In the PS210 experiment another process has been chosen. When a antiproton (red) circulating in an accelerator passes a heavy target-nucleus (green), e.g. Xenon, close enough, electron-positron pairs (blue) are produced accidently.
If an electron-positron pair has been created, which as said above is a very rare process, then in even more rare cases it is possible that the antiproton catches the positron.
And then Antihydrogen is produced.
The probability for this is 0.000 000 000 000 000 01 %