Heavy ions

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Heavy Ions is a term used in the fields of radiation chemistry, nuclear physics, and space exploration to describe subatomic particles that are moving through space outside of an atom with a mass and charge greater than electrons (e) and protons (p)).[1]

A heavy ion represents any ion that can be made from any element on the Periodic table by stripping away its electrons and hurling it through space at a given velocity. The reason why scientist classify atomic level ions as heavy ion is to help make a distinction from, smaller subatomic ion particles with velocity, such as electrons, Muon, pion, Positron, etc.

Commonly referenced Heavy Ions in reseach literature includes:

Note: energetic electrons (e) and helium ions (He+) with velocity are traditionally referred to as beta particles and alpha particles, respectively.


Classification by energy Level

Heavy Ions have different penetration depths depending on the kinetic energy level of the Ion source. More specifically, The amount of kinetic energy a Heavy Ion carries is a function of its mass and velocity (see kinetic energy). This is in contrast to high energy photons such as x-ray or gamma rays that have a fixed energy level per particle. This ability to vary the velocity of the Heavy Ion source allow their maximum stopping depth in a target material to be probabilistically predetermined.

low energy

Low energy alpha particles (<= 5 MeV/nucleon) generated by radioactive alpha decay are able to be stopped by a few centimeters of air, or by the skin.

high energy

50 to 5000 MeV/nucleon = 90% of heavy ion flux from the sun.

high energy alpha particles and other HZE ions (> million MeV) which comprise 10% of cosmic radiation are highly penetrating and are able to traverse the human body and also many meters of dense solid shielding, depending on their energy. Although HZE ions make up a small proportion of cosmic rays, their high charge and high energies cause them to contribute significantly to the overall biological impact of cosmic rays, making them as significant as protons in regard to biological impact. The most dangerous GCRs are heavy ionized nuclei such as Fe +26, an iron nucleus with a charge of +26. Such heavy particles are "much more energetic (millions of MeV) than typical protons accelerated by solar flares (tens to hundreds of MeV)." HZE ions can therefore penetrate through thick layers of shielding and body tissue, "breaking the strands of DNA molecules, damaging genes and killing cells."

10^20 eV = maximum energy possible for HZE ions.

In Space exploration

Heavy Ions are referred to as galactic ionss when the source of the Ion is the result of an exploding stars in other galaxies outside our own solar system.

In Integrated Circuit Manufacture

Beams of heavy-ion are widely used in the electronics industry for the purpose of alloying the surface of semiconductor materials through implantation. Use of heavy ion beams has allowed basically any atom possible to be introduces onto the substratrait material, typical sicilon. [2]

In High Energy Physics

The study of heavy ions has is an important subfield of nuclear physics.


Reference

  1. ↑ Recent Trends in Radiation Chemistry, James F. Wishart, B. S. Madhava Rao
  2. ↑ Nuclear Methods in Science and Technology, Yuri M. Tsipenyuk, CRC Press, Jan 1, 1997, page 430

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