Influencing Beta Decay: Electron & Neutrino Density Effects

[sanman]

Because electrons are known to be participants in the beta-decay reaction, electron density has been shown to influence the rate of beta decay:

http://prl.aps.org/abstract/PRL/v98/i25/e252501

http://www.phys.ncku.edu.tw/mirrors/physicsfaq/ParticleAndNuclear/decay_rates.html

http://www.hps.org/publicinformation/ate/q7843.html

the most dramatic radionuclide in this regard has been rhenium-187, for which a remarkable reduction in the half-life from 4.1 x 10^10 years to about 33 years has been observed.

So how could this be used for practical purposes?

I've read about beta-batteries being used for applications where you want a long-lived power source. But how much current are they capable of supplying?

In situations where electron density influences rate of beta decay, then since electron density can be dynamically adjusted, then does this mean that beta-decay rates can likewise be dynamically adjusted on the fly?

Since neutrinos are also participants in beta-decay, then could neutrino density similarly affect beta-decay rate? Could suitable beta-decay reaction isotope species then be the basis for a neutrino detector?

Beta-decay then allows the electronic world to overlap with the nuclear world.
But like that story of passing a camel through the eye of a needle, does beta-decay likewise influence any other nuclear processes - like alpha-decay, for example?

 

[sanman]

Further on the subject of neutrino detection, this was an interesting article from a few years ago:

http://physicsworld.com/cws/article/news/36108

Even if the decay-rate correlations with solar flares and the Earth–Sun distance are more than a coincidence, they raise the question of precisely what solar activity is causing the effect. In a more recent paper submitted to Physical Review Letters (preprint at arXiv:0808.3283), the Purdue researchers suggest that the radioactive nuclei are somehow affected by solar neutrinos.

...

Meanwhile, the Purdue researchers have just found yet another example of the decay-rate annual modulation — this time by a US paediatrician who was investigating the decay of plutonium–238–beryllium in 1990. “What our data are showing is that the half lives, or the decay constants, are apparently not fundamental constants of nature, but appear to be affected by solar activity,” says Fischbach. “To summarize, what we are showing is that the decay constant is not really a constant.”

http://www.npl.washington.edu/AV/altvw147.html

 

[Creator]

Because electrons are known to be participants in the beta-decay reaction, electron density has been shown to influence the rate of beta decay:

http://prl.aps.org/abstract/PRL/v98/i25/e252501

http://www.phys.ncku.edu.tw/mirrors/physicsfaq/ParticleAndNuclear/decay_rates.html

http://www.hps.org/publicinformation/ate/q7843.html

Thanks Sanman; for bringing up an important topic which not too many are willing to discuss...
Its always humbling when one realizes an error has been taught for so many years...and in this case sometimes there seems to be an avoidance of this topic for the same reason.

My opinion is that the decay rates may be found to have some sort of dependence upon quantum fluctuations that seem to vary with gravitational (acceleration) potential.
We know that in QED spontaneous emission is at least in part due to quantum fluctuations.
Suppression (and promotion) of excited atomic decay rates are now commonly obtained within Casimir cavities, implying a quantum fluctuation connection...and possibly your links describing rate changes via surrounding "enclosures" is related to the same type of vacuum energy density variation (rather than 'electron density' per se.)

IMHO, I think we may be seeing the beginning of a quantum fluctuation connection to gravitational potential.
Small seasonal decay rate variations have been found recently which point to variations correlated with Earth - sun distance. They are real rate variations; However, I don't agree with Fischbach, et al, that they may be due to neutrino flux; rather I think they are inherent in gravitational variations via changes in vacuum fluctuations.

Here's another report in that regard which seems to re-enforce my opinion of 'non-inertial' rate dependence.

http://www.springerlink.com/content/x1q13217t2427059/

Interesting stuff.

Creator

 

[sanman]

Hey, thanks for that link! Nice find!
Are these results legit? Has anybody reproduced them?

The summary ends with:

It is suggested that these effects may be caused by the chiral interaction.

What is the "chiral interaction"?
That phrase doesn't sound like it has anything to do with vacuum fluctuations.

Does the arrangement of nucleons in the nucleus have any chiral properties?
I never realized there could be such a thing, analogous to the arrangement of molecular constituents due to electronic bonding.

 

[Bob S]

I've read about beta-batteries being used for applications where you want a long-lived power source. But how much current are they capable of supplying?

A 1 Curie source of betas (3.7 x 10¹⁰ decays per second) can supply a current of about 5.9 nano amps, at voltages (beta energies) of ~100's of kilovolts. So it is not a good direct substitute for batteries. A 1 Curie beta source (with gammas) is lethal unless shielded with lots of lead.

