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  • richardmitnick 8:03 am on August 21, 2015 Permalink | Reply
    Tags: , , , DESY   

    From DESY: “The Standard Model prevails – so far” 

    DESY
    DESY

    2015/08/20
    No Writer Credit

    1
    A top quark candidate in the CMS detector. Credit: CMS Collaboration

    2
    Top quark pair production cross section measurements compared to the Standard Model predictions as a function of the center-of-mass energy. The new result of the CMS collaboration at 13 TeV is displayed in red and is in agreement with the theory prediction (green band). Credit: CMS Collaboration

    CMS experiment publishes first test at new LHC energy of 13 TeV

    Shortly after the start of Run 2 at the in June 2015, scientists from DESY and their colleagues from the experiments CMS and ATLAS have performed a first important test of the Standard Model of particle physics at the new energy frontier, using data from proton-proton collisions at higher proton beam energies than ever achieved before. They looked at the production rate of a well-known particle called the top quark to see if it behaves differently at higher collision energies. Their study shows: it doesn’t.

    4
    A collision event involving top quarks

    CERN CMS Detector
    CMS

    CERN ATLAS New
    ATLAS

    3
    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.

    Top quarks are the heaviest and among the most puzzling elementary particles. They weigh even more than the Higgs boson discovered in 2012 and might have a special connection to it. To analyse this relation and to test if the top quark is exactly the particle predicted by the current theory, physicists at the LHC perform high-precision measurements of the properties of the top quark.

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

    One of the most exciting studies to that respect is to measure the production rate, or cross section, for top quark pairs in the new energy range never explored before because it provides an excellent test of the Standard Model and might give scientists a first glimpse of new physics beyond.

    DESY scientists led the effort to measure the top quark pair production cross section at a proton-proton collision energy of 13 TeV. “The results are in good agreement with what we expected. This is a another huge success of the Standard Model,” said Alexander Grohsjean from DESY’s CMS group. The results are presented and discussed this week at the international high energy physics conference “XXVII International Symposium on Lepton Photon Interaction at High Energies”.

    See the full article here.

    Please help promote STEM in your local schools.

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    desi

    DESY is one of the world’s leading accelerator centres. Researchers use the large-scale facilities at DESY to explore the microcosm in all its variety – from the interactions of tiny elementary particles and the behaviour of new types of nanomaterials to biomolecular processes that are essential to life. The accelerators and detectors that DESY develops and builds are unique research tools. The facilities generate the world’s most intense X-ray light, accelerate particles to record energies and open completely new windows onto the universe. 
That makes DESY not only a magnet for more than 3000 guest researchers from over 40 countries every year, but also a coveted partner for national and international cooperations. Committed young researchers find an exciting interdisciplinary setting at DESY. The research centre offers specialized training for a large number of professions. DESY cooperates with industry and business to promote new technologies that will benefit society and encourage innovations. This also benefits the metropolitan regions of the two DESY locations, Hamburg and Zeuthen near Berlin.

     
  • richardmitnick 2:55 pm on July 24, 2015 Permalink | Reply
    Tags: , , DESY,   

    From SLAC: “SLAC and DESY Join Forces at Bilateral Strategy Meeting” 


    SLAC Lab

    July 24, 2015

    The German research center DESY and SLAC will work closer together in the future: That was the outcome of a meeting of senior managers of both labs who convened July 16-17 at SLAC to discuss a joint strategy for more collaboration.

    On the first day, SLAC and DESY representatives talked about their labs’ current research activities and future plans, exposing a variety of commonalities and also differences between the research centers. This led to discussions on the second day that identified areas where the labs can best collaborate with each other.

    The meeting’s attendees found plenty of common ground. They compiled a comprehensive list of common interests, including advancements in X-ray laser technology, particle physics detectors, future compact accelerators and computing methods to handle ever-increasing amounts of scientific data produced in X-ray, particle physics and cosmology experiments.

    “SLAC and DESY have so many things in common, and we already work on many projects together,” said SLAC Director Chi-Chang Kao. “Meetings like this help us identify how we can work on the most challenging problems even closer and better together.”

    Helmut Dosch, the chairman of DESY’s board of directors, added, “The meeting was a wonderful opportunity to openly discuss the potential that the two world-class research centers have together.”

    1
    The first DESY-SLAC strategy meeting at SLAC, July 16-17, 2015. Left to right: Michael Fazio, SLAC ALD, Technology Innovation Directorate; Mike Dunne, SLAC ALD, LCLS; Vitaly Yakimenko, SLAC division director, FACET; Joachim Mnich, DESY Particle Physics and Astroparticle Physics director; Norbert Holtkamp, SLAC deputy director; Helmut Dosch, chairman of the DESY board of directors; Kelly Gaffney, SLAC ALD, SSRL; Mike Willardson, SLAC tech transfer chief; Christian Scherf, DESY administrative director; Chi-Chang Kao, SLAC director; Edgar Weckert, DESY Photon Science director; David MacFarlane, SLAC chief research officer; Reinhard Brinkmann, DESY Accelerator Division director; Mark Hartney, SLAC director for strategic planning; Bill White, SLAC deputy director for LCLS Operations; Arik Willner, DESY team leader for business development; Bob Hettel, SLAC deputy ALD, Accelerator Directorate; John Galayda, SLAC project director, LCLS-II; Steven Kahn, SLAC project director, LSST. (SLAC National Accelerator Laboratory)

    SLAC and DESY share a rich history of collaboration and competition. Founded only a few years apart some 50 years ago, both centers were conceived as accelerator labs for particle physics experiments. Over the years, X-rays – an initially unwanted byproduct of particle accelerators – have become an increasingly important tool for science in both locations. Today, SLAC and DESY are multipurpose labs with similarly broad research programs, including accelerator research, particle physics, cosmology, X-ray science, bioscience, chemistry and materials science.

