From norem@hep.anl.gov Wed Dec 23 16:04:20 1998
Date: Mon, 21 Dec 1998 10:21:37 -0500
From: Jim Norem <norem@hep.anl.gov>
To: Ray Stefanski <stefanski@fnal.gov>
Subject: Muon Cooling Experiment Meeting notes from Dec 18

Notes of Muon Cooling Experiment Meeting

Present:  R Stefanski, E Black, D. Kaplan, P. Spentzouris, A Moretti, J.
Norem, N. Holtkamp, Z Qian, P. Lebrun, D. Carey, D Neuffer.  
J. Corlett (LBL phonelink)

There was a very quick summary of the meeting of the Cooling, target and 
Technical committee meetings the previous week.

There was felt to be a general need for a standard list of cooling parameters
for the transverse cooling section: coil positions etc for monte carlo work.
The parameters are changing and it is difficult for those doing the 
calculations to compare results for similar but not identical configurations. 

Norbert presented a detailed outline of the proposed lab G tests which will
take place over the next year.  The work included designing a standing wave
cavity and building an Al model.  He proposed building two high power cavities
with two cells each to look at both windowless and Be ^Cwindow cavities.   The
aim would be to generate gradients of 35 MV/m at 805 MHz.  This would involve
looking into 60 - 100 MW klystron development. There was discussion of 
who would be involved with this work.  Limited funds make it somewhat more 
difficult to follow two options.  There will be decisions made on what the 
detailed experimental priorities will be at the next cooling theory and 
experiment meeting to be held in LBL on April 12-14.  In the meantime the 
design of open cavities has a high priority.

J. N. proposed making the cavities more tolerant of window deflections by
insuring that all deflections were in the same direction, with the end cavity 
half as thin, so its deflection would be equal to the others.    If this was 
done, the capacitance could be more insensitive to deflections because the 
cavity length would be unchanged, since the convex and concave deflections 
would tend to cancel.  Al Moretti pointed out that this option was 
already under study.

Dan Kaplan presented data showing the results of DPGEANT runs with variable
magnetic fields down the length of the LH2 target.  When the magnetic field 
was increased from 15 T to 16.9 T the there was a 10% decrease in the output 
emittance of the beam.  This was evidently a result of decreasing the 
equilibrium emittance to somewhat follow the decrease in the
beam emittance.  If the downstream field was increased from 13.1 T to 15 T
there was no decrease in the beam emittance.  These results seem to indicate 
that more efficient cooling is possible, and also that more variables are 
required in our experimental setup.  It seems as though we should want control
of the field profiles in the degrader region, which does
not seem to have been in the design so far.  Cooling seems to be a sensitive
function of  many parameters and a more complete calculation of this effect, 
including variable fields in the linac region (where the field increases with 
momentum) seems necessary . 

G. Silvestrov is expected towards the end of January.  There is a plan for the
Argonne group to have some calculations with liquid lithium done by that time 
to begin to evaluate the limiting behavior of the lens at high fields and high 
powers.