Bob S

 

[bcrowell]

Thanks Sanman; for bringing up an important topic which not too many are willing to discuss...
Its always humbling when one realizes an error has been taught for so many years...and in this case sometimes there seems to be an avoidance of this topic for the same reason.

You're confused. It's been known for many decades that electron capture depends on the electronic environment. There has been no error taught about this in general, although it's certainly possible that people who understand the effect might nevertheless speak or write carelessly and forget to add caveats about its existence.

My opinion is that the decay rates may be found to have some sort of dependence upon quantum fluctuations that seem to vary with gravitational (acceleration) potential.
We know that in QED spontaneous emission is at least in part due to quantum fluctuations.
Suppression (and promotion) of excited atomic decay rates are now commonly obtained within Casimir cavities, implying a quantum fluctuation connection...and possibly your links describing rate changes via surrounding "enclosures" is related to the same type of vacuum energy density variation (rather than 'electron density' per se.)

Please see PF's rules about overly speculative posts: https://www.physicsforums.com/showthread.php?t=5374

IMHO, I think we may be seeing the beginning of a quantum fluctuation connection to gravitational potential.
Small seasonal decay rate variations have been found recently which point to variations correlated with Earth - sun distance. They are real rate variations; However, I don't agree with Fischbach, et al, that they may be due to neutrino flux; rather I think they are inherent in gravitational variations via changes in vacuum fluctuations.

The Fischbach result is bogus. See http://arxiv.org/abs/0809.4248

Here's another report in that regard which seems to re-enforce my opinion of 'non-inertial' rate dependence.

http://www.springerlink.com/content/x1q13217t2427059/

He YuJian is a crank; for something even sillier by the same author: http://english.cas.cn/Ne/CASE/200509/t20050915_17173.shtml Here is a later result that showed that He YuJian's result was not reproducible: http://www.springerlink.com/content/l462l03732453667/

[EDIT: Oops, above I originally used the term "electron conversion," when I should have said "electron capture." They're two totally different things, and I referred to the wrong one.]

 

[bcrowell]

Apparently there is quite a cottage industry on this topic. I've written up a FAQ.

FAQ: Do rates of nuclear decay depend on environmental factors?

There is one environmental effect that has been scientifically well established for a long time. In the process of electron capture, a proton in the nucleus combines with an inner-shell electron to produce a neutron and a neutrino. This effect does depend on the electronic environment, and in particular, the process cannot happen if the atom is completely ionized.
Other claims of environmental effects on decay rates are crank science, often quoted by creationists in their attempts to discredit evolutionary and geological time scales.
He et al. (He 2007) claim to have detected a change in rates of beta decay of as much as 11% when samples are rotated in a centrifuge, and say that the effect varies asymmetrically with clockwise and counterclockwise rotation. He believes that there is a mysterious energy field that has both biological and nuclear effects, and that it relates to circadian rhythms. The nuclear effects were not observed when the experimental conditions were reproduced by Ding et al.
Jenkins and Fischbach claim to have observed effects on alpha decay rates correlated with an influence from the sun. They proposed that their results could be tested more dramatically by looking for changes in the rate of alpha decay in radioisotope thermoelectric generators aboard space probes. Such an effect turned out not to exist (Cooper 2009).
Cardone et al. claim to have observed variations in the rate of alpha decay of thorium induced by 20 kHz ultrasound, and claim that this alpha decay occurs without the emission of gamma rays. Ericsson et al. have pointed out multiple severe problems with Cardone's experiments.
He YuJian et al., Science China 50 (2007) 170.
YouQian Ding et al., Science China 52 (2009) 690.
Jenkins and Fischbach (2008), http://arxiv.org/abs/0808.3283v1
Jenkins and Fischbach (2009), http://arxiv.org/abs/0808.3156
Cooper (2009), http://arxiv.org/abs/0809.4248
F. Cardone, R. Mignani, A. Petrucci, Phys. Lett. A 373 (2009) 1956
Ericsson et al., Comment on "Piezonuclear decay of thorium," Phys. Lett. A 373 (2009) 1956, http://arxiv4.library.cornell.edu/abs/0907.0623
Ericsson et al., http://arxiv.org/abs/0909.2141

[EDIT: Oops, above I originally used the term "electron conversion," when I should have said "electron capture." They're two totally different things, and I referred to the wrong one.]

 

[sanman]

Let's Play with Beta Decay!

It's been known for many decades that electron conversion decay depends on the electronic environment. There has been no error taught about this in general, although it's certainly possible that people who understand the effect might nevertheless speak or write carelessly and forget to add caveats about its existence.

So then EM can be used to modulate the Weak force? This would allow us to modulate the beta decay rate, wouldn't it? And doesn't that imply a direct means of neutrino/antineutrino production, using electrons or electromagnetic force?

