Sorry, it's just occurred to me what you're getting at. You're saying that as radioactive products are formed by, say, an alpha emitting process of uranium why do NONE of those products themselves then have odd, dominantly neutron emitting behaviour.
I would speculate that the answer is as follows - whether a nucleus emits a neutron or an alpha particle, both are mediated by the strong force and that if the particles bound within the nucleus achieve a quantum jump over that binding force, or otherwise is in a sufficiently excited state, then it would be thermodynamically more favourable to that nucleus to drop off an alpha than anything else. It's a bit like asking why petrol/gasoline burns into H2O/CO2 - why would it ever do a half-job and burn half the molecule off into ethanol?
For nuclear reactions, an alpha (4He) is the H2O/CO2 equivalent of the lowest energy product.
You might get a smattering of 'CO' and the equivalent is a smattering of neutrons (stretching the analogy!), but you have to deliberately do something to interfere with the natural 'burn' to get that. In the nuclear case, you have to jam in an extra neutron, for example, like in a uranium chain reaction.
As for the product that comes out of any decay, the same principle applies - if there is enough exitation energy to prompt another strong-nuclear decay then it would, again, prefer to drop off an alpha given half the chance.
If there is not enough energy to drive a strong decay, then the exitation energy will likely be released as a photon. The weak beta decay is a different beast altogether - a bit like the gasoline evaporating instead of getting to the stage of burning (gee - really pushing that analogy!!)
The reason why there are no 'imbalanced' nucleii already knocking around so as to emit a neutron in the first place is simply because, if you think of where it must've come from, the same applies. Whatever mechanism created that natural nucleus it would've shed that neutron already at that moment of the mechanism taking place, if it were going to imbalance the nucleus and leave it in a higher energy state.
Is this closer to a suitable answer?
best regards,
Chris MB.
FAQ - Why no neutrons exit atoms in natural decay processes
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Chris Bradley
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JohnCuthbert
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Re: FAQ - Why no neutrons exit atoms in natural decay processes
Apart from fission (which as has been pointed out is so rare as to be nearly non existent), does any decay process produce any particle that is unstable?
If not then this validates Chris's point about neutron emission being the equivalent of only partially burning things.
The whole point of decay is to get to the lowest energy state and an unstable particle isn't the lowest state.
If not then this validates Chris's point about neutron emission being the equivalent of only partially burning things.
The whole point of decay is to get to the lowest energy state and an unstable particle isn't the lowest state.
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Richard Hull
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Re: FAQ - Why no neutrons exit atoms in natural decay processes
I would question the statement that a neutron can't be emitted from an unstable nuclear state since any excited item to fall to a lesser or lower excitation would not emit another unstable particle.
Neutron emission is only seen to occur when just such an effort is desired by some unstable nuclear states. (drop to a lower energy state.)
The real reason is that no natural, continuing decay process here on earth is so over excited as to be able to emit a neutron. Neutrons are pretty locked into all matter on earth even naturally decaying radionuclides.
Richard Hull
Neutron emission is only seen to occur when just such an effort is desired by some unstable nuclear states. (drop to a lower energy state.)
The real reason is that no natural, continuing decay process here on earth is so over excited as to be able to emit a neutron. Neutrons are pretty locked into all matter on earth even naturally decaying radionuclides.
Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Chris Bradley
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Re: FAQ - Why no neutrons exit atoms in natural decay processes
There is a question still on the table here - we humans, along with supernovae and other 'unnatural' events, can create isotopes that release neutrons.
But of all those neutron emitting nucleii, are there any daughter products from those, after those neutron emissions, that also go on to emit neutrons?
My thinking is that there aren't any. Once they've bumped down the potential energy curve just once then they've done all their neutron emitting. The neutron emission is like 'settling up' the odd nucleons in the nucleus, and that only needs to be done once.
The point being that all materials we now find lying around on and in the earth have already done that 'settling up' and no longer have any inclination to emit neutrons - they may go on to do a thermodynamically favourable full alpha emission, but they have no further need to emit a neutron when they can do that alpha emission instead.
But of all those neutron emitting nucleii, are there any daughter products from those, after those neutron emissions, that also go on to emit neutrons?
My thinking is that there aren't any. Once they've bumped down the potential energy curve just once then they've done all their neutron emitting. The neutron emission is like 'settling up' the odd nucleons in the nucleus, and that only needs to be done once.
The point being that all materials we now find lying around on and in the earth have already done that 'settling up' and no longer have any inclination to emit neutrons - they may go on to do a thermodynamically favourable full alpha emission, but they have no further need to emit a neutron when they can do that alpha emission instead.
