Jews or Jewish people are an ethnoreligious group and a nation, originating from the Israelites and Hebrews of historical Israel and Judah. Jewish ethnicity and religion are interrelated, as Judaism is the traditional faith of the Jewish people, while its observance varies from strict observance to complete nonobservance. Jews originated as an ethnic and religious group in the Middle East during the second millennium BCE, in the part of the Levant known as the Land of Israel; the Merneptah Stele appears to confirm the existence of a people of Israel somewhere in Canaan as far back as the 13th century BCE. The Israelites, as an outgrowth of the Canaanite population, consolidated their hold with the emergence of the kingdoms of Israel and Judah; some consider that these Canaanite sedentary Israelites melded with incoming nomadic groups known as'Hebrews'. Though few sources mention the exilic periods in detail, the experience of diaspora life, from the Ancient Egyptian rule over the Levant, to Assyrian captivity and exile, to Babylonian captivity and exile, to Seleucid Imperial rule, to the Roman occupation and exile, the historical relations between Jews and their homeland thereafter, became a major feature of Jewish history and memory.
Prior to World War II, the worldwide Jewish population reached a peak of 16.7 million, representing around 0.7% of the world population at that time. 6 million Jews were systematically murdered during the Holocaust. Since the population has risen again, as of 2016 was estimated at 14.4 million by the Berman Jewish DataBank, less than 0.2% of the total world population. The modern State of Israel is the only country, it defines itself as a Jewish and democratic state in the Basic Laws, Human Dignity and Liberty in particular, based on the Declaration of Independence. Israel's Law of Return grants the right of citizenship to Jews who have expressed their desire to settle in Israel. Despite their small percentage of the world's population, Jews have influenced and contributed to human progress in many fields, both and in modern times, including philosophy, literature, business, fine arts and architecture, music and cinema, science and technology, as well as religion. Jews have played a significant role in the development of Western Civilization.
The English word "Jew" continues Iewe. These terms derive from Old French giu, earlier juieu, which through elision had dropped the letter "d" from the Medieval Latin Iudaeus, like the New Testament Greek term Ioudaios, meant both "Jew" and "Judean" / "of Judea"; the Greek term was a loan from Aramaic Y'hūdāi, corresponding to Hebrew יְהוּדִי Yehudi the term for a member of the tribe of Judah or the people of the kingdom of Judah. According to the Hebrew Bible, the name of both the tribe and kingdom derive from Judah, the fourth son of Jacob. Genesis 29:35 and 49:8 connect the name "Judah" with the verb yada, meaning "praise", but scholars agree that the name of both the patriarch and the kingdom instead have a geographic origin—possibly referring to the gorges and ravines of the region; the Hebrew word for "Jew" is יְהוּדִי Yehudi, with the plural יְהוּדִים Yehudim. Endonyms in other Jewish languages include the Yiddish ייִד Yid; the etymological equivalent is in use in other languages, e.g. يَهُودِيّ yahūdī, al-yahūd, in Arabic, "Jude" in German, "judeu" in Portuguese, "Juif" /"Juive" in French, "jøde" in Danish and Norwegian, "judío/a" in Spanish, "jood" in Dutch, "żyd" in Polish etc. but derivations of the word "Hebrew" are in use to describe a Jew, e.g. in Italian, in Persian and Russian.
The German word "Jude" is pronounced, the corresponding adjective "jüdisch" is the origin of the word "Yiddish". According to The American Heritage Dictionary of the English Language, fourth edition, It is recognized that the attributive use of the noun Jew, in phrases such as Jew lawyer or Jew ethics, is both vulgar and offensive. In such contexts Jewish is the only acceptable possibility; some people, have become so wary of this construction that they have extended the stigma to any use of Jew as a noun, a practice that carries risks of its own. In a sentence such as There are now several Jews on the council, unobjectionable, the substitution of a circumlocution like Jewish people or persons of Jewish background may in itself cause offense for seeming to imply that Jew has a negative connotation when used as a noun. Judaism shares some of the characteristics of a nation, an ethnicity, a religion, a culture, making the definition of, a Jew vary depending on whether a religious or national approach to identity is used.
