Minutes from target meeting held July 20 2012 in 892-1-D20

These minutes are available also from:

http://wwwcompass.cern.ch/compass/detector/target/Minutes/2012/

a) Make drawing of cylindrical symmetric materials on beam axis for the 
planned Drell-Yan target. Only the target cells and microwave stoppers are
different from the setup of run 2011 while the mixing chamber, vacuum windows
and radiation shields are assumed to be the same. The target is divided into 
simple geometries of different materials. See
http://wwwcompass.cern.ch/twiki/pub/Drell_Yan/DyPtDrawings/materialsDY.pdf
http://wwwcompass.cern.ch/twiki/pub/Drell_Yan/DyPtDrawings/materialsDY.txt
http://wwwcompass.cern.ch/twiki/pub/PolarizedTarget/DilutionCryostat/TargetHolderVacuum.jpg

b) Estimate target material in run 2011, see
http://wwwcompass.cern.ch/elog/target_polar/178

c) Yuri: paper on irradiated ammonia samples in preparation. The dynamic nuclear
polarization allows to see the nitrogen-14 in highly polarized proton sample
at low temperature below 1 K. 

d) Yuri: path for the waveguides needs to be defined for the Drell-Yan target.

e) Kaori: place the NMR rack to the control room for the Drell-Yan target.
The Q-meters would stay on the target platform, but they need to be tested 
first in similar radiation conditions that are expected next to the polarized
target. The NMR-cable length needs to be probably increased from 6 m to 10 m.

f) Yuri: the coax is part of the resonant circuit. Longer cable will result
in smaller Q-value. The cable can be sensitive to vibrations. 

g) Fabrice: magnet opened and removed from the LHe vessel. The protection
circuit is visible. Three resistors out of order and one melted. 

The screen temperature could be optimized by adding a helium cooled cold
head to the suspension cabling end now at root temperature.
 
h) Michael: Bachelor theses on "Low temperature proton polarized target for 
nucleon structure studies at COMPASS", Charles University in Prague (2012).
See
http://wwwcompass.cern.ch/compass/publications/theses/2012_bac_pesek.pdf