Am 14.09.2011 01:20, schrieb Horace Heffner:
On Sep 13, 2011, at 12:55 PM, Peter Heckert wrote:
Am 13.09.2011 22:47, schrieb Man on Bridges:
Hi,
On 13-9-2011 20:44, Horace Heffner wrote:
<snip calculation of lead shielding>
Hmmm, is there a way to start and stop a gamma radiation source, as
it may be used only to trigger the process?
There is no other way than shielding or increasing the distance.
Rossi could inside use a shield that is moved electrically or by heat
(bimetal).
Or he could control the distance to the gamma source.
If it is a very small point source the /local/ intensity of radiation
could be changed by factor 10^2 or 10^3.
Peter
The above is incorrect. A 2 cm thick lead shield will only reduce
Co-60 gammas by 75%.
I = I0 * exp (-0.694 * x)
So we want I/Io = 0.01 to achieve 1/100 reduction factor.
I/I0 = exp (-0.694 * x)
0.01 = exp (-0.694 * x)
ln(0.01) = -0.694*x
x = ln(0.01)/(-0.694) = 6.63
It takes 6.6 cm of lead to divide Co-60 gamma intensity by 100.
Similarly, it takes about 10 cm of lead (on all sides) to attenuate
CO60 gammas by a factor of 1/1000.
Maybe I am in error.
I understand it this way:
A shield cannot alter the wavelength and so it cannot alter the photon
energy respective frequency.
Only the amount or density of gamma photons can be changed by photon
absorption.
Now, lets assume the gamma radiator has a volume of 1mm. Then the photon
density in 100mm distance must be 40000 times weaker as the density
directly measured in 0.5 mm distance at the surface of the gamma source.
(Inverse square law as in optics)
Even without shield we can get a large attentuation factor purely from
distance, if the diameter of the source is small.
So if the gamma source is in direct contact with nickel, the photon
density must be 100 times larger than in 10 mm distance.
Is this wrong?
Another thought:
I think Rossi is naive and will loose if he think he can commercialize a
discovery of this magnitude and eternal history changing importance and
keep it secret. This is impossible to do, he must go the scientific
route, not the commercial route.
Also his fans and investors are naive to believe this.
As soon as it is totally and unmistakenly clear, this is a nuclear
reaction that produces large amounts of energy, law will stop him. And
international scientific research will start.
You cannot discover the stone of philosophers and commercialize this and
keep it secret, this is impossible.
This must be done in a scientific way.
As soon as large amounts of energy are produced, it must be also
scientifically investigated, if this can be abused to build bombs and so
on. Rossi says no, this is not possible, but as long as it is a secret
he cannot proof it is without dangers.
I think no government can tolerate something like this going on and
reaching very large dimensions unsupervised.
The unknown potential of danger is too high.
Only if his customer is NASA or another large scientific and trusted
organisation he could have luck selling this.
Best,
Peter
