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Particle radiation
 
 
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Particle radiation is the radiation
Radiant energy

Radiant energy is the energy of electromagnetic waves. The quantity of radiant energy may be calculated by Integral radiant flux with respect to time and, like all forms of energy, its SI unit is the joule....
 of energy
Energy

In physics, energy is a scalar physical quantity that describes the amount of Work_ that can be performed by a force. Energy is an attribute of objects and systems that is subject to a conservation law....
 by means of fast-moving subatomic particles. Particle radiation is referred to as a particle beam if the particles are all moving in the same direction, similar to a light beam.

Due to the wave-particle duality, all moving particles also have wave character. Higher energy particles more easily exhibit particle characteristics, while lower energy particles more easily exhibit wave characteristics.

Types and production of particle radiation
Particles can be electrically charged or uncharged:

Particle radiation can be emitted by an unstable atomic nucleus
Atomic nucleus

The nucleus of an atom is the very dense region, consisting of nucleons , at the center of an atom. Although the size of the nucleus varies considerably according to the mass of the atom, the size of the entire atom is comparatively constant....
 (radioactive decay
Radioactive decay

Radioactive decay is the process in which an unstable atomic nucleus loses energy by emitting ionizing particles and radiation. This decay, or loss of energy, results in an atom of one type, called the parent nuclide transforming to an atom of a different type, called the daughter nuclide....
) in the form of a positively charged
Charged particle

In physics, a charged particle is a particle with an electric charge. It may be either a subatomic particle or an ion. A collection of charged particles, or even a gas containing a proportion of charged particles, is called a Plasma , which is called the fourth state of matter because its properties are quite different from solids, liq...
 alpha particle
Alpha particle

Alpha particles consist of two protons and two neutrons bound together into a particle identical to a helium atomic nucleus; hence, it can be written as He2+ or 42He2+....
 (a), a positively or negatively charged beta particle
Beta particle

Beta particles are high-energy, high-speed electrons or positrons emitted by certain types of radioactive Atomic nucleus such as potassium-40. The beta particles emitted are a form of ionizing radiation also known as beta rays....
 (ß) (the latter being more common) , a photon
Photon

In physics, the photon is an elementary particle, the quantum of the electromagnetic field and the basic unit of light and all other forms of electromagnetic radiation....
 (called a gamma particle
Gamma ray

Gamma rays are a form of electromagnetic radiation produced by atom particle interactions, such as electron-positron annihilation or radioactive decay....
, ?), or a neutron
Neutron

The neutron is a subatomic particle with no net electric charge and a mass slightly larger than that of a proton.Neutrons are usually found in atomic nucleus....
.






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Encyclopedia


Particle radiation is the radiation
Radiant energy

Radiant energy is the energy of electromagnetic waves. The quantity of radiant energy may be calculated by Integral radiant flux with respect to time and, like all forms of energy, its SI unit is the joule....
 of energy
Energy

In physics, energy is a scalar physical quantity that describes the amount of Work_ that can be performed by a force. Energy is an attribute of objects and systems that is subject to a conservation law....
 by means of fast-moving subatomic particles. Particle radiation is referred to as a particle beam if the particles are all moving in the same direction, similar to a light beam.

Due to the wave-particle duality, all moving particles also have wave character. Higher energy particles more easily exhibit particle characteristics, while lower energy particles more easily exhibit wave characteristics.

Types and production of particle radiation


Particles can be electrically charged or uncharged:

Particle radiation can be emitted by an unstable atomic nucleus
Atomic nucleus

The nucleus of an atom is the very dense region, consisting of nucleons , at the center of an atom. Although the size of the nucleus varies considerably according to the mass of the atom, the size of the entire atom is comparatively constant....
 (radioactive decay
Radioactive decay

Radioactive decay is the process in which an unstable atomic nucleus loses energy by emitting ionizing particles and radiation. This decay, or loss of energy, results in an atom of one type, called the parent nuclide transforming to an atom of a different type, called the daughter nuclide....
) in the form of a positively charged
Charged particle

In physics, a charged particle is a particle with an electric charge. It may be either a subatomic particle or an ion. A collection of charged particles, or even a gas containing a proportion of charged particles, is called a Plasma , which is called the fourth state of matter because its properties are quite different from solids, liq...
 alpha particle
Alpha particle

Alpha particles consist of two protons and two neutrons bound together into a particle identical to a helium atomic nucleus; hence, it can be written as He2+ or 42He2+....
 (a), a positively or negatively charged beta particle
Beta particle

Beta particles are high-energy, high-speed electrons or positrons emitted by certain types of radioactive Atomic nucleus such as potassium-40. The beta particles emitted are a form of ionizing radiation also known as beta rays....
 (ß) (the latter being more common) , a photon
Photon

