Jobs – Page 214 of 521

Massimo Tarenghi: a lifetime in the stars

Massimo Tarenghi – builder of the world’s biggest telescope and an accomplished photographer.
Image credit: M Struik.

Massimo Tarenghi fell in love with astronomy at age 14, when his mother took away his stamp collection – on which he spent more time than on his schoolbooks – and gave him a book entitled Le Stelle (The Stars). By age 17, he had built his first telescope and become a well-known amateur astronomer, meriting a photo in the local daily newspaper with the headline “Massimo prefers a bigger telescope to a Ferrari.” Already, his dream was “to work at the largest observatory in the world”. That dream came true, because Massimo went on to build and direct the world’s most powerful optical telescope, the Very Large Telescope (VLT), at the European Southern Observatory (ESO)’s Paranal Observatory in Chile.

“I was born as a guy who likes to do impossible things and I like to do them 110%,” says Massimo, who decided to study physics at the University of Milan in the late 1960s “because [Giusepppe] Occhialini was the best in the world and allowed me to do a thesis in astronomy”. His road to the stars began in 1970, when he gained his PhD with a thesis on the production of gamma rays by Sagittarius A – at the time a mysterious radio source, which is now known to harbour the supermassive black hole at the centre of the Milky Way. This was at the time of the first observations in X rays and in infrared of the centre of the Galaxy, and the first of many examples of far-sighted intuition in Massimo’s career.

Following his PhD, Massimo convinced his colleagues at Milan to support the construction of an infrared telescope on the Gornergrat in the Swiss Alps. He was then sent to the Steward Observatory at the University of Arizona, where he did pioneering work in infrared astronomy. He quickly made himself known with a daring request for telescope time involving all of the instruments. “At that time,” he recalls, “there was a clear separation between astronomy for infrared, spectroscopy or photography, and there were three levels of use of an instrument: astronomer without assistant, assistant astronomer, or general (university) public. I asked for all of the instruments – and in particular for the bolometer, which no one had ever dared ask for!” After a three-hour meeting, his proposal to observe infrared galaxies was judged “very interesting but totally crazy”. So the committee suggested a compromise: 10 of his candidate objects would be observed during the telescope’s spare time and then they could review the request. Massimo accepted, and two weeks later seven of his objects had been found to be infrared emitters. “So they gave me the whole bolometer three-months later. I was lucky!” he says with the same enthusiasm as the 28-year-old postdoc he was at the time.

It was, once again, pure intuition. Massimo had chosen his 10 objects based on M82, a galaxy that interacts with its larger neighbour M81. “M82 is a beautiful galaxy with explosions and I thought, when two galaxies interact, they trigger explosions. So I simply had a collection of interacting galaxies and it came out that this is just what they did.” This intuition was to be confirmed by what has become a pillar of astrophysics: when two galaxies interact, the gas inside is compressed, creating a large number of new stars, which produce a large amount of infrared emission as they form.

The award-winning futuristic Residencia for astronomers at Paranal, conceived by Massimo.
Image credit: ESO/M Tarenghi.

While still in Arizona, Massimo decided to work on the optical identification of radio galaxies. “At the time, the Hercules cluster was not very well explored, with a redshift of 11,000 km/s. Compared to the well-known Coma cluster, with a redshift of 5000 km/s, it is much further and very difficult to observe between Arizona’s summer storms,” he explains. “Astronomers came to me saying that the cluster was ‘theirs’, as they had started work on it three years earlier. But they had done no observations. So I offered to collaborate, and we decided that whoever took more galaxies would be the first author on the publication. They found 19, I took all of the rest: 300.” That paper is now a cornerstone in astronomy. “It was the first time we saw clearly the existence of a void in the universe,” he continues. “There was no galaxy between 6000 and 9000 km/s. Today we know this void is the remnant of the Big Bang, the structure of the anisotropy of the universe recently observed by the Planck space telescope.”

Breaking records

Dubbing himself “a difficult person,” Massimo broke new ground not just in the way that astronomy is done, but by bringing innovation in the way that telescopes are conceived of and built. Intuition, determination and audacity are indeed the distinctive marks of his 35-year-long career at ESO, which he joined in 1977 as a member of the Science Group, when the organization was still based at CERN (CERN Courier October 2012 p26). He had decided to join ESO to observe with the largest European telescope – the 3.6 m, which was just being inaugurated at ESO’s site at La Silla in Chile.

