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  • richardmitnick 1:44 pm on April 4, 2020 Permalink | Reply
    Tags: "Artificial fog helps lasers shine brighter", A team led by the EU Graphene Flagship with collaborators including Imperial have invented a diffuser that scatters laser light making it more useful in lighting larger areas., ICL-Imperial College London   

    From Imperial College London: “Artificial fog helps lasers shine brighter” 

    Imperial College London
    From Imperial College London

    03 April 2020
    Hayley Dunning

    1
    The ‘fog’ in action. Credit: Florian Rasch
    Laser-based lights could replace lightbulbs thanks to an artificial ‘fog’ that scatters laser light, producing high brightness at low power.

    The new and improved laser-based lights could be used anywhere from indoor lighting and projectors to car headlights and outdoor floodlights. As they produce high brightness at low power, they would be more energy-efficient than regular lightbulbs or LEDs.

    Current uses of laser light are limited to a single colour and the light is very focused and narrow – for example in laser pointers, barcode scanners and DVD players.

    Now, a team led by the EU Graphene Flagship with collaborators including Imperial have invented a diffuser that scatters laser light, making it more useful in lighting larger areas.

    The study, published in Nature Communications, also shows how the laser light can be tuned to different colours, including white, which has been difficult to achieve with lasers.

    More than 99.99% air

    Previously laser-based lights, called laser diodes (LDs), have created white light by shining a laser onto phosphor materials, but the process is not very efficient and can only create one colour of light.

    The team invented a new way to create white light, by shining red, blue and green lasers into a diffuser made of hexagonal boron nitride (hBN), an ultrathin material related to graphene.

    The diffuser, called aero-BN, is made of a semi-transparent web of randomly arranged and interconnected hBN hollow microtubes, and consists of more than 99.99% air. The three coloured laser beams penetrate deeply into the diffuser, where they are strongly and randomly scattered multiple times by the nanoscopic walls of the microtubes.

    3
    Graphical representation of the Aero-BN diffuser exposed to three lasers beams. Credit: F. Schütt

    In this way, the diffuser acts like an artificial fog, making the light more diffuse. At an optimum intensity of all three lasers, white light is emitted, and by varying the ratio of intensity of the coloured lasers, this method allows for the choice of a rainbow palette of colours.

    Enormous range of applications

    Co-author of the study Dr Felice Torrisi, from the Department of Chemistry at Imperial, said: “We have shown that hexagonal boron nitride flakes can be assembled into a micro-scaffold that converts laser light into a white light source suitable for low-power and high-intensity lighting applications, just like lightbulbs, with the advantage of operating across all the visible colours.

    “We are currently looking into applying this technology for future high-brightness and low-power illumination systems, with an enormous range of applications from indoor lighting to aerospace.”

    The high degree of scattering inside the fog also reduces the problem of ‘speckle’ – a contrast pattern usually caused by LDs that is uncomfortable for human vision, making it unsuitable for lighting applications. In the artificial fog, a large number of speckle patterns were superimposed and averaged out, so that they became invisible to the human eye.

    Professor Xinliang Feng, the Graphene Flagship’s Work Package Leader for Functional Foams and Coatings, said: “This is an excellent example of how we can utilise the functionality of layered materials on the macroscopic scale. The foam is capable of withstanding extremely high-powered lasers, allowing for the creation of small-scale light sources with extremely high intensities.”

    See the full article here .


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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Imperial College London is a science-based university with an international reputation for excellence in teaching and research. Consistently rated amongst the world’s best universities, Imperial is committed to developing the next generation of researchers, scientists and academics through collaboration across disciplines. Located in the heart of London, Imperial is a multidisciplinary space for education, research, translation and commercialisation, harnessing science and innovation to tackle global challenges.

     
  • richardmitnick 11:47 am on December 20, 2019 Permalink | Reply
    Tags: "High performance computing is part of our vital research infrastructure”, ICL-Imperial College London   

    From Imperial College London: “High performance computing is part of our vital research infrastructure” 

    Imperial College London
    From Imperial College London

    20 December 2019
    Elizabeth Nixon

    1
    Imperial has invested £15m to support the expansion of the Research Computing Service.

    High performance computing (HPC) is fast confirming its place as a vital tool for researchers at the College. It allows individual computers to work together to analyse data that is too large for a single desktop to handle.

    Imperial’s Research Computing Service provides access to powerful computing resources, expert consultancy and training for all researchers. Over 1,800 staff and postgraduate students across the College have used the service over the past year, supported by a team of software engineers, specialist trainers and systems analysts.

    The number of staff and students using the service has increased by 35 per cent over the past two years. Advances in areas such as machine learning, electronic records and genomics have led to an increase in registered users from the Faculty of Medicine and the Business School in particular.

    Professor Nick Jennings, Imperial’s Vice-Provost for Research and Enterprise, has championed the need for central institutional support for the service. He said: “We often think of infrastructure in terms of buildings and labs, but in the modern world high performance computing is part of the vital infrastructure that underpins our research.