    Cross-fertilization between disciplines has helped both sides to stay at the forefront of science over the past decades. Similarly, developing a common strategy for cross-fertilization between the labs may further advance technologies that both research centers will need for their continued pursuit of groundbreaking science in the decades to come.

    The meeting was the first of its kind, kicking off future regular collaboration meetings of the two labs.

    SLAC and DESY will now form bilateral working groups to flesh out detailed proposals for more collaboration in the identified areas. Senior managers plan on meeting again next year, this time at DESY, to discuss the outcome of the screening process and put some of the proposals forward.

    “The meeting was very successful. It showed how much DESY and SLAC overlap in their vision of the future,” said SLAC Deputy Director Norbert Holtkamp, who set up this year’s meeting. “We now have to turn ideas on collaboration into action. Exchange of staff in strategic areas of common interest will also play an important role in this process.”

    See the full article here.

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    SLAC Campus
    SLAC is a multi-program laboratory exploring frontier questions in photon science, astrophysics, particle physics and accelerator research. Located in Menlo Park, California, SLAC is operated by Stanford University for the DOE’s Office of Science.
    i1

     
  • richardmitnick 7:24 am on July 16, 2015 Permalink | Reply
    Tags: , DESY, Helmholtz Association, , ,   

    From Helmholtz via DESY: “What is supersymmetry?” 

    DESY
    DESY

    1

    28.04.2015
    Kristine August

    Using huge particle accelerators, physicists are searching for supersymmetry.

    Supersymmetry standard model
    Standard Model of Supersymmetry

    Their existence could help us to understand the composition of dark matter. But is it possible for something to be more symmetrical than symmetrical? Wilfried Buchmüller from the Deutsches Elektronen-Synchrotron facility (DESY) explains:

    “We usually associate symmetry with spatial symmetry – in connection with an image or a form, for example. But in the standard model of physics, when we think about symmetries we are thinking about something else – the forces between particles. When, for example, the force between two matter particles remains the same after reversal of the electrical charges, we are referring to “a symmetry”.

    The various forces in the standard model possess a number of such symmetries. According to the standard model, it is valid that the smaller the gaps between the matter particles, the greater the similarity becomes between the mathematical formulas that describe the forces there. We would say here that the theory becomes more symmetrical.

    2
    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.

    Expanding on this concept, the last remaining differences are likely to cancel each other out at some point. It is our goal to describe all forces – gravity as well – and all particles on the basis of one unified principle of symmetry – supersymmetry (“SUSY”).

    But the fundamental difference still exists between matter particles and the particles that transfer forces. Although there are different types of particles, the supersymmetry theory is nevertheless able to interconnect them mathematically. We suspect that every particle has an attendant partner, a hidden supersymmetrical partner, i.e. a “superpartner”; in other words, one half of all matter is completed by its mirror image. Such a superpartner, in supersymmetrical theories, comprises the cornerstone of dark matter. Whenever the different types of particles then appear together, all of the forces become more similar to one another due to the superpartners. It is our ambition that we can also finally prove the existence of “SUSY” in reality. Namely, by finding the superpartners. They would play a key role in helping us to understand the origins of our universe.”

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    desi

    DESY is one of the world’s leading accelerator centres. Researchers use the large-scale facilities at DESY to explore the microcosm in all its variety – from the interactions of tiny elementary particles and the behaviour of new types of nanomaterials to biomolecular processes that are essential to life. The accelerators and detectors that DESY develops and builds are unique research tools. The facilities generate the world’s most intense X-ray light, accelerate particles to record energies and open completely new windows onto the universe. 
That makes DESY not only a magnet for more than 3000 guest researchers from over 40 countries every year, but also a coveted partner for national and international cooperations. Committed young researchers find an exciting interdisciplinary setting at DESY. The research centre offers specialized training for a large number of professions. DESY cooperates with industry and business to promote new technologies that will benefit society and encourage innovations. This also benefits the metropolitan regions of the two DESY locations, Hamburg and Zeuthen near Berlin.

     
  • richardmitnick 4:48 pm on July 3, 2015 Permalink | Reply
    Tags: , , DESY,   

    From DESY: “Unique Experiments at European X-Ray laser XFEL are go” 

    DESY
    DESY

    2015/06/29
    No Writer Credit

    New options for materials research, ultrafast chemistry and structural biology

    The Helmholtz Senate has given the green light for the Association’s involvement in a new kind of experimentation station at the European XFEL in Hamburg, Germany: the Helmholtz International User Consortia at the European XFEL will be funded with 30 million euro. The largest portion of the funding goes to the Helmholtz International Beamline for Extreme Fields (HIBEF), which will contribute essential components to the High-Energy Density Science (HED) instrument. Other funds go to the Serial Femtosecond Crystallography (SFX) user consortium and the h-RIXS measurement station for resonant inelastic scattering experiments. The Helmholtz-Zentrum Dresden-Rossendorf (HZDR) and the research centre DESY had applied for the funding for the international user consortia.

