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Directional Recoil Identification From Tracks
The Directional Recoil Identification from Tracks (DRIFT) detector is a low pressure negative ion time projection chamber (NITPC) designed to detect weakly interacting massive particles (WIMPs) - a prime dark matter candidate. There are currently two DRIFT detectors in operation. DRIFT-IId, which is located 1100m underground in the Boulby Underground Laboratory at the Boulby Mine in North Yorkshire, England, and DRIFT-IIe, which is located on the surface at Occidental College in Los Angeles. The DRIFT collaboration ultimately aims to develop and operate an underground array of DRIFT detectors for observing and reconstructing WIMP-induced nuclear recoil tracks with enough precision to provide a signature of the dark matter halo. WIMP detection There are numerous experiments worldwide attempting to detect the energy deposition that is expected to occur when a WIMP directly collides with an atom of ordinary matter. Ultra sensitive experiments are required to detect the low energ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ionisation
Ionization or ionisation is the process by which an atom or a molecule acquires a negative or positive charge by gaining or losing electrons, often in conjunction with other chemical changes. The resulting electrically charged atom or molecule is called an ion. Ionization can result from the loss of an electron after collisions with subatomic particles, collisions with other atoms, molecules, electrons, positrons, protons, antiprotons, and ions, or through the interaction with electromagnetic radiation. Heterolytic bond cleavage and heterolytic substitution reactions can result in the formation of ion pairs. Ionization can occur through radioactive decay by the internal conversion process, in which an excited nucleus transfers its energy to one of the inner-shell electrons causing it to be ejected. Uses Everyday examples of gas ionization occur within a fluorescent lamp or other electrical discharge lamps. It is also used in radiation detectors such as the Geiger-Müller ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MWPC
A wire chamber or multi-wire proportional chamber is a type of proportional counter that detects charged particles and photons and can give positional information on their trajectory, by tracking the trails of gaseous ionization. was located via Dr. C.N. BootPHY304 Particle Physics Sheffield University The technique was an improvement over the bubble chamber particle detection method, which used photographic techniques, as it allowed high speed electronics to track the particle path. Description The multi-wire chamber uses an array of wires at a positive dc voltage (anode)s, which run through a chamber with conductive walls held at a lower potential (cathode). The chamber is filled with gas, such as an argon/methane mix, so that any ionizing particle that passes through the tube will ionize surrounding gaseous atoms and produce ion pairs, consisting of positive ions and electrons. These are accelerated by the electric field across the chamber, preventing recombination; the elect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cathode
A cathode is the electrode from which a conventional current leaves a polarized electrical device such as a lead-acid battery. This definition can be recalled by using the mnemonic ''CCD'' for ''Cathode Current Departs''. Conventional current describes the direction in which positive charges move. Electrons, which are the carriers of current in most electrical systems, have a negative electrical charge, so the movement of electrons is ''opposite'' to that of the conventional current flow: this means that electrons flow ''into'' the device's cathode from the external circuit. For example, the end of a household battery marked with a + (plus) is the cathode. The electrode through which conventional current flows the other way, into the device, is termed an anode. Charge flow Conventional current flows from cathode to anode outside the cell or device (with electrons moving in the opposite direction), regardless of the cell or device type and operating mode. Cathode polarity ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electronegative
Electronegativity, symbolized as , is the tendency for an atom of a given chemical element to attract shared electrons (or electron density) when forming a chemical bond. An atom's electronegativity is affected by both its atomic number and the distance at which its valence electrons reside from the charged nucleus. The higher the associated electronegativity, the more an atom or a substituent group attracts electrons. Electronegativity serves as a simple way to quantitatively estimate the bond energy, and the sign and magnitude of a bond's chemical polarity, which characterizes a bond along the continuous scale from covalent to ionic bonding. The loosely defined term electropositivity is the opposite of electronegativity: it characterizes an element's tendency to donate valence electrons. On the most basic level, electronegativity is determined by factors like the nuclear charge (the more protons an atom has, the more "pull" it will have on electrons) and the number and locatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbon Tetrafluoride
Tetrafluoromethane, also known as carbon tetrafluoride or R-14, is the simplest perfluorocarbon (Carbon, CFluorine, F4). As its IUPAC name indicates, tetrafluoromethane is the perfluorinated counterpart to the hydrocarbon methane. It can also be classified as a haloalkane or halomethane. Tetrafluoromethane is a useful refrigerant but also a potent greenhouse gas. It has a very high bond strength due to the nature of the carbon–fluorine bond. Bonding Because of the multiple carbon–fluorine bonds, and the high electronegativity of fluorine, the carbon in tetrafluoromethane has a significant positive partial charge which strengthens and shortens the four carbon–fluorine bonds by providing additional Ionic bond, ionic character. Carbon–fluorine bonds are the strongest single bonds in organic chemistry. Additionally, they strengthen as more carbon–fluorine bonds are added to the same carbon atom. In the one-carbon organofluorine compounds represented by molecules of fluorometh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbon Disulfide