In modern secular usage Jews include three groups: people who were born to a Jewish family regardless of whether or not they follow the religion, those who have some Jewish ancestral background or lineage, people without any Jewish ancestral background or lineage who have formally converted to Judaism and therefore are followers of the religion. Historical definitions of Jewish identity have traditionally been based on halakhic definitions of matrilineal descent, halakhic conversions; these definitions of, a Jew date back to the codification of the Oral
Germany the Federal Republic of Germany, is a country in Central and Western Europe, lying between the Baltic and North Seas to the north, the Alps to the south. It borders Denmark to the north and the Czech Republic to the east and Switzerland to the south, France to the southwest, Luxembourg and the Netherlands to the west. Germany includes 16 constituent states, covers an area of 357,386 square kilometres, has a temperate seasonal climate. With 83 million inhabitants, it is the second most populous state of Europe after Russia, the most populous state lying in Europe, as well as the most populous member state of the European Union. Germany is a decentralized country, its capital and largest metropolis is Berlin, while Frankfurt serves as its financial capital and has the country's busiest airport. Germany's largest urban area is the Ruhr, with its main centres of Essen; the country's other major cities are Hamburg, Cologne, Stuttgart, Düsseldorf, Dresden, Bremen and Nuremberg. Various Germanic tribes have inhabited the northern parts of modern Germany since classical antiquity.
A region named Germania was documented before 100 AD. During the Migration Period, the Germanic tribes expanded southward. Beginning in the 10th century, German territories formed a central part of the Holy Roman Empire. During the 16th century, northern German regions became the centre of the Protestant Reformation. After the collapse of the Holy Roman Empire, the German Confederation was formed in 1815; the German revolutions of 1848–49 resulted in the Frankfurt Parliament establishing major democratic rights. In 1871, Germany became a nation state when most of the German states unified into the Prussian-dominated German Empire. After World War I and the revolution of 1918–19, the Empire was replaced by the parliamentary Weimar Republic; the Nazi seizure of power in 1933 led to the establishment of a dictatorship, the annexation of Austria, World War II, the Holocaust. After the end of World War II in Europe and a period of Allied occupation, Austria was re-established as an independent country and two new German states were founded: West Germany, formed from the American and French occupation zones, East Germany, formed from the Soviet occupation zone.
Following the Revolutions of 1989 that ended communist rule in Central and Eastern Europe, the country was reunified on 3 October 1990. Today, the sovereign state of Germany is a federal parliamentary republic led by a chancellor, it is a great power with a strong economy. As a global leader in several industrial and technological sectors, it is both the world's third-largest exporter and importer of goods; as a developed country with a high standard of living, it upholds a social security and universal health care system, environmental protection, a tuition-free university education. The Federal Republic of Germany was a founding member of the European Economic Community in 1957 and the European Union in 1993, it is part of the Schengen Area and became a co-founder of the Eurozone in 1999. Germany is a member of the United Nations, NATO, the G7, the G20, the OECD. Known for its rich cultural history, Germany has been continuously the home of influential and successful artists, musicians, film people, entrepreneurs, scientists and inventors.
Germany has a large number of World Heritage sites and is among the top tourism destinations in the world. The English word Germany derives from the Latin Germania, which came into use after Julius Caesar adopted it for the peoples east of the Rhine; the German term Deutschland diutisciu land is derived from deutsch, descended from Old High German diutisc "popular" used to distinguish the language of the common people from Latin and its Romance descendants. This in turn descends from Proto-Germanic *þiudiskaz "popular", derived from *þeudō, descended from Proto-Indo-European *tewtéh₂- "people", from which the word Teutons originates; the discovery of the Mauer 1 mandible shows that ancient humans were present in Germany at least 600,000 years ago. The oldest complete hunting weapons found anywhere in the world were discovered in a coal mine in Schöningen between 1994 and 1998 where eight 380,000-year-old wooden javelins of 1.82 to 2.25 m length were unearthed. The Neander Valley was the location where the first non-modern human fossil was discovered.
