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Cyclotrons
A cyclotron is a type of particle accelerator invented by Ernest Lawrence in 1929–1930 at the University of California, Berkeley, and patented in 1932. Lawrence, Ernest O. ''Method and apparatus for the acceleration of ions'', filed: January 26, 1932, granted: February 20, 1934 A cyclotron accelerates charged particles outwards from the center of a flat cylindrical vacuum chamber along a spiral path. The particles are held to a spiral trajectory by a static magnetic field and accelerated by a rapidly varying electric field. Lawrence was awarded the 1939 Nobel Prize in Physics for this invention. The cyclotron was the first "cyclical" accelerator. The primary accelerators before the development of the cyclotron were electrostatic accelerators, such as the Cockcroft–Walton generator and the Van de Graaff generator. In these accelerators, particles would cross an accelerating electric field only once. Thus, the energy gained by the particles was limited by the maximum elect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Particle Accelerator
A particle accelerator is a machine that uses electromagnetic fields to propel electric charge, charged particles to very high speeds and energies to contain them in well-defined particle beam, beams. Small accelerators are used for fundamental research in particle physics. 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 oncology, oncological purposes, Isotopes in medicine, radioisotope production for medical diagnostics, Ion implantation, ion implanters for the manufacturing of Semiconductor, semiconductors, and Accelerator mass spectrometry, accelerator mass spectrometers for measurements of rare isotopes such as radiocarbon. Large accelerators include the Relativistic Heavy Ion Collider at Brookhaven National Laboratory in New York, and the largest accelerator, the Large Hadron Collider near Geneva, Switzerland, operated b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ernest Lawrence
Ernest Orlando Lawrence (August 8, 1901 – August 27, 1958) was an American accelerator physicist who received the Nobel Prize in Physics in 1939 for his invention of the cyclotron. He is known for his work on uranium-isotope separation for the Manhattan Project, as well as for founding the Lawrence Berkeley National Laboratory and the Lawrence Livermore National Laboratory. A graduate of the University of South Dakota and University of Minnesota, Lawrence obtained a PhD in physics at Yale in 1925. In 1928, he was hired as an associate professor of physics at the University of California, Berkeley, becoming the youngest full professor there two years later. In its library one evening, Lawrence was intrigued by a diagram of an accelerator that produced high-energy particles. He contemplated how it could be made compact, and came up with an idea for a circular accelerating chamber between the poles of an electromagnet. The result was the first cyclotron. Lawrence went on t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Particle Therapy
Particle therapy is a form of external beam radiotherapy using beams of energetic neutrons, protons, or other heavier positive ions for cancer treatment. The most common type of particle therapy as of August 2021 is proton therapy. In contrast to X-rays (photon beams) used in older radiotherapy, particle beams exhibit a Bragg peak in energy loss through the body, delivering their maximum radiation dose at or near the tumor and minimizing damage to surrounding normal tissues. Particle therapy is also referred to more technically as hadron therapy, excluding photon and electron therapy. Neutron capture therapy, which depends on a secondary nuclear reaction, is also not considered here. Muon therapy, a rare type of particle therapy not within the categories above, has also been studied theoretically; however, muons are still most commonly used for imaging, rather than therapy. Method Particle therapy works by aiming energetic ionizing particles at the target tumor. These par ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arc Converter
The arc converter, sometimes called the arc transmitter, or Poulsen arc after Danish engineer Valdemar Poulsen who invented it in 1903, was a variety of spark transmitter used in early wireless telegraphy. The arc converter used an electric arc to convert direct current electricity into radio frequency alternating current. It was used as a radio transmitter from 1903 until the 1920s when it was replaced by vacuum tube transmitters. One of the first transmitters that could generate continuous sinusoidal waves, it was one of the first technologies used to transmit sound (amplitude modulation) by radio. It is on the list of IEEE Milestones as a historic achievement in electrical engineering. History Elihu Thomson discovered that a carbon arc shunted with a series tuned circuit would "sing". This "singing arc" was probably limited to audio frequencies. Bureau of Standards credits William Duddell with the shunt resonant circuit around 1900. The English engineer William Duddell di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Addison Wesley
Addison–Wesley is an American publisher of textbooks and computer literature. It is an imprint of Pearson plc, a global publishing and education company. In addition to publishing books, Addison–Wesley also distributes its technical titles through the O'Reilly Online Learning e-reference service. Addison–Wesley's majority of sales derive from the United States (55%) and Europe (22%). The Addison–Wesley Professional Imprint produces content including books, eBooks, and video for the professional IT worker including developers, programmers, managers, system administrators. Classic titles include '' The Art of Computer Programming'', '' The C++ Programming Language'', '' The Mythical Man-Month'', and '' Design Patterns''. History Lew Addison Cummings and Melbourne Wesley Cummings founded Addison–Wesley in 1942, with the first book published by Addison–Wesley being Massachusetts Institute of Technology professor Francis Weston Sears' ''Mechanics''. Its first comput ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Science (journal)
