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  • richardmitnick 2:39 pm on December 9, 2022 Permalink | Reply
    Tags: "Nuclear Physics Gets a Boost for High-Performance Computing", , , , , Jefferson Lab’s Center for Theoretical and Computational Physics., , , The DOE's Thomas Jefferson National Accelerator Facility   

    From The DOE’s Thomas Jefferson National Accelerator Facility : “Nuclear Physics Gets a Boost for High-Performance Computing” 

    From The DOE’s Thomas Jefferson National Accelerator Facility

    12.6.22
    Kandice Carter
    Jefferson Lab Communications Office
    kcarter@jlab.org

    1
    Jefferson Lab’s Data Center, JLab photo: Aileen Devlin

    2
    The Frontier Supercomputer, OLCF at The DOE’s Oak Ridge National Lab photo.

    Efforts to harness the power of supercomputers to better understand the hidden worlds inside the nucleus of the atom recently received a big boost. A project led by the DOE’s Thomas Jefferson National Accelerator Facility is one of three to split $35 million in grants from the DOE via a partnership program of DOE’s Scientific Discovery through Advanced Computing (SciDAC).

    Each of the projects receiving the grants are joint projects between DOE’s Nuclear Physics (NP) and Advanced Scientific Computing Research (ASCR) programs via a partnership program of SciDAC.

    Making the Most of Advanced Computational Resources

    As supercomputers become ever-more powerful, scientists need advanced tools to take full advantage of their capabilities. For example, the Oak Ridge Leadership Computing Facility (OLCF) at DOE’s Oak Ridge National Lab now hosts the world’s first public exascale supercomputer. Its Frontier supercomputer has achieved 1 exaFLOPS in capability by demonstrating it can perform one billion-billion calculations per second.

    “Nuclear physics is a rich, diverse and exciting area of research explaining the origins of visible matter. And in nuclear physics, high-performance computing is a critically important tool in our efforts to unravel the origins of nuclear matter in our universe,” said Robert Edwards, a senior staff scientist and deputy group leader of Jefferson Lab’s Center for Theoretical and Computational Physics.

    Edwards is the principal investigator for one of the three projects. His project, “Fundamental nuclear physics at the exascale and beyond,” will build a solid foundation of software resources for nuclear physicists to address key questions regarding the building blocks of the visible universe. The project seeks to help nuclear physicists tease out questions about the basic properties of particles, such as the ubiquitous proton.

    “One of the key research questions that we hope to one day answer is what is the origin of a particle’s mass, what is the origin of its spin, and what are the emerging properties of a dense system of particles?” explained Edwards.

    The $13 million project includes key scientists based at six DOE national labs and two universities, including Jefferson Lab, The DOE’s Argonne National Lab, The DOE’s Brookhaven National Lab, Oak Ridge National Lab, The DOE’sLawrence Berkeley National Lab, The DOE’s Los Alamos National Lab, The Massachusetts Institute of Technology and The College of William & Mary.

    It aims to optimize the software tools needed for calculations of quantum chromodynamics (“QCD”). QCD is the theory that describes the structure of protons and neutrons – the particles that make up atomic nuclei – as well as provide insight to other particles that help build our universe. Protons are built of smaller particles called quarks held together by a force-fed glue manifesting as gluon particles. What’s not clear is how the proton’s properties arise from quarks and gluons.

    “The evidence points to the mass of quarks as extremely tiny, only 1%. The rest is from the glue. So, what part does glue play in that internal structure?” he said.

    Modeling the Subatomic Universe

    The goal of the supercomputer calculations is to mimic how quarks and gluons experience the real world at their own teensy scale in a way that can be calculated by computers. To do that, the nuclear physicists use supercomputers to first generate a snapshot of the environment inside a proton where these particles live for the calculations. Then, they mathematically drop in some quarks and glue and use supercomputers to predict how they interact. Averaging over thousands of these snapshots gives physicists a way to emulate the particles’ lives in the real world.

    Solutions from these calculations will provide input for experiments taking place today at Jefferson Lab’s Continuous Electron Beam Accelerator Facility (CEBAF)[below] and Brookhaven Lab’s Relativistic Heavy Ion Collider (RHIC).

    CEBAF and RHIC are both DOE Office of Science user facilities.

    “While we did not base this proposal on the requirements of the future Electron-Ion Collider, many of the problems that we are trying to address now, such as code infrastructures and methodology, will impact the EIC,” Edwards added.

    The project will use a four-pronged approach to help streamline these calculations for better use on supercomputers, while also preparing for ever-more-powerful machines to come online.

    The first two approaches relate to generation of the quarks’ and gluons’ little slice of the universe. The researchers aim to make this task easier for computers by streamlining the process with upgraded software and by using software to break down this process into smaller chunks of calculations that will be easier for a computer to calculate. The second part of this project will then bring in machine learning to see if the existing algorithms can be improved by additional computer modelling.

    The third approach involves exploring and testing out new techniques for the portion of the calculations that model how quarks and gluons interact in their computer-generated universe.

    The fourth and last approach will collect all of the information from the first three prongs and begin to scale them for use on next-generation supercomputers.

    All three SciDAC projects awarded grants by DOE span efforts in nuclear physics research. Together, the projects address fundamental questions about the nature of nuclear matter, including the properties of nuclei, nuclear structure, nucleon imaging, and discovering exotic states of quarks and gluons.

    “The SciDAC partnership projects deploy high-performance computing and enable world-leading science discoveries in our nuclear physics facilities,” said Timothy Hallman, DOE’s associate director of science for NP.

    The total funding announced by DOE includes $35 million lasting five years, with $7.2 million in Fiscal Year 2022 and outyear funding contingent on congressional appropriations.

    See the full article here .

    Comments are invited and will be appreciated, especially if the reader finds any errors which I can correct. Use “Reply”.

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    JLab campus
    The DOE’s Thomas Jefferson National Accelerator Facility is supported by The Office of Science of the U.S. Department of Energy. DOE’s Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, visit science.energy.gov.

    Jefferson Science Associates, LLC, a joint venture of the Southeastern Universities Research Association, Inc. and PAE Applied Technologies, manages and operates the Thomas Jefferson National Accelerator Facility for the U.S. Department of Energy’s Office of Science.

    History

    The DOE’s Thomas Jefferson National Accelerator Facility was established in 1984 (first initial funding by the Department of Energy) as the Continuous Electron Beam Accelerator Facility (CEBAF); the name was changed to Thomas Jefferson National Accelerator Facility in 1996. The full funding for construction was appropriated by US Congress in 1986 and on February 13, 1987, the construction of the main component, the CEBAF accelerator begun. First beam was delivered to experimental area on 1 July 1994. The design energy of 4 GeV for the beam was achieved during the year 1995. The laboratory dedication took place 24 May 1996 (at this event the name was also changed). Full initial operations with all three initial experiment areas online at the design energy was achieved on June 19, 1998. On August 6, 2000 the CEBAF reached “enhanced design energy” of 6 GeV. In 2001, plans for an energy upgrade to 12 GeV electron beam and plans to construct a fourth experimental hall area started. The plans progressed through various DOE Critical Decision-stages in the 2000s decade, with the final DOE acceptance in 2008 and the construction on the 12 GeV upgrade beginning in 2009. May 18, 2012 the original 6 GeV CEBAF accelerator shut down for the replacement of the accelerator components for the 12 GeV upgrade. 178 experiments were completed with the original CEBAF.

    In addition to the accelerator, the laboratory has housed and continues to house a free electron laser (FEL) instrument. The construction of the FEL started 11 June 1996. It achieved first light on June 17, 1998. Since then, the FEL has been upgraded numerous times, increasing its power and capabilities substantially.

    Jefferson Lab was also involved in the construction of the Spallation Neutron Source (SNS) at DOE’s Oak Ridge National Laboratory . Jefferson built the SNS superconducting accelerator and helium refrigeration system. The accelerator components were designed and produced 2000–2005.

    Accelerator

    The laboratory’s main research facility is the CEBAF accelerator, which consists of a polarized electron source and injector and a pair of superconducting RF linear accelerators that are 7/8-mile (1400 m) in length and connected to each other by two arc sections that contain steering magnets.

    As the electron beam makes up to five successive orbits, its energy is increased up to a maximum of 6 GeV (the original CEBAF machine worked first in 1995 at the design energy of 4 GeV before reaching “enhanced design energy” of 6 GeV in 2000; since then, the facility has been upgraded into 12 GeV energy). This leads to a design that appears similar to a racetrack when compared to the classical ring-shaped accelerators found at sites such as The European Organization for Nuclear Research [La Organización Europea para la Investigación Nuclear][Organization européenne pour la recherche nucléaire] [Europäische Organization für Kernforschung](CH)[CERN] or DOE’s Fermi National Accelerator Laboratory. Effectively, CEBAF is a linear accelerator, similar to The DOE’s SLAC National Accelerator Laboratory at Stanford University, that has been folded up to a tenth of its normal length.

