Agenda:

1) Steve Smith -- Separation of signals in IP BPMs for 2-mrad IR
2) Andrei Seryi, Mark Woodley et all -- ATF2 optics developments
 

Summary:

Responding to a question posed at LCWS05, Steve Smith studied if the IP BPM can resolve a signal from the outgoing beam in spite of that the incomimg beam pass through the same BPM with several mm separation about 27ns earlier. The conclusion is positive: the directional stripline BPMs can provide required resolution and signal separation from the incoming beam. This is based on SLC experience and on conservative assumptions for the rejection factors due to directionality, temporal separation and phase relationships. 

Mark discussed ongoing studies of ATF2 optics with Turtle, SAD and Elegant. While the first two codes agree rather well, Elegant does not provide proper high order treatment of dipoles. Mark is also working on modification of the ATF extraction line diagnostics section, in order to provide truly orthogonal skew corrections.

Andrei discussed reduction of bend magnets in ATF2 final focus optics, and concluded that five bends can be eliminated. The remaining number of bends is 7 (4 in the diagnostics chicane and 3 in FF). The bends can be based on the same design. There is also ongoing work on reduction of the third order dispersion coming from the extraction line.

Andrei Seryi, 03/29/05