Spallation

Source: Wikipedia, the free encyclopedia.
Spallation as a result of impact can occur with or without penetration of the impacting object. Click on image for animation.
Nuclear physics
Models of the nucleus
Nuclides' classification
  • N − Z
Nuclear stability
Radioactive decay
Nuclear fission
Capturing processes
High-energy processes
Nucleosynthesis and
nuclear astrophysics
High-energy nuclear physics
Scientists

Spallation is a process in which fragments of material (

atomic weight. In industrial processes and bioprocessing the loss of tubing material due to the repeated flexing of the tubing within a peristaltic pump
is termed spallation.

In solid mechanics

Spallation can occur when a tensile stress wave propagates through a material and can be observed in flat plate impact tests. It is caused by an internal

tensile strength of materials. A fragment or multiple fragments will be created on the free end of the plate. This fragment known as "spall" acts as a secondary projectile with velocities that can be as high as one third of the stress wave speed on the material. This type of failure is typically an effect of high explosive squash head (HESH
) charges.

Laser spallation

Laser induced spallation is a recent experimental technique developed to understand the

thin films (1 micrometre in thickness or less). It is also possible to mode convert a longitudinal stress wave into a shear stress
using a pulse shaping prism and achieve shear spallation.

Nuclear spallation

See also: Cosmic ray spallation

Nuclear spallation from the impact of cosmic rays occurs naturally in

isotopes of aluminium, beryllium, chlorine, iodine and neon
, formed by spallation of terrestrial elements under cosmic ray bombardment, have been detected on Earth.

Nuclear spallation is one of the processes by which a

energy efficiency
of the processes involved, net usable energy could be generated while being able to use actinides unsuitable for use in conventional reactors as "fuel".

Production of neutrons at a spallation neutron source

See also:
ISIS neutron source, Spallation Neutron Source, and SINQ
Science with neutrons
Foundations
Neutron scattering
Other applications
Infrastructure
Neutron facilities

Generally the production of neutrons at a spallation source begins with a high-powered proton

moderators filled with liquid hydrogen or liquid methane
to the energies that are needed for the scattering instruments. Whilst protons can be focused since they have charge, chargeless neutrons cannot be, so in this arrangement the instruments are arranged around the moderators.

X-rays
.

See also

Spallation facilities

References

  1. ^ "Spallation Target | Paul Scherrer Institut (PSI)". Psi.ch. Retrieved 2015-12-12.
  2. S2CID 121427439
    .
  3. S2CID 28796927. Archived from the original
    (PDF) on 2019-03-03. Retrieved October 20, 2019.
  4. S2CID 42506679
    .

External links
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