    The design of CEBAF allows the electron beam to be continuous rather than the pulsed beam typical of ring-shaped accelerators. (There is some beam structure, but the pulses are very much shorter and closer together.) The electron beam is directed onto three potential targets (see below). One of the distinguishing features of Jefferson Lab is the continuous nature of the electron beam, with a bunch length of less than 1 picosecond. Another is Jefferson Lab’s use of superconducting Radio Frequency (SRF) technology, which uses liquid helium to cool niobium to approximately 4 K (−452.5 °F), removing electrical resistance and allowing the most efficient transfer of energy to an electron. To achieve this, Jefferson Lab houses the world’s largest liquid helium refrigerator, and it was one of the first large-scale implementations of SRF technology. The accelerator is built 8 meters below the Earth’s surface, or approximately 25 feet, and the walls of the accelerator tunnels are 2 feet thick.

    The beam ends in four experimental halls, labelled Hall A, Hall B, Hall C, and Hall D. Each hall contains specialized spectrometers to record the products of collisions between the electron beam or with real photons and a stationary target. This allows physicists to study the structure of the atomic nucleus, specifically the interaction of the quarks that make up protons and neutrons of the nucleus.

    With each revolution around the accelerator, the beam passes through each of the two LINAC accelerators, but through a different set of bending magnets in semi-circular arcs at the ends of the linacs. The electrons make up to five passes through the linear accelerators.

    When a nucleus in the target is hit by an electron from the beam, an “interaction”, or “event”, occurs, scattering particles into the hall. Each hall contains an array of particle detectors that track the physical properties of the particles produced by the event. The detectors generate electrical pulses that are converted into digital values by analog-to-digital converters (ADCs), time to digital converters (TDCs) and pulse counters (scalers).

    This digital data is gathered and stored so that the physicist can later analyze the data and reconstruct the physics that occurred. The system of electronics and computers that perform this task is called a data acquisition system.

    12 GeV upgrade

    As of June 2010, construction began on a $338 million upgrade to add an end station, Hall D, on the opposite end of the accelerator from the other three halls, as well as to double beam energy to 12 GeV. Concurrently, an addition to the Test Lab, (where the SRF cavities used in CEBAF and other accelerators used worldwide are manufactured) was constructed.

    As of May 2014, the upgrade achieved a new record for beam energy, at 10.5 GeV, delivering beam to Hall D.

    As of December 2016, the CEBAF accelerator delivered full-energy electrons as part of commissioning activities for the ongoing 12 GeV Upgrade project. Operators of the Continuous Electron Beam Accelerator Facility delivered the first batch of 12 GeV electrons (12.065 Giga electron Volts) to its newest experimental hall complex, Hall D.

    In September 2017, the official notification from the DOE of the formal approval of the 12 GeV upgrade project completion and start of operations was issued. By spring 2018, all fours research areas were successfully receiving beam and performing experiments. On 2 May 2018 the CEBAF 12 GeV Upgrade Dedication Ceremony took place.

    As of December 2018, the CEBAF accelerator delivered electron beams to all four experimental halls simultaneously for physics-quality production running.

     
  • richardmitnick 7:40 am on October 20, 2022 Permalink | Reply
    Tags: "Physicists Confirm Hitch in Proton Structure", "Virtual Compton scattering", A new precision measurement has revealed a bump in the data in probes of the proton’s structure., A proton may appear as an opaque single particle or as a composite particle made of three quarks held together by the strong force., , , Electric polarizability is a fundamental property of proton structure., In "virtual Compton scattering" electrons interact with other particles by emitting an energetic photon or particle of light., Nuclear physicists have confirmed that the current description of proton structure isn’t all smooth sailing., , , , The DOE's Thomas Jefferson National Accelerator Facility, The new measurements of the proton’s electric polarizability reveal how susceptible the proton is to deformation-or stretching-in an electric field., Theory predicts that the more energetic electrons are more directly probing the strong force as it binds the quarks together to make the proton.   

    From The DOE’s Thomas Jefferson National Accelerator Facility : “Physicists Confirm Hitch in Proton Structure” 

    From The DOE’s Thomas Jefferson National Accelerator Facility

    10.19.22
    Kandice Carter
    Jefferson Lab Communications Office
    kcarter@jlab.org

    1
    The real photon that is produced in the virtual Compton scattering reaction provides the electromagnetic perturbation to the proton and allows to measure its electromagnetic generalized polarizabilities. Image courtesy of Nikos Sparveris, Temple University.

    Nuclear physicists have confirmed that the current description of proton structure isn’t all smooth sailing. A new precision measurement of the proton’s electric polarizability performed at the U.S. Department of Energy’s Thomas Jefferson National Accelerator Facility has revealed a bump in the data in probes of the proton’s structure. Though widely thought to be a fluke when seen in earlier measurements, this new, more precise measurement has confirmed the presence of the anomaly and raises questions about its origin. The research has just been published in the journal Nature [below].

    According to Ruonan Li, first author on the new paper and a graduate student at Temple University, measurements of the proton’s electric polarizability reveal how susceptible the proton is to deformation, or stretching, in an electric field. Like size or charge, the electric polarizability is a fundamental property of proton structure.

    What’s more, a precision determination of the proton’s electric polarizability can help bridge the different descriptions of the proton. Depending on how it is probed, a proton may appear as an opaque single particle or as a composite particle made of three quarks held together by the strong force.

    “We want to understand the substructure of the proton. And we can imagine it like a model with the three balanced quarks in the middle,” Li explained. “Now, put the proton in the electric field. The quarks have positive or negative charges. They will move in opposite directions. So, the electric polarizability reflects how easily the proton will be distorted by the electric field.”

    To probe this distortion, nuclear physicists used a process called “virtual Compton scattering”. It starts with a carefully controlled beam of energetic electrons from Jefferson Lab’s Continuous Electron Beam Accelerator Facility [below], a DOE Office of Science user facility. The electrons are sent crashing into protons.

    In “virtual Compton scattering”, electrons interact with other particles by emitting an energetic photon, or particle of light. The energy of the electron determines the energy of the photon it emits, which also determines how the photon interacts with other particles.

    Lower energy photons may bounce off the surface of the proton, while more energetic photons will blast inside the proton to interact with one of its quarks. Theory predicts that when these photon-quark interactions are plotted at from lower to higher energies, they will form a smooth curve.

    Nikos Sparveris, an associate professor of physics at Temple University and spokesperson for the experiment, said this simple picture didn’t hold up to scrutiny. The measurements instead revealed an as-yet-unexplained bump.

    “What we see is that there is some local enhancement to the magnitude of the polarizability. The polarizability decreases as the energy increases as expected. And, at some point, it appears to be coming temporarily up again before it will go down,” he said. “Based on our current theoretical understanding, it should follow a very simple behavior. We see something that deviates from this simple behavior. And this is the fact that is puzzling us at the moment.”

    The theory predicts that the more energetic electrons are more directly probing the strong force as it binds the quarks together to make the proton. This weird spike in the stiffness that nuclear physicists have now confirmed in the proton’s quarks signals that an unknown facet of the strong force may be at work.

    “There is something that we’re clearly missing at this point. The proton is the only composite building block in nature that is stable. So, if we are missing something fundamental there, it has implications or consequences for all of physics,” Sparveris confirmed.

    The physicists said that the next step is to further tease out the details of this anomaly and conduct precision probes to check for other points of deviation and to provide more information about the anomaly’s source.

    “We want to measure more points at various energies to present a clearer picture and to see if there is any further structure there,” Li said.

    Sparveris agreed.

    “We also need to measure precisely the shape of this enhancement. The shape is important to further elucidating the theory,” he said.

    Science paper:
    Nature

    Further reading:
    Experiment Proposal: E12-15-001 – Measurement of the Generalized Polarizabilities of the Proton in Virtual Compton Scattering 2016 .

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    JLab campus
    The DOE’s Thomas Jefferson National Accelerator Facility is supported by The Office of Science of the U.S. Department of Energy. DOE’s Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, visit science.energy.gov.

    Jefferson Science Associates, LLC, a joint venture of the Southeastern Universities Research Association, Inc. and PAE Applied Technologies, manages and operates the Thomas Jefferson National Accelerator Facility for the U.S. Department of Energy’s Office of Science.

    History

    The DOE’s Thomas Jefferson National Accelerator Facility was established in 1984 (first initial funding by the Department of Energy) as the Continuous Electron Beam Accelerator Facility (CEBAF); the name was changed to Thomas Jefferson National Accelerator Facility in 1996. The full funding for construction was appropriated by US Congress in 1986 and on February 13, 1987, the construction of the main component, the CEBAF accelerator begun. First beam was delivered to experimental area on 1 July 1994. The design energy of 4 GeV for the beam was achieved during the year 1995. The laboratory dedication took place 24 May 1996 (at this event the name was also changed). Full initial operations with all three initial experiment areas online at the design energy was achieved on June 19, 1998. On August 6, 2000 the CEBAF reached “enhanced design energy” of 6 GeV. In 2001, plans for an energy upgrade to 12 GeV electron beam and plans to construct a fourth experimental hall area started. The plans progressed through various DOE Critical Decision-stages in the 2000s decade, with the final DOE acceptance in 2008 and the construction on the 12 GeV upgrade beginning in 2009. May 18, 2012 the original 6 GeV CEBAF accelerator shut down for the replacement of the accelerator components for the 12 GeV upgrade. 178 experiments were completed with the original CEBAF.

    In addition to the accelerator, the laboratory has housed and continues to house a free electron laser (FEL) instrument. The construction of the FEL started 11 June 1996. It achieved first light on June 17, 1998. Since then, the FEL has been upgraded numerous times, increasing its power and capabilities substantially.

