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  • richardmitnick 12:38 pm on March 22, 2017 Permalink | Reply
    Tags: Accelerator Science, , NOvA sees first antineutrino,   

    From FNAL: “NOvA sees first antineutrino” 

    FNAL II photo

    FNAL Art Image
    FNAL Art Image by Angela Gonzales

    Fermilab is an enduring source of strength for the US contribution to scientific research world wide.

    March 21, 2017


    NOvA

    On Feb. 20, the NOvA neutrino experiment observed its first antineutrino, only two hours after the Fermilab accelerator complex switched to antineutrino delivery mode. The NOvA collaboration saw the antineutrino in the experiment’s far detector, which is located in northern Minnesota.

    NOvA scientists hope to learn more about how and why neutrinos change between one type and another. The three types, called flavors, are the muon, electron and tau neutrino. Over longer distances, neutrinos can flip between these flavors. NOvA is specifically designed to study muon neutrinos changing into electron neutrinos. Unraveling this mystery may help scientists understand why the universe is composed of matter and why that matter was not annihilated by antimatter after the Big Bang.

    1
    This plot shows the tracks of particles resulting from an antineutrino interaction inside the NOvA far detector. Image: NOvA collaboration

    See the full article here .

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    Fermilab Campus

    Fermi National Accelerator Laboratory (Fermilab), located just outside Batavia, Illinois, near Chicago, is a US Department of Energy national laboratory specializing in high-energy particle physics. Fermilab is America’s premier laboratory for particle physics and accelerator research, funded by the U.S. Department of Energy. Thousands of scientists from universities and laboratories around the world
    collaborate at Fermilab on experiments at the frontiers of discovery.

     
  • richardmitnick 11:59 am on March 22, 2017 Permalink | Reply
    Tags: Accelerator Science, , , , , Quest for the lost arc   

    From ATLAS: “Quest for the lost arc” 

    CERN ATLAS Higgs Event

    CERN/ATLAS
    ATLAS

    21st March 2017
    ATLAS Collaboration

    1
    Figure 1: ATLAS simulation showing a hypothetical new charged particle (χ1+) traversing the four layers of the pixel system and decaying to an invisible neutral particle (χ10) and an un-detected pion (π+). The red squares represent the particle interactions with the detector. (Image: ATLAS Collaboration/CERN)

    Nature has surprised physicists many times in history and certainly will do so again. Therefore, physicists have to keep an open mind when searching for phenomena beyond the Standard Model.

    ..
    The Standard Model of elementary particles (more schematic depiction), with the three generations of matter, gauge bosons in the fourth column, and the Higgs boson in the fifth.

    Some theories predict the existence of new particles that live for a very short time. These particles would decay to known particles that interact with the sophisticated “eyes” of the ATLAS detector. However, this may not be the case. An increasingly popular alternative is that some of these new particles may have masses very close to each other, and would thus travel some distance before decaying. This allows for the intriguing possibility of directly observing a new type of particle with the ATLAS experiment, rather than reconstructing it via its decay products as physicists do for example for the Higgs boson.

    2
    Figure 2: The number of reconstructed short tracks (tracklets) as a function of their transverse momentum (pT). ATLAS data (black points) are compared with the expected contribution from background sources (gray solid line shows the total) . A new particle would appear as an additional contribution at large pT, as shown for example by the dashed red line. The bottom panel shows the ratio of the data and the background predictions. The error band shows the uncertainty of the background expectation including both statistical and systematic uncertainties. (Image: ATLAS Collaboration/CERN)

    An attractive scenario predicts the existence of a new electrically charged particle, a chargino (χ1±), that may live long enough to travel a few tens of centimetres before decaying to an invisible neutral weakly interacting particle, a neutralino (χ10). A charged pion would also be produced in the decay but, due to the very similar mass of the chargino and the neutralino, its energy would not be enough for it to be detected. As shown in Figure 1, simulations predict a quite spectacular signature of a charged particle “disappearing” due to the undetected decay products.

    ATLAS physicists have developed dedicated algorithms to directly observe charged particles travelling as little as 12 centimetres from their origin. Thanks to the new Insertable B-Layer, these algorithms show improved performance reconstructing such charged particles that do not live long enough to interact with other ATLAS detector systems. So far, the abundance and properties of the observed particles are in agreement with what is expected from known background processes.

    New results presented at the Moriond Electroweak conference set very stringent limits on what mass such particles may have, if they exist. These limits severely constrain one important type of Supersymmetry dark matter. Although no new particle has been observed, ATLAS physicists continue the search for this “lost arc”. Stay tuned!

    See the full article here .

    CERN LHC Map
    CERN LHC Grand Tunnel
    CERN LHC particles
    LHC at CERN

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  • richardmitnick 1:08 pm on March 21, 2017 Permalink | Reply
    Tags: 30 million collision events, Accelerator Science, , , ,   

    From ATLAS: “Particle-hunting at the energy frontier” 

    CERN ATLAS Higgs Event

    CERN/ATLAS
    ATLAS

    20th March 2017
    ATLAS Collaboration

    1
    Fig. 1: The highest-mass dijet event measured by ATLAS (mass = 8.12TeV). Green lines indicate tracks of charged particles. Green and yellow blocks show the energy of the two back-to-back jets deposited in the calorimeters. (Image: ATLAS Collaboration/CERN)

    There are many mysteries the Standard Model of particle physics cannot answer. Why is there an imbalance between matter and anti-matter in our Universe? What is the nature of dark matter or dark energy? And many more. The existence of physics beyond the Standard Model can solve some of these fundamental questions. By studying the head-on collisions of protons at a centre-of-mass energy of 13 TeV provided by the LHC, the ATLAS Collaboration is on the hunt for signs of new physics.

