acceleration nation

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Muon magnet’s moment has arrived

What do you get when you revive a beautiful 20-year-old physics machine, carefully transport it 3,200 miles over land and sea to its new home and then use it to probe strange happenings in a magnetic field? Hopefully you get new insights into the elementary particles that make up everything. The Muon g-2 experiment, located at the U.S. Department of Energy’s Fermi National Accelerator Laboratory, has begun its quest for those insights. On May 31, the 50-foot-wide superconducting electromagnet at the center of the experiment saw its first beam of muon particles from Fermilab’s accelerators, kicking off a three-year effort to measure just what happens to those particles when placed in a stunningly precise magnetic field. The answer could rewrite scientists’ picture of the universe and how it works. Image credit: Fermilab

Origin of Milky Way's hypothetical dark matter signal may not be so dark

A mysterious gamma-ray glow at the center of the Milky Way is most likely caused by pulsars – the incredibly dense, rapidly spinning cores of collapsed ancient stars that were up to 30 times more massive than the sun. That’s the conclusion of a new analysis by an international team of astrophysicists, including researchers from the Department of Energy’s SLAC National Accelerator Laboratory. The findings cast doubt on previous interpretations of the signal as a potential sign of dark matter – a form of matter that accounts for 85 percent of all matter in the universe but that so far has evaded detection.

“Our study shows that we don’t need dark matter to understand the gamma-ray emissions of our galaxy,” said Mattia Di Mauro from the Kavli Institute for Particle Astrophysics and Cosmology (KIPAC), a joint institute of Stanford University and SLAC. “Instead, we have identified a population of pulsars in the region around the galactic center, which sheds new light on the formation history of the Milky Way.”

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Sterile neutrino search hits roadblock at reactors


by Kathryn Jepsen

A new result from the Daya Bay collaboration reveals both limitations and strengths of experiments studying antineutrinos at nuclear reactors.

As nuclear reactors burn through fuel, they produce a steady flow of particles called neutrinos. Neutrinos interact so rarely with other matter that they can flow past the steel and concrete of a power plant’s containment structures and keep on moving through anything else that gets in their way.

Physicists interested in studying these wandering particles have taken advantage of this fact by installing neutrino detectors nearby. A recent result using some of these detectors demonstrated both their limitations and strengths.

The reactor antineutrino anomaly

In 2011, a group of theorists noticed that several reactor-based neutrino experiments had been publishing the same, surprising result: They weren’t detecting as many neutrinos as they thought they would.

Or rather, to be technically correct, they weren’t seeing as many antineutrinos as they thought they would; nuclear reactors actually produce the antimatter partners of the elusive particles. About 6 percent of the expected antineutrinos just weren’t showing up. They called it “the reactor antineutrino anomaly.”

The case of the missing neutrinos was a familiar one. In the 1960s, the Davis experiment located in Homestake Mine in South Dakota reported a shortage of neutrinos coming from processes in the sun. Other experiments confirmed the finding. In 2001, the Sudbury Neutrino Observatory in Ontario demonstrated that the missing neutrinos weren’t missing at all; they had only undergone a bit of a costume change.

Neutrinos come in three types. Scientists discovered that neutrinos could transform from one type to another. The missing neutrinos had changed into a different type of neutrino that the Davis experiment couldn’t detect.
Since 2011, scientists have wondered whether the reactor antineutrino anomaly was a sign of an undiscovered type of neutrino, one that was even harder to detect, called a sterile neutrino.

A new result from the Daya Bay experiment in China not only casts doubt on that theory, it also casts doubt on the idea that scientists understand their model of reactor processes well enough at this time to use it to search for sterile neutrinos.

The word from Daya Bay

The Daya Bay experiment studies antineutrinos coming from six nuclear reactors on the southern coast of China, about 35 miles northeast of Hong Kong. The reactors are powered by the fission of uranium. Over time, the amount of uranium inside the reactor decreases while the amount of plutonium increases. The fuel is changed—or cycled—about every 18 months.
The main goal of the Daya Bay experiment was to look for the rarest of the known neutrino oscillations. It did that, making a groundbreaking discovery after just nine weeks of data-taking.

But that wasn’t the only goal of the experiment. “We realized right from the beginning that it is important for Daya Bay to address as many interesting physics problems as possible,” says Daya Bay co-spokesperson Kam-Biu Luk of the University of California, Berkeley and the US Department of Energy’s Lawrence Berkeley National Laboratory.

For this result, Daya Bay scientists took advantage of their enormous collection of antineutrino data to expand their investigation to the reactor antineutrino anomaly.

Using data from more than 2 million antineutrino interactions and information about when the power plants refreshed the uranium in each reactor, Daya Bay physicists compared the measurements of antineutrinos coming from different parts of the fuel cycle: early ones dominated by uranium through later ones dominated by both uranium and plutonium.

In theory, the type of fuel producing the antineutrinos should not affect the rate at which they transform into sterile neutrinos. According to Bob Svoboda, chair of the Department of Physics at the University of California, Davis, “a neutrino wouldn’t care how it got made.” But Daya Bay scientists found that the shortage of antineutrinos existed only in processes dominated by uranium.

Their conclusion is that, once again, the missing neutrinos aren’t actually missing. This time, the problem of the missing antineutrinos seems to stem from our understanding of how uranium burns in nuclear power plants. The predictions for how many antineutrinos the scientists should detect may have been overestimated.

“Most of the problem appears to come from the uranium-235 model (uranium-235 is a fissile isotope of uranium), not from the neutrinos themselves,” Svoboda says. “We don’t fully understand uranium, so we have to take any anomaly we measured with a grain of salt.”

This knock against the reactor antineutrino anomaly does not disprove the existence of sterile neutrinos. Other, non-reactor experiments have seen different possible signs of their influence. But it does put a damper on the only evidence of sterile neutrinos to have come from reactor experiments so far.

Other reactor neutrino experiments, such as NEOS in South Korea and PROSPECT in the United States will fill in some missing details. NEOS scientists directly measured antineutrinos coming from reactors in the Hanbit nuclear power complex using a detector placed about 80 feet away, a distance some scientists believe is optimal for detecting sterile neutrinos should they exist.

PROSPECT scientists will make the first precision measurement of antineutrinos coming from a highly enriched uranium core, one that does not produce plutonium as it burns.

A silver lining

The Daya Bay result offers the most detailed demonstration yet of scientists’ ability to use neutrino detectors to peer inside running nuclear reactors.

