NERSC-SLAC Collaborations Apply Scientific Computing To Experimental High Energy and Nuclear Physics

May 29, 1998

By Jon Bashor,

Berkeley Lab and the Stanford Linear Accelerator Center have a long history of collaboration stemming from their high energy physics research. Now the two facilities are leveraging their resources in the cutting edge area of scientific computing.

BaBar magnet
Among the NERSC-SLAC collaborations in high energy and nuclear physics is the experiment known as BaBar. BaBar's magnet is pictured here.

Examples range from sharing experiences with software applications to developing new systems for gathering, organizing and analyzing data from the upcoming series of particle experiments known as BaBar.

Enhancing scientific computing among DOE labs was one of the objectives of the 1996 move of the Energy Sciences Network and the National Energy Research Scientific Computing Center (NERSC) to Berkeley Lab. Richard Mount, director of SLAC Computing Services, says the move is already bridging what had been a big gap between the scientific computing community and the scientific data processing fraternity within high energy and nuclear physics.

The proximity of the two DOE facilities, combined with the convergence of scientific computing and scientific data processing, are providing new avenues for cooperation.

"There has been a real effort by NERSC to move into scientific computing and scientific data management," Mount said. "There is also a strong direction in high energy physics toward increasingly data intensive experiments. We're seeing a strong effort to seek out common solutions, to seek out new possibilities."

One focal point of this effort is DOE's High Energy and Nuclear Physics Data Grand Challenge to develop tools to allow high energy and nuclear physicists to analyze and manage the massive amounts of data from future experiments, such as those planned for the Relativistic Heavy Ion Collider at Brookhaven National Lab. These experiments, aimed at understanding quarks and other exotic forms of matter formed in the wake of the Big Bang, will generate huge amounts of data--hundreds of terabytes a year.

A large part of the challenge in the early stages will be to predict data-access and computational problems and find ways to solve them. NERSC and SLAC are both working on the problem.

The Computing Sciences organization at Berkeley Lab has several groups working on scientific computing solutions to high energy physics problems. These include the Visualization, Distributed Collaboration, HENP Support, Scientific Computing, Scientific Data Management, and HEP Computing groups.

"The scientific computing problems challenging high energy physics are also showing up in other fields of research," says NERSC director Horst Simon. "Genomics researchers also must find ways to organize and access vast banks of data. Computing Sciences is working on solutions covering many aspects of research, from gathering data from experiments, to organizing, analyzing and presenting the data in useful ways."

For example, the six-person HENP Support Group in the Lab's Information and Computing Sciences Division is designing computer tools to help with the BaBar experiments to be conducted at the "B Factory" being built at SLAC. The goal is to measure the decays of subatomic particles and anti-particles known as mesons. To acquire a sufficient sample of those decays that can reveal fundamental differences between matter and anti-matter, researchers will need to perform up to one billion experiments a year, yielding 150 terabytes of data. They will then need powerful statistical analysis tools to analyze the information.

"This is the most advanced software project in high energy nuclear physics today," said Information and Computing Sciences Division leader Stu Loken. "Ex-periments at future particle detectors will depend on the work we're doing for BaBar."

About 500 physicists in 10 countries are participating in this project and need access to the data, which will be stored in NERSC's High Performance Storage Systems. "We really feel we are welcome collaborators," Mount said.

This situation is a turnaround from the early 1980s, when high energy physics experiment data were recorded on magnetic tapes, and it was not uncommon to fill 10,000 tapes with data. Showing up at a supercomputing center with the equivalent of two truckloads of tape to process did not produce a warm reception at a time when the machines were less powerful, with limited tape handling facilities, Mount said.

To enhance the collaboration between the two facilities, SLAC now provides office space to NERSC employees who live in the South Bay and Peninsula and choose to telecommute. Employees from both facilities routinely work at each other's sites, applying their expertise and drawing upon that of their counterparts. And Berkeley Lab's Stu Loken and Carl Eben, deputy division leader of ICSD, serve on SLAC's computing review committee.

"Our respective resources put us in a unique position to contribute to the Department of Energy and the nation as a whole," Mount said. "I see this growing cooperation as a strategic effort, not just a technical sideline."

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