IOU for a particle physics detector

August 29, 2008 | 7:50 am

Savings by building a neutrino detector with nearly all recycled parts: $3.2 million.

Savings by constructing a small experiment hall: $3 million.

Being able to design, build, and tear down an experiment in less than three years: priceless.

In an era when high-energy physics experiments, and sometimes their approval processes, can last decades, it’s an increasing rarity to find a project that lets collaborators work on all aspects of the research from start to finish.

“It’s good to save money, but it also saves time, which is good so that young students working on their PhDs have time to build an experiment, take the data, and do analysis,” says SciBooNE cospokesperson Tsuyoshi Nakaya.

The 65 collaborators on SciBooNE, a low-energy range neutrino experiment at Fermi National Accelerator Laboratory, last week celebrated the completion and decommissioning of one of high-energy physics shortest and cheapest fixed-target experiments.

The international collaboration of Japanese, Americans, British, Spanish, and Italians formed in the summer of 2005 and had a detector commissioned by May 2007. Data-taking ended this month.

The entire experiment cost $1.2 million, a drop in the bucket for high-energy physics research. The majority of that cost, $850,000, came from constructing a building to house the detector, but even that was a steal. The collaboration made the building as small as possible by utilizing other areas in the laboratory to assemble the three subdetectors. Constructing an experiment hall large enough for assembly would have pushed the construction cost from $800,000 to nearly $3 million. The experiment building is so small that the collaboration had to order a portable toilet for use during the nearly three weeks of decommissioning.

All but a handful of parts were borrowed to build the subdetectors, earning the collaboration a top-notch environmental protection award.

Tona Kunz

2 Comments »

Dark matter illuminated

August 28, 2008 | 10:30 am

by Steve Allen and Maruša Bradač

A new study reveals clear evidence of dark matter (blue), separated from ordinary, luminous matter (red) by a merger of galactic subclusters. (Photo courtesy of Maruša Bradač.)

A new study of an immense cosmic collision has provided confirming evidence for dark matter. Our team analyzed the mass content of the enormous, merging galaxy cluster MACSJ0025.4-1222 using the Hubble and Chandra Space Telescopes to disentangle dark and normal matter—that is, matter made up of baryons, common subatomic particles such as protons and neutrons. The new results confirm those obtained from the 2006 study of the Bullet Cluster, providing a clear view of dark matter, separated from ordinary baryons.

The study examines the aftermath of a merger between two giant sub-clusters, each a whopping million billion times the mass of the sun. As these collided at millions of miles per hour, most of the normal, baryonic matter in each—in the form of hot, X-ray emitting gas—interacted with the similar matter in the other and slowed down, like a diver encountering the water’s surface. In contrast, the dark matter did not interact significantly and passed through without disruption. This difference caused the dark matter to sail ahead, leaving the X-ray luminous, baryonic matter lagging behind.

Read the rest of this entry »

Guest author

3 Comments »

Can you predict Nobel Prize winners by counting citations?

August 27, 2008 | 8:11 am

The Nobel Prize Medal for Physics and Chemistry

In this recently posted paper, Yves Gingras and Matthew L. Wallace analyze the bibliometrics surrounding the physics and chemistry Nobel Prize winners and nominees of the past 106 years. They were curious: Could we predict the winners of the upcoming Nobel Prizes on the basis of how often their work is cited by other scientists?

The answer turns out to be no.

In the first half of the 1900s, citations did have some predictive power. A scientist would make a crucial discovery and write a paper (or papers) about it in a scientific journal. Other researchers would then cite these results in their own publications. Just about the time the scientist’s papers became the most heavily cited in the field, he or she would be awarded a Nobel.

In the last 30 years, however, it appears that physics–and chemistry as well–have become larger and more diverse, so that citations are spread among many seminal papers and researchers. Nobel laureates are no longer necessarily near the top of the citation rankings at the time of their awards.