Carbon disulfide (also spelled as carbon disulphide) is an inorganic compound with the chemical formula and structure . It is also considered as the anhydride of thiocarbonic acid. It is a colorless, flammable, neurotoxic liquid that is used as a building block in organic synthesis. Pure carbon disulfide has a pleasant, ether- or chloroform-like odor, but commercial samples are usually yellowish and are typically contaminated with foul-smelling impurities.. History In 1796, the German chemist Wilhelm August Lampadius (1772–1842) first prepared carbon disulfide by heating pyrite with moist charcoal. He called it "liquid sulfur" (''flüssig Schwefel''). The composition of carbon disulfide was finally determined in 1813 by the team of the Swedish chemist Jöns Jacob Berzelius (1779–1848) and the Swiss-British chemist Alexander Marcet (1770–1822). Their analysis was consistent with an empirical formula of CS2. Occurrence, manufacture, properties Small amounts of carbon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drift Chamber
A wire chamber or multi-wire proportional chamber is a type of proportional counter that detects charged particles and photons and can give positional information on their trajectory, by tracking the trails of gaseous ionization. was located via Dr. C.N. BootPHY304 Particle Physics Sheffield University The technique was an improvement over the bubble chamber particle detection method, which used photographic techniques, as it allowed high speed electronics to track the particle path. Description The multi-wire chamber uses an array of wires at a positive dc voltage (anode)s, which run through a chamber with conductive walls held at a lower potential (cathode). The chamber is filled with gas, such as an argon/methane mix, so that any ionizing particle that passes through the tube will ionize surrounding gaseous atoms and produce ion pairs, consisting of positive ions and electrons. These are accelerated by the electric field across the chamber, preventing recombination; the elect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Track Formation
Grading in civil engineering and landscape architectural construction is the work of ensuring a level base, or one with a specified slope, for a construction work such as a foundation, the base course for a road or a railway, or landscape and garden improvements, or surface drainage. The earthworks created for such a purpose are often called the sub-grade or finished contouring (see diagram). Regrading Regrading is the process of grading for raising and/or lowering the levels of land. Such a project can also be referred to as a regrade. Regrading may be done on a small scale (as in preparation of a house site)Trees and Home Construction: Minimizing the impact of construction activity on trees University of Ohio Extension Bulletin 870-99. Accessed online 16 October ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dark Matter Halo
In modern models of physical cosmology, a dark matter halo is a basic unit of cosmological structure. It is a hypothetical region that has decoupled from cosmic expansion and contains gravitationally bound matter. A single dark matter halo may contain multiple virialized clumps of dark matter bound together by gravity, known as subhalos. Modern cosmological models, such as ΛCDM, propose that dark matter halos and subhalos may contain galaxies. The dark matter halo of a galaxy envelops the galactic disc and extends well beyond the edge of the visible galaxy. Thought to consist of dark matter, halos have not been observed directly. Their existence is inferred through observations of their effects on the motions of stars and gas in galaxies and gravitational lensing. Dark matter halos play a key role in current models of galaxy formation and evolution. Theories that attempt to explain the nature of dark matter halos with varying degrees of success include cold dark matter (C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Negative Ion
An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by convention. The net charge of an ion is not zero because its total number of electrons is unequal to its total number of protons. A cation is a positively charged ion with fewer electrons than protons (e.g. K+ (potassium ion)) while an anion is a negatively charged ion with more electrons than protons (e.g. Cl− (chloride ion) and OH− (hydroxide ion)). Opposite electric charges are pulled towards one another by electrostatic force, so cations and anions attract each other and readily form ionic compounds. Ions consisting of only a single atom are termed ''monatomic ions'', ''atomic ions'' or ''simple ions'', while ions consisting of two or more atoms are termed polyatomic ions or ''molecular ions''. If only a + or − is present, it indicates ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Los Angeles
Los Angeles, often referred to by its initials L.A., is the List of municipalities in California, most populous city in the U.S. state of California, and the commercial, Financial District, Los Angeles, financial, and Culture of Los Angeles, cultural center of Southern California. With an estimated 3,878,704 residents within the city limits , it is the List of United States cities by population, second-most populous in the United States, behind only New York City. Los Angeles has an Ethnic groups in Los Angeles, ethnically and culturally diverse population, and is the principal city of a Metropolitan statistical areas, metropolitan area of 12.9 million people (2024). Greater Los Angeles, a combined statistical area that includes the Los Angeles and Riverside–San Bernardino metropolitan areas, is a sprawling metropolis of over 18.5 million residents. The majority of the city proper lies in Los Angeles Basin, a basin in Southern California adjacent to the Pacific Ocean in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
