Minutes of 20th FFIR meeting on 12/13/2000

The meeting was held in a room of 3-425 at KEK, 13:30-14:30, 12/13/2000. We have (1) a report of GM2000 workshop by N. Yamamoto and (2) present status of support tube prototype R&D by H.Yamaoka.

(1) GM2000 workshop (transparencies, 9 pages, pdf ,630kB ) Yamamoto reported the GM2000 workshop . Total number of participants was 58 from 20 different laboratories in the world. From Asia, Toshiharu Nakazato and Schin Date, both of whom are Spring8, Japan, participated together with Noboru Yamamoto (KEK). The ground motion becomes a common concern for photon factories (Spring-8, ESRF ), gravitation wave facilities (LIGO) and high energy detector system (ATLAS) as well as linear colliders. So, there were many interesting talks from them. For details, please visit the web site of GM2000-talks . Especially, Ralph Assman's talk is a very good overview on "GM&V problems in Linear Colliders". One of topics was LEP measurements for 10 years and SLAC-tunnel measurements for 17 years to clearly show a systematic ground motion dominating the diffusive one as ATL-law. In discussion on the ATL, poor measurements on L were pointed out while the T-part was well measured. In the workshop summary, following future plans on ground motions for linear colliders were listed; (a)ground motion and vibration studies in SLD, (b)vibration stabilization R&D, (c) SLAC-UBC vibration stabilization R&D, (d)SLAC-FNAL-Budker INP slow motion studies in FNAL MI tunnel, SLAC PEP-II tunnel and Aurora mine, (e)cultural noise versus depth studies in FNAL NUMI tunnel, (f) FNAL-SLAC studies of SC quad magnetic center motion and (g) LEP motion data analysis will continue. For (a) and (d) specifically, KEK was asked for collaborations. (a) will use two colliding beams with a new FF optics a la Pantaleo Raimondi. At KEK, we have been investigating on a possibility of FFTB (final focus test beam) at ATF for similar purposes except for two beams. So, we might be difficult to contribute in (a) project as former FFTB/SLAC collaboration. For (d), they are very interested in a half-filled hydro- tiltmeter for slow motion measurements, which has been developed by S.Takeda at KEK. We continue to discuss such opportunities.

(2) Present status of support tube prototype R&D H.Yamaoka explained the present status. He just started to take data with oscillators. There are two independent devices to measure vibrations of the prototype. One is a laser system and the second one is a geophone. Output signals shall be examined by Fourier analysis. At present, there is a problem in the gain-calibration constant. Anyway, this was the first trial, so nothing is serious. Useful suggestions were provided.

(3) ACFA report We will put the first version on a web soon, which is based on a chapter in the JLC Design Study, KEK-Report 1997-1, April 1997. Our strategy is to update it adding new studies since then such as new FF optics, veto system and pair monitor etc. .

The next meeting will be on 24 January (Wed.), 2001 13:30 - 15:30 at 3 gokan, 425.