“As a study of reactors, this is a tour de force,” says theorist Alexander Friedland of SLAC National Accelerator Laboratory. “This is an explicit demonstration that the composition of the reactor fuel has an impact on the neutrinos.”

Some scientists are interested in monitoring nuclear power plants to find out if nuclear fuel is being diverted to build nuclear weapons.

“Suppose I declare my reactor produces 100 kilograms of plutonium per year,” says Adam Bernstein of Lawrence Livermore National Laboratory. “Then I operate it in a slightly different way, and at the end of the year I have 120 kilograms.” That 20-kilogram surplus, left unmeasured, could potentially be moved into a weapons program.

Current monitoring techniques involve checking what goes into a nuclear power plant before the fuel cycle begins and then checking what comes out after it ends. In the meantime, what happens inside is a mystery.

Neutrino detectors allow scientists to understand what’s going on in a nuclear reactor in real time.

Scientists have known for decades that neutrino detectors could be useful for nuclear nonproliferation purposes. Scientists studying neutrinos at the Rovno Nuclear Power Plant in Ukraine first demonstrated that neutrino detectors could differentiate between uranium and plutonium fuel.

Most of the experiments have done this by looking at changes in the aggregate number of antineutrinos coming from a detector. Daya Bay showed that neutrino detectors could track the plutonium inventory in nuclear fuel by studying the energy spectrum of antineutrinos produced.

“The most likely use of neutrino detectors in the near future is in so-called ‘cooperative agreements,’ where a $20-million-scale neutrino detector is installed in the vicinity of a reactor site as part of a treaty,” Svoboda says.

“The site can be monitored very reliably without having to make intrusive inspections that bring up issues of national sovereignty.”

Luk says he is dubious that the idea will take off, but he agrees that Daya Bay has shown that neutrino detectors can give an incredibly precise report. “This result is the best demonstration so far of using a neutrino detector to probe the heartbeat of a nuclear reactor.”

Black Inventors Day 2

Shirley Ann Jackson - Dr. Shirley Jackson was the first black female to receive a doctorate from the Massachusetts Institute of Technology (MIT), and is the first black female president of a major technological institute (Rensselaer Polytechnic Institute). However, she also has a staggering list of inventions to her credit. Her experiments with theoretical physics are responsible for many telecommunications developments including the touch tone telephone, the portable fax, caller ID, call waiting, and the fiber optic cables that make overseas phone calls crystal clear.

As a postdoctoral researcher of subatomic particles during the 1970s, Jackson studied and conducted research at a number of prestigious physics laboratories in both the United States and Europe. Her first position was as research associate at the Fermi National Accelerator Laboratory in Batavia, Illinois (known as Fermilab) where she studied hadrons. In 1974 she became visiting scientist at the European Organization for Nuclear Research (CERN) in Switzerland. There she explored theories of strongly interacting elementary particles. In 1976 and 1977, she both lectured in physics at the Stanford Linear Accelerator Center and became a visiting scientist at the Aspen Center for Physics.

At one time her research focused on Landau–Ginsburg theories of charge density waves in layered compounds, and has studied two-dimensional Yang-Mills gauge theories and neutrino reactions.

Jackson joined the Theoretical Physics Research Department at AT&T Bell Laboratories in 1976, examining the fundamental properties of various materials. In 1978, Jackson became part of the Scattering and Low Energy Physics Research Department, and in 1988 she moved to the Solid State and Quantum Physics Research Department. At Bell Labs, Jackson researched the optical and electronic properties of two-dimensional and quasi-two dimensional systems. In her research, Jackson has made contributions to the knowledge of charged density waves in layered compounds, polaronic aspects of electrons in the surface of liquid helium films, and optical and electronic properties of semiconductor strained-layer superlattices. On these topics and others she has prepared or collaborated on over 100 scientific articles.

Construction Starts for Camera That Will Capture More Galaxies Than There Are People on Earth

Beginning in 2022, the most powerful digital camera ever built will start taking pictures of the southern sky. Over the course of a 10-year mission atop a mountain in Chile, the 3.2 gigapixel instrument is expected to accomplish a feat that might be hard to wrap your mind around. It will record tens of billions of galaxies floating in space–the first time a telescope will have ever identified more of the massive celestial objects than there are people on Earth.

Late last month, the U.S. Department of Energy gave its blessing for researchers to start building the camera that will sit at the heart of the Large Synoptic Survey Telescope (LSST). The gif above shows the three-ton, small-car-sized camera on the left. Illustrated is the system that slides filters down in front of the 3.2 gigapixel CCD, which senses light and is a digital camera’s version of film. The filters will let the camera record in light wavelengths from the near-ultraviolet to the near-infrared. Learn more and see images below.

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Two Amazing Pioneering Black Women Who Made Great Contributions In the Scientific Field of Physics

Willie Hobbs Moore (1934-1994)- (pictured above) was the first African-American woman to earn a Ph.D. in physics.

A native of Atlantic City, New Jersey, Moore moved to Ann Arbor, Michigan, in 1952 to attend the University of Michigan. She earned a bachelor’s degree in electrical engineering from the University of Michigan in 1958 and her master’s degree in 1961.[2] While working toward her doctoral degree, she also held positions at technology firms in Ann Arbor including KMS Industries and Datamax Corporation.[3] She also held engineering positions at Bendix Aerospace Systems, Barnes Engineering, and Sensor Dynamics, where she was responsible for the theoretical analysis.[4] Moore completed her thesis, A Vibrational Analysis of Secondary Chlorides, under the supervision of Samuel Krimm at the University of Michigan in 1972.[5] This work was applicable to important questions in the vibrational study of macromolecules.[1]

After receiving her doctorate, Moore worked at the University of Michigan as a research scientist until 1977, continuing spectroscopic work on proteins. In the five years following her dissertation, she published more than thirty papers with Krimm and collaborators.[5] She was hired by Ford Motor Company in 1977 as an assembly engineer.[6] Moore expanded Ford’s use of Japanese engineering and manufacturing methods in the 1980s.[7][8] In 1991, Ebony magazine named Moore as one of their 100 “most promising black women in corporate America.”

