Replacing a Wedge on a Disk

Locate the special tools and components that you may need: http://www.phenix.bnl.gov/WWW/fvtx/BNLAssembly/tools/tools.html
To remove the wedge: Hook up the ROC and run a calibration to see the bad wedge Disconnect the extension cable from the ROC, using the pair of levers (picture 2 on the tools page) Run the calibration again, to verify you got the bad wedge. Disconnect the bias cable from the ROC board, and cut the cable tie that bundles 8 bias cables together. Remove 2 screws that hold the wedge, using the torque-limited screwdriver with the blue shrink tubing on the tip. The tubing prevents the screw from falling. The thermal grease will not hold the wedge. Lift off the wedge. On the bench, disconnect the extension cable from the wedge, using the special tool (picture 3,4). Note there are different versions of this tool. Disconnect the bias cable from the wedge, using tool from picture 7. Clean the thermal grease from the disk with a q-tip (dry), if there is any.
Prepare a new wedge: Select a new wedge. Look here and look for 'unussigned wedges'. Bend the HDI. Bending (1) (2) (3) (4) (5) (6) has to be done before attaching the pedestals Attach graphite pedestals: Here are the jigs and instructions for attaching the pedestals Attach a grounding wire
(3) Grounding wire: see http://www.phenix.bnl.gov/WWW/fvtx/BNLAssembly/wedge_grounding.html http://www.phenix.bnl.gov/WWW/fvtx/pictures/bnl_pic_Nov2010/injectwire/index.html and pictures 83-86 on this page: http://www.phenix.bnl.gov/WWW/fvtx/DetectorHardware/Assembly/pictures/RAW_BNL/index.html. When I made these, I pre-bent the wires to follow the edge of the HDI, so they don't get snagged later. make sure you have the right solder, and use very little of it. Silver epoxy the other end of the ground wire into the hole fix the wire in a few places with a few drops of hot glue.
Mounting the new wedge: Test the new wedge Connect the extension cable to the wedge Connect the bias cable (tool 5 or 6) Apply a SMALL amount of grease to the feet. This stuff does not squeeze out like glue. Apply a small amount of grease to the disk. Note in the photo, there is almost no trace of the white thermal grease on the disk. So I rubbed some on the disk. You can only do this on the big end. Screw down the wedge, using the torque-limited screwdriver Connect the extension cable to the ROC Connect the bias cable to the ROC, and re-tie the bundle Do a calibration to see that the new wedge is there.