Minutes of 82nd FFIR/BDSIM and 5th ILC-Asia WG4 meeting on 10/27/2004

The 5th meeting was held on Oct.27 10:00 am at rm.425 bldg no.3.

(1) Synchrotron radiation profile (Kuroda)
 (transparencies, pdf, 4 pages, 287KB)
       *  Mask size shold be less than 3.7 sigma_x / 19.0 sigma_y,
          otherwise SR light hits QD0 in opposite side.
       *  We might have serious problem in our treatment of non-linear term
          in magnetic field of sextupole.

(2) ATF2/optics (Kuroda)
     Comparison between GLC/NLC parameter and ATF2 parameter
(transparencies, pdf, 3 pages, 144KB)
       *  We have no parameter of ILC nor TESLA so far.
       *  ATF2 and GLC/NLC have the same order of chromaticity.
          Vertical local chromaticity at QD is
          -26,000 and -57,000 in ATF2 and GLC/NLC, respectively.
          Residual chromaticity is about 10% of that at SF.
       *  Design chromaticity at IP is 170 and 3 for ATF2 and GLC/NLC, respectively.
          This chromaticity does not make beam size at IP significantly larger.
       *  ATF2 should be a very nice facility to demonstrate local correction scheme.
       *  Vibration tolerance in ATF2 is almost same as that in GLC/NLC.
       *  We should ask TESLA people vibration tolerance in cold machine.
       *  We should study tolerance in field strength and position of magnets.

(3) Synchrotron radiation profile and ATF2/BPM (Tauchi)
  (a) Estimation of synchrotron radiation profile at QD
(transparencies, pdf, 6 pages, 1MB)
  (b) What shall we do with ATF2 beam?
(transparencies, pdf, 10 pages, 3.2MB)
       *  Set up cavity-typy nono-BPM and Shintake-monitor at IP.
       *  We will demonstrate compact FF optics and controlling beam orbit at nano meter level.
       *  In future, we will construct laser facility for photon linear collider
          to demonstrate collision between laser and ATF2-beam.
       *  Position of final doublet will be stabilized with active mover
          so as to make beam position at IP well controlled.
       *  Vibration of cavity type nano-BPM at IP will be monitored with  laser interferometer.
       *  To measure size and orbit of beam concurrently, Shintake-monitor and Nano-BPM will be set
          at IP and a few tens of cm away from IP, respectively.  Beam  size at Nano-BPM is ~um.
          We can measure beam orbit precise enough even if beam size is  ~um.
       *  Resolution of current Shintake monitor will be 60nm.
          We may need to use higher mode in laser cavity to measure 40nm beam size.
       *  One design of ATF2 Layout -> is it compatible with future XTF?
       *  Need to stabilize beam orbit within Nono-BPM dynamic range of  2-3um.
          Beam orbit stability is measured to be +/-5um (rms) in vertical direction.
          We have to study beam stabilization.

(4) Tilt of floor at ATF beam-line (Masuzawa)
(transparencies, pdf, 5 pages, 1.4MB)
     2.5days data
       *  Measurement starts at 10/22 21:30.
       *  Daily variation in tilt is less than 1 micro rad.
          ( cf. it is about 4 micro rad at Tskuba B4)
       *  No serious variation even after earthquake.

(5) ILC-WS program
       *  Conveners sent off e-mail to candidate spealers at 10/26 17:00.
       *  Takahashi-san will give a talk about gamma-gamma.

       * Propos FF facility (ATF2)
         We have to make its significance much more clear.

The next meeting will be on 2 November, 2004,10:00 - at 3 gokan, 425 .