| 单词 | positron |
| 例句 | The discovery of the positron in 1932 confirmed Dirac’s theory and led to his being awarded the Nobel Prize for physics in 1933. A Brief History of Time: And Other Essays 1988-01-01T00:00:00Z They provided precise ionization data, spelled out their theory on how positrons emitted by the bombarded atoms transmuted into gamma rays, and carefully avoided any speculation about the significance of the new phenomenon. Big Science 2015-07-07T00:00:00Z As they expected, the bombardments drove positrons from the target foils. Big Science 2015-07-07T00:00:00Z In 1930 he predicted the existence of the positron, a positively charged electron. Big Science 2015-07-07T00:00:00Z And a positronic brain, which with ten pounds of matter and a few quintillions of positrons runs the whole show. I, Robot 1950-12-02T00:00:00Z It also predicted that the electron should have a partner: an antielectron, or positron. A Brief History of Time: And Other Essays 1988-01-01T00:00:00Z He failed because his detection apparatus was not capable of sensing neutrons and positrons—that was an understandable oversight, for neither particle yet had been discovered. Big Science 2015-07-07T00:00:00Z They had bombarded dozens of elements with deuterons and assiduously tracked emissions of alpha particles during the bombardments; but the continued emission of electrons or positrons after the bombardments ended had escaped their notice. Big Science 2015-07-07T00:00:00Z The result of their bombardments of boron and other light elements by alpha rays, moreover, had led them to propose that the proton was composed of a neutron and a positive electron, or positron. Big Science 2015-07-07T00:00:00Z Dirac's beautiful equation is just like that – it describes the electron and predicts the existence of its anti-matter partner, the positron. The beauty of the Higgs boson 2012-08-04T23:05:33Z The signature of positrons has been detected by the Fermi Gamma-ray telescope above storms and the annihilation of this antimatter with normal matter builds the intensity of the gamma ray flashes. What goes on when lightning strikes? 2013-05-25T23:07:12Z Swap the positron pump for global warming and Asmiov's contest against stupidity seems ever more urgent. Back to the Hugos: The Gods Themselves by Isaac Asimov 2011-01-06T15:34:14Z Positronic compounds, namely bound states of positrons with regular atoms, molecules, or ions, represent an intriguing aspect of positron-matter interactions and have been studied experimentally via observation of positron annihilation in gases. Ionic crystal generates molecular ions upon positron irradiation, finds new study 2023-10-10T04:00:00Z Despite some modest sources of antimatter -- like positrons emitted from the decay of potassium, even within a banana -- scientists do not see much of it in the universe. Down goes antimatter! Gravity's effect on matter's elusive twin is revealed 2023-09-27T04:00:00Z The antimatter counterpart to the negatively charged electron, for example, is the positron, which has the same mass and spin but a positive charge rather than a negative one. What Happens if You Drop Antimatter? New Gravitational Test Sees First Fall 2023-09-27T04:00:00Z The antiprotons and positrons are then sent into a giant magnet, where they mix to form thousands of atoms of antihydrogen. Scientists get closer to solving mystery of antimatter 2023-09-27T04:00:00Z Though the novel positron approach turned out not to be viable, across the Atlantic, U.S. researchers had heard about the Italian effort and begun to look into things themselves. Particle Physicists Dream of a Muon Collider 2023-08-28T04:00:00Z It may be possible to generate new molecules and ions via the formation of positron compounds, but no research has ever been done from such a perspective. Ionic crystal generates molecular ions upon positron irradiation, finds new study 2023-10-10T04:00:00Z Some of the surviving electron antineutrinos will slam into a proton in the scintillator, producing an energetic positron that results in a flash of light. China’s new underground lab could answer long-standing neutrino mystery 2023-08-22T04:00:00Z They then harvest positively charged positrons from a radioactive source, trapping these antimatter particles together in a vacuum to shield them from normal matter. What Happens if You Drop Antimatter? New Gravitational Test Sees First Fall 2023-09-27T04:00:00Z He cited as an example an experiment at Stanford that involved spraying electrons and positrons into a ball of niobium to detect electric charges. Ian Hacking, Eminent Philosopher of Science and Much Else, Dies at 87 2023-05-28T04:00:00Z The intention is for the FCC to begin as a Higgs factory that will collide electrons and positrons. Particle Physicists Dream of a Muon Collider 2023-08-28T04:00:00Z This process, known as electron-stimulated desorption, motivated the team to explore what would happen if a crystal was instead bombarded with positrons. Ionic crystal generates molecular ions upon positron irradiation, finds new study 2023-10-10T04:00:00Z An electron, for instance, can appear along with a positron, which is positively charged; the two charges cancel each other out to preserve the total charge of zero. How Much Does ‘Nothing’ Weigh? 2023-04-29T04:00:00Z The antiprotons and positrons attract, forming neutrally charged atoms of antihydrogen, the antimatter version of hydrogen. What Happens if You Drop Antimatter? New Gravitational Test Sees First Fall 2023-09-27T04:00:00Z Wu and Shaknov packed the copper isotope into a tiny capsule, eight millimeters long, and waited for electrons and positrons to collide inside the apparatus. The Little-Known Origin Story behind the 2022 Nobel Prize in Physics 2023-03-16T04:00:00Z Neuroimaging techniques such as magnetic resonance imaging or positron emission tomography can reveal FTD-indicating signs of damage or functional abnormalities in the brain. Understanding Frontotemporal Dementia, the Leading Cause of Dementia in People Under Age 60 2023-03-09T05:00:00Z Notably, this is the first-ever report of molecular ions being ejected upon positron irradiation. Ionic crystal generates molecular ions upon positron irradiation, finds new study 2023-10-10T04:00:00Z Rarely, a proton in the oil will absorb an electron antineutrino to turn into a neutron while ejecting a positron—sort of the reverse of beta decay. Nuclear reactor mystery solved, with no need for new particles 2023-01-11T05:00:00Z The most frequent decay pattern produced another type of meson, called a kaon, plus pairs of particles and their antiparticles—either an electron and a positron or a muon and an antimuon. Hint of Crack in Standard Model Vanishes in LHC Data 2022-12-22T05:00:00Z In the lab, Wu and Shaknov used it to bombard a sheet of copper with deuterons, generating an unstable isotope, Cu 64, as a source of positrons—the antimatter. The Little-Known Origin Story behind the 2022 Nobel Prize in Physics 2023-03-16T04:00:00Z They are, by and large, tired of smashing protons—essentially messy bundles of quarks—and would much prefer the more tidy collisions of electrons and positrons. Physicists Struggle to Unite Around Future Plans 2022-09-08T04:00:00Z In the case of LiF crystals, these positrons may attract two neighboring fluorine negative ions on the surface to form a positronic compound. Ionic crystal generates molecular ions upon positron irradiation, finds new study 2023-10-10T04:00:00Z As the positron streaks through the oil, it produces light in proportion to the energy of the original neutrino. Nuclear reactor mystery solved, with no need for new particles 2023-01-11T05:00:00Z The standard model predicted that the two types of pair should occur with roughly the same frequency, but LHCb data suggested that the electron–positron pairs occurred more often. Hint of Crack in Standard Model Vanishes in LHC Data 2022-12-22T05:00:00Z When a positron and an electron collide, they annihilate each other, releasing two photons that fly apart in opposite directions. The Little-Known Origin