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| − | Participants: Eugene, Dave, Chris, Simon, Beni, Glenn, and Lubomir. Relatively short meeting. | + | Participants: Eugene, Bill, Glenn, Chris, Roger, Simon, Beni, and Lubomir. |
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| | == Production == | | == Production == |
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| − | - We found discoloration spots on the first cathodes that were produced at Blue Crab. The spots are brown but have blue color at the periphery. There's one spot covering several thin traces close to a connector. Eugene explained the finding done with electron microscope by Olga: chlorine was found, so most likely this is copper chloride (brown) and copper chloride dihydrate (blue). We suspect chlorine is left from the etching procedure (have to verify that Allflex uses ferric chloride for etching). Then the effects we see is due to the wetting of the foils, this is needed for the alignment and gluing the panels together. So far we exclude the possibility that the copper reacts with the new packing paper. This is due to the fact that we see more spots on the first article foils than on the production foils. Still, we are waiting to hear from Andy Wu who will do independent analyses. Eugene, Lubomir and others agreed that Allflex should continue with the foil production. | + | - Problem again on Monday with the HVAC at Blue Crab: same transformer failed. It will be replaced with one with higher power, but the origin of the problem is not clear. |
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| − | - Dave: many problems this week. Still waiting for some signatures on some of the procedures. Yesterday there was a problem with the AC (due to transformer problem, second of this type) in the clean room; the humidity went up to 70%. It was fixed but Ron Bartek suspects a problem in the design. The power went out this morning, maybe related to Surry power plant shut down. It turned out according to Rusty Sprouse, we can't use the temporary light that we have outside of the clean room. The heater in the ultrasonic cleaner doesn't turn off; the ultrasonic cleaner was shipped back to the manufacturer for repair. | + | - Two cathodes are glued to the frames, including the flaps. Next steps: tensioning/gluing the mylar and gluing the mylar flaps on top of the copper flaps. We have to decide what should be the tension on the mylar: it's not as critical as for the kapton foil. For gluing the mylar flaps Bill suggested using conductive epoxy only in the area overlapping with the copper flaps, and regular epoxy over the g10 frame. Mark made the template needed to make holes on the mylar. |
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| − | - The granite plate used for cathode flatness measurements was successfully moved to Blue Crab. Eugene suggested to check the flatness of at least one cathode, but it doesn't have to be the first one. We will do it later; don't want to spread our efforts to many projects when we are late with the first production chamber. | + | - |
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| − | - After several improvements in the cutter (stronger blade, modifications in the blade holder, and very importantly cutting on wet plastic tape as proposed by Anatoly) it's not wobbling now. Second cathode foil was glued. Second PCB ring was glued. As of now, the highest priority is the wire frame lamination, so that we can continue with the stringing. Then, in parallel we will work also on the cathodes.
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| | == Electronics == | | == Electronics == |
