Related Experiment Video
Updated: Aug 11, 2026
04:36
Production of Synthetic Nuclear Melt Glass
Published on: January 4, 2016
Spallation processes and nuclear interaction products of cosmic rays
1E.O. Hulburt Center, Naval Research Laboratory, Washington, DC 20375-5000.
Physics Reports
|August 1, 1990
Summary
Cosmic-ray nuclei undergo nuclear collisions in space, altering their composition. Studying these changes helps us understand cosmic-ray origins, interstellar medium properties, and galactic processes.
Area of Science:
- Astrophysics
- Nuclear Physics
- Cosmic Ray Physics
Background:
- Cosmic-ray nuclei heavier than helium interact with interstellar gas, changing their composition.
- Understanding the original composition of cosmic rays requires inferring it from observations near Earth.
Purpose of the Study:
- To infer the elemental and isotopic composition of cosmic rays at their sources.
- To test theories regarding cosmic-ray origin, stellar nucleosynthesis, and interstellar medium evolution.
- To utilize nuclear spallation and radioactive decay to study cosmic-ray acceleration, propagation, and galactic confinement.
Main Methods:
- Analysis of the observed isotopic and elemental composition of cosmic rays near Earth.
- Modeling nuclear spallation processes and the production/decay of radioactive nuclides.
- Investigating long-lived spallation products to probe interstellar medium density and structure.
Main Results:
- Observed cosmic-ray composition is a result of nuclear collisions in the interstellar medium.
- Nuclear spallation products provide insights into cosmic-ray acceleration and propagation.
- Long-lived spallation products can reveal details about the interstellar medium's nature.
Conclusions:
- The composition of cosmic rays near Earth reflects both source properties and interstellar interactions.
- Nuclear physics, particularly spallation, is crucial for understanding cosmic-ray phenomena.
- Further study of spallation products can enhance our knowledge of the interstellar medium and cosmic-ray lifecycle.
Keywords:
NASA Discipline Number 04-10NASA Discipline Radiation HealthNASA Program Radiation HealthNon-NASA CenterMore Related Videos
Related Concept Videos
02:21Spontaneity
A spontaneous process is one that occurs naturally under certain conditions. A nonspontaneous process, on the other hand, will not take place unless it is “driven” by the continual input of energy from an external source. Processes have a natural tendency to occur in one direction under a given set of conditions. Water will naturally flow downhill (spontaneous process), but uphill flow (nonspontaneous process) requires outside intervention such as the use of a pump. Iron exposed to the earth’s...
03:18Radioactivity and Nuclear Equations
Nuclear chemistry is the study of reactions that involve changes in nuclear structure. The nucleus of an atom is composed of protons and, except for hydrogen, neutrons. The number of protons in the nucleus is called the atomic number (Z) of the element, and the sum of the number of protons and the number of neutrons is the mass number (A). Atoms with the same atomic number but different mass numbers are isotopes of the same element.
A nuclide of an element has a specific number of protons and...
A nuclide of an element has a specific number of protons and...
03:23Types of Radioactivity
The most common types of radioactivity are α decay, β decay, γ decay, neutron emission, and electron capture.
Alpha (α) decay is the emission of an α particle from the nucleus. For example, polonium-210 undergoes α decay:
Alpha (α) decay is the emission of an α particle from the nucleus. For example, polonium-210 undergoes α decay:
02:50Nuclear Fission
Many heavier elements with smaller binding energies per nucleon can decompose into more stable elements that have intermediate mass numbers and larger binding energies per nucleon—that is, mass numbers and binding energies per nucleon that are closer to the “peak” of the binding energy graph near 56. Sometimes neutrons are also produced. This decomposition of a large nucleus into smaller pieces is called fission. The breaking is rather random with the formation of a large number of different...
02:45Nuclear Fusion
The process of converting very light nuclei into heavier nuclei is also accompanied by the conversion of mass into large amounts of energy, a process called fusion. The principal source of energy in the sun is a net fusion reaction in which four hydrogen nuclei fuse and ultimately produce one helium nucleus and two positrons.
A helium nucleus has a mass that is 0.7% less than that of four hydrogen nuclei; this lost mass is converted into energy during the fusion. This reaction produces about...
A helium nucleus has a mass that is 0.7% less than that of four hydrogen nuclei; this lost mass is converted into energy during the fusion. This reaction produces about...
03:20Nuclear Transmutation
Nuclear transmutation is the conversion of one nuclide into another. It can occur by the radioactive decay of a nucleus, or the reaction of a nucleus with another particle. The first manmade nucleus was produced in Ernest Rutherford’s laboratory in 1919 by a transmutation reaction, the bombardment of one type of nuclei with other nuclei or with neutrons. Rutherford bombarded nitrogen-14 atoms with high-speed α particles from a natural radioactive isotope of radium and observed protons being...