Moore was a tutor, a member of Links Inc., a member of the Bethel African Methodist Episcopal Church, and the chairwoman of the Juanita D. Woods Scholarship Fund. She was married to Sidney L. Moore, who taught at the University of Michigan’s Neuropsychiatric Institute, for thirty years. They had two children Dr. Dorian Moore, MD. and Christopher Hobbs Moore, RN. Willie also had three grandchildren Sydney Padgett, William Hobbs Moore, and C. Jackson Moore [3]

Moore died of cancer in 1994.

Source: Wikipedia

Shirley Ann Jackson (August 5, 1946)- (pictured below Mrs. Moore) is an American physicist and the eighteenth president of the Rensselaer Polytechnic Institute. She received herPh.D. in nuclear physics at the Massachusetts Institute of Technology in 1973, becoming the first African-American woman to earn a doctorate at MIT

Jackson was born in Washington D.C. Her parents, Beatrice and George Jackson, strongly valued education and encouraged her in school.[5] Her father spurred on her interest in science by helping her with projects for her science classes. At Roosevelt High School, Jackson attended accelerated programs in both math and science and graduated in 1964 as valedictorian. [5]

Jackson began classes at MIT in 1964, one of fewer than twenty African American students and the only one studying theoretical physics. While a student she did volunteer work at Boston City Hospital and tutored students at the Roxbury YMCA.[5] She earned her bachelor’s degree in 1968, writing her thesis on solid-state physics.

Jackson elected to stay at MIT for her doctoral work, in part to encourage more African-American students to attend the institution.[5] She worked on elementary particle theory for her Ph.D., which she completed in 1973, the first African-American woman to earn a doctorate degree from MIT. Her research was directed by James Young.[5] Jackson was also the second African-American woman in the United States to earn a doctorate in physics

As a postdoctoral researcher of subatomic particles during the 1970s, Jackson studied and conducted research at a number of prestigious physics laboratories in both the United States and Europe. Her first position was as a research associate at the Fermi National Accelerator Laboratory in Batavia, Illinois (known as Fermilab) where she studied hadrons. In 1974, she became visiting scientist at the European Organization for Nuclear Research (CERN) in Switzerland. There she explored theories of strongly interacting elementary particles. In 1976 and 1977, she both lectured in physics at the Stanford Linear Accelerator Center and became a visiting scientist at the Aspen Center for Physics.

At one time her research focused on Landau–Ginsburg theories of charge density waves in layered compounds, and has studied two-dimensional Yang-Mills gauge theories and neutrino reactions.

Jackson has described her interests:

I am interested in the electronic, optical, magnetic, and transport properties of novel semiconductor systems. Of special interest are the behavior of magnetic polarons in semimagnetic and dilute magnetic semiconductors, and the optical response properties of semiconductor quantum wells and superlattices. My interests also include quantum dots, mesoscopic systems, and the role of antiferromagnetic fluctuations in correlated 2D electron systems.[5]

Jackson joined the Theoretical Physics Research Department at AT&T Bell Laboratories in 1976, examining the fundamental properties of various materials. She began her time at Bell Labs by studying materials to be used in the semiconductor industry.[7] In 1978, Jackson became part of the Scattering and Low Energy Physics Research Department, and in 1988 she moved to the Solid State and Quantum Physics Research Department. At Bell Labs, Jackson researched the optical and electronic properties of two-dimensional and quasi-two-dimensional systems. In her research, Jackson has made contributions to the knowledge of charged density waves in layered compounds, polaronic aspects of electrons in the surface of liquid helium films, and optical and electronic properties of semiconductor strained-layer superlattices. On these topics and others, she has prepared or collaborated on over 100 scientific articles.[5]

Jackson served on the faculty at Rutgers University in Piscataway and New Brunswick, New Jersey from 1991 to 1995, in addition to continuing to consult with Bell Labs on semiconductor theory. Her research during this time focused on the electronic and optical properties of two-dimensional systems.

In 1995, President Bill Clinton appointed Jackson to serve as Chairman of the U.S. Nuclear Regulatory Commission (NRC), becoming the first woman and first African-American to hold that position.[4] At the NRC, she had “ultimate authority for all NRC functions pertaining to an emergency involving an NRC licensee.

On July 1st, 1999, Jackson became the 18th president of Rensselaer Polytechnic Institute. She was the first woman and first African-American to hold this position. Since her appointment to president of RPI, Jackson has helped raise over $1 billion in donations for philanthropic causes.[8] Jackson is leading a strategic initiative called The Rensselaer Plan and much progress has been made towards achieving the Plan’s goals. She has overseen a large capital improvement campaign, including the construction of an Experimental Media and Performing Arts Center and the East Campus Athletic Village. She enjoys the ongoing support of the RPI Board of Trustees. On April 26, 2006, the faculty of RPI (including a number of retirees) voted 155 to 149 against a vote of no-confidence in Jackson.[9] In the Fall of 2007, the Rensselaer Board of Trustees suspended the faculty senate, thus prompting a strong reaction from the Rensselaer community that resulted in various protests including a "teach-in”.[10][11]

Since arriving at RPI, Jackson has been one of the highest-paid university presidents in the nation.[12] Her combined salary and benefits have expanded from $423,150 in 1999-2000 to over $1.3 million in 2006-07 and to $2.34 million in 2010.[13][14] In 2011 Jackson’s salary was $1.75 million.[15] In 2006-07, it is estimated she received another $1.3 million from board seats at several major corporations.[13] The announcement of layoffs at RPI in Decembe 2008 led some in the RPI community to question whether the institute should continue to compensate Jackson at this level, maintain a $450,000 Adirondack residence for her, and continue to support a personal staff of housekeepers, bodyguards and other aides.[13] In July 2009, the news reported on the construction of a 10,000-square-foot (930 m2) mountain-top home in Bolton, New York, overlooking Lake George. A water-quality activist raised concerns about possible environmental hazards from the construction of a driveway, but according to Department of Environmental Conservation officials, the work was in compliance.[16]