Story behind the 2022 Nobel Prize in Physics 2023-03-16T04:00:00Z Furthermore, the two positrons produced will find two electrons and annihilate to form four more γ rays, for a total of six. College Physics for AP Courses 2015-08-12T00:00:00Z It is an attractive particle for scientists because the use of positrons has led to important insights and developments in the fields of elementary particle physics, atomic physics, materials science, astrophysics, and medicine. Ionic crystal generates molecular ions upon positron irradiation, finds new study 2023-10-10T04:00:00Z The most common are protons, neutrons, alpha particles, beta particles, positrons, and gamma rays, as shown in Figure 21.4. Chemistry 2019-02-14T00:00:00Z The antielectron is the positron, which has the same mass as the electron but is positively charged. Astronomy 2016-10-13T00:00:00Z The cancer vanished in every single patient, undetectable by physical exam; endoscopy; positron emission tomography, or PET scans; or MRI scans. A Cancer Trial’s Unexpected Result: Remission in Every Patient 2022-06-05T04:00:00Z In this case, an electron and a positron convert all their mass into two identical energy rays, which move away in opposite directions to keep total momentum zero as it was before. College Physics for AP Courses 2015-08-12T00:00:00Z For instance, positrons are known to be components of antimatter. Ionic crystal generates molecular ions upon positron irradiation, finds new study 2023-10-10T04:00:00Z For example, when a positron and an electron collide, both are annihilated and two gamma ray photons are created: Chemistry 2019-02-14T00:00:00Z Incoming neutrinos interact with the water to produce positrons and electrons, which move rapidly through the water and emit deep blue light. Astronomy 2016-10-13T00:00:00Z The positron emission tomography technology that was used in the new study was designed to identify the sites of coronavirus infection in a living animal. The coronavirus invades cells in the penis and testicles of monkeys, researchers discover. 2022-03-01T05:00:00Z A positron is an antimatter version of the electron, having exactly the same mass. College Physics for AP Courses 2015-08-12T00:00:00Z According to this model, as positrons are injected into a solid, some of them return to the surface after losing their energy. Ionic crystal generates molecular ions upon positron irradiation, finds new study 2023-10-10T04:00:00Z Note that positrons are exactly like electrons, except they have the opposite charge. Chemistry 2019-02-14T00:00:00Z The most abundant elements in cosmic rays are the nuclei of hydrogen and helium, but electrons and positrons are also found. Astronomy 2016-10-13T00:00:00Z In the first step of this fusion process, two protons inside the sun fuse into a deuteron while giving off a neutrino and a positron—the antiparticle of the electron. Readers Respond to the October 2021 Issue 2022-02-20T05:00:00Z In addition to the large synchrotrons that produce colliding beams of protons and antiprotons, there are other large electron- positron accelerators. College Physics for AP Courses 2015-08-12T00:00:00Z If this process were to occur, it would result in an electron and its antimatter partner, a positron, which would show up as a different signal than a plain electron. Can Sterile Neutrinos Exist? 2021-11-04T04:00:00Z Whether electron capture or positron emission occurs is difficult to predict. Chemistry 2019-02-14T00:00:00Z Solar energy is produced by interactions of particles—that is, protons, neutrons, electrons, positrons, and neutrinos. Astronomy 2016-10-13T00:00:00Z And it will probe the mysterious origin of positrons—the antimatter counterparts of electrons—seen close to the Milky Way’s center. News at a glance: Climate promises, a predatory ‘Hydra’ publisher, and tracking the birth of elements 2021-10-27T04:00:00Z In 1932, American physicist Carl Anderson discovered the positron in cosmic ray studies. College Physics for AP Courses 2015-08-12T00:00:00Z Physicists do this by monitoring one of the decay particles they create: electrons, from decays of negatively charged muons, or positrons—the antiparticle version of electrons—from decays of positively charged muons. Weird Muons May Point to New Particles and Forces of Nature 2021-09-14T04:00:00Z The principal source of energy in the sun is a net fusion reaction in which four hydrogen nuclei fuse and produce one helium nucleus and two positrons. Chemistry 2019-02-14T00:00:00Z Also produced in this reaction are a positron, which is an antielectron, and an elusive particle named the neutrino. Astronomy 2016-10-13T00:00:00Z The team first identified 55 people from that group who showed signs of consciousness according to standard tests, including positron emission tomography scans, which measure brain metabolism, and MRI. Newly detailed nerve links between brain and other organs shape thoughts, memories, and feelings 2021-06-10T04:00:00Z Muons were discovered in cosmic ray experiments in 1937, and they seemed to be heavy, unstable versions of electrons and positrons. College Physics for AP Courses 2015-08-12T00:00:00Z By determining the energy and arrival time of the electrons or positrons, scientists can deduce the spin direction of the parent muon. Weird Muons May Point to New Particles and Forces of Nature 2021-09-14T04:00:00Z Positron decay is the conversion of a proton into a neutron with the emission of a positron. Chemistry 2019-02-14T00:00:00Z As the universe expanded and cooled, protons and neutrons formed first, then came electrons and positrons. Astronomy 2016-10-13T00:00:00Z The muons are collected and channeled into an orderly circular path around the magnet, which they will circle, at most, a few thousand times before they decay into positrons. Long-Awaited Muon Measurement Boosts Evidence for New Physics 2021-04-07T04:00:00Z The electron, positron, muons, and neutrinos are examples of leptons, the name meaning low mass. College Physics for AP Courses 2015-08-12T00:00:00Z As they orbit, each muon decays to produce a positron, which flies into one of the detectors lining the ring. The cloak-and-dagger tale behind this year’s most anticipated result in particle physics 2021-01-27T05:00:00Z Like positron emission, electron capture occurs for “proton-rich” nuclei that lie below the band of stability. Chemistry 2019-02-14T00:00:00Z Since it is antimatter, this positron will instantly collide with a nearby electron, and both will be annihilated, producing electromagnetic energy in the form of gamma-ray photons. Astronomy 2016-10-13T00:00:00Z When the muon’s time is up, it decays into a positron that is emitted in the direction of the hour hand. Long-Awaited Muon Measurement Boosts Evidence for New Physics 2021-04-07T04:00:00Z How many electrons and positrons could be produced this way? College Physics for AP Courses 2015-08-12T00:00:00Z To hide the true frequency at which the flux of positrons oscillates, the experiment runs on a clock that ticks not in real nanoseconds, but at an unknown frequency, chosen at random. The cloak-and-dagger tale behind this year’s most anticipated result in particle physics 2021-01-27T05:00:00Z Electron capture has the same effect on the nucleus as does positron emission: The atomic number is decreased by one and the mass number does not change. Chemistry 2019-02-14T00:00:00Z In addition to the positron, the fusion of two hydrogen atoms to form deuterium results in the emission of a neutrino. Astronomy 2016-10-13T00:00:00Z But if that hand turns at a rate different from theory—say, a tick too fast—the positron decay will end up pointing in a slightly different direction. Long-Awaited Muon Measurement Boosts Evidence for New Physics 2021-04-07T04:00:00Z Two very small studies have documented brain inflammation in ME/CFS, one using positron emission tomography and another employing a technique called magnetic resonance spectroscopy. What If You Never Get Better From Covid-19? 