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Michael Banks: July 2009 Archives

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Peak time

By Michael Banks

When submitting an article to the arXiv preprint server you might not think it matters when in the day you do it.

But according to new analysis by the server’s founder Paul Ginsparg and Asif-ul Haque from Cornell University, it does, and it could affect how many citations the paper will receive.

They looked at arXiv paper submissions between 2002 and 2004 in three categories: astrophysics (astro-ph), high energy physics - theory (hep-th) and high energy physics - phenomenology (hep-ph).

They found that papers appearing at the top of the list each day generated more citations than papers lower down.

Researchers can submit articles to arXiv at any time of the day. However, there is a cut-off point at 4pm eastern time (EST) for papers to appear on the server on the same day, which are then published at 8pm.

Articles submitted just after 4pm EST will be published the next day. The first paper to be submitted in a certain category after this cut-off time will then be top of the following day’s list.

Interestingly enough, Haque and Ginsparg see a spike in submissions to the server just after 4pm EST (see above chart for submissions to hep-ph) as physicists jostle for top position on the next day.

Physicists’ instincts for trying to land top spot are now backed up by evidence.

Haque and Ginsparg find that papers appearing in the number one position in the astrophysics category, overall, received a median number of citations 83% higher than other papers on that day.

Articles in hep-ph taking the top four places received a median number of citations 100% higher than those published in positions 5-15. For articles in hep-th it was 50% higher.

They also found that the position of the article on arXiv also affected how many full text downloads it had.

Articles taking the daily number one spot in astro-ph, hep-th and hep-ph received a median number of downloads 82%, 61% and 58% higher than that for lower positioned articles, respectively.

This means that it is good news if you are a researcher in the US itching to get the number one spot.

However, researchers in the UK would have to wait until midnight to get a chance of being top, while researchers in Japan would have to get into the office bright and early just after 8am to secure top spot.

So when you submit your next paper to the arXiv remember to keep an eye on the time.

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Catching up on the latest physics

By Michael Banks

Sorry, not at CERN’s Large Hadron Collider near Geneva or Fermilab’s Tevatron in Batavia, Illinois, but at our office here in Bristol.

This morning, Physics World’s postbag contained our very own Higgs boson plush toy sent from Julie Peasley at Particle Zoo.

Particle Zoo, based in Los Angeles, makes plush toys of all your favourite particles including the neutron, electron as well as particles that have not yet been discovered such as the graviton.

Recently, Particle Zoo even branched out from just making particles to produce a plush toy of the cosmic microwave background and higher-dimensional “branes”.

Physics World can confirm that the mass of the Higgs is surprisingly large and that it is currently taking pride of place in the office next to the latest issue of the magazine.

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The target station at the Material Life-Science Facility

By Michael Banks

The paint has yet to dry here at the J-PARC experimental complex in Tokai, Japan.

Today I visited the Material Life-Science Facility (MLF), which produces neutrons and muons that are used in a variety of experiments in materials science to biology.

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under wraps…for now

At J-PARC, a 3 GeV synchrotron feeds the MLF with a intense beam of protons that are then smashed into a 20 tonne mercury target to produce neutrons.

Theses neutrons are then cooled using a water moderator before being sent to a maximum of 23 experimental stations.

If you like your research equipment brand new, then you have come to the right place. I could not find a single piece of kit that looked used. Even the box containing spanners looked like it had just been opened that morning.

So far 15 instruments at the MLF have been funded by the Japanese government and eight have already been built at a total cost of around $70m.

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A crystal diffrotometer – the ‘cage’ – for biological samples

The MLF has been operational since May 2008 when it produced its first neutron beam. At the moment, however, the beam has a power of 18 kW, which when fully operational is expected to reach 1 MW (the ISIS neutron source in Oxfordshire, for example, operates at 160 kW).

According to Masatoshi Arai, deputy director of the MLF, training the beam to full power will take around five years to complete.

The MLF has already had its first users. From the 100 proposals submitted last September for beamtime, 10% were from scientists based abroad, 10% from industry and the rest from scientists in Japan.

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Inside the target chamber

Interestingly, Aria told me that the Japanese government would only fund the MLF if it gave 25% of its beamtime to industry users – a decision that was reached at a meeting in 2000 that lasted until 5am in the morning after a full night of negotiations.

It was not only a great opportunity to walk around the facility and squeeze into all the sample rooms, but I also had the chance to see inside the mercury target chamber.

Once a high-powered beam has been used at the facility, access to the target chamber is strictly off limits due to the increase in radiation levels. Indeed, 1m deep perspex ‘windows’ are used to look into the target chamber.

Aria has spent the last nine years fully focused on getting the facility finished and is now looking forward to returning to his research into superconductivity.

Yet he isn’t quite finished thinking about the next steps for the MLF. “It is early days, but we already have plans for a second target station and then even more experiments,” says Aria.

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Shoji Nagamiya, director of J-PARC, outlines the accelerator complex

By Michael Banks

Imagine having a world-leading neutron and muon source, a particle accelerator capable of boosting protons to 50 GeV, and a neutrino facility all on one site.

Well, you don’t have to any longer, as this is exactly what the $1.5bn J-PARC accelerator complex in Tokai, 100 km north of Tokyo, has to offer.

Today, physicists from around the world, myself included, met in Tokyo to celebrate the opening of the J-PARC accelerator complex after 12 years of construction.

