Richard,
I strongly suspect that most “galactic cosmic rays” and all of our elements actually came from the Sun’s pulsar core, not from remote regions of the galaxy.
That would explain experimental evidence that:
i.) Minerals in iron meteorites were irradiated prior to compaction, and
ii.) The cosmic-ray exposure ages of iron meteorites are generally much greater than those of stone meteorites that formed further away from the pulsar [1]
1. “Composition of the noble gases in Canyon Diablo,” Geochemical Journal 16, 157-178 (1982) http://www.journalarchive.jst.go.jp/english//jnlabstract_en.php?cdjournal=geochemj1966&cdvol=16&noissue=4&startpage=157