    Jefferson Lab was also involved in the construction of the Spallation Neutron Source (SNS) at DOE’s Oak Ridge National Laboratory . Jefferson built the SNS superconducting accelerator and helium refrigeration system. The accelerator components were designed and produced 2000–2005.

    Accelerator

    The laboratory’s main research facility is the CEBAF accelerator, which consists of a polarized electron source and injector and a pair of superconducting RF linear accelerators that are 7/8-mile (1400 m) in length and connected to each other by two arc sections that contain steering magnets.

    As the electron beam makes up to five successive orbits, its energy is increased up to a maximum of 6 GeV (the original CEBAF machine worked first in 1995 at the design energy of 4 GeV before reaching “enhanced design energy” of 6 GeV in 2000; since then, the facility has been upgraded into 12 GeV energy). This leads to a design that appears similar to a racetrack when compared to the classical ring-shaped accelerators found at sites such as The European Organization for Nuclear Research [La Organización Europea para la Investigación Nuclear][Organization européenne pour la recherche nucléaire] [Europäische Organization für Kernforschung](CH)[CERN] or DOE’s Fermi National Accelerator Laboratory. Effectively, CEBAF is a linear accelerator, similar to The DOE’s SLAC National Accelerator Laboratory at Stanford University, that has been folded up to a tenth of its normal length.

    The design of CEBAF allows the electron beam to be continuous rather than the pulsed beam typical of ring-shaped accelerators. (There is some beam structure, but the pulses are very much shorter and closer together.) The electron beam is directed onto three potential targets (see below). One of the distinguishing features of Jefferson Lab is the continuous nature of the electron beam, with a bunch length of less than 1 picosecond. Another is Jefferson Lab’s use of superconducting Radio Frequency (SRF) technology, which uses liquid helium to cool niobium to approximately 4 K (−452.5 °F), removing electrical resistance and allowing the most efficient transfer of energy to an electron. To achieve this, Jefferson Lab houses the world’s largest liquid helium refrigerator, and it was one of the first large-scale implementations of SRF technology. The accelerator is built 8 meters below the Earth’s surface, or approximately 25 feet, and the walls of the accelerator tunnels are 2 feet thick.

    The beam ends in four experimental halls, labelled Hall A, Hall B, Hall C, and Hall D. Each hall contains specialized spectrometers to record the products of collisions between the electron beam or with real photons and a stationary target. This allows physicists to study the structure of the atomic nucleus, specifically the interaction of the quarks that make up protons and neutrons of the nucleus.

    With each revolution around the accelerator, the beam passes through each of the two LINAC accelerators, but through a different set of bending magnets in semi-circular arcs at the ends of the linacs. The electrons make up to five passes through the linear accelerators.

    When a nucleus in the target is hit by an electron from the beam, an “interaction”, or “event”, occurs, scattering particles into the hall. Each hall contains an array of particle detectors that track the physical properties of the particles produced by the event. The detectors generate electrical pulses that are converted into digital values by analog-to-digital converters (ADCs), time to digital converters (TDCs) and pulse counters (scalers).

    This digital data is gathered and stored so that the physicist can later analyze the data and reconstruct the physics that occurred. The system of electronics and computers that perform this task is called a data acquisition system.

    12 GeV upgrade

    As of June 2010, construction began on a $338 million upgrade to add an end station, Hall D, on the opposite end of the accelerator from the other three halls, as well as to double beam energy to 12 GeV. Concurrently, an addition to the Test Lab, (where the SRF cavities used in CEBAF and other accelerators used worldwide are manufactured) was constructed.

    As of May 2014, the upgrade achieved a new record for beam energy, at 10.5 GeV, delivering beam to Hall D.

    As of December 2016, the CEBAF accelerator delivered full-energy electrons as part of commissioning activities for the ongoing 12 GeV Upgrade project. Operators of the Continuous Electron Beam Accelerator Facility delivered the first batch of 12 GeV electrons (12.065 Giga electron Volts) to its newest experimental hall complex, Hall D.

    In September 2017, the official notification from the DOE of the formal approval of the 12 GeV upgrade project completion and start of operations was issued. By spring 2018, all fours research areas were successfully receiving beam and performing experiments. On 2 May 2018 the CEBAF 12 GeV Upgrade Dedication Ceremony took place.

    As of December 2018, the CEBAF accelerator delivered electron beams to all four experimental halls simultaneously for physics-quality production running.

     
  • richardmitnick 12:02 pm on September 2, 2022 Permalink | Reply
    Tags: "Particles Pick Pair Partners Differently in Small Nuclei", , Correlations may form between a proton and a neutron or between two protons or between two neutrons., , , Particles may pick different partners depending on how packed the nucleus is., The DOE's Thomas Jefferson National Accelerator Facility   

    From The DOE’s Thomas Jefferson National Accelerator Facility : “Particles Pick Pair Partners Differently in Small Nuclei” 

    From The DOE’s Thomas Jefferson National Accelerator Facility

    8.31.22
    Kandice Carter
    Jefferson Lab Communications Office
    kcarter@jlab.org

    1
    Tritium’s three nucleons can make up to three different short-range correlated pairs:

    Neutron 1 + Proton = pair one.
    Proton + Neutron 2 = pair two.
    Neutron 1 + Neutron 2 = pair three

    The protons and neutrons that build the nucleus of the atom frequently pair up. Now, a new high-precision experiment conducted at the U.S. Department of Energy’s Thomas Jefferson National Accelerator Facility has found that these particles may pick different partners depending on how packed the nucleus is.

    The data also reveal new details about short-distance interactions between protons and neutrons in nuclei and may impact results from experiments seeking to tease out further details of nuclear structure. The data are an order of magnitude more precise than previous studies, and the research has just been published in the journal Nature [below].

    Shujie Li is the lead author on the paper and a nuclear physics postdoctoral researcher at The DOE’s Lawrence Berkeley National Laboratory in Berkeley, California. She began work on the experiment as a graduate student at the University of New Hampshire. Li said the experiment was designed to compare fleeting partnerships between protons and neutrons-called “short range correlations”-in small nuclei.

    Protons and neutrons are collectively called nucleons. When nucleons are involved in short-range correlations, they briefly overlap before they fly apart with high momentum. Correlations may form between a proton and a neutron or between two protons or between two neutrons.

    This experiment compared the prevalence of each type of short-range correlation in the so-called mirror nuclei of helium-3 and tritium, an isotope of hydrogen. These nuclei each contain three nucleons. They are considered “mirror nuclei” because each one’s proton content mirrors the other’s neutron content.

    “Tritium is one proton and two neutrons, and helium-3 is two protons and one neutron. By comparing tritium and helium-3, we can assume that neutron-proton pairs in tritium are the same as neutron-proton pairs in helium- 3. And tritium can make one additional neutron-neutron pair, and helium-3 can make one additional proton-proton pair,” Li explained.

    Taken together, the data from both nuclei reveal how often nucleons pair up with others like themselves versus those that are different.

    “The simple idea is just to compare how many pairs the two nuclei have in each configuration,” she said.

    The researchers expected to see a result similar to earlier studies, which found that nucleons prefer pairing up by more than 20 to 1 with a different type (e.g. protons paired up with neutrons 20 times for every one time they paired up with another proton). These studies were conducted in heavier nuclei with far more protons and neutrons available for pairing, such as carbon, iron and lead.

    “The ratio we extracted in this experiment is four neutron-proton pairs per each proton-proton or neutron-neutron pair,” Li revealed.

    According to John Arrington, a spokesperson for the experiment and staff scientist at Berkeley Lab, this surprising result is providing new insight into the interactions between protons and neutrons in nuclei.

    “So in this case, we find that the proton-proton contribution is much, much bigger than expected. So it raises some questions about what’s different here,” he said.

    One idea is that the interactions between nucleons is a driver of this difference, and these interactions are modified somewhat by the distance between the nucleons in tritium versus helium-3 versus very large nuclei.

    “In the nucleon-nucleon interaction, there’s the “tensor” piece, which generates neutron-proton pairs. And there’s a shorter-range “core” that can generate proton-proton pairs. When the nucleons are further apart, as in these very light nuclei, you may get a different balance between these interactions.”

    Differences in the average distances between would-be correlated nucleons can have a strong influence on which particles they pick to pair with in an overlapping short-range correlation. For reference, a proton measures a little less than a femtometer, or fermi, wide. The longer-distance, tensor piece of the short-range interaction dominates as the particles overlap on the order of one-half fermi, or about a half-particle overlap. The shorter-range core part of the interaction dominates as the particles mostly overlap at one fermi.

    He says further research on this topic will help test this idea. In the meantime, the researchers are exploring whether the result will impact other measurements. For instance, in deep inelastic scattering experiments, nuclear physicists use short distance, hard collisions to explore nucleons’ structure.

    “We are pushing the precision in experiments on nuclear structure, and so these seemingly small effects can become very important as we continue to produce high-precision results at Jefferson Lab,” said Douglas Higinbotham, a spokesperson for the experiment and Jefferson Lab staff scientist. “So, if the nuclear effects are not only persistent but unexpected in the light nuclei, that means you can have unexpected things going on in your deep inelastic scattering results.”

    Arrington agreed.

