https://doi.org/10.1351/goldbook.08730
Beam of electrically neutral particles that cause ionization by interacting with atoms in a material, producing electrically-charged particles that subsequently cause direct ionization in the material.
Example:
Gamma-rays and X-rays, which produce electrons, and neutrons, which produce alpha and beta particles.
Gamma-rays and X-rays, which produce electrons, and neutrons, which produce alpha and beta particles.