Oxford Physics Newsletter
Total Page：16
File Type：pdf, Size：1020Kb
Spring 2011, Number 1 Department of Physics Newsletter elcome to the first edition of Oxford Physics creates new solar-cell the Department technology Wof Physics Newsletter. In this takes place to generate free electrons, which edition, we describe some of Henry Snaith contribute to a current in an external circuit. The the wide range of research original dye-sensitised solar cell used a liquid currently being carried out in The ability to cheaply and efficiently harness the power of electrolyte as the “p-type” material. the Oxford Physics Department, the Sun is crucial to trying to slow The work at Oxford has focused on effectively and also describe some of down climate change. Solar cells replacing the liquid electrolyte with p-type the other activities where we aim to produce electricity directly from sunlight, organic semiconductors. This solid-state system seek to engage the public in but are currently too expensive to have significant offers great advantages in ease of processing and impact. A new “spin-out” company, Oxford science and communicate with scalability. Photovoltaics Ltd, has recently been created to potential future physicists. I commercialise solid-state dye-sensitised solar Over the next two to three years, Oxford hope you enjoy reading it. If you cell technology developed at the Clarendon Photovoltaics will scale the technology from laboratory to production line, with the projected have passed through Oxford Laboratory. market being photovoltaic cells integrated into Physics as an undergraduate In conventional photovoltaics, light is absorbed windows and cladding for buildings. or postgraduate student, or in in the bulk of a slab of semiconducting material any other capacity, we would and the photogenerated charge is collected at metallic electrodes. The materials used in the welcome future contributions new dye-sensitised technology do not perform from you. Please contact well as solid films: however, by creating a multi- [email protected] component nanostructured composite, where each component has a specific functionality, very Lance Miller effective solar cells can be created. The basic technology operates by a principle INSIDE THIS EDITION: similar to the initial stages of photosynthesis in plants. Light is absorbed in a dye molecule located 1 Solar-cell technology at the junction between an n-type metal oxide and a p-type organic semiconductor. Following Solar cells created by Oxford Photovoltaics can be ATLAS at CERN light absorption, photoinduced charge transfer printed onto glass or other surfaces 2 First results from Planck Climate change 3 LHCb at CERN ATLAS closes in on Supersymmetry Industrial news from Atomic heavy partner particles that would be produced & Laser Physics Alan Barr in the proton-proton collisions at the LHC. Such 4 Superconductivity The Large Hadron Collider at CERN particles will rapidly decay, leading to distinctive 5 Biological imaging operated extremely successfully final states involving “missing” momentum – the during 2010. The Oxford group result of unobserved, weakly interacting massive 6 40 Years of Oxford in Space – which has had an impressive particles (WIMPs). Quantum information record during the design, construction and Continued on page 2... technologies in Europe commissioning phases of the ATLAS experiment – is now leading many aspects of the ATLAS physics 7 DNA nanotechnology analysis programme. Our recent results include 8 Citizen science investigations into proton structure, the physics of electroweak bosons and strong interactions, Higgs 10 Outreach and education boson searches, and searches for new “exotic” 11 People at Oxford Physics particles. Some of the most interesting recent results include our first searches for Supersymmetric particles. Supersymmetric theories predict the existence of ATLAS Experiment www.physics.ox.ac.uk 2011 CERN © SCIENCE NEWS www.physics.ox.ac.uk/research First results from Planck Charmaine Armitage-Caplan, are Joanna Dunkley involved in analysis for both of The start of Planck’s scientific instruments. this year saw Planck not only sees the relic the first results signal from the Big Bang in the released from distant background, but also ESA’s Planck satellite. Measuring a wealth of microwave signals tiny fluctuations in the Cosmic from our own Milky Way, and Microwave Background (CMB) from more distant galaxies. These radiation, Planck’s goals include first results focus on this set of investigating the very first “foreground” signals. Billions of moments in the universe, and light years away, Planck has found better understanding the origin a new set of massive clusters of of cosmic structure. Launched galaxies, the largest structures in May 2009 together with the in the universe. They are rare Herschel observatory, Planck and their number is a sensitive Planck has taken a closer look at to several tens of billions times a scans the