TERMIUM Plus®

The Government of Canada’s terminology and linguistic data bank.

UNSTABLE NUCLEUS [7 records]

Filter results by subject field Alphabetical list of terms

Filter results by subject field

Alphabetical list of terms

Record 1 2023-10-17

English

Subject field(s)
  • Atomic Physics
  • Space Physics
DEF

A hypothetical type of decay occurring when a neutron located in the halo of a nucleus ejects a proton.

CONT

... there [is] a theory, a very hypothetical idea, that you could observe dark matter with a very particular type of nucleus... This theory centered on what it calls a dark decay. It posited that certain unstable nuclei, nuclei that naturally fall apart, could jettison dark matter as they crumbled.

French

Domaine(s)
  • Physique atomique
  • Physique spatiale

Spanish

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Record 2 2023-02-27

English

Subject field(s)
  • Atomic Physics
  • Nuclear Science and Technology
CONT

Activation occurs when a particle interacts with an atomic nucleus, shifting the nucleus into an unstable state, and causing it to become radioactive.

French

Domaine(s)
  • Physique atomique
  • Sciences et techniques nucléaires
DEF

Processus par lequel un nucléide stable est transformé en un nucléide radioactif.

OBS

radioactivation; activation : désignations et définition publiées au Journal officiel de la République française le 21 septembre 2005.

Spanish

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Record 3 2012-01-30

English

Subject field(s)
  • Radiography (Medicine)
DEF

The process of producing a scintigram.

CONT

In isotope scanning, radioactive isotopes are introduced into the body and their distribution is then determined by observations of their radioaction. ... [The] isotopes ... are usually emitters of gamma rays only. ... The radiation emitted is detected by a scintillation counter, which is moved to and fro over the organ ... being scanned; these messages can then be electronically recorded as marks on paper or as a photographic image.

OBS

A radioisotope is a specific type of radioactive substance; a radioisotope is a radioactive isotope of an element. Its unstable atomic nucleus undergoes radioactive decay and emits alpha, beta or gamma rays. Most isotopes however are emitters of gamma rays only. Since a radioisotope is a specific type of radioactive substance, radioisotope scanning is specific with respect to radioactive scanning(in French, scintigraphie).

French

Domaine(s)
  • Radiographie (Médecine)
DEF

Radiographie consistant à injecter, généralement par voie intraveineuse, une solution radioactive qui a une affinité élective pour l'organe examiné, puis à déterminer, à l'aide d'un détecteur placé à l'extérieur, la répartition topographique de la radioactivité dans les différentes parties de l'organe.

Key term(s)
  • radioisotopie
  • radiologie isotopique

Spanish

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Record 4 - external organization data 2006-03-24

English

Subject field(s)
  • Atomic Physics
  • Compartment - Canadian Nuclear Safety Commission
CONT

Although isotopes exhibit nearly identical electronic and chemical behavior, their nuclear behavior varies dramatically. Atomic nuclei consist of protons and neutrons bound together by the strong nuclear force. Because protons are positively charged, they repel each other. Neutrons, which are electrically neutral, allow some separation between the positively charged protons, reducing the electrostatic repulsion and stabilizing the nucleus. For this reason neutrons are necessary for two or more protons to be bound into a nucleus. As the number of protons increases, additional neutrons are needed to form a stable nucleus; for example, although the neutron/proton ratio of3He is 1/2, the neutron/proton ratio of238U is greater than 3/2. If too many neutrons or too few neutrons are present, the nucleus becomes unstable and subject to nuclear decay.

French

Domaine(s)
  • Physique atomique
  • Tiroir - Commission canadienne de sûreté nucléaire
Key term(s)
  • rapport neutron proton

Spanish

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Record 5 - external organization data 2005-07-15

English

Subject field(s)
  • Atomic Physics
  • Compartment - Canadian Nuclear Safety Commission
CONT

Excited states are not the same as unstable nuclides. An excited nucleus has excess energy.

French

Domaine(s)
  • Physique atomique
  • Tiroir - Commission canadienne de sûreté nucléaire
CONT

Il existe une différence entre un noyau dans un état excité et un noyau instable. Les noyaux excités ont un excès d'énergie.

Spanish

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Record 6 2003-11-21

English

Subject field(s)
  • Geochemistry
  • Chronology
DEF

Applied to certain unstable atoms, the nuclei of which spontaneously disintegrate emitting particles and rays, eventually reverting through a series of such emissions into an atom having a stable nucleus and a different atomic number.

CONT

Radioactive elements include radium, uranium, and a number of newly discovered, short-lived elements (as californium, berkelium, etc.).

French

Domaine(s)
  • Géochimie
  • Chronologie
CONT

Beaucoup [de] roches contiennent d'infimes quantités des éléments dits radioactifs (uranium et thorium) qui, on le sait, sont instables et se désintègrent lentement selon un processus qui, au bout de milliards d'années, donne un produit final analogue au plomb ordinaire.

Spanish

Campo(s) temático(s)
  • Geoquímica
  • Cronología
Save record 6

Record 7 1999-03-25

English

Subject field(s)
  • Atomic Physics
OBS

Beta Emission is a nuclear decay process. It is the process that ejects a high speed electron from an unstable nucleus.

French

Domaine(s)
  • Physique atomique
CONT

Il n'est pas actuellement possible de déterminer la stabilité, c'est-à-dire la durée de vie d'un noyau ab initio, en fonction du nombre de ses nucléons, aussi, pour déterminer les lois de stabilité, les physiciens produisent-ils des noyaux instables dont ils étudient les propriétés. Pour ce faire, ils bombardent une cible avec des noyaux (généralement des ions accélérés par un champ électrique ) pour créer ces noyaux nouveaux [...] les propriétés de ces noyaux, masse, temps de vie, rayon nucléaire moyen, voies de désintégration, sections efficaces de réactions, ouvrent la porte à une nouvelle physique nucléaire, celle des noyaux instables.

Spanish

Save record 7

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