1) Update on IR Geant models and studies -- T.Maruyama
2) Wakes effects in ATF2 IP BPMs and kickers -- K.Bane
3) Large aperture SC sextupole for 2mrad -- V.Kashikhin
4) Diagnostics in 2mrad extraction line -- K.Moffeit
5) FF optics for 2mrad -- A.Seryi
6) Plans for ILC& ATF laser wire studies -- I.Agapov, M.Woodley
Takashi presented the work devoted to creation of more detailed and up-to-date Geant models of the IRs. One of the recent changes for SiD 20mrad IR is increase of vertex radius: the IP vacuum pipe ID is now 1.2cm with first layer of vertex at 1.4cm. The shape of Be chamber in IR was also changed, to provide stay-clear from the pairs. The high luminosity parameter case, however, cannot be accommodated -- pairs would hit the beampipe. This needs to be discussed with the parameters group. Details of QD0 SC quad, extraction quad and antisolenoid are being included into Geant model, for accurate prediction of the background and of the power deposition. Note that inner radius of QD0 vacuum chamber is 10mm, not 9mm as on the last slide of the talk.
Karl presented evaluation of wake fields in the low aperture kicker suggested for ATF2 during the January 2005 ATF2 workshop, and due to ATF2 IP nano-BPMs. In the kicker case, the orbit correction before the extraction has to be done rather fast, to prevent growth of the beam emittance due to geometrical and resistive wakes. In particular, the kick due to single pass through the 1mm kicker gap is about the same as the beam divergence, which means that the gap has to be increased. In the case of nano-BPMs, for the considered geometry the kick due to all 3 cavity segments, for the 3 nC and 1GeV bunch with 1 um offset is 15 nr. The needed stability of the IP beam angle and possibility to subtract the angle information from the measurements need to be evaluated.
Vladimir presented design of large aperture superconducting sextupole for 2mrad IR. The conclusion is that such sextupole, based on Rutherford cable technology, can be built with specified parameters (4.3Tesla at 95mm radius, which would be good enough for the 2mrad IR to go to 1TeV). Technology for such a magnet is quite mature.
Ken presented first thoughts of using the existing chicane to provide energy diagnostics in 2mrad IR. These considerations will continue.
Andrei presented a 2mrad FF optics which was re-matched using parameters of FD resulted from the 2mrad extraction line optimization.
Mark and Ilya discussed plans of laser wire diagnostics studies for ATF and ILC.
Andrei Seryi, 04/19/05