minutes ABP-LCE meeting 09.05.03

present: Td'A, WH, JJ, AK, EM, DS, FR, LV, FZ


action items
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LV has calculated the reduction of the effective collimator
impedance by suppressing the low-frequency lines. He obtained
a few percent improvement only. The small effect is due to the
inductive bypass as pointed out by E. Metral. Precise numbers
are available in a short note by Luc.

FR reports that Fritz Caspers has observed microwave 
transmission signals in the SPS and is now ready to monitor
the electron cloud.

EM followed up on last meeting. Calculation with 3564 bunches
instead 2808 gave a similar result (~20% difference). Two 
puzzles remain to be better understood, namely an enormous 
effect of the inductive bypass though no significant change 
in the plotted impedance, and difference between real and 
imaginary parts of the impedance. EM was PS supervisor last 
week.


PAC papers
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1 beam-beam paper by WH and Fred Jones, 2 papers on electron 
cloud (general overview and emittance growth), 1 paper on LHc 
upgrade with superbunches, 1 paper on resistive
wall for v<c, 1 paper on simulations of coupled bunch instabilities
due to resistive wall, ions, and electron cloud with application
to KEKB, 1 (controversial) paper on SPS impedance measurements
with 1 and 2 bunches.
 
Presentations of PAC/HALO03 highlights will be scheduled after
the conference/workshop. This could be a forum.


ZBASE
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Impedance database program for LHC and LEP, developed by O. Bruning.
TdA reports that the program is up and running again on lxplus 
and windows. He will primarily maintain the lxplus version. 


New LHC design report
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A new design report is due by September. LCE team should contribute
to chapter on beam-beam, collective effects, electron cloud, synchrotron
radiation. Detailed structure of the chapter and number of pages will
be discussed in smaller group later.


Visit by H. Tsutsui
-------------------

FZ informed the team that Hiroshi Tsutsui's bosses have given the
approval that he can visit CERN for one month this summer. H. Tsutsui
would contribute to the collimator impedance calculations.


Trip report
------------

FR reported from his FNAL visit. There was a concern about
electron cloud at he Roman pots. LCE team does not think this is
a serious issue, as electron cloud improves for smaller aperture.


Resistive wall instability
--------------------------

EM and AK discussed ongoing simulations of multibunch resistive
wall instability using a wake field approach. AK does not observe
the instability in the simulation so far.