    “Access to high capacity computing resources is increasingly vital across growing and emerging research areas such as machine learning and genomics. The investment we’ve made means that we have a largest active user community and one of the largest facilities of any UK university.”

    Imperial has committed to an ongoing investment of £3 million per year to expand the service to meet demand, and to keep it free at the point of use for researchers.

    Professor Spencer Sherwin, Director of the Research Computing Service, said: “Different disciplines value different aspects of our service. We’re tailoring it to meet this range of needs, not only in terms of the actual hardware and software, but also in the support and training we offer.”

    Below we hear from three regular users of the service.
    Dr David Orme, Research Fellow, Department of Life Sciences

    Dr Orme works on species diversity and uses computer models to explore spatial data – like species’ range maps.

    He said: “Ecological research using ‘big data’ is becoming more common. An individual researcher might be able to afford one powerful workstation, but computing resources are then the bottleneck in research. The Research Computing Service allows us to get answers much more quickly and provides the power to solve difficult problems but, probably more importantly, also makes it possible to do more data exploration and more careful research.”

    Dr Kim Jelfs, Senior Lecturer, Department of Chemistry

    Dr Jelfs uses computational approaches to enable the discovery of functional molecular materials.

    She said: “Every member of my group uses the Research Computing Service on a daily basis to run computationally intensive calculations. Not only do we need to run parallel calculations, but my group’s research is also focused upon high throughput screening, where we need to run tens of thousands of calculations to screen candidate materials before we analyse them for functionality.”

    Dr Antonio Berlanga-Taylor, Research Fellow, School of Public Health

    Dr Berlanga-Taylor studies the interaction of our genes and the environment in disease development.

    He said: “Genomics simply wouldn’t exist without research computing resources such as those provided by Imperial. I study large cohorts with multiple measurements that amount to hundreds of millions of observations. Answering research questions based on these data requires not only high performance computing but also data storage alongside the expertise and person-power that the Service provides.”

    See the full article here .


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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Imperial College London

    Imperial College London is a science-based university with an international reputation for excellence in teaching and research. Consistently rated amongst the world’s best universities, Imperial is committed to developing the next generation of researchers, scientists and academics through collaboration across disciplines. Located in the heart of London, Imperial is a multidisciplinary space for education, research, translation and commercialisation, harnessing science and innovation to tackle global challenges.

     
  • richardmitnick 9:37 am on December 19, 2019 Permalink | Reply
    Tags: "Ultrashort x-ray technique will probe conditions found at the heart of planets", , , , , , ICL-Imperial College London, , ,   

    From Imperial College London and STFC: “Ultrashort x-ray technique will probe conditions found at the heart of planets” 


    From Science and Technology Facilities Council

    and

    Imperial College London
    From Imperial College London

    19 December 2019
    Hayley Dunning

    1
    Working with the Gemini Laser. Credit: STFC

    Combining powerful lasers and bright x-rays, Imperial and STFC researchers have demonstrated a technique that will allow new extreme experiments.

    The new technique would be able to use a single x-ray flash to capture information about extremely dense and hot matter, such as can be found inside gas giant planets or on the crusts of dead stars.

    The same conditions are also found in fusion experiments, which are trying to create a new source of energy that mimics the Sun.

    ______________________________________
    We will now be able to probe warm dense matter much more efficiently and in unprecedented resolution.
    Dr Brendan Kettle
    ______________________________________

    The technique, reported this week in Physical Review Letters, was developed by a team led by Imperial College London scientists working with colleagues including those at the UK’s Central Laser Facility at the Science and Technology Facilities Council (STFC) Rutherford Appleton Laboratory [below], and was funded by the European Research Council.

    The researchers wanted to improve ways to study ‘warm dense matter’ – matter that has the same density as a solid, but is heated up to 10,000?C. Researchers can create warm dense matter in the lab, recreating the conditions in the hearts of planets or crucial for fusion power, but it is difficult to study.

    Accelerating discoveries

    The team used the Gemini Laser, which has two beams – one which can create the conditions for warm dense matter, and one which can create ultrashort and bright x-rays to probe the conditions inside the warm dense matter.

    2
    STFC Gemini Laser

    Previous attempts using lower-powered lasers required 50-100 x-ray flashes to get the same information that the new technique can gain in just one flash. The flashes last only femtoseconds (quadrillionths of a second), meaning the new technique can reveal what is happening within warm dense matter across very short timescales.

    First author Dr Brendan Kettle, from the Department of Physics at Imperial, said: “We will now be able to probe warm dense matter much more efficiently and in unprecedented resolution, which could accelerate discoveries in fusion experiments and astrophysics, such as the internal structure and evolution of planets including the Earth itself.”

    The technique could also be used to probe fast-changing conditions inside new kinds of batteries and memory storage devices.

    Answering key questions

    In the new study, the team used their technique to examine a heated sample of titanium, successfully showing that it could measure the distribution of electrons and ions.