In its 2009 review of the decade 1999-2009, McClatchy Newspapers reported Jackson as the highest-paid currently sitting college president in the U.S., with a 2008 salary of approximately $1.6 million.[17] On December 4–5, 2009 Jackson celebrated her 10th year at RPI with an extravagant “Celebration Weekend”, which featured tribute concerts by Aretha Franklin and Joshua Bell among other events.[18][19] Following the weekend, the Board of Trustees announced they would support construction of a new guest house on Jackson’s property, for the purpose of “[enabling] the president to receive and entertain, appropriately, Rensselaer constituents, donors, and other high-level visitors”.[20] It was later reported that Jackson’s current house on Tibbits Avenue has 4,884 square feet (453.7 m2) of space, seven bedrooms and five bathrooms, and an estimated value of $1,122,500.[21] The trustees said that “the funds for this new project would not have been available for any other purpose”.[20] William Walker, the school’s vice president of strategic communications and external relations noted, “The board sees this very much as a long-term investment … for President Jackson and her successors.”[21] On February 2, 2010, the Troy Zoning Board of Appeals denied RPI’s request for a zoning variance allowing them to construct the new house at a height of 44 feet (13 m), which would exceed the 25-foot (7.6 m) height restriction on buildings in residential areas. The Zoning Board stated that it is “too big”, and two firefighters believed the property would be difficult to access with emergency vehicles.[22] A new plan was announced on February 25, describing how the president’s house will be replaced with a new two-story house.[23] The new house will have “9,600 square feet of livable space, divided approximately equally between living space for the president’s family and rooms for the president to conduct meetings and events”.[24] In June 2010, it was discovered that the newest plans for the house showed a new size of 19,500 square feet (1,810 m2), causing the city of Troy to issue a stop-work order until additional building fees were paid.[25] Jackson’s development and implementation of the Rensselaer Plan enabled her to secure a $360 million unrestricted gift commitment to the university.[26]

In June 2010, it was announced that the Rensselaer Board of Trustees unanimously voted to extend Jackson a ten-year contract renewal, which she accepted.[27] Shirley Ann Jackson’s compensation ranked 1st among USA private university presidents in 2014.

Jackson has received many fellowships, including the Martin Marietta Aircraft Company Scholarship and Fellowship, the Prince Hall Masons Scholarship, the National Science Foundation Traineeship, and a Ford Foundation Advanced Study Fellowship. She has been elected to numerous special societies, including the American Physical Society and American Philosophical Society.[29]

Her achievements in science and education have been recognized with multiple awards, including the CIBA-GEIGY Exceptional Black Scientist Award. In the early 1990s, Governor James Florio awarded her the Thomas Alva Edison Science Award for her contributions to physics and for the promotion of science. In 2001, she received the Richtmyer Memorial Award given annually by the American Association of Physics Teachers. She has also received many honorary doctorate degrees.[30]

She was inducted into National Women’s Hall of Fame in 1998 for “her significant contributions as a distinguished scientist and advocate for education, science, and public policy”.[citation needed]

Jackson has also been active in professional associations and in serving society through public scientific commissions. In 1985, Governor Thomas Kean appointed her to the New Jersey Commission on Science and Technology. She is an active voice in numerous committees of the National Academy of Sciences, the American Association for the Advancement of Science (AAAS), and the National Science Foundation. Her continuing aim has been to preserve and strengthen the U.S. national capacity for innovation by increasing support for basic research in science and engineering. This is done in part by attracting talent from abroad and by expanding the domestic talent pool by attracting women and members of under-represented groups into careers in science. In 2004, she became president of the American Association for the Advancement of Science and chaired the AAAS board in 2005.

In spring 2007, she was awarded the Vannevar Bush Award for “a lifetime of achievements in scientific research, education and senior statesman-like contributions to public policy”.[31]

Jackson continues to be involved in politics and public policy. In 2008, she became the University Vice Chairman of the U.S. Council on Competitiveness, a not-for-profit group based in Washington, D.C. In 2009, President Barack Obama appointed Jackson to serve on the President’s Council of Advisors on Science and Technology, a 20-member advisory group dedicated to public policy.[32]

She was appointed an International Fellow[2] of the Royal Academy of Engineering[2] in 2012.

Jackson serves on the boards of directors of many organizations:[3]

Shirley Jackson is married to Morris A. Washington, a physics professor at Rensselaer Polytechnic Institute, and has one son, Alan, a Dartmouth College alumnus.

Source: Wikipedia

Symmetry Magazine

Muon magnet’s moment has arrived


By Andre Salles

The Muon g-2 experiment has begun its search for phantom particles with its well-traveled electromagnet.

What do you get when you revive a beautiful 20-year-old physics machine, carefully transport it 3200 miles over land and sea to its new home, and then use it to probe strange happenings in a magnetic field? Hopefully you get new insights into the elementary particles that make up everything.

The Muon g-2 experiment, located at the US Department of Energy’s Fermi National Accelerator Laboratory, has begun its quest for those insights.
On May 31, the 50-foot-wide superconducting electromagnet at the center of the experiment saw its first beam of muon particles from Fermilab’s accelerators, kicking off a three-year effort to measure just what happens to those particles when placed in a stunningly precise magnetic field. The answer could rewrite scientists’ picture of the universe and how it works.

“The Muon g-2 experiment’s first beam truly signals the start of an important new research program at Fermilab, one that uses muon particles to look for rare and fascinating anomalies in nature,” says Fermilab Director Nigel Lockyer. “After years of preparation, I’m excited to see this experiment begin its search in earnest.”

Getting to this point was a long road for Muon g-2, both figuratively and literally. The first generation of this experiment took place at Brookhaven National Laboratory in New York State in the late 1990s and early 2000s. The goal of the experiment was to precisely measure one property of the muon—the particles’ precession, or wobble, in a magnetic field. The final results were surprising, hinting at the presence of previously unknown phantom particles or forces affecting the muon’s properties.

The new experiment at Fermilab will make use of the laboratory’s intense beam of muons to definitively answer the questions the Brookhaven experiment raised. And since it would have cost 10 times more to build a completely new machine at Brookhaven rather than move the magnet to Fermilab, the Muon g-2 team transported that large, fragile superconducting magnet in one piece from Long Island to the suburbs of Chicago in the summer of 2013.

The magnet took a barge south around Florida, up the Tennessee-Tombigbee waterway and the Illinois River, and was then driven on a specially designed truck over three nights to Fermilab. And thanks to a GPS-powered map online, it collected thousands of fans over its journey, making it one of the most well-known electromagnets in the world.
“Getting the magnet here was only half the battle,” says Chris Polly, project manager of the Muon g-2 experiment. “Since it arrived, the team here at Fermilab has been working around the clock installing detectors, building a control room and, for the past year, adjusting the uniformity of the magnetic field, which must be precisely known to an unprecedented level to obtain any new physics. It’s been a lot of work, but we’re ready now to really get started.”