Read the rest of this entry »

Travis Brooks

5 Comments »

GLAST Observatory renamed for Fermi, reveals entire gamma-ray sky

August 26, 2008 | 1:01 pm

Fermi Gamma-ray Space Telescope "first light" all-sky gamma-ray map

The US Department of Energy (DOE) and NASA announced today that the Gamma-Ray Large Area Space Telescope (GLAST) has revealed its first all-sky map in gamma rays. The onboard Large Area Telescope’s (LAT) all-sky image—which shows the glowing gas of the Milky Way, blinking pulsars, and a flaring galaxy billions of light-years away—was created using only 95 hours of “first light” observations, compared with past missions which took years to produce a similar image. Scientists expect the telescope will discover many new pulsars in our own galaxy, reveal powerful processes near super-massive black holes at the cores of thousands of active galaxies, and enable a search for signs of new physical laws.

The NASA mission was made possible by collaboration with many US and international partners. As part of its support for particle physics research, DOE contributed funding to the LAT—the primary instrument on GLAST—and DOE’s Stanford Linear Accelerator Center (SLAC) managed the LAT construction. SLAC also played a key role in assembling the instrument and now plays the central role in LAT science operations, data processing and making scientific data available to collaborators for analysis.

Read the rest of this entry »

David Harris

1 Comment »

Free online: Full documentation for the Large Hadron Collider

August 25, 2008 | 5:00 am

Figure 2.1: Schematic layout of the LHC

Want to read every single technical detail of the design and construction of the Large Hadron Collider and its six detectors?  The whole shebang–seven reports totalling 1600 pages, with contributions from 8000 scientists and engineers–is available here, published electronically by the Journal of Instrumentation.

According to Friday’s CERN Bulletin:

For many years to come, these papers will serve as key references for the stream of scientific results that will begin to emerge from the LHC after the first collisions that are expected later this year.  Although published in a refereed scientific journal, the articles will be completely free to download and to read on the Internet under an “Open Access” scheme, without requiring a journal subscription.

“This is a landmark publication in many respects,” says ATLAS physicist Rudiger Voss, who has coordinated the project since it started in late 2005.  “It is probably the first time in the history of particle physics that a major new accelerator project has been documented in such a comprehensive, coherent and up-to-date manner before it goes into operation.”

Another long, boring technical document to gather virtual dust on virtual shelves?

Not at all, judging from the continued popularity of The Stanford Two-Mile Accelerator, affectionately known as The Blue Book, which was published in 1968 to preserve the knowledge and experience gained in building the SLAC linac. The recent struggle to make it available to a wide audience shows what a milestone the open-access publication of the LHC documentation is.

Read the rest of this entry »

Glennda Chui

10 Comments »

The Paul Revere of pulses

August 22, 2008 | 6:55 am

From a person’s point of view, the beam of electrons driving down the linear accelerator at close to the speed of light would appear as a single thread. “But from the point of view of precision electronics,” explains Jachin Spencer, “you might see something, you might see nothing.”

To a non-specialist, the word “beam” may be associated with columns of material or light. But on a microsecond time scale, the beam in an accelerator is actually a series of electron-bunches, more like machine gun fire than a shaft of sunshine.

Spencer, a summer student in the SULI program at the Stanford Linear Accelerator Center, is studying the performance of what is called the “fiducial pulse,” a pulse of electromagnetic waves used to coordinate the timing of the accelerator. It’s the job of the fiducial pulse, Spencer says, to let electronics know “when they can look at the beam, when there’s something to see.”

Read the rest of this entry »

Zoë Macintosh

No Comments »

Physicists shine light on the human brain

August 21, 2008 | 5:00 am

Illustration by Laura Randall, Science Illustration Program, UC Santa Cruz Extension.

The UC-Santa Cruz Science Communication Program puts out an annual magazine, Science Notes, showcasing the work of its students.  (Full disclosure: I teach in the program, and boy are they a talented bunch!  Check out what some of the graduates are doing here.)   In the current issue, Amber Dance describes how scientists at Stanford Linear Accelerator are using a beam of bright light to look for metal deposits in the human brain:

[Uwe] Bergmann’s light is a hair-thin beam of sizzling X-rays, shed by a 75-meter-across circular tube called a synchrotron. In recent years, he’s become SLAC’s resident guru for anyone who wants to put something unusual in the beam line—from ancient manuscripts to body parts to fossils. For his next trick, Bergmann is focusing his rays on preserved brain tissue, sliced like a loaf of bread.