microwave sky from a probe of the expansion rate of the almost 1000 clumps of the very second by collisions. stable point a million miles from universe, and how much matter it cold dust that represent the first Earth. It is the successor to NASA’s Planck now continues to survey contains. Planck has also seen the stages of star-birth in our own WMAP satellite, observing the the universe, with the next data gas and dust from distant galaxies galaxy. The new data also provides anisotropies in the CMB with release due early 2013, promising in which stars are born, telling us stronger evidence for the origins higher resolution and improved exciting cosmological results. about when and where the first of a diffuse glow in the Milky Way, sensitivity. Researchers at stars formed in the universe. Much coming from dust grains spun up Oxford, Jo Dunkley, Joe Silk and more locally, within the Milky Way, ATLAS closes in on Climate change and extreme weather probed by Supersymmetry citizen science Continued from page 1... In collaboration with our As was said in the press release, “whether or not a Myles Allen ATLAS colleagues, we flood occurs in any given year is still an ‘Act of God’, have produced the world’s but we are beginning to see how human influence Greenhouse gas emissions due most sensitive searches for on climate may be starting to load God’s dice”. to human activity substantially Supersymmetry. The new increased the odds of damaging Members of the public can still participate in follow- results represent a significant floods occurring in England and up studies looking at other weather events: more squeeze on the allowed model Wales in autumn 2000 according to new research by details are at http://weatherathome.org. A report space – indeed they start to Oxford Physics graduate student Pardeep Pall and of the research, “Anthropogenic greenhouse gas eat away at the region for co-authors. contribution to flood risk in England and Wales in which the Supersymmetric The floods of autumn 2000 damaged nearly 10,000 autumn 2000”, was published in the journal Nature WIMP could explain the properties, with insured losses estimated at £1.3 on 17 February 2011. cosmological dark matter. The theory is still far from billion. Using a detailed computer climate model, the www.ox.ac.uk/media/news_stories/2011/110216.html team simulated the weather in autumn 2000, both as excluded, but it is rewarding it was, and as it might have been had there been no to see that even with our first greenhouse gas emissions since the beginning of the data-set, and with (so far) half 20th century. This was then repeated thousands of of the design beam energy, times, using a global volunteer network of personal we can meaningfully constrain computers participating in the climateprediction. the space of interesting net project, to pin down the impact of emissions models. At the time of writing on extreme weather. The team fed the output from we have just started the 2011 these weather simulations into a flood model, and run, during which we expect found that 20th century greenhouse gas emissions to increase the number of roughly doubled the odds of floods occurring in proton-proton collisions by a autumn 2000. factor of about 100. Floods in south Oxford in 2003 2 | Department of Physics Newsletter | Spring 2011 SCIENCE NEWS www.physics.ox.ac.uk/research Industrial news LHCb comes of age from Atomic & Every prestigious career starts to K–π+; see figure below. This Laser Physics Malcolm John with a promising debut and LHCb has been measured by two older Paul Ewart Over 18 years has displayed exactly that during experiments running for most the winter conference season. of the last decade. LHCb has has passed since An initiative launched in With the data accumulated achieved this result with just two the concept of a June 2010 to establish closer during just a couple of months months of running! B-meson detector collaboration between Oxford of concentrated running last at the Large Hadron Collider One of the strongest statements University and BP has led to autumn, a slew of results are now (LHC) was first presented at CERN. from B-physics will come from the a contract between BP and available for public digestion. “LHCb”, as it became known, has observed enhancement (or not) researchers in ALP and Oxford grown from hand-drawn sketches The first result was measurements of the rate that B-mesons decay to Engineering Science (Prof to a fully functioning, state-of- of heavy-quark production in just two muons. In the Standard Richard Stone). the-art experiment that is rapidly the new TeV energy regime. The Model this is predicted to occur The project will exploit a demonstrating its scientific merit. b-quark cross section turned three times in a billion, whereas novel method for measuring out similar to prediction but the Supersymmetry might increase In the 7 TeV proton-proton gas temperatures developed corresponding result for charm this by a factor of 10.