CERN: Experiments updates https://home.cern/ en CLOUD at CERN reveals a new mechanism behind urban smog https://home.cern/news/news/experiments/cloud-cern-reveals-new-mechanism-behind-urban-smog <span>CLOUD at CERN reveals a new mechanism behind urban smog</span> <span><span lang="" about="/user/139" typeof="schema:Person" property="schema:name" datatype="">ssanchis</span></span> <span>Tue, 05/12/2020 - 18:26</span> <div class="field field--name-field-p-news-display-listing-img field--type-image field--label-hidden field--item"> <img src="/sites/home.web.cern.ch/files/2020-05/CLOUD_picture_1.png" width="906" height="350" alt="An illustration of atmospheric inhomogeneities in a megacity, showing “Large Eddy Simulations” of Hong Kong superimposed on a composite London skyline. The resulting inhomogeneities in ammonia and nitric acid vapours can drive particle growth rates to up to more than 100 times faster than previously seen. (Credit: Helen Cawley)" typeof="foaf:Image" class="img-responsive" /> </div> <div class="field field--name-field-p-news-display-caption field--type-string-long field--label-hidden field--item">An illustration of atmospheric inhomogeneities in a megacity, showing “Large Eddy Simulations” of Hong Kong superimposed on a composite London skyline. The resulting inhomogeneities in ammonia and nitric acid vapours can drive particle growth rates to up to more than 100 times faster than previously seen.(Credit: Helen Cawley)</div> <div class="field field--name-field-p-news-display-body field--type-text-long field--label-hidden field--item"><p>The CLOUD collaboration has revealed a new mechanism that drives winter smog episodes in cities. The results, <a href="https://www.nature.com/articles/s41586-020-2270-4">published yesterday in the journal <em>Nature</em></a>, could help inform policies for reducing urban particle pollution, which ranks fifth in the risk factors for mortality worldwide.</p> <p>Winter urban smog episodes occur when new particles form in polluted air trapped below a temperature inversion. The warm air above the inversion inhibits convection, causing pollution to build up near the ground. However, how additional aerosol particles manage to form and grow in this highly polluted air has been a mystery until now, because they should be rapidly lost through scavenging by pre-existing aerosols. A new result from CLOUD could explain the mystery.</p> <p>The CLOUD experiment (Cosmics Leaving Outdoor Droplets) at CERN involves a special cloud chamber capable of mimicking all the diverse aspects of Earth’s atmosphere, with precise control of the conditions and extremely low contaminants. Data from sampling instruments attached to the chamber allow a comprehensive understanding of the formation of aerosol particles and their effect on clouds and climate. Ions from cosmic rays can also influence aerosol formation, and their contributions are studied by varying the intensity of a pion beam from CERN’s Proton Synchrotron, which passes through the chamber.</p> <p>In their new study, CLOUD scientists simulated polluted urban conditions in the chamber and investigated the role of ammonia and nitric acid at atmospheric concentrations. Global emissions of ammonia are dominated by farming. In cities, however, the presence of both ammonia and nitric acid – which derives from nitrogen oxides (NOx) - is largely due to vehicles.</p> <p>"Ammonia and nitric acid were previously thought to play a passive role in particle formation, simply exchanging with ammonium nitrate in the particles”, says Jasper Kirkby, head of the CLOUD experiment.</p> <p>However, the new CLOUD study showed that small inhomogeneities in the concentrations of ammonia and nitric acid - which only persist for a few minutes - can lead to particle growth rates up to more than 100 times faster than previously seen, but only in short spurts that have escaped detection so far. These ultrafast growth rates are sufficient to rapidly transform the newly formed particles to larger size, where they are less prone to being lost through scavenging by pre-existing particles. The end result is a dense smog episode with a high number of particles.</p> <p>“Although the emission of nitrogen oxides is regulated, ammonia emissions are not and may even be increasing with the latest catalytic converters used in gasoline and diesel vehicles. Our study shows that regulating ammonia emissions from vehicles could contribute to reducing urban smog,” concludes Jasper Kirkby.