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Richard Hull
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Re: FAQ - Why no neutrons exit atoms in natural decay processes
Spontaneous fission is an example of a natural neutron emission process where daughter products also later emit neutrons. (prompt versus delayed neutrons)
Alpha emission is never seen to have energies where neutrons could be emitted.
The strongest alpha's are the 1 usec alpha emiters such as the radium daughter Po214 (Ra C') where the alpha energy max's out at around 7 mev, a near neutron emitting level!
Alpha emission, itself, is a mystery that may have clues. Why would an atom blow out such a monsterous particle (2 protons and 2 neutrons) as a unit item when the excitation energy is so far below that of a lone neutron emission level? Alphas range between about 2.5 to 6 mev in most natural emitters. The evidence has inspired a few to think in the direction of a nuclear shell model as a composition of Alpha particles.
So far as settling up all the odd neutrons in the nucleus............ Beta emission is also settling up all the odd neutrons in the nucleus as well. They are going bye-bye, but not being emitted.
It just goes back to how excited is the nucleus? All Beta emitters, (lots of them nautral), are also very neutron overburdened, they just don't spit them out.
Neutrons are atom builders and the nucleus hoards them unless excited to over 7mev.
There are no 7 mev+ unstable atoms on earth save for the occasional fission. Internally, neutrons can be assembled due to intense nuclear densities , electron capture, or dismantled via internal decay, Beta emission.
By theory the only places neutrons can be assembled are in stars or in the nuclei of atoms. A most interesting dichotomy of scale.
Richard Hull
Alpha emission is never seen to have energies where neutrons could be emitted.
The strongest alpha's are the 1 usec alpha emiters such as the radium daughter Po214 (Ra C') where the alpha energy max's out at around 7 mev, a near neutron emitting level!
Alpha emission, itself, is a mystery that may have clues. Why would an atom blow out such a monsterous particle (2 protons and 2 neutrons) as a unit item when the excitation energy is so far below that of a lone neutron emission level? Alphas range between about 2.5 to 6 mev in most natural emitters. The evidence has inspired a few to think in the direction of a nuclear shell model as a composition of Alpha particles.
So far as settling up all the odd neutrons in the nucleus............ Beta emission is also settling up all the odd neutrons in the nucleus as well. They are going bye-bye, but not being emitted.
It just goes back to how excited is the nucleus? All Beta emitters, (lots of them nautral), are also very neutron overburdened, they just don't spit them out.
Neutrons are atom builders and the nucleus hoards them unless excited to over 7mev.
There are no 7 mev+ unstable atoms on earth save for the occasional fission. Internally, neutrons can be assembled due to intense nuclear densities , electron capture, or dismantled via internal decay, Beta emission.
By theory the only places neutrons can be assembled are in stars or in the nuclei of atoms. A most interesting dichotomy of scale.
Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Frank Sanns
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Re: FAQ - Why no neutrons exit atoms in natural decay processes
I believe in the beginning there were only neutrons.
Protons and electrons are the decay products of neturons and this would explain entirely why the universe is neutral. Neutrality is not by chance but it is as it was in the begining (or shortly thereafter).
It takes protons to tend the neutrons and prevent their decay. The incestuous exchange that goes on between the substance of neutrons and protons (notice I did not say quarks) is in equilibrium. No more neutrons can, without external stimulation, be released from the exchange family group because there are just the right amount of proton tenders around. Neutrons can now have a bad day and not fission (etimology biological as well as nuclear) .
Frank Sanns
Protons and electrons are the decay products of neturons and this would explain entirely why the universe is neutral. Neutrality is not by chance but it is as it was in the begining (or shortly thereafter).
It takes protons to tend the neutrons and prevent their decay. The incestuous exchange that goes on between the substance of neutrons and protons (notice I did not say quarks) is in equilibrium. No more neutrons can, without external stimulation, be released from the exchange family group because there are just the right amount of proton tenders around. Neutrons can now have a bad day and not fission (etimology biological as well as nuclear) .
Frank Sanns
Achiever's madness; when enough is still not enough. ---FS
We have to stop looking at the world through our physical eyes. The universe is NOT what we see. It is the quantum world that is real. The rest is just an electron illusion. ---FS
We have to stop looking at the world through our physical eyes. The universe is NOT what we see. It is the quantum world that is real. The rest is just an electron illusion. ---FS
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Richard Hull
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Re: FAQ - Why no neutrons exit atoms in natural decay processes
Interesting thoughts.
