Recent content by Leb

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    Direction of Photo Electron Emission

    Well, that "any direction" answers seems to conflict with experiments from 1920-30's, I wonder why did they find a preferential angle...
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    Relative biological effectiveness (RBE) of photon and electron

    Thanks for the reply. I slightly forgot, what we were tought again and again, that photon interaction with matter can only occur via 3 processes (in which electrons occur anyway...). So in some sense, it's not the photon, it's the electron that's the culprit (alhthough it is the photon who...
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    Direction of Photo Electron Emission

    I was looking for information on how the photo electrons are emitted when under X-ray radiation. In this ancient review paper here http://journals.aps.org/pr/pdf/10.1103/PhysRev.30.488 [Broken] they state that the most common angles for non polarized X-ray beams (of various energies) range...
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    Relative biological effectiveness (RBE) of photon and electron

    mathman, could you give examples where a same energy photon and electron would give different results in terms of biological damage ?
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    Relative biological effectiveness (RBE) of photon and electron

    The title was too long, original question was: Why is the relative biological effectiveness (RBE) of photon and electron the same ? I was suspecting the charge of electron to possibly have some effect... Also, in biological matter, would there be a difference between photon damage and...
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    Why only delayed neutrons matter ?

    Ah, it's more clear now ! I don't really like the oversimplifications made. It makes sense why one has reflectors then. So basically, it is crucial how you make the pellets, how many of them are in a rod and how many rods per assembly. I think when I get too looking properly at cross sections...
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    Why only delayed neutrons matter ?

    Thanks for the analogy, I think I get it why the delayed ones do the work (because every text booork website tells you the same, but I am yet to find an answer about what happens to prompt neutrons). So IGNORE delayed neutrons (I think the question title is a bit misleading now...) My...
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    Why only delayed neutrons matter ?

    Thanks for the answer, but it is still not clear to me, how these prompt neutrons are controlled in the reactor ? I mean, maybe I am missing something - the prompt neutrons come from fission of your fuel and delayed come from fission from your FP. But how do you control the prompt neutrinos, to...
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    Why only delayed neutrons matter ?

    Hi all, I've been seeing this again and again, that delayed neutrons are the ones that are allowing thermal nuclear reactors to work etc. etc. What I do not understand is how are prompt neutrons controlled and how delayed ones are allowed to "do their thing" no problem ? Wiki says...
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    Method of characteristics and shock waves

    I did not notice I deleted that part. I got x = 1 - Ct (I did it by differentiating, and equating the logs. Are we still talking about the same problem as in the picture ? Because it says the shock forms at t=1, x=1. Anyway, never mind. I understand nothing. Thanks for your help anyway!
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    Method of characteristics and shock waves

    So x vanishes for t = 1/C... So the x intercept. If C is the "sigma" this confuses me even further...
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    Method of characteristics and shock waves

    It should be x = K (1+t) So a straight line, for some constant K. If I use the range x is in I get that -1<t<\frac{1}{K}+1. I think I am wasting your time by now. I think it could be high school maths that's my problem. I have no idea where I get K from and no idea how this leads to shock time...
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    Method of characteristics and shock waves

    Maybe you could tell me about how you think (your thought process) when you are drawing the characteristics (especially the sloping ones) ? I have circled the ones that maybe will make life easier for both of us. Because, however I approach it, I get nonsensical line. Let's say for the first...
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    Method of characteristics and shock waves

    I am still not sure if this all helped (not that your explaining is bad, but me being daft). I am now looking at shocks and weak solutions. I (think I) know how to mechanically get weak solutions, but when it comes to drawing the characteristics for the weak solution - I'm in trouble. For...
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    Method of characteristics and shock waves

    So where was I wrong ? (I have not really seen x being set to something before (except when playing around with limits)) Did you mean it like sigma (I take it these can be interchanged for t=0) ?
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