    “We’re still making new measurements in familiar nuclei that are relevant to the nuclear structure and finding surprises. So the fact that we’re still finding surprises on a simple nucleus is very interesting,” Arrington commented. “We really want to understand where it comes from, because it has to tell us something about the way that the nucleons interact at short distance, which is hard to measure anywhere other than Jefferson Lab.”

    This experiment was conducted in Jefferson Lab’s Continuous Electron Beam Accelerator Facility (CEBAF)[below], an Office of Science user facility, in its Experimental Hall A. It featured a unique tritium target that was designed for a series of rare experiments, and it used a different tactic to capture a dataset that is a factor of 10 more precise than earlier experiments: measuring just the electrons that bounced off of a correlated nucleon inside the mirror nuclei.

    “Because of looking at tritium and helium-3, we were able to use inclusive scattering, and that gives us much higher statistics than other measurements. It’s a very unique chance, and a great design, and a lot of effort from the tritium project to get this result,” Li added.

    The nuclear physicists want to follow up this intriguing result with additional measurements in heavier nuclei. The earlier experiments in these nuclei used high-energy electrons generated in CEBAF. The electrons bounced from protons or neutrons engaged in a short-range correlation and the “the triple coincidence” of the outgoing electron, knocked-out proton and correlated partner was measured.

    One challenge for this type of two-nucleon short-range correlation measurement is catching all three particles. Yet, it’s hoped that future measurements will be able to capture three-nucleon short-range correlations for an even more detailed view of what is happening inside the nucleus.

    In the near-term, Arrington is a co-spokesperson on another experiment that is gearing up for additional short-range correlations measurements at CEBAF. The experiment will measure correlations in a range of light nuclei, including isotopes of helium, lithium, beryllium, and boron, as well as a number of heavier targets that vary in their neutron-to-proton ratio.

    Science paper:
    Nature
    See the full article for further reading suggestions.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    JLab campus
    DOE’s Thomas Jefferson National Accelerator Facility is supported by The Office of Science of the U.S. Department of Energy. DOE’s Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, visit science.energy.gov.

    Jefferson Science Associates, LLC, a joint venture of the Southeastern Universities Research Association, Inc. and PAE Applied Technologies, manages and operates the Thomas Jefferson National Accelerator Facility for the U.S. Department of Energy’s Office of Science.

    History

    DOE’s Thomas Jefferson National Accelerator Facility was established in 1984 (first initial funding by DOE, Department of Energy) as the Continuous Electron Beam Accelerator Facility (CEBAF); the name was changed to Thomas Jefferson National Accelerator Facility in 1996. The full funding for construction was appropriated by US Congress in 1986 and on February 13, 1987, the construction of the main component, the CEBAF accelerator begun. First beam was delivered to experimental area on 1 July 1994. The design energy of 4 GeV for the beam was achieved during the year 1995. The laboratory dedication took place 24 May 1996 (at this event the name was also changed). Full initial operations with all three initial experiment areas online at the design energy was achieved on June 19, 1998. On August 6, 2000 the CEBAF reached “enhanced design energy” of 6 GeV. In 2001, plans for an energy upgrade to 12 GeV electron beam and plans to construct a fourth experimental hall area started. The plans progressed through various DOE Critical Decision-stages in the 2000s decade, with the final DOE acceptance in 2008 and the construction on the 12 GeV upgrade beginning in 2009. May 18, 2012 the original 6 GeV CEBAF accelerator shut down for the replacement of the accelerator components for the 12 GeV upgrade. 178 experiments were completed with the original CEBAF.

    In addition to the accelerator, the laboratory has housed and continues to house a free electron laser (FEL) instrument.

    The construction of the FEL started 11 June 1996. It achieved first light on June 17, 1998. Since then, the FEL has been upgraded numerous times, increasing its power and capabilities substantially.

    Jefferson Lab was also involved in the construction of the Spallation Neutron Source (SNS) at DOE’s Oak Ridge National Laboratory . Jefferson built the SNS superconducting accelerator and helium refrigeration system. The accelerator components were designed and produced 2000–2005.

    Accelerator

    The laboratory’s main research facility is the CEBAF accelerator, which consists of a polarized electron source and injector and a pair of superconducting RF linear accelerators that are 7/8-mile (1400 m) in length and connected to each other by two arc sections that contain steering magnets.

    As the electron beam makes up to five successive orbits, its energy is increased up to a maximum of 6 GeV (the original CEBAF machine worked first in 1995 at the design energy of 4 GeV before reaching “enhanced design energy” of 6 GeV in 2000; since then, the facility has been upgraded into 12 GeV energy). This leads to a design that appears similar to a racetrack when compared to the classical ring-shaped accelerators found at sites such as The European Organization for Nuclear Research [La Organización Europea para la Investigación Nuclear][Organization européenne pour la recherche nucléaire] [Europäische Organisation für Kernforschung](CH)[CERN] or DOE’s Fermi National Accelerator Laboratory. Effectively, CEBAF is a linear accelerator, similar to DOE’s SLAC National Accelerator Laboratory at Stanford University, that has been folded up to a tenth of its normal length.

    The design of CEBAF allows the electron beam to be continuous rather than the pulsed beam typical of ring-shaped accelerators. (There is some beam structure, but the pulses are very much shorter and closer together.) The electron beam is directed onto three potential targets (see below). One of the distinguishing features of Jefferson Lab is the continuous nature of the electron beam, with a bunch length of less than 1 picosecond. Another is Jefferson Lab’s use of superconducting Radio Frequency (SRF) technology, which uses liquid helium to cool niobium to approximately 4 K (−452.5 °F), removing electrical resistance and allowing the most efficient transfer of energy to an electron. To achieve this, Jefferson Lab houses the world’s largest liquid helium refrigerator, and it was one of the first large-scale implementations of SRF technology. The accelerator is built 8 meters below the Earth’s surface, or approximately 25 feet, and the walls of the accelerator tunnels are 2 feet thick.

    The beam ends in four experimental halls, labelled Hall A, Hall B, Hall C, and Hall D. Each hall contains specialized spectrometers to record the products of collisions between the electron beam or with real photons and a stationary target. This allows physicists to study the structure of the atomic nucleus, specifically the interaction of the quarks that make up protons and neutrons of the nucleus.

    With each revolution around the accelerator, the beam passes through each of the two LINAC accelerators, but through a different set of bending magnets in semi-circular arcs at the ends of the linacs. The electrons make up to five passes through the linear accelerators.

    When a nucleus in the target is hit by an electron from the beam, an “interaction”, or “event”, occurs, scattering particles into the hall. Each hall contains an array of particle detectors that track the physical properties of the particles produced by the event. The detectors generate electrical pulses that are converted into digital values by analog-to-digital converters (ADCs), time to digital converters (TDCs) and pulse counters (scalers).

    This digital data is gathered and stored so that the physicist can later analyze the data and reconstruct the physics that occurred. The system of electronics and computers that perform this task is called a data acquisition system.

    12 GeV upgrade

    As of June 2010, construction began on a $338 million upgrade to add an end station, Hall D, on the opposite end of the accelerator from the other three halls, as well as to double beam energy to 12 GeV. Concurrently, an addition to the Test Lab, (where the SRF cavities used in CEBAF and other accelerators used worldwide are manufactured) was constructed.

    As of May 2014, the upgrade achieved a new record for beam energy, at 10.5 GeV, delivering beam to Hall D.

    As of December 2016, the CEBAF accelerator delivered full-energy electrons as part of commissioning activities for the ongoing 12 GeV Upgrade project. Operators of the Continuous Electron Beam Accelerator Facility delivered the first batch of 12 GeV electrons (12.065 Giga electron Volts) to its newest experimental hall complex, Hall D.

    In September 2017, the official notification from the DOE of the formal approval of the 12 GeV upgrade project completion and start of operations was issued. By spring 2018, all fours research areas were successfully receiving beam and performing experiments. On 2 May 2018 the CEBAF 12 GeV Upgrade Dedication Ceremony took place.

    As of December 2018, the CEBAF accelerator delivered electron beams to all four experimental halls simultaneously for physics-quality production running.

     
  • richardmitnick 9:48 pm on August 2, 2022 Permalink | Reply
    Tags: "The Strength of the Strong Force", A mechanism that accounts for 99 percent of the ordinary mass in the universe, , Jefferson Lab experiments hone in on a never-before-measured region of strong force coupling-a quantity that supports theories accounting for 99% of the ordinary mass in the universe., , , , The DOE's Thomas Jefferson National Accelerator Facility, The flattening of the strong force coupling at large distances provides evidence that physicists can apply a new cutting-edge technique called Anti-de Sitter/Conformal Field Theory (AdS/CFT) duality., The scientists extracted this value of the strong force from a handful of Jefferson Lab experiments that were actually designed to study something completely different: proton and neutron spin., These results are a true breakthrough for the advancement of quantum chromodynamics and hadron physics., With Jefferson Lab data the physicists were able to determine the strong force coupling at the largest distances yet.   

    From The DOE’s Thomas Jefferson National Accelerator Facility : “The Strength of the Strong Force” 

    From The DOE’s Thomas Jefferson National Accelerator Facility

    8.2.22
    Written by Chris Patrick

    Kandice Carter
    Jefferson Lab Communications Office
    kcarter@jlab.org

    Jefferson Lab experiments hone in on a never-before-measured region of strong force coupling-a quantity that supports theories accounting for 99% of the ordinary mass in the universe.