I believe in the particulate evolution based on universal temperatures. Currently, charged matter dominates to a net neutral. I know there was an age of mesons, and other stuff prior to that each age lasting longer in time.
Save for isolated pockets of high temperature densities and random high energy collisional events, the remnants of age of the mesons is rarely seen today. The universe of the super subatomics is totally gone and they are all part of what we now know at the 3 kelvin point we abide in today.
Even in special events in regions of tremenedous energy densities found at the cores of man's mightiest machines, such existences, even stretched out in time by relativity, are in the sub microsecond class and much less for the pre-mesonic materials. They are not part of today's matter nor are they constituents, but entities that just can no long exist in space or in matter. They are what became, as we know it.
I imagine that the familiar forces we know, quite possibly, evolved or devolved, (your choice), right along with that which occupied each such age.
I believe in the particulate evolution based on universal temperatures. Currently, charged matter dominates to a net neutral. I know there was an age of mesons, and other stuff prior to that each age lasting longer in time.
Save for isolated pockets of high temperature densities and random high energy collisional events, the remnants of age of the mesons is rarely seen today. The universe of the super subatomics is totally gone and they are all part of what we now know at the 3 kelvin point we abide in today.
Even in special events in regions of tremenedous energy densities found at the cores of man's mightiest machines, such existences, even stretched out in time by relativity, are in the sub microsecond class and much less for the pre-mesonic materials. They are not part of today's matter nor are they constituents, but entities that just can no long exist in space or in matter. They are what became, as we know it.
I imagine that the familiar forces we know, quite possibly, evolved or devolved, (your choice), right along with that which occupied each such age.
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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DavidStewartZink
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Re: FAQ - Why no neutrons exit atoms in natural decay processes
Just wanted to mention that most earthly free neutrons are produced by lightning strikes (1000s / m^3), however that is probably not emission but electron capture by hydrogen.
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Carl Willis
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Re: FAQ - Why no neutrons exit atoms in natural decay processes
David, what is your source of information?
Numerous reliable references you can easily find with a Google search (as well as texts like Glenn Knoll's "Radiation Detection and Measurement") inform that the main source of neutrons at the Earth's surface is secondary cosmic radiation. This has been well-established for decades and in fact some cosmic activity monitors use neutron detection as a surrogate.
The origin of the cosmic secondary neutrons is not explained by electron capture on hydrogen (I strongly suspect your source of that tidbit is not a mainstream scientific one), but by spallation and a slew of other high-energy reactions, the other byproducts of which are also detectable (a variety of light radionuclides, muons, pions, etc.)
Regardless of whether some neutrons accompany lightning, the main sources of terrestrial neutrons and the means of production of those neutrons are pretty well established at this point and a quick trip to Google or your library will be usefully informative.
-Carl
Numerous reliable references you can easily find with a Google search (as well as texts like Glenn Knoll's "Radiation Detection and Measurement") inform that the main source of neutrons at the Earth's surface is secondary cosmic radiation. This has been well-established for decades and in fact some cosmic activity monitors use neutron detection as a surrogate.
The origin of the cosmic secondary neutrons is not explained by electron capture on hydrogen (I strongly suspect your source of that tidbit is not a mainstream scientific one), but by spallation and a slew of other high-energy reactions, the other byproducts of which are also detectable (a variety of light radionuclides, muons, pions, etc.)
Regardless of whether some neutrons accompany lightning, the main sources of terrestrial neutrons and the means of production of those neutrons are pretty well established at this point and a quick trip to Google or your library will be usefully informative.
-Carl
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Richard Hull
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Re: FAQ - Why no neutrons exit atoms in natural decay processes
As Carl notes, most terrestrial, (within the atmosphere), neutrons are of cosmic origin and are the result of Bev and Tev nuclear events as cosmic rays that have wandered the universe for God knows how many millions of years, slam into dense matter, like air, after exisitng in a hyper vacuum at near lightspeed velocities for a long, long time.
Neutrons are cherished and useful chunks of matter. But once outside the nucleus they were in, they are doomed to return to the hydrogen gas from which they were originally formed via beta decay, unless they join with another nucleus of matter before their death moment arrives.
Richard Hull
Neutrons are cherished and useful chunks of matter. But once outside the nucleus they were in, they are doomed to return to the hydrogen gas from which they were originally formed via beta decay, unless they join with another nucleus of matter before their death moment arrives.
Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Dennis P Brown
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Re: FAQ - Why no neutrons exit atoms in natural decay processes
Correct me if I am wrong but does not natural uranium (mix of the isotopes) undergo (rarely) spontaneous fission and release neutrons? As such, uranium ore should provide a low level emmision of neutrons. Of course, background cosmic ray effects would be an issue.