</p> <figure class="cds-video" id="CERN-VIDEO-2020-023-001"><div><iframe allowfullscreen="true" frameborder="0" height="450" src="//cds.cern.ch/video/CERN-VIDEO-2020-023-001?responsive=1" width="100%"></iframe></div> <figcaption>Interview of Jasper Kirkby, CLOUD experiment spokesperson<span> (Video: CERN)</span></figcaption></figure><figure class="cds-image" id="CERN-PHOTO-201909-278-1"><a href="//cds.cern.ch/images/CERN-PHOTO-201909-278-1" title="View on CDS"><img alt="Experiments and Collaborations,CLOUD,PS, cosmic rays" src="//cds.cern.ch/images/CERN-PHOTO-201909-278-1/file?size=large" /></a> <figcaption><p>CLOUD experiment <span> (Image: CERN)</span></p> </figcaption></figure></div> <div class="field field--name-field-p-news-display-news-file field--type-file field--label-hidden field--items"> <div class="field--item"><span class="file file--mime-application-pdf file--application-pdf icon-before"><span class="file-icon"><span class="icon glyphicon glyphicon-file text-primary" aria-hidden="true"></span></span><span class="file-link"><a href="https://home.cern/sites/home.web.cern.ch/files/2020-05/cloud_collaboration.pdf" type="application/pdf; length=101692" title="Open file in new window" target="_blank">cloud_collaboration.pdf</a></span></span></div> </div> Tue, 12 May 2020 16:26:34 +0000 ssanchis 154719 at https://home.cern Teresa Rodrigo Anoro (1956 – 2020) https://home.cern/news/obituary/experiments/teresa-rodrigo-anoro-1956-2020 <span>Teresa Rodrigo Anoro (1956 – 2020)</span> <span><span lang="" about="/user/151" typeof="schema:Person" property="schema:name" datatype="">anschaef</span></span> <span>Wed, 04/29/2020 - 10:19</span> <div class="field field--name-field-p-news-display-body field--type-text-long field--label-hidden field--item"><p>Teresa Rodrigo Anoro, professor of atomic and nuclear physics at the University of Cantabria, died peacefully at home on 20 April after a long illness. Teresa Rodrigo was a leading figure within the particle physics community and played a key role in shaping Spanish particle physics policies, with emphasis on promoting the participation of women in science.</p> <p>Teresa Rodrigo was born in Lleida, Spain, in 1956. After her bachelor’s degree in physics from the University of Zaragoza, she joined the High-Energy Physics group of La Junta de Energía Nuclear in Madrid (currently CIEMAT), earning a PhD in 1985 on the production of strange particles at the NA23 experiment at CERN, under the supervision of Antonio Ferrando. She moved to CERN to participate in the development of the Uranium-TMP calorimeter for the upgrade of the UA1 experiment, where she started her personal journey towards finding the top quark, which eventually brought her to the CDF experiment at Fermilab. There, she carried out the detailed modelling of the W+jet background, a crucial part of the top discovery. In 1994, she took up a faculty position at the Instituto de Física de Cantabria (IFCA) in Santander, launching a new line of research on hadronic collider physics and incorporating the IFCA group into both the CDF experiment and the newly formed CMS collaboration. Under her direction, the group continued her study of the properties of the top quark and opened up a new line of research towards the discovery of the Higgs boson. More recently, moving away from hadron beams for the first time, Teresa promoted a new line of research on the search for light dark matter particles at the DAMIC experiment. Teresa was well aware of the importance of technology development and detector building in HEP and orchestrated her group’s contribution to the construction of the CMS muon spectrometer, in particular its muon alignment system, and to the building of the ToF detector of the CDF experiment.</p> <p>Teresa’s scientific insight and strong commitment to whatever endeavour she was engaged in were well recognised by the international HEP community: she was elected chair of the CMS Collaboration Board (2011-12) and served as a member of several scientific policy committees, including the European Physics Society HEPP Board (2006-2013) and the CERN Scientific Policy Committee (2012-2017). Outside the world of academia, she was a member of several Spanish ministerial scientific panels and of the technical and research panel of the Princesa de Asturias awards. She also held an honorary doctorate from the Universidad Internacional Menéndez Pelayo and received the silver medal of the Universidad de Cantabria and the first Julio Peláez award for female pioneers in science, among other recognitions.