    2
    Fig. 2: Dijet resonance search results. (Image: ATLAS Collaboration/CERN)

    A newly released ATLAS search studies approximately 30 million collision events that produce two high-energy sprays of particles in the final state. These sprays are known as “jets” or, when seen in pairs as in this case, “dijets” (Figure 1). Jets with extraordinarily high energies – copiously produced due to the strong interactions of quarks and gluons – probe the highest energy scales of all processes at the LHC. These jets can provide a window into new physics phenomena, and allow ATLAS physicists to search for mediators between Standard Model and dark matter particles or other hypothetical objects such as non-elementary quarks, heavy “partners” of known Standard Model particles or miniature quantum black-holes (a phenomenon of strong gravity predicted in models with additional spatial dimensions). They can even be used to search for very heavy particles with masses beyond the LHC collision energies, through models known as contact interactions (similar to the Fermi model for weak interactions).

    The dijet search described here consists of two complementary analyses: the resonance analysis and the angular analysis. The resonance analysis looks for a localized excess in the dijet mass spectrum. In the absence of a heavy resonance, the mass distribution is well described by a smooth, monotonically falling function. A statistically significant bump would signify a new particle with mass near the measured bump. The histogram in Figure 2 displays the results of the resonance analysis. The x-axis represents the dijet mass (mjj) and the y-axis (shown with a logarithmic scale) represents the number of observed events. The solid black dots show the data, the red curve represents the fit of a smooth function to the data, and the open green dots show how two non-elementary (“excited”) quark signals might look like. The second panel shows how significant the deviations in the data are as compared to the smooth background fit. The vertical blue lines show the region with the largest significance. A statistical analysis results in a probablility value of 0.63 which means that there is no significant deviation from the Standard Model. The third panel compares the data to the dijet mass prediction; again, no significant deviation from the Standard Model expectation is seen.

    See the full article here .

    CERN LHC Map
    CERN LHC Grand Tunnel
    CERN LHC particles
    LHC at CERN

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  • richardmitnick 1:22 pm on March 17, 2017 Permalink | Reply
    Tags: Accelerator Science, , , , , The LHC Just Discovered A New System of Five Particles   

    From Futurism: “The LHC Just Discovered A New System of Five Particles” 

    futurism-bloc

    Futurism

    3.17.17
    Sarah Marquart

    The Large Hadron Collider (LHC), the latest addition to CERN’s accelerator complex, is the most powerful particle accelerator ever built. It features a 27 kilometer (16 mile) ring made of superconducting magnets and accelerating structures built to boost the energy of particles in the chamber. In the accelerator, two high-energy particle beams are forced to collide from opposite directions at speeds close to the speed of light.




    LHC at CERN

    The energy densities that are created when these collisions occur cause ordinary matter to melt into its constituent parts—quarks and gluons. This allows us to interrogate the basic constituents of matter–the fundamental particles of the Standard Model.


    The Standard Model of elementary particles (more schematic depiction), with the three generations of matter, gauge bosons in the fourth column, and the Higgs boson in the fifth.

    It is a project of massive, unparalleled proportions.

    More than 10,000 scientists and engineers are currently working together to help us learn about the fundamental properties of physics using the LHC. To date, these men and women have brought about some impressive discoveries. The LHC team is responsible for the discovery of the Higgs Boson, potentially disproving the existence of the paranormal, and discovering a host of new particles.


    CERN CMS Higgs Event


    CERN/CMS Detector


    CERN ATLAS Higgs Event


    CERN/ATLAS detector

    And today, a paper proved that these discoveries aren’t slowing down.

    The Large Hadron Collider beauty experiment (LHCb) collaboration just announced the discovery of a new system of five particles all in a single analysis. Discovering a new state is a feat in itself – but discovering five new states all at once is exceptional. Especially since there’s such an overwhelming level of statistical significance – i.e. this isn’t just a fluke.


    CERN/LHCb

    3
    4
    Subsequently the Ξc+ candidates were combined with K- mesons present in the same event. The Ξc+ K- invariant mass distribution obtained in this way is shown in the right image above, revealing for the first time five narrow structures with an overwhelming statistical significance. These structures are interpreted as manifestations of excited states of the Ωc0 baryon. These excited states decay into a Ξc+ baryon and a K- meson via the strong interactions, in contrast to the weak decays responsible for the three particles used to form the Ξc+ mass peak.

    Excitement Abounds

    Each of the five particles were found to be excited states of Omega-c-zero, a particle with three quarks. These particle states are named, according to the standard convention, Ωc(3000)0, Ωc(3050)0, Ωc(3066)0, Ωc(3090)0 and Ωc(3119)0

    Now, the researchers need to determine the quantum numbers of these new particles, and their theoretical significance. This will all add to our understanding of the correlation between quarks, and multi-quark states, which will further the way we comprehend our universe and quantum theory in general.

    Ultimately, CERN called this “a hotbed of new and outstanding physics results.” And it’s just the beginning. More experiments and results are on their way.


    Access mp4 video here .

    This is why the importance of international collaborations cannot be overstated. The LHC is the largest international scientific collaboration in history (scientists from more than 85 countries are involved in the LHC and its experiments at the European laboratory CERN). As such, perhaps it is no surprise that it is leading to a new era in physics and opening new doors in our understanding of the universe, in fact, it could even prove the existence of higher dimensions.