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Carl Willis
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Re: FAQ - Why no neutrons exit atoms in natural decay processes
U-238 is a source of spontaneous fission neutrons, about 0.011 n/s per gram. This is readily detected with sensitive equipment and appropriately long count times. I have an experiment in the Detection forum back in 2005 demonstrating SF as a probable source of neutrons from uranium. It is likely the most important source of neutrons in natural uranium under most conditions, but other effects can contribute significantly, such as
-(a,n) reactions on light matrix nuclei, typically those of oxygen in oxide minerals or compounds, which can be expected to be much more important if the high-energy / short-lived alpha daughters in the decay chain are present near equilibrium concentrations
-spallation induced by muons and other secondary cosmic particles of high energy (this effect is detectable if dense material like lead is placed around a sensitive neutron counter, and uranium could be expected to have a similar contribution)
-Carl
-(a,n) reactions on light matrix nuclei, typically those of oxygen in oxide minerals or compounds, which can be expected to be much more important if the high-energy / short-lived alpha daughters in the decay chain are present near equilibrium concentrations
-spallation induced by muons and other secondary cosmic particles of high energy (this effect is detectable if dense material like lead is placed around a sensitive neutron counter, and uranium could be expected to have a similar contribution)
-Carl
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Richard Hull
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Re: FAQ - Why no neutrons exit atoms in natural decay processes
Spontaneous fission was noted in several replies above.
Carl has put a fine point on it. A kilogram (~2.3 pounds) of pure, freshly refined U will have about 11 neutrons produced in each second. Most all will be lost (absorbed) and are undetectable within the mass, itself. Some microscopic few will slow (thermalize) and might induce reactions in the U235 contained (very rare). Fast neutrons from fissioning can also induce fission in the U238, also rare. However, a natural uranium reactor relies on these rarer processes to work! You just need many tons of refined U to trap and use those internally accumulating neutrons. (note: it can't be depleted U though).
Both fissile and fertile elements have natural decay rates as alpha only emiters. fission is not a major decay process compared to their normal particle emitting decay rates. (noted in above postings by me.)
Richard Hull
Carl has put a fine point on it. A kilogram (~2.3 pounds) of pure, freshly refined U will have about 11 neutrons produced in each second. Most all will be lost (absorbed) and are undetectable within the mass, itself. Some microscopic few will slow (thermalize) and might induce reactions in the U235 contained (very rare). Fast neutrons from fissioning can also induce fission in the U238, also rare. However, a natural uranium reactor relies on these rarer processes to work! You just need many tons of refined U to trap and use those internally accumulating neutrons. (note: it can't be depleted U though).
Both fissile and fertile elements have natural decay rates as alpha only emiters. fission is not a major decay process compared to their normal particle emitting decay rates. (noted in above postings by me.)
Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Chris Bradley
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Re: FAQ - Why no neutrons exit atoms in natural decay processes
For cross reference purposes: http://en.wikipedia.org/wiki/Natural_nu ... on_reactor
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DavidStewartZink
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Re: FAQ - Why no neutrons exit atoms in natural decay processes
Of course cosmic rays don't produce neutrons through electron capture, that's a silly idea, and also: yours.
And say what you will about "science establishing this or that", but strangely enough science merely asserts, and very often when dealing with natural rather than theoretical phenomena most of the assertions are just so much hot air. To be replaced next week by different hot air. Nature is complicated.
Most cosmic ray neutrons don't reach the surface of the earth. Lightning neutrons—which have been reported for decades but no one bothered to test for them until recently—form very near the surface and are very dense.
I'm a bit surprised people so willing to assert authority do so little to keep up. I'm also saddened that no one googled "lightning neutrons" before responding.
Physics review letters good enough for you? "Strong Flux of Low-Energy Neutrons Produced by Thunderstorms"
http://prl.aps.org/abstract/PRL/v108/i12/e125001
Whether more lightning neutrons or cosmic ray neutrons reach the surface I think was speculation based on someone's back of the envelope calculation; similarly for whether neutrons are created by electron capture of temporarily overwhelmed hydrogen (most stable atoms will capture an electron if immersed in enough electrons, but will expel it again when the crisis is over; only hydrogen loses its atomic nature in this situation) or through D-D fusion. However already disproven are both spallation from lightning-created radiation, and lightning focussing of existing cosmic rays. Time and further research will tell.
And say what you will about "science establishing this or that", but strangely enough science merely asserts, and very often when dealing with natural rather than theoretical phenomena most of the assertions are just so much hot air. To be replaced next week by different hot air. Nature is complicated.