</p> <p>Teresa’s influence on the Santander HEP group and the IFCA institute that she directed until a few months ago remains very visible. During her tenure, the group grew considerably in terms of both staff and research infrastructures, greatly expanding its activities. Under her directorship, the institute was awarded the greatest distinction of excellence of the Spanish science system, the Maria de Maeztu grant, and the gender equality prize awarded by the Spanish National Research Council (CSIC).</p> <p>Some of us, who were fortunate enough to know Teresa and to share some of her scientific passions, are aware of how kind, approachable, righteous and sympathetic she was, though with a strong personal character that came from her deep honesty, both in life and as a scientist. Teresa’s legacy stands as a testament to her leadership, her vision and her ability to mentor rising colleagues. She will be sorely missed.</p> <p>We would like to express our sympathies and heartfelt condolences to her husband Antonio and her family.</p> <p class="text-align-right"><em>Her colleagues and friends</em></p> </div> Wed, 29 Apr 2020 08:19:15 +0000 anschaef 154618 at https://home.cern Danila Tlisov (1983–2020) https://home.cern/news/obituary/experiments/danila-tlisov-1983-2020 <span>Danila Tlisov (1983–2020)</span> <span><span lang="" about="/user/146" typeof="schema:Person" property="schema:name" datatype="">cmenard</span></span> <span>Fri, 04/17/2020 - 18:19</span> <div class="field field--name-field-p-news-display-body field--type-text-long field--label-hidden field--item"><p>It is with great sadness that we inform you that Danila Tlisov, a member of the CMS collaboration at CERN, passed away on 14 April in Russia due to complications associated with COVID-19. He was 36 years old.</p> <p>Danila joined the INR Moscow group in 2010 as a young researcher after graduating with honours from Moscow State University and defending his dissertation. Following his contributions to early heavy-neutrino searches, Danila started to work on the CMS hadron calorimeter (HCAL) subsystem in 2012.</p> <p>Danila himself was the strong hub of the multinational CMS HCAL upgrade effort, leading the CERN-based team that received individual components from India, Russia, Turkey and the United States and assembled them into a working detector. Danila recently brought his unique mix of strengths to the CMS HCAL management team as Deputy Project Manager and a member of the CMS Management.</p> <p>In the physics analysis realm, Danila worked with the University of Rochester group on a measurement of the electroweak mixing angle using the forward-backward asymmetry in Drell-Yan events. Danila focused on critical improvements to the calibration of the electron-energy measurements in challenging regions of Drell-Yan kinematic phase space.<br /><br /> CMS friends and colleagues remember fondly the warm smile and incredibly effective leadership of Danila. His practical know-how and excellent judgement were critical as we worked together through the usual tough challenges of a detector upgrade.<br /><br /> Danila was an accomplished backcountry touring skier. Because of his great physical strength and focus on climbing, it was often said that he may have been faster going uphill than downhill, and that is saying a lot.<br /><br /> Among his many colleagues, Danila will be remembered for his pleasant, cheerful disposition even during times of intense pressure. He challenged us with his brilliant ideas, guided students with patience and grace and inspired us all. He will be sorely missed.</p> <p>We would like to express our sympathies and heartfelt condolences to his wife and his family in Russia.