NetNews Usenet Archive 1992 #16/NN_1992_16.iso/spool/sci/physics/fusion/1855

Text File | 1992-07-27 | 4.0 KB | 76 lines

Newsgroups: sci.physics.fusion
Path: sparky!uunet!darwin.sura.net!mips!pacbell.com!tandem!zorch!fusion
From: <[e-mail]>
Subject:  The Ying Thing & Rehash of Menlove and Jones
Message-ID: <[e-mail]>
Sender: [e-mail] (Scott Hazen Mueller)
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Organization: Sci.physics.fusion/Mail Gateway
Date: Tue, 28 Jul 1992 03:35:40 GMT
Lines: 64

For those concerned about injecting extraneous bozons into their magic
soup perculating under a plexiglass pyramid (purchased from Edmund
Scientific so it has to be good) I thought I'd inject some real numbers.
The ranges for 5 MeV alpha particles in H2O, Al, and Iron are respectively
0.004 cm, 20 micrometers, and 10 micrometers.  It's tough to get those
little buggers into your sample.  As to putting the source right on the
Pd, in olden times we used to make alpha sources by disolving Po in
dilute HCl.  Then when you dipped a nickel wire into the soln, the Po
would plate out onto the wire.  I suppose something like that would
work for Pd, but don't try this at home, kids!

Next, the attenuation of gamma rays.  The mass absorption coefficients
for 1.5 MeV gammas are roughly 0.05 cm^2 per gm.  To convert that
to a linear coefficient, multiply by the density.  At lower energies
the attenuation is strongly energy dependent and Z dependent.  So you
can get gammas into the sample, and right on through it with no interaction.
But, for the life of me, I can't see what 1.5 MeV (or less) gammas have
to do with fusion.  Can anyone explain how these puny photons are
going to do what 23 MeV photons probably don't do either?

Tom Droege wants to no that we skeptics are still here.  My comment
at this point is basically to repeat someone else's suggestion that
you change the period of your source on/source off cycles.  Too many
things run in a daily cycle so 12 or 24 hr cycles are suspect.
Michelson, when measuring c in California, found that his results
should a daily cycle because the length of the path varied due to
earth tides.  To mention a couple of possibles: line voltage and
air temperature.

Jim Carr has been saying nice things about the results of the Menlove
and Jones experiment that need some correcting.  Firstly the notion
of bursts of neutrons was overstated.  If you look at the data, it
is clear that most of the net effect was events involving 2 to 4
counters firing, as I recall.  Single-counter events were excluded
from the data sample.  Jim, you are correct in saying that this
reduces the possibility that "accidental coincidences" account for
the result, but that is "good" only if the source reaction is in
fact one that produces single neutron events.  Consider instead
the situation where you are detecting muon induced spallation, a
multi-neutron process.  Basically the enforced coincidence
requirement then makes the detector much more sensative to the
muon induced background than it would be to cold fusion which, at
low rates would NOT produce many multineutron events.  In short
they threw the baby out with the bath.

While Tom Droege continues to take pot shots at Takahashi's
calorimetry, I'll chime in to say that the neutron data is pretty
suspect as well.  I have already pointed out that most of what
is being called "neutrons" is probably are gamma ray pulses.  The
next point I raise has to do with the correlation between count rate
in the detector and the phase of the electrolysis current (high versus
low current).  If you examine the recorded pulse height spectrum
shown by Dr. T in his MIT presentation, you will see that the rate
rises steeply as you move to lower pulse heights until you reach the
electronic threshold which gives a sharp cutoff on the low end.  Most
of the recorded counts come from pulses near threshold so very
small changes in that threshold can have a big effect on the total
number of counts recorded.  So I suggest that perhaps the threshold
moves when the electrolysis current is changed.  Isn't neat howmany
ways you can generate data in support of what ever notion catches
your fancy?

Dick Blue, writing in haste
NSCL @ MSU