At 02:00 PM 12/6/2009, Jones Beene wrote:
The 3 alpha reaction 12C(n,n')3alpha is well known. I don't know
what you are talking about.
I am talking about essentially a zero cross-section of this reaction for
thermal neutrons. Duh! This is why graphite is used as a moderator in
fission reactors where the average fission neutron starts out at about one
MeV.
Very odd, this conversation. The breakup of 12C into three 4He is not
from thermal neutrons, it is from energetic neutrons.
That's why triple tracks of the kind found by SPAWAR are considered
diagnostic for energetic neutrons. There are far more tracks
generated in the SPAWAR experiments, on detector surfaces unreachable
by charged particles, apparently caused by proton knock-on, so a
substantially lower level of triple tracks would be expected. Proton
knock-on tracks would resemble other radiation, but triple tracks are
strong evidence of energetic neutrons, that's why the Triple Track
paper had such an impact.
The supposition of higher energy neutrons in LENR is absolutely ludicrous
after all of these years of non-detectability !!!
This really shows, I'm afraid, ignorance of the situation, of why it
took so long to discover this radiation. The level is quite low, down
in or close to the noise, for detectors at any significant distance
from the source. To detect these neutrons, it was necessary to have a
detector very close, and even then the levels were too low for
reliable detection by electronic detectors, which is how the bulk of
searching for neturons was done. CR-39 doesn't actually detect
neutrons, it is only sensitive to charged particles. However,
energetic neutrons will, in a proper material (and the polycarbonate
itself is such a material), with generate knock-on protons from
hydrogen in the material and a few triple tracks from interactions
with carbon in the material. These tracks only have a limited range
in the material, so the large majority of neutrons aren't detected.
Thermal neutrons aren't detected at all. "Ludicrous"? Actually, if
there are LEN reactions that effect fusion, we would expect secondary
reactions that will generate neutrons. It is highly likely at this
point that the primary reaction does not involve neutron emission at
all; as a possible theory, I point to the Tetrahedral Symmetric
Condensate theory of Takahashi, which predicts deuterium as fuel,
helium as ash, a Q factor of the right value for d-d fusion (but not
through the mechanism of d-d fusion), and very short-range EUV
radiation as the excited Be-8 nucleus formed sheds energy before
fissioning into two alpha particles. The last prediction has not been
observed. And it's difficult to observe, Horace has suggested an approach.
There may be more than one reaction, but the Q factor observed leads
to a conclusion that the *effect* is to convert deuterium into helium.
If this is happening, there will be plenty of energy available to
sometimes cause classic brute-force fusion, and this explains the
neutrons. Heffner has also suggested, quite cogently, that if D-T
fusion is the reaction involved in these secondary reactions, doping
the cell with tritium should increase the neutron production. I doubt
I'll be able to test that myself, but the cells I'm designing should
make it very easy for anyone with access to tritium; these cells,
which will be quite inexpensive as experiments go in this field,
implement a codeposition protocol on a small scale, in a
configuration optimized for the production and measurement of neutron
radiation. (Gold cathode wire, stacks of CR-39 detectors, with the
detection surface being the interface between a pair of CR-39 layers,
and the detector surface being arranged all the way from very close
to the cathode and quite far away, looking for information about the
spatial distribution of the radiation and an inference as to its
original flux based on expectation of inverse square law variation of
detected radiation.)
Geeze, where is any semblance of reality in this claim of carbon fission?
As Horace has indicated, it's a well-known reaction. That should be
obvious; if it were not well-known, triple tracks would not be ascribed to it!
http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6X49-46MV3DB-CG&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&_docanchor=&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=17d04e2c34baf78840a5d01dff09d8c0
This wasn't an invention of the SPAWAR group. By the way, the above
link is to a paper, "Fast-neutron spectrometry using the
triple-reaction in the CR-39 detector," 2002, and if anyone can
provide me with a copy, I'd very much appreciate it. It appears to
contain information about the effect of etching time and neutron
energy on the triple-track production efficiency. Just what the
doctor ordered, it would seem.
http://www.iscmns.org/catania07/Abstracts.pdf
In Figure
2a, an arrow indicates what appears to be a triple pit. Figure 2b
shows an image of this triple pit at
magnification 1000.. Possible explanations for the formation of a
triple track are (i) that it is due to
overlapping single tracks or (ii) it is the result of reactions that
emit three particles of similar mass
and energy. Focusing inside the triple pit to examine the bottom of
the pit, Figure 2c, it appears that
the individual lobes of the triple track are splitting apart. This
favors explanation (ii) as the source
of this triple pit. Such triple pits have been shown to form when
CR-39 is bombarded with energetic
neutrons.5 The main constituent of CR-39 is 12C (32% by weight). A
neutron can briefly form a
metastable 13C then shatter into three alpha particles and the
residuals of the reaction can be viewed
in the CR-39 detector as a three-prong star similar to those shown
in Figure 2b.5 The deuterated
water used in these experiments does contain tritium and there is
prior evidence that tritium
production in these cells does occur6. One possible source of
neutrons energetic enough to shatter
carbon atoms is tritium-deuterium fusion.
Note 5 is:
5. A.M. Abdel-Moneim, A. Abdel-Naby, Radiat. Meas., Vol. 37. p. 15 (2003).
While a certain level of an appearance of triple-tracks could occur
from mere coincidence, the incidence is far above that level, and the
position where these tracks are found (generally on the back side of
the detector, away from the cathode), combined with the short track
length of charged particle radiation (at reasonable energies),
indicates that the source is neutrons in any case. By the use of
stacks of detectors I expect to be able to rule out very-high-energy
charged particles, not that these are expected. (A charged particle
able to penetrate a piece of CR-39 that is 1/16 of an inch thick, I
believe that's the thickness of the chips SPAWAR et al have been
using, is very high energy.)
Then I can look for thermal neutrons using a Boron-10 converter
screen, which will capture some of them and convert them into charged
particle tracks. And then I'll look, deeper in the stack, for
energetic neutron evidence. I should not see, for example,
triple-tracks on the front surface of a detector in contact with the
Boron-10 screen, I expect (unless it is background).