<br />  </p> <p class="text-align-right"><em>His colleagues and friends from the CMS collaboration</em></p> <div id="vidyowebrtcscreenshare_is_installed"> </div> <div id="vidyowebrtcscreenshare_is_installed"> </div> <div id="vidyowebrtcscreenshare_is_installed"> </div></div> Fri, 17 Apr 2020 16:19:23 +0000 cmenard 154545 at https://home.cern ATLAS honours its Thesis Awards Winners https://home.cern/news/news/experiments/atlas-honours-its-thesis-awards-winners <span>ATLAS honours its Thesis Awards Winners </span> <span><span lang="" about="/user/21331" typeof="schema:Person" property="schema:name" datatype="">thortala</span></span> <span>Tue, 03/10/2020 - 15:28</span> <div class="field field--name-field-p-news-display-body field--type-text-long field--label-hidden field--item"><p>On 27 February, an ATLAS team announced the winners of the 2019 Thesis Awards. The lucky few were <a href="https://cds.cern.ch/record/2696211?ln=en">Ahmed Tarek Abouelfadl Mohamed</a> (Paris-Diderot University), <a href="https://cds.cern.ch/record/2699575?ln=en">Daniel Joseph Antrim</a> (University of California, Irvine), <a href="https://cds.cern.ch/record/2684038?ln=en">Elodie Deborah Resseguie</a> (University of Pennsylvania), <a href="https://cds.cern.ch/record/2677474?ln=en">Karri Folan Di Petrillo</a> (Harvard University), <a href="https://cds.cern.ch/record/2676822?ln=en">Khilesh Pradip</a> (University of Pennsylvania) and <a href="https://cds.cern.ch/record/2697418?ln=en">Stephen Burns Menary</a> (University of Manchester).</p> <p>The excellence of the theses made the selection process difficult, as Călin Alexa, Chair of the 2019 ATLAS Thesis Awards Committee, pointed out: “We received 35 nominations this year, the highest number since 2013. We would like to congratulate all of the nominees and their supervisors for their outstanding work. It was quite challenging for us to choose the winning six.”</p> <p>Almost 1200 PhD students study in the collaboration on diverse areas of ATLAS physics, ranging from detector development to physics analysis and software studies.</p> <p>____</p> <p><em>Find out more on <a class="bulletin" href="https://atlas.cern/updates/atlas-news/thesis-awards-winners">the ATLAS website.</a></em></p> </div> Tue, 10 Mar 2020 14:28:29 +0000 thortala 153282 at https://home.cern At CMS, artificial neural networks search for exotic particles https://home.cern/news/news/experiments/cms-artificial-neural-networks-search-exotic-particles <span>At CMS, artificial neural networks search for exotic particles </span> <span><span lang="" about="/user/21331" typeof="schema:Person" property="schema:name" datatype="">thortala</span></span> <span>Fri, 03/06/2020 - 16:22</span> <div class="field field--name-field-p-news-display-body field--type-text-long field--label-hidden field--item"><p>The CMS Collaboration has developed an artificial neural network that can identify exotic particles generated by the proton–proton collisions inside the LHC.</p> <p>The “long-lived” particles chased after by the experiments can travel measurable distances (fractions of millimetres or more) from the collision point inside each LHC experiment before decaying. Most of these long-lived particles are undetectable, but could decay to detectable particles, which would lead to a rather atypical experimental signature.</p> <p>This is where CMS’s new tool comes into play. Standard algorithms used to interpret the data from proton–proton collisions are not designed to seek out such odd-looking events. Artificial neural networks, though, can automatically learn from data to achieve their goal. CMS’s neural network has been fed data from real collision events to train it to spot the odd events by itself.</p> <p>This project is part of a larger, coordinated effort across all the LHC experiments to use modern machine-learning techniques that will improve the recording and analysis of the large amounts of LHC data. It marks a new step forward after decades of artificial-intelligence use in the field of high-energy particle physics.</p> <p><em>Read the <a class="bulletin" href="https://cms.cern/news/using-artificial-intelligence-search-new-exotic-particles">full story on the CMS website</a>.