Dear all, I am sending out the minute of the last FAT meeting, held yesterday. Best regards, Stefano MINUTES OF THE FAT MEETING, 7 october 2002 ------------------------------------------ Chairman/Secretary: S. Redaelli Present: HB, RA, FZ, MK, SR * The workshop Nanobeam2002 was held in Lausanne from 2 to 6 September 2002. The chairmen RA and FZ will give a summary of the workshop next Thursday, 11 October, at 11am in the PS conference room. People of SL-AP are encouraged to come. To allow people to attend this seminar, the SL-AP Group meeting will be exceptionally anticipated at 10am. * Draft design of a compact final focus at CTF3. FZ showed a preliminary design of a final focus test facility that could use the CTF3 drive beam to test the Raimondi-type FF. This final focus test stand would be about 10 m long and could easily be installed in the CTF3 area (different possible locations are available). The draft design needs 16 quadrupoles, 2 dipoles and 4 sextupole. According to H. Braun and R. Corsini, the following beam parameter could be achieved: Energy -> 200-400 MeV Trans. Norm. Emittance -> 1 - 4 micrometer Bunch length -> 300 micrometer Energy spread -> 0.1 - 0.35 % Bunch population -> 6 - 30 x 10^9 The design beta functions at the IP are 50mm x 0.1mm (horiz X vert) and would allow one to obtain a vertical beam size of 500 nm (case of 1 micron normalized emittance and 0.1% energy spread). FZ also gave a recipe he has used to design the FF optics, according to the approach of S. Kuroda from KEK. More details will be included in the Nanobeam2002 proceeding that FZ is writing. * Effect on luminosity of solenoidal field from detector and crab cavities. FZ has presented some calculation he did to quantify the effect of the solenoidal field on the beam position and size at the IP. For any incoming beam angle, the kick from the fringe field (in hard-edge approximation) cancels exactly the effect of the circular motion inside the solenoidal field, resulting in zero beam offset at the center of the solenoid. Therefore, the solenoid should induce no beam offset at the IP for linear collider with a crossing angle. However, the luminosity can be reduced considerably by a fast relative vertical motion of the two colliding beams during the collision. The complete calculations of these effects will be published in the Nanobeam2002 proceedings. * HB reported on the Geant4 Workshop, held last week at CERN. HB gave a presentation about the implementation in Geant4 of the muon production (plenary section on e.m. processes). HB pointed out that the Geant4 community is very broad, and this program is being tested from very low up to very high energy. LHC and CLIC should take profit from the collaboration with this community. Though the program is still under development, Geant4 has proven to feature considerable improvements with respect to Geant3, in particular for the implementation of the muon background production. HB will be involved in the implementation of production of secondary mouns from the e+e- annihilation. This phenomenon could be relevant for high energy machines like CLIC. -- Stefano Redaelli office: CERN Meyrin 112-4-C25 email: Stefano.Redaelli@cern.ch tel: 00 41 (0)22 767 89 37 CERN - SL Division fax: 00 41 (0)22 783 05 52 CH-1211 Geneva 23 (CH) private: 00 41 (0)79 563 32 83