2021-01-21T05:00:00Z In stars massive enough to make such a beastly hole, the interior grows so hot when collapsing that light spontaneously creates pairs of electrons and positrons. These Black Holes Shouldn’t Exist, but There They Are 2020-09-02T04:00:00Z Which of the following nuclei is most likely to decay by positron emission? Chemistry 2019-02-14T00:00:00Z In the crowded conditions of the very early universe, however, neutrinos ran into so many electrons and positrons that they experienced frequent interactions despite their “antisocial” natures. Astronomy 2016-10-13T00:00:00Z It was “radiation” and “positron” with no real content. How scientific is Christopher Nolan's 'Tenet'? We asked an expert 2020-09-04T04:00:00Z A property of positronium—an exotic atom consisting of an electron bound to its antimatter partner, a positron—differs significantly from theoretical predictions, a team of physicists reports. Tantalizing oddity found in exotic atom—but physicists aren’t hyping it 2020-08-25T04:00:00Z It would be built in an underground tunnel near CERN’s location outside Geneva, Switzerland, and smash together electrons and their antimatter partners, positrons, by the middle of the century. Mathematical boycott, supercollider plan and lava-lamp cells 2020-06-23T04:00:00Z It would collide electrons with positrons to produce myriad Higgs bosons and dissect their finer properties. Daily briefing: DNA hints at an ancient dynasty in Neolithic Ireland 2020-06-18T04:00:00Z The new machine would collide electrons with their antimatter partners, positrons, by the middle of the century. CERN makes bold push to build €21-billion super-collider 2020-06-18T04:00:00Z When T2K runs with antineutrino beams, such interactions produce either an antimuon or a positron, whose signals parallel those generated by the muons and electrons. Skewed neutrino behavior could help explain matter’s dominion over antimatter 2020-04-15T04:00:00Z Within a fraction of a microsecond, the electron and the positron collide and annihilate each other in a flash of gamma rays. Tantalizing oddity found in exotic atom—but physicists aren’t hyping it 2020-08-25T04:00:00Z The best-known example is the antielectron, or positron. Matter–antimatter symmetry violated 2020-04-14T04:00:00Z The machine won over competitors, including a linear electron–positron collider and one that would accelerate muons instead. Daily briefing: DNA hints at an ancient dynasty in Neolithic Ireland 2020-06-18T04:00:00Z Unlike protons, which are made of a jumble of quarks and gluons, electrons and positrons are “fundamental”—just themselves. Japan Inches Forward with Plans to Host Next Big Particle Collider 2020-02-26T05:00:00Z The gaps between energy levels in antihydrogen — the simplest antimatter atom, with one antiproton and one positron — seem to be identical to those measured in ordinary hydrogen. Daily briefing: Coronavirus vaccine ready for human clinical trials, says US biotech company 2020-02-24T05:00:00Z Researchers may also struggle to explain away the discrepancy with new theories, such as some new quantum particle that flits between the electron and positron. Tantalizing oddity found in exotic atom—but physicists aren’t hyping it 2020-08-25T04:00:00Z A facility called the Antiproton Decelerator delivers antiprotons to this experiment, with a source of radioactive sodium providing positrons. Fundamental symmetry tested using antihydrogen 2020-02-18T05:00:00Z “The drop-off of positrons is interesting, whether it is caused by dark matter, pulsars or something else,” says M.I.T. particle physicist Tracy Slatyer. Space Station Dark Matter Experiment Gets Vital Repairs 2019-12-11T05:00:00Z The positrons occur in natural radioactive processes, such as in the decay of Potassium-40. Why Is There More Matter Than Antimatter? 2019-03-21T04:00:00Z Electrons would be accelerated from one end of a several-mile-long tunnel, positrons from the other—and both would meet to smash head-on in the middle. Japan Delays Decision for Hosting Next Big Particle Collider 2019-03-08T05:00:00Z The ILC would smash together electrons with their antimatter counterparts, positrons, and study the products. Plans for world’s next major collider stuck in limbo 2019-03-06T05:00:00Z Because electrons and positrons radiate copious x-rays as they bend around a ring, the circular colliders would run much less efficiently than a linear collider. Lack of discoveries is damaging prospects for next big particle collider 2019-02-28T05:00:00Z The positron’s signal is difficult for the detector to distinguish from that of an electron from a solar neutrino. Gigantic Japanese detector prepares to catch neutrinos from supernovae 2019-02-26T05:00:00Z Almost all of them are protons, electrons, and light nuclei such as helium, but a precious few consist of antimatter particles such as positrons. Space magnet homes in on clue to dark matter 2019-02-06T05:00:00Z The results lend support to two previously proposed mechanisms for how mysterious jets are powered: turbulent currents of positrons and electrons, and particles with negative energy. Daily briefing: Learn to take exceptional scientific photos 2019-01-30T05:00:00Z Because electrons and positrons are fundamental particles, the collisions would be cleaner and easier to study than the proton–proton smashes at the LHC. Plans for world’s next major collider stuck in limbo 2019-03-06T05:00:00Z These fields would, according to astrophysicists’ prevailing explanation, carry away some of the black hole’s energy and rotational momentum, as well as create more electrons and positrons. Black-hole jets begin to reveal their antimatter secrets 2019-01-29T05:00:00Z This collision releases a neutron and a positron, the antimatter version of the electron. Gigantic Japanese detector prepares to catch neutrinos from supernovae 2019-02-26T05:00:00Z The AMS paper acknowledges that dark matter annihilation is just one possible explanation for the positrons. Space magnet homes in on clue to dark matter 2019-02-06T05:00:00Z It, too, would collide electrons and positrons to generate Higgs bosons. European physicists unveil plans for a particle collider that would be longer than the Panama Canal 2019-01-15T05:00:00Z At first it would collide electrons and positrons, their positive cousins. Cern draws up plans for collider four times the size of Large Hadron 2019-01-15T05:00:00Z Their results show turbulent currents of positrons and electrons moving in opposite directions to each other, as both swirl in a disc around the black hole’s equator. Black-hole jets begin to reveal their antimatter secrets 2019-01-29T05:00:00Z The proposal involves digging a new tunnel under Cern and then installing a ring that would initially collide electrons with their positively charged counterparts, positrons. Cern plans for even larger hadron collider 2019-01-15T05:00:00Z Cosmic ray protons emerging from remnants of supernova explosions regularly slam into atomic nuclei in interstellar space to create "secondary" cosmic rays, including positrons. Space magnet homes in on clue to dark matter 2019-02-06T05:00:00Z For a long time, the leading candidate for Next Big Physics Machine has been the International Linear Collider, which would fire electrons and their antimatter opposites, positrons, at each other. It’s Intermission for the Large Hadron Collider 2018-12-21T05:00:00Z The proposed accelerator — which would be more than 20 kilometres long — would enable physicists to detect the products of precise collisions between electrons and their antimatter counterparts, positrons. Japanese science committee questions the project’s multi-billion-dollar price tag — but decision rests with the government. 2018-12-18T05:00:00Z The collider will produce Higgs bosons by smashing together electrons and their antimatter counterparts, positrons. Chinese mega ‘LHC’, Scotland’s research and Plan S consultation 2018-11-27T05:00:00Z Smashing electrons into their antimatter counterparts, positrons, results in cleaner collisions that typically produce one Z particle and one Higgs boson at a time, says Bill Murray of The University of Warwick in Coventry, U.K. China unveils design for $5 billion particle smasher 2018-11-16T05:00:00Z In this study, researchers used positron emission tomography, also called a PET scan. Pulling all-nighters may damage your brain 2018-07-21T04:00:00Z An electron and its antiparticle, a positron, have identical properties except for charge, but the charge of the Majorana particle would be zero. What Are the Limits of Manipulating Nature? 