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Becquerel
The becquerel (; symbol: Bq) is the unit of radioactivity in the International System of Units (SI). One becquerel is defined as the activity of a quantity of radioactive material in which one nucleus decays per second. For applications relating to human health this is a small quantity, and SI multiples of the unit are commonly used. The becquerel is named after Henri Becquerel, who shared a Nobel Prize in Physics with Pierre and Marie Skłodowska Curie in 1903 for their work in discovering radioactivity. Definition 1 Bq = 1 s−1 A special name was introduced for the reciprocal second (s−1) to represent radioactivity to avoid potentially dangerous mistakes with prefixes. For example, 1 µs−1 would mean 106 disintegrations per second: 1·(10−6 s)−1 = 106 s−1, whereas 1 µBq would mean 1 disintegration per 1 million seconds. Other names considered were hertz (Hz), a special name already in use for the reciprocal second, and Four ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Henri Becquerel
Antoine Henri Becquerel (; 15 December 1852 – 25 August 1908) was a French engineer, physicist, Nobel laureate, and the first person to discover evidence of radioactivity. For work in this field he, along with Marie Skłodowska-Curie and Pierre Curie, received the 1903 Nobel Prize in Physics. The SI unit for radioactivity, the becquerel (Bq), is named after him. Biography Early life Becquerel was born in Paris, France, into a wealthy family which produced four generations of physicists: Becquerel's grandfather ( Antoine César Becquerel), father ( Alexandre-Edmond Becquerel), and son (Jean Becquerel). Henri started off his education by attending the Lycée Louis-le-Grand school, a prep school in Paris. He studied engineering at the École Polytechnique and the École des Ponts et Chaussées. In 1874, Henri married Lucie Zoé Marie Jamin, who would die while giving birth to their son, Jean. In 1890 he married Louise Désirée Lorieux. Career In Becquerel's early career, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Specific Activity
Specific activity is the activity per unit mass of a radionuclide and is a physical property of that radionuclide. Activity is a quantity (for which the SI unit is the becquerel) related to radioactivity, and is defined as the number of radioactive transformations per second that occur in a particular radionuclide. The unit of activity is the becquerel (Bq), which is defined as one radioactive decay per second. The older, non-SI unit of activity is the curie (Ci), which is radioactive decay per second. Another unit of activity is the Rutherford, which is defined as radioactive decay per second. Since the probability of radioactive decay for a given radionuclide within a set time interval is fixed (with some slight exceptions, see changing decay rates), the number of decays that occur in a given time of a given mass (and hence a specific number of atoms) of that radionuclide is also a fixed (ignoring statistical fluctuations). Thus, specific activity is defined as the acti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rutherford (unit)
The rutherford (symbol Rd) is a non-SI unit of radioactive decay. It is defined as the activity of a quantity of radioactive material in which one million nuclei decay per second. It is therefore equivalent to one megabecquerel, and one becquerel equals one microrutherford. One rutherford is equivalent to 2.703 × 10−5 curie. The unit was introduced in 1946. It was named after British/New Zealand physicist and Nobel laureate Lord Ernest Rutherford (Nobel Prize in 1908), who was an early leader in the study of atomic nucleus The atomic nucleus is the small, dense region consisting of protons and neutrons at the center of an atom, discovered in 1911 by Ernest Rutherford based on the 1909 Geiger–Marsden gold foil experiment. After the discovery of the neutron ... disintegrations. After the becquerel was introduced in 1975 as the SI unit for activity, the rutherford became obsolete, and it is no longer commonly used. Radiation related quantities The following table sho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rutherford (unit)
The rutherford (symbol Rd) is a non-SI unit of radioactive decay. It is defined as the activity of a quantity of radioactive material in which one million nuclei decay per second. It is therefore equivalent to one megabecquerel, and one becquerel equals one microrutherford. One rutherford is equivalent to 2.703 × 10−5 curie. The unit was introduced in 1946. It was named after British/New Zealand physicist and Nobel laureate Lord Ernest Rutherford (Nobel Prize in 1908), who was an early leader in the study of atomic nucleus The atomic nucleus is the small, dense region consisting of protons and neutrons at the center of an atom, discovered in 1911 by Ernest Rutherford based on the 1909 Geiger–Marsden gold foil experiment. After the discovery of the neutron ... disintegrations. After the becquerel was introduced in 1975 as the SI unit for activity, the rutherford became obsolete, and it is no longer commonly used. Radiation related quantities The following table sho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Curie (unit)
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, but was considered at least by some to be in honour of Marie Curie as well, and is in later literature considered to be named for both. It was originally defined as "the quantity or mass of radium emanation in equilibrium with one gram of radium (element)", but is currently defined as 1 Ci = decays per second after more accurate measurements of the activity of 226Ra (which has a specific activity of ). In 1975 the General Conference on Weights and Measures gave the becquerel (Bq), defined as one nuclear decay per second, official status as the SI unit of activity. Therefore: : 1 Ci = = 37 GBq and : 1 Bq ≅ ≅ 27 pCi While its continued use is discouraged by National Institute of Standards and Technology (NIST) and other bodies, the curie is still widely used throughout ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radioactive Decay
Radioactive decay (also known as nuclear decay, radioactivity, radioactive disintegration, or nuclear disintegration) is the process by which an unstable atomic nucleus loses energy by radiation. A material containing unstable nuclei is considered radioactive. Three of the most common types of decay are alpha decay ( ), beta decay ( ), and gamma decay ( ), all of which involve emitting one or more particles. The weak force is the mechanism that is responsible for beta decay, while the other two are governed by the electromagnetism and nuclear force. A fourth type of common decay is electron capture, in which an unstable nucleus captures an inner electron from one of the electron shells. The loss of that electron from the shell results in a cascade of electrons dropping down to that lower shell resulting in emission of discrete X-rays from the transitions. A common example is iodine-125 commonly used in medical settings. Radioactive decay is a stochastic (i.e. random) pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cycle Per Second
