Becquerel (unit)
Physical unit | |
---|---|
Unit name | Becquerel |
Unit symbol | |
Physical quantity (s) | activity |
Formula symbol | |
dimension | |
system | International system of units |
In SI units | |
Named after | Antoine Henri Becquerel |
Derived from | second |
Becquerel [ bɛkə'rɛl ], abbreviated to Bq, is the SI unit of the activity of a certain amount of a radioactive substance. The average number of atomic nuclei that decay radioactively per second is given:
- 1 Bq = 1 s ^{−1} (i.e. one Becquerel corresponds to one radioactive decay per second)
Since 1 Bq is an extremely low activity, very large numerical values occur in practice. Therefore one often uses prefixes for the order of magnitude (mega-, giga-, tera-, ...).
The unit is named after the French physicist Antoine Henri Becquerel , who together with Pierre Curie and Marie Curie received the Nobel Prize for the discovery of radioactivity in 1903 . The Becquerel was adopted in 1975 at the 15th meeting of the General Conference on Weights and Measures as a derived SI unit with a special name in the International System of Units.
Relation to other units
The Becquerel unit replaces the Curie in the International System of Units (SI) . The following relationship exists between these two units:
- 1 Ci = 3.7 x 10 ^{10} Bq
- 1 Bq = 2.7 027 · 10 ^{−11} Ci
The following relationship also applies:
- 1 Bq = 60 dpm ("disintegrations per minute", disintegrations per minute)
The units Rutherford (1 rd = 10 ^{6} Bq) and Stat (1 Stat = 1.345 · 10 ^{4} Bq) are further outdated, non- SI -conforming units for the activity.
At first glance, the Becquerel appears to be identical to the Hertz unit , both are defined as . The difference between the two is that Becquerel measures the mean frequency of a random event (such as radioactive decay), while Hertz measures a non-random, periodic quantity (such as the frequency of a radio wave).
Individual evidence
- ↑ Hanno Krieger: Fundamentals of radiation physics and radiation protection. 3rd, revised and expanded edition. Vieweg + Teubner, Wiesbaden 2009, ISBN 978-3-8348-0801-1 , Chapter 3.2.1 Activity definitions .
- ↑ Resolution 8 at the 15th meeting of the Conférence Générale des Poids et Mesures 1975 (accessed on March 3, 2013).