2018-05-25T04:00:00Z As electron and positrons are fundamental particles, their collisions would be cleaner than the proton–proton collisions at the LHC. Japanese science committee questions the project’s multi-billion-dollar price tag — but decision rests with the government. 2018-12-18T05:00:00Z The team found that positron beams created as much light as did electron beams with hundreds of times more kinetic energy. Antimatter’s annihilation burns brightly 2018-04-15T04:00:00Z When this collision occurs, the proton transforms into a neutron and ejects a positron, the antimatter version of an electron. How to Spot a Nuclear Bomb Program? Look for Ghostly Particles 2018-03-27T04:00:00Z Quantum mechanics is all about how the Universe works at the smallest level — how teeny particles like electrons and positrons move and connect. How Stephen Hawking’s biggest achievement linked opposing worlds of physics 2018-03-15T04:00:00Z But most alluring, Li says, would be showing that light could tear electrons and their antimatter counterparts, positrons, from empty space—a phenomenon known as "breaking the vacuum." Physicists are planning to build lasers so powerful they could rip apart empty space 2018-01-24T05:00:00Z Suppliers want to tamp down fears about reliability, physicians and pharmacists say, to dissuade them from seeking alternative imaging methods when possible, like positron emission tomography, a costly and complex type of medical scan. Inside the Global Relay Race to Deliver Moly-99 2018-01-12T05:00:00Z The findings suggest that positrons annihilate on collision with particles in the semiconductor, causing the positrons to convert more of their energy into light than electrons do. Antimatter’s annihilation burns brightly 2018-04-15T04:00:00Z Fan, Y. Z., Zhang, B. & Chang, J. Electron/positron excesses in the cosmic ray spectrum and possible interpretations. Direct detection of a break in the teraelectronvolt cosmic-ray spectrum of electrons and positrons 2017-11-28T05:00:00Z But, he adds, Enoto's team's explanation does not solve all puzzles related to positrons in the atmosphere. Lightning makes new isotopes 2017-11-21T05:00:00Z But colliding two beams makes it easier, because this jacks up the momentum needed to generate the mass for electrons and positrons. Physicists are planning to build lasers so powerful they could rip apart empty space 2018-01-24T05:00:00Z Here we report ground-based observations of neutron and positron signals after lightning. Photonuclear reactions triggered by lightning discharge 2017-11-21T05:00:00Z Sometimes spinning more than 700 times a second, they churn up their surroundings and smash particles into one another; this includes electrons and positrons caught in the pulsar’s whirling grasp. Mysterious Particles Are Slamming Into Earth—But Why? 2017-11-16T05:00:00Z The spectrum of cosmic-ray electrons and positrons that arrive at Earth potentially contains information about the sources that accelerated them, and may reveal dark-matter annihilation. Direct detection of a break in the teraelectronvolt cosmic-ray spectrum of electrons and positrons 2017-11-28T05:00:00Z His detector spotted a signature of positrons only for a fraction of a second — too short to originate from nuclear decay, he says. Lightning makes new isotopes 2017-11-21T05:00:00Z Over extremely short time scales, pairs of electrons and positrons, their antimatter counterparts, flicker into existence, born of quantum mechanical uncertainty. Physicists are planning to build lasers so powerful they could rip apart empty space 2018-01-24T05:00:00Z The centre energy of the prolonged line emission corresponds to electron–positron annihilation, providing conclusive evidence of positrons being produced after the lightning. Photonuclear reactions triggered by lightning discharge 2017-11-21T05:00:00Z We don’t see a lot of positrons in nature here on Earth. Mysterious Particles Are Slamming Into Earth—But Why? 2017-11-16T05:00:00Z For instance, the antiparticle of the negatively charged electron is the positively charged positron, a particle that makes up the bulk of antimatter striking the top of Earth’s atmosphere from outer space. Through a Gas, Darkly: Scientists Trace the Origins of Earth's Antimatter 2017-11-16T05:00:00Z Physicists say this is the unmistakable signature of positrons annihilating in a puff of energy as they hit electrons in the surrounding matter. Lightning makes new isotopes 2017-11-21T05:00:00Z By contrast, the ILC would collide electrons and positrons head on after accelerating them in thousands of superconducting cavities joined end to end. Physicists shrink plans for next major collider 2017-11-08T05:00:00Z They conclude that the positrons arise from the decay of neutrons after the lightning. Photonuclear reactions triggered by lightning discharge 2017-11-21T05:00:00Z Antiproton and positron plasmas are prepared on either side of the production region before being mixed to form antihydrogen at the centre of the minimum-B trap. Observation of the hyperfine spectrum of antihydrogen : Nature : Nature Research 2017-08-01T04:00:00Z Ever since, astrophysicists have been debating where all these excess positrons might come from. Through a Gas, Darkly: Scientists Trace the Origins of Earth's Antimatter 2017-11-16T05:00:00Z It decays radioactively over the next minute or so; in so doing, it emits a positron, which almost immediately annihilates with an electron, producing two 511-keV photons. Lightning makes new isotopes 2017-11-21T05:00:00Z Each requires halving the length of the superconducting electron–positron accelerators, but two of the options retain extra tunnel space to accommodate future upgrades. Physicists shrink plans for next major collider 2017-11-08T05:00:00Z Measurements of the electron and its antiparticle, the positron, showed their spin magnetic moments to be the same to within 4 parts in 1012. Hans Dehmelt (1922-2017) : Nature : Nature Research 2017-05-16T04:00:00Z Antiproton and positron plasmas are prepared on either side of the production region before being mixed to form antihydrogen at the centre of the minimum-B trap. Observation of the hyperfine spectrum of antihydrogen : Nature : Nature Research 2017-08-01T04:00:00Z They found each pulsar is surrounded by a kind of murky “fog,” from which relatively few positrons can escape to strike Earth. Through a Gas, Darkly: Scientists Trace the Origins of Earth's Antimatter 2017-11-16T05:00:00Z A precious few are antiprotons and positrons: the antimatter counterparts of protons and electrons. Giant space magnet may have trapped antihelium, raising idea of lingering pools of antimatter in the cosmos 2017-04-19T04:00:00Z But Hooper and his colleagues also calculated how many lower energy positrons the pulsar would be expected to generate, based on models. Case weakens for antimatter sign of dark matter 2017-03-06T05:00:00Z The two short solenoids are used in capture and preparation of the antiproton and positron plasmas. Observation of the 1S–2S transition in trapped antihydrogen : Nature : Nature Research 2016-12-18T05:00:00Z At 1 T, the |c〉 → |b〉 and |d〉 → |a〉 transitions correspond to positron spin flips. Observation of the hyperfine spectrum of antihydrogen : Nature : Nature Research 2017-08-01T04:00:00Z It could be that the positrons come from other conventional astrophysical sources such as high-energy particles produced by black holes siphoning gas from nearby companion stars. Through a Gas, Darkly: Scientists Trace the Origins of Earth's Antimatter 2017-11-16T05:00:00Z The mutual annihilation of those particles might create a half-and-half blend of electrons and positrons