“I obtained three nights for my cluster of galaxies in the Southern hemisphere,” he recalls, “but I was the second official user, during the first week of observation, and nobody knew if it was going to work. I received those three nights (plus three to compensate in case of problems) because I was the only one in Europe who had experience with big telescopes. I started to complain the first night and obtained the sixth night.” Massimo was then told that there would be another week of tests and he was asked if he would test the telescope, so he took the full week. “My colleagues were jealous but then were surprised that I really tested the telescope to adjust and calibrate it.” After these two weeks, he went back to Geneva and told ESO’s director that astronomers need to be associated with the construction of telescopes from the start. “So I created the role of ‘friend of instrument’ and for each instrument we associated one astronomer in charge,” he explains. The role of instrument scientist, commonplace now at the large telescopes worldwide, is thus Massimo’s invention.

Unsurprisingly, he then became project scientist for ESO’s next telescope, the 2.2 m. Built for the Max Planck Institute, it had been destined for Namibia originally, but with Italy and Switzerland about to join ESO in 1981, the decision was taken to install it at ESO’s site at La Silla. “The Italians are very aggressive astronomers,” Massimo explains, “so we needed to increase telescope time, and I was asked to take the 2.2 m telescope from Heidelberg, put it in place in La Silla, and run the team.” They had to do everything: they had no dome, no foundations, and a budget of only DM 5 million, which was a very limited amount compared with other projects of a similar size. But, as Massimo says, “when you have no money you do great things,” and he had an idea. “I saw a thin aluminium dome on the last page of an amateur astronomers’ magazine, and I asked an engineer in my team to design a scaled-down version of our dome.” With the concrete foundations laid almost manually, and the help of three engineers recruited from Zeiss to build a new electronic system, they succeeded in installing the telescope for a total cost of DM 7 million.

The 2.2 m telescope saw its first light in June 1983, with a record-breaking angular resolution of 0.6 arc seconds. “The reason is simple,” says Massimo. “The dome was so small that we had to move all the electronics underneath, so there was no source of heat coming from the telescope, and that’s how we learnt how to remove heat from the dome.” It was also the first telescope to be operated remotely. “We took the controls from the upper floor to the lower floor, and when we saw that it worked, with the software engineer we decided to do remote control from La Serena. Everybody was laughing, saying it would never work, but there was no reason it should not!” At the time, the connection was through a telephone line – not with optical fibre – and only in one direction. Massimo explains that when they needed somebody to close the dome on the other side, they used the phone to communicate from La Serena to La Silla. On the first occasion, he recalls, “I forgot the guy was still there. All night he was waiting for my call, and he waited five, six hours before he decided to call me, asking whether he could…go to the toilet!”

In 1983, Massimo was asked to be project manager for the New Technology Telescope (NTT), a 3.6 m optical telescope that saw first light six years later. With a record-breaking resolution of 0.33 arc seconds, it produced sharper images of stellar objects than ever obtained with a ground-based telescope. The NTT was the prototype for a new type of telescope that would make the VLT possible. The main revolutionary feature was the application of active optics, in which a thin and flexible primary mirror is kept in its correct shape by a support system that responds to continual real-time analysis of a stellar image. It was ESO’s Ray Wilson who invented the system, but Massimo was involved from early on, and his former institute in Milan built the first test bench with which the system was shown to work in the early 1980s. The thin-mirror technology allowed by active optics was the breakthrough that enabled the construction of the next generation of much larger telescopes, in particular the VLT, built on a second ESO site in Chile, on the mountain of Cerro Paranal in the Atacama desert.

The VLT was proposed in 1986 and approved in 1987. Massimo was given the responsibility to build it in March 1988 by ESO’s director-general Herry van der Laan, and was later fully supported by the following director-general, Riccardo Giacconi. He was part of the team that decided to go from 4 m to 8 m mirrors that could be combined as an astronomical interferometer – a technique that was still in its early days. With four fixed 8.2 m-diameter Unit Telescopes (UTs) and four 1.8 m-diameter movable Auxiliary Telescopes (ATs), the VLT is today the most advanced optical observatory in the world. The UTs work either individually or in a combined mode using interferometry, while the ATs are entirely dedicated to interferometry. “I had under me 250 technicians. It was the craziest project I ever managed,” Massimo remembers, “and I learnt a lesson: if you want to work in the biggest observatory in the world you have to build it!”