    Lead researcher Dr Stuart Mangles, from the Department of Physics at Imperial, said: “We are planning to use the technique to answer key questions about how the electrons and ions in this warm dense matter ‘talk’ to each other, and how quickly can energy transfer from the electrons to the ions.”

    The Central Laser Facility’s Gemini Laser is currently one of the few places the right conditions for the technique can be created, but as new facilities start operating around the world, the team hope the technique can be expanded and used to do a whole new class of experiments.

    Dr Rajeev Pattathil, Gemini Group Leader at the Central Laser Facility, said: “With ultrashort x-ray flashes we can get a freeze-frame focus on transient or dynamic processes in materials, revealing key new fundamental information about materials here and in the wider Universe, and especially those in extreme states.”

    See the full article here .


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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Imperial College London

    Imperial College London is a science-based university with an international reputation for excellence in teaching and research. Consistently rated amongst the world’s best universities, Imperial is committed to developing the next generation of researchers, scientists and academics through collaboration across disciplines. Located in the heart of London, Imperial is a multidisciplinary space for education, research, translation and commercialisation, harnessing science and innovation to tackle global challenges.

    STFC-Science and Technology Facilities Council

    STFC Hartree Centre

    STFC Rutherford Appleton Laboratory at Harwell in Oxfordshire, UK

    Helping build a globally competitive, knowledge-based UK economy

    We are a world-leading multi-disciplinary science organisation, and our goal is to deliver economic, societal, scientific and international benefits to the UK and its people – and more broadly to the world. Our strength comes from our distinct but interrelated functions:

    Universities: we support university-based research, innovation and skills development in astronomy, particle physics, nuclear physics, and space science
    Scientific Facilities: we provide access to world-leading, large-scale facilities across a range of physical and life sciences, enabling research, innovation and skills training in these areas
    National Campuses: we work with partners to build National Science and Innovation Campuses based around our National Laboratories to promote academic and industrial collaboration and translation of our research to market through direct interaction with industry
    Inspiring and Involving: we help ensure a future pipeline of skilled and enthusiastic young people by using the excitement of our sciences to encourage wider take-up of STEM subjects in school and future life (science, technology, engineering and mathematics)

    We support an academic community of around 1,700 in particle physics, nuclear physics, and astronomy including space science, who work at more than 50 universities and research institutes in the UK, Europe, Japan and the United States, including a rolling cohort of more than 900 PhD students.

    STFC-funded universities produce physics postgraduates with outstanding high-end scientific, analytic and technical skills who on graduation enjoy almost full employment. Roughly half of our PhD students continue in research, sustaining national capability and creating the bedrock of the UK’s scientific excellence. The remainder – much valued for their numerical, problem solving and project management skills – choose equally important industrial, commercial or government careers.

    Our large-scale scientific facilities in the UK and Europe are used by more than 3,500 users each year, carrying out more than 2,000 experiments and generating around 900 publications. The facilities provide a range of research techniques using neutrons, muons, lasers and x-rays, and high performance computing and complex analysis of large data sets.

     
  • richardmitnick 1:38 pm on August 22, 2019 Permalink | Reply
    Tags: "Quantum computing race needs ‘global effort’ says Provost", ICL-Imperial College London, The UK has a decades-long head start in quantum technologies.   

    From Imperial College London: “Quantum computing race needs ‘global effort’, says Provost” 

    Imperial College London
    From Imperial College London

    21 August 2019
    Andrew Scheuber

    1
    NQIT https://nqit.ox.ac.uk/

    The race for a viable quantum computer – “the most exciting in science today” – needs enormous collaborations, Professor Ian Walmsley argues.

    Writing in today’s Financial Times, Imperial’s Provost notes that “The complexity of some of the hurdles are arguably more challenging than those that were solved at the Large Hadron Collider, the world’s most powerful atom smasher. Disparate networks of researchers, entrepreneurs, capital and governments will have to compete and collaborate all over the world.

    “Yet too much commentary, especially in the UK and Europe, fixates on where quantum innovation and commercialisation is happening.”

    This so-called “brain drain” argument is “nonsense”, he writes. “It misunderstands the global nature of science and innovation, and underplays the UK’s exceptional strengths in quantum technology.”

    Welcoming competition

    He argues that “We should welcome, not fear, competition, as well as being open to collaboration. From lunar exploration to cancer research, it’s how the best science and innovation comes to life.”

    Professor Walmsley, a quantum physicist, also serves as Director of the UK’s Networked Quantum Information Technologies Hub.

    He observes that “the UK has a decades-long head start in quantum technologies. Consistent support from research councils and university departments have spurred crucial breakthroughs. These leaps in fundamental science — all from British laboratories — are the foundation of today’s global industry. It is what has drawn pioneers in quantum metrology such as Ed Hinds back to the UK from the US.

    “The British government’s foresight in founding the National Quantum Technologies Programme six years ago accelerated research and development, and stimulated private investment. Total UK government investment has now reached £1bn.”

