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In this issue:
Parallel Computing Key to Future Success
Safety Today: Tunneling Hazards
SLAC Welcomes New Employees
Deadline Approaches for Ultrafast Summer School
Safety Seconds

SLAC Today

Tuesday - April 10, 2007

Alf Wachsmann displays the orange wires that connect sixty-four computers (not seen in this photo) to the Myrinet switch, allowing them to intelligently share problem-solving tasks.

Parallel Computing Key to Future Success

Sixty-four computers connected to each other by orange wires in the belly of Building 50 made the difference between immediate and postponed glory.

BaBar physicist Brian Petersen and collaborators asked the computers to work together to analyze 1.3 million events from particle collisions. Thanks to parallel computing—where tasks are intelligently shared and therefore done more quickly—Petersen got his answers back in time to present stunning new results at a conference in March. He saved 687 days worth of wall clock time.

Now that computing speed has reached its limit—processing speeds aren't any faster than a few years ago—computer manufacturers are doubling and quadrupling the number of cores, the arithmetic unit inside a processor. "The only way to get a performance increase for your physics program is to make use of parallel computing and multiple cores," said Alf Wachsmann in the Scientific Computing and Computing Services (SCCS) department.

(Column - Safety Today)

Tunneling Hazards

All SLAC employees are probably aware of the ongoing tunneling for the LCLS, which started two weeks ago behind the Collider Hall. Last week excavation progressed past 50 feet; daylight doesn't reach that far in, so crews have had to install supplemental lighting.

Being underground presents many potential hazards for tunnel workers, so special safety measures have to be applied to mitigate these risks. Safety instructor Mickel Seeley explains that the main security measure to follow inside a tunnel is keeping a close eye on the quality of the air to make sure that it's breathable. Workers use an air monitor to check the concentration of oxygen. According to Seeley, the most common poisonous gases that can be found in an excavation tunnel are the diesel fumes coming from the machines in use. Workers must also keep close control of the ventilation system, which has to be permanently open and running.

It is also important to make sure that the steel braces that form the support system of the tunnel are installed correctly to prevent collapses. Seeley explains that tunnel workers mount a sustaining system every four feet into the tunnel, a process overseen by superintendents. This crucial process is often repeated, as the tunnel advances about eight feet per shift. There is currently only one shift working in the tunnel, but it will increase to two beginning next month.

All tunnel crews currently at work at SLAC have taken an 8-hour safety course imparted by Seeley. "Every person that goes inside the tunnel—no matter if they've been tunneling all their life—goes through my course," Seeley says.

SLAC Welcomes
New Employees

(Image - New employees)
Image courtesy of Diana Rogers.

SLAC welcomed 16 new employees last week at orientation. From left to right, they are: Josephine Hsu, Ingrid Ofte, Rick Jackson, Philippe G. Hering, Erik Nelson, Tyler Adams, Leonard Anzalone, Queenie G. Quiazon, Brian Sherin, Monica Morchi, John Fryer, Kevin Herbst, Nicholas Horton, Aaron Monteleone, Greg Hays, and Manuel Carrasco.

Deadline Approaches for Ultrafast Summer School

The Photon Ultrafast Laser Science and Engineering (PULSE) Center will host the 2007 Ultrafast Summer School. This five day residential program will offer comprehensive lectures and an open forum for discussions about free electron lasers (FEL).

Friday, April 20 will be the last day for early registration. Learn more and register online.

Safety Seconds

Pilots are extremely well-trained, including simulator tests of everything that might go wrong. They have written procedures of how to do it right, and written procedures of what to do if something goes wrong. They know if they make a serious enough mistake, everyone on the plane will die.

So how can they still make simple mistakes? It's familiarity breeds contempt, just like walking around the site or moving material. You do it ten thousand times successfully, you drop your guard, and bang! something goes wrong.

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