Building the Paranal Observatory was not just a scientific experience for Massimo, he is at also at the origin of the award-winning futuristic Residencia, chosen as the set for the James Bond film Quantum of Solace. “I wanted something that could make astronomers at Paranal become human again after 13 or 14 hours of observation, to experience the pleasure of water, and of green, red and all the colours missing in the desert,” he explains. “This is the dream we recreated in this place, water in the desert, for the people working at the most advanced telescope in the world.”

After the VLT, Massimo went on to direct another “crazy” astronomy project, the Atacama Large Millimeter/submillimeter Array (ALMA), the first truly global collaboration in astronomy (CERN Courier October 2007 p23). He also conducted the exploration work for the site of the next-generation facility, the European Extremely Large Telescope (E-ELT), with a record-breaking 39 m-diameter mirror. Construction work started at the Cerro Armazones, the chosen site for E-ELT, in March 2014. Massimo, who celebrated his 70th birthday at the end of July, officially retired from ESO in 2013, but he has not stopped working for European astronomy. He still commutes between the ESO sites in Chile, Santiago and Munich, supporting ESO’s public-relations activities in Chile – and spending endless nights photographing the unique sky above the Atacama desert.

The Beauty of Physics: Patterns, Principles, and Perspectives

By A R P Rau
Oxford University Press
Hardback: £25
Also available as an e-book

The selection of topics in this book reflects the author’s four-decade career in research physics and his resultant perspective on the subject. While aimed primarily at physicists, including junior students, it also addresses other readers who are willing to think with symbols and simple algebra in understanding the physical world. Each chapter, on themes such as dimensions, transformations, symmetries, or maps, begins with simple examples accessible to all, while connecting them later to more sophisticated realizations in more advanced topics of physics.

Crackle and Fizz: Essential Communication and Pitching Skills for Scientists

By Caroline van den Brul
Imperial College Press
Hardback: £35
Paperback: £15
E-book: £11

The introduction of Crackle and Fizz sets out a trope that may sound familiar: a decade-old social faux pas between scientists and journalists at a dinner party, where the speed-dating format for presenting science was met with ire, derision and altogether not having a nice time. The claim is made that this could have been a chance to start over, to reframe science communication and realign the expectations of those involved. To do so misses out on the past few decades of development in the science-communication field, which is now reaching a reflective maturity and presence between academia, industry and media. Unfortunately, the same erasure is a leitmotif in many of the chapters that follow.

Caroline van den Brul’s credentials are impressive, with years at the helm of BBC productions and engagement workshops. This history forms the backbone of the book, setting an anecdote-per-chapter rate that reads more like an autobiography than an attempt to impart any lessons or experience to the reader. The remaining space is given over to consideration of narrative devices useful in contextualizing topics and engagement from a practitioner’s perspective. However, these are only superficially explored and offer little in variation. After many pages promoting the importance of clarity, the titular “Crackle” is eventually revealed in the final chapter to be a (somewhat forced) acronym that summarizes and distils all preceding guidance. Had this been the starting point from which each aspect was explored in depth, the tone and flow of the book may have made for a more compelling read. When used as the conclusion, it feels condescendingly simplified. It’s a shame that, considering van den Brul’s history, the final chapter is the main one worth reading.

Overall, the book feels less like the anticipated dive into years of experience, and more like a pre-lunch conference workshop. If you are in the first stages of incorporating engagement and communication into your current practice, working through each chapter’s closing questions could be of some use. Or, should you feel like refreshing your current framework, they might give you a moment’s pause and adjustment, but no more than any other evaluation.

A Chorus of Bells and Other Scientific Inquiries

By Jeremy Bernstein
World Scientific
Hardback: £25
E-book: £19

In this volume of essays, written across a decade, Bernstein covers a breadth of subject matter. The first part, on the foundations of quantum theory, reflects the author’s conversations with the late John Bell, who persuaded him that there is still no satisfactory interpretation of the theory. The second part deals with nuclear weapons, and includes an essay on the creation of the modern gas centrifuge by German prisoners of war in the Soviet Union. Two shorter sections follow: the first on financial engineering, with a profile of Louis Bachelier, the French mathematician who created the subject at the beginning of the 20th century; the second and final part is on the Higgs boson, and how it is used for generating mass.

