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"Extraction Line Energy Spectrometer"

The physics program of the ILC demands a precise knowledge of the center-of-mass collision scale. One ingredient to achieve this is a real-time absolute measurement of the colliding beam energies at the 100 ppm level of precision and accuracy. This project is intended to design and demonstrate the feasibility of an energy spectrometer in the ILC extraction line which can achieve this goal. This work is equally applicable to all detector concepts, and is actively working on designs for all foreseen IR designs.

This work is primarily being done at the University of Oregon by Eric Torrence, although close collaboration has also been ongoing with SLAC related to detector tests in End Station A.

This work has been proceeding on two fronts. First, simulation work at Oregon has been ongoing to understand the operational parameters and environment in the extraction line. A realistic beamline simulation based on BDSIM is currently under development. Second, work on detector development has been ongoing for several years using Cherenkov radiation in Quartz fibers to detect secondary electrons from the hard syncrotron radiation produced in the spectrometer magnets. A first prototype has already been built at SLAC and will see its first beam time at SLAC in Fall 2005.

Over the coming year, we intend to finish first studies of the extraction line environment with a complete Geant4 simulation of the beamline and XLS detectors. We also will take first data with the prototype device and validate the Geant4 prediction of the expected signal rate.

On a longer term timescale, we expect to build a full-blown prototype spectrometer in coordination with the upstream BPM-style device in SLAC ESA. The timing of this project depends upon funds available and the results of the first round of beam tests. A second prototype detector which would be suitable for this test is currently in the design phase.
Please address the following questions in your statement.

  • What are the goals of this R&D project. How does this R&D project address the needs of one or more of the detector concepts?

  • If there are multiple institutions participating in this project, please describe the distribution of responsibilities.

  • Are there significant recent results?

  • What are the plans for the near future(about 1 year)? What are the plans on a time scale of 2 to 3 years?

  • Are there critical items that must be addressed before significant results can be obtained from this project?

  • Is the support for this project sufficient? Are there significant improvements that could be made with additional support?