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Area Radiology and radiological physics / Ionizing radiations : quantities and units

IEV ref881-04-42

Symbol
A

en
activity
of an amount of a radionuclide in a particular energy state at a given time, the quotient of dN by dt, where dN is the expectation value of the number of spontaneous nuclear transitions from that energy state in the time interval dt:

A= dN dt MathType@MTEF@5@5@+=feaagCart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbbjxAHXgaruavP1wzZbItLDhis9wBH5garmWu51MyVXgarqqtubsr4rNCHbGeaGqipG0dh9qqWrVepG0dbbL8F4rqqrVepeea0xe9LqFf0xc9q8qqaqFn0lXdHiVcFbIOFHK8Feea0dXdar=Jb9hs0dXdHuk9fr=xfr=xfrpeWZqaaeaaciWacmGadaGadeaabaGaaqaaaOqaaiaadgeacqGH9aqpdaWcaaqaaiaabsgacaWGobaabaGaaeizaiaadshaaaaaaa@3AC4@

Note – The SI unit of activity is the reciprocal second (s−1) and is given the special name becquerel (Bq). The earlier special unit of activity, still in temporary use, was the curie (Ci). 1 Bq = 1 s−1 = 2,703 × 10−11 Ci approximately.


fr
activité (nucléaire) f
pour une certaine quantité de radionucléide, à un niveau d'énergie considéré et à un instant donné, quotient de dN par dt, où dN est le nombre de transitions nucléaires qui se produisent au sein d'un radionucléide, à partir de ce niveau d'énergie, pendant le temps dt:

A= dN dt MathType@MTEF@5@5@+=feaagCart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbbjxAHXgaruavP1wzZbItLDhis9wBH5garmWu51MyVXgarqqtubsr4rNCHbGeaGqipG0dh9qqWrVepG0dbbL8F4rqqrVepeea0xe9LqFf0xc9q8qqaqFn0lXdHiVcFbIOFHK8Feea0dXdar=Jb9hs0dXdHuk9fr=xfr=xfrpeWZqaaeaaciWacmGadaGadeaabaGaaqaaaOqaaiaadgeacqGH9aqpdaWcaaqaaiaabsgacaWGobaabaGaaeizaiaadshaaaaaaa@3AC4@

Note – L'unité SI d'activité (s−1) est le becquerel (Bq). L'ancienne unité d'activité encore utilisée temporairement est le curie (Ci). 1 Bq = 1 s−1 = 2,703 × 10−11 Ci approximativement.


ar
نشاط

es
actividad (nuclear)

it
attività

ko
활동도

ja
活量

pl
aktywność

pt
actividade (nuclear)

sv
aktivitet

Publication date: 1983-01
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