    The full opinion piece can be read in the Financial Times.

    See the full article here .


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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Imperial College London

    Imperial College London is a science-based university with an international reputation for excellence in teaching and research. Consistently rated amongst the world’s best universities, Imperial is committed to developing the next generation of researchers, scientists and academics through collaboration across disciplines. Located in the heart of London, Imperial is a multidisciplinary space for education, research, translation and commercialisation, harnessing science and innovation to tackle global challenges.

     
  • richardmitnick 12:22 pm on August 19, 2019 Permalink | Reply
    Tags: , , , , , ICL-Imperial College London   

    From Imperial College London: “Lab-based dark energy experiment narrows search options for elusive force” 

    Imperial College London
    From Imperial College London

    19 August 2019
    Hayley Dunning

    1
    No image caption or credit.

    An experiment to test a popular theory of dark energy has found no evidence of new forces, placing strong constraints on related theories.

    Dark energy is the name given to an unknown force that is causing the universe to expand at an accelerating rate.

    Some physicists propose dark energy is a ‘fifth’ force that acts on matter, beyond the four already known – gravitational, electromagnetic, and the strong and weak nuclear interactions.

    However, researchers think this fifth force may be ‘screened’ or ‘hidden’ for large objects like planets or weights on Earth, making it difficult to detect.

    Now, researchers at Imperial College London and the University of Nottingham have tested the possibility that this fifth force is acting on single atoms, and found no evidence for it in their most recent experiment.

    This could rule out popular theories of dark energy that modify the theory of gravity, and leaves fewer places to search for the elusive fifth force.

    Finding the fifth force

    The experiment, performed at Imperial College London and analysed by theorists at the University of Nottingham, is reported today in Physical Review Letters.

    Professor Ed Copeland, from the Centre for Astronomy & Particle Physics at the University of Nottingham, said: “This experiment, connecting atomic physics and cosmology, has allowed us to rule out a wide class of models that have been proposed to explain the nature of dark energy, and will enable us to constrain many more dark energy models.”

    The experiment tested theories of dark energy that propose the fifth force is comparatively weaker when there is more matter around – the opposite of how gravity behaves.

    This would mean it is strong in a vacuum like space, but is weak when there is lots of matter around. Therefore, experiments using two large weights would mean the force becomes too weak to measure.

    Experiment with a single atom

    The researchers instead tested a larger weight with an incredibly small weight – a single atom – where the force should have been observed if it exists.

    The team used an atom interferometer to test whether there were any extra forces that could be the fifth force acting on an atom. A marble-sized sphere of metal was placed in a vacuum chamber and atoms were allowed to free-fall inside the chamber.

    The theory is, if there is a fifth force acting between the sphere and atom, the atom’s path will deviate slightly as it passes by the sphere, causing a change in the path of the falling atom. However, no such force was found.

    Professor Ed Hinds, from the Department of Physics at Imperial, said: “It is very exciting to be able to discover something about the evolution of the universe using a table-top experiment in a London basement.”

    See the full article here .


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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Imperial College London

    Imperial College London is a science-based university with an international reputation for excellence in teaching and research. Consistently rated amongst the world’s best universities, Imperial is committed to developing the next generation of researchers, scientists and academics through collaboration across disciplines. Located in the heart of London, Imperial is a multidisciplinary space for education, research, translation and commercialisation, harnessing science and innovation to tackle global challenges.

     
  • richardmitnick 4:36 pm on December 14, 2018 Permalink | Reply
    Tags: , , , , , ICL-Imperial College London, ,   

    From Imperial College London: “Young star caught forming around another star” 

    Imperial College London
    From Imperial College London

    14 December 2018
    Hayley Dunning

    1
    A small star has been observed forming out of the dust surrounding a larger star, in a similar way to how planets are born.

    Astronomers were observing the formation of a massive young star, called MM 1a, when they discovered an unexpected object nearby.

    MM 1a is surrounded by rotating disc of gas and dust. But orbiting just beyond this disc, they discovered a faint object they called MM 1b, which they discovered was a smaller star. MM 1b is believed to have formed out of the gas and dust surrounding the larger MM 1a.

    The team of astronomers, led by the University of Leeds and including an Imperial College London researcher, have published their discovery today in the journal Astrophysical Journal Letters.

    Co-author Dr Thomas Haworth, from the Department of Physics at Imperial, helped predict what might be observed around MM 1a, and then to interpret what they actually found. He said: “It’s great when the new data surprises you, which was definitely the case here.

    “Seeing the disc itself in so much detail is exciting, but detecting a second star forming within the disc, perhaps in a similar way to how planets form, was a huge unexpected bonus. There is a lot of work ahead of us to fully understand the consequences of this new discovery.”

    An entirely different formation process

    Stars form within large clouds of gas and dust in interstellar space. When these clouds collapse under gravity, they begin to rotate faster, forming a disc around them. It is in these discs that planets can form around low mass stars like our Sun.

