Date May 4, 2000
Attendees M. Doleans, J. Galambos, J. Holmes, D. Jeon, S. Kim,  J. Wei
 
J. Wei reviewed the APS meeting held at Long Beach. Invited talk subjects 
were discussed. There will be 4 talks each on single and multi particle 
dynamics. The emphasis is on experimental work. SNS will have several 
invited talks, including speakers D. Moncton, N. Catalan Lasheras, M. 
Blaskiewicz, C. Rode, J. Stovall and R. Sundelin. Private discussions with T. 
Wangler and I. Hoffman indicate that the equipartitioning in the linac
should not be a serious problem. 

Abstracts for Linac 2000 are submitted by S. Kim on cavity design and 
J. Stovall et. al. for the SC linacs design. S. Kim, D. Jeom, J. Wei ,
J. Galambos and S. Aleksandrov should plan to attend.

Abstracts fro EPAC 2000 are submitted by J. Holmes ( space charge modeling 
in PSR), J. Galambos (parallel computing with ORBIT), and D. Jeon 
(paramteric resonances and preliminary multiparticle dynamics in the SC linac).
No RHIC papers are being presented. A discussion of the RHIC commissioning 
indicated the problems associated with shorcuts taken due to reduced funding.

S. Kim gave a presentation on the SC cavity work. There are several approximations 
for the coupling constatnt, what result in ~ 10% difference in coupling. Sang ho
is computing the coupling with a numerical model to verify the approximations. 
Lorentz force detuning is also being calculated. It is important to use 
the average force when calculating the detuning - use of the peak force
results in an overestimate of the detuning. The detuning calculation
is seperated into fixed boundary and free boundary parts. The free boundary
part is difficult to calculate properly. But estimates on its realtive magnitude
can be made by comparison to TTF measurements and calculations. For the beta_g
= 0.61 cavity, a K = 3 Hz/(MV/m)^2 is predicted using peak forces. Cavity optimization 
is also started for the beta_g = 0.81 case. For this cavity, the  
K = 1.6 Hz/(MV/m)^2 with stiffeners and the E_peak/E_0 = 1.65 for the interior
cell. Preliminary multi-cell analysis by Marc Doleans indicates the importance
of a maintaining a fine enough mesh size while evaluating field flattness. Use of a 
finner mesh apears to change the field flattness from the reference 1% level
to ~ 10%. This effect is being checked, and will be forwarded to JLab.

J. Galambos will apply for computer requsition initiation privlege, and purchase
a set of PCs for the group.

D. Jeon will contact R. Ryne's group about their APS work and initiating
a benchmark between ther code and Parmila.

Slava was a BNL the previous week, and had useful discussions. The issues raised
were (1) impedance of the foil holder mechanism, (2) the foil electron 
collecter and the influence of the beam potential on secondary electron
trajectories near it, and (3) the impenace of the extraction kicker and the
influence of the mu value. There is a question of whether lowering the
mu would introduce other instabilities.