That work has included the creation of a new beamline to deliver a pure beam of muons to the ring, the installation of a host of instrumentation to measure both the magnetic field and the muons as they circulate within it, and a year-long process of “shimming” the magnet, inserting tiny pieces of metal by hand to shape the magnetic field. The field created by the magnet is now three times more uniform than the one it created at Brookhaven.

Over the next few weeks the Muon g-2 team will test the equipment installed around the magnet, which will be storing and measuring muons for the first time in 16 years. Later this year, they will start taking science-quality data, and if their results confirm the anomaly first seen at Brookhaven, it will mean that the elegant picture of the universe that scientists have been working on for decades is incomplete, and that new particles or forces may be out there, waiting to be discovered.

“It’s an exciting time for the whole team, and for physics,” says David Hertzog of the University of Washington, co-spokesperson of the Muon g-2 collaboration. “The magnet has been working, and working fantastically well. It won’t be long until we have our first results, and a better view through the window that the Brookhaven experiment opened for us.”

First results from search for a dark light
-Symmetry Magazine
By Manuel Gnida

The Heavy Photon Search at Jefferson Lab is looking for a hypothetical particle from a hidden “dark sector.”

In 2015, a group of researchers installed a particle detector just half of a millimeter away from an extremely powerful electron beam. The detector could either start them on a new search for a hidden world of particles and forces called the “dark sector”—or its sensitive parts could burn up in the beam.

Earlier this month, scientists presented the results from that very first test run at the Heavy Photon Search collaboration meeting at the US Department of Energy’s Thomas Jefferson National Accelerator Facility. To the scientists’ delight, the experiment is working flawlessly.

Dark sector particles could be the long-sought components of dark matter, the mysterious form of matter thought to be five times more abundant in the universe than regular matter. To be specific, HPS is looking for a dark-sector version of the photon, the elementary “particle of light” that carries the fundamental electromagnetic force in the Standard Model of particle physics.

Analogously, the dark photon would be the carrier of a force between dark-sector particles. But unlike the regular photon, the dark photon would have mass. That’s why it’s also called the heavy photon.

To search for dark photons, the HPS experiment uses a very intense, nearly continuous beam of highly energetic electrons from Jefferson Lab’s CEBAF accelerator. When slammed into a tungsten target, the electrons radiate energy that could potentially produce the mystery particles. Dark photons are believed to quickly decay into pairs of electrons and their antiparticles, positrons, which leave tracks in the HPS detector.

“Dark photons would show up as an anomaly in our data—a very narrow bump on a smooth background from other processes that produce electron-positron pairs,” says Omar Moreno from SLAC National Accelerator Laboratory, who led the analysis of the first data and presented the results at the collaboration meeting.

The challenge is that, due to the large beam energy, the decay products are compressed very narrowly in beam direction. To catch them, the detector must be very close to the electron beam. But not too close—the smallest beam movements could make the beam swerve into the detector. Even if the beam doesn’t directly hit the HPS apparatus, electrons interacting in the target can scatter into the detector and cause unwanted signals.

The HPS team implemented a number of precautions to make sure their detector could handle the potentially destructive beam conditions. They installed and carefully aligned a system to intercept any large beam motions, made the detector’s support structure movable to bring the detector close to the beam and measure the exact beam position, and installed a feedback system that would shut the beam down if its motions were too large. They also placed their whole setup in vacuum because interactions of the beam with gas molecules would create too much background. Finally, they cooled the detector to negative 30 degrees Fahrenheit to reduce the effects of radiation damage. These measures allowed the team to operate their experiment so close to the beam.

“That’s maybe as close as anyone has ever come to such a particle beam,” says John Jaros, head of the HPS group at SLAC, which built the innermost part of the HPS detector, the Silicon Vertex Tracker. “So, it was fairly exciting when we gradually decreased the distance between the detector and the beam for the first time and saw that everything worked as planned. A large part of that success lies with the beautiful beams Jefferson Lab provided.”

SLAC’s Mathew Graham, who oversees the HPS analysis group, says, “In addition to figuring out if we can actually do the experiment, the first run also helped us understand the background signals in the experiment and develop the data analysis tools we need for our search for dark photons.”

So far, the team has seen no signs of dark photons. But to be fair, the data they analyzed came from just 1.7 days of accumulated running time. HPS collects data in short spurts when the CLAS experiment, which studies protons and neutrons using the same beam line, is not in use.
A second part of the analysis is still ongoing: The researchers are also closely inspecting the exact location, or vertex, from which an electron-positron pair emerges.

“If a dark photon lives long enough, it might make it out of the tungsten target where it was produced and travel some distance through the detector before it decays into an electron-positron pair,” Moreno says. The detector was specifically designed to observe such a signal.
Jefferson Lab has approved the HPS project for a total of 180 days of experimental time. Slowly but surely, HPS scientists are finding chances to use it

NASA's Fermi mission expands its search for dark matter

Dark matter, the mysterious substance that constitutes most of the material universe, remains as elusive as ever. Although experiments on the ground and in space have yet to find a trace of dark matter, the results are helping scientists rule out some of the many theoretical possibilities. Three studies published earlier this year, using six or more years of data from NASA’s Fermi Gamma-ray Space Telescope, have broadened the mission’s dark matter hunt using some novel approaches.

“We’ve looked for the usual suspects in the usual places and found no solid signals, so we’ve started searching in some creative new ways,” said Julie McEnery, Fermi project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “With these results, Fermi has excluded more candidates, has shown that dark matter can contribute to only a small part of the gamma-ray background beyond our galaxy, the Milky Way, and has produced strong limits for dark matter particles in the second-largest galaxy orbiting it.”

Dark matter neither emits nor absorbs light, primarily interacts with the rest of the universe through gravity, yet accounts for about 80 percent of the matter in the universe. Astronomers see its effects throughout the cosmos – in the rotation of galaxies, in the distortion of light passing through galaxy clusters, and in simulations of the early universe, which require the presence of dark matter to form galaxies at all.

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Researchers map quantum vortices inside superfluid helium nanodroplets

First ever snapshots of spinning nanodroplets reveal surprising features

Scientists have, for the first time, characterized so-called quantum vortices that swirl within tiny droplets of liquid helium. The research, led by scientists at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab), the University of Southern California, and SLAC National Accelerator Laboratory, confirms that helium nanodroplets are in fact the smallest possible superfluidic objects and opens new avenues to study quantum rotation.

