Widom Larsen (WL-) Theory, LENR, CF (Rossi, etc)

[Giorgio]

What do you mean?
You want to know the method of gamma ray emission or you want to know the reason for the emission of the gamma?

Why does there have to be a gamma emission? What is it that REQUIRES there to be a gamma?

Maybe I am not focusing the real meaning of your question.

When a nucleus undergoes Alpha or Beta decay it generally becomes unstable and in an exited state. To go back to ground state it has to loose energy and does that by emitting Gamma.

I hope that was the point of your question.

[rjaypeters]

i dont know. is there? thinking of a raiding party to go steal all their knowledge? or just trolling

None of the above. At one hundred pages, and counting, perhaps the subject deserves its own forum?

[KitemanSA]

When a nucleus undergoes Alpha or Beta decay it generally becomes unstable and in an exited state. To go back to ground state it has to loose energy and does that by emitting Gamma.

I hope that was the point of your question.

First, we were talking about absorbing a neutron, not alpha or beta decay.
Second, and again, this is a statement that it somehow magically DOES, not WHY it does. (Sorry about the "magically", but sometimes...)
What makes it so that is HAS to? There is perhaps an indication in your statement (energy release) by not a real answer.
Third, based on what source of information did everyone decide that it HAS to?

[Giorgio]

When a nucleus undergoes Alpha or Beta decay it generally becomes unstable and in an exited state. To go back to ground state it has to loose energy and does that by emitting Gamma.

I hope that was the point of your question.

First, we were talking about absorbing a neutron, not alpha or beta decay.
Second, and again, this is a statement that it somehow magically DOES, not WHY it does. (Sorry about the "magically", but sometimes...)
What makes it so that is HAS to? There is perhaps an indication in your statement (energy release) by not a real answer.
Third, based on what source of information did everyone decide that it HAS to?

Ok, let me restate that.

Thermal neutrons tend to be easily absorbed by a nucleus they come in contact with and, as a consequence, they form an unstable isotope.
The unstable isotope spontaneously tend to decay by Alpha or Beta emission.
After this decay the nucleus is still in excited state and to get back to ground state it has to emit yet more energy.
He does this by emission of Gamma.

We do know because is experimentally tested and proven.

[KitemanSA]

Thermal

As in keV? So they have, in your example, substantial momentum. Hmm. WL doesn't have this.

neutrons tend to be easily absorbed by a nucleus they come in contact with and, as a consequence, they form an unstable isotope.

And if another is absorbed by said unstable isotope before it decays?

The unstable isotope spontaneously tend to decay by Alpha or Beta emission.

After a goodly time (relative to the scales we are talking about) no?

After this decay the nucleus is still in excited state and to get back to ground state it has to emit yet more energy.
He does this by emission of Gamma.

ONLY? EVER? In EVERY possible condition conceiveable?

We do know because is experimentally tested and proven.

In what conditions? What is the SOURSE of the information? Were the experiments carried out in similar conditions to Rossi's reator or something totally different?

And in a related question, you seem to state that this happens AFTER α or β decay, but the statements were "prompt gamma emmision". This doesn't seem very "prompt". Are you sure you are answering MY question and not a different one?

[MSimon]

And if another is absorbed by said unstable isotope before it decays?

The probability of this is rather low in ordinary circumstances. And even if the probability was high there ought to be some leakage if the reaction rate is high enough. i.e. out of 1E12 reactions a second shouldn't we see see something like 1E4 (or more) particles emitted?

And what about those situations where adding another neutron makes the atom MORE radioactive? Why aren't we seeing that?

Or do we have a bunch of Maxwell Demons running around and checking that only reactions that emit no particles or radiation are allowed?

As I understand it the chemicals used are not semiconductor grade - 5 or 6 nines pure. At best they are 3 nines. So why aren't we seeing radiation from neutron capture by the impurities?

[Giorgio]

Thermal

As in keV? So they have, in your example, substantial momentum. Hmm. WL doesn't have this.

We are talking about very low energy here 0.0253 eV:
http://www.euronuclear.org/info/encyclo ... hermal.htm
They normally reach this value after bouncing around a couple of dozen of time.

neutrons tend to be easily absorbed by a nucleus they come in contact with and, as a consequence, they form an unstable isotope.

And if another is absorbed by said unstable isotope before it decays?

I guess it forms another isotope even less stable. Probably some of the particle physics here can reply to this.

The unstable isotope spontaneously tend to decay by Alpha or Beta emission.

After a goodly time (relative to the scales we are talking about) no?

It should be instantaneous even at their time scale. I remember something in the range of 10^-14 sec or 10^-12 sec, can't remember the exact value right now.

After this decay the nucleus is still in excited state and to get back to ground state it has to emit yet more energy.
He does this by emission of Gamma.

ONLY? EVER? In EVERY possible condition conceiveable?

As far as I know yes.
Than again, a particle physics could tell us if there are exceptions.

We do know because is experimentally tested and proven.

In what conditions? What is the SOURSE of the information? Were the experiments carried out in similar conditions to Rossi's reator or something totally different?

This is basic nuclear physics. These type of info are known since we have started to split the atom.
I think you refer to the declaration of Rossi that there are gamma rays leaking out of an unshielded reactor. That info tells us nothing, as we have no idea about the spectra of the gamma.