    DESY Helmholtz Centres & Networks

    1
    …The accelerator tunnel of European XFEL

    The goal is that, starting in 2018, the HIBEF infrastructures at HED will be used to conduct experiments under extreme conditions of high pressures, temperatures, or electromagnetic fields. The insights gleaned from these experiments will help improve models of planetary birth, among other things, and will also provide a basis for innovations in materials research and fusion technologies. “There is a great deal of interest in the joint extreme lab on the part of the international community,” says HZDR Scientific Director Prof. Roland Sauerbrey. “Some 100 institutes have already signaled their interest in our research facility.” The HZDR will be contributing a facility for materials research using high magnetic fields and a high power laser for ultrashort light pulses capable of heating electrons at the material surface to a temperature of several billion degrees Celsius. In the process, a special state of matter – a plasma, consisting of electrons and ions – is produced. An additional goal is that inside special diamond-anvil cells made by DESY, extremely high pressures of up to ten million bars and temperatures in the range of 1,500 to almost 10,000°C can be achieved.

    At the high-power laser DiPOLE, a contribution to HIBEF from Oxford University and the British science organization Science and Technology Facilities Council (STFC), matter is subjected to states of extreme pressure and temperatures on the order of several 1000°C. The states produced within the sample are similar to those found at the cores of planets. “We’re charting new scientific territory by paving the way for the types of experiments that up to now could not be performed,” says Prof. Helmut Dosch, chairman of the DESY Board of Directors, one of the consortium partners and a chief partner of the European XFEL.

    However, extreme conditions can only ever be produced for a few fractions of a second – which is why the extremely short and high-intensity X-ray laser flashes of the European XFEL lend themselves nicely to their analysis. “The new station allows us to replicate extreme conditions existing in outer space right here on Earth and examine them using X-ray laser light,” explains Prof. Massimo Altarelli, chairman of the European XFEL Management Board. “We are very pleased that potential users are highly committed to helping us build a top-notch European research facility.”

    The SFX user consortium will enable the determination of the atomic structure and function of biomolecules from extremely small crystals at the Single Particles, Clusters, and Biomolecules and Serial Femtosecond Crystallography (SPB/SFX) instrument. The structure of biomolecules is fundamentally important to their function, and decoding them is of essential importance to understanding the chemical foundations of life and numerous illnesses. Many biomolecules cannot be crystallized to a large enough extent to be successfully studied using conventional X-ray crystallography methods. With a high-throughput rate, the SPB/SFX instrument would enable such investigations. The international SFX user consortium is led by DESY and includes partners from Australia, Germany, the United Kingdom, Italy, Sweden, Slovakia, and the United States.

    With help from inelastic scattering experiments, scientists would be able to follow the steps of chemical reactions in near-real time, during which researchers would be able to observe individual types of atoms. The Heisenberg Resonant Inelastic X-Ray Scattering (h-RIXS) user consortium will contribute high-resolution spectrometers to the Spectroscopy and Coherent Scattering (SCS) instrument. The user consortium includes scientists from Germany, Finland, France, the United Kingdom, Italy, Sweden, and Switzerland.

    Geosciences, materials research, astrophysics, and plasma physics as well as structural biology and superfast chemical processes – the ultimate goal being to combine the European XFEL analytic tool with the most powerful magnetic fields currently available or experimental options of optical laser systems is to glean new insights into previously hidden processes within matter and materials. Thanks to the Helmholtz Senate’s 24 June 2015 decision, the Helmholtz stations will become reality. The final decision for the financial support remains now with the funding bodies on the federal and state level.

    See the full article here.

    Please help promote STEM in your local schools.

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    desi

    DESY is one of the world’s leading accelerator centres. Researchers use the large-scale facilities at DESY to explore the microcosm in all its variety – from the interactions of tiny elementary particles and the behaviour of new types of nanomaterials to biomolecular processes that are essential to life. The accelerators and detectors that DESY develops and builds are unique research tools. The facilities generate the world’s most intense X-ray light, accelerate particles to record energies and open completely new windows onto the universe. 
That makes DESY not only a magnet for more than 3000 guest researchers from over 40 countries every year, but also a coveted partner for national and international cooperations. Committed young researchers find an exciting interdisciplinary setting at DESY. The research centre offers specialized training for a large number of professions. DESY cooperates with industry and business to promote new technologies that will benefit society and encourage innovations. This also benefits the metropolitan regions of the two DESY locations, Hamburg and Zeuthen near Berlin.

     
  • richardmitnick 7:50 am on April 15, 2015 Permalink | Reply
    Tags: , DESY,   

    From DESY: “Discovery of a new device concept based on electronic self-organization” 

    DESY
    DESY

    April 15, 2015
    No Writer Credit

    1
    Orbital texture within an atomic layer of 1T-TaS2, as obtained by state-of-the-art density functional theory. (Credit: Authors)

    An international team of scientists from IFW Dresden, TU-Dresden, EPFL Lausanne (Switzerland), University of Illinois (US) and DESY found that the reordering of orbitals can cause a semiconductor to metal transition in nanostructures made of transition metal dichalcogenides. These orbital effects also provide an explanation for the recently discovered photoinduced semiconductor to metal transition in the transition metal dichalcogenide 1T-TaS2, indicating that these transitions can be triggered on ultrafast timescales.

    The results have been obtained by combining X-ray diffraction at DESY’s light source DORIS III with photoemission done at BESSY in Berlin, and band structure calculations performed at the IFW in Dresden. The authors present their findings in the journal “Nature Physics”.