    Much ado was made about the Higgs boson when this elusive particle was discovered in 2012. Though it was touted as giving ordinary matter mass, interactions with the Higgs field only generate about 1 percent of ordinary mass. The other 99 percent comes from phenomena associated with the strong force, the fundamental force that binds smaller particles called quarks into larger particles called protons and neutrons that comprise the nucleus of the atoms of ordinary matter.

    Now, researchers at the U.S. Department of Energy’s Thomas Jefferson National Accelerator Facility have experimentally extracted the strength of the strong force, a quantity that firmly supports theories explaining how most of the mass or ordinary matter in the universe is generated.

    This quantity, known as the coupling of the strong force, describes how strongly two bodies interact or “couple” under this force. Strong force coupling varies with distance between the particles affected by the force. Prior to this research, theories disagreed on how strong force coupling should behave at large distance: some predicted it should grow with distance, some that it should decrease, and some that it should become constant.

    With Jefferson Lab data the physicists were able to determine the strong force coupling at the largest distances yet. Their results, which provide experimental support for theoretical predictions, were recently featured on the cover of the journal Particles [paper is below].

    1

    “We are happy and excited to see our effort get recognized,” said Jian-Ping Chen, senior staff scientist at Jefferson Lab and a co-author of the paper.

    Though this paper is the culmination of years of data collection and analysis, it wasn’t entirely intentional at first.

    A spinoff of a spin experiment

    At smaller distances between quarks, strong force coupling is small, and physicists can solve for it with a standard iterative method. At larger distances, however, strong force coupling becomes so big that the iterative method doesn’t work anymore.

    “This is both a curse and a blessing,” said Alexandre Deur, a staff scientist at Jefferson Lab and a co-author of the paper. “While we have to use more complicated techniques to compute this quantity, its sheer value unleashes a host of very important emerging phenomena.”

    This includes a mechanism that accounts for 99 percent of the ordinary mass in the universe. (But we’ll get to that in a bit.)

    Despite the challenge of not being able to use the iterative method, Deur, Chen and their co-authors extracted strong force coupling at the largest distances between affected bodies ever.

    They extracted this value from a handful of Jefferson Lab experiments that were actually designed to study something completely different: proton and neutron spin.

    These experiments were conducted in the lab’s Continuous Electron Beam Accelerator Facility [below], a DOE user facility. CEBAF is capable of providing polarized electron beams, which can be directed onto specialized targets containing polarized protons and neutrons in the experimental halls. When an electron beam is polarized, that means that a majority of the electrons are all spinning in the same direction.

    These experiments shot Jefferson Lab’s polarized electron beam at polarized proton or neutron targets. During the several years of data analysis afterward, the researchers realized they could combine information gathered about the proton and neutron to extract strong force coupling at larger distances.

    “Only Jefferson Lab’s high-performance polarized electron beam, in combination with developments in polarized targets and detection systems allowed us to get such data,” Chen said.

    They found that as distance increases between affected bodies, strong force coupling grows quickly before leveling off and becoming constant.

    “There are some theories that predicted that this should be the case, but this is the first time experimentally that we actually saw this,” Chen said. “This gives us detail on how the strong force, at the scale of the quarks forming protons and neutrons, actually works.”

    Leveling off supports massive theories

    These experiments were conducted about 10 years ago, when Jefferson Lab’s electron beam was capable of providing electrons at up to 6 GeV in energy (it’s now capable of up to 12 GeV). The lower-energy electron beam was required to examine the strong force at these larger distances: a lower-energy probe allows access to longer time scales and, therefore, larger distances between affected particles.

    Similarly, a higher-energy probe is essential for zooming in for views of shorter timescales and smaller distances between particles. Labs with higher-energy beams, such as CERN, Fermi National Accelerator Laboratory, and SLAC National Accelerator Laboratory, have already examined strong force coupling at these smaller spacetime scales, when this value is relatively small.

    The zoomed-in view offered by higher-energy beams has shown that mass of a quark is small, only a few MeV. At least, that’s their textbook mass. But when quarks are probed with lower energy, their mass effectively grows to 300 MeV.

    This is because the quarks gather a cloud of gluons, the particle that carries the strong force, as they move across larger distances. The mass-generating effect of this cloud accounts for most of the mass in the universe – without this additional mass, the textbook mass of quarks can only account for about 1% of the mass of protons and neutrons. The other 99% comes from this acquired mass.

    Similarly, a theory posits that gluons are massless at short distances but effectively acquire mass as they travel further. The leveling of strong force coupling at large distances supports this theory.

    “If gluons remained massless at long range, strong force coupling would keep growing unchecked,” Deur said. “Our measurements show that strong force coupling becomes constant as the distance probed gets larger, which is a sign that gluons have acquired mass through the same mechanism that gives 99% of mass to the proton and the neutron.”

    This means strong force coupling at large distances is important for understanding this mass generation mechanism. These results also help verify new ways to solve equations for quantum chromodynamics (QCD), the accepted theory describing the strong force.

    For instance, the flattening of the strong force coupling at large distances provides evidence that physicists can apply a new cutting-edge technique called Anti-de Sitter/Conformal Field Theory (AdS/CFT) duality. The AdS/CFT technique allows physicists to solve equations non-iteratively, which can help with strong force calculations at large distances where iterative methods fail.

    The conformal in “Conformal Field Theory” means the technique is based on a theory that behaves the same at all spacetime scales. Because strong force coupling levels off at larger distances, it is no longer dependent on spacetime scale, meaning the strong force is conformal and AdS/CFT can be applied. While theorists have already been applying AdS/CFT to QCD, this data supports use of the technique.

    “AdS/CFT has allowed us to solve problems of QCD or quantum gravity that were hitherto intractable or addressed very roughly using not very rigorous models,” Deur said. “This has yielded many exciting insights into fundamental physics.”

    So, while these results were generated by experimentalists, they affect theorists the most.

    “I believe that these results are a true breakthrough for the advancement of quantum chromodynamics and hadron physics,” said Stanley Brodsky, emeritus professor at The DOE’s SLAC National Accelerator Laboratory and a QCD theorist. “I congratulate the Jefferson Lab physics community, particularly, Dr. Alexandre Deur, for this major advance in physics.”

    Years have passed since the experiments that accidentally bore these results were conducted. A whole new suite of experiments now use Jefferson Lab’s higher energy 12 GeV beam to explore nuclear physics.

    “One thing I’m very happy about with all these older experiments is that we trained many young students and they have now become leaders of future experiments,” Chen said.

    Only time will tell which theories these new experiments support.

    Science paper:
    Particles

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    JLab campus
    DOE’s Thomas Jefferson National Accelerator Facility is supported by The Office of Science of the U.S. Department of Energy. DOE’s Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, visit science.energy.gov.

    Jefferson Science Associates, LLC, a joint venture of the Southeastern Universities Research Association, Inc. and PAE Applied Technologies, manages and operates the Thomas Jefferson National Accelerator Facility for the Department of Energy’s Office of Science.

    History

    DOE’s Thomas Jefferson National Accelerator Facility was established in 1984 (first initial funding by DOE, Department of Energy) as the Continuous Electron Beam Accelerator Facility (CEBAF); the name was changed to Thomas Jefferson National Accelerator Facility in 1996. The full funding for construction was appropriated by US Congress in 1986 and on February 13, 1987, the construction of the main component, the CEBAF accelerator begun. First beam was delivered to experimental area on 1 July 1994. The design energy of 4 GeV for the beam was achieved during the year 1995. The laboratory dedication took place 24 May 1996 (at this event the name was also changed). Full initial operations with all three initial experiment areas online at the design energy was achieved on June 19, 1998. On August 6, 2000 the CEBAF reached “enhanced design energy” of 6 GeV. In 2001, plans for an energy upgrade to 12 GeV electron beam and plans to construct a fourth experimental hall area started. The plans progressed through various DOE Critical Decision-stages in the 2000s decade, with the final DOE acceptance in 2008 and the construction on the 12 GeV upgrade beginning in 2009. May 18, 2012 the original 6 GeV CEBAF accelerator shut down for the replacement of the accelerator components for the 12 GeV upgrade. 178 experiments were completed with the original CEBAF.

    In addition to the accelerator, the laboratory has housed and continues to house a free electron laser (FEL) instrument. The construction of the FEL started 11 June 1996. It achieved first light on June 17, 1998. Since then, the FEL has been upgraded numerous times, increasing its power and capabilities substantially.

    Jefferson Lab was also involved in the construction of the Spallation Neutron Source (SNS) at The DOE’s Oak Ridge National Laboratory . Jefferson built the SNS superconducting accelerator and helium refrigeration system. The accelerator components were designed and produced 2000–2005.

    Accelerator

    The laboratory’s main research facility is the CEBAF accelerator, which consists of a polarized electron source and injector and a pair of superconducting RF linear accelerators that are 7/8-mile (1400 m) in length and connected to each other by two arc sections that contain steering magnets.

