February 29, 2012 Tracking CDC/FDC

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Meeting Time and Place

Wednesday February 29, 2012 at 11:00am At Jefferson Lab, the meeting will be held in F326


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Hardware Agenda

  1. Announcements
  2. FDC Update logbook
  3. CDC Update
    1. Construction Update
    2. Cosmic Calibration of the Chamber
  4. TDR Update

Tracking Software Agenda

  1. Announcements.
  2. Summary of current work on tracking.
    1. Automated single track reconstruction now working...
      1. Note: hit pruning is on by default, but track recovery (for tracks with kinks or too few hits surviving pruning) is currently (2/29/12) not on by default.
    2. Problems with track finding in CDC

Hardware Minutes

Participants: Curtis, Naomi, Beni, Simon, Lubomir, Elton, Dave

  1. FDC Update
    1. Production: two cells of the third package installed and tested. New electroplating procedure seams to be working fine: the two cells held HV for several days. Today the third cell will be installed and tested by Friday.
    2. First package tests: long discussions and exchange of ideas about the problem that we found about 1% oxygen in the exhaust gas (which is the reason for the lower efficiencies). The main suspect for the oxygen origin are two air pockets on each cell between the cathode and ground plain connected to the main gas volume only through 18 small (~2mm diameter) holes around the periphery. Beni: we moved the package in vertical position (oxygen is lighter) and today connected a pump at the exhaust at the top to reduce the oxygen contamination. Will monitor the oxygen percentage and depending on its change will make further decisions. Most of the proposals to fix the problem require opening of the package that at the moment we want to avoid.
  2. CDC Update
    1. Wire stringing has been completed and the chamber lowered to horizontal.
    2. We are expecting the survey team from JLab next week, the plan is to survey the 200 holes which were surveyed previously with a Faro arm.
    3. The resistance of the wires will be measured after the surveying.
    4. We are planning to use Al standoffs in place of the brass ones because their resistance is similar and Al is so much lighter.
    5. Calibration with cosmics is undergoing discussion. We have been thinking about possibilities for calibration with scintillator paddles above and below the magnet.
    6. We are starting to work on the TDR.
  3. Surveys
    1. A discussion on what could be surveyed for both the CDC and the FDC were started. It was noted that a JLab survey team would come to CMU next week to survey the pin holders on holes that were measured on the end plates when they arrived. This information will give us an idea of the run out that should be expected from the feedthrough to pinholder connection.
    2. For the CDC, there are monuments on both the upstream and downstream end plates that will be visible once the chamber is installed in the magnet. The length (z-coordinate) can be measured before the chamber is installed and then a survey of the end plates will give us a reasonable set of starting locations for the wires.
    3. For the FDC, the most upstream and most down stream chambers will be able to be surveyed in place. It was also noted that the packages will be connected to together before installation providing an opportunity to measure the relative orientation of the four packages with respect to each other.