The Neanderthal 1 fossils are known to be 40,000 years old. Evidence of modern humans dated, has been found in caves in the Swabian Jura near Ulm; the finds included 42,000-year-old bird bone and mammoth ivory flutes which are the oldest musical instruments found, the 40,000-year-old Ice Age Lion Man, the oldest uncontested figurative art discovered, the 35,000-year-old Venus of Hohle Fels, the oldest uncontested human figurative art discovered. The Nebra sky disk is a bronze artefact created during the European Bronze Age attributed to a site near Nebra, Saxony-Anhalt, it is part of UNESCO's Memory of the World Programme. The Germanic tribes are thought to date from the Pre-Roman Iron Age. From southern Scandinavia and north Germany, they expanded south and west from the 1st century BC, coming into contact with the Celtic tribes of Gaul as well
Max Planck Society
The Max Planck Society for the Advancement of Science is a formally independent non-governmental and non-profit association of German research institutes founded in 1911 as the Kaiser Wilhelm Society and renamed the Max Planck Society in 1948 in honor of its former president, theoretical physicist Max Planck. The society is funded by the federal and state governments of Germany. According to its primary goal, the Max Planck Society supports fundamental research in the natural and social sciences, the arts and humanities in its 84 Max Planck Institutes; the society has a total staff of 17,000 permanent employees, including 5,470 scientists, plus around 4,600 non-tenured scientists and guests. The society's budget for 2015 was about €1.7 billion. As of December 31, 2016, the Max Planck Society employed a total of 22,995 staff, of whom 14,036 were scientists, which represents nearly 61 percent of the total number of employees. 44.3% were female employees and 27% of all of the employees were foreign nationals.
The Max Planck Institutes focus on excellence in research. The Max Planck Society has a world-leading reputation as a science and technology research organization, with 33 Nobel Prizes awarded to their scientists, is regarded as one of the foremost basic research organizations in the world. In 2018, the Nature Publishing Index placed the Max Planck institutes third worldwide in terms of research published in Nature journals. In terms of total research volume, the Max Planck Society is only outranked by the Chinese Academy of Sciences, the Russian Academy of Sciences and Harvard University in the Times Higher Education institutional rankings; the Thomson Reuters-Science Watch website placed the Max Planck Society as the second leading research organization worldwide following Harvard University in terms of the impact of the produced research over science fields. The Max Planck Society and its predecessor Kaiser Wilhelm Society hosted several renowned scientists in their fields, including luminaries such as Otto Hahn, Werner Heisenberg, Albert Einstein.
The organization was established in 1911 as the Kaiser Wilhelm Society, or Kaiser-Wilhelm-Gesellschaft, a non-governmental research organization named for the German emperor. The KWG was one of the world's leading research organizations. In 1946, Otto Hahn assumed the position of President of KWG, in 1948, the society was renamed the Max Planck Society after its former President Max Planck, who died in 1947; the Max Planck Society has a world-leading reputation as a science and technology research organization. In 2006, the Times Higher Education Supplement rankings of non-university research institutions placed the Max Planck Society as No.1 in the world for science research, No.3 in technology research. The domain mpg.de attracted at least 1.7 million visitors annually by 2008 according to a Compete.com study. Since 2004, the Max Planck Research Award is conferred annually to two internationally renowned scientists, one of whom works in Germany and one in another country. Calls for nominations for the award are invited on an annually rotating basis in specific sub-areas of the natural sciences and engineering, the life sciences and the human and social sciences.
The objective of the Max Planck Society and the Alexander von Humboldt Foundation in presenting this joint research award is to give added momentum to specialist fields that are either not yet established in Germany or that deserve to be expanded. Adolf von Harnack Max Planck Carl Bosch Albert Vögler Max Planck Otto Hahn Adolf Butenandt Reimar Lüst Heinz Staab Hans F. Zacher Hubert Markl Peter Gruss Martin Stratmann The Max Planck Society is formally an eingetragener Verein, a registered association with the institute directors as scientific members having equal voting rights; the society has its registered seat in Berlin, while the administrative headquarters are located in Munich. Since June 2014, materials scientist Martin Stratmann has been the President of the Max Planck Society. Funding is provided predominantly from federal and state sources, but from research and licence fees and donations. One of the larger donations was the castle Schloss Ringberg near Kreuth in Bavaria, pledged by Luitpold Emanuel in Bayern.
