signal to background

Tevatron sets world record; the most productive age for research; numbers: Pierre Auger Observatory; bicycle networks; keeping computers cool; opera review: Doctor Atomic.

160 Collider Run II Peak Luminosity 140 (x1030 cm-2sec-1) 120

100

80

60

40

20

0 2 3 4 5 Jun 2002 Jun 2003 Jun 2004 Jun 2005 Dec 200 Dec 200 Dec 200 Dec 200

A bright machine to produce than , and date of publication of the top The Fermilab Tevatron achieved the Tevatron operates at a 25 theoretical papers from the a world-record peak lumi- much higher collision energy spires all-time top-cited list. nosity, or brightness, in colliding of 1960 GeV. The Tevatron Included are the 29 authors protons and antiprotons on record is tied to the startup of whose ages are in the database. October 4, 2005. The luminosity a new technique to cool anti- Some appear more than once

Photo: Reidar Hahn, Fermilab of 141x1030 cm-2sec-1 is about beams, which makes as authors on multiple papers. four times the luminosity the beams more concentrated. Half the authors were 32 achieved three years ago, and Kurt Riesselmann or younger when they published more is expected to come. their famous papers. The chart To maximize the potential Don’t cite anybody shows that the most frequent for scientific discovery, accel- over 30? ages are 29 and 30. In fact, erator experts improve and A common assertion is that almost half the ages are con- tune their machines to produce the best work in physics is centrated around the window the largest number of colli- done by people who are under of 29-30. sions per second, a rate known 30. Is it true? This chart shows Heath O’Connell, Fermilab as the peak luminosity of a the ages of authors at the particle-collider machine. The Tevatron record sur- Ages at publication of top-cited papers Source: spires passes that set in December (http://www.slac.stanford.edu/ 1982 by the ISR collider at library/topcites/2003/alltime.shtml)

10 symmetry | volume 02 issue 09 | november 05 CERN, which collided protons 8 on protons. The ISR achieved 6 a peak luminosity of 140x1030 4 cm-2sec-1 at a collision energy 2 of 62 GeV. 0 0 6 6 0 0 8 8

Why did it take 23 years to 8 2 2 2 2 -5 -4 -2 -3 -4 -2 -5 -3 break the ISR record? Beams -4 49 31 41 23-24 25-26 27 37 47 51 39 53-54 55-56 21 29-3 33-34 35-3 43-44 45-4 of antiprotons are much harder

4 Numbers: Pierre Auger Observatory In November, the Pierre Auger Observatory outside Malargüe, Argentina, celebrates its scien- tific launch. The observatory will record high-energy cosmic-ray showers with ground-based water tank detectors and air- shower cameras. David Harris

3000 Detector area in square a kilometers a 30 Number of times Paris would fit within detector area

1400 Meters above sea level b

739 Current number of water tanks

1600 Eventual number of tanks c

11,000 Liters of water per tank

1500 Meters between water tanks

20 Years of expected lifetime for tanks

3 Current air observation d cameras

440 Photomultiplier tubes per camera e

1500 Events per day recorded b

Photos: Pierre Auger Observatory 140 Highest energy of a recorded event in EeV (exa-electronvolts=1018 eV)

100 Speed in miles/hour of tennis ball with equivalent energy

15 Countries participating

1938 Year Pierre Auger discovered cosmic ray showers

20,000 Population of Malargüe

927 Argentina’s average human popula- c d tion per detector area

81 Argentina’s average llama popula- tion per detector area symmetry | volume 02 issue 09 | november 05

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5 signal to background

extract heat from the air. The cooled air is blown into the 12-inch raised floors of the com- puter rooms. The current system can cool at a rate of 125 watts per square foot, Weisskopf said, but with a yearly increase in the number of computers installed, an ideal system needs to handle 500-600 watts per square foot. “We are at the breaking point for old-fashioned under-floor cooling systems,” Weisskopf says. “We’re stuffing thousands more little hot computers in here, and it’s more and more difficult to power and cool them.” Four air handlers, which resemble 14-foot-long giant refrigerators, have been installed to cool areas of the center that produce excessive amounts of heat. Six more are scheduled for installation before winter. But even those won’t be sufficient for long, Networks of the past available for experimenters to Weisskopf says. By spring 2006, In today’s exper- ride around the site. But Weisskopf hopes to install a iments, it takes a fraction of today’s bike trips are usually to water-cooling system that will Photo: Fermilab a second for data recorded by meetings and seminars, or just deliver cold water to each detectors to be transferred out to lunch. individual computer rack in to a data storage facility. Soon Kurt Riesselmann the center. thereafter, collaboration mem- The ultimate solution is to bers from around the world Hot computers direct chilled water as close to have access to the data via Computing centers are hot– the computers as possible. the Internet. literally. At least, they are in the Some manufacturers are work- Not so thirty years ago. In the absence of extensive cooling ing on cooling systems that 1970s, experimentalists at systems. With an increasing would channel chilled water Fermilab and other labs had no number of computers installed directly to computer chips. networks to transfer their exper- at scientific labs nationwide, But until the plumbing intrica- imental data from the data the efficiency of those cooling cies are solved, water-cooled acquisition system to the places systems is becoming much racks are the best option for where they would store and more important. Just ask John SLAC, Weisskopf says. “If you analyze their data. Their mode Weisskopf, technical opera- get a leak [near a computer of data transfer was rather tions manager at the Stanford chip], you’re in trouble,” he says. low-tech: the bicycle. At the end Linear Accelerator Center. He Kendra Snyder of a shift, a scientist would is responsible for keeping the take the tapes with data, hop on more than 3500 computers in a bike, and ride over to the the laboratory’s main computer computer center or wherever center from overheating. symmetry | volume 02 issue 09 | november 05 the data analysis took place. The cooling process starts This process even received its at SLAC’s water cooling plant, own acronym: BOL, for where nearly 300 tons of “Bicycle Online.” chilled water is circulated to the Today, the Bicycle Online computer center. The water transfer is history. But like is distributed to the building’s

