Accelerator Physics Group Meeting
March 8, 2001

Present: J. Wei, Slava Danilov, Jeff Holmes, San ho Kim, Dong O Jeon,  
Paul Chu, Mark Doleans, Eugene Tanke, Sarah Cousinea, Weishi Wan, 
John Galambos

Jie Wei noted that physics personel need to react carefully, and reach 
conclusions comphrehensively, and responsibly. Also publications author 
lists need to be inclusive, with credit given fully. Finally, it was noted 
that the DOE has not approved the idea of assume R&D success  vis-a-vis 
higher cavity gradients (due to EP)  for the baseline, due to the tight 
schedule. 

Danilov and Holmes presented benchmark results for the new impedance model 
in ORBIT. An analytically tractable model is used, and similar behavior is 
observed in the numerical results. A more exact beanchmark is underway. The 
model implies that halo may be generated from imedance enhanced beam 
oscillations.

Holmes reported that he working point search is still underway.

Cousineau reported good progress with Nuria Ctalan-Lasheas last week in 
incorporating collimation into ORBIT. 

Paul Chu noted that cdev communication with channel access  has been 
demonstrated and that a swig interface to cdev has also been implemented. 
This means that sripting interfaces through cdev should be possible, with 
the native scripting languages such as Tcl, python and PERL. 

Dong O reported that matching of the MEBT and DTL looks promising using  
emittance measurements on the D-plate, even in the presence of expected 
errors.

Weishi Wan reported that the survey team will be involved in the magnet 
measurement process and will record the magnetic center to fiducial 
information. We need to determine if the magnet measurement group uses the 
same centers as the survey group.

Sang ho reviewed the temperature rise calculations in the wave guide chase. 
Water cooling will be added to the wave guides as a result of these 
calculations. Questions remain as to the impact on reference line impact from 
the ~ 20 degree temperature swings expected in the air temperature.

Sasha reported on analysis of the BPM ability to detect the bunch length in 
the MEBT. Relative RMS bunch lengths should be fairly strightforward an 
independent of bunch shape. Absolute lengths require accurate knowledge of 
the bunch charge (i.e. current). 

Marc showed results of benchmarking SCL multi-particle tracking results and 
the impact of cavity misalignment. For expected cavity misalignments, with 
random distributions, there is little impact on the emittance.