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In this issue:
From the Director: Ray Orbach's visit to SLAC
Getting in Under the Ground Floor
Word of the Week: Diffraction
Building the LCLS: Weekly Update

SLAC Today

Friday - May 30, 2008

From the Director: Ray Orbach's visit to SLAC

(Photo - Persis Drell)

Ray Orbach visited SLAC this week in what will probably be his last official visit to the Laboratory as Undersecretary for Science in the Department of Energy. Ray's most recent visit before this came at the time of the Linac Coherent Light Source (LCLS) groundbreaking, so yesterday was a wonderful opportunity for him to see the tremendous progress in LCLS construction. He also made his first visit to the Kavli Building and was able to interact with some of the scientists at the lab.

This was also an opportunity for us to thank him for his dedicated service over the past six years. Ray was sworn in as the Director of the Office of Science on March 14, 2002, two weeks before I started working at SLAC. I have not known an Office of Science without Ray at the helm.

In his tenure as Director of the Office of Science and Undersecretary for Science, Ray has been a fierce advocate for the physical sciences. Ray has been a vocal champion of the critically important role that DOE plays in supporting the physical sciences. The national profile of the physical sciences, and the recognition of their importance to society, are much more widely appreciated now than they were six years ago, thanks in part to the energy of Ray's advocacy.  Read more...

Getting in Under the Ground Floor

A worker distributes concrete pumped through a hose to form the monolithic slab floor in the Far Experimental Hall.

What do you get when you combine 120 concrete trucks filled with more than 1,000 cubic yards of concrete, with 350,000 pounds of steel rebar? "Happy physicists," according to Linac Coherent Light Source (LCLS) Conventional Facilities Manager David Saenz.

Yesterday morning, starting at sunrise, scores of concrete trucks rumbled onto the SLAC site to complete what is the last major pour for the LCLS civil construction. The trucks lined up throughout the day at the entrance to the access tunnel behind the Collider Hall to deliver 1,000 cubic yards of concrete to form a single slab floor for the Far Experimental Hall deep beneath SLAC's east hills.

Pouring the massive floor as a single slab will give physicists an added degree of flexibility in reconfiguring experimental hutches in the future. Had the floor been poured in sections, the joints between the sections would allow the floor to shift and move in ways that could wreak havoc on the delicate alignment of the LCLS hardware.

In the two days alone leading up to the pour, working round the clock, crews put over 190,000 pounds of steel rebar in place to form the rigid skeleton for the slab floor. The crews then spent Thursday delivering concrete through long hoses down the access tunnel, a process that took over 18 hours.

Word of the Week:

Diffraction is a phenomenon that applies to any kind of wave, whether sound or water or light, in which the waves interact with obstacles in their path. Light waves diffract when they are made to interact and bend around objects they encounter—the faint rainbow pattern on the underside of a CD, for instance, is the effect of light striking very tiny dimples on a foil surface, with different colors diffracting off at different angles. X-ray diffraction is a technique used at the Stanford Synchrotron Radiation Laboratory (SSRL) and other synchrotron labs to determine the structure of molecules by shining a needle thin beam of X-rays onto a sample, causing the X-rays to interact with atoms within the sample and form a readable pattern on a detector.


Building the LCLS: Weekly Update

Construction highlights from the Linac Coherent Light Source (LCLS) this week include:

- Pouring the concrete floor slab inside the Far Experimental Hall.

- Forming the concrete curbs surrounding the parking areas adjacent to the Near Experimental Hall and Central Utilities Plant.

- Installing lighting and stairs to support Building 913 atop the Beam Transport Hall in the Research Yard.


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