thirty years ago, Fermilab again cooling coils, which work like Photo: Diana Rogers, SLAC has a pool of bicycles that is giant radiators in reverse, to

6 Doctor Atomic: A opera Reviewed by Mary K. Miller,

Particle physics has been getting its due in the theater world with the recent plays Copenhagen and QED, which celebrate the lives and work of famous physicists. Now the field is being paid the highest musical and artistic compliment, inspiring the new opera Doctor Atomic, which had its première in early October by Opera. It tells the story of the Manhattan Project, boiling the action down to a few weeks and hours before the test of the first atomic bomb in Photo: Terrence McCarthy Photo: Terrence April 1945. The opera centers on science director and physicist J. Robert Oppenheimer, his wife God.” After fending off his fellow scientists’ moral Kitty, Edward Teller, General , and objections to the bomb’s use against Japan, the young idealistic scientist, Robert Wilson. he surrenders a moment to his own Faustian Pulitzer-prize winning composer John Adams misgivings. wrote the music and his long-time collaborator The libretto was both intriguing and risky. Peter Sellars directed the opera and cobbled Since Peter Sellars pieced it together from dis- together the libretto from declassified govern- parate sources and compressed the story into ment documents, personal letters, interviews a very short time period, people not familiar with with project participants, and Oppenheimer’s the science or history of the Manhattan Project favorite poetry. may feel dropped into the middle of the action As a science writer at the Exploratorium, with precious little character or plot development. I became involved in this production when the The dialog between physicists was often dense, museum was asked by San Francisco Opera to as when Teller reports that Enrico Fermi was create a companion Web site for the opera, taking bets on whether the bomb test would focusing on the scientific, cultural, and historical ignite Earth’s atmosphere in a vast “chain reac- impact of the atomic bomb. My museum has a tion.” (This was an erroneous bit of physics stake in the story: physicist Frank Oppenheimer, since the question was whether heat from the who founded the Exploratorium in 1969, was blast would ignite a thermonuclear fusion reaction, the younger brother of J. Robert, and worked not a fission chain reaction.) For background, alongside him on the Manhattan Project. it helped to attend the pre-opera lecture and I So it was with great anticipation that I attended appreciated that Adams and Sellars never talked the opera’s première, wondering how the cele- down to the audience but assumed we would brated creators of Doctor Atomic would handle come to the material with our own knowledge, such a complex, momentous event in our nation’s background, and thoughts about atomic weapons history. For the most part, I wasn’t disappointed. and their use. It was a musically thrilling, intellectually chal- Of course, the opera’s dramatic and antici- lenging, and deeply affecting three hours with pated high point comes at the end: the bomb only a few fizzles. John Adams uses a full goes off. In this age of special effects, Adams palate of musical devices, from electronic com- and Sellars were subtle. The countdown to the positions that evoke industrial mayhem, to test stretched out with the orchestra tender passionate duets between Robert and driving relentlessly forward and the chorus shriek- Kitty, to clashing chords and tympani that pulled singing words from the Bhagavad Gita: “I am me to the edge of my seat. The orchestral become Death, the destroyer of worlds.” Then music was at times full of tension and menace, all goes quiet, we see the greenish glow of a foreshadowing the bomb detonation and its distant explosion on the faces of the chorus, and consequences. At other times, it provided quiet then hear the soft voice of a Japanese woman interludes, where the audience could contem- asking for a drink of water–taped testimony symmetry | volume 02 issue 09 | november 05 plate the legacy of this ultimate weapon of from a Hiroshima survivor. Thus, the opera ush- mass destruction. In one of the most gorgeous ers in a new age. passages at the end of Act 1, Oppenheimer is alone with his creation, known by scientists as “the gadget,” singing the words of the John Donne sonnet, “Trinity” (for which the bomb test Explore more of Doctor Atomic at was named): “Batter my heart, three-person’d www.exploratorium.edu/doctoratomic

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