    Over the coming months and years, the LHC will use its amazing amount of energy to open up the “dark sector of physics,” revealing currently unknown particles and helping solve some of our greatest cosmic mysteries (such as dark matter, parallel dimensions, and what happened during the earliest moments of the Big Bang). With new updates coming to the LHC, the team promises “even more impressive” physics opportunities.

    See the full article here .

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    Futurism covers the breakthrough technologies and scientific discoveries that will shape humanity’s future. Our mission is to empower our readers and drive the development of these transformative technologies towards maximizing human potential.

     
  • richardmitnick 11:22 am on March 16, 2017 Permalink | Reply
    Tags: Accelerator Science, , , , , , Science and Technology Facilities Council (STFC)   

    From CERN via Accelerating News: “HL-LHC project stimulates new collaboration” 

    Cern New Bloc

    Cern New Particle Event

    CERN New Masthead

    CERN

    Accelerating News

    1
    View from the LHC tunnel (Credit: CERN)

    A new multi-million-pound project between CERN, the Science and Technology Facilities Council (STFC) and six other UK institutions has been launched to contribute to the upgrade of the Large Hadron Collider (LHC) at CERN in Geneva. The world’s highest energy particle collider shall be upgraded to the High Luminosity LHC (HL-LHC) in the 2020s through international collaboration.

    The challenges of this project are best tackled with input from the project partners from around the world. Several partnerships have already been established with the HL-LHC project and there is room for more potential partnerships in the future. It has now been announced that the UK will make contributions in four areas across the new HL-LHC-UK project among other contributions from UK universities.

    The full exploitation of the LHC is the highest priority in the European Strategy for Particle Physics, adopted by the CERN Council and integrated into the ESFRI Roadmap. The full HL-LHC project funding was approved by the CERN Council in June 2016. To extend its discovery potential, the LHC will need a major upgrade around 2025 to increase its luminosity (rate of collisions) by a factor of 10 beyond the original design value (from 300 to 3,000 fb-1). This will enable scientists to look for new, very rare fundamental particles, and to measure known particles such as the Higgs boson with unprecedented accuracy.

    Upgrading the LHC calls for technology breakthroughs in areas already under study, and requires about 10 years of research to implement. HL-LHC relies on a number of key innovative technologies, representing exceptional technological challenges. Led by experts from the Cockcroft Institute, the HL-LHC-UK project has now been established to address these challenges.

    Within HL-LHC-UK, the partner institutions will perform cutting-edge research and deliver hardware for the LHC upgrade in four areas: 1) proton beam collimation to remove stray halo protons, 2) the development and test of transverse deflecting cavities (“crab cavities”), 3) new methods to diagnose the stored beams including gas jet-based beam profile monitors and, 4) novel beam position monitors, as well as sophisticated cold powering technology needed for the cryogenic systems.

    Lucio Rossi, Head of the High-Luminosity LHC project, commented: “In order to make the project a success we have to innovate in many fields, developing cutting-edge technologies for magnets, the optics of the accelerator, superconducting radiofrequency cavities, and superconducting links. We are very excited for the UK to be making key contributions and using their expertise to help deliver this upgrade.”

    The HL-LHC-UK project comprises the University of Manchester (Cockcroft Institute), Lancaster University (Cockcroft Institute), the University of Liverpool (Cockcroft Institute), the University of Huddersfield (International Institute of Accelerator Applications), Royal Holloway University of London (John Adams Institute), the University of Southampton and the Science and Technology Facilities Council (STFC). The spokesperson is Rob Appleby (Manchester) and the project manager is Graeme Burt (Lancaster).

    More information about the High Luminosity LHC project, its technology and design as well as the challenges ahead can be found in the recently released open access HiLumi LHC book The High Luminosity Large Hadron Collider. The New Machine for Illuminating the Mysteries of the Universe.

    See the full article here.

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    Meet CERN in a variety of places:

    Quantum Diaries
    QuantumDiaries

    Cern Courier

    CernCourier
    THE FOUR MAJOR PROJECT COLLABORATIONS

    ATLAS
    CERN ATLAS New

    ALICE
    CERN ALICE New

    CMS
    CERN CMS New

    LHCb
    CERN LHCb New II

    LHC

    CERN LHC Map
    CERN LHC Grand Tunnel

    CERN LHC particles

    Quantum Diaries

     
  • richardmitnick 10:47 am on March 16, 2017 Permalink | Reply
    Tags: Accelerator Science, , , , , ,   

    From CERN via Accelerating News: “CESSAMag delivering impact” 

    Cern New Bloc

    Cern New Particle Event

    CERN New Masthead

    CERN

    Accelerating News

    3.16.17
    Livia Lapadatescu (CERN)

    1
    Section of the SESAME Main Accelerator Ring (Image credit: CERN)

    The main objective of the FP7-CESSAMag (CERN-EC Support for SESAME Magnets) project was to support the construction of the SESAME light source in the Middle-East. With financial contribution from the EC, CERN’s main objective was to deliver the magnetic system and its powering scheme for the SESAME main accelerator ring, as well as to support the training of SESAME staff. Completed at the end of 2016, the project fulfilled or exceeded all its objectives.

    Scientific and technical impact of CESSAMag

    Building upon SESAME studies, CESSAMag finalized the requirements and design and produced the engineering and technical drawings of the SESAME magnets and powering scheme. The first main result of CESSAMag is the production of design reports on the combined function bending magnets, on the quadrupole magnets (long and short), on the sextupole magnets with their auxiliary corrector windings and on the powering scheme. These design and engineering study reports were used as background for the technical specifications needed for tendering and can serve as reference for the construction of similar light sources.