in a narrow energy range. Giant space magnet may have trapped antihelium, raising idea of lingering pools of antimatter in the cosmos 2017-04-19T04:00:00Z He says the study is somewhat speculative in its modelling of the pulsars, such as how readily the lower energy positrons of interest diffuse through the halo. Case weakens for antimatter sign of dark matter 2017-03-06T05:00:00Z Potential manipulations are carefully controlled to create and maintain temperatures as low as possible for the positrons and antiprotons during mixing. Observation of the 1S–2S transition in trapped antihydrogen : Nature : Nature Research 2016-12-18T05:00:00Z The absolute energy scales for the positron and antiproton spin-flip transitions in ALPHA-2 are respectively five and eight orders of magnitude smaller than that of the laser transition that was recently observed15. Observation of the hyperfine spectrum of antihydrogen : Nature : Nature Research 2017-08-01T04:00:00Z One promising explanation: the excess could come from nearby pulsars, rapidly whirling remnants of expired massive stars that violently expel positrons and a menagerie of other high-energy particles as they spin. Through a Gas, Darkly: Scientists Trace the Origins of Earth's Antimatter 2017-11-16T05:00:00Z To Ting, the best explanation for the extra positrons is a dark matter particle with a mass of 1 teraelectronvolt—about as much energy as a flying mosquito. Giant space magnet may have trapped antihelium, raising idea of lingering pools of antimatter in the cosmos 2017-04-19T04:00:00Z Conventional astrophysical models show that the higher the positrons’ energy, the rarer they ought to be compared to the number of electrons arriving. Case weakens for antimatter sign of dark matter 2017-03-06T05:00:00Z The two short solenoids are used in capture and preparation of the antiproton and positron plasmas. Observation of the 1S–2S transition in trapped antihydrogen : Nature : Nature Research 2016-12-18T05:00:00Z The researchers compared the count between instances when the laser was tuned to the positron transition, versus times when the laser was tuned away from it, or left off. Deep probe of antimatter puts Einstein’s special relativity to the test 2016-12-19T05:00:00Z When gamma rays from annihilated positrons smash into Earth’s atmosphere, they rip apart atoms, generating showers of particles that hurtle downward at nearly the speed of light. Through a Gas, Darkly: Scientists Trace the Origins of Earth's Antimatter 2017-11-16T05:00:00Z They measured the frequency of light needed to jolt a positron — an antielectron — from its lowest energy level to the next level up, and found no discrepancy with the corresponding energy transition in ordinary hydrogen. Ephemeral antimatter atoms pinned down in milestone laser test 2016-12-18T05:00:00Z Their conclusion: Pulsars are “very likely” responsible for “much, if not the entirety” of the observed positron excess. Case weakens for antimatter sign of dark matter 2017-03-06T05:00:00Z The antihydrogen production method involves a new technique in which we ‘stack’ anti-atoms resulting from two successive mixing cycles, which originate from independent shots of antiprotons from the antiproton decelerator and accumulations of positrons. Observation of the 1S–2S transition in trapped antihydrogen : Nature : Nature Research 2016-12-18T05:00:00Z He helped establish multiple organ transplant programs, a comprehensive cancer center and one of the first federally funded centers for research in positron emission tomography, or PET scans. Longtime UCLA medical school dean Sherman Mellinkoff dies at 96 2016-07-25T04:00:00Z Even so, the positron excess remains “one of the most exciting mysteries in astrophysics,” says Justin Vandenbroucke, a particle astrophysicist at the University of Wisconsin–Madison, also unaffiliated with the work. Through a Gas, Darkly: Scientists Trace the Origins of Earth's Antimatter 2017-11-16T05:00:00Z He helped establish multiple organ transplant programs, a comprehensive cancer center and one of the first federally funded centers for research in positron emission tomography, or PET scans. Longtime UCLA med school dean Sherman Mellinkoff dies at 96 2016-07-25T04:00:00Z The energy of the positrons and electrons making these gamma rays would be far too high—at tens of thousands of GeV rather than a few hundred GeV—to explain the rise seen by AMS. Case weakens for antimatter sign of dark matter 2017-03-06T05:00:00Z The researchers used positron emission tomography, which are also called PET scans, to look at amyloid deposition in the brains of 68 women between the ages of 42 to 59. Health Buzz: Estrogen Patch Could Reduce Alzheimer’s Risk 2016-07-13T04:00:00Z Simulated antiatoms are launched from a volume corresponding to the precursor positrons. An improved limit on the charge of antihydrogen from stochastic acceleration : Nature : Nature Publishing Group 2016-01-19T05:00:00Z In the 1990s, groups in North America, Japan, and Europe independently started planning linear colliders to smash together electrons and antielectrons, or positrons. Japan hopes to staff up to host the International Linear Collider 2016-01-07T05:00:00Z In 2013, AMS scientists reported measuring numbers and energies of positrons that hinted at, but did not confirm, the existence of dark matter. Dark-Matter Experiment on Space Station Hits a Glitch 2015-09-02T04:00:00Z Surfing Antimatter: Accelerating positrons with plasma is a step toward smaller, cheaper particle colliders. Physics Week in Review: August 29, 2015 2015-08-29T04:00:00Z Hogan said he underwent a CT scan, which shows the size of tumors, and a positron emission tomography — or PET — scan, which shows whether there are active or dead cells. Hogan making progress against cancer but isn’t in the clear, experts say 2015-08-19T04:00:00Z During this relaxation/randomization phase, electric fields are applied that clear the positrons and antiprotons remaining in the trap. An improved limit on the charge of antihydrogen from stochastic acceleration : Nature : Nature Publishing Group 2016-01-19T05:00:00Z Instead, positrons induce the radioactive tracer molecules to emit gamma rays, and it is those that are detected and used to chart brain function. Louis Sokoloff, NIH scientist who created technique to detect and treat major brain disorders, dies at 93 2015-08-03T04:00:00Z The Herald-Tribune reports Andres Avalos appeared in court Thursday for a status conference in which assistant public defender Franklin Roberts asked that his client be granted transportation for a positron emission tomography, or PET scan. Man accused of killing 3 will have brain scan prior to trial 2015-05-17T04:00:00Z The positron then shoots off so fast that it creates a flash of Cherenkov radiation. The watcher in the water 2015-05-14T04:00:00Z In particular, he says, the team’s estimate of the size of the positron cloud is not convincing. Rogue antimatter found in thunderclouds 2015-05-11T04:00:00Z In the experiment, we mix positrons and antiprotons for 1 s. An improved limit on the charge of antihydrogen from stochastic acceleration : Nature : Nature Publishing Group 2016-01-19T05:00:00Z Positrons give their name to the method of positron emission tomography. Louis Sokoloff, NIH scientist who created technique to detect and treat major brain disorders, dies at 93 2015-08-03T04:00:00Z When cosmic rays smash into molecules in our atmosphere, the collisions create showers of subatomic particles, including electrons, positrons, and other electrically charged particles. Cosmic rays could reveal secrets of lightning on Earth 2015-04-23T04:00:00Z The players were given PET, or positron emission tomography, scans that revealed tau protein deposits in their brains, a signature of C.T.E. Progress Is Seen in Detecting C.T.E. in Living Patients 2015-04-06T04:00:00Z “We tried for five years to model the production of the positrons,” says Dwyer. Rogue antimatter found in thunderclouds 2015-05-11T04:00:00Z The hospital’s diagnostic imaging department offers services