Accelerator Physics Group Meeting 04/12/2001

Attendance: S. Alexandrov, S. Assadi, P. Chu, S. Cousineau, S. Danilov, 
            M. Doleans, J. Galambos, J. Holmes, D. Jeon, S. Kim, T. Shea, 
            W. Wan, J. Wei


General issues and information:

The SNS parameter list is of immediate concern.  Group members should 
   go over the sections of the list covering the areas for which they are 
   responsible.  This is a high priority exercise.  Eventually we need to 
   produce a design manual, which may be bootstrapped from the parameter 
   list.

Group memebers with interests in beam dynamics (space charge and 
   instabilities) are encouraged to visit Ingo Hoffman at BNL during the 
   next couple of months.

The RF power budget overhead is high priority.  Sang-Ho Kim should visit 
   LANL for discussions.

An end-to-end simulation with the new machine parameters should be 
   completed for the DOE review.  The linac is the critical portion of 
   this because the major machine changes since the last en-to-end have 
   been in the linac.  Dong-o Jeon and Eugene Tanke will be involved in 
   this work.


Individual reports:

Saeed Assadi has found and corrected numerous inconsistencies concerning 
   the machine diagnostics in the parameter list.

The ring working point has been listed as (Qx,Qy) = (6.4,6.3) for the 
   parameter list.  The backup candidate of (Qx,Qy) = (6.23,6.20) remains 
   in consideration pending further study.  Jeff Holmes will contact 
   Yannis Papaphilippou regarding sextupole resonance correction for the
   (6.4,6.3) working point.  We also need to calculate stopband widths 
   for the half integer resonance at 6.0 and for the sextupole resonance.

Sasha Alexandrov used MATLAB to time readings of the BPMs set up by 
   Earnest Williams, and found that it requires 50 ms to acquire data, 
   regardless of whether one or several signals is accessed.  This led to 
   a discussion by Tom Shea stressing the need to understand the data 
   requirements of the applications and AP people.

Mark Doleans and Sang-Ho Kim evaluated the transverse kick to the beam 
   from the fundamental power coupler and found it to be 10 microradians 
   per cavity, which is small.

Weishi Wan has finished the global coordinates for the transfer lines, and 
   will next consider the ring.  LANL still needs to supply the linac data.  
   Dong-o has input files for the current DTL lattice.

Paul Chu has been working on a cdev model server design.  Tom Shea discussed 
   the option of using new load-balancing messaging servers.