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Walter H. Barkas
Walter Henry Barkas (2 September 1912 – 28 March 1969) was professor of physics at the University of California, Riverside beginning in 1965. He specialized in the use of nuclear emulsions, i.e., photographic plates having a thick sensitive layer, for purposes of Particle physics. Together with his collaborators, he discovered the difference in range between positive and negative mesons of the same initial energy, and he ascribed this effect to the difference in stopping power between positively and negatively charged particles. Hence, this difference is called ''Barkas effect'' or ''Barkas-Andersen effect'', see Bethe formula. Barkas was a visiting scholar at the Institute for Advanced Study in 1938-40. In 1941 he was elected as Fellow of the American Physical Society. Biography He was born on 2 September 1912 in Portland, Oregon to Leander Henrikson Barkas and Ester Emilia Gustafsson. He became a professor of physics at the University of California, Riverside in 1965. He died ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
University Of California, Riverside
The University of California, Riverside (UCR or UC Riverside) is a public university, public Land-grant university, land-grant research university in Riverside, California, United States. It is one of the ten campuses of the University of California system. The main campus sits on in a suburban district of Riverside with a branch campus of in Palm Desert, California, Palm Desert. In 1907, the predecessor to UCR was founded as the UC Citrus Experiment Station, which conducted research in biological pest control and the use of plant hormone, growth regulators. UCR's undergraduate UCR College of Humanities, Arts, and Social Sciences, College of Letters and Science opened in 1954. The Regents of the University of California declared UCR a general campus of the system in 1959, and graduate students were admitted in 1961. To accommodate an enrollment of 21,000 students by 2015, more than $730 million has been invested in new construction projects since 1999. UCR plans to have ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Physical Society
The American Physical Society (APS) is a not-for-profit membership organization of professionals in physics and related disciplines, comprising nearly fifty divisions, sections, and other units. Its mission is the advancement and diffusion of knowledge of physics. It publishes more than a dozen scientific journals, including the prestigious '' Physical Review'' and ''Physical Review Letters'', and organizes more than twenty science meetings each year. It is a member society of the American Institute of Physics. Since January 2021, it is led by chief executive officer Jonathan Bagger. History The American Physical Society was founded on May 20, 1899, when thirty-six physicists gathered at Columbia University for that purpose. They proclaimed the mission of the new Society to be "to advance and diffuse the knowledge of physics", and in one way or another the APS has been at that task ever since. In the early years, virtually the sole activity of the APS was to hold scientific m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Institute For Advanced Study Visiting Scholars
An institute is an organizational body created for a certain purpose. They are often research organisations (research institutes) created to do research on specific topics, or can also be a professional body. In some countries, institutes can be part of a university or other institutions of higher education, either as a group of departments or an autonomous educational institution without a traditional university status such as a "university institute", or institute of technology. In some countries, such as South Korea and India, private schools are sometimes referred to as institutes; also, in Spain, secondary schools are referred to as institutes. Historically, in some countries, institutes were educational units imparting vocational training and often incorporating libraries, also known as mechanics' institutes. The word "institute" comes from the Latin word ''institutum'' ("facility" or "habit"), in turn derived from ''instituere'' ("build", "create", "raise" or "educ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1969 Deaths
1969 (Roman numerals, MCMLXIX) was a common year starting on Wednesday of the Gregorian calendar, the 1969th year of the Common Era (CE) and ''Anno Domini'' (AD) designations, the 969th year of the 2nd millennium, the 69th year of the 20th century, and the 10th and last year of the 1960s decade. Events January * January 4 – The Government of Spain hands over Ifni to Morocco. * January 5 – Ariana Afghan Airlines Flight 701 crashes into a house on its approach to London's Gatwick Airport, killing 50 of the 62 people on board and two of the home's occupants. * January 14 – USS Enterprise fire, An explosion aboard the aircraft carrier USS Enterprise (CVN-65), USS ''Enterprise'' near Hawaii kills 28 and injures 314. * January 16 – First successful docking of two crewed spacecraft in orbit and the first transfer of crew from one space vehicle to another (by a space walk) between Soviet craft Soyuz 5 and Soyuz 4. * January 18 – Failure of Soyuz 5's service module to separ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1912 Births
This year is notable for Sinking of the Titanic, the sinking of the ''Titanic'', which occurred on April 15. In Albania, this leap year runs with only 353 days as the country achieved switching from the Julian to Gregorian Calendar by skipping 13 days. Friday, 30 November ''(Julian Calendar)'' immediately turned Saturday, 14 December 1912 ''(in the Gregorian Calendar)''. Events January * January 1 – The Republic of China (1912–49), Republic of China is established. * January 5 – The Prague Conference (6th All-Russian Conference of the Russian Social Democratic Labour Party) opens. * January 6 ** German Geophysics, geophysicist Alfred Wegener first presents his theory of continental drift. ** New Mexico becomes the 47th U.S. state. * January 8 – The African National Congress is founded as the South African Native National Congress, at the Waaihoek Wesleyan Church in Bloemfontein, to promote improved rights for Black people, black South Africans, with Joh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Riverside, California
