1) Antisolenoids for SiD -- B.Parker,A.Seryi
2) 20mrad extraction line updates -- Y.Nosochkov
3) Background and beam loads in 2 mrad extraction -- T.Maruyama
Andrei and Brett presented layout of antisolenoids for SiD which are intended for compensation of the effects of the main solenoid on the beam size. The antisolenoids consist of four independent coils that allow fine adjustment of the field shape, magnitude and effective position. The cryostat for antisolenoids is about 1.7m long, and in radial direction everything is fit between r=158 and r=228mm. The force on the antisolenoid is about 15 tons. The antisolenoid can be anchored from the detector yoke. One of the questions, for further iterations of the design, is whether the inner radius of the return yoke cane be slightly increased to give more room for the antisolenoid and QD0.
Yuri presented an updated version of the 20 mrad extraction line. In this version the first extraction line quadrupole starts at the same position as the 1st quad in the incoming lines, the long quads are sliced in shorter quads, there is a free space for crab cavity on the incoming line, and the apertures are opened in the attempt to accommodate for the new IP parameter options. Tracking of the high statistics disrupted beams show no losses for the nominal case, several Watts of losses if the beams are offset in vertical, and several kW of losses for the high luminosity parameters and if the beams are offset. Studies of the longitudinal distribution of losses will be done as the next step.
Takashi have shown updated Geant simulation of 2mrad extraction line. Simulation shows that in the March 4 version of the extraction line, where the QEFX2 and QEFX3 quads are removed, the SR photons from the beam do not hit any more the SC quads. Effect from radiative Bhabhas was also estimated and found to give about half a Watt at first SC magnets. Evaluation of background due to these losses will be done next.
Andrei Seryi, 03/16/05