''Science'' is the peer review, peer-reviewed academic journal of the American Association for the Advancement of Science (AAAS) and one of the world's top academic journals. It was first published in 1880, is currently circulated weekly and has a subscriber base of around 130,000. Because institutional subscriptions and online access serve a larger audience, its estimated readership is over 400,000 people. ''Science'' is based in Washington, D.C., United States, with a second office in Cambridge, UK. Contents The major focus of the journal is publishing important original scientific research and research reviews, but ''Science'' also publishes science-related news, opinions on science policy and other matters of interest to scientists and others who are concerned with the wide implications of science and technology. Unlike most scientific journals, which focus on a specific field, ''Science'' and its rival ''Nature (journal), Nature'' cover the full range of List of academ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
UC Berkeley
The University of California, Berkeley (UC Berkeley, Berkeley, Cal, or California), is a public land-grant research university in Berkeley, California, United States. Founded in 1868 and named after the Anglo-Irish philosopher George Berkeley, it is the state's first land-grant university and is the founding campus of the University of California system. Berkeley has an enrollment of more than 45,000 students. The university is organized around fifteen schools of study on the same campus, including the College of Chemistry, the College of Engineering, College of Letters and Science, and the Haas School of Business. It is classified among "R1: Doctoral Universities – Very high research activity". Lawrence Berkeley National Laboratory was originally founded as part of the university. Berkeley was a founding member of the Association of American Universities and was one of the original eight " Public Ivy" schools. In 2021, the federal funding for campus research and dev ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bancroft Library
The Bancroft Library is the primary special-collections library of the University of California, Berkeley. It was acquired from its founder, Hubert Howe Bancroft, in 1905, with the proviso that it retain the name Bancroft Library in perpetuity. The collection at that time consisted of 50,000 volumes of materials on the history of California and western North America. It is now the largest such collection in the world. The library's current building, the Doe Annex, is in the center of the university's main campus, and was completed in 1950. Inception The Bancroft Library's inception dates back to 1859, when William H. Knight, who was then in Bancroft's service as editor of statistical works relative to the Pacific coast, was requested to clear the shelves around Bancroft's desk to receive every book in the store having reference to this country. Looking through his stock he was agreeably surprised to find some 50 or 75 volumes. There was no fixed purpose at this time to collect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rolf Widerøe
Rolf Widerøe (11 July 1902 – 11 October 1996) was a Norwegian accelerator physicist who was the originator of many particle acceleration concepts, including the ''resonance accelerator'' and the betatron accelerator. Early life Widerøe was born in Kristiania (now Oslo) in 1902 as a son of the mercantile agent Theodor Widerøe (1868–1947) and Carla Johanne Launer (1875–1971). He was a brother of the aviator and entrepreneur Viggo Widerøe who became the founder of the Norwegian airline Widerøe. After his A-level exams ( Examen artium) in the summer of 1920 at the Halling School in Oslo, Widerøe left for the university of Karlsruhe, Germany, to study electrical engineering. Betatron accelerator concept There he conceived the concept of electromagnetic induction to accelerate electrons, which became the basis of what would be known as betatron. This idea was to use a vortex field surrounding a magnetic field for cyclic acceleration of electrons in a tube. Return to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Betatron
A betatron is a type of cyclic particle accelerator for electrons. It consists of a torus-shaped vacuum chamber with an electron source. Circling the torus is an iron transformer core with a wire winding around it. The device functions similarly to a transformer, with the electrons in the torus-shaped vacuum chamber as its secondary coil. An alternating current in the primary coils accelerates electrons in the vacuum around a circular path. The betatron was the first machine capable of producing electron beams at energies higher than could be achieved with a simple electron gun, and the first circular accelerator in which particles orbited at a constant radius. The concept of the betatron had been proposed as early as 1922 by Joseph Slepian. Through the 1920s and 30s a number of theoretical problems related to the device were considered by scientists including Rolf Wideroe, Ernest Walton, and Max Steenbeck. The first working betatron was constructed by Donald Kerst ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Linear Accelerator
A linear particle accelerator (often shortened to linac) is a type of particle accelerator that accelerates charged subatomic particles or ions to a high speed by subjecting them to a series of oscillating electric potentials along a linear beamline. The principles for such machines were proposed by Gustav Ising in 1924, while the first machine that worked was constructed by Rolf Widerøe in 1928 at the RWTH Aachen University. Linacs have many applications: they generate X-rays and high energy electrons for medicinal purposes in radiation therapy, serve as particle injectors for higher-energy accelerators, and are used directly to achieve the highest kinetic energy for light particles (electrons and positrons) for particle physics. The design of a linac depends on the type of particle that is being accelerated: electrons, protons or ions. Linacs range in size from a cathode-ray tube (which is a type of linac) to the linac at the SLAC National Accelerator Laboratory in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
