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September 29, 2011 FDC meeting


  1. Production Construction Tracking (Dave)
    • Status
    • First package tests (Lubomir)
  2. Engineering update (Bill)
  3. Electronics update (Chris)
  4. Chamber testing at EEL126
    • Status (Beni)
    • Cathode resolution of the second cell (Lubomir) [1]
  5. Other


Participants: Bill, Dave, Chris, Simon, Beni, Vladimir, and Lubomir.


- Dave: Working on the sixth (last) wire frame for the first package; all wires soldered and today will do tension measurements. The fifth wire frame will be populated tomorrow by Chris. On Monday we will do the wire deadening on that frame and then it will be ready for stacking. Started working on the end windows and first cathode for the package #2.

- We have four cells in the first package as of Tuesday evening. Finally we fixed the gas leak in the second cell (at the third attempt): a bubble in the epoxy inside the chamber (that seals the gap between the solid part of the g10 and the PCBs) made a path for the gas to leak. A missing part of the trace on a signal wire in the third cell was fixed by Dave. All the channels of all the wire planes and cathodes were checked with a generator prior the installation. We had to replace the top spacer ring because it turned out after the first installation that the gas openings were not drilled there. Bill proposed to check the flow trough the gas openings relatively, using a rotarmeter with a fixed impedance.

- Lubomir: we could not have the stack with the four cells bubbling when using a many-fold at the output. That's why we separated the outputs and put additional impedance at the output tubings: 2m long thin tubes. That resulted in almost equal pressure in all the chambers of ~30Pa at 40 ccpm total gas flow. The pressure inside the chamber was different by up to 10Pa when using the many-fold. No explanation of this effect, but just adding thin tubes at the output is a simple solution; at the same time it will prevent over-pressure.

- Vladimir started already testing the package: yesterday he checked the third cell, today he was working on the second cell. The new fourth cells is not conditioned yet: we are at +1500/-500V now. Finally we have the 55Fe source (from RadCon) at Blue Crab and not only the testing is much faster but one can compare the amplitudes at the different channels.


- Bill: has drawings of many parts and tools ready, but waiting for the new fiscal year: new hubs and fixture, cathode pusher, endoscope holder.

- Bill will design protective covers (out of some plastic). They will stay on the package during transportation and most of the tests can be done also with them. Bill also explained his ideas about the connections between the packages, the order of installation and the cabling. Since there will solid g10 cylinders between the packages we can remove the protective covers inside but will keep the two outer covers till the final installation.


- Chris working on the extension board to look directly at the signals from daughter cards; had questions about the pin configuration that we need.

- For the first package tests we need the pre-amp card to hold the cooling tubes that we will use also as a ground. These could be also dummy cards and we discussed what is the best approach. Without information from Fernando when we will have we the pre-amps ready we could not decide. So far we have 10 first article cards.

Chamber testing at 126

- Beni and techs made a lot of progress in 126: new cable frame is installed, now working on the cables and the new crate, need more F1TDC.

- Lubomir showed results about the resolution of the second cell (page 578 FDC electronic logbook). Eugene needed such plots for the Lehman review. Beni will modify also some of his results at pages 572-573, about the chamber efficiency and drift time spectra.


No meeting next week due to the collaboration meeting at the same time.