    During the tendering process, CERN made a special effort to place orders not only with experienced European companies, but also with companies based in some of the SESAME Members (Cyprus, Israel, Pakistan, Turkey), without former experience in accelerator components (except for Israel), but demonstrating potential and motivation. This was achieved through effective knowledge transfer from CERN and generated potential commercial impact in the companies trained.

    All magnets successfully passed the acceptance tests at either ALBA-CELLS or CERN and their measured field quality and reproducibility from magnet to magnet are excellent, making them a reference for similar synchrotrons. Therefore, a key result of CESSAMag is the string of magnets forming the SESAME storage ring, composed of:

    16 combined function bending magnets (dipole + quadrupole)

    64 quadrupoles of two types: 32 long focusing and 32 short defocusing quadrupoles

    64 sextupole/correctors

    CESSAMag also contributed to the production of an improved magnet powering scheme: rather than procuring power supplies adapted to each kind of magnet, another approach was proposed by CERN, based on light source standards (PSI), which allows individual powering of quadrupoles and simplified maintenance by plug-and-play modules by standardizing interfaces. With this strategy, SESAME benefits from a powering strategy more powerful, flexible and robust than initially foreseen.

    Following the decision to procure some components from companies based in the SESAME Members and thanks to the in-kind contribution of Pakistan, offering the assembly of 50% of the sextupoles, CESSAMag managed to deliver a more powerful and complete magnetic system and reduce the financial share that SESAME was due to contribute to the project.

    Finally, CESSAMag contributed to the magnet integration and commissioning, with the goal of making SESAME fully in control of the equipment delivered by CERN.

    The first beam was circulated in the SESAME main accelerator ring on 11 January 2017 and it was stored and accumulated up to 20mA in mid-February. The next step is ramping the beam and completing the RF stations and final acceleration assessment expected before the end of summer. The inauguration ceremony of the SESAME light source will take place in mid-May with the foreseen presence of high-ranking officials from SESAME Members and Observers. The first user experiments are foreseen to start in Q3.

    Political and social impact of CESSAMag

    A significant aspect showcasing the socio-economic impact of CESSAMag is the knowledge transfer to companies from SESAME Members and training of SESAME staff. The duration of training to staff, engineers and companies from SESAME Members amounts to about 90 person-months and the CERN personnel effort in training and knowledge transfer amounts to 16 person-months.

    In the context of CESSAMag, international collaborations and agreements were established between CERN and SESAME and CERN and ALBA-CELLS; implementation agreements were formed with PAEK (Pakistan), TAEK (Turkey) and ILSF (Iran) and an informal collaboration with IAEA, which provided financial support for training and experts’ visits between CERN and SESAME. These collaborations and agreements illustrate the international and science diplomacy dimensions of the project.

    Furthermore, the European Union acknowledged the science diplomacy impact of CESSAMag and made further steps in support of SESAME. Since 2015, the EU is an Observer in the SESAME Council and the EC decided to further support the training of SESAME users and staff in the framework of the OPEN SESAME (Opening Synchrotron Light for Experimental Science and Applications in the Middle East) H2020 “Policy and international cooperation measures for research infrastructures” project.

    See the full article here.

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    Meet CERN in a variety of places:

    Quantum Diaries
    QuantumDiaries

    Cern Courier

    CernCourier
    THE FOUR MAJOR PROJECT COLLABORATIONS

    ATLAS
    CERN ATLAS New

    ALICE
    CERN ALICE New

    CMS
    CERN CMS New

    LHCb
    CERN LHCb New II

    LHC

    CERN LHC Map
    CERN LHC Grand Tunnel

    CERN LHC particles

    Quantum Diaries

     
  • richardmitnick 2:03 pm on March 14, 2017 Permalink | Reply
    Tags: Accelerator Science, , ,   

    From Symmetry: “The life of an accelerator” 

    Symmetry Mag

    Symmetry

    03/14/17
    Manuel Gnida


    SLAC

    Tens of thousands of accelerators exist around the world, producing powerful particle beams for the benefit of medical diagnostics, cancer therapy, industrial manufacturing, material analysis, national security, and nuclear as well as fundamental particle physics. Particle beams can also be used to produce powerful beams of X-rays.

    Many of these particle accelerators rely on artfully crafted components called cavities.

    The world’s longest linear accelerator (also known as a linac) sits at the Department of Energy’s SLAC National Accelerator Laboratory. It stretches two miles and accelerates bunches of electrons to very high energies.

    The SLAC linac has undergone changes in its 50 years of operation that illustrate the evolution of the science of accelerator cavities. That evolution continues and will determine what the linac does next.


    SLAC/LCLS II

    Robust copper

    An accelerator cavity is a mostly closed, hollow chamber with an opening on each side for particles to pass through. As a particle moves through the cavity, it picks up energy from an electromagnetic field stored inside. Many cavities can be lined up like beads on a string to generate higher and higher particle energies.

    When SLAC’s linac first started operations, each of its cavities was made exclusively from copper. Each tube-like cavity consisted of a 1-inch-long, 4-inch-wide cylinder with disks on either side. Technicians brazed together more than 80,000 cavities to form a straight particle racetrack.

