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Clover (detector)
A clover detector is a gamma-ray detector that consists of 4 coaxial N-type high purity germanium (Ge) crystals each machined to shape and mounted in a common cryostat to form a structure resembling a four-leaf clover. The clover is the first composite Ge detector. It remains widely used in the detectors of particle accelerators, where multiple clover modules form an array all around the target to capture the rays. More complex composite detectors, such as the 7-element hexagonal cluster detector used on the Euroball, offer even better data. Operation A gamma ray may interact with a single Ge crystal and deposit its full energy. The resulting charge collected will then be proportional to this energy. However, through the process of Compton scattering, a gamma ray may interact with two (or possibly more) crystals resulting in the energy (and thus the liberated charge) being shared by the crystals. In this case, a process known as add-back, where the charge collected by each of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gamma Spectroscopy
Gamma-ray spectroscopy is the ''qualitative'' study of the energy spectra of gamma-ray sources, such as in the nuclear industry, geochemical investigation, and astrophysics. Gamma-ray spectrometry, on the other hand, is the method used to acquire a ''quantitative'' spectrum measurement. Most radioactive sources produce gamma rays, which are of various energies and intensities. When these emissions are detected and analyzed with a spectroscopy system, a gamma-ray energy spectrum can be produced. A detailed analysis of this spectrum is typically used to determine the identity and quantity of gamma emitters present in a gamma source, and is a vital tool in radiometric assay. The gamma spectrum is characteristic of the gamma-emitting nuclides contained in the source, just like in an optical spectrometer, the optical spectrum is characteristic of the material contained in a sample. Gamma ray characteristics Gamma rays are the highest-energy form of electromagnetic radiation, being ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
N-type Semiconductor
N-type, N type or Type N may refer to: * N-type semiconductor is a key material in the manufacture of transistors and integrated circuits * An N-type connector is a threaded RF connector used to join coaxial cables * The MG N-type Magnette was produced by the MG Car company from October 1934 to 1936 * The N-type calcium channel is a type of voltage-dependent calcium channel * A Type (model theory) with n free variables * The Dennis N-Type vehicle chassis was used to build fire engines and trucks * The N type carriage The N type carriages are an intercity Passenger car (rail), passenger carriage used on the Rail transport in Victoria, railways of Victoria, Australia. They were introduced between 1981 and 1984 as part of the 'New Deal (railway), New Deal' re ... is an intercity passenger carriage used on the railways of Victoria, Australia * The REP Type N was a military reconnaissance aircraft produced in France in 1914 * N type battery, see: N battery * Type N power plu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Germanium
Germanium is a chemical element; it has Symbol (chemistry), symbol Ge and atomic number 32. It is lustrous, hard-brittle, grayish-white and similar in appearance to silicon. It is a metalloid or a nonmetal in the carbon group that is chemically similar to silicon. Like silicon, germanium naturally Chemical reaction, reacts and forms complexes with oxygen in nature. Because it seldom appears in high concentration, germanium was found comparatively late in the Timeline of chemical element discoveries, discovery of the elements. Germanium ranks 50th Abundance of elements in Earth's crust, in abundance of the elements in the Earth's crust. In 1869, Dmitri Mendeleev Mendeleev's predicted elements, predicted its existence and some of its Chemical property, properties from its position on his periodic table, and called the element ekasilicon. On February 6, 1886, Clemens Winkler at Freiberg University found the new element, along with silver and sulfur, in the mineral argyrodite. Winkle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cryostat
A cryostat (from ''cryo'' meaning cold and ''stat'' meaning stable) is a device used to maintain low cryogenic temperatures of samples or devices mounted within the cryostat. Low temperatures may be maintained within a cryostat by using various refrigeration methods, most commonly using cryogenic fluid bath such as liquid helium.Frank Pobell: ''Matter and Methods at Low Temperatures''. 3rd Edition, Springer 2007, Hence it is usually assembled into a vessel, similar in construction to a vacuum flask or Dewar. Cryostats have numerous applications within science, engineering, and medicine. Types Closed-cycle cryostats Closed-cycle cryostats consist of a chamber through which cold helium vapour is pumped. An external mechanical refrigerator extracts the warmer helium exhaust vapour, which is cooled and recycled. Closed-cycle cryostats consume a relatively large amount of electrical power, but need not be refilled with helium and can run continuously for an indefinite perio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Four-leaf Clover
The four-leaf clover is a rare mutation of the common three-leaf clover that has four Leaflet (botany), leaflets instead of three. According to traditional sayings, such clovers bring good luck, a belief that dates back to at least the 17th century. The term ''four-leaf'' is Botany, botanically a misnomer, as Clover, cloverplants have multiple leaves (multiple clovers), each consisting of a varying number of Leaflet (botany), leaflets, typically three. Occurrence A 2017 survey of approximately 5.7 million clovers in six European countries found the frequency of 4-leaf clovers to be around 5000 to 1 (one 4-leaf clover for every 5076 normal 3-leaf clovers), almost twice the commonly stated probability of 10,000 to 1. According to this survey, the frequency of a 5-leaf clover is 24,390 to 1, and that of a 6-leaf clover is 312,500 to 1. According to Guinness World Records, the clover with the most leaflets ever found had 63 of them, and was discovered by Yoshiharu Watanabe of Nas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Compton Scattering
