Minutes of feedthrough meeting of 8 January, 2001. ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Present: Pof, PB, GV, AD, TH, MLenc, ML *) Milestones - 62 Vacuum cables arrived on 20 December, and 72 Vacuum cables arrived on 21 December, and 119 Vacuum cables arrived on 2 January. The 20,21 December batches have been tested; three will be returned. Testing of the 2 January batch is underway. - The dye penetrant test was done on ft00, ft01, and ft02, and all passed. Written documentation for the tests is provided by SM. For future tests, the feedthroughs will be held vertically in the assembly jigs rather than horizontally on cradles. This will reduce the mess (and ease the cleanup) created by the dye penetrant material. *) The small format Tektronix digital scopes (TDS200 series) are limited to 100 MHz bandwidth, compared to 200 MHz for our present Tektroniz 2440 scope. Pof did some checks with the 2440 scope comparing cross talk measurments made with the full 200 MHz bandwidth with measurments made with the bandwidth limited to 100 MHz. No significant differences were observed. At the same time, the third set of scanner and fannout devices made by the UBC electronics shop was also checked out and found to be in fine working order. *) An add will be posted on Saturday 13 January for a new technician for the lab. *) Mark will produce some drawings this week to overlay the images of the cut-and-polished TIS weld sample in an attempt to clear up TIS's confusion over the most recent weld samples sent to them. TIS believes that there is a large cavity in the weld sample (or that the weld is not fully penetrating) when in fact the `cavity' they are observing is a mechanical feature well separated from the actual weld. *) Mark will attempt to work on the shipping crate design this week, after the drawings for TIS are completed. *) Bob Hackenburg of BNL notified pof of a new problem they have encountered with the FCI connectors: > Hi Paul, > > We recently discovered an embarrassing fact: The VacuumCable > connectors are not quite right. The problem is that they bottom out > inside the pinCarrier, instead of at the screw-points. This causes the > spring clips to bend up slightly (when the connector is fully screwed > in), which puts them too close to the pins, and prevents us from doing > (reliably) the 1000v hipot test which we also recently discovered that > we need. > > We have found an excellent solution, however. We now install nylon > washers under the screws, and this fixes everything (the connectors no > longer bottom out inside the pinCarriers). The PigTails do not have > this problem; they do not bottom out inside the pinCarrier. The > washers we use are perfect in many ways, including the fact that they > very nicely sit between the two rectangular protrusions at the bottom of > the connector, and stay there once put on (i.e., they don't fall out > when the connector is held upside down). The washers come from MSC > (http://www.mscind.com/), and here are the various numbers on the label > of the bags they come in: > > MSC part number: 67353169 > Other numbers: 16FW004062 > FW4-062 FLAT WASHER > > They come in bags of 100, and are something like $4.00 per bag. > > > I highly recommend this added step of installing these washers. I believe that the problem boils down to the improper placement of the ground shields, which has been causing a few other problems. Looking at the FCI cable drawings, the ground shields should not protude beyond the end of the plastic housing, when in fact they do on most cables. In principle, there should be 0.3 - .284 inches clearance between the bottom of the connector and the bottom of the slot. However with the ground shields protuding beyond where they should on many cables, they end up bottoming out. Washers have been ordred for our entire stock of vacuum cables. Agenda for next week: ^^^^^^^^^^^^^^^^^^^^^ - Milestones - plans for February LARG week - shipping crate progress??? - flange heater status??? - AOB