    Scientists generate radiofrequency waves in an apparatus called a klystron that distributes them to the cavities. Each SLAC klystron serves a 10-foot section of the beam line. The arrival of the electron bunch inside the cavity is timed to match the peak in the accelerating electric field. When a particle arrives inside the cavity at the same time as the peak in the electric field, then that bunch is optimally accelerated.

    “Particles only gain energy if the variable electric field precisely matches the particle motion along the length of the accelerator,” says Sami Tantawi, an accelerator physicist at Stanford University and SLAC. “The copper must be very clean and the shape and size of each cavity must be machined very carefully for this to happen.”

    In its original form, SLAC’s linac boosted electrons and their antimatter siblings, positrons, to an energy of 50 billion electronvolts. Researchers used these beams of accelerated particles to study the inner structure of the proton, which led to the discovery of fundamental particles known as quarks.

    Today almost all accelerators in the world—including smaller systems for medical and industrial applications—are made of copper. Copper is a good electric conductor, which is important because the radiofrequency waves build up an accelerating field by creating electric currents in the cavity walls. Copper can be machined very smoothly and is cheaper than other options, such as silver.

    “Copper accelerators are very robust systems that produce high acceleration gradients of tens of millions of electronvolts per meter, which makes them very attractive for many applications,” says SLAC accelerator scientist Chris Adolphsen.

    Today, one-third of SLAC’s original copper linac is used to accelerate electrons for the Linac Coherent Light Source, a facility that turns energy from the electron beam into what is currently the world’s brightest X-ray laser light.

    Researchers continue to push the technology to higher and higher gradients—that is, larger and larger amounts of acceleration over a given distance.

    “Using sophisticated computer programs on powerful supercomputers, we were able to develop new cavity geometries that support almost 10 times larger gradients,” Tantawi says. “Mixing small amounts of silver into the copper further pushes the technology toward its natural limits.” Cooling the copper to very low temperatures helps as well. Tests at 45 Kelvin—negative 384 degrees Fahrenheit—have shown to increase acceleration gradients 20-fold compared to SLAC’s old linac.

    Copper accelerators have their limitations, though. SLAC’s historic linac produces 120 bunches of particles per second, and recent developments have led to copper structures capable of firing 80 times faster. But for applications that need much higher rates, Adolphsen says, “copper cavities don’t work because they would melt.”

    Chill niobium

    For this reason, crews at SLAC are in the process of replacing one-third of the original copper linac with cavities made of niobium.

    Niobium can support very large bunch rates, as long as it is cooled. At very low temperatures, it is what’s known as a superconductor.

    “Below the critical temperature of 9.2 Kelvin, the cavity walls conduct electricity without losses, and electromagnetic waves can travel up and down the cavity many, many times, like a pendulum that goes on swinging for a very long time,” says Anna Grassellino, an accelerator scientist at Fermi National Accelerator Laboratory. “That’s why niobium cavities can store electromagnetic energy very efficiently and can operate continuously.”

    You can find superconducting niobium cavities in modern particle accelerators such as the Large Hadron Collider at CERN and the CEBAF accelerator at Thomas Jefferson National Accelerator Facility. The European X-ray Free-Electron Laser in Germany, the European Spallation Source at CERN, and the Facility for Rare Isotope Beams at Michigan State University are all being built using niobium technology. Niobium cavities also appear in designs for the next-generation International Linear Collider.

    At SLAC, the niobium cavities will support LCLS-II, an X-ray laser that will produce up to a million ultrabright light flashes per second. The accelerator will have 280 cavities, each about three feet long with a 3-inch opening for the electron beam to fly through. Sets of eight cavities will be strung together into cryomodules that keep the cavities at a chilly 2 Kelvin, which is colder than interstellar space.

    Each niobium cavity is made by fusing together two halves stamped from a sheet of pure metal. The cavities are then cleaned very thoroughly because even the tiniest impurities would degrade their performance.

    The shape of the cavities is reminiscent of a stack of shiny donuts. This is to maximize the cavity volume for energy storage and to minimize its surface area to cut down on energy dissipation. The exact size and shape also depends on the type of accelerated particle.

    “We’ve come a long way since the first development of superconducting cavities decades ago,” Grassellino says. “Today’s niobium cavities produce acceleration gradients of up to about 50 million electronvolts per meter, and R&D work at Fermilab and elsewhere is further pushing the limits.”

    Hot plasma

    Over the past few years, SLAC accelerator scientists have been working on a way to push the limits of particle acceleration even further: accelerating particles using bubbles of ionized gas called plasma.

    Plasma wakefield acceleration is capable of creating acceleration gradients that are up to 1000 times larger than those of copper and niobium cavities, promising to drastically shrink the size of particle accelerators and make them much more powerful.

    “These plasma bubbles have certain properties that are very similar to conventional metal cavities,” says SLAC accelerator physicist Mark Hogan. “But because they don’t have a solid surface, they can support extremely high acceleration gradients without breaking down.”

    Hogan’s team at SLAC and collaborators from the University of California, Los Angeles, have been developing their plasma acceleration method at the Facility for Advanced Accelerator Experimental Tests, using an oven of hot lithium gas for the plasma and an electron beam from SLAC’s copper linac.

    Researchers create bubbles by sending either intense laser light or a high-energy beam of charged particles through plasma. They then send beams of particles through the bubbles to be accelerated.

    When, for example, an electron bunch enters a plasma, its negative charge expels plasma electrons from its flight path, creating a football-shaped cavity filled with positively charged lithium ions. The expelled electrons form a negatively charged sheath around the cavity.