    As the electron beam makes up to five successive orbits, its energy is increased up to a maximum of 6 GeV (the original CEBAF machine worked first in 1995 at the design energy of 4 GeV before reaching “enhanced design energy” of 6 GeV in 2000; since then, the facility has been upgraded into 12 GeV energy). This leads to a design that appears similar to a racetrack when compared to the classical ring-shaped accelerators found at sites such as The European Organization for Nuclear Research [La Organización Europea para la Investigación Nuclear][Organisation européenne pour la recherche nucléaire] [Europäische Organisation für Kernforschung](CH)[CERN] or DOE’s Fermi National Accelerator Laboratory. Effectively, CEBAF is a linear accelerator, similar to DOE’s SLAC National Accelerator Laboratory at Stanford University, that has been folded up to a tenth of its normal length.

    The design of CEBAF allows the electron beam to be continuous rather than the pulsed beam typical of ring-shaped accelerators. (There is some beam structure, but the pulses are very much shorter and closer together.) The electron beam is directed onto three potential targets (see below). One of the distinguishing features of Jefferson Lab is the continuous nature of the electron beam, with a bunch length of less than 1 picosecond. Another is Jefferson Lab’s use of superconducting Radio Frequency (SRF) technology, which uses liquid helium to cool niobium to approximately 4 K (−452.5 °F), removing electrical resistance and allowing the most efficient transfer of energy to an electron. To achieve this, Jefferson Lab houses the world’s largest liquid helium refrigerator, and it was one of the first large-scale implementations of SRF technology. The accelerator is built 8 meters below the Earth’s surface, or approximately 25 feet, and the walls of the accelerator tunnels are 2 feet thick.

    The beam ends in four experimental halls, labelled Hall A, Hall B, Hall C, and Hall D. Each hall contains specialized spectrometers to record the products of collisions between the electron beam or with real photons and a stationary target. This allows physicists to study the structure of the atomic nucleus, specifically the interaction of the quarks that make up protons and neutrons of the nucleus.

    With each revolution around the accelerator, the beam passes through each of the two LINAC accelerators, but through a different set of bending magnets in semi-circular arcs at the ends of the linacs. The electrons make up to five passes through the linear accelerators.

    When a nucleus in the target is hit by an electron from the beam, an “interaction”, or “event”, occurs, scattering particles into the hall. Each hall contains an array of particle detectors that track the physical properties of the particles produced by the event. The detectors generate electrical pulses that are converted into digital values by analog-to-digital converters (ADCs), time to digital converters (TDCs) and pulse counters (scalers).

    This digital data is gathered and stored so that the physicist can later analyze the data and reconstruct the physics that occurred. The system of electronics and computers that perform this task is called a data acquisition system.

    12 GeV upgrade

    As of June 2010, construction began on a $338 million upgrade to add an end station, Hall D, on the opposite end of the accelerator from the other three halls, as well as to double beam energy to 12 GeV. Concurrently, an addition to the Test Lab, (where the SRF cavities used in CEBAF and other accelerators used worldwide are manufactured) was constructed.

    As of May 2014, the upgrade achieved a new record for beam energy, at 10.5 GeV, delivering beam to Hall D.

    As of December 2016, the CEBAF accelerator delivered full-energy electrons as part of commissioning activities for the ongoing 12 GeV Upgrade project. Operators of the Continuous Electron Beam Accelerator Facility delivered the first batch of 12 GeV electrons (12.065 Giga electron Volts) to its newest experimental hall complex, Hall D.

    In September 2017, the official notification from the DOE of the formal approval of the 12 GeV upgrade project completion and start of operations was issued. By spring 2018, all fours research areas were successfully receiving beam and performing experiments. On 2 May 2018 the CEBAF 12 GeV Upgrade Dedication Ceremony took place.

    As of December 2018, the CEBAF accelerator delivered electron beams to all four experimental halls simultaneously for physics-quality production running.

     
  • richardmitnick 11:15 am on March 4, 2022 Permalink | Reply
    Tags: "The Electron-Ion Collider-A Precision Tool for Studying the 'Glue' that Binds Visible Matter", , An international community of physicists outlined the parameters of a machine that could embark on an exploration of a new frontier in nuclear physics., , , CGC: Color Glass Condensate, Consensus called for construction of a high-intensity high-energy electron-ion collider with controlled spin orientation of particles in the colliding beams., Despite more than six decades of exploration our knowledge of quark confinement and asymptotic freedom within protons are surprisingly insufficient compared with our understanding of electromagnetism., EIC scientists would like to build two complementary detectors so they can collect different kinds of data and/or cross-check one another’s findings., , Measurements from past experiments have shown that gluon number density inside nuclei increases at high energy., One could assume that this abundance of particles would explain where protons get their mass but quarks are nearly massless and gluons have no mass., , , , Quarks and gluons also have a property called spin – a form of intrinsic angular momentum., Since the 1960s physicists have known that protons and neutrons are made up of fundamental particles called quarks bound together by a force resulting from the exchange of gluons., The "strong force", The Brookhaven collider complex has two interaction regions for large-scale EIC detectors., The DOE's Thomas Jefferson National Accelerator Facility, , The EIC project within the DOE Office of Science includes funding for the accelerators; one interaction region and one detector., The EIC will use the existing tunnel of the Relativistic Heavy Ion Collider (RHIC) at Brookhaven Lab along with one of its existing ion accelerator rings., The Electron-Ion Collider will peer into protons and neutrons-the building blocks that make up atomic nuclei., The strong force depends on the existence of a different type of charge called the "color charge"., The strong force seems to have three types called "colors" (red blue and green)., We need to pin down the gluon and understand its gluelike behaviour much more precisely.   

    From The DOE’s Brookhaven National Laboratory (US): “The Electron-Ion Collider-A Precision Tool for Studying the ‘Glue’ that Binds Visible Matter” 

    From The DOE’s Brookhaven National Laboratory (US)

    March 4, 2022
    Abhay Deshpande, Stony Brook University
    Zein-Eddine Meziani, DOE’s Argonne National Laboratory

    Professor Abhay Deshpande, of Stony Brook University and Brookhaven National Laboratory, and Dr Zein-Eddine Meziani, of Argonne National Laboratory, outline the potential of the planned Electron-Ion Collider and the many questions about the Universe that it hopes to answer.

    1

    The Electron-Ion Collider (EIC) [below], planned to be built at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory (BNL), in partnership with The DOE’s Thomas Jefferson National Accelerator Facility (Jefferson Lab), will be the most advanced tool for studying some of the deepest unexplored recesses of the atom.

    It will peer into protons and neutrons-the building blocks that make up atomic nuclei, providing unprecedented insight into how those particles’ internal building blocks—and the gluelike force that holds them together – build up the structure of nearly all visible matter in the Universe.

    The quark structure of the proton. 16 March 2006 Arpad Horvath.

    The quark structure of the neutron. 15 January 2018 Jacek Rybak.

    Electron-Ion Collider Science: Origin of mass

    We know that a proton is made up of quarks and a sea of gluons (see box). Those gluons also keep producing quarks and anti-quark pairs (called sea-quarks). So, the internal microcosm of a proton is abundantly full. One could assume that this abundance of particles would explain where protons get their mass but quarks are nearly massless and gluons have no mass. If we add up the masses of the quarks that make up the proton, they account for only about 1% of the proton’s total mass.

    Where is the remaining 99%? Astonishingly, it appears to come from the interaction energy among the proton’s inner building blocks. In fact, it looks like the nucleons, nuclei and, by extension, all the planets and galaxies of the visible Universe get their mass through interactions of massless gluons and almost massless quarks. How does this happen? The Electron-Ion Collider will resolve this profound and longstanding mystery.

    2
    Fig 1: The sum of the mass of the particles that make up a proton – quarks (large colored spheres), gluons (yellow squiggles), and quark-antiquark pairs (smaller spheres) – comes to 1.8 x 10-26 g, while the proton containing those particles and their interactions weighs almost 100 times more. EIC may reveal exactly how the quark-gluon interactions generate the bulk of a proton’s mass.

    Since the 1960s physicists have known that protons and neutrons, referred to collectively as nucleons, are made up of fundamental particles called quarks bound together by a force resulting from the exchange of gluons. We call this the “strong force”. The strong force depends on the existence of a different type of charge called the “color charge”. Unlike “electric charge”, which comes in two varieties (positive and negative), the strong force seems to have three types called “colors” (red; blue and green).

    Another important difference is that, unlike the photons that mediate the electromagnetic force, the gluons that mediate the strong force can and do interact with one another. That is one of the characteristics that makes the strong force so strong. In fact, it makes it impossible to find a free quark in nature. Instead, quarks are always confined within composite particles such as protons. Within the protons, however, the quarks are essentially free to move around.

    Despite more than six decades of exploration, our knowledge and understanding of this apparent discrepancy between quark confinement and asymptotic freedom within protons, as well as the gluons’ role in strong force interactions, are surprisingly insufficient compared with our understanding of electromagnetism—the force at the heart of today’s electronic technologies. Can we do better? Yes, but for that we need to pin down the gluon and understand its gluelike behaviour much more precisely. For that, we need the EIC. What we learn may unlock the secrets of the strongest force in nature and potentially new ways to apply that knowledge.

    Electron-Ion Collider Science: Origin of spin

    3
    Fig 2: Protons and neutrons are made up of three valence quarks (shown as large colored spheres with arrows), a sea of gluons (yellow wiggles), and sea quarks (pairs of smaller colored quarks and antiquarks in the right figure). EIC will explore how these quark and gluon spins and their possible orbital motion generate the total spin of the proton.

