Date April 6, 2000
Attendees S. Danilov, M. DeLeons, J. Galambos, D. Jeon,  J.G. Wang, J. Wei
 

J. Wie discussed the upcoming JLab cavity workshop, reviewing the proposed 
agenda, JLab action items from the review, and JLab distributed information 
on cavity comparisons. It was noted that the HEBT phase advance per period 
is > 90 deg. The impact of reducing this to < 90 deg., and not keeping the 
HEBT line to second order achromat. Also a more uniform quad spacing may 
help.  D. Jeon will discuss this with D. Raparia.
There has been a concern on the compatibility and control of the engineer
drawings. After discussing with Cecil, Gary, Danny (ORNL) and Jac (BNL),
the AP group propose that:
1) Cecil maintains the master drawing of the project which includes not only a
  master version number but also origins and revision number of the components
  (e.g. ring rev. "V", Linac from LANL or Danny, etc.)
2) BNL's, Danny's and other's drawing become input insert to Cecil's drawing
  minimizing parallel drawing work from scratch and avoid mismatch
3) AP group works both at design level with engineers on component drawings,
  and also at master drawing level comparing final drawing with the original
  optics / design input
Later, Joe Error proposed to adopt the same coordinate system for all
components.


J. Galambos showed some optimum cavity beta calculations. For the nominal 
cavity peak field of 27.5 MV/m and starting SCRF energy of 185 MeV, the 
optimum betas are about 0.61 and 0.79. If the peak field is increased to 
34 MV/m, the optimum betas are ~ 0.63, 0.81, but the magnitude of the low 
beta value is less important. Similar optimum beta values result for the 
case of a ingle SCRF cavity family, and an extended CCL. In this latter case, 
the final CCL energy is important; at least 315 MeV should be provided.

J. G. Wang discussed Target Interface activities, which include:
1) radiation damage to the HARPS. This is unknown now but being investigated. 
2) dipole steering to correct for differential ground settlement. J.G. will 
check with the conventional facilities people to get values for the 
settlement. 
3) The reliability of the beam profile measurement on target from the harp 
is likley to be uncertain. It was suggested to ensure that other more direct 
measurements at the target are available (thermocouples, BLMs, etc.).
4) The requirement of the beam footprint on target is difficult to achieve 
due to scattering in the window. The target group will try to provide 
desirable beam distributions at the target. 
5)JG is doing Transport simulations for the spreader optimization, 
participating in Target group activities, updating them with the latest 
accelerator information.

Slava Danilov reported that the impedance of the kickers extraction appears 
to be too large (from measurements) - at levels that would cause 
instabilities. He is working on a theoretical explanation of the measured 
values. He suggests that the reason may be the high ferrite permiability. 
Lowering the mu value would reduce the impedance to accaeptable values, at 
the expense of poorer field quality (likely not an issue) and larger power 
supply requirements. 

Marc Doleans is considering thesis work in the superconducting area.