Accelerator Physics Group Meeting

9/20/01

Present:J. Wei,  J. Galambos, S. Henderson, D. Jeon. S. Danilov, 
S. Aleksandrov, S. Kim, M. Doleans, S. Cousineau,D. Davino, M. Piva
S. Assadi

The meeting concentrated on the just finished ASAC meeting.
J. Wei reviewed the ASAC committee closeout session. Reliability is a 
concern, 90% is considered too optimistic for 2 years after start of 
operation. Power / reliability trade studdies should be done. 

The fronyt end is well enggineered and should be shipped as planned. However 
antenna lifetime and emittance blowup are a concern. It is hard to get 
good emittance at full current. The JARIE ion source should be considered 
(different technology). Also the front end diagnostic line should not be 
pursued. 

Regarding the linac, the basic physics design is complete, and  focus 
should shift to operation / upgrades. The multi-lab collaboration should 
continue through commissioning. Diagnostics requirements from end to end 
simulations should be tied into the commmissioning plan. There is no 
existance proof that the system will work, sans matching errors in the 
simulations. SNS should host a workshop onthe Lorentz detuning issue. 
There appears to be a good interaction between the physicists and 
diagnostic teams. The laser wire should be an R&D item.

The Ring recieved less attention - ASAC is pleased to see sextupoles inthe baseline, and hardware orders out. The physics team is responsive to ASAC.

J Wei lead a discussion on differnt options for MEBT improvements: 1) do nothing, 2) add collimation, 3) get rid of the MEBT chopper/ antichopper, 4) get rid of the anti-chopper, and use chopper for beam in gap cleaning, and 5) same as 4 but also chop the LEBT rise and fall.

D. Jeon will attempt to get Toutatis, and will investigate different MEBT scraping options. 

S. Danilov noted that Macek sees a new e-p  microburst phenomena at PSR, wherein the e collector signal rises and falls over several 10's of microseconds (to different magnitues). Also the addition of solenoids reduces the electron signal in the vicinity of the solenoid.