[Halld-pid] Minutes, GlueX PID Meeting, Oct. 1

[Mark M. Ito]

  Find the minutes of the October 1, 2010 GlueX PID Meeting posted at 
http://www.jlab.org/Hall-D/software/wiki/index.php/GlueX_PID_Meeting%2C_October_1%2C_2010#Minutes 
and below as text.

GlueX PID Meeting, October 1, 2010
Minutes

Present:
* FSU: Sasha Ostrovidov
* JLab: Eugene Chudakov, Mark Ito (chair), Elton Smith, Sascha Somov,
Simon Taylor, Beni Zihlmann


TOF Prototype Studies

Sasha reported on progress at FSU.

Time Resolution

He has done new time resolution tests with the new Hamamatsu PMT's. To
do this back to use the CAEN constant-fraction discriminators. With the
new tubes at two voltages:
Voltage (V) Resolution (ps) Comment
1750 140 recommended voltage
2000 114 maximum voltage

Compare this to the previous best measurement with the old Hamamatsu
tubes at 2000 V of 124 ps. All resolutions quoted are for
(t[2]−t[1])/2.

These tests were done with Tyvek wrapping. When ESR was tried, at the
higher voltage, the resolution was 112, not much improvement. Tests
were also done with a 50-50 signal split. Resolution came out at 116
ps, very little effect. Using the new JLab leading edge discriminator,
without any time-walk correction, gives 180 ps.

Beni suggested that Sasha make an estimate of the PMT lifetime at
various voltages. He noted that lifetime is usually quoted by the
manufacturer in terms of total charge sourced by the tube.

They are using the new, triggered data acquisition system now. The next
step is to get the new lab room ready to accept the large trigger
paddle configuration.

Splitters

Fernando Barbosa has sent 2 splitters and 2 inverters to FSU for
testing. They have not arrived yet.

FSU MOU

Paul Eugenio sent us a new version of the MOU, incorporating language
suggested by FSU legal staff. Elton has prepared a new draft, with the
new language, and will send it along to Glenn Young and Allison Lung.

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