In physics, the photon is an elementary particle, the quantum of the electromagnetic field and the basic unit of light and all other forms of electromagnetic radiation....
 (called a gamma particle
Gamma ray

Gamma rays are a form of electromagnetic radiation produced by atom particle interactions, such as electron-positron annihilation or radioactive decay....
, ?), or a neutron
Neutron

The neutron is a subatomic particle with no net electric charge and a mass slightly larger than that of a proton.Neutrons are usually found in atomic nucleus....
. Neutrino
Neutrino

Neutrinos are elementary particles that travel close to the speed of light, lack an electric charge, are able to pass through ordinary matter almost undisturbed and are thus extremely difficult to detect....
s are produced in beta decay
Beta decay

In nuclear physics, beta decay is a type of radioactive decay in which a beta particle is emitted. In the case of electron emission, it is referred to as beta minus , while in the case of a positron emission as beta plus ....
 in addition to beta particles; they interact with matter only very weakly. Photons, neutrons and neutrinos are uncharged particles. The decay events of proton emission
Proton emission

Proton emission is a type of radioactive decay in which a proton is ejected from a atomic nucleus. Proton emission can occur from high-lying excited states in a nucleus following a beta decay, in which case the process is known as beta-delayed proton emission, or can occur from the ground state of very proton-rich nuclei, in which case the...
 and cluster decay
Cluster decay

Cluster decay is a type of nuclear decay in which a radioactive atom emits a cluster of neutrons and protons heavier than an alpha particle. This type of decay happens only in nuclides which decay predominatly by alpha decay, and occurs only a small percentage of the time in all cases....
 also emit (groups of) nucleon
Nucleon

In physics, a nucleon is a collective name for two baryons: the neutron and the proton. They are constituents of the atomic nucleus and until the 1960s were thought to be elementary particles....
s as charged particles, but are comparatively rare.

Other forms of particle radiation, including meson
Meson

In particle physics, mesons are subatomic particles composed of one quark and one antiquark. They are part of the hadron particle family ? particles made of quarks....
s and muon
Muon

The muon is an elementary particle similar to the electron, with negative electric charge and a spin of . Together with the electron, the tau lepton, and the three neutrinos, it is classified as a lepton....
s, occur naturally when (cosmic rays) impact the atmosphere. Mesons are found at high altitudes, but muons can be measured even at sea level.

Charged particles (electron
Electron

The electron is a subatomic particle that carries a negative electric charge. It has elementary particle and is believed to be a point particle....
s, mesons, proton
Proton

The proton is a subatomic particle with an electric charge of +1 elementary charge. It is found in the nucleus of each atom but is also stable by itself and has a second identity as the hydrogen ion, H+....
s, alpha particles, heavier atom
Atom

|-! bgcolor=gray | Properties|-||}The atom is a basic unit of matter consisting of a dense, central atomic nucleus surrounded by a electron cloud of electric charge electrons....
ic ion
Ion

An ion is an atom or molecule which has lost or gained one or more electrons, giving it a positive or negative electrical charge. According to the Bohr_model this will be from or in the outer shield 'n'....
s, etc.) can be produced by particle accelerator
Particle accelerator

A particle accelerator is a device that uses electric fields to propel electric charge Elementary particles to high speeds and to contain them....
s. Ion irradiation is widely used in the semiconductor
Semiconductor

A semiconductor is a material that has electrical conductivity between those of a Electrical conductor and an electrical insulation; it can vary over that wide range either permanently or dynamically....
 industry to introduce dopant
Dopant

A dopant, also called doping agent and dope, is an impurity element added to a crystal or semiconductor lattice in low concentrations in order to alter the optical/electrical properties of the semiconductor....
s into materials, a method known as ion implantation
Ion implantation

Ion implantation is a materials engineering process by which ion s of a material can be implanted into another solid, thereby changing the physical properties of the solid....
.

Particle accelerators can also produce neutrino
Neutrino

Neutrinos are elementary particles that travel close to the speed of light, lack an electric charge, are able to pass through ordinary matter almost undisturbed and are thus extremely difficult to detect....
 beams. Neutron beams are mostly produced by nuclear reactor
Nuclear reactor

A nuclear reactor is a device in which nuclear chain reactions are initiated, controlled, and sustained at a steady rate, as opposed to a nuclear bomb, in which the chain reaction occurs in a fraction of a second and is uncontrolled causing an explosion....
s. For the production of electromagnetic radiation
Electromagnetic radiation

Electromagnetic radiation takes the form of wave propagation waves in a vacuum or in matter. EM radiation has an electric field and magnetic field component which oscillate in phase perpendicular to each other and to the direction of energy Wave propagation....
, there are many methods, depending upon the wave length (see electromagnetic spectrum
Electromagnetic spectrum

The electromagnetic spectrum is the range of all possible electromagnetic radiation frequencies. The "electromagnetic spectrum" of an object is the characteristic distribution of electromagnetic radiation from that particular object....
).

