[Halld-pid] Start Counter Meeting Minutes, February 5, 2015

[Mark Ito]

Folks,

Please find the minutes below and at

https://halldweb1.jlab.org/wiki/index.php/GlueX_Start_Counter_Meeting,_February_5,_2015#Minutes 
.

   -- Mark
_________________________________________________________

GlueX Start Counter Meeting, February 5, 2015
Minutes

  * *FIU*: Werner Boeglin, Mahmoud Kamel
  * *JLab*: Mark Ito (chair), Eric Pooser, Simon Taylor, Beni Zihlmann


Start Counter Re-Installation

  * Next week we will get a new flange for the target cart to solve
    interference reported at the last meeting. Re-assembly can start then.
  * There is a plan to attache a 1.5 mm plastic target to the nose of
    the start counter. It will be attached to the light-tighting tape in
    some manner or another.
  * Tim Whitlatch's plan is to evaluate any tilt once the start counter
    is mounted on the target cart and then evaluate if any further
    adjustment is necessary.


Matching with Charged Tracks, Etc.

Simon led us through his recent log book entry 
<https://logbooks.jlab.org/entry/3318890>.

  * There appears to be some sort of cabling or translation
    transposition in two places in the start counter. The azimuthal
    difference between the center of a counter and the intersection
    point of a charged track shows anomalies for counters 1 and 2 and
    for counters 21 and 22.
  * He has rotated the start counter in the geometry. This turns out to
    be a somewhat tedious exercise; it is not simply a rotation of a
    single solid body. The tilt is visible in the r-z distribution of
    intersection points that he showed.
  * The "fuzziness" noted last time in the nose region was due to an
    overly wide azimuthal matching cut. Improvement is marked. The more
    reasonable value has been checked into the commissioning branch.


Basic Signal Assessment

We had some discussion on understanding and controlling our thresholds, 
both for the FADCs and TDCs.

Retrieved from 
"https://halldweb1.jlab.org/wiki/index.php/GlueX_Start_Counter_Meeting,_February_5,_2015"

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