The glossary story... Home    Author    Research    Methodology    Contact
  Glossary terms... A    B    C    D    E    F    G    H    I    J    K    L    M    N    O    P    Q    R    S    T    U    V    W    XYZ    numbers
  Collections... dose    elements    neutrons    nuclides    radiation    radioactive decay    reactions    reactors radiation safety   
units    U.S.Regs   
  Further Reading... general    nuclear science    nuclear engineering    health physics   

A Collection of Neutron Terms...
beta-delayed neutron
A neutron that has been emitted by an excited state of a nucleus immediately following beta decay. The emission occurs when the decay leaves the daughter nucleus in an excited state that is above the neutron separation energy. Delayed neutrons account for approximately 0.75% of the neutron output from fission and this is an important aspect of controlling the increase in energy output of reactors.

Related to delayed fission neutron.
Related to fission neutron.
Related to prompt fission neutron.


Bragg neutron
(obsolete term)

A cathode ray that supposedly picked up enough positive electricity to become neutral. Interaction of the neutron with matter causes the positive electricity to be transferred, leaving the original cathode ray.

Related to neutron.

cold neutron
A neutron with an energy greater than or equal to 5x10-5 eV and less than or equal to 0.025 eV.

Related to continuum region neutron.
Related to epithermal neutron.
Related to fast neutron.
Related to low energy region neutron.
Related to resonance region neutron.
Related to slow neutron.
Related to thermal neutron.
Related to ultra cold neutron.
Related to very cold neutron.


continuum region neutron
A neutron with an energy between 0.01 MeV and 25 MeV.

Related to cold neutron.
Related to epithermal neutron.
Related to fast neutron.
Related to low energy region neutron.
Related to resonance region neutron.
Related to slow neutron.
Related to thermal neutron.
Related to ultra cold neutron.
Related to very cold neutron.


delayed fission neutron
A neutron emitted by a fission product.

Related to beta-delayed neutron.
Related to fission neutron.
Related to prompt fission neutron.


delayed neutron
Acronym: DN.
See instead beta-delayed neutron.


epithermal neutron
A neutron with an energy greater than 0.025 eV and less than or equal to 1 eV.

Related to cold neutron.
Related to continuum region neutron.
Related to fast neutron.
Related to low energy region neutron.
Related to resonance region neutron.
Related to slow neutron.
Related to thermal neutron.
Related to ultra cold neutron.
Related to very cold neutron.


fast fission
Fission induced by fast neutrons.

Related to fast neutron.

fast neutron
(1) A neutron with an energy considerably greater than thermal energies, sometimes defined as having an energy greater than 1 eV and sometimes defined as having an energy of greater than 100 keV.

(2) A prompt or delayed neutron produced in fission that has not lost appreciable energy.

Related to cold neutron.
Related to continuum region neutron.
Related to epithermal neutron.
Related to low energy region neutron.
Related to resonance region neutron.
Related to slow neutron.
Related to thermal neutron.
Related to ultra cold neutron.
Related to very cold neutron.


fission neutron
A neutron emitted as a nuclide undergoes fission.

Related to delayed fission neutron.
Related to fission.
Related to fission product.
Related to photofission.
Related to prompt fission neutron.
Related to spontaneous fission.
Related to ternary fission.


low energy region neutron
A neutron with an energy below 1 eV.

Related to cold neutron.
Related to continuum region neutron.
Related to epithermal neutron.
Related to fast neutron.
Related to resonance region neutron.
Related to slow neutron.
Related to thermal neutron.
Related to ultra cold neutron.
Related to very cold neutron.


n
A symbol for neutron.

neutron
A basic constituent of the atomic nucleus. The neutron is a fundamental particle, has a mass of 1.008664904 ± 0.000000014 atomic mass units (939.56563 ± 0.00028 MeV). Free, unbound neutrons are produced in fission and in some radioactive decay processes (especially beta decay). A free neutron is unstable, having a half life of 614.6±1.3 s and decaying by β- decay. The neutron is a hadron that is composed of three quarks, udd, and it has a spin-parity of 1/2+ and a magnetic moment of -1.91304275±0.00000045.

Symbol: n.
Related to Bragg neutron.
Related to neutron.
Related to proton.


neutron absorption
A synonym for neutron capture.

neutron absorption cross section
A synonym for neutron absorption cross section.

neutron activation
The process of inducing radioactivity in a sample using the neutron capture reaction.

neutron activation analysis
A method of elemental analysis which uses radiations from neutron-induced radioactivity.

