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In this issue:
Bringing Power to the International Linear Collider 
Public Lecture Tuesday: Journey to the Center of the Earth—Exploring High Pressure
SLAC Green Note: $$ For Making Energy Improvements to Your Home

SLAC Today

Thursday - September 24, 2009

Bringing Power to the
International Linear Collider 

Accelerator physicists Chris Adolphsen and Chris Nantista with a diagram of the coaxial tap off.
(Photo by Nicholas Bock)

Measuring in at more than 30 kilometers, the proposed International Linear Collider would be the longest particle accelerator ever built, providing physicists a better view of subatomic world than ever before achieved.

But becoming the biggest isn't easy. The ILC's unprecedented scale presents plenty of challenges, and more than 200 labs and institutions around the world are collaborating to make it work. At SLAC, accelerator physicists Chris Adolphsen and Chris Nantista are working on one point that has proven to be particularly prickly: figuring out how to provide the accelerator with the power needed to drive the machine's high-energy particle collisions.

At most linear accelerators, this power is provided by klystrons—devices that generate radio frequency waves to propel charged particles from one end of an accelerator cavity to the other. Klystron technology itself is nothing new. It has been around for nearly 70 years, and used in particle accelerators for almost as long. In the meantime, labs around the world have come up with no shortage of methods for coupling klystrons to accelerators. Expanding any one of these models to the ILC scale, though, presents a unique challenge.

One of the biggest concerns is cost. The current ILC plans call for two parallel tunnels—one for the accelerator cavity and associated cryogenics, the other for the klystrons and their power modulators. The biggest selling point for the two-tunnel approach is reliability. Technicians would be able to access the klystrons even during accelerator operation, ensuring that any problems that might arise could be fixed without having to shut the whole machine down. But digging one 30 kilometer tunnel 100 meters underground would be pricey on its own. Digging two would be considerably more expensive.

"The goal here is to explore different options for bringing the cost down," said SLAC accelerator physicist Chris Nantista. "One idea for doing this is to revisit this idea of two tunnels and see if we can't go to one."  Read more...

(Image - public lecture poster)
(Poster: SLAC InfoMedia Solutions.)

Public Lecture Tuesday: Journey to the Center of the Earth—Exploring High Pressure

Next Tuesday, September 29, SLAC and Stanford researcher Wendy Mao will present a public lecture, "Journey to the Center of the Earth—Exploring High Pressure."

At the pressures found within the center of the Earth, minerals do not simply compress. Pressure dramatically alters all materials properties, in the process creating numerous new phases of matter not found on the surface. Mao's lecture will describe how researchers simulate the conditions found in planetary interiors in the lab, what kinds of new behavior they find, and how these observations can explain what is going on within the Earth. High pressure explorations also lead to discoveries of novel materials with potential for practical applications.

Mao's talk will take place at 7:30 in Panofsky Auditorium, to be followed by refreshments and a chance for questions in the breezeway. The event is free and open to all.

(Image - ISEMS leaves)

SLAC Green Note: $$ For Making Energy Improvements to Your Home

It is not too late to take advantage of 2009 rebates and federal tax credits for making energy efficient improvements to your home. For information on currently available special offers and rebates on energy efficient products in your area, go to Special Offers and Rebates from ENERGY STAR Partners.

Federal tax credits are also available for a variety of home improvements such as insulation, windows and doors, roofing, HVAC, and solar energy systems. See Federal Tax Credits for Energy Efficiency for specific details.


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