Evolving the ILC baseline

Barry Barish, director of the ILC Global Design Effort, wrote this column.

Over the past year, the ILC project managers have led a focussed effort to assess the ILC baseline configuration that is documented in the Reference Design Report (RDR) and as a result have developed a set of proposed baseline changes that are aimed at reducing costs and improve the technical design. The SB2009 Proposal Document outlines a set of proposed changes, includes descriptions of each change, as well as some discussion of the pros and cons. The first step in evaluating this proposal was a review last week in Oxford, UK, by our Accelerator Advisory Panel (AAP), an internal committee that advises me on technical and management issues. I will discuss the AAP recommendations in a forthcoming column, once they deliver their report to me. Today, I address some of the general features of the proposal.

To a large extent the original motivation for this study was to find major cost savings relative to the RDR. As stated in the proposal document, "The adopted approach to re–baselining is based on an assumption that the RDR design – although sound – is both conservative in many of its design decisions, relatively immature from a detailed engineering standpoint, and is "performance–driven" as opposed to cost optimised."

But, a key result of this study is that, even if we adopt all of SB2009, it would result in cost savings of only 10–15 percent, and these changes could even introduce some associated performance degradation and some areas of increased technical risks. We can immediately draw as a very important conclusion of this intensive one–year study the observation that the RDR is already close to being a cost–to–performance optimised design. Therefore, we should be very selective and only adopt changes that on balance improve performance, reduce risks, make a better overall design or make cost savings without significantly degrading the other factors.

Topological diagram of the proposed changes in the ILC central area, a much more coherent integration of this very complex central region containing the sources, damping rings, beam delivery systems, detectors, etc.

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-- Barry Barish

New bimonthly publication from Fermi Natural Areas

Fermi Natural Areas, an environmental science program of FRA, recently published its inaugural newsletter. The group will publish the newsletter bimonthly. The mission of Fermi Natural Areas is to restore, manage and conserve Fermilab's natural areas in support of the laboratory's science mission, and to encourage Fermilab's neighbors to experience and enjoy Fermilab's natural beauty. The newsletter highlights upcoming and past events, environmental and wildlife updates from sightings and events on site and beautiful images of Fermilab's natural scenery.

View the newsletter here.

Supernova winds blow galaxies into shape

From ScienceNews, Jan. 13, 2010

After years of struggling to understand how to properly assemble a galaxy, astronomers have discovered that the answer is blowin' in the wind. The supernova wind, that is.

New computer simulations show that winds generated by supernovas, which are the explosions of massive stars, can push stars out from the center of a dwarf galaxy. This simulation of supernova winds redistributes both ordinary matter and invisible dark matter in a way that almost perfectly matches observations of the way matter is distributed in actual dwarf galaxies. Fabio Governato of the University of Washington in Seattle and his colleagues describe their simulations in the Jan. 14 Nature.

Previous attempts to model galaxy formation based on the highly successful theory of cold dark matter - which states that invisible material must account for 85 percent of the mass of the universe - have done "an awesome job" of explaining such global properties as where, when and how many galaxies should form, notes Governato. But the models have failed to reproduce some of the key features of individual galaxies.

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