in cardiology, CT, nuclear medicine, radiology and positron emission tomography, or PET, scans, mammography, ultrasound, MRI and bone density testing. Emphasis on enhancing patient care? 2015-03-09T04:00:00Z Wong exclaimed, correctly identifying Brefczynski-Lewis’s project, which involves the creation of a portable positron emission tomography scan capable of imaging activity in deep brain structures as a person moves, talks or performs a task. Brainstormers: Obama’s big research push kicks off with a meeting of the minds 2015-01-02T05:00:00Z Therefore, to keep my second resolution, I am going to explore topics beyond chemistry, such as synchrotron radiation and positron annihilation. Leadership: New year's resolutions 2014-12-29T05:00:00Z The dark-matter riddle relates to an unexpected excess of positrons — the antimatter partners of electrons — among cosmic rays, highly energetic particles swirling around the galaxy. European probe shoots down dark-matter claims 2014-12-01T05:00:00Z Such models were invented to explain an excess of high positrons seen by detectors such as the Alpha Magnetic Spectrometer aboard the International Space Station. Study of big bang’s afterglow sheds light on evolution of universe 2014-12-01T05:00:00Z Revving up positrons is "about a factor of 10 times more difficult" than accelerating electrons, Downer estimates. Physicists crank up current in new type of accelerator 2014-11-07T05:00:00Z The Spear machine started up in 1973, colliding electrons and their antimatter opposites, positrons, to produce tiny fireballs. Martin Perl, Physicist Who Discovered Electron’s Long-Lost Brother, Dies at 87 2014-10-03T04:00:00Z Instead, they smash into an air molecule high in the atmosphere, producing a blast of photons, electrons, positrons, muons and other collision products that then slam into other air molecules. Astronomy: To catch a cosmic ray 2014-09-30T04:00:00Z But observations from the Alpha Magnetic Spectrometer, a particle detector on the International Space Station, revealed last year that the ratio of positrons to electrons actually increases with energy1. European probe shoots down dark-matter claims 2014-12-01T05:00:00Z One possible explanation is that these excess positrons are a by-product of dark matter interactions. Dark Matter Looks WIMPy 2014-09-24T04:00:00Z The controversy centers on AMS's measurement of a key ratio, the number of antimatter positrons to the sum of positrons and electrons. Space station detector reports more hints of dark matter—or not 2014-09-19T04:00:00Z Lower-energy electron–positron machines produce cleaner collisions that are easier to analyse, because they are already smashing together fundamental particles. China plans super collider 2014-07-21T04:00:00Z Several locations could now enter a race to convert photons into positrons and electrons for the very first time. New design to turn light into matter 2014-05-19T04:00:00Z Theory predicts that at high energies, the ratio of positrons to electrons ought to be lower than it is at lower energies. European probe shoots down dark-matter claims 2014-12-01T05:00:00Z Normal astrophysical processes create some positrons, but not as many as AMS registered. Dark Matter Looks WIMPy 2014-09-24T04:00:00Z That would alter the balance of electrons and positrons among cosmic rays, as the usual source such as the cloudlike remnants of supernova explosions produce far more electrons than positrons. Space station detector reports more hints of dark matter—or not 2014-09-19T04:00:00Z China would like to build its electron–positron collider in the meantime, unaided by international funding if needs be, and follow it up as fast as technologically possible with the super proton collider. China plans super collider 2014-07-21T04:00:00Z They worked out that – very rarely – two particles of light, or photons, could combine to produce an electron and its antimatter equivalent, a positron. Matter will be created from light within a year, claim scientists 2014-05-18T04:00:00Z Researchers have suggested that the positron excess could be caused by collisions in which dark-matter particles annihilate each other and produce a shower of debris, including positrons. European probe shoots down dark-matter claims 2014-12-01T05:00:00Z Its new results show more positrons than expected. Dark Matter Looks WIMPy 2014-09-24T04:00:00Z So, in fact, the new data support the interpretation that the positrons are simply secondary cosmic rays, he says. Space station detector reports more hints of dark matter—or not 2014-09-19T04:00:00Z Electron–positron colliders and hadron colliders such as the LHC complement each other. China plans super collider 2014-07-21T04:00:00Z When the photons collide, the researchers believe that a significant number of them will turn from light to matter — more specifically, into an electron and a positron. Scientists propose collider that could turn light into matter 2014-05-18T04:00:00Z What AMS wants to do is measure exactly how does this positron fraction cut off at the highest energies. When Will We Find Dark Matter? 2014-05-16T04:00:00Z Now researchers have discovered that a particular type of brain imaging, positron emission tomography, may be able to determine which vegetative patients will recover. Study: New Technique Predicts Consciousness of Brain-Damaged Patients 2014-04-15T22:58:05Z If so, then the positrons were just "secondary" rays and nothing to write home about. Space station detector reports more hints of dark matter—or not 2014-09-19T04:00:00Z Researchers had also mapped blood flow using positron emission tomography scans, but that required making and handling radioactive trace chemicals, whose signature vanished within minutes. Jack Belliveau, Explorer of the Brain, Dies at 55 2014-03-10T03:30:43Z What Dirac had considered a positively charged hole physicists nowadays think of as a positron—an object in its own right, not merely a hole. Schrodinger’s Rats and The Search for Ultimate Reality [Excerpt] 2014-01-31T15:00:00Z Scientists tell the Guardian their favorite jokes: “An electron and a positron walked into a bar…” Physics Week in Review: January 4, 2014 2014-01-04T22:45:08.163Z AMS detected promising numbers of electrons and their anti-matter counterparts known as positrons that are thought to shower deep space as dark matter particles annihilate each other - but the evidence was not conclusive. A science news preview of 2014 2014-01-01T00:44:50Z Second, the AMS team measured the spectra of electrons and positrons individually. Space station detector reports more hints of dark matter—or not 2014-09-19T04:00:00Z Beta-amyloid in their brains was measured by positron emission tomography, or PET scans. Seniors who don’t sleep well have higher levels of an Alzheimer’s biomarker, study says 2013-10-28T20:11:11Z You can think of a positron as a thing or as an absence, two ontologies about as opposite as you can find, but from the point of view of mathematical structure, they’re exactly the same. Schrodinger’s Rats and The Search for Ultimate Reality [Excerpt] 2014-01-31T15:00:00Z They were then placed in a positron emission tomography scanner and told that the people they were interested in either were or were not interested in them. For the Pain of Rejection, Take a Tylenol? 