    Quarks and gluons also have a property called spin – a form of intrinsic angular momentum. You can think of spin as similar to the rotation of Earth around its own axis, resulting in days and nights. Being part of the proton, which also has a definite ‘spin’, the quarks and gluons are naturally expected to contribute to the proton’s spin. However, experiments performed so far indicate that quark and gluon spins can explain only about 40-50% of the total spin of the proton.

    Scientists think that the remaining spin of the proton must come from the motion of the quarks and gluons inside the proton being aligned with the proton’s orbital angular momentum – which, in the case of Earth, would be the planet’s motion around the Sun. There is ample evidence of such transverse motion of quarks and gluons inside the proton, but only the EIC will be able to measure if that motion is consistent with the angular momentum. If true, a beautifully consistent picture may emerge, showing that the orbital motion explaining the spin of the nucleons also results in the energy of quarks and gluons, simultaneously explaining the mass of the proton.

    EIC Science: Gluon saturation

    Measurements from past experiments have shown that gluon number density inside nuclei increases at high energy. The theory that explains quark-gluon interactions can explain this increase. However, at extremely high energy, beyond what has been experimentally explored, certain fundamental rules and arguments of that theory and fundamental physics suggest that there is a cap on how high gluon density can rise.

    In such a regime, a novel state of saturated gluonic matter, called the Color Glass Condensate (CGC), is expected to be formed. Theoretical studies of CGC suggest that it should have some remarkably intriguing properties, including energy density as high or higher than that in the core of neutron stars, the densest objects in our Universe. Does such an exotic form of gluonic matter really exist? If so, what are its properties and how can we study them systematically? If CGC does not exist, then what unknown mechanism in physics puts a cap on the number of gluons at high energy? The Electron-Ion Collider will explore this mystery.

    The EIC moves forward

    5
    Fig 3: The number of gluons in the proton increases with energy. Theory predicts it must saturate to form a novel gluonic form of matter called the Color Glass Condensate. Discovery and detailed study of CGC is one of the primary goals of the EIC.

    Recognising the importance of understanding the origin of mass and spin and the potential for discovering and studying a saturated gluonic state in nucleons and nuclei, an international community of physicists outlined the parameters of a machine that could embark on an exploration of this new frontier in nuclear physics.

    The consensus called for construction of a high-intensity high-energy electron-ion collider with controlled spin orientation of particles in the colliding beams. A 2018 report from the US National Academy of Sciences, Engineering and Medicine (NAS) concluded that the “EIC science is compelling, fundamental and timely.” In January 2020, the U.S. Department of Energy (DOE) announced that the facility would be built at Brookhaven National Laboratory in New York. A recent review set the cost range for the EIC to be $1.7-2.8bn from the DOE Office of Science, with anticipated contribution of $100m from New York State.

    A team of physicists, technicians, engineers, and other professionals from Brookhaven Lab and Jefferson Lab, as well as other collaborating partners from around the world, is now working to make the EIC a reality. The team hopes to start construction in 2024, aiming for a collider operation date within the 2030s.

    The EIC will have the below main features:

    6
    Fig 4: The EIC will use the existing tunnel of the Relativistic Heavy Ion Collider (RHIC), currently operating as a DOE Office of Science user facility for nuclear physics research at Brookhaven Lab, along with one of its existing ion accelerator rings (shown in yellow). A new electron beam facility (red and cyan) will be built to inject, accelerate, store, and collide electrons with ions — atomic nuclei stripped of their electrons — at two possible detector locations. The ion beams will be prepared at the ion source and accelerated through an existing chain of accelerators (green), including the booster and the Alternating Gradient Synchrotron (AGS)[below].

    High luminosity: The EIC will produce particle collisions at a rate of 1 × 1034 per square centimetre per second. Lots of collisions (also referred to as high luminosity) means lots of data.

    High polarization: Both the electrons and some ion beams will be polarized, making the EIC the only facility in the world with this capability. This means the particles’ spins can be aligned in a particular way. EIC physicists will collide polarized particles to study how the spins and orbital motion of their internal building blocks contribute to their overall spin.

    High energy: The EIC will produce collisions at variable center-of-mass energies, from 20 billion to 140 billion electron volts (GeV). At the scale of ordinary things, that is less energy than two mosquitoes colliding. But, at the scale of an electron colliding with a proton, it is enough to produce high-resolution snapshots of the proton’s internal components.

    Varied ion species: The ion sources for the EIC, already in use at the Relativistic Heavy Ion Collider (RHIC) and the adjacent NASA Space Radiation Laboratory, can provide ions of almost any element on the periodic table. Light ion beams (protons, deuterons, and helium-3) will emerge polarized from their source. EIC scientists will use a wide range of beams, from protons to heavy ions, to explore how ion size and other features of nuclei affect properties and interactions of quarks and gluons.

    Designing EIC detectors

    Scientists around the world are also working to design detector systems that will make the most of the EIC’s technical capabilities. The EIC Users Group (EICUG) was formally established in 2016 and has been actively working with the Brookhaven Lab and Jefferson Lab management teams and with the DOE on plans. Starting with about 700 scientists, the group has now grown to more than 1,300 participants from over 250 institutions and 33 countries. By the time the EIC is ready for operations, some 2,000 scientists are expected to conduct experiments.

    The EIC Project Management team issued a call for detector collaboration proposals in February 2021. This call formally launched the process of refining detector designs and the formation of experimental collaborations. Three teams submitted detailed plans, now under review by an external committee appointed by the Brookhaven Lab and Jefferson Lab management teams.

    Ideally, EIC scientists would like to build two complementary detectors so they can collect different kinds of data and/or cross-check one another’s findings. The Brookhaven collider complex has two interaction regions for such large-scale EIC detectors. The EIC project within the DOE Office of Science includes funding for the accelerators; one interaction region and one detector.

    7
    Fig. 5: An ideal EIC detector, as envisioned in an EIC User Group report, includes subdetector systems for tracking and identifying various types of particles and measuring characteristics such as their energy and momentum.

    As part of the Electron-Ion Collider team’s collaboration-building strategy, the project team and user group are working to attract additional funding sources, including international and non-DOE funds. Some of this additional non-DOE-sourced funding could potentially be used to build a complementary detector system in the second interaction region to maximise the scientific output of the EIC complex. The EIC project stands ready to explore all such possibilities and would welcome any such initiative for collaboration from around the world.

    Societal benefits

    The EIC will be one of the world’s most complex accelerator projects ever designed and operated. The versatility and flexibility in its operation make the EIC a challenging but exciting machine to work on. Physicists and engineers involved in the project will be developing many state-of-the-art (or beyond) accelerator technologies to make this machine a reality over the next several years. Such a challenging endeavour will attract the world’s most talented and ambitious accelerator scientists. Collaborations are being initiated with leading national and international accelerator laboratories to contribute and participate in the EIC design. Similar international cooperation is expected to emerge once detector construction begins and when the EIC becomes operational.

    Such a concentrated effort to design and develop new technologies will likely spark innovations that have impacts well beyond the field of nuclear physics. Cancer therapy is one example. The particle-beam-related improvements for the EIC could lead to improved delivery and quality of particle beams used to treat cancer with reduced cost and improved efficiency and efficacy.

    8
    Fig. 6: Map of institutions that form the EIC Users Group. Current membership stands at over 1,300 scientists from more than 250 institutions and 33 countries.

    Another potential impact could be improvements to accelerators used in industry – for example, to test computer chips, study new materials for batteries and solar cells, and develop alternative and clean energy technologies. These improvements would also benefit the biomedical industry, where accelerators are used to study different kinds of proteins, including for drug and vaccine development, and for inspecting and keeping our food supply safe.

    The research and development (R&D) anticipated for Electron-Ion Collider detector components will also push the evolution of technologies and bring in new ideas that could be directly exported for use in security operations, for example to identify illicit drugs in closed cargo containers or to identify other national security (sensitive) materials.

    In addition, the EIC’s need for highly efficient data collection, storage, and analysis will spark advances in computing that extend to other fields, including finance, climate modelling, and other data-intensive challenges.

    Finally, and perhaps most importantly, by attracting the best science, technology, engineering, and mathematics (STEM) workforce from around the world to build and run the EIC, we will be building up a tech-savvy workforce for tomorrow while also building bridges that connect nations of the world.

    Students and researchers from different nationalities and cultures will come together to work on some of the most challenging conceptual and technical problems in nuclear and particle science and on accelerator and detector technologies—while also learning about one another. In the long run, through those collaborations, they could become ambassadors of peace and friendship among countries and cultures across the world. The tools, technologies, and connections they develop will benefit mankind for many decades to come.

    See the full article here .


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    Please help promote STEM in your local schools.

    Stem Education Coalition

    Brookhaven Campus

    One of ten national laboratories overseen and primarily funded by the The DOE(US) Office of Science, The DOE’s Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. The Laboratory’s almost 3,000 scientists, engineers, and support staff are joined each year by more than 5,000 visiting researchers from around the world. Brookhaven is operated and managed for DOE’s Office of Science by Brookhaven Science Associates, a limited-liability company founded by Stony Brook University(US the largest academic user of Laboratory facilities, and Battelle(US), a nonprofit, applied science and technology organization.

    Research at BNL specializes in nuclear and high energy physics, energy science and technology, environmental and bioscience, nanoscience and national security. The 5,300 acre campus contains several large research facilities, including the Relativistic Heavy Ion Collider [below] and National Synchrotron Light Source II [below]. Seven Nobel prizes have been awarded for work conducted at Brookhaven lab.

