Agenda and Summary:
1) General discussion of plan of work after Snowmass.
2) BSY chicane, M.Woodley
General discussion of plan of work after Snowmass:
The group discuss general directions and priorities of the design work after Snowmass, including design of IR with intermediate crossing angle (10-12mrad), which will be considered for 3.5m and 4.5m L* as soon as magnet design will be evaluated in sufficient details to determine the extraction L* and apertures. The extraction optics will be then redesigned and Geant model of IR, for background calculations, created. The group also discussed other issues that require attention and design improvements: such as design of tune-up extraction (see below); the need to continue design of beam dump, where the beam painting will be included, and the need to evaluate the DPA (displacement per atom) in the window; the need to improve collimation optics to make the IP beam divergence decrease for off energy beam, which would allow achieving collimation performance as good as in NLC optics (see link to a file on the left, slide 8); the need to advance FD design of ATF2 and possibly to look into a possibility to use and test tail-folding octupoles at ATF2, etc.
BSY chicane :
Mark considered design of chicane in BSY which would serve several purposes: detection of the off-energy bunches and abort triggering, providing a place for laser-wire signal detection, measurements of beam energy spread. A tentative design was shown. There are questions which need to be studied further, such as the method of detection of bunches with betatron errors (presumably with help of the upstream diagnostics & skew correction section) and the number of bunches that may go through; the number of bunches that can damage the energy spoiler; realistic field and rise time of kickers; etc.
Andrei Seryi, 09/06/05