To Explain the World: The Discovery of Modern Science

By Steven Weinberg
Harper Collins/Allen Lane
Hardback: £20 $28.99
Also available at the CERN bookshop

Steven Weinberg’s most recent effort is neither a treatise on the history of science nor a philosophical essay. The author presents instead his own panoramic view of the meandering roads leading to the Newtonian synthesis between terrestrial and celestial physics, rightfully considered as the beginning of a qualitatively new era in the development of basic science.

The first and second parts of the book deal, respectively, with Greek physics and astronomy. The remaining two parts are dedicated to the Middle Ages and to the scientific revolution of Copernicus, Galileo and Newton. The aim is to distil those elements that are germane to the development of modern science. The style is more persuasive than assertive: excerpts of philosophers, poets and historians are abundantly quoted and reproduced, with the aim of corroborating the specific viewpoints conveyed in the text. A similar strategy is employed when dealing with the scientific concepts involved in the discussion. More than a third of the 416 pages of the book contain a series of 35 “technical notes” – a quick reminder of a variety of geometric, physical and astronomical themes (the Thales theorem, the careful explanation of epicycles for inner and outer planets, the theory of rainbows and various other topics relevant to the main discussion of the text).

Passing before you through the pages, you will see not only Plato and Aristotle, but also Omar Khayyam, Albertus Magnus, Robert Grosseteste and many other progenitors of modern scientists. Nearly 2000 years separate the natural philosophy of the “Timaeus” from the birth of the scientific method. Many elements contributed serendipitously to the evolution leading from Plato to Galileo and Newton: the development of algebra and geometry, the divorce between science and religion, and an improved attitude of abstract thinkers towards technology. All of these aspects have certainly been important for the tortuous emergence of modern science. But are they sufficient to explain it? Scientists, historians and laymen will be able to draw their own lessons from the past as presented here, and this is just one of the intriguing aspects of this interdisciplinary book.

After reading this book quietly, you might be led to conclude that good scientific ideas and daring conjectures take a long time to mature. It has been an essential feature of scientific progress to understand which problems are ripe to study and which are not. No one could have made progress in understanding the nature of the electron, before the advent of quantum mechanics. The plans for tomorrow require not only boldness and fantasy, but also a certain realism that can be trained by looking at the lessons of the past. Today’s most interesting questions may not be scientifically answerable tomorrow, and lasting progress does not come by looking along a single line of sight, but all around, where there are mature phenomena to be scrutinized. This seems to be true for science as a whole, and in particular for physics.

•

The Oskar Klein Memorial Lectures 1988–1999

By Gösta Ekspong (ed.)
World Scientific
Hardback: £45
E-book: £34

Perhaps every reader of CERN Courier has heard about the Klein–Gordon equation, the Klein–Nishina (Compton effect) cross-section, the Klein paradox and the Kaluza–Klein compactified five-dimensional unified theory of gravity, electricity and magnetism. However, few will know about the scientist, Oskar Klein (1894–1977), the pre-eminent and visionary Swedish theoretical physicist from Stockholm whose work continues to influence us to this day.

This book is needed. The reason is described eloquently in the contribution by Alan Guth, whose words I paraphrase: how many recognize Oskar as the first name of “this” Klein? Compare here (by birth year, within 10 years): Niels B (1885), Hermann W (1885), Erwin S (1887), Satyendra N B (1894), Wolfgang P (1900), Enrico F (1901), Werner H (1901), Paul A M D (1902), Eugene W (1902), Robert O (1904). Thanks to this book, Oskar K (1894) will take his place on this short list.

Part of the book collects together all of the Oskar Klein Memorial Lectures given since the series began at Stockholm University in 1988, through to 1999, by many well-known theoreticians, from Chen Ning Yang to Gerard ’t Hooft. Some of these lectures relate to Klein because he often happened to “be there” at the beginning of a new field in physics. For example, in early 1948, Klein recognized immediately, following the disambiguation of the pion and muon, that muon decay and common beta decay can be described by the same four-fermion interaction (see the contribution by T D Lee).

The other part of the book – a third of the 450 pages – is a biographical collection about Klein and his pivotal scientific articles (about a fifth of the volume), all presented in English, although Klein published in Danish, French, English, German and Swedish, as a check of the titles in his publication list reveals. Having Klein’s important work all in one place can lead to interesting insights: for me, finding that 24 December 1928 was a special birthday.