Acronym: NAA.
Synonym: radioactivation analysis.


neutron capture
Absorption of a neutron by an atomic nucleus. A measure of the probability that a material will capture a neutron is given by the neutron capture cross section, which depends on the energy of a neutron and on the composition of the material.

Synonym: neutron absorption.
Related to induced radioactivity.
Related to neutron capture cross section.


neutron-capture cross section
The probability that a neutron passing near a nuclide will be captured or absorbed.

Symbol: σc.
Related to cross section.


neutron chain reaction
A chain reaction that is propagated by neutrons. Neutrons emitted by nuclei in a material are capable of inducing reactions which lead to the production of additional neutrons, thereby sustaining the reaction chain.

Related to chain reaction.
Related to fission.


neutron cycle
A synonym for neutron generation.

neutron generation
A population of neutrons produced during one link in the fission chain reaction. Neutrons in one generation that are successfully moderated and that induce further fission reactions produce a new generation of neutrons.

Synonym: neutron cycle.
Related to chain reaction.
Related to fission.


neutron leakage
Neutrons that escape the moderator of a reactor or a neutron source without undergoing capture by the fissile material or other material in the system.

neutron moderator
A substance used to reduce the energy of neutrons through inelastic scattering. Good moderators have a large scattering cross section and a small absorption cross section. Graphite, water, and heavy water are examples of good neutron moderators.

Synonym: moderator.
Related to capture cross section.
Related to cross section.
Related to scattering cross section.


neutron number
The number of neutrons in a nucleus. It is equivalent to the number of nucleons minus the atomic number or N = (A-Z).

Symbol: N.
Related to atomic number.
Related to mass number.


neutron poison
A synonym for fission poison.

neutron reflector
(1) Material containing elements with a high neutron scattering cross section that is used to reflect neutrons back into a neutron source, thereby increasing the neutron flux inside the source. Beryllium is a common element in reflectors because it has an ultra-high scattering cross section and a very low capture cross section.

(2) A device containing elements with a high neutron scattering cross section that is used to reflect neutrons back into the reactor core, thereby increasing the reactor reactivity and thus the energy output of the reactor.

Synonym: tamper.
Related to neutron capture cross section.
Related to scattering cross section.
Related to reactivity.


neutron separation energy
The energy required to remove one neutron from a nucleus.

Symbol: Sn.
Synonym: neutron binding energy.
Related to binding energy.
Related to nuclear binding energy.
Related to proton separation energy.
Related to separation energy.
Related to total electron binding energy.


prompt fission neutron
A neutron emitted during fission in the formation of the fission fragments.

Related to beta-delayed neutron.
Related to delayed fission neutron.
Related to fission neutron.


resonance region neutron
A neutron with an energy between 1 eV and 0.01 MeV.

Related to cold neutron.
Related to continuum region neutron.
Related to epithermal neutron.
Related to fast neutron.
Related to low energy region neutron.
Related to slow neutron.
Related to thermal neutron.
Related to ultra cold neutron.
Related to very cold neutron.


slow neutron
A neutron with an energy below 1 eV.

Related to cold neutron.
Related to continuum region neutron.
Related to epithermal neutron.
Related to fast neutron.
Related to low energy region neutron.
Related to resonance region neutron.
Related to thermal neutron.
Related to ultra cold neutron.
Related to very cold neutron.


thermal fission
Fission induced by thermal neutrons.

thermal neutron
A neutron with an energy approximately equal to 0.025 eV.

Related to cold neutron.
Related to continuum region neutron.
Related to epithermal neutron.
Related to fast neutron.
Related to low energy region neutron.
Related to resonance region neutron.
Related to slow neutron.
Related to ultra cold neutron.
Related to very cold neutron.


ultra cold neutron
A neutron with an energy less than 2x10-7 eV.

Related to cold neutron.
Related to continuum region neutron.
Related to epithermal neutron.
Related to fast neutron.
Related to low energy region neutron.
Related to resonance region neutron.
Related to slow neutron.
Related to thermal neutron.
Related to very cold neutron.


very cold neutron
A neutron with an energy greater than or equal to 2x10-7 eV and less than 5x10-5 eV.

Related to cold neutron.
Related to continuum region neutron.
Related to epithermal neutron.
Related to fast neutron.
Related to low energy region neutron.
Related to resonance region neutron.
Related to slow neutron.
Related to thermal neutron.
Related to ultra cold neutron.


 
 
Copyright © 2003-2006 Scientific Digital Visions, Inc. All rights reserved.

Our partner sites:
Argus Clearinghouse