Bizzare? anti correlation between gammas and neutrons

[Doug Coulter]

Right. When a positive charged particle (assumed here) strikes something, it can at most strip an innermost electron (or more) and create a characteristic line from that, and extremely rarely make a near-full energy photon by direct braking radiation if it happens to (almost) hit a target nucleus head on, which would be a much more rare case if all I know is true. But this isn't rare, it's practically swamping the detectors!

Due to conservation of energy and momentum, and the low input energy (which can almost be neglected here compared to that of a fusion) we assume that the fusion products take on energies in relation to their weight, with momentum being conserved by giving more energy/velocity to the lighter fragments. What little data I have (and I'll have to go fish through it all again, and could use help, most of it is here) seems to say that. So when you have a light and a heavy product, both get the same momentum to conserve that, but the light one gets most of the fusion energy as velocity to make all the conservation laws happy, is what things boil down to if I understand correctly.

We know from both theory and practice that with 50kv power supply and some non fusing gas in there, that at most we get 50kev photons out from electrons hitting the tank walls, and we actually get a continuum from there down to zero, with some peaks at the K,L,M lines of the substances involved -- just as the books say. I've found no exceptions in the literature so far to that, or in practice here. You get the K,L,M etc lines and some in-between, and at the Z's of the components in the tank metal and lead, the K line (hottest) isn't high enough to explain what we see. By quite a lot!

Therefore, it becomes hard to explain these very hot gammas. I have tried this with a piece of lead that should stop nearly all gammas under 100kv (according to the radiology safety charts published elsewhere here), and we still see stuff getting through the lead -- lots of it, which kind of eliminates some of the questions about the detectors. Now, whether that's neutrons, which we know get through the lead at some level creating scintillation light in NaI, we can't be very sure at this point, but in general NaI isn't very neutron sensitive (no light atoms in there other than maybe in the glue that holds it together) except for activation of the I, and so far I'm not seeing that -- that would produce a very long tail after shutting down -- long half life, and I don't see it yet.

Further, a direct hit of a 2 mev neutron on an atom in the scintillator should not produce 2 mev worth of excitation, due to the conservation of momentum when something light hits something heavy - the neutron should glance off with most of its energy retained when striking something much heavier. Yet we're seeing a lot of 1-2 mev.

I would tend to believe that we're not seeing the about 16 mev gamma which the very rare straight to He reaction produces (total energy is 22 mev for that but some stays in the product, again due to momentum conservation), I'd think that would really stand out, even assuming some output energy compression due to limits in the NaI. What we see instead is a lot of 1-2 mev or so energy -- and it's really a lot, far too much to explain by almost head on collisions with target nuclei, which should be relatively rare due to the very small sizes involved vs the spacings of nuclei in solids. That cross section should be really tiny.

As to the time variation...I don't think anyone has an explanation of any variation. All the literature I have seen simply says you get this much percent of this or that reaction pathway, but all this data is from thermal conditions. We don't have pure-thermal conditions, we're in a new world. I can hazard a guess or few, but that's all they'd be -- guesses.

Here's one I've discussed with CurtisF a long while back.

Lets suppose it matters what the instantaneous relative orientations of the D nuclei is a the time of tunneling into fusion matters. There is an orientation as there are two nucleons in a D ion.
Think of it as a little dumbbell. It can therefore come in proton first, neutron first, or anywhere in between -- sideways with the protons at the same ends, crossed, protons at opposite ends, anything you can do with two dumbbells. It can spin around the virtual center of mass between the two nucleons. It can have oscillations in length. I'd suppose the net spin (in terms of the physics definition of spin a single particle can have) of any D is zero (from NMR science), but that this could be created by the proton or the neutron being "spin up" and the other "spin down" as well. If I've read correctly, all these sorts of things are quantized (eigenvalue states) but even l==1 implies that this is happening very fast, well above GHz for the lowest level, much faster than anything we're doing here. It seems reasonable that the relative orientation of all these things would affect probabilities of fusion at all, and relative probabilities of which reaction path we get. I would imagine without actually running the numbers, that any of these rotations happen "zillions" of times during the flight of any ion in our setup, but that their state when in close proximity does matter, and that somehow we are creating conditions where a bunch of them are either this way, or that way relative to one another at the point of closest approach, which is at least possible even though the highest frequencies of any noise we see barely makes it to VHF, much less tera-hz and beyond. In fact, I'd guess the basic energy levels involved in the stretch mode of the dumb-bell is on the order of the stripping energy -- a couple mev, so we are most likely not exciting that directly, unless we have a situation where that's a high quantum number and we can have excitations that are sub-multiples of that (possible).

