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Matter in Extreme Conditions Instrument on Track for Early 2011 Construction Start

Hae Ja Lee and Richard Boyce, in Hutch 6, show off a diagram of the MEC instrument. (Photo by Julie Karceski.)

The Linac Coherent Light Source's sixth scientific instrument, the Matter in Extreme Conditions instrument, is blitzing through the project planning and approval stages. Project Manager Richard Boyce and Instrument Scientist Hae Ja Lee hosted a successful review of the Department of Energy milestone Critical Decision 1 in January, and received final approval on March 1. With CD-1, the project's preliminary budget and design plans are now approved, and Boyce and Lee are working hard to obtain approvals to start construction by early next year.

"We've hit the starting line running," Boyce said. "We're moving very fast."

Now within sight are CD-2, which is approval of baseline design, and CD-3, approval to begin construction. To provide this instrument to scientific users as soon as possible, the project is combining CDs 2 and 3 into one review, hoping to have these approvals finished by the end of 2010. That way, construction could be underway by January of 2011. Commissioning of the completed MEC instrument is expected to begin in mid- to late 2012.

In addition, the project can get a head start on limited construction. The SLAC federal project director, Hannibal Joma, can approve early installation when the team is ready.

Right now, the project team is working on plans to install a mirror along the LCLS X-ray beamline that will deflect the beam horizontally through Experimental Hutches 4 and 5 in the Far Experimental Hall and into Hutch 6, where the MEC instrument will reside. In addition, they are working to procure the vacuum beam transport that will deliver the high-energy LCLS beam to the MECi.

The MEC instrument, or MECi, will use LCLS's ultrabright X-rays together with other laser beams to reveal how different materials respond to extreme temperatures, pressures and densities. Through such studies, scientists can begin to gauge how matter might exist under similar conditions in a supernova or within a planet's core.

"The uniqueness of the MECi is the combination of the LCLS free-electron laser beam and high power lasers," Lee said. "It's tailored to accomplish physics under extreme conditions."

On March 23–24, SLAC hosted a review of the MEC instrument sample diagnostics—inviting in a team of experts from both the university and government lab communities to evaluate the MECi design. At the review, Lee presented the details of the MECi optics, which will define the LCLS X-ray beam, and the diagnostics, which will probe conditions inside the instrument, for discussion and feedback. The review team spent two days in a Kavli conference room, scrutinizing the proposed details of the MECi.

The MECi diagnostics will provide physicists with data such as the temperature and density of the electrons in the matter and the LCLS beam itself. They can also inform scientists about the electron energy levels in the mater.

The MEC instrument also includes two laser systems—one providing a short pulse (≥100 mJ per pulse at 800 nm, ≤ 40 fs) and the other, a long pulse (≥ 50J per pulse at 527 nm, 2-20 ns). These lasers' primary function is to create extreme states of matter that are well defined. By tailoring the pulse duration of the long pulse laser system, for example, matter can be driven to extreme pressures without melting. In general, when combined with the LCLS X-rays, these beams will create and probe extreme states of matter or as Lee put it, "push the material over the limit."

Similar science is presently carried out at large laser facilities worldwide. What makes the MEC instrument unique is the ultrabright X-ray source, the LCLS. MECi will be the only instrument capable of mapping out, in exquisite detail, the complexities associated with these highly excited states of matter.

"Many facilities use lasers to strike materials," Boyce said. "What's unique here is we're combining lasers with the LCLS beam."

—Julie Karceski
SLAC Today, April 12, 2010