Director's Corner

22 June 2005
Barry BarishToday, I want to briefly describe the process that led to choosing superconducting rf technology as the basis of the main linac technology for the global design effort. As I discussed last week, a decade of extensive R&D toward a linear collider demonstrated that it would be possible to build a linear collider using either room temperature copper structures or using superconducting rf cavities.

In order to evaluate these two choices, in February 2001, the International Committee on Future Accelerators (ICFA) requested the International Linear Collider Technical Review Committee to assess the current technical status of electron-positron linear collider designs in the various regions. This committee, made up of a group of accelerator experts working in the technical areas relevant to a linear collider, was chaired by Gregory Loew of SLAC. The committee's second report, issued in 2003, is a comprehensive analysis (526 pages) of the competing technologies. It identifies and classifies the issues for each in terms of risk levels, organizing them hierarchically. This analysis is very useful for anyone interested in the question, but it did not offer a basis of choice for the technology.

As a result, ICFA and the International Linear Collider Steering Committee created the International Technical Recommendation Panel to make a recommendation for the choice of technology, the. This panel, consisting of 12 members, four from each of the three regions, began work in January 2004.

Last August 2004, a crucial milestone was reached in making the choice of which technology to pursue for linear collider. The International Technology Recommendation Panel, which I chaired, submitted its recommendation to the International Linear Collider Steering Committeechaired by Maury Tigner and to its parent body, ICFA, chaired by Jonathan Dorfan. The recommendation read:

"We recommend that the linear collider be based on superconducting rf technology. This recommendation is made with the understanding that we are recommending a technology, not a design. We expect the final design to be developed by a team drawn from the combined warm and cold linear collider communities, taking full advantage of the experience and expertise of both." (from the ITRP Report Executive Summary)

We based our decision on a detailed analysis of the relative merits of the two technologies over a detailed list of criteria that addressed scientific, technical, cost, schedule and operability issues for each technology, as well as their wider impacts on the field and beyond. Next week, I will pick up on what followed this recommendation.

As for current developments, the European GDE is taking shape with the recent appointment of Brian Foster as the European Regional Director. I also am pleased to announce that Brian will be assisted by two Deputy Regional Directors, Jean-Pierre Delahaye of CERN and Nicholas Walker of DESY. Jean-Pierre and Nick will bring considerable accelerator physics strength to the European directorate, as well as providing direct connections to both CERN and DESY. In addition to strengthening the European GDE leadership, Nick and Jean-Pierre will play important roles in the GDE accelerator group that will be responsible for developing the global ILC design.