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High-energy neutrons damage and degrade materials over time; bombardment of materials with neutrons creates collision cascades that can produce point defects and dislocations in the material, the creation of which is the primary driver behind microstructural changes occurring over time in materials exposed to radiation.
In addition, very high energy neutrons can cause ionizing radiation by "neutron spallation" or knockout, wherein neutrons cause emission of high-energy protons from atomic nuclei (especially hydrogen nuclei) on impact. The last process imparts most of the neutron's energy to the proton, much like one billiard ball striking another. The charged ...
Because of the high LET, the relative radiation damage (relative biological effect or RBE) of fast neutrons is 4 times that of X-rays, [7] [8] meaning 1 rad of fast neutrons is equal to 4 rads of X-rays. The RBE of neutrons is also energy dependent, so neutron beams produced with different energy spectra at different facilities will have ...
A fast neutron is a free neutron with a kinetic energy level close to 1 M eV (100 T J/kg), hence a speed of 14,000 km/s or higher. They are named fast neutrons to distinguish them from lower-energy thermal neutrons, and high-energy neutrons produced in cosmic showers or accelerators. Fast neutrons are produced by nuclear processes:
Particle physics or high-energy physics is the study of fundamental particles and forces that constitute matter and radiation.The field also studies combinations of elementary particles up to the scale of protons and neutrons, while the study of combination of protons and neutrons is called nuclear physics.
Radiation safety: Neutron radiation is a hazard associated with neutron sources, space travel, accelerators and nuclear reactors. Neutron detectors used for radiation safety must take into account the relative biological effectiveness (i.e., the way damage caused by neutrons varies with energy).
As a consequence of the Pauli exclusion principle, nuclei with an excess of protons or neutrons have a higher average energy per nucleon.Nuclei with a sufficient excess of neutrons have a greater energy than the combination of a free neutron and a nucleus with one less neutron, and therefore can decay by neutron emission.
Likewise, gamma radiation and X-rays were found to be high-energy electromagnetic radiation. The relationship between the types of decays also began to be examined: For example, gamma decay was almost always found to be associated with other types of decay, and occurred at about the same time, or afterwards.