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Science Forum Index » Physics - Particle Forum » resonance states of the neutron
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| Guest |
 Posted: Mon Apr 28, 2008 7:22 am |
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Hi,
The neutron is believed to have some sort of internal structure. I'm
not up on current quark theory. The free neutron decays with a half
life of ~15 min according to:
n -> p + e + 1.29 MeV, (ignore neutrinos)
That's a lot of energy per unit mass. Fortunately the relatively long
decay time provides some kind of "get away from danger grace time".
However, in the event of a relatively high energy inelastic nuclear
collision, internal resonance states of the neutron might be excited
that might enhance the rate of decay. That would make high kinetic
energy neutrons more dangerous than might be expected from the value
of the kinetic energy alone. I'm thinking of processes that might take
place in less than a millisecond.
My questionis to any quark experts out there: Are internal resonance
states of the neutron known that might effectively 'catalyze' more
rapid release of neutron energy? |
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| Uncle Al |
| Posted: Mon Apr 28, 2008 3:11 pm |
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Guest
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d.086@hotmail.com wrote:
Quote:
Hi,
The neutron is believed to have some sort of internal structure. I'm
not up on current quark theory. The free neutron decays with a half
life of ~15 min according to:
n -> p + e + 1.29 MeV, (ignore neutrinos)
That's a lot of energy per unit mass. Fortunately the relatively long
decay time provides some kind of "get away from danger grace time".
What does that mean? Look up the mean velocity of a thermal neutron.
Can you run supersonic? Compare rads with rems for beta-rays and fast
neutrons.
Quote: However, in the event of a relatively high energy inelastic nuclear
collision, internal resonance states of the neutron might be excited
that might enhance the rate of decay. That would make high kinetic
energy neutrons more dangerous than might be expected from the value
of the kinetic energy alone. I'm thinking of processes that might take
place in less than a millisecond.
High energy neutrons decay with *longer* externally observed
half-lives - Special Relativity.
Quote: My questionis to any quark experts out there: Are internal resonance
states of the neutron known that might effectively 'catalyze' more
rapid release of neutron energy?
H-bomb secondaries propagate without any exotic corrections for fast
(2.45 MeV for D+D, 14.1 Mev for D+T) neutron decay.
--
Uncle Al
http://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)
http://www.mazepath.com/uncleal/lajos.htm#a2 |
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| Guest |
| Posted: Tue Apr 29, 2008 1:06 pm |
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On Apr 28, 6:11 pm, Uncle Al <Uncle...@hate.spam.net> wrote:
Quote: What does that mean?
Metaphorical language.
Quote:
High energy neutrons decay with *longer* externally observed
half-lives - Special Relativity.
My questionis to any quark experts out there: Are internal resonance
states of the neutron known that might effectively 'catalyze' more
rapid release of neutron energy?
H-bomb secondaries propagate without any exotic corrections for fast
(2.45 MeV for D+D, 14.1 Mev for D+T) neutron decay.
We know all that. But you haven't answered the question
Let's use the device of metaphor to illuminate the question better.
Let's say you have a chemical substance that is unstable and decays
with a half life of 15 minutes at a specific temperature. At that
temperature, energy is distributed among internal degrees of freedom
and Boltzman statistics and kinetic factors controls the rate at which
molecules surmount the energy barrier and decay to product(s). When
you raise the temperature, there is a greater amount of energy
distributed amoung the internal degrees of freedom and molecules
surmount the kinetic energy barrier at a faster rate.
Now the neutron is said to have internal structure and weak force
mediated beta decay. I don't know all the details. My question is
whether it is known whether internal degrees of freedom can be excited
within the neutron by inelastic collision and increase the rate of
beta decay. This is unrelated to relativistic effects. Is there a
known quantum mechanical energy level diagram for the neutron? If so
then Boltzman statistics and kinetic theory would allow prediction of
enhanced decay rate. The nucleus is held together by the strong force
and it does have higher energy states. These higher energy states can
be accessed by inelastic collision with neutrons or charged particles,
by neutron absorbtion, by high energy EM excitation all to enhance the
rate of nuclear reactions, typically fission energy release.
Do I make myself clear? The neutron is said to have internal
structure. If so then there ought to be some expectations about its
behavior. BTW this may be controversial but there are plenty of
nuclear rate processes whose rate changes at temperatures near
ambient. There are isotopes whose rate of beta decay or electron
capture decay depend on crystal field (chemical) effects. To put my
question in the most simple terms, is the rate of neutron beta decay
temperature dependent? |
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| Uncle Al |
| Posted: Thu May 01, 2008 4:39 pm |
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Guest
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d.086@hotmail.com wrote:
Quote:
On Apr 28, 6:11 pm, Uncle Al <Uncle...@hate.spam.net> wrote:
What does that mean?
Metaphorical language.
High energy neutrons decay with *longer* externally observed
half-lives - Special Relativity.
My questionis to any quark experts out there: Are internal resonance
states of the neutron known that might effectively 'catalyze' more
rapid release of neutron energy?
H-bomb secondaries propagate without any exotic corrections for fast
(2.45 MeV for D+D, 14.1 Mev for D+T) neutron decay.
