Minutes from target meeting held February 25 2010 in 892-2-009

These minutes are available also from:

http://wwwcompass.cern.ch/compass/detector/target/Minutes/2010/

a) Jaakko: fill mixing chamber volume with helium-4. Start circulating gas in 
helium-3 circuit through the LN2 trap. Install LHe transfer line for the 
dilution cryostat. Pump transfer line isolation vacuum. Start small transfer 
of LHe for precooling and purging. Check thermometers and NMR coils on the 
target cells. Reinstall helium-3 filling tube with new heater to the bottom 
part of the target cells. Leak test target holder isolation vacuum. Small 
diffusive leak close to SMA connector #7 found on the mixing chamber side. 
Needs to be repaired.

b) Fabrice: magnet safety system tested with simulated quenches. Full field 
rotation, field rotation at 1 T and slow discharge tested with short circuit
on the power supply cables. Magnet precooling with LN2 started on Monday.
On Thursday average temperature of 170 K reached.

c) Kaori: new PXI crate position to be moved close to the Saleve side concrete
wall on the same level as the magnet axis to minimize the stray field. Measure
Q-curves with the PXI. Connection between the NMR and magnet PC working.

d) Norihiro: dilution cryostat PLC stopped once. Magnet failure signals and
cryogenic signals for LHe and LN2 to be connected. Pump cooling water pressure
display was discussed.

e) Yuri: install new microwave PSU in the rack next to the microwave table.
Make mechanical connections to the EIO tube. Test cooling water flow.

f) Gerhard: remaining NH3 material from Bochum now stored at CERN. The dewar
has fast boil off and needs to be filled every 7 days. For the prototype target
holder two different teflon meshes were tested. The Japanese mesh had a high 
proton content while the Swiss mesh gave no proton signal. There will still 
be a residual proton background due to the surrounding Kevlar-tube, glue and 
teflon inside the NMR coaxial cables.