Like that story of passing the camel through the eye of the needle, can't we use electrons to accelerate beta decay, to stimulate neutrino production or even encourage neutrino absorption?

If a heavy nucleus (eg. Rhenium-187) stripped of its electrons then tends to undergo faster beta-decay, could neutrons surrounded by high enough electronic charge then be given longer lifespans?

Let's say we've got a long straight carbon nanotube, which we can use as a conduit. Let's also make it a multi-wall carbon nanotube, so that its exterior surface area or circumference is significantly greater than its interior surface area or circumference. If we apply an appropriate field or charge on the outer surface of our MWNT, then we can radially polarize it, causing charge to migrate inwards and concentrate at the nanotube's interior. Lots of delocalized electrons among the SP2-hybridized carbons of that MWNT to assist in charge migration, allowing charge to concentrate at the center, like an "hydraulic effect".

We fire a neutron down the interior corridor of this nanotube. We then turn off the radial polarization to remove the charge concentration at the interior. We then fire another neutron down the same corridor. Which neutron will in theory travel farther, before decaying into a proton? Will their travel distance before decay be identical? Or will there be a difference?

Anybody have an answer, or a guess? bcrowell? anyone?

 

[bcrowell]

So then EM can be used to modulate the Weak force?

No. Please learn what electron capture is before you start making wild speculation: http://en.wikipedia.org/wiki/Electron_capture

[EDIT: Oops, above I used the term "electron conversion," when I should have said "electron capture." They're two totally different things, and I used the wrong one.]

 

[sanman]

No. Please learn what internal conversion is before you start making wild speculation: http://en.wikipedia.org/wiki/Internal_conversion

Hmm, well you're talking about internal conversion, while I was talking about beta-decay.
See my first 3 links posted in this thread.

He YuJian may be a crank, but Ohtsuki is not.

So if beta decay can be accelerated, why can't it be decelerated as well - even if only marginally?

 

[sanman]

No. Please learn what electron capture is before you start making wild speculation: http://en.wikipedia.org/wiki/Electron_capture

[EDIT: Oops, above I used the term "electron conversion," when I should have said "electron capture." They're two totally different things, and I used the wrong one.]

Ah, okay, so I've read the link on electron capture - thanks for that.

In this case, one of the orbital electrons, usually from the K or L electron shell (K-electron capture, also K-capture, or L-electron capture, L-capture), is captured by a proton in the nucleus, forming a neutron and a neutrino.

p + e⁻ → n + νe

Note that a free proton cannot normally be changed to a free neutron by this process. The proton and neutron must be part of a larger nucleus

So how much of a nucleus do they have to be part of?
If you use a lighter nucleus (eg. tritium) as compared to some really heavy nucleus, is the electron capture effect more pronounced? Does it prefer certain ratios of protons to neutrons, or is it that the more baryons in general that there are, the more the electron capture process can take place?

If we do the experiment I suggested above, but firing nuclei of different masses down the MWNT instead of just the lone neutrons, then will we see differences in the distance traveled before decay takes place?

Is there an explanation of why the electron capture reaction only occurs inside of a nucleus, as opposed to a free proton? Is it that W and Z bosons don't exist outside of proton-neutron combines? Is the Strong force a mediator for the Weak force?

What is the key difference here between being in a nucleus and not being in a nucleus, that allows electron capture to take place?

 

[bcrowell]

Hmm, well you're talking about internal conversion, while I was talking about beta-decay.
See my first 3 links posted in this thread.

Actually I meant electron capture, not internal conversion, but that was my mistake for using the wrong term. Anyway, electron capture is closely related to beta decay. It occurs via the weak force, and it's the same Feynman vertex as beta decay, just with one forward-going particle changed into a backward-going one.

He YuJian may be a crank, but Ohtsuki is not.

Are you referring to this? http://prl.aps.org/abstract/PRL/v98/i25/e252501 This is a paper about electron capture. There is no controversy about the fact that electron capture can depend on the electronic environment.

So if beta decay can be accelerated, why can't it be decelerated as well - even if only marginally?

Electron capture can. Other forms of beta decay can't.

Is there an explanation of why the electron capture reaction only occurs inside of a nucleus, as opposed to a free proton?

Conservation of energy. Try computing the mass-energy balance for decay of a hydrogen atom by electron capture.

You need to get more of a handle on the basic physics before you start in on all the wild speculation.

 

[sanman]

Stimulating Beta Decay

Okay, so I then return back to my original questions - how can the modulation of beta-decay rate be usefully exploited? It seems pretty obvious that we can modulate electron density around radionuclides - such as by using MWNT or C60, for example. So therefore, we ought to be able to modulate beta-decay rates as well.

So then it's a matter of finding some utility in doing this.

