activation analysis

(redirected from activation analyses)
Also found in: Dictionary, Encyclopedia.

ac·ti·va·tion a·nal·y·sis

the identification and quantification of unknown elements from their characteristic emissions and decay constants after they have been made radioactive by exposure to neutron or charged particle radiation.

neutron activation analysis

A method for identifying and measuring the concentrations of the chemical elements in a large and complex sample of material.

Method
A sample is rendered radioactive by bombarding it with neutrons, charged particles or gamma rays, making the nuclei of the different elements unstable and radioactive, and putting them in a higher energy state. Each of the now-radioactive isotopes in the sample gives off a characteristic signature (e.g., alpha particles, gamma rays), which indicates the type and concentration of the elements in the sample.

activation

the process of activating.

activation analysis
a method of analyzing the content of elements in samples of biological material. The sample is bombarded with nuclear particles and the elements in it measured by the radiation emitted by their radioactive daughter products. Called also radioactivation analysis.
activation energy
the difference in energy between the ground state of the reactants in a reaction and the point of maximum energy or transition state of the reactions. Usually lowered by enzyme catalysts.
activation factor
activation unit
the combination of complement (C4, C2 and C3) that binds to the antigen-antibody complex in the initial reaction step in the classical pathway of complement activation. See also complement.