On this day, just eight weeks after the Klein–Nishina paper on the interaction of radiation with electrons, the paper on the Klein paradox reached the editors of Zeitschrift für Physics. Klein concludes: “…(the) difficulty of the relativistic quantum mechanics emphasized by Dirac can appear already in purely mechanical problems where no radiation processes are involved.” The yet-to-be-recognized and discovered antiparticle – the positron – was the “difficulty”, allowing for both radiative and field-instigated pair production (the “paradox”), when vacuum instability is inherent in a prescribed external field configuration.

The Klein-paradox result resurfaced soon in the work by Werner Heisenberg and Hans Euler, and Julian Schwinger on the vacuum properties of QED. Today, as we head towards the centenary of the Klein paradox, pair production in strong fields is being addressed as a priority within the large community interested in ultra-intense laser pulses.

Oskar Klein was always a colleague I wished I could meet, and finally, I have. Thank you, Gösta Ekspong, for this introduction to my new-found hero. While at first my profound personal interest in this book arose from curiosity originating from many years of working out the consequences of the Klein paradox in heavy-ion collisions, I now see how Klein can serve as a role model. This is the book to own for anyone interested in seeing further by “standing on the shoulders of giants”.

LHCf makes the most of a special run

Run 2 of the LHC may only just have officially begun, but the Large Hadron Collider forward (LHCf) experiment has already completed its data taking with proton–proton collisions at the new high energy of 13 TeV in the centre of mass. The experiment collected data in a special physics run carried out on 8–12 June, just after the start of Run 2.

The motivation of LHCf is to understand the hadronic interactions taking place when high-energy cosmic rays collide with the Earth’s atmosphere, producing bunches of particles known as air showers. These air showers allow the observation of primary cosmic rays with energies from 10¹⁵ eV to beyond 10²⁰ eV. Because a collision energy of 13 TeV corresponds to the interaction of a proton with an energy of 9 × 10¹⁶ eV hitting the atmosphere, the LHC enables an excellent test of what happens at the energy of the observed air showers.

In the LHCf control room during the special physics run.
Image credit: LHCf Collaboration.

The interaction relevant to air-shower development has a large cross-section, with most of the energy going into producing particles that are emitted in the very forward direction – that is, at very small angles to the direction of the incident particle. LHCf therefore uses two detectors, Arm 1 and Arm 2, installed at 140 m on either side of the interaction point in the ATLAS experiment (CERN Courier January/February 2015 p6).

For LHCf to be able to determine the production angle of individual particles, the experiment requires beams that are more parallel than in the usual LHC collisions. In addition, the probability for more than one collision in a single bunch crossing (pile-up) must be far smaller than unity, to avoid contamination from multiple interaction events. To meet these constraints, for the special run the beams were “unsqueezed” instead of being “squeezed”, making them larger at the collision points. This involved adjusting magnets on either side of the interaction point to increase β* – the parameter that characterizes the machine optics for the squeeze – to a value of 19 m. In addition, the collisions took place either with low beam intensities or with beams offset to each other to reduce pile-up.

Invariant-mass distribution of photon-pair events (preliminary). The two clear peaks at 135 MeV and 548 MeV correspond to the π⁰ and η, respectively.

The first collisions for physics (“stable beams”) were provided at midnight on 10 June with very low pile-up, followed until noon on 13 June by a total of six machine fills providing various pile-up values ranging from 0.003 to 0.05. This allowed LHCf to take more than 32 hours of physics data, as scheduled.

Even with a luminosity of 10²⁹ cm^–2 s^–1 – five orders of magnitude below the nominal LHC luminosity – the LHCf detectors achieved a useful data rate of > 500 Hz, recording about 15% of inelastic interactions with neutral particles of energies > 100 GeV. A preliminary analysis during the run showed the clear detection not only of π⁰ mesons but also of η mesons, which had not been the case with the data at the collision energy of 7 TeV in Run 1.

A highlight of the operation was collaboration with the ATLAS experiment. During the special run, trigger signals in LHCf were sent to ATLAS, which recorded data accordingly. The analyses of such common events will enable the classification of events based on the nature of processes such as diffractive dissociation and non-diffractive interactions.

The LHCf detectors were removed from the LHC tunnel on 15 June during the first technical stop of the LHC, to avoid the radiation damage that would occur with the increasingly high luminosity for Run 2.

Stable beams at 13 TeV

At 10.40 a.m. on 3 June, the LHC operators declared “stable beams”, signalling the official start of Run 2, see “Stable beams at 13 TeV”. The LHC experiments are now ready to take data at the unprecedented collision energy of 13 TeV and, as this page shows, LHCf has already collected all of the data it requires.

