[Halld-pid] Time-of-Flight Meeting Minutes, April 11, 2018

[Mark Ito]

Folks,

Please find the minutes below and at

https://halldweb.jlab.org/wiki/index.php/GlueX_TOF_Meeting,_April_11,_2018#Minutes 
.

   -- Mark

___________________________


    GlueX TOF Meeting, April 11, 2018, Minutes

Present:

  * *FSU: * Sasha Ostrovidov
  * *JLab: * Thomas Britton, Mark Ito (chair), Simon Taylor, Beni Zihlmann

There is a recording of this meeting <https://bluejeans.com/s/yHTaf/> on 
the BlueJeans site. Use your JLab credentials.


      Review of minutes from the March 28 meeting

We went over the minutes 
<https://halldweb.jlab.org/wiki/index.php/GlueX_TOF_Meeting,_March_28,_2018#Minutes>. 


Sasha reported that he will finish the database of the tested PMTs soon.


      Calibration Status

Beni is starting to turn back to calibrations. Some runs done, but 
nothing new has been added to the database.

Going to an ADC read-out threshold of 160 has improved the efficiency, 
but not as much as he had hoped, although the efficiency for the 
half-width paddles has improved dramatically. Resolution may have 
suffered, but he has a suspicion that the increased width he sees in the 
global time distribution may be due to mis-calibration of individual 
channels.


      Amplified Base Prototype

Since changing the ADC threshold, analysis shows improvements for the 
prototype base channel. Individual PMT widths look better (after walk 
correction). There is a puzzle in that the comparison of mean-time 
distributions between the test paddle and a nearby 
part-of-the-regular-TOF paddle has the regular better paddle with better 
resolution.


      TOF threshold scan

Beni called our attention to the log entry 
<https://logbooks.jlab.org/entry/3558658> where he recorded the run 
numbers used the ADC-threshold/NSA scan done a couple of weeks ago. The 
thresholds were set at 150, 160, 170, and 180 ADC counts (160 is the new 
normal) and NSA was set, for each threshold, at 10 and 15. the data have 
yet to be analyzed.

Beni noted that 160 is still below the discriminator threshold applied 
on the TDC side. If a pulse height of 168 or lower is seen in the ADC, 
the corresponding TDC is generally absent.


      Action Item Recap

 1. Finish the PMT testing database. (Sasha)
 2. Finish calibration of the post-threshold-change data. (Beni)
 3. Analyze the ADC-threshold/NSA scan data.

Retrieved from 
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  * This page was last modified on 11 April 2018, at 11:01.

-- 
Mark Ito, marki at jlab.org, (757)269-5295

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