MUCOOL meeting 9/24/99 notes

Tollestrup, Moretti, Kaplan, Norem, Black, Geer, Yu, Neuffer, Carey, 
Buckley-Geer, Qian, Monree, Jergan, (+ Corlett . . .)  ((+LeBrun))

Scribe:  Jim Norem

News:
    Al Moretti mentioned that Brush Wellman had costed the Be tubes
    for one of his cavity options at 49 k$ for 50 cm of 4 cm tube.  
    (100K$/m ! ! )  Do they have the real requirements?  The albemet
    alloy should also be considered.

   Jim Norem reported that the x-ray measurement had been ready for beam
   for a while, but was experiencing scheduling delays.

John Corlett presented the numbers on a 200 MHZ cavity to be used 
with the low frequency cooling experiment.  A first iteration has been presented
in MUCOOL note #50, but some rf parameters in this note were not realistic.
A new analysis is being performed, with pillbox cavities are 37 cm long, 
with the radius of 66 cm.  They will run a a peak E of 14 MV/m which is
roughly 
the Kilpatric limit.  The shunt impedance will be approximately 80 MV/m, and 
the Q = 45,000.  It is assumed that they will be powered by 1 MW tetrodes
each and paired so there will be 2 in a cell.  The duty cycle will be about 
0.002 to each cell will get 2 kW.  It is assumed that the problems will
be breakdown and effects associated with the cavity ends.  The cavity aperture
(Be windows actually) will have a radius of 30 cm.  The suggestion was made
that this setup have the same aperture as Al's (32 cm) to make comparisons
easier.

Al Moretti mentioned a cavity design with a Tesla like geometry with a R=59cm
and L=60 cm with a aperture radius of 32 cm.  The radius of the annulus would 
be 8 cm.  He got a Z = 45 MOhms/m and a Q or 70,000 with a E(peak)/E(acc) = 
1.75.  Corlett suggested two cavities would accelerate more efficiently.

Al's cavity design will reside for a while at 

   http://mac15.hep.anl.gov  

The discussion of the 175 MHZ R&D was severely attenuated by the absence of 
Norbert, but the feeling was that this test should take place at Fermilab.
Evidently there is little difference between f=175 and 200 MHz technology,
with the former suggested by CERN LEP cavities at 352.2 MHz (352.2/2=175?).

Jocelyn Monroe presented a calculation of multiple scattering effects done 
along the lines suggested by Alvin.  She showed how Rutherford scattering
theory was extended to muons and how scattering effects due to electrons
should be treated correctly.  Moliere started with a transport equation and 
then parameterized things according the the number of scatters (which is 
related to the path length and material), and a constant which characterizes 
scattering.  The Thomas-Fermi model is good for almost everything, but 
perhaps less good Hydrogen.  Scattering off protons and electrons contribute
equally up to a kinematic cutoff.  Form factors for total and elastic 
scattering were presented.  The net result seems to be that multiple
scattering distributions for hydrogen  should be 7% narrower than is assumed
by DPGEANT.
This calculation is being extended to molecular H2 and a comparison will be 
made to single scattering.  Magnetic field effects may be quite significant 
and Paul LeBrun is predicting a large effect.  This may contribute to the
difference between SuperFOFO and Alt Sol geometries.

Panofsky and Bernstein evidently did this calculation right some time ago and 
discovered that the molecular effects are on the order of 3%.

There has been some talk of an experiment at ISIS, but the experiment has not
yet been designed.