[Halld-pid] Time-of-Flight Meeting Minutes, April 14, 2015

[Mark Ito]

Folks,

Please find the minutes below and at

https://halldweb.jlab.org/wiki/index.php/GlueX_TOF_Meeting,_April_14,_2015#Minutes

   -- Mark
________________________________________________

GlueX TOF Meeting, April 14, 2015
Minutes

Present:

  * *FSU*: Hussein Al Ghoul, Brad Cannon, Sasha Ostrovidov, Aristeidis
    Tsaris
  * *JLab*: Eugene Chudakov, Mark Ito (chair), Simon Taylor, Beni Zihlmann


Calibration Status

Sasha showed a page <http://128.186.19.133/%7Eostrov/tof/20150414/> with 
a plot where he compares longitudinal position measured by end-to-end 
time differences in a chosen counter (one of the thin counters) with the 
known geometric position of counters in the other layer, where the 
counters are perpendicular to the chosen counter. Details of cuts and 
criteria are described on the page. There is a clear correlation in the 
position of the two measurement methods, but the plot is dominated by 
uncorrelated hits, with most of those coming from near the beam line, as 
expected.
There were several suggestions on how to over come this background.

Beni has a new approach to calibration that depends on starting by 
calibrating mean times and time differences and then transforming the 
results to constants to apply to individual channels. Simon is working 
on evaluating these new constants. Beni will give is a talk on his 
method at a future meeting.

TDC Time-Scale

Paul Mattione has discovered that our nominal setting of 25 ps for the 
time bin of the CAEN TDCs does not give the correct separation between 
successive RF timing pulses. He is seeing a time bin about 7% smaller.

Added in press: careful reading of the CAEN manual indicates a time bin 
width of 23.4375 consistent with what Paul found.

Meetings

Sasha Ostrovidov will start attending the Wednesday bi-weekly 
calibration meetings.

Mark will remind Paul about the upcoming Run Planning meeting on Thursday.

Retrieved from 
"https://halldweb.jlab.org/wiki/index.php?title=GlueX_TOF_Meeting,_April_14,_2015&oldid=66219"

  * This page was last modified on 15 April 2015, at 20:46.

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