Intel plans to tackle cosmic ray threat (actually they have been working on it for at least five years...austin)
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From: Symon on 8 Apr 2008 11:43 "austin" <austin(a)xilinx.com> wrote in message news:ftg25m$p2m2(a)cnn.xsj.xilinx.com... > > Intel has also been working very quietly on this, with much less press. > Hi Austin, I wondered what were your thoughts on their patent where "The cosmic ray detector [built into the device] is therefore designed to spot when rays have caused interference and then tell the chip to repeat the command." ? I guess in an FPGA it could trigger a readback to ensure the device was still correctly configured and/or issue a user logic reset. Cheers, Syms.
From: austin on 8 Apr 2008 11:56 Symon, Well, that employee should be fired: that is the stupidest thing I have ever read. It isn't even science -- detecting neutrons! Pure BS! A neutron is an uncharged particle, that goes through 10 meters of concrete before it gets stopped. Detecting one is just......stupid.....idiotic..... (breathe in, breathe out.) Their PR folks are probably going nuts on this one! Was that April 1 dateline? Anyway, Intel is pretty savvy, and they are not standing still. If you use their parts, you need to request their Soft Error Effects roadshow. It is only given under NDA, so although I know it exists, and I suspect I know what is in it, I have never seen it. I have seen IBM's "show" and they certainly have their act together. As do we. IBM's "show" is under NDA, however, so I can't say anything about its contents. Our roadshow is available by request from your local friendly FAE, and it is no NDA is required (why would we hide we are the best?). Remember: per the JEDEC89A standard, there are three ways to characterize soft error effects. Be sure to ask which ones were used, and their degree of confidence. If they won't share this with you (under NDA), then they are hiding something, something very very bad. Austin
From: austin on 8 Apr 2008 13:16 At sea level, 93% of particles from the cosmic ray shower are neutrons, and 7% are protons (see JEDEC89A). There are 12.9 per square cm, every hour, passing through everything (for New York City, up to 25X more on mountain tops, 300X at 40K feet, less at the equator, 10X at the poles...). There are also electrons, muons, pions, and a host of more exotic stuff, but hose either don' matter (do not affect anything), or they are absorbed quickly, or decay (even a lone neutron decays in 11 minutes!). So, like I said, that is the dumbest PR I have read. It gets the first prize for ignorance about soft error effects. Some Real Science: http://www.xilinx.com/support/documentation/white_papers/wp286.pdf Austin
From: Jon Elson on 8 Apr 2008 15:25 austin wrote: > Symon, > > Well, that employee should be fired: that is the stupidest thing I have > ever read. > > It isn't even science -- detecting neutrons! Pure BS! A neutron is an > uncharged particle, that goes through 10 meters of concrete before it > gets stopped. Detecting one is just......stupid.....idiotic..... > > (breathe in, breathe out.) > Right, having worked with a nutron detector array, detecting them is REALLY hard, and not something easily done on a chip. However, most neutrons pass through chips easily with no interaction, and so can be ignored. What you have to detect is if the neutron was CAPTURED, and deposited energy in (or very near) the active circuitry. That will release some energy (could be charged particles, could be Gamma rays) that could affect the active circuitry. The gammas could be detected from a distance, but they can be quite directional and local, so detecting them could be tough, too. > Their PR folks are probably going nuts on this one! > > Was that April 1 dateline? > Really! Just detecting a neutron or Alpha hit could be difficult, although detecting a cosmic ray shower is a lot easier, as the shower of charged particles greatly increases your probability of detection on a small detector device (probably just a diode). But, then, the REAL problem is how to CORRECT any malfunction that may have ocurred. Reducing the probability of corruption, as Austin descibes Xilinx has done, seems the most reliable and provable scheme. Proving you can correct corruption from a hit anywhere on a chip, while running ANY program, at any time, seems like fantasy. Jon
From: Jon Elson on 8 Apr 2008 15:35
Symon wrote: > > Ok, here's another question. As the uncharged neutrons don't interact with > much, indeed you say they can go through 10 metres of concrete, I can't see > why the highly interactive remaining protons aren't the real danger, even > though they only comprise 7% of the total, not the 93% neutrons? Maybe none > of the original protons reach the surface, but the 7% protons are produced > by secondary neutron collisions? The protons interact VERY strongly, due to the charge. As most electronics is housed in something, the housing usually stops the protons, although there will be Gamma radiation when they hit, and that can penetrate the housing. If you put a bare photodiode outside on a dark night and reverse-biased it, you could pick up these interactions easily with an oscilloscope. With a little digging into the physics, you could discriminate alpha hits from protons, etc. Of course, cosmic ray showers deliver so much "stuff" that you'd just see big pulses without being able to pick out the fundamental particles. Oh, one other aspect is "stopping distance". Very energetic charged particles zing through stuff with minimal energy deposited into the material, until enough energy has been shed, then they interact and stop suddenly. So, the very high energy primary particles are not much trouble, it is when they either lose energy by travelling through something or create secondary particles that the energy is low enough to create ions. So, the protons are not likely to ever make it into the silicon directly. Secondary Alphas and lots of Gammas will be bouncing around, and those could deliver energy to the chip. Jon |