It passed to the Society after the duke died in 1973, is now used for conferences. The Max Planck Society consists of over 80 research institutes. In addition, the society funds a number of Max Planck Research Groups and International Max Planck Research Schools; the purpose of establishing independent research groups at various universities is to strengthen the required networking between universities and institutes of the Max Planck Society. The research units are located across Europe. In 2007 the Society established its first non-European centre, with an institute on the Jupiter campus of Florida Atlantic University focusing on neuroscience; the Max Planck Institutes operate independently from, though in close cooperation with, the universities, focus on innovative research which does not fit into the university structure due to their interdisciplina
Innsbruck is the capital city of Tyrol in western Austria and the fifth-largest city in Austria. It is in the Inn valley, at its junction with the Wipp valley, which provides access to the Brenner Pass some 30 km to the south. Located in the broad valley between high mountains, the so-called North Chain in the Karwendel Alps to the north, the Patscherkofel and Serles to the south. Innsbruck is an internationally renowned winter sports center, hosted the 1964 and 1976 Winter Olympics as well as the 1984 and 1988 Winter Paralympics. Innsbruck hosted the first Winter Youth Olympics in 2012; the name translates as "Inn Bridge". The earliest traces suggest initial inhabitation in the early Stone Age. Surviving pre-Roman place names show that the area has been populated continuously. In the 4th century the Romans established the army station Veldidena at Oenipons, to protect the economically important commercial road from Verona-Brenner-Augsburg in their province of Raetia; the first mention of Innsbruck dates back to the name Oeni Pontum or Oeni Pons, Latin for bridge over the Inn, an important crossing point over the Inn river.
The Counts of Andechs acquired the town in 1180. In 1248 the town passed into the hands of the Counts of Tyrol; the city's arms show a bird's-eye view of the Inn bridge, a design used since 1267. The route over the Brenner Pass was a major transport and communications link between the north and the south of Europe, the easiest route across the Alps, it was part of a medieval imperial road under special protection of the king. The revenues generated by serving. Innsbruck became the capital of all Tyrol in 1429 and in the 15th century the city became a centre of European politics and culture as Emperor Maximilian I resided in Innsbruck in the 1490s; the city benefited from the emperor's presence. Here a funeral monument for Maximilian was planned and erected by his successors; the ensemble with a cenotaph and the bronze statues of real and mythical ancestors of the Habsburg emperor are one of the main artistic monuments of Innsbruck. A regular postal service between Innsbruck and Mechelen was established in 1490 by the Thurn-und-Taxis-Post.
In 1564 Ferdinand II, Archduke of Austria received the rulership over Tirol and other Further Austrian possessions administered from Innsbruck up to the 18th century. He had Schloss Ambras built and arranged there his unique Renaissance collections nowadays part of Vienna's Kunsthistorisches Museum. Up to 1665 a stirps of the Habsburg dynasty ruled in Innsbruck with an independent court. In the 1620s the first opera house north of the Alps was erected in Innsbruck. In 1669 the university was founded; as a compensation for the court as Emperor Leopold I again reigned from Vienna and the Tyrolean stirps of the Habsburg dynasty had ended in 1665. During the Napoleonic Wars Tyrol was ceded to ally of France. Andreas Hofer led a Tyrolean peasant army to victory in the Battles of Bergisel against the combined Bavarian and French forces, made Innsbruck the centre of his administration; the combined army overran the Tyrolean militia army and until 1814 Innsbruck was part of Bavaria. After the Vienna Congress Austrian rule was restored.
Until 1918, the town was part of the Austrian monarchy, head of the district of the same name, one of the 21 Bezirkshauptmannschaften in the Tyrol province. The Tyrolean hero Andreas Hofer was executed in Mantua. During World War I, the only recorded action taking place in Innsbruck was near the end of the war. On February 20, 1918, Allied planes flying out of Italy raided Innsbruck, causing casualties among the Austrian troops there. No damage to the town is recorded. In November 1918 Innsbruck and all Tyrol were occupied by the 20 to 22 thousand soldiers of the III Corps of the First Italian Army. In 1929, the first official Austrian Chess Championship was held in Innsbruck. In 1938 Austria was annexed by Nazi Germany in the Anschluss. Between 1943 and April 1945, Innsbruck suffered heavy damage. In 1996, the European Union approved further cultural and economic integration between the Austrian province of Tyrol and the Italian autonomous provinces of South Tyrol and Trentino by recognizing the creation of the Euroregion Tyrol-South Tyrol-Trentino.
