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Archive for August, 2013

Les 28 et 29 septembre de 9h00 à 20h00, le CERN ouvrira encore une fois ses portes au grand public. Ce sera l’occasion de visiter des dizaines de montages expérimentaux et de découvrir le plus grand laboratoire de physique des particules au monde. Tout cela gratuitement.

PO-3Des visiteurs découvrent le détecteur CMS durant les journées Portes Ouvertes en 2008

Il sera possible de descendre dans les installations souterraines et de voir les détecteurs opérant au Grand collisionneur de hadrons (LHC) : ATLAS et CMS où le boson de Higgs a été découvert, ALICE où nous explorons ce qui s’est produit un instant après le Big Bang et LHCb où le Modèle standard est affiné avec une précision inégalée. Les visiteurs auront également l’occasion de découvrir plusieurs autres expériences où nous sondons le monde de l’antimatière (AD), le mystère de la matière sombre (AMS) et l’intérieur des protons (COMPASS) pour n’en citer que quelques-unes.

PO-2Les démonstrations du groupe de cryogénie fascinent tout le monde

Pratiquement tous les aspects du laboratoire seront ouverts aux visiteurs, du centre de calcul aux ateliers mécaniques, en passant par la cryogénie et la métrologie, sans oublier les accélérateurs.

Il y aura des activités pour les enfants, des conférences d’introduction pour les plus curieux et curieuses et du plaisir garanti pour tout le monde. Vous n’aurez que l’embarras du choix. On vous promet une journée inoubliable.

Le programme est déjà en ligne. Comme les visites souterraines sont réservées aux personnes de 12 ans et plus, et soumises à des quotas stricts. Vous devez donc réserver vos places à l’avance. Les billets (gratuits) seront disponibles vers le 15 août, alors gardez l’oeil  (je serai en vacances et ne pourrai vous le rappeler). Cela garantira que tout le monde passera son temps à s’amuser plutôt qu’à faire la file.

J’espère que vous serez parmi les 100 000 personnes que nous aurons le plaisir d’accueillir.

PO-4Le nombre de visiteurs admis dans les ouvrages souterrains est limité par la capacité des ascenseurs

Pauline Gagnon

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Our Universe is Yours

Friday, August 9th, 2013

September 28 and 29, from 9:00 to 20:00, CERN is going to open its doors to the public once again. This is a not-to-be-missed opportunity to visit dozens of experimental setups and get to see what is happening in the world’s largest particle physics laboratory. All of that free of charge.

PO-3A group of visitors discovering the CMS detector during the Open Days in 2008

There will be unique opportunities to go underground and see the detectors operating at the Large Hadron Collider (LHC) where the Higgs boson was discovered (ATLAS and CMS), where we explore what happened an instant after the Big Bang (ALICE) and where the Standard Model is being refined with unprecedented precision (LHCb). Visitors will also have the opportunity to discover several other experiments where we probe the world of antimatter (AD), the puzzling mystery of dark matter (AMS) or look inside protons (COMPASS) to name but a few of them.

Just about every aspect of the laboratory will be open to the visitors, from the computing centre to the workshops, the cryogenics and metrology laboratories and the accelerators.

PO-2The cryogenic demonstrations fascinate everyone

There will be hands-on setups for kids, introductory lectures for the most inquisitive ones and fun for everyone.  Take your pick. This will be a day to remember.

The programme is already online. The underground visits are reserved to people 12 years and older and subject to strict quotas. So you will need to reserve in advance. Free tickets will be available around August 15 so keep an eye for it (I will be on vacation and unable to remind you). This will guarantee that every one spends their time playing and not queuing.

I hope many of you will be among the 100 000 people we will have the pleasure to welcome.

PO-4Taking a maximum of people down underground. The quotas are determined by the elevators capacity

Pauline Gagnon

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This article was also published on CERN’s website on 8.8.13.

Join the dots to measure antimatter.

3D model of particle tracks.

Does antimatter fall up or down?

The AEgIS experiment at CERN needs your help to analyse experimental results to figure out how antimatter is affected by gravity. Just join the dots to reconstruct particle tracks and your contribution could be included in an upcoming scientific publication.

The aim of AEgIS is to measure the effect of the Earth’s gravitational acceleration on antihydrogen. Seeing a different behavior for antimatter than for matter would be a huge surprise, and would indicate that gravity is much more complicated than our present understanding indicates.

In the AEgIS experiment, antihydrogen atoms are made to fly horizontally, dropping by a tiny amount, before colliding with matter. On collision the antihydrogen and matter annihilate, producing a burst of mostly pions and some other particles. These particles then travel through an emulsion containing silver bromide developed by the University of Bern in Switzerland that makes their tracks visible. Tracing these tracks to their point of origin tells the AEgIS team exactly where each annihilation occurred, which in turn allows them to calculate how far each particle travels, and how far the particle’s path drops. From the distance the particles fly and fall the AEGIS team hope to calculate the effect of gravity on antimatter.