    This plasma bubble, which is only a few hundred microns in size, travels at nearly the speed of light and is very short-lived. On the inside, it has an extremely strong electric field. A second electron bunch enters that field and experiences a tremendous energy gain. Recent data show possible energy boosts of billions of electronvolts in a plasma column of just a little over a meter.

    “In addition to much higher acceleration gradients, the plasma technique has another advantage,” says UCLA researcher Chris Clayton. “Copper and niobium cavities don’t keep particle beams tightly bundled and require the use of focusing magnets along the accelerator. Plasma cavities, on the other hand, also focus the beam.”

    Much more R&D work is needed before plasma wakefield accelerator technology can be turned into real applications. But it could represent the future of particle acceleration at SLAC and of accelerator science as a whole.

    See the full article here .

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    Symmetry is a joint Fermilab/SLAC publication.


     
  • richardmitnick 11:02 am on March 14, 2017 Permalink | Reply
    Tags: Accelerator Science, , , , Vector boson plus jet event   

    From ALCF: “High-precision calculations help reveal the physics of the universe” 

    Argonne Lab
    News from Argonne National Laboratory

    ANL Cray Aurora supercomputer
    Cray Aurora supercomputer at the Argonne Leadership Computing Facility

    MIRA IBM Blue Gene Q supercomputer at the Argonne Leadership Computing Facility
    MIRA IBM Blue Gene Q supercomputer at the Argonne Leadership Computing Facility

    ALCF

    March 9, 2017
    Joan Koka

    1
    With the theoretical framework developed at Argonne, researchers can more precisely predict particle interactions such as this simulation of a vector boson plus jet event. Credit: Taylor Childers, Argonne National Laboratory

    On their quest to uncover what the universe is made of, researchers at the U.S. Department of Energy’s (DOE) Argonne National Laboratory are harnessing the power of supercomputers to make predictions about particle interactions that are more precise than ever before.

    Argonne researchers have developed a new theoretical approach, ideally suited for high-performance computing systems, that is capable of making predictive calculations about particle interactions that conform almost exactly to experimental data. This new approach could give scientists a valuable tool for describing new physics and particles beyond those currently identified.

    The framework makes predictions based on the Standard Model, the theory that describes the physics of the universe to the best of our knowledge. Researchers are now able to compare experimental data with predictions generated through this framework, to potentially uncover discrepancies that could indicate the existence of new physics beyond the Standard Model. Such a discovery would revolutionize our understanding of nature at the smallest measurable length scales.

    “So far, the Standard Model of particle physics has been very successful in describing the particle interactions we have seen experimentally, but we know that there are things that this model doesn’t describe completely.


    The Standard Model of elementary particles (more schematic depiction), with the three generations of matter, gauge bosons in the fourth column, and the Higgs boson in the fifth.

    We don’t know the full theory,” said Argonne theorist Radja Boughezal, who developed the framework with her team.

    “The first step in discovering the full theory and new models involves looking for deviations with respect to the physics we know right now. Our hope is that there is deviation, because it would mean that there is something that we don’t understand out there,” she said.

    The theoretical method developed by the Argonne team is currently being deployed on Mira, one of the fastest supercomputers in the world, which is housed at the Argonne Leadership Computing Facility, a DOE Office of Science User Facility.

    Using Mira, researchers are applying the new framework to analyze the production of missing energy in association with a jet, a particle interaction of particular interest to researchers at the Large Hadron Collider (LHC) in Switzerland.




    LHC at CERN

    Physicists at the LHC are attempting to produce new particles that are known to exist in the universe but have yet to be seen in the laboratory, such as the dark matter that comprises a quarter of the mass and energy of the universe.


    Dark matter cosmic web and the large-scale structure it forms The Millenium Simulation, V. Springel et al

    Although scientists have no way today of observing dark matter directly — hence its name — they believe that dark matter could leave a “missing energy footprint” in the wake of a collision that could indicate the presence of new particles not included in the Standard Model. These particles would interact very weakly and therefore escape detection at the LHC. The presence of a “jet”, a spray of Standard Model particles arising from the break-up of the protons colliding at the LHC, would tag the presence of the otherwise invisible dark matter.

    In the LHC detectors, however, the production of a particular kind of interaction — called the Z-boson plus jet process — can mimic the same signature as the potential signal that would arise from as-yet-unknown dark matter particles. Boughezal and her colleagues are using their new framework to help LHC physicists distinguish between the Z-boson plus jet signature predicted in the Standard Model from other potential signals.

    Previous attempts using less precise calculations to distinguish the two processes had so much uncertainty that they were simply not useful for being able to draw the fine mathematical distinctions that could potentially identify a new dark matter signal.

    “It is only by calculating the Z-boson plus jet process very precisely that we can determine whether the signature is indeed what the Standard Model predicts, or whether the data indicates the presence of something new,” said Frank Petriello, another Argonne theorist who helped develop the framework. “This new framework opens the door to using Z-boson plus jet production as a tool to discover new particles beyond the Standard Model.”

    Applications for this method go well beyond studies of the Z-boson plus jet. The framework will impact not only research at the LHC, but also studies at future colliders which will have increasingly precise, high-quality data, Boughezal and Petriello said.

    “These experiments have gotten so precise, and experimentalists are now able to measure things so well, that it’s become necessary to have these types of high-precision tools in order to understand what’s going on in these collisions,” Boughezal said.

    “We’re also so lucky to have supercomputers like Mira because now is the moment when we need these powerful machines to achieve the level of precision we’re looking for; without them, this work would not be possible.”