Riverside is a city in and the county seat of Riverside County, California, United States. It is named for its location beside the Santa Ana River. As of the 2020 census, the city has a population of 314,998. It is the most populous city in the Inland Empire and Riverside County, the List of largest California cities by population, 12th-most populous city in California, and the List of United States cities by population, 61st-most populous city in the United States. Alongside San Bernardino, Riverside is a principal city in the nation's 13th-largest metropolitan statistical area; the Riverside–San Bernardino–Ontario had 4.6 million residents in 2020. Riverside is about southeast of downtown Los Angeles and is also part of the Greater Los Angeles area. Riverside was founded in the early 1870s. It is the birthplace of the California citrus production, citrus industry and home of the The Mission Inn Hotel & Spa, Mission Inn, the nation's largest Mission Revival Style architec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Portland, Oregon
Portland ( ) is the List of cities in Oregon, most populous city in the U.S. state of Oregon, located in the Pacific Northwest region. Situated close to northwest Oregon at the confluence of the Willamette River, Willamette and Columbia River, Columbia rivers, it is the county seat of Multnomah County, Oregon, Multnomah County, Oregon's most populous county. Portland's population was 652,503, making it the List of United States cities by population, 28th most populous city in the United States, the sixth most populous on the West Coast of the United States, West Coast, and the third most populous in the Pacific Northwest after Seattle and Vancouver. Approximately 2.5 million people live in the Portland metropolitan area, Oregon, Portland metropolitan area, making it the List of metropolitan statistical areas, 26th most populous in the United States. Almost half of Oregon's population resides within the Portland metro area. Named after Portland, Maine, which is itself named aft ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Institute For Advanced Study
The Institute for Advanced Study (IAS) is an independent center for theoretical research and intellectual inquiry located in Princeton, New Jersey. It has served as the academic home of internationally preeminent scholars, including Albert Einstein, J. Robert Oppenheimer, Emmy Noether, Hermann Weyl, John von Neumann, Michael Walzer, Clifford Geertz and Kurt Gödel, many of whom had emigrated from Europe to the United States. It was founded in 1930 by American educator Abraham Flexner, together with philanthropists Louis Bamberger and Caroline Bamberger Fuld. Despite collaborative ties and neighboring geographic location, the institute, being independent, has "no formal links" with Princeton University. The institute does not charge tuition or fees. Flexner's guiding principle in founding the institute was the pursuit of knowledge for its own sake.Jogalekar. The faculty have no classes to teach. There are no degree programs or experimental facilities at the institute. Research ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nuclear Emulsion
A nuclear emulsion plate is a type of particle detector first used in nuclear and particle physics experiments in the early decades of the 20th century. https://cds.cern.ch/record/1728791/files/vol6-issue5-p083-e.pdf''The Study of Elementary Particles by the Photographic Method'', C.F.Powell, P.H.Fowler, D.H.Perkins: Pergamon Press, New York, 1959.Walter H. Barkas, ''Nuclear Research Emulsions I. Techniques and Theory'', in ''Pure and Applied Physics: A Series of Monographs and Textbooks, Vol. 15'', Academic Press, New York and London, 1963. http://becquerel.jinr.ru/text/books/Barkas_NUCL_RES_EMULSIONS.pdf It is a modified form of photographic plate that can be used to record and investigate fast charged particles like alpha-particles, nucleons, leptons or mesons. After exposing and developing the emulsion, single particle tracks can be observed and measured using a microscope. Description The nuclear emulsion plate is a modified form of photographic plate, coated with a thick ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bethe Formula
The Bethe formula or Bethe–Bloch formula describes the mean energy loss per distance travelled of swift charged particles (protons, alpha particles, atomic ions) traversing matter (or alternatively the stopping power of the material). For electrons the energy loss is slightly different due to their small mass (requiring relativistic corrections) and their indistinguishability, and since they suffer much larger losses by Bremsstrahlung, terms must be added to account for this. Fast charged particles moving through matter interact with the electrons of atoms in the material. The interaction excites or ionizes the atoms, leading to an energy loss of the traveling particle. The non-relativistic version was found by Hans Bethe in 1930; the relativistic version (shown below) was found by him in 1932.Sigmund, Peter ''Particle Penetration and Radiation Effects. Springer Series in Solid State Sciences, 151.'' Berlin Heidelberg: Springer-Verlag. (2006) The most probable energy loss diff ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stopping Power (particle Radiation)
In nuclear and materials physics, stopping power is the retarding force acting on charged particles, typically alpha and beta particles, due to interaction with matter, resulting in loss of particle kinetic energy. Stopping power is also interpreted as the rate at which a material absorbs the kinetic energy of a charged particle. Its application is important in a wide range of thermodynamic areas such as radiation protection, ion implantation and nuclear medicine.ICRU Report 73: Stopping of Ions heavier than Helium, Journal of the ICRU, 5 No. 1 (2005), Oxford Univ. Press Definition and Bragg curve Both charged and uncharged particles lose energy while passing through matter. Positive ions are considered in most cases below. The stopping power depends on the type and energy of the radiation and on the properties of the material it passes. Since the production of an ion pair (usually a positive ion and a (negative) electron) requires a fixed amount of energy (for example, 33 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
