May 12, 2011 FDC meeting
- Status and plans (Dave)
- Wire tension scan logbook page 565 (Lubomir)
- Engineering (Bill)
- Package assembly design
- Electronics (Fernando, Chris)
- Rigid-flex stuffing
- Chamber testing (Beni, Lubomir)
- Gas system at Blue Crab
- Equipment for Blue Crab
Participants: Eugene, Bill, Dave, Chris, Simon, Beni, and Lubomir.
- Dave: The first two cathodes are assembled waiting for the rigid flexes. Anatoly is cuting the wires on the first wire plane right now. The third cathode is tensioned and the frame glued; next is to tension and glue the ground plane. Fourth cathode is ready to be tensioned. The ultrasonic cleaner is back and Al is installing it now. We will fill it with distilled water. The frame will be cleaned first with Vigon and then put in the ultrasonic cleaner. We are waiting for the tool ring needed to tension the end windows.
- Final results from the position and tension measurements of the first production chamber are shown at page 565 of the FDC logbook. We decided that we have to fix the offset in the pin position of the jig rail. From the position measurements (as explained at page 565) the pitch is short by ~130 microns. Dave measured it directly with a caliper and found ~100microns which is consistent, given the precision of the caliper and the fact that 130microns is the gap averaged over all the wires on both sides. Bill will bring the pin rail to the machine shop for fixing it and will try to expedite this since it stops the wire plane production. His idea is to increase the hole sizes so that one can vary the gap, to map the positions of all the pins and thus to adjust the gap, after that to put pins to fix the position. Tension measurements were done in a half a day, the voltage on the generator was kept 1V for both field and sense wires (before we used 3V for the sense wires). We found one sense wire broken between the solder pad and the glue; it was replaced by Casey. One of the filed wires had lower tension because of its weight touching the lower plate of the weight shielding. This most likely happened because the screw used to attach to the wire was not so tight and the weight slipped. Adding to the procedures: before gluing the wires one should open the shielding and check that all the weights are hanging.
- Bill: problem with one machine at "Vision Machine" and that's why we are still waiting for the ring needed to tension the end windows and for the jig plate needed for the chamber assembly. Hopefully we will have these at the beginning of next week. The parts for the ultrasonic cleaner and the tool to tape the wires (with Kapton dots) are in the machine shop. Finally we have the four penetrations in the clean room done. We don't have to vent the gas out of the clean room, so the bubbler for the tests will be inside.
- Tools and parts needed for the package assembly (and also for the first chamber testing): Bill prefers to have one gusset for one side of the package instead of many sectors, though it will be more expensive. The tooling will be similar to the one we used for the full-scale prototype, some parts (like the hubs) are now on the prototype, but Bill will make a second set so that one can be used for testing and the other for assembly. For the first chamber tests we will take the parts from the full-scale prototype. Eugene suggested not to disassemble the prototype so that we can do comparative tests if we have to. Therefore we will take only the hubs and replace the gussets with plastic ones.
- After the meeting Bill, Dave and Lubomir went to 126 to discuss the procedure for the partial disassembling of the prototype. We decided that the best is to transport the prototype to Blue Crab and replace some of the parts needed for the first chamber assembly and testing. Such replacement will be done sector by sector so the prototype will be affected minimally. We need to take the hubs and some of the rods. This will happen beginning of the next week and we better use a van in which we put the chamber horizontally on a flat Lexan plate.
- Chris: hopefully we will have the first 100 rigid-flexes populated at the end of the next week. Then we need another week for gluing them and then one more week for assembling the chamber and setting up the tests. We decided we couldn't delay the tests that much and we need to populate 18 rigid-flexes manually. Lubomir already discussed with Fernando a week ago if Chris can do this for us.
- Chris: the last 16 (of the first 50) signal cables have arrived and tested, they are OK.
- For the gas system Beni wanted to have the right connectors instead of using putty at several places. Bill will order these (not from Lowes).
- Lubomir: the first chamber (as well as the packages later) will be tested in 126 in two positions: vertical, for gas leakage and with a source, and horizontal, with cosmics. For the horizontal position we will use additional plates/frames as with the full-scale prototype to make the construction stiffer. For the first chamber we will take these parts from the full scale prototype.