</em></p> </div> Fri, 06 Mar 2020 15:22:28 +0000 thortala 153267 at https://home.cern Using LEGO to study the building blocks of the universe https://home.cern/news/news/experiments/using-lego-study-building-blocks-universe <span>Using LEGO to study the building blocks of the universe</span> <div class="field field--name-field-p-news-display-byline field--type-entity-reference field--label-hidden field--items"> <div class="field--item">Achintya Rao</div> </div> <span><span lang="" about="/user/34" typeof="schema:Person" property="schema:name" datatype="">achintya</span></span> <span>Fri, 02/07/2020 - 15:52</span> <div class="field field--name-field-p-news-display-list-cds field--type-cerncdsmedia field--label-hidden field--item"><figure class="cds-image" data-record-id="2708872" data-filename="LegoInTunnel_v2" id="CERN-HOMEWEB-PHO-2015-001-2"> <a href="//cds.cern.ch/images/CERN-HOMEWEB-PHO-2015-001-2" title="View on CDS"> <img alt="LEGO moving table for NA61/SHINE" src="//cds.cern.ch/images/CERN-HOMEWEB-PHO-2015-001-2/file?size=medium"/> </a> <figcaption> A makeshift moving table was prepared using LEGO bricks for use by the NA61/SHINE experiment <span> (Image: CERN)</span> </figcaption> </figure></div> <div class="field field--name-field-p-news-display-body field--type-text-long field--label-hidden field--item"><p>CERN’s accelerator complex helps scientists probe the fundamental building blocks of the universe. But when one scientist needed to construct a radiation-hard apparatus to test novel sensors at CERN, he turned to the building blocks of his childhood: LEGO.</p> <p><a href="/science/experiments/na61shine">NA61/SHINE</a> is a fixed-target experiment that uses particle beams from the <a href="/science/accelerators/super-proton-synchrotron">Super Proton Synchrotron</a> to study the properties of hadrons, which are composite particles made of quarks and gluons. In 2015, the NA61/SHINE team planned to build a new subsystem based on pixel sensors. These sensors are essentially modified smartphone cameras and serve as excellent hadron detectors. First, though, the scientists had to know if the sensors could withstand aggressive radioactive impacts caused by a beam of lead nuclei.</p> <p>When an unforeseen issue with the NA61/SHINE magnets prevented regular data taking for a few weeks, the collaboration decided to use the available lead-ion beam to test the sensors. The sensor samples could be acquired at short notice, but a remote-controlled, movable table to hold them in the particle beam was needed. This table had to be lightweight and resistant to nuclear activation from the radiation. Building it at the mechanical workshop would have taken more time than was available for the tests.</p> <p>One evening, while playing with his two-year-old daughter, NA61/SHINE scientist Michael Deveaux absent-mindedly puzzled over the problem. He realised that not only would LEGO provide a light and activation-resistant material, a device made with the bricks could also be engineered quickly and modified if needed. Michael called his younger brother and implored him to retrieve their childhood LEGO boxes from their parents’ home. The brother – an architect by training – teamed up with his own ten-year-old son to fetch the boxes and design a prototype movable table. Meanwhile, Michael bought missing components, like an electric motor, from a LEGO shop in Frankfurt.</p> <figure class="cds-image align-right" id="CERN-HOMEWEB-PHO-2015-001-4"><a href="//cds.cern.ch/images/CERN-HOMEWEB-PHO-2015-001-4" title="View on CDS"><img alt="home.cern,Experiments and Tracks" src="//cds.cern.ch/images/CERN-HOMEWEB-PHO-2015-001-4/file?size=large" /></a> <figcaption>A note from Michael reminds his colleagues of the serious nature of his LEGO apparatus (Image: Michael Deveaux/CERN)</figcaption></figure><p>The siblings reconvened the following weekend, tested the table and measured the speed at which it could move the sample. After all, without visual contact, one could only drive the device remotely by knowing its speed and counting the seconds. Once they were convinced it could work, Michael submitted a report to NA61/SHINE and the colourful device was installed in November 2015.</p> <p>“Soon, my colleagues started to complement the experiment by adding some LEGO trees on top of the structure,” recounts Michael. “I had to write a message asking them not to do so.”</p> <p>The tests were successful and provided the required information. And what about the improvised table? “Today,” Michael says with a grin, “the LEGO apparatus sits on a shelf in my office, awaiting use in the future, either by NA61/SHINE or my children!”