Minutes from target meeting held May 20 2011 in 892-1-B09

These minutes are available also from:

http://wwwcompass.cern.ch/compass/detector/target/Minutes/2011/

a) Start helium-3 roots on Monday morning. Small water leaks from the large
and medium size heat exchangers. Stop the pumps and disconnect the water 
connections for drying the heat exchanger tubes with air flow. Cover the 
leaking tubes with Eccobond 286. Let the epoxy dry until Tuesday morning 
at about +24 C. Reconnect the water pipes and start the water flow. Start 
the roots and pump dry nitrogen from 14:00 until Wednesday 11:00.

b) Pump vacuum to the helium-3 roots and open the gate valve bypass VH2.
Start to circulate helium-4 through the LN2 trap. Start to put LHe slowly
to the dilution cryostat separator to cool down the thermal screens and
the microwave cavity. Small flow of helium also through the evaporator to the
helium return line. Helium-4 evaporator reached 7 K by Friday.

c) Magnet reached 95 K temperature by Wednesday morning. Disconnect the pipes
for LN2 precooling. Insert the LHe transfer line into the magnet helium
vessel. Start cooling down the magnet with liquid helium. On Friday morning
20 K temperature reached.

d) Problem in the electricity distribution of the control room prevented 
the computers to operate normally. After using different power sockets
the normal operation could be recovered.

e) Norihiro: new PLC modules for the pt100 resistors need a new version of
the Step 7 program. One current input module is going to be used in
the pump room to measure weight of the LN2 dewar. In addition a digital
input is needed in the control room to monitor that the largest roots
blower is running. DCS group plans to install ELMB to the pump room to
monitor the temperatures in the roots heat exchangers.

f) Fabrice: bug in the helium-4 pump PLC giving wrong signal for open water
valve. Using tap water for the cooling in the beginning. Before the rotary
pump is switched on it needs to be rotated first manually to get the oil
into different places. Replace the safety valve at the pump outlet with
a valve of larger diameter.

g) Add a new Pfeiffer full range vacuum gauge to monitor the isolation
vacuum. A free port at the upstream flange of the dilution cryostat was
used and the gauge was mounted on the cryostat top flange.