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HERA (particle Accelerator)
HERA (german: Hadron-Elektron-Ringanlage, en, Hadron-Electron Ring Accelerator) was a particle accelerator at DESY in Hamburg. It began operating in 1992. At HERA, electrons or positrons were collided with protons at a center of mass energy of 318 GeV. It was the only lepton- proton collider in the world while operating. Also, it was on the energy frontier in certain regions of the kinematic range. HERA was closed down on 30 June 2007. The HERA tunnel is located under the DESY site and the nearby Volkspark around 15 to 30 m underground and has a circumference of 6.3 km. Leptons and protons were stored in two independent storage rings on top of each other inside this tunnel. There are four interaction regions, which were used by the experiments '' H1'', ''ZEUS'', ''HERMES'' and '' HERA-B''. All these experiments were particle detectors. Leptons (electrons or positrons) were pre-accelerated to 450 MeV in the linear accelerator ''LINAC-II''. From there they were inje ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Particle Accelerator
A particle accelerator is a machine that uses electromagnetic fields to propel charged particles to very high speeds and energies, and to contain them in well-defined beams. Large accelerators are used for fundamental research in particle physics. The largest accelerator currently active is the Large Hadron Collider (LHC) near Geneva, Switzerland, operated by the CERN. It is a collider accelerator, which can accelerate two beams of protons to an energy of 6.5 TeV and cause them to collide head-on, creating center-of-mass energies of 13 TeV. Other powerful accelerators are, RHIC at Brookhaven National Laboratory in New York and, formerly, the Tevatron at Fermilab, Batavia, Illinois. Accelerators are also used as synchrotron light sources for the study of condensed matter physics. Smaller particle accelerators are used in a wide variety of applications, including particle therapy for oncological purposes, radioisotope production for medical diagnostics, ion ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HERMES Experiment
HERMES was an experiment conducted using the HERA particle accelerator located at the German national laboratory DESY in Hamburg. The experiment's goal was to investigate the quark-gluon structure of matter by examining how a nucleon's constituents affect its spin. It later developed into a pioneering experiment for measuring generalised parton parton distributions and a general-purpose experiment for the study of QCD processes. HERMES completed its first run between 1995 and 2000, and a second run began in 2001 and ended during the summer of 2007. HERMES was conducted by scientists from more than 13 countries. Method Polarized electrons are fired at polarized gas targets. The virtual photon emitted by the electron was also polarized and sought out quarks of spin in the opposite direction as the photon. The asymmetry of ejected quarks was determined to deduce the net polarisation of the quarks. UGFS The unpolarized gas feed system (UGFS) was used for non polarized "end of fil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Buildings And Structures In Altona, Hamburg
A building, or edifice, is an enclosed structure with a roof and walls standing more or less permanently in one place, such as a house or factory (although there's also portable buildings). Buildings come in a variety of sizes, shapes, and functions, and have been adapted throughout history for a wide number of factors, from building materials available, to weather conditions, land prices, ground conditions, specific uses, monument, prestige, and aesthetic reasons. To better understand the term ''building'' compare the list of nonbuilding structures. Buildings serve several societal needs – primarily as shelter from weather, security, living space, privacy, to store belongings, and to comfortably live and work. A building as a shelter represents a physical division of the :Human habitats, human habitat (a place of comfort and safety) and the ''outside'' (a place that at times may be harsh and harmful). Ever since the first cave paintings, buildings have also become objects or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
LEPS
SPring-8 (an acronym of Super Photon Ring – 8 GeV) is a synchrotron radiation facility located in Sayo Town, Sayo District, Hyōgo Prefecture, Japan, which is the main facility of Harima Science Garden City. It was developed jointly by RIKEN and the Japan Atomic Energy Research Institute, and is owned and managed by RIKEN, and run under commission by the Japan Synchrotron Radiation Research Institute. The machine consists of a storage ring containing an 8 GeV electron beam. On its path around the storage ring, the beam passes through insertion devices to produce synchrotron radiation with energies ranging from soft X-rays (300 eV) up to hard X-rays (300 keV). The synchrotron radiation produced at SPring-8 is used for materials analysis and biochemical protein characterization by many Japanese manufacturers and universities. Together with the Advanced Photon Source at Argonne National Laboratory and the Cornell High Energy Synchrotron Source at Cornell University ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CLAS Detector
CEBAF Large Acceptance Spectrometer (CLAS) is a nuclear and particle physics detector located in the experimental Hall B at Jefferson Laboratory in Newport News, Virginia, United States. It is used to study the properties of the nuclear matter by the collaboration of over 200 physicists (CLAS Collaboration) from many countries all around the world. The 0.5 to 12.0 GeV electron beam from the accelerator of Jefferson Laboratory is brought into "Hall B", the experimental hall that houses the CLAS system. Electrons or photons in the incoming beam collide with the nuclei of atoms in the physics "target" located at the center of CLAS. These collisions generally produce new particles, often after the target nucleons (protons and neutrons) are briefly excited to heavier-mass versions of the familiar protons and neutrons. A whole variety of intermediate-mass short-lived particles called "mesons" can be created. Scattered electron as well as the longer-lived produced particles travel through t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synchrotron Radiation