“The observation of quantum vortices is one of the most clear and unique demonstrations of the quantum properties of these microscopic objects,” says Oliver Gessner, senior scientist in the Chemical Sciences Division at Berkeley Lab. Gessner and colleagues, Andrey Vilesov of the University of Southern California and Christoph Bostedt of SLAC National Accelerator Laboratory at Stanford, led the multi-facility and multi-university team that published the work this week in Science.

The finding could have implications for other liquid or gas systems that contain vortices, says USC’s Vilesov. “The quest for quantum vortices in superfluid droplets has stretched for decades,” he says. “But this is the first time they have been seen in superfluid droplets.”

Superfluid helium has long captured scientist’s imagination since its discovery in the 1930s. Unlike normal fluids, superfluids have no viscosity, a feature that leads to strange and sometimes unexpected properties such as crawling up the walls of containers or dripping through barriers that contained the liquid before it transitioned to a superfluid.

Helium superfluidity can be achieved when helium is cooled to near absolute zero (zero kelvin or about -460 degrees F). At this temperature, the atoms within the liquid no longer vibrate with heat energy and instead settle into a calm state in which all atoms act together in unison, as if they were a single particle.

For decades, researchers have known that when superfluid helium is rotated–in a little spinning bucket, say–the rotation produces quantum vortices, swirls that are regularly spaced throughout the liquid. But the question remained whether anyone could see this behavior in an isolated, nanoscale droplet. If the swirls were there, it would confirm that helium nanodroplets, which can range in size from tens of nanometers to microns, are indeed superfluid throughout and that the motion of the entire liquid drop is that of a single quantum object rather than a mixture of independent particles.

But measuring liquid flow in helium nanodroplets has proven to be a serious challenge. “The way these droplets are made is by passing helium through a tiny nozzle that is cryogenically cooled down to below 10 Kelvin,” says Gessner. “Then, the nanoscale droplets shoot through a vacuum chamber at almost 200 meters-per-second. They live once for a few milliseconds while traversing the experimental chamber and then they’re gone. How do you show that these objects, which are all different from one another, have quantum vortices inside?”

The researchers turned to a facility at SLAC called the Linac Coherent Light Source (LCLS), a DOE Office of Science user facility that is the world’s first x-ray free-electron laser. This laser produces very short light pulses, lasting just a ten-trillionth of a second, which contain a huge number of high-energy photons. These intense x-ray pulses can effectively take snapshots of single, ultra-fast, ultra-small objects and phenomena.

“With the new x-ray free electron laser, we can now image phenomenon and look at processes far beyond what we could imagine just a decade ago,” says Bostedt of SLAC. “Looking at the droplets gave us a beautiful glimpse into the quantum world. It really opens the door to fascinating sciences.”

In the experiment, the researchers blasted a stream of helium nanodroplets across the x-ray laser beam inside a vacuum chamber; a detector caught the pattern that formed when the x-ray light diffracted off the drops.

The diffraction patterns immediately revealed that the shape of many droplets were not spheres, as was previously assumed. Instead, they were oblate. Just as the Earth’s rotation causes it to bulge at the equator, so too do rotating nanodroplets expand around the middle and flatten at the top and bottom.

But the vortices themselves are invisible to x-ray diffraction, so the researchers used a trick of adding xenon atoms to the droplets. The xenon atoms get pulled into the vortices and cluster together.

“It’s similar to pulling the plug in a bathtub and watching the kids’ toys gather in the vortex,” says Gessner. The xenon atoms diffract x-ray light much stronger than the surrounding helium, making the regular arrays of vortices inside the droplet visible. In this way, the researchers confirmed that vortices in nanodroplets behave as those found in larger amounts of rotating superfluid helium.

Armed with this new information, the researchers were able to determine the rotational speed of the nanodroplets. They were surprised to find that the nanodroplets spin up to 100,000 times faster than any other superfluid helium sample ever studied in a laboratory.

Moreover, while normal liquid drops will change shape as they spin faster and faster–to resemble a peanut or multi-lobed globule, for instance–the researchers saw no evidence of such shapeshifting in the helium nanodroplets. “Essentially, we’re exploring a new regime of quantum rotation with this matter,” Gessner says.

“It’s a new kind of matter in a sense because it is a self-contained isolated superfluid,” he adds. “It’s just all by itself, held together by its own surface tension. It’s pretty perfect to study these system

IMAGE…This is an illustration of analysis of superfluid helium nanodroplets. Droplets are emitted via a cooled nozzle (upper right) and probed with x-ray from the free-electron laser. The multicolored pattern (upper left) represents a diffraction pattern that reveals the shape of a droplet and the presence of quantum vortices such as those represented in the turquoise circle with swirls (bottom center).

Credit: Felix P. Sturm and Daniel S. Slaughter, Berkeley Lab.

Melissa Franklin

(born 1956) Experimental particle physicist

Melissa Eve Bronwen Franklin is the Mallinckrodt Professor of Physics at Harvard University. While working at the Fermi National Accelerator Laboratory in Chicago, her team is credited for the first evidence of the top quark. She is a fellow of the American Physical Society and former chair of the Harvard Physics department. 

Number 143 in an ongoing series celebrating remarkable women in science, technology, engineering, and mathematics.

Hello everyone on the earth and space.

I am Ricardo Marcenas, prime minister of Earth Federation Government.

The christian era will end soon, we make a step toward undiscovered world named the Universal Century.

この記念すべき瞬間に、地球連邦政府初代首相として′′みなさん′′に語りかけることができる幸福に、 まずは感謝を捧げたいと思います。
I express my gratitude for being able to adress to all of you at this memorable moment as the first prime minister of Earth Federation.

In my childhood president or prime minister used to address his nation.

Nation was structure for governing her citizen and territory, ultimately only for her defence.

いま、人類の宿願であった統一政権を現実のものとした我々は、旧来の定義における国家の過ちを指摘する ことができます。
Now we realize united government which was aspired by us all, we can point out faults of old nations.

We know a nation cannot function alone as much as we cannot live alone.

地球の危機という課題に対して、旧来の国家はなんら有効な解決策を示せませんでした。 二十世紀末葉から指摘され始めた人口問題、資源の枯渇、環境破壊による熱汚染……。
Old nations could not work out the solution of crisis like population issue,deplation of resource, heat pollution by enviromental destruction that was pointed out at middle 20th century.

いまや後戻りの許されないこれらの問題を解決するには、我々ひとりひとりの意識改革が不可欠だったので す。
It was crucial to reform our conciousness to solve these irreversible problems.