    DESY DORIS III
    DORIS III

    BESSY II Synchrotron II
    BESSY II

    The transition metal dichalcogenides realize layered crystal structures, which make it easy to prepare them in thin-film form –an extremely advantageous feature for nanotechnology. This layered structure also causes a strongly anisotropic, quasi two-dimensional electronic structure. The latter in turn strongly favors electronic ordering instabilities and, in fact, the transition metal dichalcogenides are well known to exhibit an instability against the formation of so-called charge density waves (CDW), i.e, a crystallization of mobile electrons in the two-dimensional layers.

    Correspondingly, most of the previous research focused essentially isolated two-dimensional layers. However, drastic changes of the X-ray diffraction pattern of the CDW measured at the DORIS III beamline BW5, revealed that this may not be sufficient and that correlations between layers need also to be considered. Indeed the electronic structure calculations uncovered complex orbital textures (see figure), which are interwoven with the CDW order and cause dramatic differences in the electronic structure depending on the alignment of the orbitals between neighboring planes.

    2
    The switching between metastable orbital orders corresponding to the semiconducting (top) and metallic state (bottom). (Copyright: Nature Physics)

    The new twist of the paper is the discovery that these orbital-mediated interactions may enable to drive semiconductor to metal transitions with technologically pertinent gaps and on ultrafast timescales. This opens up new routes to fabricate optically switchable devices based on orbitally textured CDW compounds, a new technology that could be called “Orbitronics”.

    These discoveries are hence of special relevance for the ongoing development of novel, miniaturized and ultrafast devices for electronic and sensing applications. They also enable to explain a number of long-standing puzzles associated with the electronic self-organization in 1T-TaS2: the ultrafast response to optical excitations, the high sensitivity to pressure and a mysterious commensurate phase that is commonly thought to be a special phase (‘Mott phase’) and that is not found in any other isostructural modification.

    Charge density wave states have recently also been observed in a large number of cuprate high-Tc superconductors and their relation to other phases like the pseudo gap, the anti-ferro magnetic phase and superconductivity is currently under debate. To elucidate the role played by the orbital degree of freedom for superconductivity will be another challenge.

    (from authors)

    Publication:

    „Orbital textures and charge density waves in transition metal dichalcogenides“, T. Ritschel, J. Trinckauf, K. Koepernik, B. Büchner, M. v. Zimmermann, H. Berger, Y. I. Joe, P. Abbamonte and J. Geck, Nature Physics (2015), DOI: 10.1038/nphys3267

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    desi

    DESY is one of the world’s leading accelerator centres. Researchers use the large-scale facilities at DESY to explore the microcosm in all its variety – from the interactions of tiny elementary particles and the behaviour of new types of nanomaterials to biomolecular processes that are essential to life. The accelerators and detectors that DESY develops and builds are unique research tools. The facilities generate the world’s most intense X-ray light, accelerate particles to record energies and open completely new windows onto the universe. 
That makes DESY not only a magnet for more than 3000 guest researchers from over 40 countries every year, but also a coveted partner for national and international cooperations. Committed young researchers find an exciting interdisciplinary setting at DESY. The research centre offers specialized training for a large number of professions. DESY cooperates with industry and business to promote new technologies that will benefit society and encourage innovations. This also benefits the metropolitan regions of the two DESY locations, Hamburg and Zeuthen near Berlin.

     
  • richardmitnick 9:09 am on April 10, 2015 Permalink | Reply
    Tags: , DESY,   

    From DESY: “Gamma-ray bursts as cosmic particle accelerators” 

    DESY
    DESY

    2015/04/10
    No Writer Credit

    1

    Study provides new insights into the universe’s most powerful explosions

    A new study provides detailed insight into the most powerful explosions in the universe: gamma-ray bursts. The simulation explains the modes of particle acceleration in these rare events better than previous models and can explain conflicting astrophysical observations. Scientists from DESY and two US universites present their work in the journal Nature Communications.

    Gamma-ray bursts happen when extremely massive stars go supernova. These explosions can be seen nearly across the whole visible universe, up to several billion lightyears. The giant stars’ strong magnetic fields channel most of the explosion’s energy into two powerful jets of electrically charged gas (plasma), one at each magnetic pole. These plasma jets are powerful natural particle accelerators.

    Scientists expect the plasma jets to be a significant source of cosmic rays, high-energy subatomic particles (mostly protons) that constantly pepper Earth’s atmosphere from space. These particles can have up to ten million times the energy of the protons in the Large Hadron Collider (LHC), currently the most powerful particle accelerator on Earth at the European particle physics laboratory CERN.

    But if gamma-ray bursts are a significant source of cosmic rays, scientists expect them for physics reasons to also shed a large number of light elementary particles called neutrinos. The IceCube observatory at the South Pole, in which DESY is the main European partner, is looking for exactly those high-energy cosmic neutrinos.

    ICECUBE neutrino detector
    IceCube neutrino detector interior
    IceCube

    However, none have been detected so far from gamma-ray bursts. This means that at least ten times fewer neutrinos reach us from gamma-ray bursts than were expected. “This throws up new questions for theory,” says DESY scientist Walter Winter, a co-author of the new study. “Perhaps, our concept of gamma-ray bursts was too simple.”

    2
    The plasma is ejected in shells at different speeds. When the shells collide, particles are accelerated. Illustration: Mauricio Bustamante/DESY

    3
    Neutrinos are mainly generated at lower distance from the source, cosmic rays at medium distance and gamma-rays at greater distance. Illustration Mauricio Bustamante/DESY

    Existing models of these powerful explosions assumed that cosmic rays, neutrinos and gamma-rays all come from the same region within the plasma jets. The team of theoretical astroparticle physicists, including Winter from DESY, Mauricio Bustamante from Ohio State University and Philipp Baerwald and Kohta Murase from Pennsylvania State University, has now developed a more dynamic model of gamma-ray bursts. According to this model, the plasma is ejected in the form of shells at different speed. In considerable distance from the source, these shells collide, thereby accelerating particles.