Passage through matter


From the standpoint of radiation protection, radiation is often separated into two categories, ionizing
Ionizing radiation

Ionizing radiation consists of subatomic particle radiation or electromagnetic radiation that are energetic enough to detach electrons from atoms or molecules, ionize them....
 and non-ionizing
Non-ionizing radiation

Non-ionizing radiation or non-ionising radiation refers to any type of electromagnetic radiation that does not carry enough energy per quantum to ionize atoms or molecules — that is, to completely remove an electron from an atom or molecule....
, to denote the level of danger posed to humans. Ionization
Ionization

Ionization is the physics process of converting an atom or molecule into an ion by adding or removing charged particles such as electrons or other ions....
 is the process of removing electrons from atoms, leaving two electrically charged particles (an electron and a positively charged ion) behind. The negatively charged electrons and positively charged ions created by ionizing radiation may cause damage in living tissue. Basically, a particle is ionizing if its energy is higher than the ionization energy
Ionization potential

The ionization potential, ionization energy or EI of an atom or molecule is the energy required to remove one mole of electrons from one mole of gaseous atoms or ions....
 of a typical substance, i.e., a few eV
Electronvolt

In physics, the electron volt is a unit of energy. By definition, it is equal to the amount of kinetic energy gained by a single unbound electron when it accelerates through an Electrostatics potential difference of one volt....
.

According to the International Commission on Non-Ionizing Radiation Protection (see: http://www.icnirp.de/), electromagnetic radiations from ultraviolet to infrared, to radiofrequency (including microwave) radiation, static and time-varying electric and magnetic fields, and ultrasound
Ultrasound

Ultrasound is cyclic sound pressure with a frequency greater than the upper limit of human hearing . Although this limit varies from person to person, it is approximately 20 Hertz in healthy, young adults and thus, 20 kHz serves as a useful lower limit in describing ultrasound....
 belong to the non-ionizing radiations.

The charged particles mentioned above all belong to the ionizing radiations. When passing through matter, they ionize
Ionization

Ionization is the physics process of converting an atom or molecule into an ion by adding or removing charged particles such as electrons or other ions....
 and thus lose energy in many small steps. The distance to the point where the charged particle has lost all its energy is called the range
Range (particle radiation)

In passing through matter, charged particles ionization and thus lose energy in many steps, until their energy is zero. The distance to this point is called the range of the particle....
 of the particle. The range depends upon the type of particle, its initial energy, and the material it traverses. Similarly, the energy loss per unit path length, the 'stopping power
Stopping power (particle radiation)

In passing through matter, fast charged particles ionization the atoms or molecules which they encounter. Thus, the fast particles gradually lose energy in many small steps....
', depends on the type and energy of the charged particle and upon the material. The stopping power and hence, the density of ionization, usually increases toward the end of range and reaches a maximum, the Bragg Peak
Bragg Peak

The Bragg curve plots the energy loss of ionizing radiation during its travel through matter. For protons, Alpha particle, neutrons, and other ion rays, there is a pronounced peak in the curve immediately before the particles come to rest....
, shortly before the energy drops to zero...

See also


  • Nuclear engineering
    Nuclear engineering

    Nuclear engineering is the application of the breakdown of atomic nucleus and/or other sub-atomic physics, based on the principles of nuclear physics....
  • Nuclear physics
    Nuclear physics

    Nuclear physics is the field of physics that studies the building blocks and interactions of atomic nuclei.The most commonly known applications of nuclear physics are nuclear power and nuclear weapons, but the research field is also the basis for a far wider range of applications, including in the medical sector , in materials engineering...
  • Particle accelerator
    Particle accelerator

    A particle accelerator is a device that uses electric fields to propel electric charge Elementary particles to high speeds and to contain them....
  • Physics
    Physics

    Physics is the natural science which examines basic concepts such as energy, force, and spacetime and all that derives from these, such as mass, charge, matter and its Motion ....
  • Radiation
    Radiation

    In physics, radiation describes any process in which energy emitted by one body travels through a medium or through space, ultimately to be absorbed by another body....
  • Radiation therapy
    Radiation therapy

    Radiation therapy is the medicine use of ionizing radiation as part of cancer oncology to control malignant cell s . Radiotherapy may be used for curative or Adjuvant chemotherapy cancer treatment....
  • Radioactivity