And in a related question, you seem to state that this happens AFTER α or β decay, but the statements were "prompt gamma emmision". This doesn't seem very "prompt". Are you sure you are answering MY question and not a different one?

It depends if you consider 10^-14 sec to be enough prompt or not.
Additionally I am still having difficulties trying to understand what is the issue you are trying to explore.

[KitemanSA]

And if another is absorbed by said unstable isotope before it decays?

The probability of this is rather low in ordinary circumstances. And even if the probability was high there ought to be some leakage if the reaction rate is high enough. i.e. out of 1E12 reactions a second shouldn't we see see something like 1E4 (or more) particles emitted?

And what about those situations where adding another neutron makes the atom MORE radioactive? Why aren't we seeing that?

Or do we have a bunch of Maxwell Demons running around and checking that only reactions that emit no particles or radiation are allowed?

As I understand it the chemicals used are not semiconductor grade - 5 or 6 nines pure. At best they are 3 nines. So why aren't we seeing radiation from neutron capture by the impurities?

Wonderful. Latch onto an aside and don't answer my basic question.

Why MUST there be a gamma emission? So far, there has been a lot of talk about OTHER conditions but not much about this stuff. Why gamma? Why not 10 X-ray? How bout 100UV? Could the presence of a lot of close by H cause different nuclear oscillations that don't support gamma emission? How bout none at all? Maybe the energy is redistributed thru coulomb excitation of nearby H. We are talking DIFFERENT conditions here. You can't take the lessons learned from vacuumn tubes and apply them blindly to transistors. Different physics.

So I ask again, why MUST there be a gamma emission?

[MSimon]

In what conditions? What is the SOURSE of the information? Were the experiments carried out in similar conditions to Rossi's reator or something totally different?

Kiteman,

You are really clutching at straws here. Really.

What you are saying in effect is that in the Rossi reactor particle reactions work completely differently than they do every where else that we have tested.

This may be so. But it is so unlikely given the last 60 years of work on the subject you are going to need much better evidence than I have seen so far.

"We have a device that induces 1E12 nuclear reactions a second (or more) that gives off no detectable radiation." Maybe.

Maybe it is all neutrinos. How does that happen?

[Giorgio]

So I ask again, why MUST there be a gamma emission?

Because this is the way it works.

If you want to know why nature decided to emit gamma instead of something else in that situation I doubt someone can reply.

[MSimon]

I guess I should be following this more closely, but wasn't one of Rossi's selling points : "no radiation?" Certified by some authority? Or was that some other experimenter?

As to gamma shielding - you have an extinction ratio - a certain thickness will reduce the gamma flux by a factor of 10. It is not like shielding against bullets.

How thick was Rossi's shield? What energy gamma/X-ray was he shielding against?

[Giorgio]

I guess I should be following this more closely, but wasn't one of Rossi's selling points : "no radiation?" Certified by some authority? Or was that some other experimenter?

As to gamma shielding - you have an extinction ratio - a certain thickness will reduce the gamma flux by a factor of 10. It is not like shielding against bullets.

How thick was Rossi's shield? What energy gamma/X-ray was he shielding against?

He has 2cm lead shielding.
As for the gamma energy he always refused anyone to measure it, stating that once the spectra was known the whole process will become clear.
That of course means anything and nothing.

[MSimon]

I guess I should be following this more closely, but wasn't one of Rossi's selling points : "no radiation?" Certified by some authority? Or was that some other experimenter?

As to gamma shielding - you have an extinction ratio - a certain thickness will reduce the gamma flux by a factor of 10. It is not like shielding against bullets.

How thick was Rossi's shield? What energy gamma/X-ray was he shielding against?

He has 2cm lead shielding.
As for the gamma energy he always refused anyone to measure it, stating that once the spectra was known the whole process will become clear.
That of course means anything and nothing.

According to this calculator (and depending on gamma energy) 2 cm gives a reduction by a factor of 10 (very roughly). It might be as little as a factor of 3 or as much as a factor of 30 (very roughly).

http://www.radprocalculator.com/Gamma.aspx

So if 2 cm of lead is shielding the reaction there wasn't much activity to begin with.

Or else it is a prop.

[Giorgio]

According to this calculator (and depending on gamma energy) 2 cm gives a reduction by a factor of 10 (very roughly). It might be as little as a factor of 3 or as much as a factor of 30 (very roughly).

http://www.radprocalculator.com/Gamma.aspx

So if 2 cm of lead is shielding the reaction there wasn't much activity to begin with.

Or else it is a prop.

This issue was raised in the last TV interview.
Prof. Levi stated that 2 cm lead could have a reducing factor of 3 to 60 according the gamma spectra, and that if the reactions was nuclear in nature the thickness was not suitable.
Prof. Focardi replied that the gamma emission is low, very low, and the 2 cm suffice to avoid any external emission.
He refused to enter into further details.

[MSimon]

Wonderful. Latch onto an aside and don't answer my basic question.

I answered it upthread. I said I thought adding a neutron to an unstable element before it decays (assuming energy available from E=mc^2 is in the MeV range) is improbable.

For that to happen 100% of the time is highly improbable.