Ir 193 to Au 197

ssills541

Is it possible to bombard Ir 193 with alpha particles to create Au 197? If it isn't why not? And if it is why has no one done it yet?

arivero

use http://atom.kaeri.re.kr/ to sum the masses and tell us. Really, tell us!

I think there is a possible pathway from Hg 201.

mfb

@arivero: That link looks broken.

@ssills541: If you hit it with the right energy to reach a nuclear excitation... why not. Looks like very expensive alchemy, however. Iridium is about as expensive as gold (maybe even more), isotope separation costs, and the energy to accelerate alpha particles is not cheap as well.

arivero

It works for me, the link. Click in the image to go to the relevant mass range
http://atom.kaeri.re.kr/ton/nuc10.html and then click in the nucleus you want info about.

I think that the point is about exothermic or endothermic, not the monetary cost. Of course, the relative abundance of nuclei goes down with the mass, so similar mass have similar abundance at first order. The geology goes after, of course... in this sense, Hg seems cheaper than Iridium

mfb

Now it works for me, too. Probably just a temporary issue.

In both cases, you need a significant energy for the alpha particle to get a reasonable fusion rate. And even in that case, the nucleus might emit one or two neutrons, and you don't get the correct isotope. Therefore, a nuclear resonance of 197Au would be an interesting target.

The individual isotopes have a strong influence on that as well. In general, neutron-rich nuclei are more frequent for heavy elements, as they have an easier way to get produced in supernovae. Mercury and platinum are good examples, where the stable isotopes with the lowest neutron numbers are quite rare.

QuantumPion

You can bombard Hg-196 with neutrons, producing Hg-197 which then decays to Au-197. However, elemental mercury is uncommon to begin with and the natural abundance of Hg-196 is only 0.15%.

arivero

I was thinking simple excitation of Hg201, which has a good abundance, and should go alpha to Pt 197. Then, Pt 197 undergoes spontaneously beta to Au-197.

From the tables, it seems that the energy release in the alpha decay of Hg-201 could be enough to help to keep the reaction going, a sort of subcritical transmutation machine.

QuantumPion

My knowledge of the subject of photoalpha reactions is limited, where can you find photonuclear cross sections for Hg?

arivero

Mine too... Lets hope some other will read the thread in the future :-)