    This approach can not only explain the observed strong variations in the light curves of gamma-ray bursts. A consequence of this model is also that neutrinos, cosmic rays and gamma-rays must be produced in completely different regions of the jets. This can explain, why the expected flux of neutrinos could not be found. “We expect that the next generation of neutrino telescopes, such as IceCube-Gen-2, will be sensitive to this minimal flux that we’re predicting”, says Bustamante. In contrast to earlier models, this estimate is more robust and does only weakly depend on the characteristics of individual gamma-ray bursts.

    Reference:
    Neutrino and Csomic-Ray Emission from Multiple Internal Shocks In Gamma-Ray Bursts; Mauricio Bustamante, Philipp Baerwald, Kohta Murase & Walter Winter; „Nature Communications“, 2015; DOI: 10.1038/ncomms7783

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

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    desi

    DESY is one of the world’s leading accelerator centres. Researchers use the large-scale facilities at DESY to explore the microcosm in all its variety – from the interactions of tiny elementary particles and the behaviour of new types of nanomaterials to biomolecular processes that are essential to life. The accelerators and detectors that DESY develops and builds are unique research tools. The facilities generate the world’s most intense X-ray light, accelerate particles to record energies and open completely new windows onto the universe. 
That makes DESY not only a magnet for more than 3000 guest researchers from over 40 countries every year, but also a coveted partner for national and international cooperations. Committed young researchers find an exciting interdisciplinary setting at DESY. The research centre offers specialized training for a large number of professions. DESY cooperates with industry and business to promote new technologies that will benefit society and encourage innovations. This also benefits the metropolitan regions of the two DESY locations, Hamburg and Zeuthen near Berlin.

     
  • richardmitnick 8:30 am on March 27, 2015 Permalink | Reply
    Tags: , , , DESY,   

    From DESY: “Negotiations for CTA northern site to start” 

    DESY
    DESY

    2015/03/26
    No Writer Credit

    Cherenkov Telescope Array
    Proposed Cherenkov Telescope Array for hunting Gamma Rays

    On 26 March 2015, the partner countries of Cherenkov Telescope Array (CTA) have decided to start negotiations for the location of the telescope array in the northern hemisphere. At a meeting in Heidelberg representatives of ministries and funding agencies have decided to begin negotiations with Spain for a possible location on La Palma and Mexico for one in San Pedro Mártir. Another candidate site in Arizona (USA) is considered as a possible back-up site.

    “I appreciate that we have successfully chosen the northern candidate sites with whom we would like to start negotiations as soon as possible,” said Beatrix Vierkorn-Rudolph from the German Federal Ministry of Research and Education, chair of the CTA Resource Board, after the decision of the voting members representing Argentina, Austria, Brazil, Czech Republic, France, Germany, Italy, Japan, Poland, South Africa, Spain, Switzerland and the UK. After negotiations, the Board will select the final site in November 2015. In regards to the southern hemisphere site, negotiations with the candidates Namibia and Chile are progressing and are expected to end in August 2015. Christian Stegmann from DESY added: “I’m very much looking forward to the final site decisions later this year; scientists worldwide are eager to see CTA advancing towards implementation.”

    Currently in its pre-construction phase, determining the northern and southern hemisphere sites will be a critical step towards the realization of the Cherenkov Telescope Array. “I’m looking forward to converging on final designs for the telescope arrays now that negotiations will start with specific locations in mind,” said Christopher Townsley, CTA project manager. Following the site selection, the project will move forward with construction of the first telescopes on site planned for 2016.

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    desi

    DESY is one of the world’s leading accelerator centres. Researchers use the large-scale facilities at DESY to explore the microcosm in all its variety – from the interactions of tiny elementary particles and the behaviour of new types of nanomaterials to biomolecular processes that are essential to life. The accelerators and detectors that DESY develops and builds are unique research tools. The facilities generate the world’s most intense X-ray light, accelerate particles to record energies and open completely new windows onto the universe. 
That makes DESY not only a magnet for more than 3000 guest researchers from over 40 countries every year, but also a coveted partner for national and international cooperations. Committed young researchers find an exciting interdisciplinary setting at DESY. The research centre offers specialized training for a large number of professions. DESY cooperates with industry and business to promote new technologies that will benefit society and encourage innovations. This also benefits the metropolitan regions of the two DESY locations, Hamburg and Zeuthen near Berlin.

     
  • richardmitnick 3:35 pm on March 25, 2015 Permalink | Reply
    Tags: , DESY, ,   

    From DESY: “Latest result from neutrino observatory IceCube opens up new possibilities for particle physics” 

    DESY
    DESY

    2015/03/24
    No Writer Credit

    South Pole detector measures neutrino oscillations with high precision

    The South Pole observatory IceCube has recorded evidence that elusive elementary particles called neutrinos changing their identity as they travel through the Earth and its atmosphere.

    1
    The IceCube laboratory at the Scott Amundsen South Pole station hosts the computers collecting the detector data (picture: Felipe Pedreros. IceCube/NSF)

    IceCube neutrino detector interior
    IceCube Neutrino Experiment interior

    The observation of these neutrino oscillations, first announced in 1998 by the Super Kamiokande experiment in Japan, opens up new possibilities for particle physics with the Antarctic telescope that was originally designed to detect neutrinos from faraway sources in the cosmos.