AEgIS needs your help to map the paths that particles take through the emulsion. As part of the CERN Summer Webfest some of this year’s summer students have created a web application to map particle tracks. All you have to do is join the dots!

“In principle, tracking could be digitized, but computers can miss tracks that are related, but far apart,” says AEgIS spokesperson Michael Doser, who, inspired by astronomy websites such as Astrowatch and Galaxy Zoo, decided to crowdsource the analysis. “I’m using human pattern recognition – we’re pretty good at seeing things that belong together.”

First test data from AEgIS have been uploaded to the web application directly and have never been analysed before. So you can make a genuine contribution to CERN’s research. The data you provide will be openly available and help physicists at CERN with their analysis of the experiment. The results will be visualized on this page as a 3D Model.

The experiment requires about 1000 antihydrogen annihilations for a statistically significant observation, says Doser, but he hopes to have anywhere from 10,000 to 100,000 particle tracks analysed to check AEgIS’s algorithms for even tiny biases.

“Algorithms are not curious,” says Doser. “If we had something unexpected, a computer may not see it. But humans are open to new ways of looking at things. And besides, it’s fun!”

Epilepsy warning: The particle tracks contain rapidly flashing screens. If you are epileptic, perhaps best to skip this bit.

Analyse AEgIS data now!



This article appeared in Fermilab Today on Aug. 8, 2013.

Bill Dymond (foreground) and Paul Schild, AD, work on one of the new 53-MHz cavities for the Recycler upgrade. Photo: Denton Morris, AD

Bill Dymond (foreground) and Paul Schild, AD, work on one of the new 53-MHz cavities for the Recycler upgrade. Photo: Denton Morris, Fermilab Accelerator Division

A beam of protons whizzed through the Main Injector for the first time in over a year on July 30, representing a major milestone in the year-long process of overhauling the Fermilab accelerator complex. The upgrade will eventually culminate in an accelerator with double the power it had previously.

“The shutdown has been challenging, and we all look forward to returning to beam operations and providing beam to the experiments,” said Dave Capista, an engineering physicist in the Accelerator Division. “It is exciting for us to see the results of our hard work.”

The upgraded accelerator complex will push the laboratory’s Intensity Frontier program forward, ultimately delivering high-intensity beams efficiently to the many current experiments that use it and to the future Muon g-2 and Mu2e experiments.

Upgrading the complex requires an elaborate choreography of four main pieces: the Linac, the Booster, the Recycler and the Main Injector. Prior to the 2012 shutdown, the Main Injector and Recycler operated mostly independently. The primary change in the new system is the ability to move beam manipulation functions out of the Main Injector and into the Recycler, allowing the two to coordinate operations to deliver more beam in less time, resulting in more powerful beams.

Now that the Main Injector has seen beam, the laboratory will begin gradually ramping up accelerator operations.

With the Main Injector now operational, it can send low-intensity beam to the NuMI target and the Switchyard so experiments such as NOvA and SeaQuest can begin to commission their equipment. Within a few weeks, the Accelerator Division hopes to begin running beam through the Recycler so commissioning can begin there as well.

“Once you have all the equipment functioning and doing its job, then it’s a case of sitting down and doing the tuning and understanding how the machine behaves,” said Phil Adamson, a scientist in the Main Injector Department. “It’ll be a fun period. There are a lot of systems, so there are a lot of things to do. It will take time.”

Although the Recycler isn’t operational yet, in the coming months the Accelerator Division will begin running beam through it and hope to have the Recycler and Main Injector working together by the end of the year. Ultimately, the Fermilab accelerator will deliver beams of up to 700 kilowatts, instead of the current maximum of 350.

“It’s simply about trying to deliver as much as we can to all the customers that we have,” said Duane Newhart, deputy department head of the Operations Department. “We have a lot. And we hope to have more.”

As the beam is ramped up to greater intensities, the Accelerator Division will monitor how the machines handle it and make adjustments as it goes along.

“When you get to the highest intensities, that’s where you find all the edges,” Adamson said. “At the lower intensities everything works fairly easily, but when you start pushing intensity as high as you can go, all the interesting features start to show up.”

Fermilab will celebrate the restart of the accelerator complex in the fall.

Laura Dattaro


Wedding Cake

Wednesday, August 7th, 2013
My wedding cake

My wedding cake

The decorations on our wedding cake feature one of my wife’s hobbies and one of mine. Can you identify both?

Cake by Clare Brown.  Photograph by Malcolm Anderson.