We know all that. But you haven't answered the question
Let's use the device of metaphor to illuminate the question better.
Let's say you have a chemical substance that is unstable and decays
with a half life of 15 minutes at a specific temperature. At that
temperature, energy is distributed among internal degrees of freedom
and Boltzman statistics and kinetic factors controls the rate at which
molecules surmount the energy barrier and decay to product(s). When
you raise the temperature, there is a greater amount of energy
distributed amoung the internal degrees of freedom and molecules
surmount the kinetic energy barrier at a faster rate.
Now the neutron is said to have internal structure and weak force
mediated beta decay. I don't know all the details. My question is
whether it is known whether internal degrees of freedom can be excited
within the neutron by inelastic collision and increase the rate of
beta decay. This is unrelated to relativistic effects. Is there a
known quantum mechanical energy level diagram for the neutron? If so
then Boltzman statistics and kinetic theory would allow prediction of
enhanced decay rate. The nucleus is held together by the strong force
and it does have higher energy states. These higher energy states can
be accessed by inelastic collision with neutrons or charged particles,
by neutron absorbtion, by high energy EM excitation all to enhance the
rate of nuclear reactions, typically fission energy release.
Do I make myself clear? The neutron is said to have internal
structure. If so then there ought to be some expectations about its
behavior. BTW this may be controversial but there are plenty of
nuclear rate processes whose rate changes at temperatures near
ambient. There are isotopes whose rate of beta decay or electron
capture decay depend on crystal field (chemical) effects. To put my
question in the most simple terms, is the rate of neutron beta decay
temperature dependent?
Given substructure, where is the neutron's electric dipole moment?
Its electric quadrupole moment?
<http://minoserv.maps.susx.ac.uk/~nedm/method1.htm>
|d| < 3.0 10^(-26) e-cm
Why would fractional eV externals affect MeV nuclear chemistry?
(Except for electron capture inverse beta-decay where the kinetics are
not nuclear)
Newton was wrong. Get over it. Quantum mechanics is the proper
model.
--
Uncle Al
http://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)
http://www.mazepath.com/uncleal/lajos.htm#a2 |
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| Guest |
| Posted: Thu May 01, 2008 4:40 pm |
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Quote: H-bomb secondaries propagate without any exotic corrections for fast
(2.45 MeV for D+D, 14.1 Mev for D+T) neutron decay.
H-bomb secondaries undergo disassembly within nanoseconds so any
second order correction for neutron decay rate is insignificant (at
that time scale). |
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| Guest |
| Posted: Thu May 01, 2008 4:40 pm |
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On Apr 29, 4:06 pm, d....@hotmail.com wrote:
Quote: To put my
question in the most simple terms, is the rate of neutron beta decay
temperature dependent?
I don't seem to be making any progress in probing the minds of quark
experts so I'll use the metaphorical device again to rephrase the
question.
The neutron is a spin 1/2 particle and so neutron magnetic resonance
spectroscopy exists and at a field strength of 14.7 Tesla the
resonance frequency of the neutron is around 30 MHz, (IIRC). It is
known that at very low temperatures, the neutron undergoes total
reflection from the walls of many materials. So, it is possible to do
long time neutron magnetic resonance studies, except for the
complication that the neutron decays. I have no knowledge of the
magnetic resonance of unstable nuclei (it is too dangerous) so I
cannot use that for constructing another metaphor. But I do have
knowledge of electron spin resonance. In ESR one selects an electron
spin label that is long lived and one generally studies spin labeled
molecules that are long lived. However, if one's molecule or one's
spin label decays in a time of about 15 minutes then one would expect
that decay to be reflected in ESR line shape or in the time dependent
signal decay. If only one decay mechanism pertains then one would see
only monoexponential decay. If more than one decay mechanism pertains
then one would expect to observe biexponential or multiexponential
signal decay. Now the mathematical analysis of noisy multiexponential
decay is almost intractable so such analysis is almost on the
forefront of mathematics, AFAIK.
However, my rephrased metaphorical question is directed at experts in
neutron magnetic resonance. Has any multiexponential signal decay
analysis of free neutron magnetic resonance been derived? If so that
would shed some light on the question of whether neutron beta decay is
temperature dependent and on the existence of resonance states of the
neutron. That should provide some kind of validation for the quark
experts. I'm an experimentalist. So far I have not seen sufficient
experimental validation to justify me putting sufficient effort into
the mastery of quark theory. |
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| J. J. Lodder |
| Posted: Thu May 01, 2008 4:40 pm |
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Guest
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<d.086@hotmail.com> wrote:
Quote: Do I make myself clear? The neutron is said to have internal
structure. If so then there ought to be some expectations about its
behavior. BTW this may be controversial but there are plenty of
nuclear rate processes whose rate changes at temperatures near
ambient. There are isotopes whose rate of beta decay or electron
capture decay depend on crystal field (chemical) effects.
That is an electron density effect, not a temperature effect.
(except indirectly)
Quote: To put my
question in the most simple terms, is the rate of neutron beta decay
temperature dependent?
To make dent in the neutron decay rate
you need -huge- electron densities.
Think white dwarf/neutron star,
Jan |
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