    Super-Kamiokande experiment Japan
    Super Kamiokande experiment

    “We are very pleased that the IceCube detector with its DeepCore array can be used to observe neutrino oscillations with high precision,” says Olga Botner, Spokesperson of the IceCube experiment. “DeepCore was designed on the initiative of Per Olof Hulth who sadly passed away recently, to significantly lower IceCube’s energy threshold. The results show that IceCube can contribute to nailing down the oscillation parameters and motivate us to pursue our plans for an IceCube upgrade called PINGU to measure neutrino properties.”

    IceCube DeepCore
    IceCube DeepCore

    IceCube PINGU
    IceCube PINGU

    “IceCube records over one hundred thousand atmospheric neutrinos every year, most of them muon neutrinos produced by the interaction of fast cosmic particles with the atmosphere,” says Rolf Nahnhauer, leading scientist at DESY. The subdetector DeepCore allows for detecting neutrinos with energies down to 10 giga-electronvolts (GeV). “According to our understanding of neutrino oscillations, IceCube should see fewer muon neutrinos at energies around 25 GeV that reach IceCube after crossing the entire Earth,” explains Rolf Nahnhauer. “The reason for these missing muon neutrinos is that they oscillate into other types.” IceCube researchers selected Northern Hemisphere muon neutrino candidates with energies between a few GeV and around 50 GeV from data taken between May 2011 and April 2014. About 5200 events were found, much below the 7000 expected in the non-oscillations scenario.

    Neutrinos remain the most mysterious of the known elementary particles. Postulated by Austrian physicist Wolfgang Pauli in 1930, it took 25 years for their experimental detection. “Neutrinos are elusive,” says Olga Botner, ” and can travel through an enormous amount of material, even the whole Earth, without interacting.” Nevertheless, physicists have built more and more sophisticated instruments to reveal the mysteries of this very light particles. One of the surprising results was that the three different types of neutrinos, electron, muon and tau neutrinos, can change their identity, transforming from one type of neutrino to another. This phenomenon is known as neutrino oscillation. “Neutrino oscillations are only possible if neutrinos have a mass,” explains Nahnhauer. “On the other hand, massive neutrinos are not explained within the otherwise so successful Standard Model of particle physics.”

    3
    Standard Model of Particle Physics. The diagram shows the elementary particles of the Standard Model (the Higgs boson, the three generations of quarks and leptons, and the gauge bosons), including their names, masses, spins, charges, chiralities, and interactions with the strong, weak and electromagnetic forces. It also depicts the crucial role of the Higgs boson in electroweak symmetry breaking, and shows how the properties of the various particles differ in the (high-energy) symmetric phase (top) and the (low-energy) broken-symmetry phase (bottom).

    The strength of the oscillation and the distances over which it develops depend on two parameters: the so-called mixing angle and the mass difference. The values of these parameters have been constrained by precise measurements of neutrinos from the sun, the atmosphere, nuclear reactors, and particle accelerators.

    The IceCube neutrino observatory at the South Pole has already demonstrated that it is a powerful tool to explore the universe by neutrinos, using the Antarctic ice sheet as its detection material. An array of more than 5000 optical sensors distributed in a cubic kilometer of the ice records the very rare collisions of neutrinos. And less than two years ago, IceCube physicists announced the discovery of the first high-energy neutrinos from the cosmos, acknowledged as “breakthrough of the year” by the journal Physics World.

    Now IceCube has proven that it can also deliver top particle physics results. The new measurement by the IceCube collaboration resulting in significantly improved constraints on the neutrino oscillation parameters has been accepted for publication by the scientific journal Physical Review D.

    Three years of IceCube data yielded a similar precision to that reached from about 15 years of Super-Kamiokande data. In contrast to the purified water in Super-Kamiokande’s 50-kiloton vessel, IceCube uses a natural target material, the glacier ice at the South Pole. IceCube’s 500 times larger observation volume produces larger event statistics in shorter times. “Both Super-Kamiokande and IceCube use the same ‘beam‘ which is atmospheric neutrinos, but at different energies. And we reach similar precision of the measurable oscillation parameters,” says Juan Pablo Yanez, postdoctoral researcher at DESY, who is the corresponding author of the paper. “The results now derived from IceCube data show errors still larger than, but already comparable to the most precise neutrino beam experiments MINOS and T2K. But as IceCube keeps taking data and improving the analyses we are hopeful to catch up soon.” adds Yanez.

    Currently the scientists are planning an upgrade of the IceCube detector called PINGU (Precision IceCube Next Generation Upgrade). A much higher density of optical modules in the whole central region will improve the sensitivity to several fundamental questions associated with neutrinos.

    “In particular we want to measure the so called neutrino mass hierarchy – whether there are two heavier neutrinos and one light one, or whether it is the other way around.” explains Rolf Nahnhauer. “This is important to understand how neutrinos obtain masses, but also has significant relevance on how the cosmos evolves. The current results provide an important experimental confirmation that our concepts work.“

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    desi

    DESY is one of the world’s leading accelerator centres. Researchers use the large-scale facilities at DESY to explore the microcosm in all its variety – from the interactions of tiny elementary particles and the behaviour of new types of nanomaterials to biomolecular processes that are essential to life. The accelerators and detectors that DESY develops and builds are unique research tools. The facilities generate the world’s most intense X-ray light, accelerate particles to record energies and open completely new windows onto the universe. 
That makes DESY not only a magnet for more than 3000 guest researchers from over 40 countries every year, but also a coveted partner for national and international cooperations. Committed young researchers find an exciting interdisciplinary setting at DESY. The research centre offers specialized training for a large number of professions. DESY cooperates with industry and business to promote new technologies that will benefit society and encourage innovations. This also benefits the metropolitan regions of the two DESY locations, Hamburg and Zeuthen near Berlin.