Compton scattering (or the Compton effect) is the quantum theory of high frequency photons scattering following an interaction with a charged particle, usually an electron. Specifically, when the photon hits electrons, it releases loosely bound electrons from the outer valence shells of atoms or molecules. The effect was discovered in 1923 by Arthur Holly Compton while researching the scattering of X-rays by light elements, and earned him the Nobel Prize in Physics in 1927. The Compton effect significantly deviated from dominating classical theories, using both special relativity and quantum mechanics to explain the interaction between high frequency photons and charged particles. Photons can interact with matter at the atomic level (e.g. photoelectric effect and Rayleigh scattering), at the nucleus, or with just an electron. Pair production and the Compton effect occur at the level of the electron. When a high frequency photon scatters due to an interaction with a charged part ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Compton Suppression
Electronic anticoincidence is a method (and its associated hardware) widely used to suppress unwanted, "background" events in high energy physics, experimental particle physics, gamma-ray spectroscopy, gamma-ray astronomy, experimental nuclear physics, and related fields. In the typical case, a desired high-energy interaction or event occurs and is detected by some kind of detector, creating a fast electronic pulse in the associated nuclear electronics. But the desired events are mixed up with a significant number of other events, produced by other particles or processes, which create indistinguishable events in the detector. Very often it is possible to arrange other physical photon or particle detectors to intercept the unwanted background events, producing essentially simultaneous pulses that can be used with fast electronics to reject the unwanted background. Gamma-ray astronomy Early experimenters in X-ray and gamma-ray astronomy found that their detectors, flown on bal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Germanium Detector
In ionizing radiation detection physics, a semiconductor detector is a device that uses a semiconductor (usually silicon or germanium) to measure the effect of incident charged particles or photons. Semiconductor detectors find broad application for radiation protection, gamma and X-ray spectrometry, and as particle detectors. Detection mechanism In semiconductor detectors, ionizing radiation is measured by the number of charge carriers set free in the detector material which is arranged between two electrodes, by the radiation. Ionizing radiation produces free electrons and electron holes. The number of electron-hole pairs is proportional to the energy of the radiation to the semiconductor. As a result, a number of electrons are transferred from the valence band to the conduction band, and an equal number of holes are created in the valence band. Under the influence of an electric field, electrons and holes travel to the electrodes, where they result in a pulse that can be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Doppler Broadening
In atomic physics, Doppler broadening is broadening of spectral lines due to the Doppler effect caused by a distribution of velocities of atoms or molecules. Different velocities of the emitting (or absorbing) particles result in different Doppler shifts, the cumulative effect of which is the emission (absorption) line broadening. This resulting line profile is known as a Doppler profile. A particular case is the thermal Doppler broadening due to the thermal motion of the particles. Then, the broadening depends only on the frequency of the spectral line, the mass of the emitting particles, and their temperature, and therefore can be used for inferring the temperature of an emitting (or absorbing) body being spectroscopically investigated. Derivation (non-relativistic case) When a particle moves (e.g., due to the thermal motion) towards the observer, the emitted radiation is shifted to a higher frequency. Likewise, when the emitter moves away, the frequency is lowered. In th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Compton Polarimetry
Compton may refer to: Places Canada * Compton (federal electoral district), a former Quebec federal electoral district * Compton (provincial electoral district), a former Quebec provincial electoral district now part of Mégantic-Compton * Compton, Quebec * Compton County, Quebec * Compton Creek, a tributary of the Adam River on Vancouver Island, British Columbia * Compton Island, in the Queen Charlotte Strait region of British Columbia * Compton Névé, a névé (icefield) in the Pacific Ranges, British Columbia ** Compton Glacier, a glacier in the Compton Névé, Pacific Ranges, British Columbia ** Compton Mountain, a mountain in the Compton Névé, Pacific Ranges, British Columbia England * Compton, Berkshire * Compton, Derbyshire, a location in Ashbourne parish * Compton, Plymouth, Devon * Compton, South Hams, a location * Compton, Test Valley, a location * Compton, Hampshire, in Winchester district * Compton, Staffordshire, a location * Compton, Guildford, Surrey ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spectrometers
A spectrometer () is a scientific instrument used to separate and measure Spectrum, spectral components of a physical phenomenon. Spectrometer is a broad term often used to describe instruments that measure a continuous variable of a phenomenon where the spectral components are somehow mixed. In visible light a spectrometer can separate white light and measure individual narrow bands of color, called a spectrum. A mass spectrometer measures the spectrum of the masses of the atoms or molecules present in a gas. The first spectrometers were used to split light into an array of separate colors. Spectrometers were History_of_spectroscopy, developed in early studies of physics, astronomy, and chemistry. The capability of spectroscopy to determine Analytical_chemistry#Spectroscopy, chemical composition drove its advancement and continues to be one of its primary uses. Spectrometers are used in Astronomical spectroscopy, astronomy to analyze the chemical composition of Astronomical_spe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
