system
Given the following post, respond as if you're commenting on Reddit:
human
Why does it seem like so many artificial elements are made by combining Calcium with some other element?

I've looked at some synthetic element creation processes, and it seems like a large portion of them produce element X by combining Calcium with element number X-minus-20. Why is this? Why can't they combine Argon with element number X-minus-18? Why does Calcium seem to be the king?
gpt
Are you referring to superheavy elements? The standard way to produce most nuclear species is using fusion-evaporation or projectile fragmentation reactions. These both involve shooting a **stable** beam at some target, and producing a whole bunch of different nuclides. Then you can use a fragment separator to get rid of most of the ones you don't want.

Typical nuclei which are used as stable primary beams are, for example, calcium-40, calcium-48, oxygen-16, argon-40, xenon-124, lead-208, etc.

To produce superheavy elements like 117 and 118, you'd want to use sub-barrier fusion reactions to minimize evaporation of protons and neutrons; you want a product which is as heavy as possible. In the case of element 118 (Onganesson), they used a calcium-48 beam on an actinide target (some isotope of californium).

It comes down to a question of what primary beams are available at your facility, and which beam will give you the best yield of the nuclide you're trying to create.