Posts by: Jon Cartwright

The LHC, one week later

By Jon Cartwright

Many of you will be wondering how the Large Hadron Collider (LHC) has been getting on since last Wednesday’s celebrated “switch on”. Well, if you are willing to overlook one 30 tonne hitch, commissioning is still going well.

On the switch-on day itself, if for some reason you left the planet, the operations team managed to get proton bunches all the way around the LHC’s 27 km-long ring in both directions. But even though the media had trickled away by early evening, the LHC team didn’t stop ploughing ahead, as I discovered when I went to the control centre the morning after. By then they had already had an anticlockwise bunch endlessly circulating, albeit spread or “de-bunched” around most of the ring. To correct the de-bunching, the team initiated their radio-frequency systems, which by Friday had been successfully tuned in both frequency and phase.

Friday, unfortunately, also brought difficulties. A transformer weighing some 30 tonnes developed a short circuit, forcing the team to replace it. As I hear from Lyn Evans, the LHC project leader, the new transformer has been lifted into place and the electrical systems, which feed the vital cryogenics systems, should soon be back on line.

The good news, however, is that Evans is planning to try some low-energy collisions next week. Hang on to your hats.

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LHC switch-on: a preview

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The LHC control room (heavy lever obscured from view).

By Jon Cartwright

Until a few months back I had an excited vision of the moment the great LHC “switch on” would take place. Here’s how it goes: The control room, normally frantic with the workings of scientists, falls under tense silence as a lone technician grips a heavy lever. Just as the quiet becomes unbearable, the director general mutters: “OK, let’s go.” Beads of sweat trickling down his temples, the technician heaves back the lever while averting nervously to a dial that has coloured bars going from green to yellow to red (450 GeV…5 TeV…7 TeV…DANGER) . “Faster!” cries the director general, his eyes glowing with a sort of manic intensity, “Faster!” Then the control room begins to shake and the scientists dive under their workstations to avoid the plaster and tiles falling from the ceiling.

Needless to say, the real event tomorrow will not satisfy onlookers with any cinematic clichés (and nor will the beams break any speed records — they will be strictly cruising at their injection energy of 450 GeV). But that’s not to say the event will be without drama, as I found out today when I went to CERN’s Meyrin site for for lunch with Paul Collier, head of the accelerator operations team.

“It’s not like blasting off from Cape Canaveral,” he said, referring to the fact that there is no definite countdown for performing certain tasks. Rather, the operations team will be learning as it goes, and we will get to watch — milestones, mistakes and all. The current plan is to inject the first beam into the ring at around 9:30 am, but it could happen anytime between 9 and 10 am (keep an eye out on this blog for the decisive moment). From then on, the team will take the beam round the LHC’s 27 km-long ring in a dozen or so sections, each initially fenced-off by a physical barrier.

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Bar brief power failure, LHC ready for start up

By Jon Cartwright

In my last blog entry on the Large Hadron Collider (LHC) I asked if CERN could make it to Wednesday without any further difficulties. Well, there’s been one — a thunderstorm-induced power cut that took out the cryogenic systems for the weekend — but other than that it’s all systems go for the eagerly awaited “start up”.

On Friday evening, according to CERN spokesperson James Gillies, the LHC operations team successfully performed a third and final synchronization test. Unlike the previous two tests, which concerned “kicking” proton beams from the Super Proton Synchrotron into the LHC’s ring, the aim on Friday was to make sure the protons could be booted out of the ring at the “beam dump” point located between sectors five and six. The latest test also demonstrated that the team could navigate the protons around two sectors, or about 7 km. That means they’ve already reached 25% of their target for Wednesday, when they plan to get a low-energy beam cruising around the 27 km ring in one direction.

Talking about Wednesday, physicsworld.com is now reporting from CERN to bring you all the news in the run-up to the big day. You can also expect an analysis of the events in the October issue of Physics World.

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Should cameras be banned at conference presentations?

By Jon Cartwright

Physicists used to be able to show preliminary results at conference presentations, safe in the knowledge that no-one would steal their data. Now, with the advent of the “physics paparazzi”, things have changed.

It started a few weeks back when, at a high-energy physics conference in Philadelphia, a member of the PAMELA team flashed a slide that depicted an excess of high-energy positrons in the ionosphere. Although several conference attendees suggested the positron excess could be evidence for dark matter — the elusive substance thought to make up some five-sixths of all matter in the universe — the team did not make the slide available to journalists or other scientists.

That, however, didn’t stop Marco Cirelli of CNRS in France and Alessandro Strumia of INFN in Italy. Those attendees managed to take a snapshot of the slide during its momentary disclosure and use the picture as the basis for an analysis which they published on the arXiv preprint server.

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DAMA results go through the looking glass

By Jon Cartwright

The debate as to whether the DAMA/LIBRA team has detected dark matter, as it claimed in April, will no doubt persist until fresh data can say either way. But in the meantime, Robert Foot, a physicist from the University of Melbourne, suggests an alternative interpretation: “mirror matter”.

I’ll take a step back for a moment in case you aren’t familiar with the story. (Alternatively, you can see Physics World’s feature DAMA/LIBRA is an underground experiment based at the Gran Sasso laboratory in Italy. It looks for dark-matter particles known as WIMPs (weakly interacting massive particles) — a class favoured by theorists for the mysterious substance — by monitoring for flashes that occur when the particles collide with nuclei in 250 kg of sodium-iodide detectors. The idea is that the frequency of flashes should modulate over the year as the Earth changes its speed through our galaxy’s “halo” of dark matter: in June, when the Earth’s orbit takes us faster through the halo, one would expect to see more flashes; in December, when we are moving slower, one would expect to see fewer.