Synchrotron radiation (also known as magnetobremsstrahlung radiation) is the electromagnetic radiation emitted when relativistic charged particles are subject to an acceleration perpendicular to their velocity (). It is produced artificially in some types of particle accelerators, or naturally by fast electrons moving through magnetic fields. The radiation produced in this way has a characteristic polarization and the frequencies generated can range over a large portion of the electromagnetic spectrum. Synchrotron radiation is similar to bremsstrahlung radiation, which is emitted by a charged particle when the acceleration is parallel to the direction of motion. The general term for radiation emitted by particles in a magnetic field is ''gyromagnetic radiation'', for which synchrotron radiation is the ultra-relativistic special case. Radiation emitted by charged particles moving non-relativistically in a magnetic field is called cyclotron emission. For particles in the mildly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Compton Scattering
Compton scattering, discovered by Arthur Holly Compton, is the scattering of a high frequency photon after an interaction with a charged particle, usually an electron. If it results in a decrease in energy (increase in wavelength) of the photon (which may be an X-ray or gamma ray photon), it is called the Compton effect. Part of the energy of the photon is transferred to the recoiling electron. Inverse Compton scattering occurs when a charged particle transfers part of its energy to a photon. Introduction Compton scattering is an example of elastic scattering of light by a free charged particle, where the wavelength of the scattered light is different from that of the incident radiation. In Compton's original experiment (see Fig. 1), the energy of the X ray photon (≈17 keV) was significantly larger than the binding energy of the atomic electron, so the electrons could be treated as being free after scattering. The amount by which the light's wavelength changes is called the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrogen
Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic, and highly combustible. Hydrogen is the most abundant chemical substance in the universe, constituting roughly 75% of all normal matter.However, most of the universe's mass is not in the form of baryons or chemical elements. See dark matter and dark energy. Stars such as the Sun are mainly composed of hydrogen in the plasma state. Most of the hydrogen on Earth exists in molecular forms such as water and organic compounds. For the most common isotope of hydrogen (symbol 1H) each atom has one proton, one electron, and no neutrons. In the early universe, the formation of protons, the nuclei of hydrogen, occurred during the first second after the Big Bang. The emergence of neutral hydrogen atoms throughout the universe occurred about 370,000 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tesla (unit)
The tesla (symbol: T) is the unit of magnetic flux density (also called magnetic B-field strength) in the International System of Units (SI). One tesla is equal to one weber per square metre. The unit was announced during the General Conference on Weights and Measures in 1960 and is named in honour of Serbian-American electrical and mechanical engineer Nikola Tesla, upon the proposal of the Slovenian electrical engineer France Avčin. Definition A particle, carrying a charge of one coulomb (C), and moving perpendicularly through a magnetic field of one tesla, at a speed of one metre per second (m/s), experiences a force with magnitude one newton (N), according to the Lorentz force law. That is, : \text = \dfrac. As an SI derived unit, the tesla can also be expressed in terms of other units. For example, a magnetic flux of 1 weber (Wb) through a surface of one square meter is equal to a magnetic flux density of 1 tesla.''The International System of Units (SI), 8th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PETRA
Petra ( ar, ٱلْبَتْرَاء, Al-Batrāʾ; grc, Πέτρα, "Rock", Nabataean Aramaic, Nabataean: ), originally known to its inhabitants as Raqmu or Raqēmō, is an historic and archaeological city in southern Jordan. It is adjacent to the mountain of Jebel al-Madhbah, Jabal Al-Madbah, in a Depression (geology), basin surrounded by mountains forming the eastern flank of the Arabah valley running from the Dead Sea to the Gulf of Aqaba. The area around Petra has been inhabited from as early as 7000 BC, and the Nabataeans might have settled in what would become the capital city of Nabataean Kingdom, their kingdom as early as the 4th century BC. Archaeological work has only discovered evidence of Nabataean presence dating back to the second century BC, by which time Petra had become their capital. The Nabataeans were nomadic Arabs who invested in Petra's proximity to the incense trade routes by establishing it as a major regional trading hub. The trading business gained ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Particle Detector
In experimental and applied particle physics, nuclear physics, and nuclear engineering, a particle detector, also known as a radiation detector, is a device used to detect, track, and/or identify ionizing particles, such as those produced by nuclear decay, cosmic radiation, or reactions in a particle accelerator. Detectors can measure the particle energy and other attributes such as momentum, spin, charge, particle type, in addition to merely registering the presence of the particle. Examples and types Many of the detectors invented and used so far are ionization detectors (of which gaseous ionization detectors and semiconductor detectors are most typical) and scintillation detectors; but other, completely different principles have also been applied, like Čerenkov light and transition radiation. Historical examples *Bubble chamber * Wilson cloud chamber (diffusion chamber) * Photographic plate ;Detectors for radiation protection The following types of particle detector ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