Read the rest of this entry »

Glennda Chui

No Comments »

The safety of switching on the Large Hadron Collider

August 20, 2008 | 8:35 am

Most people interested in the Large Hadron Collider have heard about recent grumblings from a small, dedicated cadre who believe that the risks of starting up the LHC are unacceptable, primarily because they think it could create microscopic black holes that would destroy the Earth.

Although this argument had been refuted many times, and repeated safety studies commissioned by CERN have agreed that the risk is negligible, a new essay is well worth reading. Michael Peskin, from Stanford Linear Accelerator Center, has penned a viewpoint for the American Physical Society’s new online publication, titled Physics.

In it, he discusses the recent technical paper by Giddings and Mangano (G&M) on the risks of black hole production at the LHC. The paper itself is long and probably only readable by scientists, but Peskin’s viewpoint summarises the main arguments admirably clearly. As readers following this topic know, there is a negligible risk, but Peskin relates the quite fascinating contortions that G&M go through to try to find a significant risk before disposing of all those arguments.

If you haven’t read a discussion of this issue but would like to find out a bit more than the newspapers have discussed, Peskin’s viewpoint is well worth reading.

There is a lot of good stuff in Physics and so you might want to add its RSS feed to your feed reader. And you do have symmetry breaking coming in by RSS to your feed reader already, don’t you?

David Harris

10 Comments »

ArgoNeuTs see first events

August 19, 2008 | 9:05 am

A group of scientists known as the ArgoNeuTs—a word play on the Argonauts, the heroes of Greek mythology—have overcome the first hurdle in their scientific quest to observe neutrinos. In an e-mail to his colleagues, ArgoNeuT collaborator Flavio Cavanna wrote on Saturday, August 9:

“Dear ArgoNeuTs: After sailing across deep sea for about a week, with just few fire-breathing oxens and sleepless dragons found here and there, the first harbor of the long trip of the ArgoNeuTs to retrieve the Golden Neutrino Event now has been reached–a first cosmic ray event in liquid argon has been just recorded!!”

Flavio Cavanna points at an image of the first tracks, taped to the ArgoNeuT detector.

Less than a week before he wrote his e-mail, Cavanna and his collaborators filled their particle detector with liquid argon to catch cosmic rays. The text of his email refers to an article in the August issue of symmetry, which says:

“According to Greek mythology, the Argonauts were adventurers who sailed across the Mediterranean Sea in their ship, the Argo, to retrieve the Golden Fleece. Led by Jason, the crew braved fire-breathing oxen and sleepless dragons.”

ArgoNeuT stands for the Argon Neutrino Test project at Fermi National Accelerator Laboratory in Batavia, Illinois. The ArgoNeuT collaboration comprises about 20 scientists from six institutions. Their particle detector relies on liquid argon–cooled to a temperature of minus 187 degrees Celsius–to catch neutrinos. (To learn how the detector works, check out the graphic at the end of the symmetry article.)

Read the rest of this entry »

Kurt Riesselmann

2 Comments »

Can science be funny?

August 18, 2008 | 11:26 am

The owners of the Punch Line Comedy Club in San Francisco weren’t too sure when they hosted Brian Malow, self-styled “science comedian” on August 11, 2008. Pre-bookings were slow and the club had only two servers working a room that can seat over 200. But as the start time drew closer the room filled to capacity.

Malow started performing general stand-up comedy but found that his audiences would respond well to bits he did based on topical science. Over time he began to specialize and now does full stand-up shows with a science theme, and is often booked by scientific organizations as entertainment.

I’ll admit that I was quite skeptical about whether the show would be genuinely funny, or just appeal to my inner geek. I’ve seen quite a few people try to make comedy from science, but rarely have they reached a level of actual comedy that might be of general interest. Instead they have merely been a set of statements designed to appeal to a shared sense of geekiness between performer and audience.

The warm-up act was a science teacher who writes jokes for Jay Leno on the side. Although he drew a few chuckles, the audience would have preferred he stick to writing jokes rather than performing them.

When Malow appeared on stage, the whole vibe in the room changed. This was a performer who was at home on stage, and was prepared to entertain. From the start, Malow had the audience laughing loudly and only a few times was he met with a withering silence. However, he handled those little deaths quite well and got on with the show, bringing the audience back around.

Read the rest of this entry »

David Harris

5 Comments »