**(1) Neutron background estimations**
A. Miyamoto reviewed the neutron background estimations in order to verify
numbers in the draft. The most updated numbers have been presented at the
LC99 in October,1999 by him. However, numbers in the draft are those which have
been presented at LCWS99, May,1999 by Y.Sugimoto and some of them were wrong.
Correcting the latter numbers, there are still differences
as follows. The former is based on calculations by Fluka98, while the latter
is based on GEANT-3. The numbers are all at the VTX first layer (r=2.4cm), and
they are estimated for both beams.

---------------------------------------------- sources LCWS99 (GEANT3) LC99 (Fluka99) pairs 66 n/BX 252 n/BX 3x10^7n/cm^2/y 14x10^7n/cm^2/y BS photons 2x10^7/cm^2/y 5x10^7/cm^2/y where, 6x10^20n/y generated in total 1x10^17n/y back from water dump, which is located at 300m from IP. -----------------------------------------------

We also discussed on a further study on the dump line. In the present draft, future improvements were mentioned on the self-shielding effect and additional shield. At present, we can estimate the back-scattering rate of neutrons from magnets by looking at the same rate at QC1 for e+e- pairs. The beam loss positions must be very useful to see possible locations of the additional shields along the beam line. We would like to include these improvements in the report.

**(2) Present status**
N.Yamamoto identified a problem in the file of new FF optics. In matrix
elements for the second order cancellation, an element of (1,2)-component was
found to be non-zero which must be zero for the cancellation. He though that
this problem creates higher order (3rd) aberrations increasing beam sizes
at IP. He will try for the component to be zero.

**(3) Discussion: ACFA report**
All sections except for the pair monitor have been received and they are posted
on the web site of http://acfahep.kek.jp/subg/ir/group.only/acfarep/ .
Next step is to edit them for consistent contents.

The next meeting will be on 14 March (Wed.), 2001 13:30 - 15:00 at 3 gokan, 425.