Fifth event signals discovery of ν_τ appearance

OPERA – the Oscillation Project with Emulsion-tRacking Apparatus experiment at the INFN Gran Sasso Laboratory – has detected the fifth occurrence of a tau neutrino (ν_τ). Setting out from CERN as a muon neutrino (ν_μ), the particle was detected at Gran Sasso as a ν_τ after travelling 730 km through the Earth. This detection of a fifth ν_τ firmly establishes the direct observation of the transition from ν_μ to ν_τ, with a statistical precision of 5σ, the now standard threshold for a discovery in particle physics.

The international OPERA experiment, which involves about 140 physicists from 26 research institutes in 11 countries, was designed to observe this exceptionally rare phenomenon, gathering data in the neutrino beam produced by the CERN Neutrinos to Gran Sasso (CNGS) project (CERN Courier November 2006 p24). A small fraction of the incoming neutrinos interacted with the giant detector, consisting of more than 4000 tonnes of material, with a volume of some 2000 m³ and some nine million photographic plates, to produce the particles observed. After detecting the first few ν_μ produced at CERN in 2006, the experiment has collected data for five years, from 2008 to the end of 2012. The first ν_τ was observed in 2010. The second and third events were reported in 2012 and 2013, respectively, while the fourth one was announced in 2014 (CERN Courier May 2014 p9).

The OPERA collaboration will continue to analyse the data collected, searching for other ν_μ to ν_τ transitions, and possibly also measure the oscillation parameters, for the first time using oscillated ν_τ.

HL-LHC begins the move from paper to hardware

The coil of the sextupole corrector.
Image credit: G Volpini/LASA.

The design study for the High-Luminosity LHC (HL-LHC) project is now approaching completion. The conceptual design is completed for most of the magnets, engineering is in progress, and the first hardware that will be used in the prototypes is being manufactured and tested. Recent months have seen successful tests of some of the magnets that will be essential for this high-luminosity upgrade (CERN Courier March 2015 p28).

The interaction regions of the HL-LHC will contain nine different types of new magnets, relying on three different technologies – Nb₃Sn and Nb-Ti superconductors in the form of Rutherford cable, and super-ferric magnets with Nb-Ti coils. These magnets are in the design and prototyping phase, being developed internationally by the US LHC Accelerator Research Program (US-LARP), the CIEMAT Research Centre in Spain, CEA Saclay in France, the INFN-Milano LASA laboratories and INFN-Genova in Italy, and KEK in Japan.

The mirror quadrupole entering the test station at Fermilab.
Image credit: G Chlachidze/US-LARP.

In April, the winding and impregnation of the first coil of the superferric sextupole corrector was completed and successfully tested as a stand-alone coil in the INFN-LASA laboratories. The coil had a first quench at 80% of the short-sample limit – the maximum field achievable in the magnet – and reached 91% after three quenches at 2.5 K. In these correctors, the operational current is set at 60% of short-sample limit. This was the first test of a component of the HL-LHC interaction-region magnets, with an operational peak field in the coil of 2.3 T.

In May, the first coil for the Nb₃Sn short quadrupole model, manufactured by the US-LARP collaboration, was tested in a mirror configuration at Fermilab. The coil had a first quench at 70% of the short-sample limit, a second one at 76%, and reached 90% after 20 quenches. The triplet will operate at 75%, with a peak field of 11.5 T – a value that has been recently reduced from the original 80% to add some margin, following the advice of a review committee held at CERN in December.

Since the beginning of the year, coil-winding tests have been under way, both at KEK, for the 5.6-T Nb-Ti separation dipole (D1), and at Saclay, for the 115-T/m-gradient Nb-Ti quadrupole. An iteration of the design of the iron yoke was performed at KEK to guarantee a better alignment of the dipole field during assembly. At Saclay, the first tests have confirmed the correct geometry of the end spacers and of the coil components.

The next step is testing of the first Nb₃Sn quadrupole short model this coming autumn. This is made up of two CERN coils, which have recently been shipped to the US, and two LARP coils. A test of the first corrector sextupole is foreseen in LASA at the end of the year, and a test of the first short model of the separation dipole will be carried out at KEK.

• Based on an article in acceleratingnews.web.cern.ch.

Topics

Reset your password

Registration complete

Breaking records