2013-10-17T19:46:53Z The team, lead by the National Institute of Radiological Sciences in Chiba, used positron emission tomography to build a 3D picture of tau in the brain. Alzheimer's brain scan advances 2013-09-19T00:29:33Z "It's really surprising that the electrons and positrons are so different," Ting says. Space station detector reports more hints of dark matter—or not 2014-09-19T04:00:00Z Instead, positron emission tomography, known as PET scans, should be studied further and Medicare coverage extended only to older patients participating in clinical trials examining their usefulness, the federal agency recommended in a preliminary decision. The New Old Age Blog: Decision Casts Doubt on Brain Scans for Alzheimer’s 2013-08-01T09:01:40Z Antimatter is made all the time in the sun, which produces positrons as a side effect of fusing hydrogen into helium. Where Are the Anti-People? [Excerpt] 2013-07-12T16:15:05.140Z All three are radioactive tracers designed to light up deposits of an Alzheimer's-related protein called beta amyloid when used in conjunction with brain scans known as positron emission tomography, or PET. Medicare plan on Alzheimer's test dismays advocates 2013-07-09T23:35:18Z Both are radioactive tracers designed to light up deposits of an Alzheimer's-related protein called beta amyloid when used in conjunction with brain scans known as positron emission tomography, or PET. Groups dismayed by decision not to cover Alzheimer's test 2013-07-09T04:15:50Z The radioactive imaging agent works by binding to beta-amyloid plaques and causing them to show up on positron emission tomography, or PET, scans of the patient's brain. Medicare won't pay for Eli Lilly Alzheimer's agent 2013-07-08T16:31:48Z A similar trap accumulates positrons that are emitted by radioactive materials. Giant, Heavy and Hollow: Physicists Create Extreme Atoms 2013-06-06T13:15:00.177Z Just as hydrogen is made of a proton and an electron, antihydrogen is an atom made of their antimatter counterparts antiprotons and positrons. Cern closes in on antigravity answer 2013-04-30T17:38:15Z They confirm the presence of a mysterious excess of positrons, seen in our Galaxy by two earlier experiments, but fail to pin down its origin. Seven days: 5–11 April 2013 2013-04-10T17:20:19.497Z To wit: AMS detected some extra positrons that seemed to fit the energy ranges predicted by models for dark matter particles. Physics Week in Review: April 6, 2013 2013-04-06T22:15:03.053Z So is the fact that the positrons are hitting the detector from all directions, which it should if dark matter truly pervades the Milky Way. Says, Has the Missing 80% of the Universe's Mass Been Found? 2013-04-05T11:05:24Z The idea is that when WIMPs crash into each other, they annihilate and produce two particles—electrons and positrons—which are much easier to detect than the WIMPs themselves. Scientists Find Hint of Dark Matter 2013-04-03T23:25:13Z If pulsars are responsible, theory predicts that the positron fraction should decline steadily at energies above this value. Dark matter: Fractional distillation 2013-04-03T16:48:49Z The other possible origin is that positrons are emitted by rapidly rotated, ultra-dense stars called pulsars, which are scattered throughout the galaxy. Dark matter may be source of exotic space particles, physicist says 2013-04-03T17:38:52Z The findings Wednesday are based on seeing an excess of positrons — positively charged subatomic particles. Scientists find traces of dark matter from cosmos 2013-04-03T16:23:00Z Their ubiquity would send positrons to us from all directions just the way dark matter would. Has the Missing 80% of the Universe's Mass Been Found? 2013-04-05T11:05:24Z Physicists also need to ensure that the positrons they are seeing don't emanate from a pulsar, a type of star; that wouldn't be a finding about dark matter. Scientists Find Hint of Dark Matter 2013-04-03T23:25:13Z It is these high-energy electrons and positrons that AMS is on the lookout for. Dark matter: Fractional distillation 2013-04-03T16:48:49Z The disk is also designed to let positrons escape from one side, in case you want some. How to Build Your Own Quantum Entanglement Experiment (Part 1 of 2) 2013-02-08T16:45:03.680Z And his caption under this diagram is, "A positron, of course, is an electron going backward in time." Alan Alda Challenges Scientists to Explain: What Is Time? 2012-12-12T22:00:00Z Dark matter collisions, the scientists acknowledge, are not the only possible source of positrons. Has the Missing 80% of the Universe's Mass Been Found? 2013-04-05T11:05:24Z The theory predicts two outcomes: that the annihilations should produce a large number of positrons; and that after the excess, there should be a sudden decline in positron production. Scientists Find Hint of Dark Matter 2013-04-03T23:25:13Z To get round this, AMS examines how the ratio of positrons to electrons varies with the particles’ energy. Dark matter: Fractional distillation 2013-04-03T16:48:49Z Gal-Yam describes how the production of electrons and positrons removed such stars' supporting pressure of gamma rays, leading to their sudden collapse. Readers Respond to "Cyborg Humanity" 2012-09-21T18:15:00.263Z Afterward, the team showed the birds humans wearing the two different masks and monitored the crows' brain activity using positron emission tomography. ScienceShot: Bird Brains Show Their Fear of Faces 2012-09-10T20:10:00Z The number and energy of the positrons is consistent with what theorists would expect if dark matter really is smashing into itself throughout the Milky Way. Has the Missing 80% of the Universe's Mass Been Found? 2013-04-05T11:05:24Z Foster is the European regional director for the rival concept of a linear electron–positron collider. After the Higgs: The new particle landscape 2012-08-29T17:50:28.943Z When two neutralinos bump into each other, the theory goes, they should annihilate one another and produce in their stead an electron and its antimatter equivalent, a positron. Dark matter: Fractional distillation 2013-04-03T16:48:49Z But he didn't say what happens to the positrons. Readers Respond to "Cyborg Humanity" 2012-09-21T18:15:00.263Z A dark-matter particle from the dark sector — “even darker matter”, quips Arkani-Hamed — would be seen only through a decay involving the force-carrying dark photon, which would make positrons but not antiprotons. Physicists hunt for dark forces 2012-04-04T17:20:36.127Z The new study involved the use of an imaging agent known as Pittsburgh Compound B or PiB, which works with positron emission tomography, or PET scanners. Keeping brain sharp may ward off Alzheimer's protein 2012-01-23T22:20:41Z This type of machine would essentially be a long, straight electron accelerator firing right down the barrel of an equally long, straight positron accelerator, with their beams slamming together in the middle. After the Higgs: The new particle landscape 2012-08-29T17:50:28.943Z The problem is spotting them against a backdrop of electrons from other cosmic sources, which are much more common than positrons are. Dark matter: Fractional distillation 2013-04-03T16:48:49Z Last fall Fermi confirmed earlier findings that positrons are peppering our planet; these cosmic particles, the antimatter twin of electrons, might originate in the self-destruction of dark-matter particles. Magnetoastrocoolness: How Cosmic Magnetic Fields Shape Planetary Systems 2012-01-13T16:15:05.427Z Next, positron emission tomography, or PET scanning, revealed blood flow and metabolism by tracing the path of an injected radioactive chemical. What Triggers the Brain? New Technologies Aid Discovery 2011-12-07T15:30:00Z However, in that analysis, the Fermi group considered the sum total of all charged particles, electrons, and positrons. Cosmic Antimatter Excess Confirmed 2011-11-22T21:13:00Z In an antimatter world, the small things that orbit atoms would be anti-electrons, also known as positrons, and they would accelerate in the direction of the electric field, not the opposite. Galactic Challenge Part III: The "Easy" Solutions 2011-09-12T18:15:05.793Z Beyond that peak, the fraction should plummet, because few high-energy positrons from other sources would be expected to exist, whereas energetic electrons are abundant. Dark matter: Fractional distillation 2013-04-03T16:48:49Z That challenge was overcome in 2004 using positron emission tomography to identify amyloid plaques. Perspective: Prevention is better than cure 2011-07-13T17:20:58.477Z In 1936, Hess was awarded the Nobel Prize in physics for the discovery of cosmic rays, sharing the prize with Carl Anderson, the discoverer of the positron; Wulf was nowhere mentioned. Paris: City of Light and Cosmic Rays 2011-07-04T14:15:00.943Z Noting the energy level—physicists measure this in billions of electron volts—at which the