The main aspects of J-PARC revolve around its 3 and 50 GeV synchrotrons. The 3 GeV synchrotron ramps up a beam of protons to smash them into a mercury target producing copious amounts of neutrons and muons that are then used in a range of experiments in biology to condensed-matter physics.

Meanwhile, the 50 GeV synchrotron, which is currently only operating at 30 GeV, accelerates protons before smashing them into a graphite target to produce kaons and neutrinos.

The inauguration held at the Kudan Kaikan centre in central Tokyo was attended by around 1000 scientists.

First to speak was Shoji Nagamiya, director of J-PARC, who has been with the project since its inception in 1999.

Unfortunately, during my few days in Tokyo I haven’t yet picked up the language, so I didn’t understand most of his or the other talks as they were given in Japanese.

After Nagamiya came a roster of dignitaries to the stage to offer their congratulations for the completion of J-PARC. These included the Japanese science minister, Ryu Shionoya, as well as Akito Arima, the former Japanese education minister and Masaru Hashimoto, governor of the Ibaraki prefecture, where J-PARC is based.

Next up was Makoto Kobayashi from the KEK lab, who shared the 2008 Nobel Prize with Yoichiro Nambu from the University of Chicago and Toshihide Maskawa from Kyoto University. Kobayashi gave a brief lecture about the new science that J-PARC hopes to unveil.

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Steve Koonin gives a recorded message of congratulations

Steve Koonin, under secretary for science at the US Department of Energy also give a brief recorded message (in English) of congratulations saying that J-PARC represented “another great venture in Japanese science”.

After the talks had finished, scientists from other countries who helped to build J-PARC were named and invited to the stage.

Then Nagamiya flashed a slide up saying that any foreigner in attendance should come to the stage.

I couldn’t really hide away and was duly encouraged to go on the stage along with some other members from the audience.

I felt somewhat embarrassed to be applauded by over 500 Japanese scientists, but it was a nice touch to the event.

However, it was not all about talks and being red-faced on stage and after the talks a lavish banquet was put on with sushi and sashimi.

After the inauguration I caught up with Nagamiya, who said it was not always easy to build such a big lab that was a partnership between the KEK lab and the Japan Atomic Energy Agency. “Now I feel confident about the project,” says Nagamiya, “but when I started I was less confident. What is especially pleasing is that the world is leaning towards new neutron and neutrino facilities, so we are setting the trends.”

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The Cheomseongdae observatory

By Michael Banks

Being the International Year of Astronomy, what better time than to go and see Asia’s oldest surviving observatory.

The Cheomseongdae (star-gazing tower) observatory in Gyeongyu, South Korea, dates back to the seventh century and was built during the reign of Queen Seondoek of Silla.

The Silla dynasty began in 57 BC and reigned for almost 1000 years. It was one of the three kingdoms that ruled in Korea, but by 660 AD it had occupied the other two kingdoms - Baekje and Goguryeo — to rule most of the Korean peninsula.

The observatory is around 9m high and is built by 356 stones representing each day in the year. Seemingly everything about the construction of the observatory has some meaning. The observatory has 27 layers of stones as it is thought that Queen Seondoek was Silla’s 27th ruler. Then, above and below the opening is 12 layers of stone for every month in the year.

The Queen’s astronomer would climb to the top of the observatory every day to take a view the sky. Using a ladder, he would clamber through the opening in the observatory and then climb to the top. There he would give information to the Queen about weather patterns and the timings of any solar eclipse.

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The Pohang Accelerator Laboratory

By Michael Banks

The number of synchrotrons in the world seems to be increasing with every month that passes by. Indeed, only a few months ago the Shanghai Synchrotron Radiation Facility China started experiments, closely followed by the PETRA III light source in Hamburg, Germany - adding to the 50 or so light sources operational worldwide.

Synchrotrons are used by researchers for a range of experiments in everything from condensed-matter physics to biomedicine by providing radiation from the infra-red to hard X-rays that can be used to solve protein structures and study quantum dots.

I visited South Korea’s only synchrotron, the $270m Pohang Accelerator Laboratory (PAL), which is on the Pohang Univeristy of Science and Technology (POSTECH) campus located in the South East of the country.

Opened in 1995, PAL is a 2.5 GeV light source that can house up to 27 beamlines around its 200m circumference.

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A public-private initiative. On the left is POSTECH’s first president, Hogil Kim, and on the right is the former chairman of POSCO, Tae-Joon Park.

Interestingly, I learned that PAL was built with both public and private funding. A local company, POSCO, which is now the world’s second largest steel manufacturer, funded the synchrotron with $190m, with the remainder coming from the Korean government.

PAL is open to scientists from other countries, but most of the experiments are carried out by scientists in Korea. Research carried out at the synchrotron now leads to over 8000 published papers every year with around 60% of them in international journals.

Researchers at POSTECH, which operates and owns PAL, are now hoping to upgrade the synchrotron to increase the number of beamlines as well as increasing its energy to 3 GeV. If the Korean government funds the upgrade it will begin construction late next year

South Korea also has other ambitious plans for an X-ray free electron laser facility — so-called fourth generation light source — that is only just in the proposal phase. If it is built then it would be situated next to PAL on the POSTECH campus making Pohang a leading centre for research in East Asia.