Nucleosynthesis – Spallation
Channel: Dominik Hezel
Date: 02/09/2019

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The three lightweights Be, Li and B can neither be produced in a star by fusion, nor subsequently during the r-, s-, or p-process. Only tiny traces of Li were produced during the big bang nucleosynthesis. The three elements Be, Li and B form in spallation reactions in the interstellar medium. This process is sometimes also called l-process for light elements. Spallation means, e.g., a proton hits a nucleus and destroys it, thereby a new element is produced. Two examples of spallation reactions are: (i) one proton hits a 12C nucleus, the proton remains in the nucleus, but two others are ejected. This produces 11B, or in short: 12C(p,2p)11B. (ii) again, one proton hits a 12C nucleus, the proton remains in the nucleus, but four protons and two neutrons are ejected. This produces 7Li, or in short: 12C(p,4p2n)7Li.