There are other things in nature where pumping at some sub-multiple (sub harmonic) of something will up-shift the energy -- think for example of frequency doubling in some non linear crystals used to make green laser pointers with an IR laser diode. There are many other examples at lower frequencies in electronics. There are also examples of multi-photon absorption leading to output energies that are higher than any single input energy event. They are not common, however, and usually take very high fluxes of whatever to get a multiple absorption before the effects of the first one decay back to the ground state, and as far as I know, we don't have a fluxes of that level -- in the laser biz it tends to take super high energy densities that are usually prefixed by "tera" or bigger implied exponents yet.

This is a possible mechanism, but frankly, it falls into the realm of gassing about cosmology over beer and pizza (a fun game since no one can go out there and make measurements that prove you wrong, but not terribly useful) -- I'm not claiming I understand what's going on in there well enough to make even an enlightened guess here - other than we DO see an effect (and will take much more data to see what else we can learn about it) so something has to be happening -- the trick is fitting into things we already know are true in nuclear physics, which is what the above is a perhaps weak attempt to do.

The above has far too many "ifs" in it to make me happy. What I want to find is "what" and "why" and "can I make it do this on purpose". Because it's truly new science if it's not just instrumental artifact and would have applications in a lot of fields besides this, and be perhaps one of the first tie-ins of detailed quantum effects in nuclear interactions where a classical model (orientation/frequency/phase) rather than a pure probability has been seen -- we ARE at the right size/energy scales for that sort of thing. It would imply the ability to do things with the strong force from a more macroscopic scale, by pre-polarizing things at a distance, so they are "in phase" in some sense when they get close enough for the strong force to act.

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There has to be some explanation after all. I'd prefer one that didn't involve, you know, magic, spirits, or something else completely off the wall, and this was the best we could do without invoking things like that, perhaps due to our limited ability to imagine. That's where everyone else here is supposed to come in -- we might have missed something that seems obvious to someone else, and this is where "many eyes" often make breakthroughs. I kind of doubt we need string theory or much of anything outside the standard model here -- just a more insightful interpretation of the existing math should do (a guess, but this is the kind of guess I'm good at).

So, here we are facing the unexpected, and tantalized by the fact that this implies there's something we don't know that might help a heck of a lot if we did understand it better.
We have that contaminated petri dish culture with the strange organism that is affecting the ones we wanted to grow, just as in the discovery of penicillin. Now, it's on us to figure out what we have, and try to make some good out of it, rather than throw the thing in the garbage and fire the sloppy lab assistant that didn't ensure the culture was pure.

Obviously, I need to take more data, and I encourage anyone else out there with a fusor to take a look at this too. Perhaps one of will notice something I haven't yet. There's really only two places this can go -- a big "DUH" moment, or we've just hit a jackpot, and one that goes beyond just the ability to control fusion reactions better. Obviously, time will tell, but I'm the impatient sort so I'd like it to tell soonest. If we can get nature to do this more or less by lucky accident, then the possibilities with some "malice aforethought" seem pretty wonderful.

[Doug Coulter]

Well, in some searching, Bill found a paper that is semi-relevant to this, but which still doesn't answer much. Since it's interesting, I'll attach it here.

XRaysProtons.pdf

Paper on fusion X ray sources

(94.56 KiB) Downloaded 274 times

This discusses among other things, p->d fusion, which I have to think is possible, since the main contaminant in our D gas is H. As the high energy X rays show up right at the start of a run, it is very unlikely that it was any of the other reactions of fusion byproducts, since at that point, there weren't any (not that there ever are many anyway -- but it could be something to look into as a run progresses). At any rate, the things mentioned in the paper are in the right energy range for what I'm seeing, though I think I'm seeing entirely too much for any reasonable estimate of what the fusion rates and tank content are.

Still doesn't explain the time varying nature of this. I will be taking more run data soon. I'm building up a new preamp for the 3he tube that is right next to where I put the NaI head, and a power supply for another NaI head we have, so we can get 4 channels of data and kind of eliminate some possible errors. This will result in having both types of detectors on both sides of the fusor, so if something is "beaming" or moving, it won't fool us like the current setup possibly could.

[chrismb]

I did discuss p+D on fusor.net along time ago**, with little effect.

It seems plausible to me that there is an x-ray continuum, with a few peaks, from the reactions you are mentioning. Also, my quick calcs suggest that fusion product p and T both have a good chance at their own fusion with a background D before their fast route takes them to the shell, and once there they then have a second chance at a fusion of their own with embedded nucleii. Plenty of reaction types there, and plenty of brems emissions routes.

I'm still strongly of the opinion that there is likely to be a lot of embedded D where the fusor-beams intersect the shell. Stands to reason? So there will be a heightened reaction rate at those spots with the fusion p and T that happen to go in that direction (and also some localised neutron production).

The thing that remains for explanation is the inverse correlation you are saying you see. Or is this just at the start of the run?

I have to say that I do think this is a much stronger line of inquiry to consider these other reaction types than suggesting variations in the 3 DD fusion branches.


