Minutes of 38th FFIR meeting on 4/25/2002

The meeting was held in a room of 3-325 at KEK, 13:30-14:30, 4/25/2002. We discussed on R&D plan in this fiscal year and activities on the beam delivery system.

(1) R&D Plan

We continue to study on the support tube(prototype). First, we are going to investigate an effect of the central part of the tube in comparison with the case of cantilever system in order to determine the support system, i.e. a tube or two cantilevers. Since the mask must be assembled by several pieces, its rigidness shall be recovered by some ingenuity. So the mechanical structure of joint sections will be manufactured by way of trial. The vibration isolation system will be also studied especially at a frequency range of more than 10Hz.

We will participate in measurement of ground motion at KEK and also in a R&D on an active feedback system collaborating with a JLC accelerator group and KEK-machine shop.

We have requested a budget for the above plans.

(2) Recent activities

As we discussed at the previous meeting, a new group of beam-detector(BD) simulation study has been made for machine-related background studies at the BDS (from an exit of the main linac to the beam dump). The home page is available here.

For the simulation, the configurations of magnets are necessary at the BDS. S. Kuroda, who has been investigating the final focus system at the ATF-2, joined us in order to provide the optics of collimation and final focus system collaborating with N.Yamamoto.

The magnet configuration at the dump line is available up to the second focus point (about 70m from IP, see a web site of http://acfahep.kek.jp/subg/ir/bds/jlc-bds.html#dump ).

For a detailed geometry at IP, beam instrumentation devices must be identified. Among them, a fast feedback system is the most complex. So, T. Tauchi will prepare the first version.

The next meeting will be on 16 May (Thu.), 2001 13:30 - 15:00 at 3 gokan, 425.