ItchyFungus said:
I see, the gold is just an example for creating other elements we are currently lacking. Just basically playing with imagination haha. I appreciate all of your inputs, I am aware that there is profit on limited resources and government funding and so on, but perhaps you guys can come together in a secret lab and just make it happen haha.
All jokes aside, I appreciate the information.
It's not expensive because we don't know how to do it, or because we're greedy, it's expensive because of good physical rules.
Let's use gold as an example, and do an estimation of the cost of making gold. One way to make gold in nuclear reactions would be by pulling a proton from 198Hg. First problem: 198Hg makes up 10 % of natural mercury. Mercury is US$17.4 per kg, call it $20, so you've got to buy $200 worth of Hg to get 1Kg of 198Hg. Let's assume you're not willing to use isotopic mercury, because that'll be several orders of magnitude more expensive than gold (likely tens of thousands of dollars a gram), so we'll have to worry about the other isotopes later. But that's pretty cheap compared to gold, so far so good.
Let's use a triton beam. Why? The ejectile nucleus will be 4He, which is very well bound, so the reaction will be exothermic.
So the reaction would be 198Hg(t,a)197Au.
But then, tritium isn't exactly easy to get. According to wiki, tritium is $30000 a gram, and 400 grams is made a year.
Oh dear. Gold is $40.71/gram at the moment. So we're done here.
It's probable that there's another reaction that would work, let's say 198Hg(12C,13C)197Au. Negative Q-value but not too negative. That'll do. Let's assume the carbon is close enough to free.
Ok, then you've got to make a target of mercury. Since mercury is liquid, this isn't easy, let's use HgS (paper here
http://www.sciencedirect.com/science/article/pii/0029554X77906309). So, let's make a super super thick target of HgS (say, 1 square cm, mass 100 mg of Hg, ~10^20 atoms/cm^2) and blast a high intensity beam of 12C on it. Say, 100 particle microamps (10^15 particles/second), 200 MeV 12C. I don't know what the reaction cross section of this reaction is, but let's be optimistic and say that it's 100 mb. That gives us about 10^10 particles of gold produced a second. Ah, but then we have natural hg, so that's a billion atoms of gold produced a second. Which sounds like a lot, but that's only 10^-16 grams of gold produced per second! You'd have to run your accelerator for 3000 years just to convert all the 198Hg in your 100mg natural mercury target into gold, under these conditions!
And then you'd still have to chemically purify it to remove all the other junk you made!
This is of course, an estimate, and I might be out by a factor of 100 either way. But you can see even then, it's just not worth it.