    Lead author Dr John Ilee, from the School of Physics and Astronomy at the University of Leeds, said: “In this case, the star and disc we have observed is so massive that, rather than witnessing a planet forming in the disc, we are seeing another star being born.”

    By measuring the amount of radiation emitted by the dust and subtle shifts in the frequency of light emitted by the gas, the researchers were able to calculate the mass of MM 1a and MM 1b.

    They found that MM 1a weighs 40 times the mass of our Sun. The smaller orbiting star MM 1b was calculated to weigh less than half the mass of our Sun.

    2
    Observation of the dust emission (green) and hot gas rotating in the disc around MM 1a (red is receding gas, blue is approaching gas). MM 1b is seen the lower left. Credit: J. D. Ilee / University of Leeds.

    Dr Ilee said: “Many older massive stars are found with nearby companions. But these ‘binary’ stars are often very equal in mass, and so likely formed together as siblings. Finding a young binary system with a mass ratio of 80:1 is very unusual, and suggests an entirely different formation process for both objects.”

    The team believe stars like MM 1b could form in the outer regions of cold, massive discs. These discs are unable to hold themselves up against the pull of their own gravity, collapsing into one or more fragments.

    The team believe their discovery is one of the first examples of a ‘fragmented’ disc to be detected around a massive young star.

    Only a million years to live

    Dr Duncan Forgan, a co-author from the Centre for Exoplanet Science at the University of St Andrews, added: “I’ve spent most of my career simulating this process to form giant planets around stars like our Sun. To actually see it forming something as large as a star is really exciting.”

    The researchers note that newly discovered young star MM 1b could also be surrounded by its own disc, which may have the potential to form planets of its own – but it will need to be quick.

    Dr Ilee added: “Stars as massive as MM 1a only live for around a million years before exploding as powerful supernovae, so while MM 1b may have the potential to form its own planetary system in the future, it won’t be around for long.”

    The astronomers made this surprising discovery by using a unique new instrument situated high in the Chilean desert – the Atacama Large Millimetre/submillimetre Array (ALMA).

    ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres

    Using the 66 individual dishes of ALMA together in a process called interferometry, the astronomers were able to simulate the power of a single telescope nearly 4km across, allowing them to image the material surrounding the young stars for the first time.

    Funders for this research include the Science and Technologies Facilities Council (UK) and the European Research Council.

    See the full article here .


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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Imperial College London

    Imperial College London is a science-based university with an international reputation for excellence in teaching and research. Consistently rated amongst the world’s best universities, Imperial is committed to developing the next generation of researchers, scientists and academics through collaboration across disciplines. Located in the heart of London, Imperial is a multidisciplinary space for education, research, translation and commercialisation, harnessing science and innovation to tackle global challenges.

     
  • richardmitnick 3:34 pm on August 9, 2018 Permalink | Reply
    Tags: , , ICL-Imperial College London, Mini antimatter accelerator could rival the likes of the Large Hadron Collider, , ,   

    From Imperial College London: “Mini antimatter accelerator could rival the likes of the Large Hadron Collider” 

    Imperial College London
    From Imperial College London

    09 August 2018
    Hayley Dunning

    1
    Simulation of groups of positrons being concentrated into a beam and accelerated. No image credit .

    Researchers have found a way to accelerate antimatter in a 1000x smaller space than current accelerators, boosting the science of exotic particles.

    The new method could be used to probe more mysteries of physics, like the properties of the Higgs boson and the nature of dark matter and dark energy, and provide more sensitive testing of aircraft and computer chips.

    The method has been modelled using the properties of existing lasers, with experiments planned soon. If proven, the technology could allow many more labs around the world to conduct antimatter acceleration experiments.

    Particle accelerators in facilities such as the Large Hadron Collider (LHC) in CERN and the Linac Coherent Light Source (LCLS) at Stanford University in the United States, speed up elementary particles like protons and electrons.

    LHC

    CERN map


    CERN LHC Tunnel

    CERN LHC particles

    SLAC/LCLS

    These accelerated particles can be smashed together, as in the LHC, to produce particles that are more elementary, like the Higgs boson, which gives all other particles mass.

    They can also be used to generate x-ray laser light, such as in the LCLS, which is used to image extremely fast and small process, like photosynthesis.

    Shrinking accelerators to fit in a lab

    However, to get to these high speeds, the accelerators need to use equipment that is at least two kilometres long. Previously, researchers at Imperial College London had invented a system that could accelerate electrons using equipment only meters long.

    Now a researcher at Imperial has invented a method of accelerating the antimatter version of electrons – called positrons – in a system that would be just centimetres long.

    The accelerator would require a type of laser system that currently covers around 25 square metres, but that is already present in many physics labs.

    Dr Aakash Sahai, from the Department of Physics at Imperial reported his method today in the Physical Review Journal for Accelerators and Beams. He said: “With this new accelerator method, we could drastically reduce the size and the cost of antimatter acceleration. What is now only possible by using large physics facilities at tens of million-dollar costs could soon be possible in ordinary physics labs.”

