Takashi Maruyamai: Results
of photon reflection from the face of QF1 in small horizontal crossing angle
- The assumptions were: halo population of 1e-3, NLC BDS optics upstream
of IP, FD with L* =4.2 m downstream of IP, pole tip radius of QF1 is 7mm,
the VX radius and luminosity monitor radius are from NLC parameters.
- There is a direct view from QF1 to the vertex. However, in the
assumptions mentioned above, the number of reflected photons reaching the
vertex and converted to background is about 17/bunch, which is about 10% of
the total VX hits from other sources.
- Other potentially more important background sources are photo-neutron
production and disrupted beam loss due to the fringe field of QF1, that need
to be studied further, as well as the possibility to have downstream
diagnostics in this case.
Yuri Nosochkov: Options of the final quadruplet
Nosochkov presented several options of the final quadruplet (in similar way
as UK colleagues have done) or final triplet or penta-plet for head-on final
- The optics considered allow to squeeze the disrupted beam considerably,
making almost round beam (would this allow horizontal, rather than vertical,
- This optics can now be used to design final focus for the head-on IR.
- In the considered options the vertical beta-function was allowed to be
higher than in the FD case. Further work will include tests of SR effects in
this optics and also designing another options which would limit the
Andrei Seryi: Final Focus optics for a Crossing
- Andrei Seryi presented a version of optics for crossing angle IR, based
on NLC optics, where betatron collimation were modified to allow survivable
spoilers (in contrast to consumable in NLC case). The IP bandwidth of this
optics is good, the FD bandwidth may need further optimization. Collimation
performance studies can be started with this optics.