Most cosmic ray neutrons don't reach the surface of the earth. Lightning neutrons—which have been reported for decades but no one bothered to test for them until recently—form very near the surface and are very dense.
I'm a bit surprised people so willing to assert authority do so little to keep up. I'm also saddened that no one googled "lightning neutrons" before responding.
Physics review letters good enough for you? "Strong Flux of Low-Energy Neutrons Produced by Thunderstorms"
http://prl.aps.org/abstract/PRL/v108/i12/e125001
Whether more lightning neutrons or cosmic ray neutrons reach the surface I think was speculation based on someone's back of the envelope calculation; similarly for whether neutrons are created by electron capture of temporarily overwhelmed hydrogen (most stable atoms will capture an electron if immersed in enough electrons, but will expel it again when the crisis is over; only hydrogen loses its atomic nature in this situation) or through D-D fusion. However already disproven are both spallation from lightning-created radiation, and lightning focussing of existing cosmic rays. Time and further research will tell.
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Chris Bradley
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Re: FAQ - Why no neutrons exit atoms in natural decay processes
I've no idea what, or why, you are blithering on like this, but if you perform any neutron measurement at sea level you find there are enough around to measure a healthy signal with a sensitive enough detector.
Now, I can assure you that I've not seen any lightning around where I live in a real long time. So where are all these neutrons coming from that I can measure?
Muon flux at sea level is around 1 muon per cm^2/sec with a mean energy of 4 GeV (plenty enough energy to cause all sorts of trouble for an unsuspecting nucleus!), and are well known to be formed by cosmic ray bombardment of the upper atmosphere.
Now, I can assure you that I've not seen any lightning around where I live in a real long time. So where are all these neutrons coming from that I can measure?
Muon flux at sea level is around 1 muon per cm^2/sec with a mean energy of 4 GeV (plenty enough energy to cause all sorts of trouble for an unsuspecting nucleus!), and are well known to be formed by cosmic ray bombardment of the upper atmosphere.
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Carl Willis
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Re: FAQ - Why no neutrons exit atoms in natural decay processes
Production of neutrons by electron capture on hydrogen was distinctly YOUR idea, David. It's not supported by anything I've ever read (including the PRL paper you mention now, which instead offers a much more reasonable photonuclear hypothesis for lightning-generated neutrons). That's why I asked you about your source.
That most neutrons at Earth's surface have cosmogenic origin is not my idea either, but it is the mainstream understanding communicated in the field's references of first recourse, and as Chris points out it's consistent with even simple everyday hobby-style measurements of neutron background whereas lightning activity isn't. Quite a number of us have experience operating large, sensitive, neutron detectors. The origin of the neutron background isn't really a matter of speculation.
Lightning-related production of radiation (neutrons, terrestrial gamma-ray flashes, relativistic electrons, etc.) is an interesting subject, and the 2011 paper you cited is therefore interesting, but it doesn't deal with what you were talking about. Your assertions look like pseudoexpertise parading as definitive statements, something that will not make you my friend or probably anyone else's on this site.
Finally, you mention being saddened by people not googling "lightning neutrons". By "people" I suppose you mean me. Allow me to retort. Lightning neutrons have been discussed on this site before. I have posted a Nature paper about the subject here before. Years ago. Did you use the search feature?
Lame!
-Carl
That most neutrons at Earth's surface have cosmogenic origin is not my idea either, but it is the mainstream understanding communicated in the field's references of first recourse, and as Chris points out it's consistent with even simple everyday hobby-style measurements of neutron background whereas lightning activity isn't. Quite a number of us have experience operating large, sensitive, neutron detectors. The origin of the neutron background isn't really a matter of speculation.
Lightning-related production of radiation (neutrons, terrestrial gamma-ray flashes, relativistic electrons, etc.) is an interesting subject, and the 2011 paper you cited is therefore interesting, but it doesn't deal with what you were talking about. Your assertions look like pseudoexpertise parading as definitive statements, something that will not make you my friend or probably anyone else's on this site.
Finally, you mention being saddened by people not googling "lightning neutrons". By "people" I suppose you mean me. Allow me to retort. Lightning neutrons have been discussed on this site before. I have posted a Nature paper about the subject here before. Years ago. Did you use the search feature?
Lame!