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LHC kicks in both directions

LHCb.jpg
(Credit: Olaf Behrendt)

By Jon Cartwright

Could it be — touch wood — that the Large Hadron Collider (LHC) will make it to the official 10 September start-up date without any further hiccups?

On Friday scientists at the European laboratory CERN were able to tick off two more items on the accelerator’s commissioning list. First, they managed to feed a bunch of protons from the transfer line of the Super Proton Synchrotron (SPS) into the LHC and then steer it some three kilometres round the beam pipe in a counter-clockwise direction. Second, a detector at LHCb — one of the four main experiments at the LHC — got the first taste of collision debris.

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Seeing animals in a new light

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(Credit: Chris Lavers)
galapagos.jpg
(Credit: Chris Lavers)

By Jon Cartwright

At first glance these images look like snapshots from that classic eighties sci-fi flick Predator.

It turns out, though, that the pre-eminent being responsible for them is not a brawny, gun-toting alien, but Chris Lavers, a technology lecturer at Britannia Royal Navy College in Dartmouth, UK. The images are infrared portraits of various animals dwelling at Paignton Zoo in Devon.

“I have been involved in thermal imagery for about 10 years now, and thermal imagery of wildlife with Paignton Zoo since 2002,” writes Lavers in an email. “My interest is concerned with highlighting the plight of endangered species under pressure from both man and climate change, deteriorating environments, etc.”

Lavers explains that thermal images can be used to observe animals without stressing them. “It enables a healthy baseline assessment of animals to be established and thereby aids veterinarian diagnosis,” he writes.

Aside from giving giraffes, tortoises and other creatures a once-over, Lavers is also interested in using thermal imaging to copy some of nature’s designs, such as iridescent butterfly wings. These could be employed in future stealth devices, he says.

If you want to see more of Lavers’s images — and are out and about in the south-west of the UK — you can visit his exhibition. It starts on 15 September at Paignton Zoo, and moves onto the Living Coasts zoo in Torquay until the third week of October.

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In the dark about dark matter

By Jon Cartwright

Has a European satellite detected dark matter? That’s the question on many people’s lips who attended the recent International Conference on High-Energy Physics (ICHEP) in Philadelphia, US.

Several physicists who attended the conference have told me that Mirko Boezio, a representative of the PAMELA (Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics) mission, briefly showed data depicting an excess of high-energy positrons in the ionosphere. If true, it would seem to be evidence of annihilation dark matter — an elusive substance thought to make up some five-sixths of all matter in the universe.

Unfortunately, neither Mirko Boezio nor the principal investigator of PAMELA, Piergiorgio Picozza, wants to comment on their data. They told me this was because they are planning to publish in either Nature or Science, and are therefore prohibited from talking to journalists because of those journals’ embargo policies. (Another little birdie told me that the PAMELA team is specifically aiming to submit to Nature by September, so if they fast-track it we might get to see the paper before Christmas.)

I’m going to tell you all I know about this, because frankly it’s not that much at the moment. The slides available from the ICHEP website only show positron data up to about 6 GeV, which doesn’t show much. Slightly better is this slide below from another PAMELA team member, Elena Vannucinni, who gave a presentation at the recent SLAC Summer Institute.

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NASA the party-pooper

By Jon Cartwright

Fifty years ago today, US President Dwight Eisenhower signed legislation that created the National Aeronautics Space Administration, or NASA.

An important anniversary, you might think. Perhaps some champagne, some fireworks, a speech from NASA boss Michael Griffin? Surprisingly not. With regards to birthday celebrations, the agency has stayed as silent as Beagle 2 over the past few days, with press releases noticeable by their absence.

Yesterday I buzzed press officer Edward Goldstein to see whether anyone was up to anything. “I’ve had a couple of European journalists ask me that,” he said. “But really we’re only recognizing when NASA began operations, on October-first.” Goldstein added that there would be a “big gala” on 24 September (I think he said it would be at the Smithsonian National Air and Space Museum, but my biro skipped over the page at that point).

I asked if anyone might even nip to the pub for a pint or two after work. “You know,” the press officer continued, “maybe I ought to suggest that to the guys.”

Those NASA bods really need to learn how to party.

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Cut the SLAC

SLAC.jpg

By Jon Cartwright

The US Department of Energy (DOE), it would seem, is getting a minor headache trying to come up with a new name for SLAC.

What’s wrong with SLAC, you ask. Well, last year the DOE tried to copyright the description of the acronym, the Stanford Linear Accelerator Center, but was stopped in its tracks by Stanford University, which runs the lab. Apparently the university wanted to hold onto the rights to the word “Stanford”, thus forcing the lab to rename itself.

SLAC isn’t finding it that easy. To help matters, director Persis Drell is pointing imaginative types to a website to suggest acronyms anonymously. Preferably the name should reflect the change in the lab’s mission, she notes.

It is of course customary on these occasions to have an open discussion, so we’ve been racking our brains for ideas. If “Stanford” is out of the question, perhaps just replace the first letter? We could have the Big Linear Accelerator Centre (BLAC), for instance. Or, if synonymy with the original acronym is your game, there’s the Linearly Organised Optimum Science Establishment (LOOSE). (Okay, so that one’s a little contrived.)

As some employees at SLAC have suggested, they could keep the original acronym but change the meaning. How about the Science Lab And Café? (I’ve never been, but I assume there’s somewhere to get a bite to eat.)

Still, the prize for the most cynical must surely go to the author of the blog an American Physics Student in England. He or she has put forward the Fundamental Understanding-of-Nature Discovery MachinE (FUNDMe).

I await your suggestions…

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