    Funding and resources for this work was previously allocated through the Argonne Leadership Computing Facility’s (ALCF’s) Director’s Discretionary program; the ALCF is supported by the DOE’s Office of Science’s Advanced Scientific Computing Research program. Support for this work will continue through allocations coming from the Innovation and Novel Computational Impact on Theory and Experiment (INCITE) program.

    The INCITE program promotes transformational advances in science and technology through large allocations of time on state-of-the-art supercomputers.

    See the full article here .

    Please help promote STEM in your local schools.
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    Argonne National Laboratory seeks solutions to pressing national problems in science and technology. The nation’s first national laboratory, Argonne conducts leading-edge basic and applied scientific research in virtually every scientific discipline. Argonne researchers work closely with researchers from hundreds of companies, universities, and federal, state and municipal agencies to help them solve their specific problems, advance America’s scientific leadership and prepare the nation for a better future. With employees from more than 60 nations, Argonne is managed by UChicago Argonne, LLC for the U.S. Department of Energy’s Office of Science. For more visit http://www.anl.gov.

    About ALCF

    The Argonne Leadership Computing Facility’s (ALCF) mission is to accelerate major scientific discoveries and engineering breakthroughs for humanity by designing and providing world-leading computing facilities in partnership with the computational science community.

    We help researchers solve some of the world’s largest and most complex problems with our unique combination of supercomputing resources and expertise.

    ALCF projects cover many scientific disciplines, ranging from chemistry and biology to physics and materials science. Examples include modeling and simulation efforts to:

    Discover new materials for batteries
    Predict the impacts of global climate change
    Unravel the origins of the universe
    Develop renewable energy technologies

    Argonne is managed by UChicago Argonne, LLC for the U.S. Department of Energy’s Office of Science

    Argonne Lab Campus

     
  • richardmitnick 8:51 pm on March 10, 2017 Permalink | Reply
    Tags: Accelerator Science, , , , , , , , , The strong force (strong interaction)   

    From Symmetry: “A strength test for the strong force [strong interaction]” 

    Symmetry Mag

    Symmetry

    03/10/17
    Sarah Charley

    1
    Science Saturday

    New research could tell us about particle interactions in the early universe and even hint at new physics.

    Much of the matter in the universe is made up of tiny particles called quarks. Normally it’s impossible to see a quark on its own because they are always bound tightly together in groups. Quarks only separate in extreme conditions, such as immediately after the Big Bang or in the center of stars or during high-energy particle collisions generated in particle colliders.

    Scientists at Louisiana Tech University are working on a study of quarks and the force that binds them by analyzing data from the ATLAS experiment at the LHC. Their measurements could tell us more about the conditions of the early universe and could even hint at new, undiscovered principles of physics.


    ATLAS at the LHC

    The particles that stick quarks together are aptly named “gluons.” Gluons carry the strong force, one of four fundamental forces in the universe that govern how particles interact and behave. The strong force binds quarks into particles such as protons, neutrons and atomic nuclei.

    As its name suggests, the strong force [strong interaction] is the strongest—it’s 100 times stronger than the electromagnetic force (which binds electrons into atoms), 10,000 times stronger than the weak force (which governs radioactive decay), and a hundred million million million million million million (1039) times stronger than gravity (which attracts you to the Earth and the Earth to the sun).

    But this ratio shifts when the particles are pumped full of energy. Just as real glue loses its stickiness when overheated, the strong force carried by gluons becomes weaker at higher energies.

    “Particles play by an evolving set of rules,” says Markus Wobisch from Louisiana Tech University. “The strength of the forces and their influence within the subatomic world changes as the particles’ energies increase. This is a fundamental parameter in our understanding of matter, yet has not been fully investigated by scientists at high energies.”

    Characterizing the cohesiveness of the strong force is one of the key ingredients to understanding the formation of particles after the Big Bang and could even provide hints of new physics, such as hidden extra dimensions.

    “Extra dimensions could help explain why the fundamental forces vary dramatically in strength,” says Lee Sawyer, a professor at Louisiana Tech University. “For instance, some of the fundamental forces could only appear weak because they live in hidden extra dimensions and we can’t measure their full strength. If the strong force is weaker or stronger than expected at high energies, this tells us that there’s something missing from our basic model of the universe.”

    By studying the high-energy collisions produced by the LHC, the research team at Louisiana Tech University is characterizing how the strong force pulls energetic quarks into encumbered particles. The challenge they face is that quarks are rambunctious and caper around inside the particle detectors. This subatomic soirée involves hundreds of particles, often arising from about 20 proton-proton collisions happening simultaneously. It leaves a messy signal, which scientists must then reconstruct and categorize.

    Wobisch and his colleagues innovated a new method to study these rowdy groups of quarks called jets. By measuring the angles and orientations of the jets, he and his colleagues are learning important new information about what transpired during the collisions—more than what they can deduce by simple counting the jets.

    The average number of jets produced by proton-proton collisions directly corresponds to the strength of the strong force in the LHC’s energetic environment.

    “If the strong force is stronger than predicted, then we should see an increase in the number of proton-protons collisions that generate three jets. But if the strong force is actually weaker than predicted, then we’d expect to see relatively more collisions that produce only two jets. The ratio between these two possible outcomes is the key to understanding the strong force.”

    After turning on the LHC, scientists doubled their energy reach and have now determined the strength of the strong force up to 1.5 trillion electronvolts, which is roughly the average energy of every particle in the universe just after the Big Bang. Wobisch and his team are hoping to double this number again with more data.

