon grows best on top of silicon. (Continuity of the cyrstal structure is one of many important factors in making transistors work properly.)
  6. Feb 23, 2006 #5
    man that is a great response, thanks a lot. i appreciate such a good explanation and it answered my question perfectly. peace
  7. Feb 23, 2006 #6


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    I should also mention that current state-of-the-art process technologies use transistors which maintain their state with only a few thousand electrons. Sometime in the next decade, we'll be producing chips which use fewer than ten electrons per transistor.

    Considering that a single energetic gamma ray can ionize tens of thousands of atoms, it's obvious that radiation will become an increasingly daunting problem for microelectronics in the coming years.

    - Warren
  8. Feb 23, 2006 #7
    Indeed, this problem is not only likely to not go away, it will increase. As the density configurations of IC's evolve into a lower "trip-state" environment there is an increasing chance of abrogation due through hard radiation interference(external cosmic/gamma rays or internal radiation)

    Internal radiation?

    Take a Geiger counter and examine your computer. There are Plutonium and other radioactive elements existant in your computer; most notably from the planar motherboard and similar structures.
    This can have an impact on high density memory gates which are intolerant to the ionization effect.
    OK... it doesn't happen often, but there is something to be said about this with regards to buying "high quality" motherboards and such.
    What I am most concerned with is that as the density of the computational gates increase, the likelyhood of bit-error increases due to this interferance effect.
  9. Feb 24, 2006 #8
    hmm this is interesting news. so would it be more appropriate to say: radiation will negatively affect a system's memory/computations? Rather than its core elctronics?

    if thats the case, how weak/powerful would the radiation have to be to be a serious threat?
  10. Feb 24, 2006 #9
    I do not know the answer to your last question, though I can suspect that it has been examined enough(by NASA, the military, etc) that there exist some good literature on the subject somewhere.

    With regards to your first question, though, it's hard to say. Probably most "errors" caused by this are temporary and relatively benign with respect to the core electronics, but undoubtedly a high enough radiation exposure would permanently damage sensitive electronic components.
  11. Apr 3, 2011 #10
    Ah, a topic that needs resurrecting. I've been wondering if it is even possible to shield a robot/remote control device that can stand up to gamma rays.

    Is there any other option to build a remote controlled device? That would work while being irradiated by intense gamma rays? It seems an important topic at the moment.
  12. Apr 4, 2011 #11


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    It is unlikely that you could completely shield it from gamma rays. At least without having massive amounts of heavy shielding, which is the opposite of what you want in anything having to go into space. Current computers avoid the gamma ray problem with self correcting memory and computer chips and various other things. The gamma ray still affects it, but it can be corrected.
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