-Carl
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DavidStewartZink
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Re: FAQ - Why no neutrons exit atoms in natural decay processes
[ I'm not sure what the lightning flux at your house (or whether you can see it) has to do with the global values. No doubt it is very cool at your house, so you know the arctic ice cannot possibly have melted. But it is certainly worth noting that both lightning & thermal neutron flux vary by location & season ]
I thought we were discussing neutron flux (not muons), which I understand to be around (5-10 / m^2 / s) from cosmogenic sources, or about (3-5 * 10^15 / Earth / s).
"Thermal" flux (i.e. the "summer" flux resulting from the chain outgassing of Radon etc => alpha-decay => alpha-bombardment => loose neutrons) has an annual average near 0/m^2/sec but will (in the right parts of the world) reach spiky peaks around 100/m^2/sec.
A single bolt of air-ground lightning seems to produce in excess of many millions of low energy neutrons which reach the surface. How many reach earth from air-air lightning or what the effects of positive versus negative lightning, or what curve connects neutrogenicity with stroke power I've seen no data on.
It's important to note that the scientists had failures at first measuring the numbers of neutrons produced because of concurrent arrivals being treated as single neutrons. Not certain what your techniques are like, but if you live in a lightning free zone it hardly matters.
You also need to be sensitive to low energy neutrons, of course.
There are only about 20 air-ground and 80 air-air lightning strokes per second globally, so production from an average single stroke of all types would need to exceed 5*10^13 in order for lightning to be the global leader. That probably doesn't happen. Globally. There should be locations and regions where the lightning neutron flux dominates the averages.
I thought we were discussing neutron flux (not muons), which I understand to be around (5-10 / m^2 / s) from cosmogenic sources, or about (3-5 * 10^15 / Earth / s).
"Thermal" flux (i.e. the "summer" flux resulting from the chain outgassing of Radon etc => alpha-decay => alpha-bombardment => loose neutrons) has an annual average near 0/m^2/sec but will (in the right parts of the world) reach spiky peaks around 100/m^2/sec.
A single bolt of air-ground lightning seems to produce in excess of many millions of low energy neutrons which reach the surface. How many reach earth from air-air lightning or what the effects of positive versus negative lightning, or what curve connects neutrogenicity with stroke power I've seen no data on.
It's important to note that the scientists had failures at first measuring the numbers of neutrons produced because of concurrent arrivals being treated as single neutrons. Not certain what your techniques are like, but if you live in a lightning free zone it hardly matters.
You also need to be sensitive to low energy neutrons, of course.
There are only about 20 air-ground and 80 air-air lightning strokes per second globally, so production from an average single stroke of all types would need to exceed 5*10^13 in order for lightning to be the global leader. That probably doesn't happen. Globally. There should be locations and regions where the lightning neutron flux dominates the averages.
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DavidStewartZink
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Re: FAQ - Why no neutrons exit atoms in natural decay processes
Not to critique your reading comprehension, but the PRL paper REFUTES the photo-nuclear hypothesis.
"The low-energy neutron flux value obtained in our work is a challenge for the photonuclear channel of neutron generation in thunderstorm: the estimated value of the needed high-energy γ-ray flux is about 3 orders of magnitude higher than that one observed."
"The low-energy neutron flux value obtained in our work is a challenge for the photonuclear channel of neutron generation in thunderstorm: the estimated value of the needed high-energy γ-ray flux is about 3 orders of magnitude higher than that one observed."
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DavidStewartZink
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Re: FAQ - Why no neutrons exit atoms in natural decay processes
CW: "The origin of the cosmic secondary neutrons is not explained by electron capture on hydrogen"
DSZ: "Of course cosmic rays don't produce neutrons through electron capture, that's a silly idea, and also: yours."
CW: "Production of neutrons by electron capture on hydrogen was distinctly YOUR idea, David."
Seriously?
DSZ: "Of course cosmic rays don't produce neutrons through electron capture, that's a silly idea, and also: yours."
CW: "Production of neutrons by electron capture on hydrogen was distinctly YOUR idea, David."
Seriously?
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Chris Bradley
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Re: FAQ - Why no neutrons exit atoms in natural decay processes
David Stewart Zink wrote:
> I'm not sure what the lightning flux at your house ...has to do with the global values.
....because neutrons made 'globally', miles away, are not going to make it to my house for me to measure. The neutrons will thermalise before getting here and have insufficient energy, nor lifetime, to make the distance. 50% of the neutrons I measure were made locally in the previous 611 seconds .... more than 99.9% of them were made nearby in the last 2 hours.
> I thought we were discussing neutron flux (not muons)
..yes, neutrons which are made by muon bombardments....
Can I ask you, do you think it is better to learn something about the subject you are hoping to discuss, before trying to discuss it?
I think there is a lump of posts here that might be better deleted, as this is meant to be a FAQ.