Innsbruck has a humid continental climate, since it has larger annual temperature differences than most of Central Europe due to its location in the centre of the Continent and its position around mountainous terrains. Winters are very cold and snowy, although the foehn wind sometimes brings pronounced thaws. Spring is brief. Summer is variable and unpredictable. Days can be cool 17 °C and rainy, or sunny and hot, sometimes hitting 34 °C. In summer, as expected for an alpine-influenced climate, the diurnal temperature variation is very high as nights remain cool, being 12 °C on average, but sometimes dipping as low as 6 °C; the average annual temperature is 9 °C. Innsbruck is divided into nine boroughs that were formed from previo
Werner Karl Heisenberg was a German theoretical physicist and one of the key pioneers of quantum mechanics. He published his work in 1925 in a breakthrough paper. In the subsequent series of papers with Max Born and Pascual Jordan, during the same year, this matrix formulation of quantum mechanics was elaborated, he is known for the Heisenberg uncertainty principle, which he published in 1927. Heisenberg was awarded the 1932 Nobel Prize in Physics "for the creation of quantum mechanics", he made important contributions to the theories of the hydrodynamics of turbulent flows, the atomic nucleus, cosmic rays, subatomic particles, he was instrumental in planning the first West German nuclear reactor at Karlsruhe, together with a research reactor in Munich, in 1957. He was a principal scientist in the Nazi German nuclear weapon project during World War II, he travelled to occupied Copenhagen where he discussed the German project with Niels Bohr. Following World War II, he was appointed director of the Kaiser Wilhelm Institute for Physics, which soon thereafter was renamed the Max Planck Institute for Physics.
He was director of the institute until it was moved to Munich in 1958, when it was expanded and renamed the Max Planck Institute for Physics and Astrophysics. Heisenberg was president of the German Research Council, chairman of the Commission for Atomic Physics, chairman of the Nuclear Physics Working Group, president of the Alexander von Humboldt Foundation. Werner Karl Heisenberg was born in Würzburg, Germany, to Kaspar Ernst August Heisenberg, a secondary school teacher of classical languages who became Germany's only ordentlicher Professor of medieval and modern Greek studies in the university system, his wife, Annie Wecklein, he studied physics and mathematics from 1920 to 1923 at the Ludwig Maximilian University of Munich and the Georg-August University of Göttingen. At Munich, he studied under Wilhelm Wien. At Göttingen, he studied physics with James Franck and mathematics with David Hilbert, he received his doctorate at Munich under Sommerfeld. At Göttingen, under Born, he completed his habilitation in 1924 with a Habilitationsschrift on the anomalous Zeeman effect.
Because Sommerfeld had a sincere interest in his students and knew of Heisenberg's interest in Niels Bohr's theories on atomic physics, Sommerfeld took Heisenberg to Göttingen to attend the Bohr Festival of June 1922. At the event, Bohr was a guest lecturer and gave a series of comprehensive lectures on quantum atomic physics. There, Heisenberg met Bohr for the first time, it had a significant and continuing effect on him. Heisenberg's doctoral thesis, the topic of, suggested by Sommerfeld, was on turbulence; the problem of stability was investigated by the use of the Orr–Sommerfeld equation, a fourth order linear differential equation for small disturbances from laminar flow. He returned to this topic after World War II. In his youth he was a member and Scoutleader of the Neupfadfinder, a German Scout association and part of the German Youth Movement. In August 1923 Robert Honsell and Heisenberg organized a trip to Finland with a Scout group of this association from Munich. Heisenberg arrived at Munich in 1919 as a member of the Freikorps to fight the Bavarian Soviet Republic established a year earlier.
Five decades he recalled those days as youthful fun, like "playing cops and robbers and so on. From 1924 to 1927, Heisenberg was a Privatdozent at Göttingen, meaning he was qualified to teach and examine independently, without having a chair. From 17 September 1924 to 1 May 1925, under an International Education Board Rockefeller Foundation fellowship, Heisenberg went to do research with Niels Bohr, director of the Institute of Theoretical Physics at the University of Copenhagen, his seminal paper, "Über quantentheoretische Umdeutung kinematischer und mechanischer Beziehungen", was published in September 1925. He returned to Göttingen and, with Max Born and Pascual Jordan over a period of about six months, developed the matrix mechanics formulation of quantum mechanics. On 1 May 1926, Heisenberg began his appointment as a university lecturer and assistant to Bohr in Copenhagen, it was in Copenhagen, in 1927, that Heisenberg developed his uncertainty principle, while working on the mathematical foundations of quantum mechanics.