Snowmass: in Frontierland

Tuesday, August 6th, 2013

What an interesting but exhausting week it has been here at the Snowmass workshop in Minneapolis. I wrote last week about the opening of the workshop. In the following days, we followed what seemed to me like a pretty original schedule for a workshop. Each morning, we bifurcated (or multi-furcated, if that’s a word) into overlapping parallel sessions in which the various working groups were trying to finalize their studies. There were joint sessions between groups, in which, for instance, people studying some physics frontier were interacting with the people studying the facilities or instrumentation needed to realize the physics goals. Every afternoon we have gathered for plenary (or semi-plenary) sessions, featuring short talks on the theory and experimental work undergirding some physics topic, followed by a discussion of “tough questions” about the topic that challenged its importance in the grand scheme of things and the value of pursuing an experimental program on it. We would close each day with a panel discussion on broader policy questions, such as what is the proper balance between domestic and off-shore facilities, or how to make the case for long-term science.

It is a lot of work to put together and participate in a program like this, and overall everyone did a great job of giving well-prepared and thoughtful presentations. I should also take this opportunity to thank our hosts at the University of Minnesota for their successful management of a complicated and ever-evolving program that involved 700 physicists, most of whom registered at the last minute. (And special personal thanks to my Minneapolis in-laws, who made my visit easy!)

We’ve now gotten through the closing sessions, in which we heard summary reports from all the “frontier” working groups. I’m still digesting what everyone had to say, but here is one thing I think I know: there is general agreement that the frontiers that we are organizing our science around are not themselves science topics but approaches that can tell us about many different topics in different ways. For instance, I was quite taken with the news that cosmology can help us set bounds on the total mass of the different kinds of neutrinos; this will help us understand the neutrino spectrum with complementary information to that provided by accelerator-based neutrino experiments. Everyone is really looking to the other “frontiers” to see how we can create a program of research that can attack important physics questions in the most comprehensive possible way. And I think that a number of speakers have gone out of their way to point out that discoveries on someone else’s “frontier” may fundamentally change our understanding of the world.

(On a related note, it is also clear that we are all bothered by the tyranny of Venn diagrams. I am hoping to find time to write again about how many times a graphic of three intersecting circles appeared over the course of the week, and what amount of irony was implied each time.)

Since this the US LHC blog, I should also mention that the LHC came out well in the discussions. It is clear that there is a lot of potential for understanding and discovery at this machine, both when we increase the energy in 2015 and when we (hopefully) run in a high-luminosity mode later on in which we will attempt to increase the size of the dataset by a factor of ten. We expect to learn a tremendous amount about the newly-discovered, very strange Higgs boson, and hope to discover TeV-scale particles that make it possible for the Higgs to be what it is. From a more practical point of view, it is currently the only high-energy particle collider operating in this world, and it will stay this way for at least a decade. We must do everything we can to exploit the capabilities of this unique facility.

Where do we go from here? The results of the workshop, the handiwork of hundreds of physicists working over the course of a year, will get written up as a report that is meant to inform future deliberations. It is quite clear that we have more projects that have great physics potential, and that we really want to execute, than we have the resources to execute. In some ways, it is a good problem to have. But some hard choices will have to be made, and it won’t be long until we have convened a Particle Physics Project Prioritization Panel that will be charged with making recommendations on how we do this. I’m in no position to guess the outcome, but whatever it turns out to be, I suspect that our entire field is going to have to stand behind it and advocate it if we are to realize any, if not all, of our visions of the frontiers of particle physics.


The Aussies have landed

Sunday, August 4th, 2013

It’s just another average day on the CERN student summer programme. I attend lectures, have lunch with the crew and cycle across to Prévessin in glorious sunlight. I sweatily open the door to my office and to my surprise am confronted by four grinning Aussies – “G’day mate”.

You’ve already met my summie office mate Josh. Roger is Josh’s professor from Melbourne University. Mark is a director from the Australian Synchrotron outside Melbourne. And Tom was a summer student last year and will be here to work for a few weeks.

Tom - takes laboratory safety seriously.

Tom – takes laboratory safety seriously.

The Aussies have descended as they collaborate with CERN on developing beam position monitoring systems for both the Large Hadron Collider (LHC) and the Australian Synchrotron.

The banter flows freely and I am invited along to dinner.

Now there are many fine eating establishments in Geneva but I was pleasantly surprised to arrive at a grill next to CERN where the waiters bring out raw meat on a plate to barbecue yourself at the table. I should have known…

Interestingly Roger and Mark have travelled to CERN with Chris Henschke, a Melbournian artist who was previously in residence at the Australian Synchrotron. During his visit he meets up with CERN’s resident artist Bill Fontana. Bill does some fascinating work on the sounds of the LHC and is yet to reveal his centrepiece sculpture – “Acoustic Time Travel”.

It’s a great evening. There are some Australian teachers across undertaking training at CERN so, along with the artists, physcists, some CERN big cheeses and an Irish fella, it makes for a colourful night.

The evening ends with an invite to visit the lads in Melbourne. Um – yes please!