positron signal drops off would allow physicists to calculate the WIMP's mass. Cosmic Antimatter Excess Confirmed 2011-11-22T21:13:00Z In medical school she read an article in Scientific American about one of the first American positron emission tomography scanners, able to photograph not only the brain’s structures but also its invisible processes. Profiles in Science: Nora D. Volkow: A General in the Drug War 2011-06-13T21:48:47Z These data show that the positron fraction does indeed rise with energy, just as theory predicts. Dark matter: Fractional distillation 2013-04-03T16:48:49Z In the anti-form, the mirror of an electron - a positron - is bound to an antiproton. Science ups the 'anti' on matter 2011-06-06T09:12:12Z When that happens, the positively charged positron and the negatively charged antiproton cancel each other's charges. Antiatoms, All Out of Energy and Ready for Work 2011-06-05T18:00:00Z That is, that the relative abundance of positrons seems to rise from 20 billion to 100 billion electron volts. Cosmic Antimatter Excess Confirmed 2011-11-22T21:13:00Z And just as the neutral hydrogen atom is made of a single proton bound to an electron, an atom of antihydrogen comprises an antiproton and a positron, the antimatter counterparts, respectively. Stick Up: Antimatter Atoms Trapped for More Than 15 Minutes 2011-06-05T17:15:00.427Z If neutralinos are responsible, though, at some point—corresponding to the energy equivalent of their mass—the positron fraction will fall off a cliff. Dark matter: Fractional distillation 2013-04-03T16:48:49Z Their wearable "Ratcap" does positron emission tomography - an established technique that tracks the movement and change of an injected molecule. Wearable scanner maps rat brains 2011-03-14T11:56:34Z Luc De Nil, of the University of Toronto, has been poring over stutterers’ brains using positron emission tomography and functional magnetic resonance imaging. The science of stuttering: Speech therapy 2011-02-24T10:45:13Z Theorists generally believe that when two dark matter particles collide, they should annihilate each other to produce ordinary particles, such as an electron and its antimatter twin, a positron. Cosmic Antimatter Excess Confirmed 2011-11-22T21:13:00Z The randomized study, conducted in 2009, asked 47 participants to undergo positron emission tomography, or PET, scans, a type of scan used to measure brain glucose metabolism, a marker of brain activity. Well: Cellphone Use Tied to Changes in Brain Activity 2011-02-22T21:31:34Z It is approved for viewing and making diagnoses from many types of scans including magnetic resonance imaging, computed tomography or CT and the nuclear medicine test called positron emission tomography or PET. New app lets docs use cellphones to examine imaging scans 2011-02-17T21:37:04Z Amyvid, known generically as florbetapir, is an imaging agent injected into patients who are then put through a positron emission tomography, or PET, scan to detect the plaque. F.D.A. Sees Promise in Alzheimer?s Imaging Drug 2011-01-20T23:03:01Z "But what absolutely intrigues us is the discovery that TGFs produce not just gamma rays but also produce positrons, the antimatter equivalent to electrons." Antimatter 'streams from storms' 2011-01-11T08:34:33Z However, because positrons are produced elsewhere in the universe, including in pulsars and neutron stars, the result was inconclusive at best—although it stirred quite a frenzy. Cosmic Antimatter Excess Confirmed 2011-11-22T21:13:00Z Both it and SuperB will increase production of B-meson and other particles by hugely compessing the beams of electrons and positrons in a scheme developed by the SuperB team. Italy Funds New Particle Smasher With U.S. Components 2010-12-24T09:14:44Z Two years ago a European satellite named Pamela registered an excess of anti-electrons, or positrons, in space — perhaps from collisions of dark matter particles. A Costly Quest for the Dark Heart of the Cosmos 2010-11-17T11:38:00Z The positrons, produced by the decay of radioactive sodium, are cooled into a similarly sized cloud of around 1m particles and held in a neighbouring trap. Antimatter: Gotcha! 2010-11-18T11:27:00Z Many brain imaging studies, using positron emission tomography, show that cues like viewing drug paraphernalia are enough by themselves to activate memory circuits and unleash drug craving. Mind: Lasting Pleasures, Robbed by Drug Abuse 2010-08-30T20:16:00Z The expected signal would be a steady rise of positrons over a given range of energies, followed by a sudden drop-off. Cosmic Antimatter Excess Confirmed 2011-11-22T21:13:00Z The team tested 238 young rhesus monkeys using a high-resolution type of positron emission tomography or PET scan. Nervous monkeys lend clues to childhood anxiety 2010-08-11T22:36:00Z But that satellite had no way to tell positrons, which are exotic, from protons, which are humdrum, being the nuclei of hydrogen, and everywhere. A Costly Quest for the Dark Heart of the Cosmos 2010-11-17T11:38:00Z The antiprotons are then pushed into the same trap as the positrons and left to mingle for a second or so. Antimatter: Gotcha! 2010-11-18T11:27:00Z The investigations found that the center — regarded by experts as the nation’s leader in the use of positron emission tomography, or PET, for psychiatric research — repeatedly violated regulations over a four-year period. Brain Center at Columbia Gave Patients Impure Drugs 2010-07-17T03:40:00Z All three of the imaging tests are designed to cause beta amyloid clumps to light up when patients' brains are scanned using PET, or positron emission tomography. Study finds brain dye can detect Alzheimer's 2010-07-13T00:07:00Z And they did an imaging test called positron emission tomography or PET to test for brain function by looking to see how well the brain uses glucose or sugar. Study identifies best tests to predict Alzheimer's 2010-06-30T22:52:00Z According to some physicists, including Dr. Ellis and Dr. Ting, the positrons from dark matter should have a unique spectral signature that the cosmic ray spectrometer can measure. A Costly Quest for the Dark Heart of the Cosmos 2010-11-17T11:38:00Z Imaging tools commonly used to detect breast cancer include PET/CT, a combination of positron emission tomography and a CT scan, chest X-rays, bone scans, and ultrasound of the abdomen and pelvis. MRI scans accurately spot spread of cancer: study 2010-05-06T22:07:00Z They said the use of positron emission tomography or PET scans, which show both anatomy and organ function, grew the fastest. Cost of imaging cancer patients rising sharply 2010-04-27T20:26:00Z The collision causes the gamma ray to splinter into an electron and a positron. Cosmic Magnetic Field Strength Measured 2010-04-02T14:39:00Z These units are the positron, the negatron, and the neutron. Cube Root of Conquest Only the polarity of the positron saved me. Joy Ride Past Sulfur 32, there was a lot of positron emission as the nuclei fought to increase the number of neutrons to maintain a stable balance. The Bramble Bush I could say psi was a flow of positrons, and it would mean as much. Sense from Thought Divide The atoms just turned themselves inside out, so to speak, giving us an atom with positrons circling a negatively charged nucleus. Islands of Space With them, you produce negamatter—atoms with negatively charged protons and positive electrons, positrons. The Cosmic Computer We started, six years ago, with the ability to produce negative protons, reverse-spin neutrons, and positrons, and the theoretical possibility of assembling them into negamatter. The Answer When two nuclei of the resulting Xenon 128 are forced together, the positron emission begins long before the coalescence is complete, resulting in Fermium 256. The Bramble Bush You say you had to assemble it, after creating the negative protons and neutrons and the positrons. The Answer The only thing I can think of that would produce an effect like that is a stream of positrons—or contraterrene nuclei. Islands of Space |
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