**[and got the usual "don't bother discussing that!" type of response; http://www.fusor.net/board/view.php?bn= ... 1210503737 . Though, I got some suggestions (!) to buy a BTI and an ion-chamber pen, rather than the pocket scint. As it happens, the pocket scint is still perfect, and the BTI has leaked and now has permanent bubbles. Waste of $200, if you ask me....]

[Doug Coulter]

I mostly agree here. However, the prospect of varying branching ratios under deliberate control is pretty darned enticing too -- and it does seem possible. It just got a lot harder to prove with the gear I have in service now.

And, don't forget 3He in there too -- real good fusion prospects for that one as well. I saw that anti-correlation from the start through shutdown.

They are talking about bremsstrahlung which yes, is a continuum with some high energy "tails" if I read that correctly -- I didn't read for full detail and math once they got off the stuff I thought was relevant to this investigation. Strange that we only found one paper with even a shred of relevance....kind of gives me hope there's some real science left to do that's do-able by us types.

What I need and don't have yet is a real multichannel analyzer -- we've had bad luck buying them surplus and have about 3 that don't work and don't have enough manual information to fix, so far. So I think I'm going to wind up building one soon -- at least I'll know every flaw and how to fix it later. But I have so many half finished projects, I'm not going to start another just yet -- I need to clear the decks a little more first, since I have:
1. Turbo controller
2. Standard counter system
3. Hooking up the rest of the detectors I have already (pre-amps, power supplies)
4. Leak fixing -- just got in with a new tank of He for that, but at 2 e-5 the mass spec isn't much help at all, mean free path is much too short to get good lines for the 3" path in the thing.
5. FT repair/add a special part to conduct the charge off the ceramic part to the center electrode, instead of having it arc through the supporting quartz.

A PIC should be able to do a decent MCA with a peripheral sample/hold and some logic to handle the quick pulses (the sample/hold inside one is real slow, 10uS) -- I've been modeling on paper for awhile on that. I don't think the soundcard one is going to be at all fast enough to handle the sheer rate of hits on my NaI head, and moving that across the shop to reduce the count rate merely means I get more scattering-type junk between any lines. As the old joke goes "for best accuracy, remove all air from the entire lab first". Kinda hard to do that here.

I don't have a clue how much D is stuck in the walls. They get pretty hot quickly during a run. Surely there's some in there though, and I suppose I could contrive a test to see about that, like pound some in quick, pump down, backfill with argon, run again, look at the mass spec after during the next pumpdown (it won't run at fusor pressures, or even close, due to the short mean free path then). Even at e-5 mbar the peaks are really hugely wide humps about 6-7 mass lines wide. At any rate, you'd have to think that after decelerating in the field, the ions wouldn't be going super fast and embed deeply -- but really, how much of which charge is going which way how fast where is still an open question to me, one thing I'm looking at. Really, we can't suppose that the applied field is THE field everything sees, due to all the electrons in there too. In fact, one of the takeaways from that thread where the scope shows crazy big positive pulses during a negative going drive from an NST. That would almost have to be induced charge from a "bunch" of ions going past that grid -- back and forth at a couple of Khz, which is itself a pretty weird number when you think about it -- way too slow -- and it would have to be quite a bunch to make that signal, would it not? This only happens after we've just swept out the electrons on the other half cycle of the NST frequency.

I did learn while investigating targets for beam on target (another project getting started here) that the ideal target is a little different than a SS tank wall. All indications seem to be that you want a light element (like Ti) in a very thin film, backed by something high Z and impervious to hydrogen (silver, gold, copper). The idea there is that the low Z matrix on top holds some D, but doesn't itself slow the incoming ions down as fast as something higher Z would, which makes me want to think of things like Be or B for that, actually -- or even carbon. You can for example drive ions into gold, and they stick pretty good, but by the time the next one comes along, it's been nearly stopped by interacting with the gold atoms -- no fusion.

But I don't think Be or B will load up well with D. In the latter case, I'd bet on chemical reactions (borane)? I do see some light hydrocarbons after a run with graphite in there, for example, not much, but enough to be fairly sure they're real.

Just to drop in a nugget of info for that, the best design seems to be about a 1u layer of Ti, over something thick and thermally conductive that has low permeability, like silver. This, I can make for sure, at any rate, and do it by simply making the target part of the electrode itself (copper), plating it, then evaporating some Ti on top. That should handle the heating issues pretty well, as you need to keep the target under 200c to keep any D in there (and BTW, the tank walls in the fusor reach that temperature all the time, and get there quick with power on, even with a fan blowing on them).

At any rate, unexpected things like this (and that pulsing) are what makes this worthwhile to me -- the possibility that I might actually discover something new, since none of this seems to be in the literature already. So, the experimental plan kind of makes itself at this point -- figuring out what to do next is usually the hard part, but not just now. I now have a ton of 'known unknowns" to look for.