> I'm not sure what the lightning flux at your house ...has to do with the global values.
....because neutrons made 'globally', miles away, are not going to make it to my house for me to measure. The neutrons will thermalise before getting here and have insufficient energy, nor lifetime, to make the distance. 50% of the neutrons I measure were made locally in the previous 611 seconds .... more than 99.9% of them were made nearby in the last 2 hours.
> I thought we were discussing neutron flux (not muons)
..yes, neutrons which are made by muon bombardments....
Can I ask you, do you think it is better to learn something about the subject you are hoping to discuss, before trying to discuss it?
I think there is a lump of posts here that might be better deleted, as this is meant to be a FAQ.
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Carl Willis
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- Location: Albuquerque, New Mexico, USA
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Re: FAQ - Why no neutrons exit atoms in natural decay processes
Not quite.
"It means that neutrons observed during the enhancement
event are generated in the air and in the upper layer of
the ground, what may indicate the possibility for neutrons
to be born in photonuclear process by rays generated in
atmospheric discharge." (p. 4)
The rest of p. 4 is the author's discussion about extremely limited data on photon fluxes in and around thunderstorms, and to be fair to you, yes, the point that his measurement challenges the photonuclear hypothesis in the context of the limited findings of one other experiment. It's not fair to call this a "refutation" of the only hypothesis the author actually advances; it's better to say that he calls attention to a reasonable hypothesis, noting that it isn't entirely consistent with spare data from a single other source.
You also want to pick a bone with me about who said what, further up this same thread. I think where you're missing the point of something I wrote has to do with a syntactical lack of clarity in one of my sentences. So let's rephrase my point in a way that gets that manufactured non-issue out of the way. My point is that you said two things, one about the source of most earthly free neutrons, and something else about how they probably come from electron capture, and neither has any attribution to a reliable source, nor is either commonly held to be true in my field. So my point was, and is, that I would like to see your source for those assertions. Very simple, really.
Our experimental hobby fusion community welcomes all honest and respectful comers who want to contribute from their own experience. Chest-thumping wars and pseudoexpertise dropped on a FAQ thread is an inauspicious beginning, though. Let's wrap this nonsense up and move on.
-Carl
"It means that neutrons observed during the enhancement
event are generated in the air and in the upper layer of
the ground, what may indicate the possibility for neutrons
to be born in photonuclear process by rays generated in
atmospheric discharge." (p. 4)
The rest of p. 4 is the author's discussion about extremely limited data on photon fluxes in and around thunderstorms, and to be fair to you, yes, the point that his measurement challenges the photonuclear hypothesis in the context of the limited findings of one other experiment. It's not fair to call this a "refutation" of the only hypothesis the author actually advances; it's better to say that he calls attention to a reasonable hypothesis, noting that it isn't entirely consistent with spare data from a single other source.
You also want to pick a bone with me about who said what, further up this same thread. I think where you're missing the point of something I wrote has to do with a syntactical lack of clarity in one of my sentences. So let's rephrase my point in a way that gets that manufactured non-issue out of the way. My point is that you said two things, one about the source of most earthly free neutrons, and something else about how they probably come from electron capture, and neither has any attribution to a reliable source, nor is either commonly held to be true in my field. So my point was, and is, that I would like to see your source for those assertions. Very simple, really.
Our experimental hobby fusion community welcomes all honest and respectful comers who want to contribute from their own experience. Chest-thumping wars and pseudoexpertise dropped on a FAQ thread is an inauspicious beginning, though. Let's wrap this nonsense up and move on.
-Carl
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Dan Tibbets
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Re: FAQ - Why no neutrons exit atoms in natural decay processes
David, before others chip in on your misconceptions. Let me make some points. The cosmic rays are not neutrons. Mostly, they are protons. It is not neutrons falling to earth, nor is it electron capture. It is is a pure hammer approach. The kinetic energy of the cosmic ray particles is so high ( over a few MeV, they are atom smashers. They literally tear the target (and possibly themselves) apart. A shower of particles- muons, protons, neutrons, etc are produced.
Google atom smasher, particle accelerators, the Oppenheiner (sp?) effect, etc.
Electron capture can happen in hydrogen, but it is an incredibly rare event, even in the core of the Sun. The cross section is ~ 10^-45 .
In comparison hot deuterium fusion has a cross section of ~ 10^-27, A billion billion times more likely.
Despite cold fusion claims , I know of no evidence for this occurring outside of very dense and hot environments like the core of the Sun.
There is electron captures that occur at significant rates, but this is mostly in heavier elements in the incredibly hot environments of super nova explosions.
