Meeting of January 8, 2001

Present: Ray Arnold, Peter Bosted, Don Crabb, Piotr Decowski, Steve Rock 

1) Peter did a little work on compatibility of experiments E160 and E161.
So far he finds that it is not easy to make the number of dipole
magnets the same: adding one to E161 reduces the hi pt acceptance too
much, while taking it away from E160 makes the J/psi mass resolution 
too poor (except at the lowest energy of 15 GeV).
   While it also seems hard to make the hodoscope planes the same
size for both experiment, Peter is working on an idea to transform 
one into the other simply by rotating the hodoscope fingers about
their long axis. The short side (about 1.5 cm wide) 
would face the target for E160,
which needs finer resolution, while the medium side (about 3 cm wide)
would face the target for E161, which needs bigger planes but not
as good a position resolution.  

2) Peter agreed to talk with Robert Avakian, which he did on Tuesday.
Robert said he has worked with the S. Africans before, and that they
produced synthetic diamonds which are nice, but maybe not as good as the
very good ones Robert got from the Russian military. The ones Robert
has are up to 1 by 1 cm with mosaic spread of less than 10 micro-rad
(this is incredibly good). A graduate student from Armenia, Arman Apian 
will be coming to SLAC in mid-January to work on calculations and start
looking at the goniometer. A priority for calculations is to check
the circular polarization of the coherent peaks (result elliptical?).
Another goal is to check Robert's idea that if we rotate the crystal
to the right angle, we can pick up *both* the (022) and (0-2-2) 
reciprocal lattice peaks, thus gaining a factor of two in coherent
photons for no increase in incoherent ones. If this works, it will
be a big improvement to all three experiments. Robert will also read
the Danish preprint on their diamond tests at CERN, and determine if
their finding are relevant for us. The worry is that with their 
orientations, there will be a huge number of low energy photons from
channeling, which would cause too much background for us. 

3) George Igo recently communicated that the UCLA group would like to
build a substantial portion of the scintillators. Here is this email:
Hello Peter:
     The project to build one or possibly more of the large scintillator planes would 
be a natural for UCLA. The team from UCLA would tentatively be Vahe, Steve, 
Chuck Whitten, myself and a grad student who would do a lot of the work on 
building the plane (planes). 
     You can inform the spokesmen for the experiments if you would. 
     We have to assume that the cost of phototubes, plastic scintillator  etc will be 
borne in some way by SLAC. As you know this did not work out last time and we 
managed to scrounge the good phototubes through our friend Don Miller. We don't 
see that as a possible option this time.
     We will be looking forward to setting up things more concretely at the 
collaboration meeting which I believe you are scheduling in February.
    Regards, George
 
4) Peter mentioned a discussion with Rory Miskimen at UMass. Rory is
obtaining 1000,  2 cm by 2 cm by ? cm lead-tungstate blocks to make
a high resolution photon detector for Primex in Hall B at Jlab, but
said only 500 of the blocks will be used there. If about 100 of these
blocks could be spared, they would be ideal for making a Compton
polarimeter that can be used to monitor the photon beam polarization.

5) Don Crabb reported that he has requested new price quotes for the
target magnet from Oxford including a dipole field, and a quote 
for new pumps. 

6) Don has also obtained four 4" by 4" by 4' very pure carbon pieces,
that we can use for our beam hardener.

7) We agreed to organize a collaboration meeting for Feb. 10. Peter
will start to organize this.