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| | = Minutes = | | = Minutes = |
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| − | Participants: Eugene, Bill, Dave, Chris, Nick, Vlad, Simon, Beni, and Lubomir. | + | Participants: Fernando, Eugene, Bill, Dave, Nick, Vlad, Simon, Beni, and Lubomir. |
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| | == Production == | | == Production == |
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| − | - Dave: Tina is soldering wire frame #29. Mike is working on the PCB ring for #30. Five new g10 wire frames (we asked for four) were made by Vision machine, then we laminated the Rohacel rings and sent them back to Vision for the fly cut. | + | - Dave: Forth cell of the first package was installed yesterday, today we put a cathode from the fifth cell, tomorrow we plan to finish also the last cell. |
| − | | + | We are using the six spare cathodes made at the end of the production. |
| − | - Vlad: testing the first three cells of package #1. The oxygen went down to 170ppm, we started flushing on Sunday. All the channels of the three cells were tested with a source and scope and are working fine. One pre-amp card was noisy, has to be replaced. Currents of the positive HV are higher in all the cells: 940nA, 82nA, and 350nA for cells 6,5, and 4 resp. This is to be compared to 149nA, 13nA, and 62nA we had in October 2011 when the same wire frames were in the second package: about a factor of 6! We will check the HV supply.
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| − | - Lubomir: on Sunday Vlad found the gas bottle at Blue Crab (supplying gas to the first package and the testing vacuum chamber) empty due to high consumption of the testing chamber. The vacuum pump connected to the oxygen sensor through rotameter (~200ccpm) started sucking the gas from the chamber.
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| − | The mineral oil in the bubbler filled completely the thin vertical tube (55mm corresponding to ~500Pa) but didn't go up in the spherical section of the bubbler. The top end window (2mil Mylar) had spherical shape meaning it was not touching the ground below it. After replacing the bottle on the same day, everything recovered. Vlad tested for leakage <5*10^-5 ml/sec about what was before. Beni is afraid that bending inward may cut the window if you have some epoxy sticking out of the frame. Bill: we need to find a way to turn off the pump when the pressure in the chamber drops. Lubomir: for now we can turn off the pump manually every evening, but at the same time have to reduce the flow in the chamber so that the pressure doesn't increase, which will result in inaccurate O2 measurements.
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| | == Cathode corrosion == | | == Cathode corrosion == |