</p> </div> Fri, 07 Feb 2020 14:52:51 +0000 achintya 137118 at https://home.cern A new life for AMS https://home.cern/news/news/experiments/new-life-ams <span>A new life for AMS</span> <div class="field field--name-field-p-news-display-byline field--type-entity-reference field--label-hidden field--items"> <div class="field--item">Thomas Hortala</div> </div> <span><span lang="" about="/user/21331" typeof="schema:Person" property="schema:name" datatype="">thortala</span></span> <span>Thu, 02/06/2020 - 12:20</span> <div class="field field--name-field-p-news-display-body field--type-text-long field--label-hidden field--item"><p>The voyage of ESA astronaut Luca Parmitano and his colleagues Alexander Skvortsov and Christina Koch aboard the International Space Station (ISS) <a href="https://www.esa.int/Science_Exploration/Human_and_Robotic_Exploration/Record-breaking_spacewalker_returns_from_orbit">ended this morning, as their capsule touched down just after 10 a.m. (CET) in Kazakhstan</a>. Over the course of his six months on board the ISS (including four months as its commander), Luca Parmitano and his colleague Andrew Morgan of NASA carried out <a href="https://home.cern/news/news/experiments/spacewalk-ams-watch-live-cern-and-esa">four spacewalks</a> to maintain and repair the <a href="https://home.cern/science/experiments/ams">Alpha Magnetic Spectrometer (AMS-02)</a>. Assembled at CERN by an international team of scientists, the detector was installed on the ISS in 2011 and has since collected valuable cosmic-ray data.</p> <p>The repairs carried out by Luca Parmitano and Andrew Morgan will extend the lifetime of the experiment, which is searching for dark matter and antimatter, to match that of the space station itself. In particular, during four difficult spacewalks, the two astronauts replaced the cooling system, which is essential to the operation of the cosmic-particle detector.</p> <p>Watch <a class="bulletin" href="https://www.youtube.com/watch?v=ogjUtZeoHOo&amp;feature=youtu.be">our video</a> on the spacewalk programme and the work carried out at CERN by scientists from the AMS collaboration in close contact with the astronauts. </p> <figure><iframe allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen="" frameborder="0" height="315" src="https://www.youtube-nocookie.com/embed/ogjUtZeoHOo?rel=0" width="560"></iframe> <figcaption>Video: CERN</figcaption></figure></div> Thu, 06 Feb 2020 11:20:50 +0000 thortala 134042 at https://home.cern Watch live the new spacewalk for AMS https://home.cern/news/news/experiments/watch-live-new-spacewalk-ams <span>Watch live the new spacewalk for AMS</span> <span><span lang="" about="/user/159" typeof="schema:Person" property="schema:name" datatype="">abelchio</span></span> <span>Mon, 12/02/2019 - 11:57</span> <div class="field field--name-field-p-news-display-caption field--type-string-long field--label-hidden field--item">ESA astronaut Luca Parmitano imaged during the first spacewalk for AMS hitching a ride on the International Space Station’s 16-metre long robotic arm. (Image: ESA/NASA)<br /> </div> <div class="field field--name-field-p-news-display-body field--type-text-long field--label-hidden field--item"><p>Today, European Space Agency (ESA) astronaut Luca Parmitano and NASA astronaut Andrew Morgan will begin the third of a series of complex <a href="/news/news/experiments/spacewalk-ams-watch-live-cern-and-esa">spacewalks</a> to service the <a href="/science/experiments/ams">Alpha Magnetic Spectrometer (AMS-02)</a>. The duo will install the new cooling pump system for the spectrometer’s detector tracker.</p> <p>This spacewalk is the most important for AMS scientists at the AMS Payload Operations Control Centre (POCC) at CERN. Lead AMS engineer Zhan Zhang will work in tandem with the astronauts to install and put in operation the tracker’s cooling pump system.</p> <p>CERN will go live at 14:15 CET from POCC, featuring commentary during the crucial stages of the spacewalk by AMS scientists Andrei Kounine, deputy spokesperson for AMS, Mercedes Paniccia  from the University of Geneva, and Giovanni Ambrosi from INFN Perugia.</p> <figure><iframe allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen="" frameborder="0" height="315" src="https://www.youtube-nocookie.com/embed/q1pze21El44?rel=0" width="560"></iframe> <figcaption>Video: CERN</figcaption></figure><p>Follow the live from <a href="https://twitter.com/CERN">@CERN</a> on Facebook and YouTube and ask your questions using the hashtag <a href="https://twitter.com/hashtag/SpacewalkForAMS">#SpacewalkForAMS</a>.