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SI base unit. s −1. The becquerel (/ ˌbɛkəˈrɛl /; symbol: Bq) is the unit of radioactivity in the International System of Units (SI). One becquerel is defined as an activity of one decay per second. For applications relating to human health this is a small quantity, [1] and SI multiples of the unit are commonly used. [2]
Specific activity. Specific activity (symbol a) is the activity per unit mass of a radionuclide and is a physical property of that radionuclide. [1][2] It is usually given in units of becquerel per kilogram (Bq/kg), but another commonly used unit of specific activity is the curie per gram (Ci/g). In the context of radioactivity, activity or ...
3.7×1010 s −1. Sample of cobalt-60 that emits 1 μCi (microcurie) of radioactivity; i.e. 37,000 decays per second. The curie (symbol Ci) is a non- SI unit of radioactivity originally defined in 1910. According to a notice in Nature at the time, it was to be named in honour of Pierre Curie, [ 1 ] but was considered at least by some to be in ...
Disintegrations per minute (dpm) and disintegrations per second (dps) are measures of the activity of the source of radioactivity. The SI unit of radioactivity, the becquerel (Bq), is equivalent to one disintegration per second. This unit should not be confused with cps, which is the number of counts received by an instrument from the source.
Radiation dosimetry in the fields of health physics and radiation protection is the measurement, calculation and assessment of the ionizing radiation dose absorbed by an object, usually the human body. This applies both internally, due to ingested or inhaled radioactive substances, or externally due to irradiation by sources of radiation.
The relative activity of a species i, denoted a i, is defined [4] [5] as: = where μ i is the (molar) chemical potential of the species i under the conditions of interest, μ o i is the (molar) chemical potential of that species under some defined set of standard conditions, R is the gas constant, T is the thermodynamic temperature and e is the exponential constant.
Antoine Henri Becquerel (/ ˌbɛkəˈrɛl /; [3] French: [ɑ̃twan ɑ̃ʁi bɛkʁɛl]; 15 December 1852 – 25 August 1908) was a French engineer, physicist, Nobel laureate, and the first person to discover radioactivity. For work in this field he, along with Marie Skłodowska-Curie and Pierre Curie, [4] received the 1903 Nobel Prize in Physics.
Total activity (or just activity), A, is the number of decays per unit time of a radioactive sample. Number of particles, N, in the sample. Specific activity, a, is the number of decays per unit time per amount of substance of the sample at time set to zero (t = 0). "Amount of substance" can be the mass, volume or moles of the initial sample.