“A sence of self which belong to neither a nation nor an ethnic group, but to species, the human race”

If we had not acquired this perspective, we could not sustain ourselves until today.

前身機関の設立から五十年あまり、人類宇宙移民計画とともに歩んできた地球連邦政府の歴史は、決して平 坦なものではありませんでした。
Since the predesessor has instituted fifty years ago, the history of Earth Federation Government progressed with space immigration program was never serene and fine.

国家、民族、宗教……これらの壁を取り払い、人類が本当にひとつになるためには、まだまだ多くの試練を 乗り越えなければならないことも事実です。
It is the fact that we have enoumous numbers of barrier to overcome like nation, race, and religion to truly unite into one.

However we have space colony as new place to live.

間もなく始まる宇宙世紀とともに移民も本格化し、多くの人が宇宙で暮らすことを当たり前とする時代が来 るでしょう。
Space immigration will be fully in progress soon, and living in space will be come commonplace.

Our cooperation achieved this brilliant success made for save the earth which is about to be crushed by weight of human.

西暦と呼ばれた時期が、人類が人類たるアイデンティティを確立した揺籃期とするなら、宇宙世紀はその次 を目指す時間となることでしょう。
If in the Christian era we were in early development stage to forge an identity as mankind, in the Universal Century we would head to next stage.

We have decided not to reduce population by birth control, but develop the outside space compatible with our population.

A baby crawled out of the cradle must grow up.

The implementation of space immigration program has proved that we can unite for common purpose.

では、その次は? Then, what comes next?

宇宙世紀 ユニバーサル・センチュリー。 The Universal Century.
The word “Universal” was employed for multiple meanings appropriately reflecting its philosophy.

We should have named Universe Century, because new century will be a space age century.

我々は敢えて用法違いと思われる “ 普遍的 ”(ユニバーサル)を選び、新しい世紀の名前としました
How ever, we had choosed Universal Century as a new cetury’s name, this may be wrong.

I was born in former United States, have passed my childhood in Germany and French,

and my schooltime in Asia. My wife is hybrid of Europian and Arabic.

わたしの両親も似たようなもので、祖先を振り返ると、実に三十以上の国の血が混じり合い、いまのわたし が形作られていることがわかります。
My parents are similar, for ancesters were from over thirty country in total.

It means that varying colors of skin, varying bloods of race are living in me.

I recieved honor of being Eearth Federation President, since the “universal” birth.

There must be many people have such a birth in you.

二十一世紀から本格的に始まった通信技術の発達、相互依存経済による世界の並列化が、血と肌の混合を推 し進めたのです。
Amalgamation of skin and blood was caused by globalization of economical activity and development of communication technology that rapidly progressed in 21st century,

連邦政府の樹立による国境の無力化と、世界標準語の制定によって、この傾向は今後ますます加速すること と思います。
and this tendency will be accelerated by disempowerment of national borders by Earth Federation and instituition of world standard language.

Therefore my case is no longer uncommon.

宇宙で人が暮らすということ。 そのために、全人類が一丸となって移民計画を推進してきたことも、また然りです。
The fact we have worked together toward space immigration for giving space habitude is also similar.

This miraculous achievement must not be treated as special case.

人類はひとつになれるという事実を普遍化し、互いを拒絶することなく、憎しみ争うことなく、一個の種と して広大な宇宙と向き合ってゆく。
We should universalize the fact that we mankind can cooperate hand in hand.

We should face to boundless univerce as a species without boycotte, hate or conflict each other.

I am not a believer of any religion but not an atheist too.

高みを目指すため、自らの戒めとするため、己の中により高次な存在を設定するのは、人の健康な精神活動 の表れと信じています。

We fix higher existance inside our mind to ascend to higher stage or to admonish ourselves, I believe it is sound mental activity of humanity.

In christian era, philosophical problems, for instance how should live or how should we face to the world, were mentioned through prophecy or words of god.

人はどのように生きるべきか。いかにして世界と向き合うべきか。 モーセが授かった十戒の例を持ち出すまでもなく、それらに対する教えはあらゆる宗教に伝えられています。

All religions have doctorine on such problems, not in words of human, but in narrative of contract between god and human.


However since we say farewell to the “century of god” soon, it is time to contract renewal.

Now it is time to discuss these problems not with transcendent god as ever,

今度は超越者としての神ではなく、我々の内に存在する神――より高みに近づこうとする心との対話によっ て。
but with our inner god, in other words our mind ahead to higher stage.

The new Ark of the Covenant of Universal Century should be established by consensous of all human race.

この首相官邸の名前、〈ラプラス〉の語源をについてはご存じの方も多いでしょう。 十八世紀のフランスに生まれた物理学者の名前です。
As many of you know, this office of prime minister is named after the French physicist in the 18th century.

ラプラスは、過去に起こったすべての事象を細大もらさず――原子一個の動きに至るまで――分析すること で、未来は完全に予測できると考えました。
He supposed that we can completely predict the future by obtaining and analyzing all information of event occurent in past even a motion of an atom.

この考えは、のちに量子力学の発達によって否定され、いまでは未来を完全に予測する術はないことが証明 されています。
His thought is negated by quantum mechanics and it is proved that we have no way to predict the future completely.

我々は、その経緯を逆説として受け取り、この首相官邸〈ラプラス〉の名を冠しました。 「未来にはあらゆる可能性がある」という意味を込めてのことです。
We paradoxically use his name for the thesis “The future has infinite potential”.

ご承知の通り、地球軌道上のステーションに首相官邸を置くことについては、さまざまな議論がありました。 交通の利便性や警備上の観点からすると、確かに望ましい選択とは言えません。
As you are aware construction of the office of prime minister on the orbital station was controvertial because it is nonideal in terms of security and accessibility.

しかし、我々は宇宙世紀に踏み出そうとしているのです。 この宇宙こそが人類の新たな生活の場となるのです。 その途上に立つ者として、地球と宇宙の狭間に身を置かねばわからぬこともあると思い、わたしは首相権限 でこれを押し通しました。
But at this juncture, I should take my stand between earth and space in which people will live in as one in the transition period, so I have pushed through the transfarring of the office by authority of prime minister.

西暦の最後の日、改暦セレモニーとともに宇宙世紀憲章を発表するのであれば、その舞台はここを置いて他 にないとも考えました。
Also I believe that no other place is suitable for holding the calender reform ceremony and release the Charter of Universal Century at the last day of the Christian era.