</p> </div> Mon, 02 Dec 2019 10:57:38 +0000 abelchio 14254 at https://home.cern AWAKE: More plasma = more acceleration https://home.cern/news/news/experiments/awake-more-plasma-more-acceleration <span>AWAKE: More plasma = more acceleration</span> <div class="field field--name-field-p-news-display-byline field--type-entity-reference field--label-hidden field--items"> <div class="field--item">Anaïs Schaeffer</div> </div> <span><span lang="" about="/user/151" typeof="schema:Person" property="schema:name" datatype="">anschaef</span></span> <span>Tue, 11/26/2019 - 12:28</span> <div class="field field--name-field-p-news-display-body field--type-text-long field--label-hidden field--item"><p>In May 2018, the <a href="http://awake.web.cern.ch/awake/">AWAKE</a> experiment carried out the <a href="https://home.cern/news/news/experiments/success-awake">first ever acceleration of electrons</a> using a wakefield created by protons flowing through plasma. AWAKE demonstrated that it is not only possible but also efficient to use plasma wakefields generated by proton beams to accelerate charged particles, thereby fulfilling the objective of the AWAKE Run 1 phase. The experiment was carried out over a distance of 10 metres, with a rubidium plasma cell.</p> <p>The next phase, AWAKE Run 2, will start after the LS2 and involves maintaining the quality of an electron beam when it is accelerated and demonstrating the feasibility of the technology over several hundred metres. “The AWAKE plasma is currently produced by sending a laser pulse which transforms rubidium gas into plasma by ionisation. This works well as the AWAKE cell is 10 metres long, but this ionisation method is not appropriate for a larger scale”, explains Alban Sublet, an applied physicist in the Vacuum, Surfaces and Coatings group within the Technology Department.</p> <p>This is where the helicon plasma cell comes in. A helicon wave is a low frequency electromagnetic wave capable of generating very high-density plasmas, like those needed for AWAKE. “We are currently working with a 1-metre prototype helicon plasma cell developed by the <a href="https://www.ipp.mpg.de/17313/greifswald">Institute for Plasma Physics </a>in Greifswald (Germany). In this set-up, helicon waves are generated by radiofrequency antennas, which surround a quartz tube filled with argon at low pressure”, explains Alban Sublet. In theory, this set-up should enable very long cells to be created as the tube can be extended and antennas added to spread the plasma over long distances.</p> <p>Ensuring that the generated plasma remains homogeneous throughout the cell remains a challenge. How can we be sure that the density required for AWAKE is uniformly reached throughout the cell? “For the time being we only have a diagnostic tool that enables us to measure the density profile of the plasma locally”, points out Alban Sublet. “So far, we have deduced the density of the rubidium plasma cell indirectly by measuring the density of the rubidium gas before it is ionised”, adds Edda Gschwendtner, technical coordinator and leader of the AWAKE project at CERN.</p> <p>To resolve this problem, the team responsible for the tests is currently working in collaboration with the <a href="https://3dpsi.engr.wisc.edu/">University of Wisconsin</a> (UW), Madison (United States) and the <a href=" https://www.epfl.ch/research/domains/swiss-plasma-center/">Swiss Plasma Center (SPC)</a> at the EPFL in Lausanne. Two plasma diagnostic techniques are currently being studied and will be tested at CERN in 2020. “Developing a diagnostic tool capable of measuring the uniformity of the plasma with the precision required by AWAKE throughout the length of the cell is a significant challenge”, explains Alban Sublet. “Once we have developed a reliable diagnostic method, we will be able to optimise the helicon plasma cell and then design a longer helicon cell for use in AWAKE in a few years.” Synergies exist with the field of coatings and surface treatments, where this type of plasma might be used in the future, as is the case for certain industrial applications.