On 23 February, Heisenberg wrote a letter to fellow physicist Wolfgang Pauli, in which he first described his new principle. In his paper on the principle, Heisenberg used the word "Ungenauigkeit", not uncertainty, to describe it. In 1927, Heisenberg was appointed ordentlicher Professor of theoretical physics and head of the department of physics at the University of Leipzig. In his first paper published from Leipzig, Heisenberg used the Pauli exclusion principle to solve the mystery of ferromagnetism. During Heisenberg's tenure at Leipzig, the high quality of the doctoral students and post-graduate and research associates who studied and worked with him is clear from the acclaim many earned. At various times they included Erich Bagge, Felix Bloch, Ugo Fano, Siegfried Flügge, William Vermillion Houston, Friedrich Hund, Robert S. Mulliken, Rudolf Peierls, George Placzek, Isidor Isaac Rabi, Fritz Sauter, John C. Slater, Edward Teller, John Hasbrouck van Vleck, Victor Frederick Weisskopf, Carl Friedrich von Weizsäcker, Gregor Wentzel, Clarence Zener.
A particle accelerator is a machine that uses electromagnetic fields to propel charged particles to high speeds and energies, to contain them in well-defined beams. Large accelerators are used for basic research in particle physics; the most powerful accelerator is the Large Hadron Collider near Geneva, built by the European collaboration 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 KEKB at KEK in Japan, RHIC at Brookhaven National Laboratory, the Tevatron at Fermilab, Illinois. Accelerators are 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 implanters for manufacture of semiconductors, accelerator mass spectrometers for measurements of rare isotopes such as radiocarbon.
There are more than 30,000 accelerators in operation around the world. There are two basic classes of accelerators: electrodynamic accelerators. Electrostatic accelerators use static electric fields to accelerate particles; the most common types are the Cockcroft -- the Van de Graaff generator. A small-scale example of this class is the cathode ray tube in an ordinary old television set; the achievable kinetic energy for particles in these devices is determined by the accelerating voltage, limited by electrical breakdown. Electrodynamic or electromagnetic accelerators, on the other hand, use changing electromagnetic fields to accelerate particles. Since in these types the particles can pass through the same accelerating field multiple times, the output energy is not limited by the strength of the accelerating field; this class, first developed in the 1920s, is the basis for most modern large-scale accelerators. Rolf Widerøe, Gustav Ising, Leó Szilárd, Max Steenbeck, Ernest Lawrence are considered pioneers of this field and building the first operational linear particle accelerator, the betatron, the cyclotron.
Because colliders can give evidence of the structure of the subatomic world, accelerators were referred to as atom smashers in the 20th century. Despite the fact that most accelerators propel subatomic particles, the term persists in popular usage when referring to particle accelerators in general. Beams of high-energy particles are useful for fundamental and applied research in the sciences, in many technical and industrial fields unrelated to fundamental research, it has been estimated that there are 30,000 accelerators worldwide. Of these, only about 1% are research machines with energies above 1 GeV, while about 44% are for radiotherapy, 41% for ion implantation, 9% for industrial processing and research, 4% for biomedical and other low-energy research; the bar graph shows the breakdown of the number of industrial accelerators according to their applications. The numbers are based on 2012 statistics available from various sources, including production and sales data published in presentations or market surveys, data provided by a number of manufacturers.
For the most basic inquiries into the dynamics and structure of matter and time, physicists seek the simplest kinds of interactions at the highest possible energies. These entail particle energies of many GeV, the interactions of the simplest kinds of particles: leptons and quarks for the matter, or photons and gluons for the field quanta. Since isolated quarks are experimentally unavailable due to color confinement, the simplest available experiments involve the interactions of, leptons with each other, second, of leptons with nucleons, which are composed of quarks and gluons. To study the collisions of quarks with each other, scientists resort to collisions of nucleons, which at high energy may be usefully considered as 2-body interactions of the quarks and gluons of which they are composed, thus elementary particle physicists tend to use machines creating beams of electrons, positrons and antiprotons, interacting with each other or with the simplest nuclei at the highest possible energies hundreds of GeV or more.
