Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Database Design for Superconducting Magnets CERN Summer Student 2006 Tae-Joon Cho (Cambridge) Under supervision of Dr. Walter Scandale (CERN) Emanuele Laface (CERN) 16 August 2006 Database design for superconducting magnets Contents • • • • • • • Magnets and Magnetic Field B Superconductors Parameters Database survey and Collaborations Conclusions Bibliography (History) Development of Superconductivity Database design for superconducting magnets Magnets & Magnetic Field B • A magnet is an object that has a magnetic field. – Permanent magnets (Permagnets) & Electromagnets. e.g. Dipoles, Earth, Solenoids etc. • A magnetic field is that part of the electromagnetic field that exists when there is a changing electric field. Database design for superconducting magnets ? Superconductors I • • Superconductivity is a phenomenon occurring in certain materials at extremely low temperatures (~ a few K), characterized by exactly zero electrical resistance and the exclusion of the interior magnetic field (the Meissner effect) Superconductivity lim0(normal conductivity) – Superconductivity is a quantum mechanical phenomenon • Meissner effect Faraday’s / Lenz’s Law • Applications – • MRI, Particle Accelerators, etc. A comparison of Magnetic Field Strengths – – – – • <Magnetic Levitation above a Superconductor> Dipole BD : T ~ mT Earth’s BE : 30T ~ 60T ATLAS BATLAS : ~ 2T CMS BCMS : ~ 4T 103 ~ 105! A comparison of Typical Currents – Laptop : A ~ mA – A voltage source 220V, a resistance 220k 1mA mag(B) ~ 2T, I ~ 10,000,000A P ~ 1016kW – LHC requires ~ 12000A http://www.cartoonstock.com Database design for superconducting magnets Superconductors II Fie ld Jc Niobium Titanium (NbTi) (te sl a) c Bc2 Current density (kA.mm-2) T r pe em ) (K e r at u NbTi is a ductile Alloy Superconductivity below the surface Upper Bc First detailedcritical study in 1961field (John K.Hulm and Richard D.Blaugher) from Critical temperature Westinghouse Research Laboratories in c Pittsburgh, Pennsylvania) Critical current density Jc(Bc,c) Database design for superconducting magnets Superconductors III • Niobium-Titanium (NbTi) – Detailed study in 1961 – Critical temperature ~ 9K at 0T • Niobium-Tin (Nb3Sn) – Detailed study in 1954 – Critical temperature ~ 18K at 0T – Brittle Ductile Filaments x Coolant (liquid He ~ 4K) Higher critical field B Database design for superconducting magnets Parameters • • • • • • Critical temperature c Upper critical field Bc Critical current density Jc (Bc, c) Ductility Phase transitions Mechanical/Physical/Chemical properties More than 100 parameters Database design for superconducting magnets Database Survey http://sdb.web.cern.ch/sdb/ 8 Database design for superconducting magnets Collaborations • LHC at CERN • Tevatron at FermiLab • HERA (Hadron-Electron Ring Accelerator) in Hamburg, Germany • FAIR at GSI in Frankfurt, Germany • ITER (International Thermonuclear Experimental Reactor) in France • J-PARC (Japan Proton Accelerator Research Complex) at KEK in Japan • KEKB (Electron-positron colliding-beam accelerator) in Tsukuba Campus at KEK in Japan • ILC (International Linear Collider project) at KEK in Japan 9 Database design for superconducting magnets Conclusions • • • • • • • Increasing demand on superconductors More theoretical & experimental developments R&D on Permanent magets Recognition of main parameters Inter-relations of those parameters Collaborations User friendly Database (Oracle SQL) Database design for superconducting magnets Thank you for your attention! ? Database design for superconducting magnets Bibliography • Superconducting Magnets – Chapter 12 & 13 – Martin N. Wilson (Oxford University Press) • Practical Low-Temperature Superconductors for Electromagnets – A. Devred (CERN Report 2004) • Superconducting magnet technology for particle accelerators and detectors – T. Taylor (CERN Summer Student Lecture, 14 July 2006) • Wikipedia (http://www.wikipedia.org/) http://sdb.web.cern.ch/sdb/ History Development of Superconductivity In 1911, the group led by Heike Kammerling-Onnes (1853 1926, Netherlands) in a laboratory of Leiden University discovered superconductivity for the first time. • In 1933, Walter Meissner (1882 1974, Germany) and Robert Ochsenfeld (1901 1993, Germany) discovered total expulsion of the external magnetic fieldsstarted from superconductors In 1908, Heikethe Kammerling-Onnes (18531926, Netherlands) his Meissner / Meissner-Ochsenfeld careereffect by building liquefiers and was effect. the first to produce liquid helium (TB ~ 4.2K) used later London to investigate electrical properties ofand metals at London low • In 1935, Fritz Wolfgang (1900the 1954, Germany-USA) Heinz (1907 temperature. In 1911, one of his students, Gilles Holst, observed that the 1970, Germany) showed that the Meissner effect was a consequence of electromagnetic free of aofmercury wire completely at Theory. a temperature slightly energy resistance minimisation superconducting currentvanished London below 4.2K. Kammerling-Onnes called it the superconducting state. • In 1941, Lev Davidovich Landau (1908the 1968, addressed his theory of second-order (Kammerling-Onnes was awared 1913 USSR) Nobel Prize in Physics ‘for his phase transitions with Schrodingerlike equation successful to describe investigations onathe properties of matter at low temperatures which led to the the macroscopic properties of superconductors. production of liquid helium.’) • In 1950, and Vitaly Lazarevich 2006, USSR) earned the phenomenological Landau’s theory to explainGinzburg why liquid(1916 helium was super-fluid him the 1962 Ginzburg-Landau Theory. Nobel Prize for Physics. • In 1957, John 1991, USA), Cooper , USA) and It had Bardeen been noted(1908 experimentally that if Leon liquid Neil helium at these(1930 low temperatures wasJohn Robert Schrieffer then ,USA) published microscopic theory of superconductivity, placed in a(1931 beaker, it climbed outthe of the beaker until the level outside was equal the concept oftoCooper pairs was introduced. that inside. Similarly liquid helium would climb into the beaker if the level outside that in the beaker. Landau devised a theoryshowed to explain behaviour • In 1957, exceeded Alexei Alexeyevich Abrikosov (1928 , USSR) thatsuch Ginzburg-Landau In 1972, the microscopic theory of superconductors earned its authors, Bardeen, Cooper and Schrieffer the which was in 1941. It predicted ainto newthe phenomenon, namely a temperature theory predicts the published division of superconductors two categories now referred to as Nobel Prize in Physics ‘for their jointly developed theory of superconductivity, usually called the BCSwave described a "second sound", and three years later experimental evidence Type I and Type II the theory of the mixed state of type-II superconductors by analogy with theory’. produced in Moscow themagnetic existencevortices of "second sound". was introduced. superfluidity in helium and theconfirmed concept of / fluxoids <Landau> • In 2003, Abrikosov and Ginzburg alongside Anthony James Legget (1938 , UK) were awarded Nobel Prize for pioneering contributions to the theory of superconductors and superfluids. More developments and <Heiketheoretical Kamerlingh Onnes> <The First Measure of Superconductivity> <John Bardeen> to come! <First Temperature vs. Resistance Graph for a High Tc Superconductor> <Leon Neil Cooper> <John Robert Schrieffer>