[Halld-pid] Time-of-Flight Meeting Minutes, July 26, 2016

[Mark Ito]

Folks,

Please find the minutes below and at 
https://halldweb.jlab.org/wiki/index.php/GlueX_TOF_Meeting,_July_26,_2016#Minutes 
.

   -- Mark

_____________________________


    GlueX TOF Meeting, July 26, 2016, Minutes

Present:

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

There is a recording of this meeting <https://bluejeans.com/s/a2@C/> on 
the BlueJeans site.


      Review of minutes from the previous meeting

We went over the minutes from July 19 
<https://halldweb.jlab.org/wiki/index.php/GlueX_TOF_Meeting,_July_19,_2016#Minutes>. 
No significant comments.


      PMT order

Ardavan Ghassemi of Hamamatsu sent us an email 
<http://www.jlab.org/Hall-D/gluex_secure/procurements/TOF_PMT/ardavan_2016-07-22.pdf> 
cautioning us that the current PMT model used in the TOF will be 
discontinued as some point soon. He proposes a replacement model and 
sent along a data sheet for the R13435 
<http://www.jlab.org/Hall-D/gluex_secure/procurements/TOF_PMT/R13435%20Tentative%20Data%20Sheet%2020150527.pdf>. 
The new tube has a diameter about 1 mm greater than the old.


      Cosmic data

Beni led us through his plots:

  * looking at signal amplitude vs time difference for 1350V Amp vs dt
    1350V paddle11 plane2.jpg
    <https://halldweb.jlab.org/wiki/index.php/File:Amp_vs_dt_1350V_paddle11_plane2.jpg>
    Amp vs dt 1350V paddle11 plane2 zoom.jpg
    <https://halldweb.jlab.org/wiki/index.php/File:Amp_vs_dt_1350V_paddle11_plane2_zoom.jpg>
  * The flash250 ADC op-amp signal inverting input causes a baseline
    shift that feeds back to the input to the leading edge discriminator
    resulting in a miss match between threshold setting and actual
    threshold.
  * other examples of amplitude vs dt paddle 18 plane 1: Amp vs dt 1350V
    paddle18 plane1.jpg
    <https://halldweb.jlab.org/wiki/index.php/File:Amp_vs_dt_1350V_paddle18_plane1.jpg>
  * or paddle 20 plane 1: Amp vs dt 1350V paddle20 plane1.jpg
    <https://halldweb.jlab.org/wiki/index.php/File:Amp_vs_dt_1350V_paddle20_plane1.jpg>
  * or paddle 20 plane 2: Amp vs dt 1350V paddle20 plane2.jpg
    <https://halldweb.jlab.org/wiki/index.php/File:Amp_vs_dt_1350V_paddle20_plane2.jpg>
  * and the same PMT but 100V higher at 1450V: Amp vs dt 1450V paddle20
    plane2.jpg
    <https://halldweb.jlab.org/wiki/index.php/File:Amp_vs_dt_1450V_paddle20_plane2.jpg>

The DC shift in the baseline at the discriminator from the FADC can be 
as much as 35 mV and depends on the FADC channel. We will need to have 
channel-by-channel discriminator settings, especially when running the 
tubes at lower gain.

The next step is to try and look at time resolution at new reduced 
voltages.


      Next Meeting

We will meet again in a week.

Retrieved from 
"https://halldweb.jlab.org/wiki/index.php?title=GlueX_TOF_Meeting,_July_26,_2016&oldid=76574"

  * This page was last modified on 28 July 2016, at 16:42.

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

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://mailman.jlab.org/pipermail/halld-pid/attachments/20160728/e9a134c6/attachment-0001.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: 300px-Amp_vs_dt_1350V_paddle11_plane2.jpg
Type: image/jpeg
Size: 13234 bytes
Desc: not available
URL: <https://mailman.jlab.org/pipermail/halld-pid/attachments/20160728/e9a134c6/attachment-0006.jpg>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: 300px-Amp_vs_dt_1350V_paddle11_plane2_zoom.jpg
Type: image/jpeg
Size: 12846 bytes
Desc: not available
URL: <https://mailman.jlab.org/pipermail/halld-pid/attachments/20160728/e9a134c6/attachment-0007.jpg>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: 300px-Amp_vs_dt_1350V_paddle18_plane1.jpg
Type: image/jpeg
Size: 13955 bytes
Desc: not available
URL: <https://mailman.jlab.org/pipermail/halld-pid/attachments/20160728/e9a134c6/attachment-0008.jpg>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: 300px-Amp_vs_dt_1350V_paddle20_plane1.jpg
Type: image/jpeg
Size: 11722 bytes
Desc: not available
URL: <https://mailman.jlab.org/pipermail/halld-pid/attachments/20160728/e9a134c6/attachment-0009.jpg>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: 300px-Amp_vs_dt_1350V_paddle20_plane2.jpg
Type: image/jpeg
Size: 12132 bytes
Desc: not available
URL: <https://mailman.jlab.org/pipermail/halld-pid/attachments/20160728/e9a134c6/attachment-0010.jpg>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: 300px-Amp_vs_dt_1450V_paddle20_plane2.jpg
Type: image/jpeg
Size: 11533 bytes
Desc: not available
URL: <https://mailman.jlab.org/pipermail/halld-pid/attachments/20160728/e9a134c6/attachment-0011.jpg>