    “The technologies used in facilities like the Large Hadron Collider or the Linac Coherent Light Source have not undergone significant advances since their invention in the 1950s [not true, HL-LHC and LCLS II are on the way] . They are expensive to run, and it may be that we will soon have all we can get out of them [not true].

    “A new generation of compact, energetic and cheap accelerators of elusive particles would allow us to probe new physics – and allow many more labs worldwide to join the effort.”

    Creating ‘Higgs factories’ and testing aircraft

    While the method is currently undergoing experimental validation, Dr Sahai is confident it will be possible to produce a working prototype within a couple of years, based on the Department’s previous experience creating electron beams using a similar method.

    The method uses lasers and plasma – a gas of charged particles – to produce, concentrate positrons and accelerate them to create a beam. This centimetre-scale accelerator could use existing lasers to accelerate positron beams with tens of millions of particles to the same energy as reached over two kilometres at the Stanford accelerator.

    Colliding electron and positron beams could have implications in fundamental physics. For example, they could create a higher rate of Higgs bosons than the LHC can, allowing physicists to better study its properties. They could also be used to look for new particles thought to exist in a theory called ‘supersymmetry’, which would fill in some gaps in the Standard Model of particle physics.

    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.


    Standard Model of Particle Physics from Symmetry Magazine

    3
    No image caption or credit.

    The positron beams would also have practical applications. Currently, when checking for faults and fracture risks in materials such as aircraft bodies, engine blades and computer chips, x-rays or electron beams are used. Positrons interact in a different way with these materials than x-rays and electrons, providing another dimension to the quality control process.

    Dr Sahai added: “It is particularly gratifying to do this work at Imperial, where our lab’s namesake – Professor Patrick Blackett – won a Nobel Prize for his invention of methods to track exotic particles like antimatter. Professor Abdus Salam, another Imperial academic, also won a Nobel Prize for the validation of his theory of weak force made possible only using a pre-LHC positron-electron collider machine at CERN. It’s wonderful to attempt to carry on this legacy.”

    See the full article here .

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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    Imperial College London

    Imperial College London is a science-based university with an international reputation for excellence in teaching and research. Consistently rated amongst the world’s best universities, Imperial is committed to developing the next generation of researchers, scientists and academics through collaboration across disciplines. Located in the heart of London, Imperial is a multidisciplinary space for education, research, translation and commercialisation, harnessing science and innovation to tackle global challenges.

     
  • richardmitnick 12:42 am on May 13, 2018 Permalink | Reply
    Tags: , ICL-Imperial College London, , , , X-rays from tabletop lasers allows scientists to peer through the ‘water window’   

    From Imperial College London: “X-rays from tabletop lasers allows scientists to peer through the ‘water window’” 

    Imperial College London
    From Imperial College London

    11 May 2018
    Hayley Dunning

    1

    Studying the fleeting actions of electrons in organic materials will now be much easier, thanks to a new method for generating fast X-rays.

    The technique means advanced measurements of fast reactions will now be possible in physics labs around the world, without having to wait to use expensive and scarce equipment. It could be used, for example, to study and improve light-harvesting technologies like solar panels and water splitters.

    When ‘soft’ X-rays, beyond the range of ultraviolet light, strike an object, they are strongly absorbed by some kinds of atoms and not others. In particular, water is transparent to these X-rays, but carbon absorbs them, making them useful for imaging organic and biological materials.

    However, a challenge has been to generate very fast soft X-rays. Creating pulses of X-rays that only last one thousandth of a millionth of a millionth of a second would allow researchers to image the extremely quick motions of electrons, crucial for determining how charge travels and reactions occur.

    Smallest and fastest reaction steps

    Fast soft X-rays have been created with large facilities, such as multi-billion dollar costing free-electron lasers, but now a research team from Imperial College London have generated fast and powerful fast soft X-ray pulses using standard laboratory lasers.

    The method, which can produce bright soft X-ray pulses that last hundreds of attoseconds (quintillionths of a second), is published today in Science Advances.

    With the new technique, researchers will be able to watch the movement of electrons on their natural timescale, giving them a dynamic picture of the smallest and fastest reaction steps.

    Senior author Professor Jon Marangos, from the Department of Physics at Imperial, said: “The strength of this technique is that it can be used by many physics labs around the world with lasers they already have installed.

    “This discovery will allow us to make measurements at extreme timescales for the first time. We are at the frontiers of what we can measure, seeing faster-than-ever processes important for science and technology.”

    Generating X-rays

    Generating X-rays in a lab requires exciting atoms until they release photons – particles of light. Normally, atoms in a long, dispersed cloud are excited in sequence so that they emit photons in ‘phase’, meaning they add up and create a stronger X-ray pulse. This is known as phase matching.