</p> </div> Tue, 26 Nov 2019 11:28:17 +0000 anschaef 14226 at https://home.cern Spacewalk for AMS: Watch live with CERN and ESA https://home.cern/news/news/experiments/spacewalk-ams-watch-live-cern-and-esa <span>Spacewalk for AMS: Watch live with CERN and ESA</span> <span><span lang="" about="/user/40" typeof="schema:Person" property="schema:name" datatype="">katebrad</span></span> <span>Thu, 11/14/2019 - 12:33</span> <div class="field field--name-field-p-news-display-body field--type-text-long field--label-hidden field--item"><p>On Friday 15 November, European Space Agency (ESA) astronaut Luca Parmitano and NASA astronaut Andrew Morgan will begin the first of a series of complex spacewalks to service the <a href="/science/experiments/ams">Alpha Magnetic Spectrometer (AMS-02)</a>. The spacewalk will be streamed live via <a href="http://www.esa.int/ESA_Multimedia/ESA_Web_TV">ESA Web TV</a> from 12.50 p.m. CET and will include commentaries from CERN and ESA.</p> <p>This series of spacewalks is expected to be the most challenging since those to repair the <a href="https://www.nasa.gov/mission_pages/hubble/servicing/index.html">Hubble Space Telescope</a>. AMS was originally intended to run for three years, after its installation on the International Space Station in 2011, and was not designed to be maintained in orbit. However, the success of its results to date have meant that its mission has been extended.</p> <figure><iframe allowfullscreen="" frameborder="0" height="360" id="ls_embed_1573808401" scrolling="no" src="https://livestream.com/accounts/362/events/8890996/player?width=640&amp;height=360&amp;enableInfoAndActivity=true&amp;defaultDrawer=&amp;autoPlay=true&amp;mute=false" width="640"></iframe> <figcaption>Watch the spacewalk live on <a href="https://livestream.com/ESA/SpacewalkforAMS">ESA Web TV</a></figcaption></figure><p>AMS-02 is a particle-physics detector that uses the unique environment of space to study the universe and its origin. It searches for antimatter and dark matter while precisely measuring cosmic-ray particles – more than 140 billion particles to date. The detector, which measures 60 cubic metres and weighs 7.5 tonnes, was assembled by an international team at CERN, and researchers, astronauts and operations teams have had to develop new procedures and more than 20 custom tools to extend the instrument’s life.</p> <p>A key task for the astronauts is to replace the AMS-02 cooling system and to fix a coolant leak, and the pair have trained extensively for this intricate operation on the ground. It will involve cutting and splicing eight cooling tubes, connecting them to the new system and reconnecting a myriad of power and data cables. It is the first time that astronauts will cut and reconnect cooling lines in orbit.</p> <p>The first AMS spacewalk on Friday is expected to last about six hours and sets the scene for at least three more. It will be streamed live on <a href="http://www.esa.int/ESA_Multimedia/ESA_Web_TV">ESA Web TV</a> and the first two hours will feature commentary from scientists at the AMS Payload Operations Control Centre (POCC) at CERN as well as astronaut and operation experts at ESA’s astronaut centre in Germany.</p> <p>CERN’s contributions will include a tour of the POCC by AMS Experiment and Operations Coordinator Mike Capell, from Massachusetts Institute of Technology (MIT). Here, AMS physicists take 24-hour shifts to operate and control the various components of AMS from the ground. Zhan Zhang, also from MIT, is the lead engineer of the Upgraded Tracker Thermal System, which is being installed during the spacewalks. She will show the laboratory at CERN where an identical spare of the system is kept in space conditions and will explain how the system works and what the astronauts will have to do to install it on the AMS detector in space. AMS scientists Mercedes Paniccia from the University of Geneva, Alberto Oliva from INFN Bologna and Andrei Kounine, from MIT, will explain the science of AMS as the spacewalk takes place and can answer your questions.</p> <p>You can already tweet questions ahead of the live broadcast to <a href="https://twitter.com/esaspaceflight">@esaspaceflight</a> or <a href="https://twitter.com/CERN">@CERN</a> using the hashtag <a href="https://twitter.com/hashtag/SpacewalkForAMS">#SpacewalkForAMS</a>.</p> </div> Thu, 14 Nov 2019 11:33:55 +0000 katebrad 14105 at https://home.cern