    BNL is staffed by approximately 2,750 scientists, engineers, technicians, and support personnel, and hosts 4,000 guest investigators every year. The laboratory has its own police station, fire department, and ZIP code (11973). In total, the lab spans a 5,265-acre (21 km^2) area that is mostly coterminous with the hamlet of Upton, New York. BNL is served by a rail spur operated as-needed by the New York and Atlantic Railway. Co-located with the laboratory is the Upton, New York, forecast office of the National Weather Service.

    Major programs

    Although originally conceived as a nuclear research facility, Brookhaven Lab’s mission has greatly expanded. Its foci are now:

    Nuclear and high-energy physics
    Physics and chemistry of materials
    Environmental and climate research
    Nanomaterials
    Energy research
    Nonproliferation
    Structural biology
    Accelerator physics

    Operation

    Brookhaven National Lab was originally owned by the Atomic Energy Commission(US) and is now owned by that agency’s successor, the United States Department of Energy (DOE). DOE subcontracts the research and operation to universities and research organizations. It is currently operated by Brookhaven Science Associates LLC, which is an equal partnership of Stony Brook University(US) and Battelle Memorial Institute(US). From 1947 to 1998, it was operated by Associated Universities, Inc. (AUI) (US), but AUI lost its contract in the wake of two incidents: a 1994 fire at the facility’s high-beam flux reactor that exposed several workers to radiation and reports in 1997 of a tritium leak into the groundwater of the Long Island Central Pine Barrens on which the facility sits.

    Foundations

    Following World War II, the US Atomic Energy Commission was created to support government-sponsored peacetime research on atomic energy. The effort to build a nuclear reactor in the American northeast was fostered largely by physicists Isidor Isaac Rabi and Norman Foster Ramsey Jr., who during the war witnessed many of their colleagues at Columbia University leave for new remote research sites following the departure of the Manhattan Project from its campus. Their effort to house this reactor near New York City was rivalled by a similar effort at the Massachusetts Institute of Technology (US) to have a facility near Boston, Massachusettes(US). Involvement was quickly solicited from representatives of northeastern universities to the south and west of New York City such that this city would be at their geographic center. In March 1946 a nonprofit corporation was established that consisted of representatives from nine major research universities — Columbia University(US), Cornell University(US), Harvard University(US), Johns Hopkins University(US), Massachusetts Institute of Technology(US), Princeton University(US), University of Pennsylvania(US), University of Rochester(US), and Yale University(US).

    Out of 17 considered sites in the Boston-Washington corridor, Camp Upton on Long Island was eventually chosen as the most suitable in consideration of space, transportation, and availability. The camp had been a training center from the US Army during both World War I and World War II. After the latter war, Camp Upton was deemed no longer necessary and became available for reuse. A plan was conceived to convert the military camp into a research facility.

    On March 21, 1947, the Camp Upton site was officially transferred from the U.S. War Department to the new U.S. Atomic Energy Commission (AEC), predecessor to the U.S. Department of Energy (DOE).

    Research and facilities

    Reactor history

    In 1947 construction began on the first nuclear reactor at Brookhaven, the Brookhaven Graphite Research Reactor. This reactor, which opened in 1950, was the first reactor to be constructed in the United States after World War II. The High Flux Beam Reactor operated from 1965 to 1999. In 1959 Brookhaven built the first US reactor specifically tailored to medical research, the Brookhaven Medical Research Reactor, which operated until 2000.

    Accelerator history

    In 1952 Brookhaven began using its first particle accelerator, the Cosmotron. At the time the Cosmotron was the world’s highest energy accelerator, being the first to impart more than 1 GeV of energy to a particle.

    BNL Cosmotron 1952-1966.

    The Cosmotron was retired in 1966, after it was superseded in 1960 by the new Alternating Gradient Synchrotron (AGS).

    BNL Alternating Gradient Synchrotron (AGS).

    The AGS was used in research that resulted in 3 Nobel prizes, including the discovery of the muon neutrino, the charm quark, and CP violation.

    In 1970 in BNL started the ISABELLE project to develop and build two proton intersecting storage rings.

    The groundbreaking for the project was in October 1978. In 1981, with the tunnel for the accelerator already excavated, problems with the superconducting magnets needed for the ISABELLE accelerator brought the project to a halt, and the project was eventually cancelled in 1983.

    The National Synchrotron Light Source (US) operated from 1982 to 2014 and was involved with two Nobel Prize-winning discoveries. It has since been replaced by the National Synchrotron Light Source II (US). [below].

    BNL National Synchrotron Light Source (US).

    After ISABELLE’S cancellation, physicist at BNL proposed that the excavated tunnel and parts of the magnet assembly be used in another accelerator. In 1984 the first proposal for the accelerator now known as the Relativistic Heavy Ion Collider (RHIC)[below] was put forward. The construction got funded in 1991 and RHIC has been operational since 2000. One of the world’s only two operating heavy-ion colliders, RHIC is as of 2010 the second-highest-energy collider after the Large Hadron Collider(CH). RHIC is housed in a tunnel 2.4 miles (3.9 km) long and is visible from space.

    On January 9, 2020, It was announced by Paul Dabbar, undersecretary of the US Department of Energy Office of Science, that the BNL eRHIC design has been selected over the conceptual design put forward by DOE’s Thomas Jefferson National Accelerator Facility [Jlab] (US) as the future Electron–ion collider (EIC) in the United States.

    Brookhaven Lab Electron-Ion Collider (EIC) (US) to be built inside the tunnel that currently houses the RHIC.

    In addition to the site selection, it was announced that the BNL EIC had acquired CD-0 from the Department of Energy. BNL’s eRHIC design proposes upgrading the existing Relativistic Heavy Ion Collider, which collides beams light to heavy ions including polarized protons, with a polarized electron facility, to be housed in the same tunnel.

    Other discoveries

    In 1958, Brookhaven scientists created one of the world’s first video games, Tennis for Two. In 1968 Brookhaven scientists patented Maglev, a transportation technology that utilizes magnetic levitation.

    Major facilities

    Relativistic Heavy Ion Collider (RHIC), which was designed to research quark–gluon plasma and the sources of proton spin. Until 2009 it was the world’s most powerful heavy ion collider. It is the only collider of spin-polarized protons.

    Center for Functional Nanomaterials (CFN), used for the study of nanoscale materials.

    BNL National Synchrotron Light Source II(US), Brookhaven’s newest user facility, opened in 2015 to replace the National Synchrotron Light Source (NSLS), which had operated for 30 years. NSLS was involved in the work that won the 2003 and 2009 Nobel Prize in Chemistry.

    Alternating Gradient Synchrotron, a particle accelerator that was used in three of the lab’s Nobel prizes.
    Accelerator Test Facility, generates, accelerates and monitors particle beams.
    Tandem Van de Graaff, once the world’s largest electrostatic accelerator.

    Computational Science resources, including access to a massively parallel Blue Gene series supercomputer that is among the fastest in the world for scientific research, run jointly by Brookhaven National Laboratory and Stony Brook University-SUNY (US).

    Interdisciplinary Science Building, with unique laboratories for studying high-temperature superconductors and other materials important for addressing energy challenges.
    NASA Space Radiation Laboratory, where scientists use beams of ions to simulate cosmic rays and assess the risks of space radiation to human space travelers and equipment.

    Off-site contributions

    It is a contributing partner to the ATLAS experiment, one of the four detectors located at the Large Hadron Collider (LHC).

    The European Organization for Nuclear Research [La Organización Europea para la Investigación Nuclear][Organisation européenne pour la recherche nucléaire] [Europäische Organisation für Kernforschung](CH)[CERN] map.

    Iconic view of the European Organization for Nuclear Research [La Organización Europea para la Investigación Nuclear] [Organisation européenne pour la recherche nucléaire] [Europäische Organisation für Kernforschung](CH) [CERN] ATLAS detector.

    It is currently operating at The European Organization for Nuclear Research [La Organización Europea para la Investigación Nuclear][Organisation européenne pour la recherche nucléaire] [Europäische Organisation für Kernforschung](CH) [CERN] near Geneva, Switzerland.

    Brookhaven was also responsible for the design of the SNS accumulator ring in partnership with Spallation Neutron Source at DOE’s Oak Ridge National Laboratory (US), Tennessee.

    DOE’s Oak Ridge National Laboratory(US) Spallation Neutron Source annotated.

    Brookhaven plays a role in a range of neutrino research projects around the world, including the Daya Bay Neutrino Experiment (CN) nuclear power plant, approximately 52 kilometers northeast of Hong Kong and 45 kilometers east of Shenzhen, China.

    Daya Bay Neutrino Experiment (CN) nuclear power plant, approximately 52 kilometers northeast of Hong Kong and 45 kilometers east of Shenzhen, China .

    FNAL DUNE LBNF (US) from FNAL to Sanford Underground Research Facility, Lead, South Dakota, USA.

    BNL Center for Functional Nanomaterials.

    BNL National Synchrotron Light Source II(US).

    BNL NSLS II (US).

    BNL Relative Heavy Ion Collider (US) Campus.

    BNL/RHIC Star Detector.

    BNL/RHIC Phenix detector.

     
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