August 15, 2012 traccking CDC/FDC
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Meeting Time and Place
Wednesday August 15, 2012 at 11:00am At Jefferson Lab, the meeting will be held in F326
Connections
To connect from the outside, please use ESNET
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Hardware Agenda
- Announcements
- CDC Update
- TDR Update
- Calibrations
- CDC Garfield simulations
Minutes
- FDC Update
- Copper corrosion: with several tests we were able to reproduce the corrosion we had on the first and second packages. It's a combination of sulfur most likely coming from the EPDM, water due to humidity and absorption in the EPDM, and carbon as a catalyst also from the EPDM. Using Viton also may result in some corrosion, but we have never seen corrosion when adding vacuum grease. Two solutions of the problem discussed: just using Viton+grease as in the last two packages, or in addition covering the cathode at the O-ring position with Kapton foil using epoxy.
- Conductive tape technology: another important decision we have to make soon is whether to continue with the z-axis conductive tape to connect the daughter cards to the cathodes, or use conventional soldering on 2micron copper traces. Latests test show the problems we found on some channels (few percent) are due to mechanical deformation of the cathodes, not aging of the conductive tape. Therefore the solution would be to make sure the cathodes stay flat during the whole production, installation and operation of the chambers.
- CDC Update
- TDR Update
- Calibrations
- CDC Garfield simulations
- FDC Garfield model was modified to be used for the CDC. Some plots linked above demonstrate the cluster production along the track, row signal on the wires and also folded with the electronics response. All the examples are for 1GeV proton tracks perpendicular to the wire at different distances with no magnetic field. The last two plots show the average total charge and maximum amplitude as a function of the track length within the cell. In case of the charge there's proportionality, except for small distances to the wire; this is not the case for the max amplitude.
