At 06:03 PM 8/17/2012, Daniel Rocha wrote:
6.2*10^7 neutrons per 5 min means 200 thousand neutrons per second.
If each one carries 1MeV, that means 3*10^-10^-8J. There's about
3*10^7s every year, which means about 1Joule of radiation emitted per year.
According to wikipedia:
" The
<http://en.wikipedia.org/wiki/International_Commission_on_Radiological_Protection>International
Commission on Radiological Protection (ICRP) recommends limiting
artificial irradiation of the public to an average of 1 mSv (0.001
Sv) of effective dose per year, not including medical and
occupational
exposures.<http://en.wikipedia.org/wiki/Millisievert#cite_note-ICRP103-0>[1]"
Where 1 Sv = 1
<http://en.wikipedia.org/wiki/Joule>J/<http://en.wikipedia.org/wiki/Kilogram>kg
=1Gy
If those 62 million mean the total estimated from the source, given
an isotropic distribution, it means 1000x above maximum background levels.
According to this entries:
<http://en.wikipedia.org/wiki/Radiation-induced_cancer>http://en.wikipedia.org/wiki/Radiation-induced_cancer
http://en.wikipedia.org/wiki/Radiation_poisoning
It is hard to figure out the effects, at least for me, of such
exposure for a long time. But, they are surely deadly.
That does not appear to be so.
First of all, an unconfirmed report of a burst or even steady neutron
radiation, doesn't establish much. Such reports have been in error before.
However, given the value reported, and the (very rough) calculation
done by Daniel, implying 1 joule/year, that is 1 joule for the full
emission, not 1 joule absorbed by a body. To get the full emission in
a body, you'd have to swallow the source, and it would have to all be
absorbed, not escaping. Please don't do that.
Neutrons produce interesting effects. 1 MeV neutrons are not
well-absorbed. I don't know the absorption cross-section for 1 MeV
neutrons, but high-energy neutrons are highly penetrating, and until
they interact, they mostly do nothing. You cannot translate directly
from total emitted energy to total absorbed energy.
1 mSv would be 1 J/kg of fully absorbed radiation. I'd think one
would want to limit radiation exposure to *every kilogram in the
body* to this level. A 1 joule per year neutron source would produce
an absorbed dose far under that for a kilogram at a distance. Easily
this might be under 1 mSv per year. But I'd certainly defer to more
accurate calculations.
Most cold fusion experiments, especially PdD ones, do not produce any
substantial neutron radiation, the levels found are close to
background, sometimes elevated above background to be detectable, but
not much beyond that!
I have not read this particular report yet, so this is not a comment
on it, just on the assertion that this level of radiation would be
deadly. Probably not. But don't sleep with your
specially-neutron-producing cold fusion experiment!
