Summary of the MuCool Meeting on march, friday 26th 1999

Simulation Studies (Paul Lebrun)

Paul Lebrun summarized the effort of using COSY as a beam optics code to design
beam lines with solenoids,cavities and cooling stages. The has been a main
issue for a number of weeks and in the optics meeting taking place regularly on
mondays. Preliminary calculations showed that the emittance is dependant on the 
order of the taylor expansion. This can be problem of the code or a problem of 
the beam transport and has not been determined yet. The question is, with 
what order of the expansion we have to run cosy with in order to get good 
results.  Another check of cosy can be done by using the dpgeant and track the
same channel to see what the emittance growth is in this case. The first attempt
failed because in the cosy simulation the canonical angular momentum was not
taken into account. In addition, Paul will try to implement a new method of
calculating the phase space and compare this to the standard method used so far,
which is summing the squares of the particle offsets to get the 
standard deviation.  With the method proposed by Dave Carey, the phase space is
divided in bins and bins which are populated by one particle are contributing
only the bin size and not the full deviation from the center. 
(Emittance= Nr. of nonempty cells x volume of the cells)

Paul also presented emittance calculation with and without including tails to
see the contribution. In the example he used, the non gaussian part was
counted as losses. In addition to that the question was asked whether the 
aperture of the cavity could be decreased without significant increase in
loss which would help the shunt impedance in the cavity a lot. So for
aperture cuts were made in the low Beta region and from the simulation is
seems that reducing the aperture is not possible. More detailed investigations
will be done as soon as possible with aperture cuts in the cavity. A little
confusion came up when the actual numbers where compared. Paul will do the
simulation again. 

The next agenda point was an update on the cavity R&D in LBNL. Derun
summarized the work going on. Poeple are preparing the cold test of the
Beryllium window cavity. Also the tuning and measurement goes on. While the
cell frequency of the cavity is too low by a few MHz the coupling cell shows
a more significant deviation which can only be corrected by shimming. This
will be done soon. Main reason is the use of round center conductors instead
of square ones. The Q of the clamped cavity is only 6000 which seems very
low. The natural Q should be around 20.000. For the Beryllium cavity design
Neill Hartmann and Eric Wu started with the simulation of the window in the
iris. Also the single cell (pill box) cavity design has been started already.
Vincent Wu from Fermi will go to Berkeley for 4 weeks and work on couplers
for the 3 cell test cavities. 

Next agenda item: Wedges and Rick Fernow
rick uses the beam coming out of the simulation of a 15 Tesla solenoid
channel (baseline design for mucool). The 6D emittance after the wedge is
still growing by approximately 50 to 60 %. Following the advise to increase
the field from 3.5 to 5 Tesla and the dipole field from 1.5 to 2 Tesla
shortens the Lamor wavelength and increases the number of Lamor wavelength
in  the channel. The optimum angle is between 53 and 135 deg. Still the is
an emittance growth of 40 %. The check suggested to see how much aberration
is produced by the bent solenoid (check by sending it through another bent
solenoid to cancel the effect) does not work. It seems like the emittance
filaments much faster. 

Next agenda item: Alan Bross:  TPC report
most of the components are on order. Lab 6 will be used for the test setup.  
For the design the electric field contour will have to be optimized to reach
the goal of having the super high timing precision. The field integral on all
path should be constant in the TPC. For test a 7 to 60 GHz bandwidth is
required. The laser, used in A0 to drive the Electron rf gun could be used
for that. 

next agenda item: Steve Kahn:
Investigation of the momentum resolution in the cooling experiment. The fit
for the resolution so far delivers a value of 3 MeV. for the sigma while
originally .15 was required. Steve will go on with the simulations.