Minutes of 14th FFIR meeting on 8/24/2000

The meeting was held in a room of 3-425 at KEK, 13:30-14:30, 8/24/2000. We discussed on (1)brief report from 3rd ACFA-LC workshop, (2) FFTB-2 collaboration and (3) "minimum" field gradient of superconducting QC1.

(1) Brief report from the 3rd ACFA-LC workshop The 3rd ACFA-LC workshop was held on 8/9-11,2000, Taipei,( 8/9-10 at Academia Sinica and 8/11 at National Taiwan University whose one day was dedicated to the ACFA working group). At the dedicated day 8/11, there were activity reports from Europe(TESLA) and North America(NLC), and also activity-reports from physics (Higgs, SUSY and QCD) and detector(3T detector model/calorimeter, CCD-VTX, CTC, MDC, Pair Monitor and FFIR) subgroups, and two talks on PLC- and e-e- options. The transparencies(pdf) are available here. I reported our recent activities since the 2nd ACFA-LC workshop. My proceedings paper will be available at the ACFA-IR home page. The working group goal in this year(until March 2001) is to write a report to ACFA.

(2)FFTB-2 As reported at the last FFIR meeting, we will discuss on a possibility of FFTB-2 international collaboration at LCWS2000, 10/24-28, FNAL Chicago. The contact persons are Nick Walker(DESY), Daniel Schlute(CERN), Tom Markiewicz(SLAC), Tauchi(KEK), and P.Burrows (Oxford univ., UK) will chair the discussion. The major interest is (a)Raimondi's new FF optics, (b) vibration issues, (c)Shintake laser monitor, (d)collimator material and (e)beam halo measurement etc. The FFTB-facility(SLAC) will disappear until 2003 without proposal. How should we contribute in this collaboration from Asian aide? In our discussion, there was a proposal of FFTB at ATF since the ATF has smaller emittance than SLAC's FFTB, that is, we may get 30nm beam at FFTB/ATF rather than 40nm at FFTB/SLAC. Oide-san has designed the final focus system at ATF a long time ago. So, it is very natural put in the second phase of ATF as ATF-2. The conclusion was to form a working group to consider this possibility as soon as possible.

(3)"minimum" field gradient of superconducting QC1 Although Tsuchiya-san could not attend this meeting, he asked Miyamoto-san to inquire a question that "What is the minimum field gradient of superconducting final focus quadrupole magnet (SQC1)?" here. The answer may not be strictly given. However, we list possibilities as follows;

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ĦĦĦĦl* (m)   gradient  (T/m)  length (m)  comment
     2.5      117              3.5       the value in the JLC-1
     4.0       56              4.4       Raimondi's optics & scaling
     2.0      224              2.2       the  nominal value of JLC-DS
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There seems to be wide range in the gradient for the optimization among l*, gradient, length and choice of optics. In general, from an experimental side in terms of background, the lower gradient is more preferable since QC has the larger aperture and less collimation depth etc. Therefore, SQC with large aperture may be the best option.

The next meeting will be on 13 September (Wednesday), 2000 13:30 - 15:30 at 3 gokan, 425.