From: Frank Close <FEC@v2.rl.ac.uk>
Subject:  helium noise
Reply-To: Frank Close <FEC@v2.rl.ac.uk>
Organization: Sci.physics.fusion/Mail Gateway
Date: Tue, 22 Dec 1992 15:21:37 GMT

Mitchell Swartz has questioned some of my remarks about helium and Jim Carr
has partly come to my rescue. Thanks to you both.

First MS is right about the S/N with argon;I meant to write neon(about 3 times
more abundant than 4He in air). One inert element is much like another to
an inert physicist:-)

Now to numbers; the 100W for 10minutes produces some 10**16 not 10**14 helium
atoms when you put in the proper numbers for the energy release per reaction.
So this should be measurable above background unless one is rather careless.
(It may amuse readers to look at Huizenga's account of the original Pons and
Hawkins claims to have found helium, as reported by Simons and Walling in
April/May 89. The actual amounts *exceeded* by far the numbers expected for
fusion! The reason was that helium in the air - not even traces absorbed in
the rods -  was being measured.)

Jim Carr commented on this problem for open cells. Jim implicitly higlights
here a recurring problem that plagues this field: if you want to measure subtle
effects, take care to eliminate sources of error. Someone recently commented
on systematic errors; it is the awareness of these that is part of the standard
particle/nuclear physics experimentalist training but seems to be poorly
understood by some on this net who advertise multi-sigma heat uncritically.

10**5 is "easy" (relatively speaking as Jim notes) *if* you have eliminated
background. If you havent, then you may easily "detect" 10**14 (say)
from the air. Mitchell has done an interesting service here; he has
advertised *numbers*, which too often are missing from this supposedly
scientific discussion net, and shown how dangerous helium measurements
can be if not done carefully. Look at the claims to have found helium
in the literature. Recall Bush et al; their *best* measurement saw helium
at about 1 part in 100 of that needed to explain their claimed heat.
This magnitude is quite consistent with the sort of numbers that Mitchell
is warning about from air.

In measurements of helium in the FP rods, conducted by various labs in
a double blind test (see Huizenga), limits of less than 10**14 were
clearly established. So the bottom line is that properly controlled
expts can limit 4He at levels far below that required by FP claims that
dd fusion is producing helium.

Also note that I am urging measurement of helium *in the rods* not
simply the gas phase.

The 10**5 number I wouldnt defend particularly except in the case of 3He
(whose presence in air is nugatory, though the source of even this
trifling amount is tantalising - see my book's account of Steve Jones group's
interest in terrestrial fusion that was motivated in part by this).
Limits of 3He at this level were established in some expts reported to
the ERAB panel in 1989. Note that tritium beta decays into 3He and so
measurements of 3He also imply stringent limits on tritium. Jed Rothwell
keeps insisting that tritium has been measured but *what* is actually
measured? Not trititum; one *infers* tritium from a chain of arguments
that may or may not be right. An example from 1989; FPH claimed to find
tritium from an electron spectrum of supposed beta decays. (Actually it
wasnt FPH who did the measurements but some unacknowledged colleagues
from the UU campus). But what was there to show whether these electrons
were from tritium decay as against e.g. radioactive potassium (of which there
is plenty around?). The care needed in some tritium expts was widely advertised
at the APS meeting in Baltimore, May 1989; not everyone seems to have been
listening.

Chuck Sites is making isotope and other measurements on some of Tom's used
rods. Has Tom produced some heat or are these control measurements?
In particular, it will be interesting if you can measure the ratio of
Pd isotopes in these "non-nuked" samples. One of the orignial claims that
some heat producing rods had anomalous Pd isotopes arose because of
misidentification of ZrO (my notes are not handy;maybe someone can remember
details). So, what is the ratio of masses in the 104 to 108 range?
A deviation from the expected Pd in the control samples may be due to
compounds. A deviation *after* a heat production may be due to anomalous
isotopic abundances, and evidence of a nuclear process, or it may be
compounds!) First establish whether you can resolve these slight differences
in mass.



Newsgroups: sci.physics.fusion