    But when trying to generate soft X-rays this way, effects in the cloud of atoms strongly defocus the laser, disrupting phase matching.

    Instead, the team discovered that they needed a thin, dense cloud of atoms and short laser pulses. With this setup, while the photons could not stay in phase over a long distance, they were still in phase over a shorter distance and for a short time. This led to unexpectedly efficient production of the short soft X-ray pulses.

    The team further measured and simulated the exact effects that cause high harmonic generation in this situation, and from this were able to predict the optimum laser conditions for creating a range of X-rays.

    Lead researcher Dr Allan Johnson, from the Department of Physics at Imperial, said: “We’ve managed to look inside what was before the relatively black-box of soft X-ray generation, and use that information to build an X-ray laser on a table that can compete with football-field spanning facilities. Knowledge is quite literally power in this game.”

    Improving solar technologies

    The team at Imperial plan to use the technique to study organic polymer materials, in particular those that harvest the Sun’s rays to produce energy or to split water. These materials are under intense study as they can provide cheaper renewable energy.

    However, many currently used materials are unstable or inefficient, due to the action of electrons that are excited by light. Closer study of the fast interactions of these electrons could provide valuable insights into methods for improving solar cells and catalysts.

    • ‘High-Flux Soft X-ray Harmonic Generation from Ionization-Shaped Few-Cycle Laser Pulses’ by Allan S. Johnson, Dane R. Austin, David A. Wood, Christian Brahms, Andrew Gregory, Konstantin B. Holzner, Sebastian Jarosch, Esben W. Larsen, Susan Parker, Christian S. Strüber, Peng Ye, John W. G. Tisch, and Jon P. Marangos is published in Science Advances.

    See the full article here .

    Please help promote STEM in your local schools.

    stem

    Stem Education Coalition

    Imperial College London

    Imperial College London is a science-based university with an international reputation for excellence in teaching and research. Consistently rated amongst the world’s best universities, Imperial is committed to developing the next generation of researchers, scientists and academics through collaboration across disciplines. Located in the heart of London, Imperial is a multidisciplinary space for education, research, translation and commercialisation, harnessing science and innovation to tackle global challenges.

     
  • richardmitnick 2:39 pm on December 7, 2017 Permalink | Reply
    Tags: A space mission to test how objects fall in a vacuum has released its first results providing an improved foundation for Einstein's famous theory, , , , , , , ICL-Imperial College London, , , The theory is fundamentally incompatible with another well-tested theory: quantum mechanics which describes the physics of the extremely small, The theory of general relativity and the conclusions it draws about gravity have been shown to be true wherever tested, This first result is going to shake the world of physics and will certainly lead to a revision of alternative theories to general relativity   

    From ICL: “European satellite confirms general relativity with unprecedented precision” 

    Imperial College London
    Imperial College London

    07 December 2017
    Hayley Dunning

    A space mission to test how objects fall in a vacuum has released its first results, providing an improved foundation for Einstein’s famous theory.

    The first results of the ‘Microscope’ satellite mission were announced this week by a group of researchers led by the French space agency CNES and including Imperial scientists. The findings are published in the journal Physical Review Letters.

    CNES Microscope satellite

    Launched in April 2016, the mission set out to test the ‘equivalence principle’, the founding assumption of Einstein’s theory of general relativity. The theory poses that gravity is not a ‘pulling’ force, but is the result of large bodies, like the Earth, bending spacetime.

    As a result, when two objects are dropped in a vacuum under the same force of gravity, they fall at the same rate, no matter what their difference in weight or composition. This principle was demonstrated by Apollo 15 astronaut David Scott, who dropped a hammer and a feather on the Moon and showed them both reaching the ground at the same time.

    However, dropping household objects on the lunar surface does not allow very precise measurements – it could be that they reach the ground fractions of a second apart. This is important for scientists to know, because if the equivalence principle does not hold absolutely, then it could provide clues to a unifying theory of physics.

    Finding a single theory

    The theory of general relativity, and the conclusions it draws about gravity, have been shown to be true wherever tested. However, the theory is fundamentally incompatible with another well-tested theory: quantum mechanics, which describes the physics of the extremely small.

    The major goal for 21st Century physics is a single theory that ties them all together neatly. Certain candidate theories predict that the equivalence principle may be violated at very weak levels.

    The new results have measured the equivalence principle with ten times the precision of any previous experiment, and show that objects in a vacuum fall with the same acceleration.

    Professor Timothy Sumner, from the Department of Physics at Imperial was involved in the early discussions for the project thirty years ago, which led to the current mission. He more recently joined the Science Working Team. Commenting on the latest results, he said: “The equivalence principle has proven unshakeable yet again.

    “This result is the first new measurement for several years and demonstrates the possibility of taking such difficult ‘laboratory’ experiments into the quiet and interference-free space environment. There will more results from this impressive experiment.”

    1,900 orbits of the Earth

    To test the principle, the Microscope satellite contains a series of ‘test masses’: blocks of metals of different weights with very precisely measured properties. These masses are isolated from any other influence and are monitored as they freefall in space while orbiting the Earth.