     
  • richardmitnick 9:20 am on March 13, 2015 Permalink | Reply
    Tags: , DESY, ,   

    From DESY: “Molecules perform endless cartwheels” 

    DESY
    DESY

    2015/03/13
    No Writer Credit

    1
    An near-infrared laser (red) makes the originally disordered molecules perform synchronized cartwheels so that all the molecules at a particular position along the beam are oriented in the same direction. Picture: Jens S. Kienitz/CFEL, DESY and CUI

    Scientists in Hamburg have resorted to a physical trick to persuade entire groups of molecules to perform synchronized cartwheels, virtually endlessly. This technique opens up new opportunities for imaging molecules and their chemical dynamics. Prof. Jochen Küpper and his team at the Center for Free-Electron Laser Science (CFEL) are presenting their findings in the journal Physical Review Letters.

    2
    The FLASH experimental hall with beamlines which guide the laser-like light of the free-electron laser FLASH to the experimental stations. (Source: DESY)

    Intense flashes of x-rays emitted by so-called free electron lasers offer detailed insights into the world of molecules. Researchers use them, for example, to explore the atomic structure of biomolecules and to better understand their function, or they try to film dynamic processes taking place in the nanocosm – such as the excitation cycle in photosynthesis. Until now, however, such molecules have generally had to be available in a crystalline form for such examinations to be carried out, because the individual molecules alone do not produce a strong enough signal. In a crystal, the molecules are arranged in regular patterns so that the signals from each add up, allowing an analysis on an atomic level.

    “Crystals represent a very special state, however – often imposed and unnatural”, explains Sebastian Trippel, the first author of the paper. Scientists would therefore often prefer to examine free molecules directly. But how can such free molecules be moved, in a controlled fashion, into the x-ray beam of a free electron laser? Scientists have been experimenting with different methods of guiding the molecules, using electromagnetic fields and laser light, and aligning them in a particular direction at the same time.

    They have already succeeded in strongly orienting entire ensembles of molecules in the same direction for such examinations, “however when you do this, the molecular ballet is influenced by an electromagnetic field, which can in turn have an unwanted effect on the measurements,” explains Jochen Küpper, a scientist at DESY, who is also a member of the Hamburger Center for Ultrafast Imaging (CUI) and a professor at the University of Hamburg. The molecular tamers working with Küpper have now found a way of preserving the alignment of molecular ensembles even after the laser field has been switched off.

    For their test, the researchers used carbonyl sulfide (OCS) as a simple model system. The three atoms that make up this molecule (carbon, oxygen and sulfur) lie in a straight line, and this simple structure makes it particularly suitable for demonstrating the method. The scientists released high-pressure carbonyl sulfide molecules into a vacuum chamber through a fine nozzle, as a result of which the gas expanded and thereby cooled down rapidly. They then used a so-called deflector, a kind of prism for molecules, to fish out those molecules that were in the lowest-energy state.

    A tailored pulse of infrared laser light mixed this state with the first excited quantum state. As a result, the molecules started to perform, synchronously, a so-called inversion, whereby the individual molecules fell in step with each other, so that the sulphur atom (S) of the molecules all simultaneously pointed up or down. This inversion continued undiminished even after the molecules had passed the infrared laser and were moving through space without being affected by an alternating electromagnetic field. “In a sense, the laser forces the molecules to perform synchronous cartwheels, which would continue forever if they didn’t eventually reach the walls of the experimental apparatus”, Trippel explains.

    The molecules travel an almost infinite distance compared with the period of their inversion – they have enough time to perform hundreds of thousands of cycles of this motion before they collide with the wall of the vacuum chamber. For experimenters, this offers some very tangible advantages: all they have to do in order to select a specific orientation of the molecular ensemble under scrutiny – in which the two orientations alternate regularly – is to select the appropriate moment in time behind the laser beam.

    This method not only works for the two lowest energy states, but in principle for all states of a linear molecule, as the researchers point out in their paper. “This targeted molecular choreography opens up new possibilities for holding ensembles of free molecules in the x-ray beam of a free electron laser in a controlled fashion, so that they can be investigated there,” says Küpper.

    Reference:
    Two-state wave packet for strong field-free molecular orientation; Sebastian Trippel, Terry Mullins, Nele L. M. Müller, Jens S. Kienitz, Rosario González-Férez and Jochen Küpper; Physical Review Letters, 2015; DOI: 10.1103/PhysRevLett.114.103003

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    desi

    DESY is one of the world’s leading accelerator centres. Researchers use the large-scale facilities at DESY to explore the microcosm in all its variety – from the interactions of tiny elementary particles and the behaviour of new types of nanomaterials to biomolecular processes that are essential to life. The accelerators and detectors that DESY develops and builds are unique research tools. The facilities generate the world’s most intense X-ray light, accelerate particles to record energies and open completely new windows onto the universe. 
That makes DESY not only a magnet for more than 3000 guest researchers from over 40 countries every year, but also a coveted partner for national and international cooperations. Committed young researchers find an exciting interdisciplinary setting at DESY. The research centre offers specialized training for a large number of professions. DESY cooperates with industry and business to promote new technologies that will benefit society and encourage innovations. This also benefits the metropolitan regions of the two DESY locations, Hamburg and Zeuthen near Berlin.

