Minutes from target meeting held April 6 2006 in 892-1-B09 These minutes are available also from: http://wwwcompass.cern.ch/compass/detector/target/Minutes/2006/ a) Three target cells are ready. NMR coils need to be connected to the SMA connectors. A small coil for 1 T deuteron or proton transverse measurement will be added. b) Norihiro prepared field sweeping state diagrams for the magnet slow control. c) Installation of the three target cell cavity was started. Tight fitting between the upstream conical steel part and copper cylinder flange. The three waveguides were soldered on the cavity. d) Andrea Raccanelli from Bonn University gave a talk on the Finite Element Model for the Thermal Transport in Target Materials on Monday April 3. Polarization relaxation in lithium target in muon beam and possible plans to use the polarized target in hadron beam were discussed. e) Jaakko estimated the heat flux from the reentrant vacuum window to be 5 - 44 W depending on the emissivity of the surfaces. This corresponds to additional boil off 0.1 - 0.8 l/h. With 5, 10 or 30 layers of superinsulation the heat load can be reduced to 0.7, 0.37 or 0.13 W. A plastic 9 mm long 4 mm diameter spacer/stopper would contribute 0.25 W in the worst case. Tapio: heat flux to the cavity needs to be minimized using superinsulation layers. Cryolab will help in installation of the superinsulation layers. f) Jaakko: using the measured dimensions from the vacuum window and the conical thermal screen I produced a drawing: http://wwwcompass.cern.ch/compass/detector/target/magnetwindow/im1.png If the screen is centered to the vacuum window minimum clearance on the conical part seems to be 9 mm. The clearance is 14 mm between the aluminum foil and vacuum window. Similar check was done for the upstream screens: http://wwwcompass.cern.ch/compass/detector/target/magnetwindow/im2.png The minimum clearance seems to be 8 mm. The upstream screens will be cut to two halves to make installation easier. g) Filling of the target shifts for 2006 has started. See http://compass-target.web.cern.ch/compass-target/shiftlist2006.htm