    “So far, all our measurements confirm our predictions,” Wobisch says. “More data will help us look at the strong force at even higher energies, giving us a glimpse as to how the first particles formed and the microscopic structure of space-time.”

    See the full article here .

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    Symmetry is a joint Fermilab/SLAC publication.


     
  • richardmitnick 10:04 am on March 10, 2017 Permalink | Reply
    Tags: Accelerator Science, , , , , , , , , , Xiaofeng Guo   

    From Brookhaven: Women in STEM – “Secrets to Scientific Success: Planning and Coordination” Xiaofeng Guo 

    Brookhaven Lab

    March 8, 2017
    Lida Tunesi

    1
    Xiaofeng Guo

    Very often there are people behind the scenes of scientific advances, quietly organizing the project’s logistics. New facilities and big collaborations require people to create schedules, manage resources, and communicate among teams. The U.S. Department of Energy’s Brookhaven National Laboratory is lucky to have Xiaofeng Guo in its ranks—a skilled project manager who coordinates projects reaching across the U.S. and around the world.

    Guo, who has a Ph.D. in theoretical physics from Iowa State University, is currently deputy manager for the U.S. role in two upgrades to the ATLAS detector, one of two detectors at CERN’s Large Hadron Collider that found the Higgs boson in 2012.


    CERN ATLAS Higgs Event


    CERN/ATLAS detector

    Brookhaven is the host laboratory for both U.S. ATLAS Phase I and High Luminosity LHC (HL-LHC) upgrade projects, which involve hundreds of millions of dollars and 46 institutions across the nation. The upgrades are complex international endeavors that will allow the detector to make use of the LHC’s ramped up particle collision rates. Guo keeps both the capital and the teams on track.

    “I’m in charge of all business processes, project finance, contracts with institutions, baseline plan reports, progress reports—all aspects of business functions in the U.S. project team. It keeps me very busy,” she laughed. “In the beginning I was thinking ‘in my spare time I can still read physics papers, do my own calculations’… And now I have no spare time!”

    Guo’s dual interest in physics and management developed early in her career.

    “When I was an undergraduate there was a period when I actually signed up for a double major, with classes in finance and economics in addition to physics,” Guo recalled. “I’m happy to explore different things!”

    Later, while teaching physics part-time at Iowa State University, Guo desired career flexibility and studied to be a Chartered Financial Analyst. She passed all required exams in just two years but decided to continue her research after receiving a grant from the National Science Foundation.

    Guo joined Brookhaven Lab in 2010 to fill a need for project management in Nuclear and Particle Physics (NPP). The position offered her a way to learn new skills while staying up-to-date on the physics world.

    Early in her time at Brookhaven, Guo participated in the management of the Heavy Flavor Tracker (HFT) upgrade to the STAR particle detector at the Relativistic Heavy Ion Collider (RHIC), a DOE Office of Science User Facility for nuclear physics research. The project was successfully completed $600,000 under budget and a whole year ahead of schedule.


    BNL/RHIC Star Detector

    “This was a very good learning experience for me. I participated in all the manager meeting discussions, updated the review documents, and helped them handle some contracts. Through this process I learned all the DOE project rules,” Guo said.

    While working on the HFT upgrade, Guo also helped develop successful, large group proposals for increased computational resources in high-energy physics and other fields of science. She joined the ATLAS Upgrade projects after receiving her Project Management Certification, and her physics and finance background as well as experience with large collaborations have enabled her to orchestrate complex planning efforts.

    For the two phases of the U.S. ATLAS upgrade, Guo directly coordinates more than 140 scientists, engineers, and finance personnel, and oversees all business processes, including finance, contracts, and reports. And taking her job one step further, she’s developed entirely new management tools and reporting procedures to keep the multi-institutional effort synchronized.

    “Dr. Guo is one of our brightest stars,” said Berndt Mueller, Associate Lab Director of NPP. “We are fortunate to have her to assist us with many challenging aspects of project development and execution in NPP. In the process of guiding the work of scores of scientists and engineers, she has single-handedly created a unique and essential role in the development of complex projects with an international context, demonstrating skills of unusual depth and breadth and the ability to apply them across a wide array of disciplines.”

    Guo’s management of Phase I won great respect for the project from the high-energy physics community and the Office of Project Assessment (OPA) at the DOE’s Office of Science. The OPA invited her to participate in a panel discussion to share her expertise and help develop project management guidelines that can be used in other Office of Science projects. Guo also worked with BNL’s Project Management Center to help the lab update its own project management system description to meet DOE standards and lay down valuable groundwork for future large projects.

    As the ATLAS Phase I upgrade proceeds through the final construction stage, Guo is simultaneously managing the planning stages of HL-LHC.

    “We haven’t completely defined the project timeline yet, but it’s projected to go all the way to the end of 2025,” Guo said.

    Like Phase I, HL-LHC will ensure ATLAS can perform well while the LHC operates at much higher collision rates so that physicists can further explore the Higgs as well as search for signs of dark matter and extra dimensions.

    Although she admits to missing doing research herself, Guo is not disheartened.

    “I’m still in the physics world; I’m still working with physicists,” she said. “I enjoy working and interacting with people. So I’m happy.”

    Brookhaven’s work on RHIC and ATLAS is funded by the DOE Office of Science.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

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    BNL Campus

    One of ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy (DOE), 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, the largest academic user of Laboratory facilities, and Battelle, a nonprofit, applied science and technology organization.
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