The largest and highest energy particle accelerator used for elementary particle physics is the Large Hadron Collider at CERN, operating since 2009. Nuclear physicists and cosmologists may use beams of bare atomic nuclei, stripped of electrons, to investigate the structure and properties of the nuclei themselves, of condensed matter at high temperatures and densities, such as might have occurred in the first moments of the Big Bang; these investigations involve collisions of heavy nuclei – of atoms like iron or gold – at energies of several GeV per nucleon. The largest such particle accelerator is the Relativistic Heavy Ion Collider at Brookhaven National Laboratory. Particle accelerators can produce proton beams, which can produce proton-rich medical or research isotopes as opposed to the neutron-rich ones made in fission reactors. An example of this type of machine is LANSCE at Los Alamos. Besides being of fundamental interest, electrons accelerated in the magnetic field causes the high energy electrons to emit extre
Accelerator physics is a branch of applied physics, concerned with designing and operating particle accelerators. As such, it can be described as the study of motion and observation of relativistic charged particle beams and their interaction with accelerator structures by electromagnetic fields, it is related to other fields: Microwave engineering. Optics with an emphasis on geometrical optics and laser physics. Computer technology with an emphasis on digital signal processing; the experiments conducted with particle accelerators are not regarded as part of accelerator physics, but belong to, e.g. particle physics, nuclear physics, condensed matter physics or materials physics. The types of experiments done at a particular accelerator facility are determined by characteristics of the generated particle beam such as average energy, particle type and dimensions. While it is possible to accelerate charged particles using electrostatic fields, like in a Cockcroft-Walton voltage multiplier, this method has limits given by electrical breakdown at high voltages.
Furthermore, due to electrostatic fields being conservative, the maximum voltage limits the kinetic energy, applicable to the particles. To circumvent this problem, linear particle accelerators operate using time-varying fields. To control this fields using hollow macroscopic structures through which the particles are passing, the frequency of such acceleration fields is located in the radio frequency region of the electromagnetic spectrum; the space around a particle beam is evacuated to prevent scattering with gas atoms, requiring it to be enclosed in a vacuum chamber. Due to the strong electromagnetic fields that follow the beam, it is possible for it to interact with any electrical impedance in the walls of the beam pipe; this may be in the form of an inductive/capacitive impedance. These impedances will induce wakefields that can interact with particles. Since this interaction may have negative effects, it is studied to determine its magnitude, to determine any actions that may be taken to mitigate it.
Due to the high velocity of the particles, the resulting Lorentz force for magnetic fields, adjustments to the beam direction are controlled by magnetostatic fields that deflect particles. In most accelerator concepts, these are applied by dedicated electromagnets with different properties and functions. An important step in the development of these types of accelerators was the understanding of strong focusing. Dipole magnets are used to guide the beam through the structure, while quadrupole magnets are used for beam focusing, sextupole magnets are used for correction of dispersion effects. A particle on the exact design trajectory of the accelerator only experiences dipole field components, while particles with transverse position deviation x are re-focused to the design orbit. For preliminary calculations, neglecting all fields components higher than quadrupolar, an inhomogenic Hill differential equation d 2 d s 2 x + k x = 1 ρ Δ p p can be used as an approximation, with a non-constant focusing force k, including strong focusing and weak focusing effects the relative deviation from the design beam impulse Δ p / p the trajectory radius of curvature ρ, the design path length s,thus identifying the system as a parametric oscillator.
Beam parameters for the accelerator can be calculated using Ray transfer matrix analysis. The general equations of motion originate from relativistic Hamiltonian mechanics, in all cases using the Paraxial approximation. In the cases of nonlinear magnetic fields, without the paraxial approximation, a Lie transform may be used to construct an integrator with a high degree of accuracy. There are many different software packages available for modeling the different aspects of accelerator physics. One must model the elements that create the electric and magnetic fields, one must model the charged particle evolution within those fields. A popular code for beam dynamics, designed by CERN is Methodical Accelerator Design. A vital component of any accelerator are the diagnostic devices that allow various properties of the particle bunches to be measured. A typical machine may use many different types of measurement device in order to measure different properties; these include Beam Position Monitors to measure the position of th