Dan Tibbets
Google atom smasher, particle accelerators, the Oppenheiner (sp?) effect, etc.
Electron capture can happen in hydrogen, but it is an incredibly rare event, even in the core of the Sun. The cross section is ~ 10^-45 .
In comparison hot deuterium fusion has a cross section of ~ 10^-27, A billion billion times more likely.
Despite cold fusion claims , I know of no evidence for this occurring outside of very dense and hot environments like the core of the Sun.
There is electron captures that occur at significant rates, but this is mostly in heavier elements in the incredibly hot environments of super nova explosions.
Dan Tibbets
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Richard Hull
- Moderator
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- Real name: Richard Hull
Re: FAQ - Why no neutrons exit atoms in natural decay processes
I hope my last word on this as this post morphs from its original theme of "little to no natural isotopic matter decay neutron emission" to earthly neutron sources.
If there is no thunderstorm in your immediate area, right now, you will measure 0.000000 lightning based neutrons. The neutrons or shall I say the "detection events" in a large volume, sea level based 3He detector are mostly from neutrons created at or near the surface or tube wall/gas events caused by cosmic rays that have made it through the atmosphere or other local, to the detector, cosmogenic events whereby freshly created particles of huge energy are reacting with the tube or gas. Due to a well adjusted discriminator, We can warrant that most events will be neutronic in nature, but when a 10-100mev particle hits the tube wall and stars into the gas, it will be detected! a carefully watched DSO hooked to the output of the tube's preamp will show neutrons versus cosmogenic events as pulse heights that are amazing compared to normal neutron detects.
For our data collecting purposes it is all background. A background that we must subtract from any fusor operational efforts. Whether every background event in our detectors is a neutron of not is of no significance, but we can be sure that anything above this background is a neutron based on a fusion event within our fusors.
For my large 3He detector which is not massive, but just large, I regularly measure only 5-8 events per minute, background, and have recorded a near doubling of this at certain times after a very large CME event on the sun.
If there is no thunderstorm in your immediate area, right now, you will measure 0.000000 lightning based neutrons. The neutrons or shall I say the "detection events" in a large volume, sea level based 3He detector are mostly from neutrons created at or near the surface or tube wall/gas events caused by cosmic rays that have made it through the atmosphere or other local, to the detector, cosmogenic events whereby freshly created particles of huge energy are reacting with the tube or gas. Due to a well adjusted discriminator, We can warrant that most events will be neutronic in nature, but when a 10-100mev particle hits the tube wall and stars into the gas, it will be detected! a carefully watched DSO hooked to the output of the tube's preamp will show neutrons versus cosmogenic events as pulse heights that are amazing compared to normal neutron detects.
For our data collecting purposes it is all background. A background that we must subtract from any fusor operational efforts. Whether every background event in our detectors is a neutron of not is of no significance, but we can be sure that anything above this background is a neutron based on a fusion event within our fusors.
For my large 3He detector which is not massive, but just large, I regularly measure only 5-8 events per minute, background, and have recorded a near doubling of this at certain times after a very large CME event on the sun.
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Steven Sesselmann
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- Real name: Steven Sesselmann
- Location: Sydney - Australia
- Contact:
Re: FAQ - Why no neutrons exit atoms in natural decay processes
?
Am I missing something in this thread...., why would a neutron be kicked out of a stable nucleus?
There is no Coulomb repulsion between the neutron and the other nucleons, so what if anything would kick it out and why?
In the case of fusion neutrons, I think there is a simpler explanation.
When two deuterons are captured in each others cross section, the angular velocity around each other may increase to a point where bits literally fall off, sometimes it is a neutron and sometimes it is a proton. A slingshot effect, similar to that used by spacecraft, to gain additional velocity by moving in a close rendezvous with a planet.
Steven
Am I missing something in this thread...., why would a neutron be kicked out of a stable nucleus?
There is no Coulomb repulsion between the neutron and the other nucleons, so what if anything would kick it out and why?
In the case of fusion neutrons, I think there is a simpler explanation.
When two deuterons are captured in each others cross section, the angular velocity around each other may increase to a point where bits literally fall off, sometimes it is a neutron and sometimes it is a proton. A slingshot effect, similar to that used by spacecraft, to gain additional velocity by moving in a close rendezvous with a planet.
Steven
http://www.gammaspectacular.com - Gamma Spectrometry Systems
https://www.researchgate.net/profile/Steven_Sesselmann - Various papers and patents on RG
https://www.researchgate.net/profile/Steven_Sesselmann - Various papers and patents on RG