Beta-decay could then release significant nuclear energy for us on demand, if we could speed it up at will. And this energy would be in the form of transmuted radionuclides of lower atomic number, which as charged particles could be harvested with reasonable efficiency.

So if we could pipette the right radionuclides through our radially polarized MWNTs having a high electronic charge density at their interior, then we could create a bias in favor of the electron capture beta decay reaction, transmuting those radionuclides and yielding energy in the process. Oh, and neutrinos too.

Intuitively, I would think that the shorter the half-life of the radionuclide, the more susceptible it would be to beta-decay stimulus. After all, the half-life is a statistical measure of susceptibility to beta-decay.

I wonder if the transmuted nucleus product gets kinetic energy in any arbitrary direction, or if there's a way to ensure that it moves in a particular direction.

 

[Vanadium 50]

Okay, so I then return back to my original questions - how can the modulation of beta-decay rate be usefully exploited?

It can't.

Ignoring the crankery, if you want to make a noticeable change in decay rate, you need to make a huge impact on the surrounding electron environment: for example, stripping off all 75 electrons in a rhenium atom. This takes a lot of energy - hundreds of keV or more, which is comparable to the energy in beta decay processes.

Trying to influence it with chemistry-sized processes - a million times smaller - is hopeless.

 

[sanman]

It can't.

Ignoring the crankery, if you want to make a noticeable change in decay rate, you need to make a huge impact on the surrounding electron environment: for example, stripping off all 75 electrons in a rhenium atom. This takes a lot of energy - hundreds of keV or more, which is comparable to the energy in beta decay processes.

Trying to influence it with chemistry-sized processes - a million times smaller - is hopeless.

But that's like saying, "You can never use electromagnetic/chemical forces to liberate net energy from the Strong force, because it just takes too much energy. Even if you can build a soccerball-shaped explosive to compress things electromagnetically, it costs too much to detonate one around each and every atom"

Well, of course we don't build and detonate one around each and every atom, we just build and detonate one around that whole critical mass of heavy atoms having sufficient nuclear cross-section.

Likewise, is it not possible that we can surround not one but many atoms with a region of higher electron density, or powerful EM field, and achieve some economy of scale by surrounding the many nuclei together instead of the one?

Is chain reaction possible? What is the critical mass for neutrino capture or electron capture, respectively? What is the minimum nuclear cross-section for neutrino capture or electron capture, respectively?

If electromagnetism can release net energy from the strong force through fission, then why can't electromagnetism release net energy from the weak force through beta-decay, in principle? With fission, we talk about "neutron economics", and so with beta-decay we'd talk about "electron economics" or "neutrino economics". Is there some point at which the economics of beta chain reaction are sustainable/favorable - even for brief moments? Is there some theoretical critical density at which this could happen? (ie. mass density? electron density or field strength? neutrino density? etc)

 

[bcrowell]

Ignoring the crankery, [...]

Aw, shucks, but that would mean giving up the whole thread.

 

[sanman]

Aw, shucks, but that would mean giving up the whole thread.

Heh, everybody's a critic and a skeptic, but not enough people come up with new suggestions for energy.

I was trying to point out and look at ways to usefully harness beta decay for energy production. If our well-known workhorse electrons participate in beta decay reactions through electron capture, then they could be put to the task of extracting energy from the beta decay process - with the caveat that they must be inner electrons interacting with protons in a bound state, as you've mentioned.

So if we can devise all kinds of high-energy fusion devices in the hopes of extracting even more energy than they use up, then why can't we look at ways to apply energy to stimulate the release of even more energy via beta decay?

Nobody has even thought of a practical way to come up with enough tritium to sustain a fusion reactor in its early period of operation, and don't forget that it would also release some neutron radiation. But what does beta decay really cost us?

We owe it to ourselves to look more closely at beta decay, to find out if we can get more out of it than we currently do.

 

[Vanadium 50]

We owe it to ourselves to look more closely at beta decay, to find out if we can get more out of it than we currently do.

As Tonto once said, "What you mean 'we', white man?"

The fact that you don't understand the weak interaction - as evidenced by your wild speculation that it behaves in ways that it demonstrably does not (such as a chain reaction) - doesn't mean that nobody understands it.

 

[sanman]

Alright, fair enough - I was only asking whether it could, not asserting that it could.

At one time, it was thought that the rate of decay could not be influenced, but we now know that it can be. Electrons are well-known workhorse particles of science and technology - we have a pretty good knowledge of how to manipulate and use them. Since electrons are participants in beta decay, this offers the opportunity to use them for investigating the beta decay reaction in more exhaustive detail, to look for a potential opportunity to exploit it.

A significant number of people believe that the Polywell approach to fusion energy could work. How much more difficult would it be to attempt an electrostatic approach to accelerating beta decay, to liberate usefully large amounts of energy from it?