    This means their acceleration due to the freefall can be measured and compared to test the equivalence principle. If two test masses of equal size but different composition are accelerated differently during the freefall, then the equivalence principle is violated.

    The science phase of the mission began in December 2016 and has already collected data from 1,900 orbits of the Earth. This means that altogether the objects have been freefalling in space for the equivalent of 85 million kilometres, or half the Earth-Sun distance.

    The mission’s principle investigator, Pierre Touboul from France’s national aerospace research centre, ONERA, said: “The satellite’s performance is far exceeding expectations. Data from more than 1,900 additional orbits are already available and more are to come.

    “This first result is going to shake the world of physics and will certainly lead to a revision of alternative theories to general relativity.”

    The Microscope experiment is continuing to collect data, and the team hope that the final analysis will have a precision within a tenth of a trillionth of a percent.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    Imperial College London

    Imperial College London is a science-based university with an international reputation for excellence in teaching and research. Consistently rated amongst the world’s best universities, Imperial is committed to developing the next generation of researchers, scientists and academics through collaboration across disciplines. Located in the heart of London, Imperial is a multidisciplinary space for education, research, translation and commercialisation, harnessing science and innovation to tackle global challenges.

     
  • richardmitnick 6:07 am on October 25, 2017 Permalink | Reply
    Tags: , , , Herbivores help protect marine ecosystems from climate change, ICL-Imperial College London   

    From ICL: “Herbivores help protect marine ecosystems from climate change” 

    Imperial College London
    Imperial College London

    25 October 2017
    Hayley Dunning

    1
    A limpet on seaweed. Image: Rebecca Kordas

    Plant-eating critters are key to helping ecosystems survive global warming, offering some hope for a defence strategy against climate change.

    An international research team created miniature marine ecosystems and tested how they fared in warmer conditions. They found that in the hottest conditions, ecosystems that included limpets – voracious snail-like marine herbivores – fared the best.

    The study, published in Science Advances, monitored mini ecosystems on rocky shores made up of different collections of organisms. The ecosystems were grown on special hard plastic plates that could be individually warmed. This allowed the researchers to test how the different ecosystems responded to temperature rises while in their natural habitat.

    Ecosystems are in a delicate balance: removing organisms that do key jobs can cause the whole system to deteriorate. If this ecosystem is then put under stress, it is less able to cope and can collapse.

    In these experiments, it was the key job performed by the main herbivore (limpets) that helped the ecosystems stay resilient in the face of warming. Limpets are voracious consumers of algae, and their action prevents algae from building up and using all the available space – a valuable resource on rocky shores.

    Variety needed

    Lead author of the study Dr Rebecca Kordas, who completed this research for her PhD at the University of British Columbia and is now a research fellow at Imperial College London, said: “The herbivores created space for other plants and animals to move in and we saw much more diversity and variety in these ecosystems.

    “We want variety because we found it helps protect the ecosystem when you add a stressor like heat.”

    2
    The experimental plates underwater. Image: Rebecca Kordas

    The research team studied life in the intertidal zone, the area of the shore between the low tide and high tide, on the coast of British Columbia. This area is home to a community of starfish, anemones, mussels, barnacles and seaweed. As the tide moves in and out, the plants and animals must cope with huge variation in temperature every day, sometimes as much as 20 to 25 degrees Celsius.

    Despite dealing daily with these extremes, the ecosystems can be severely damaged by further warming. Dr Kordas said: “When heat waves come through British Columbia and the Pacific Northwest, we see mass mortality of numerous intertidal species.

    “These creatures are already living at their physical limits, so a two-degree change – a conservative prediction of the warming expected over the next 80 years or so – can make a big difference.”

    Making ecosystems more resilient

    The researchers found that in the summer, when temperatures were at their warmest, communities could fare well even if they were heated, but only if limpets were present. Dr Kordas added: “When limpets were part of the community, the effects of warming were less harsh.”

    3
    Plates along the shore in Ruckle Park, British Columbia. Image: Rebecca Kordas

    Senior study author Professor Christopher Harley from the University of British Columbia says that, in general – consumers like limpets, sea otters or starfish are very important to maintaining biodiversity, especially in aquatic ecosystems. Losing these species can destabilize ecosystems, but protecting them can make ecosystems more resilient.

    “We should be thinking of ways to reduce our negative effects on the natural environment and these results show that if we do basic conservation and management, it can make a big difference in terms of how ecosystems will weather climate change,” Professor Harley said.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    Imperial College London

    Imperial College London is a science-based university with an international reputation for excellence in teaching and research. Consistently rated amongst the world’s best universities, Imperial is committed to developing the next generation of researchers, scientists and academics through collaboration across disciplines. Located in the heart of London, Imperial is a multidisciplinary space for education, research, translation and commercialisation, harnessing science and innovation to tackle global challenges.

     
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