The cycle per second is a once-common English name for the unit of frequency now known as the hertz (Hz). The plural form was typically used, often written cycles per second, cycles/second, c.p.s., c/s, or, ambiguously, just cycles (Cy./Cyc.). The term comes from the fact that sound waves have a frequency measurable in their number of oscillations, or '' cycles'', per second. With the organization of the International System of Units in 1960, the cycle per second was officially replaced by the hertz, or reciprocal second, "s−1" or "1/s". Symbolically, "cycle per second" units are "cycle/second", while hertz is "Hz" or "s−1". For higher frequencies, ''kilocycles'' (kc), as an abbreviation of ''kilocycles per second'' were often used on components or devices. Other higher units like ''megacycle'' (Mc) and less commonly ''kilomegacycle'' (kMc) were used before 1960 and in some later documents. These have modern equivalents such as kilohertz (kHz), megahertz (MHz), and gigahertz ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Activity (radioactivity)
Radioactive decay (also known as nuclear decay, radioactivity, radioactive disintegration, or nuclear disintegration) is the process by which an unstable atomic nucleus loses energy by radiation. A material containing unstable nuclei is considered radioactive. Three of the most common types of decay are alpha decay ( ), beta decay ( ), and gamma decay ( ), all of which involve emitting one or more particles. The weak force is the mechanism that is responsible for beta decay, while the other two are governed by the electromagnetism and nuclear force. A fourth type of common decay is electron capture, in which an unstable nucleus captures an inner electron from one of the electron shells. The loss of that electron from the shell results in a cascade of electrons dropping down to that lower shell resulting in emission of discrete X-rays from the transitions. A common example is iodine-125 commonly used in medical settings. Radioactive decay is a stochastic (i.e. random) proces ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inverse Second
The inverse second or reciprocal second (s−1) is a unit of frequency, defined as the multiplicative inverse of the second (a unit of time). It is dimensionally equivalent to: * the unit hertz – the SI unit for frequency * the unit radian per second – the SI unit for angular frequency and angular velocity * the unit becquerel – the SI unit for the rate of occurrence of aperiodic or stochastic radionuclide events * the unit baud – the unit for symbol rate over a communication link * the unit of strain rate. See also *Aperiodic frequency *Inverse metre *Unit of time References *''"The SI unit of frequency is given as the hertz, implying the unit cycles per second; the SI unit of angular velocity is given as the radian per second; and the SI unit of activity is designated the becquerel, implying the unit counts per second. Although it would be formally correct to write all three of these units as the reciprocal second, the use of the different names emphasises the different ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pierre Curie
Pierre Curie ( , ; 15 May 1859 – 19 April 1906) was a French physicist, a pioneer in crystallography, magnetism, piezoelectricity, and radioactivity. In 1903, he received the Nobel Prize in Physics with his wife, Marie Curie, and Henri Becquerel, "in recognition of the extraordinary services they have rendered by their joint researches on the radiation phenomena discovered by Professor Henri Becquerel". With their win, the Curies became the first ever married couple to win the Nobel Prize, launching the Curie family legacy of five Nobel Prizes. Early life Born in Paris on 15 May 1859, Pierre Curie was the son of Eugène Curie (1827–1910), a doctor of French Catholic origin from Alsace, and Sophie-Claire Curie (née Depouilly; 1832–1897). He was educated by his father and in his early teens showed a strong aptitude for mathematics and geometry. When he was 16, he earned his Bachelor of Science in mathematics. By the age of 18, he earned his license, the equivalent of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SI Prefix
The International System of Units, known by the international abbreviation SI in all languages and sometimes pleonastically as the SI system, is the modern form of the metric system and the world's most widely used system of measurement. Established and maintained by the General Conference on Weights and Measures (CGPM), it is the only system of measurement with an official status in nearly every country in the world, employed in science, technology, industry, and everyday commerce. The SI comprises a coherent system of units of measurement starting with seven base units, which are the second (symbol s, the unit of time), metre (m, length), kilogram (kg, mass), ampere (A, electric current), kelvin (K, thermodynamic temperature), mole (mol, amount of substance), and candela (cd, luminous intensity). The system can accommodate coherent units for an unlimited number of additional quantities. These are called coherent derived units, which can always be represented ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hertz
The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), equivalent to one event (or cycle) per second. The hertz is an SI derived unit whose expression in terms of SI base units is s−1, meaning that one hertz is the reciprocal of one second. It is named after Heinrich Rudolf Hertz (1857–1894), the first person to provide conclusive proof of the existence of electromagnetic waves. Hertz are commonly expressed in multiples: kilohertz (kHz), megahertz (MHz), gigahertz (GHz), terahertz (THz). Some of the unit's most common uses are in the description of periodic waveforms and musical tones, particularly those used in radio- and audio-related applications. It is also used to describe the clock speeds at which computers and other electronics are driven. The units are sometimes also used as a representation of the energy of a photon, via the Planck relation ''E'' = ''hν'', where ''E'' is the photon's energy, ''ν'' is its ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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