今日、ここには地球連邦政府を構成する百ヵ国あまりの代表が集い、吟味に吟味を重ねた宇宙世紀憲章にサ インをしました。
Today delegations from over hundred nations which consist the Earth Federation Government put their signature to the Charter of Universal Century which was strictly scrutinized by them.

間もなく発表されるそれは、のちにラプラス憲章と呼ばれ、人と世界の新たな契約の箱として機能すること になるでしょう。
It is going to be released soon and will be called The Laplace Charter later, will become effective as the new Ark of Covenant.

In the Charter under consensuos of Earth Federation Government, there is neither name of god nor reference to “original sin”.

When you are ahead, the Last Judgment and visit if from now, it will be a catastrophe the heart of our own I sent invitation.

Everything is up to us.

Now, we are facing to vast universe.

We are facing to unremittingly vacillate future which has infinite potential.

We should not bring antagonism of past days no matter what kind of process led us to here.

我々はスタート地点にいるのです。 We are standing on starting point.

Look ahead of the future by the eye of your inner god, not by scinario written by others.

現在、グリニッジ標準時二十三時五十九分。 Now it is 23:59 in Greenwich standard time.

Soon it will be new century.

I sincerely ask you to pray for our future and think of passed century in which we were all part of, if you afford to do.

May human race advance to space be untroubled.

May Universal Century be rewarding era.

Believe in god inside your mind

我々の中に眠る、可能性という名の神を信じて… Believe in potential inside human race…

—  地球連邦政府首相 リカルド・マーセナス首相演説 - ガンダムUC

Here at Brookhaven, we rang in the new year with a big milestone. Engineers at our new National Synchrotron Light Source II (the enormous silver ring building in the photo) began commissioning the accelerators and boosters  that will push electrons to very nearly the speed of light to produce x-rays and UV rays that scientists will use to explore all kinds of materials, from biological samples to battery cores. 

Late on December 31, our technicians turned on the light source. They fired the electron gun (a hot cathode in a vacuum that produces electrons), sped the electrons up in the linear accelerator, and then shot them around the half-mile ring in the wee hours of January 1. The electrons reached three billion electron volts, the maximum design energy of the new facility. 

In the coming year, we’ll be testing all the parts of the accelerators, and then we’ll be opening up the beamlines for some hard-core science! 

Scientists complete the top quark puzzle

Scientists on the CDF and DZero experiments at the U.S. Department of Energy’s Fermi National Accelerator Laboratory have announced that they have found the final predicted way of creating a top quark, completing a picture of this particle nearly 20 years in the making.

The two collaborations jointly announced on Friday, Feb. 21 that they had observed one of the rarest methods of producing the elementary particle – creating a single top quark through the weak nuclear force, in what is called the “s-channel.” For this analysis, scientists from the CDF and DZero collaborations sifted through data from more than 500 trillion proton-antiproton collisions produced by the Tevatron from 2001 to 2011. They identified about 40 particle collisions in which the weak nuclear force produced single top quarks in conjunction with single bottom quarks.

Top quarks are the heaviest and among the most puzzling elementary particles. They weigh even more than the Higgs boson – as much as an atom of gold – and only two machines have ever produced them: Fermilab’s Tevatron and the Large Hadron Collider at CERN. There are several ways to produce them, as predicted by the theoretical framework known as the Standard Model, and the most common one was the first one discovered: a collision in which the strong nuclear force creates a pair consisting of a top quark and its antimatter cousin, the anti-top quark.

Collisions that produce a single top quark through the weak nuclear force are rarer, and the process scientists on the Tevatron experiments have just announced is the most challenging of these to detect. This method of producing single top quarks is among the rarest interactions allowed by the laws of physics. The detection of this process was one of the ultimate goals of the Tevatron, which for 25 years was the most powerful particle collider in the world.

“This is an important discovery that provides a valuable addition to the picture of the Standard Model universe,” said James Siegrist, DOE Associate Director of Science for High Energy Physics. “It completes a portrait of one of the fundamental particles of our universe, by showing us one of the rarest ways to create them.”

Searching for single top quarks is like looking for a needle in billions of haystacks. Only one in every 50 billion Tevatron collisions produced a single s-channel top quark, and the CDF and DZero collaborations only selected a small fraction of those to separate them from background, which is why the number of observed occurrences of this particular channel is so small. However, the statistical significance of the CDF and DZero data exceeds that required to claim a discovery.

“Kudos to the CDF and DZero collaborations for their work in discovering this process,” said Saul Gonzalez, program director for the National Science Foundation. “Researchers from around the world, including dozens of universities in the United States, contributed to this important find.”

The CDF and DZero experiments first observed particle collisions that created single top quarks through a different process of the weak nuclear force in 2009. This observation was later confirmed by scientists using the Large Hadron Collider.

Scientists from 27 countries collaborated on the Tevatron CDF and DZero experiments and continue to study the reams of data produced during the collider’s run, using ever more sophisticated techniques and computing methods.

“I’m pleased that the CDF and DZero collaborations have brought their study of the top quark full circle,” said Fermilab Director Nigel Lockyer. “The legacy of the Tevatron is indelible, and this discovery only makes the breadth of that research even more remarkable.”

IMAGE….This diagram shows the process for creating single top quarks through the s-channel. A quark from an incoming proton interacts in the Tevatron with an antiquark from an incoming antiproton, forming a W boson with much greater mass. This W boson then decays into a top quark and an antibottom quark, which can be seen in the CDF and DZero detectors. Credit: Fermilab


My feet were in some cool spots last week: 

  1. A superconducting radio-frequency cavity test center
  2. The line that marks out a future high-energy x-ray beamline
  3. The crazy 70s-esque foyer of the Fermi National Accelerator Laboratory
  4. A mine 300 feet beneath the earth where neutrinos are created and measured

This is a 2011 photo posted by Fermilab of the Department of Energy’s COUPP dark matter experiment, which is designed to detect the mysterious stuff that is thought to make up a large part of the universe’s mass. Dark matter rarely interacts with our sensible world, neither emitting nor absorbing radiation.

That’s why scientists searching for it put this detector a mile and a half underground. At the experiment’s heart is a jar filled with water and an ingredient found in fire extinguishers. A Fermilab statement says the mixture is kept under pressure at just above the boiling point so that no bubbles form. When an energetic particle passes through the jar, it interacts with an atom of the liquid mixture and release enough energy to form a bubble.

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