1) Results from Sasha Drozhdin on additional masking of crab cavity
2) Report from Cherrill Spencer on the visit to IHEP


Sasha made updated studies of masking of the crab cavity. With respect to previous studies (see notes from BDS meeting on September 27, 2005) additional mask in front of the crab cavity was introduced. It is shown that this mask can block all the SR photons so that no photons would hit the cavity or the antenna of the low order modes coupler (which tip is at 11mm from the cavity axis). The photon distribution is also primarily in horizontal plane, so it would help if the coupler can be placed in vertical plane. From these studies, it appears that redesign of the coupler, to move it further out from the axis, is not necessary or at least not as essential as thought before.


Cherrill presented summary report from her very useful and fruitful visit to IHEP, where production of ATF2 quads is taking place.
    During this trip (December 6-14, 2005), Cherrill observed completion of main and trim coil winding forms; observed and inspected coil winding shop; inspected first 4 wound trim coils; observed and inspected coil potting shop; observed the brand new Electric Discharge Machine (EDM); inspected 4 quadrants of the first quadís steel core (before EDMíing of the hyperbolic-shaped poletips); etc.
    During the weekend of this period, assembled coreís 4 poletips were machined and then measured. All toleranced dimensions were found to be within acceptable limits.
    As a next step, the first core will be measured again on a CMM. The hollow conductor should arrive today (20th Dec), then five main coils will be wound and potted. The first coil will be cut in half and inspected for the turnís pattern and quality of impregnation of the epoxy. If the first coil will be OK, then will continue to wind other coils. By ~ 9th January - first magnet will be assembled. By ~ 25th January first magnet will be measured at IHEP by new, custom designed rotating coil. If the first quad looks OK, then production will be given go-ahead.

Andrei Seryi, 12/20/05