     
  • richardmitnick 3:32 pm on February 11, 2015 Permalink | Reply
    Tags: , DESY, X-ray Lasers,   

    From DESY: “Taking high-speed snapshots of living cells with an X-ray laser” 

    DESY
    DESY

    2015/02/11

    X-ray imaging method captures living cells with unprecedented speed and resolution

    An international team led by Uppsala University and including scientists from DESY and the European XFEL has for the first time successfully imaged whole living bacterial cells with an X-ray laser. The method used in this experiment can produce results that are of higher spatial and temporal resolution than even the best optical microscopy techniques, with the added possibility of creating detailed 3D models of the cells. “When you really want to understand the details of a cell’s functions, you need it alive”, says Uppsala University Professor Janos Hajdu, one of the lead researchers in the experiment and an advisor to European XFEL. The technique, as described in the journal Nature Communications, allows scientists a clearer view into the complicated world of the cell.

    1
    Reconstructed electron density of a cyanobacterium. Credit: Gjis van der Schot/Universität Uppsala

    The method involves spraying the cells into a fine aerosol ahead of the pulses of an X-ray laser. This aerosol — literally a beam of living cells — has a thickness less than that of a human hair. The ultra-short X-ray pulses scatter from the individual cells and the resulting diffraction patterns are picked up by a detector. Computer programs, including several developed in collaboration between Uppsala and DESY, analyze the data and reconstruct the image of the cells.

    “While the X-rays destroy the cells in the process, an X-ray laser’s ultra-short flashes and high intensity allow the diffraction data to be captured quickly enough to get an accurate picture of the sample before it disintegrates. The flashes outrun the damage,” says Anton Barty, a DESY scientist at the Center for Free Electron Laser Science who is also a co-author of this paper.

    This technique, called “diffraction-before-destruction”, has been proven to work in several studies with biological and also with inorganic samples before. The cell imaging experiment took place at the LCLS X-ray laser at SLAC National Accelerator Laboratory in Menlo Park, California. Two types of cyanobacteria were used in the study called Cyanobium gracile and Synechococcus elongatus. These cells have a roughly cylindrical shape that is immediately apparent in the reconstructions from the diffraction data.

    2
    Nomarski image of the same cyanobacterium, calculated from the recontruction. Credit: Gjis van der Schot/Universität Uppsala

    However, the leader of the experiment, Tomas Ekeberg, an assistant professor in molecular biophysics at Uppsala University, acknowledged that the pictures could have been even better but the data were more than the detectors could handle.

    “We so far can only accurately reconstruct to 76 nanometres resolution, but the data we collected indicates that we can get down to 4 nanometres, which is the size of a protein molecule”, Ekeberg says. A nanometre is a billion times smaller than a metre. The reason for the drop in resolution was what amounted to an overexposure, just like too bright of a light in a photograph. “This experiment was a proof-of-concept study”, says Ekeberg. “We will be able to obtain much higher-resolution pictures when we can use a filter to help reduce the overexposure.” adds Gijs van der Schot, a Ph.D. student with Ekeberg and the first author on the paper.

    Acquiring high-resolution micrographs from cells in conventional experiments has usually meant long exposure times and about a million times higher radiation doses than the dose that kills a living cell. As a consequence, much of what we know today about cells at high-resolution comes from dead material. The team’s new method can access the structure of living cells at practically instantaneous speeds, before radiation damage has time to set in. Each image is formed in femtoseconds. A femtosecond is a millionth of a billionth of a second. Such a revolutionary tool could help scientists better understand some of the mysteries of cellular function and behaviour. Additionally, this technique opens the door for future 3D modelling of cells and cellular activities, and provides key insights to fundamental processes in several important areas of disease research.

    3
    X-ray diffraction pattern produced by a cyanobacterium at the LCLS. Credit: Gjis van der Schot/Universität Uppsala

    “This is a promising method for the European XFEL”, says Joachim Schulz, a scientist at European XFEL and one of the co-authors on the paper. “It could further expand the application of bio-imaging methods to users, opening possibilities to image living organisms.”

    The team plans to fine-tune the imaging method with further experiments and work on consistently developing images at higher resolution. Additionally, Ekeberg and van der Schot predict that future studies would attempt to develop the 3D cell division models or target particular structural information about the cells for bioinformatics.

    “The contrast is tremendous between images produced using this technique and those from traditional optical microscopy of living cells”, says Hajdu. “Few believed this was possible.”

    The future for imaging is getting even brighter in Hamburg, as the European X-FEL will soon start generating ultra-short, ultra-intense X-ray pulses at 300 times higher repetition rate than the best X-ray lasers today.

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    desi

    DESY is one of the world’s leading accelerator centres. Researchers use the large-scale facilities at DESY to explore the microcosm in all its variety – from the interactions of tiny elementary particles and the behaviour of new types of nanomaterials to biomolecular processes that are essential to life. The accelerators and detectors that DESY develops and builds are unique research tools. The facilities generate the world’s most intense X-ray light, accelerate particles to record energies and open completely new windows onto the universe. 
That makes DESY not only a magnet for more than 3000 guest researchers from over 40 countries every year, but also a coveted partner for national and international cooperations. Committed young researchers find an exciting interdisciplinary setting at DESY. The research centre offers specialized training for a large number of professions. DESY cooperates with industry and business to promote new technologies that will benefit society and encourage innovations. This also benefits the metropolitan regions of the two DESY locations, Hamburg and Zeuthen near Berlin.

     
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