[Halld-pid] Start Counter Meeting Minutes, March 24, 2016

[Mark Ito]

...and Sean Dobbs was there too!

On 03/24/2016 12:22 PM, Mark Ito wrote:
> Folks,
>
> Please find the meeting minutes below and at http://tinyurl.com/hr5s9ym .
>
>   -- Mark
> ____________________________________________
>
>
>   GlueX Start Counter Meeting, March 24, 2016, Minutes
>
> The meeting came to order at 10:00 am.
>
> Present:
>
>   * *FIU*: Mahmoud Kamel, Eric Pooser
>   * *JLab*: Mark Ito (chair), Simon Taylor, Beni Zihlmann
>
>
>       Announcements
>
> Beam delivery to Hall D is scheduled for Sunday, March 27.
>
>
>       Reviewminutes from the last meeting
>       <https://halldweb.jlab.org/wiki/index.php/GlueX_Start_Counter_Meeting,_January_28,_2016#Minutes>
>
>   * No progress on the NIM paper or the TDR since the last meeting.
>
>
>       Calibration Update
>
> Mahmoud gave an update on time propagation delay calibration focusing 
> on a comparison between data and simulation. Seehis slides 
> <http://argus.phys.uregina.ca/cgi-bin/private/DocDB/ShowDocument?docid=2980>for 
> the plots and details.
>
> He showed the results of the calibration for each section of the start 
> counter for a sample of recent data (run 10496) and the sim1 simulated 
> data. Differences are seen mainly in the nose section, where fits do 
> not represent the data very well.
>
> The overall timing resolution is 270 ps for data, but 370 ps for 
> simulation. To start with for simulation, there is 300 ps of smearing 
> introduced by mcsmear but the reason for poorer resolution than that 
> is unclear. Mahmoud may try to go back to a simpler propagation delay 
> scheme that uses a constant velocity rather than the section dependent 
> velocity (straight/bend/nose) that is the current default.
>
>
>       Resolutions in mcsmear
>       <https://halldweb.jlab.org/wiki/index.php/Mcsmear_20160323#SC_Resolutions>
>
> Sean showed monitoring plots again comparing data and Monte Carlo. He 
> has collected a few interesting plots for other subsystems as well. 
> The start counter section shows a large number of RF-bucket 
> mis-identifications for simulation in the plots from which resolution 
> numbers are extracted. The reasons are not clear; RF bucket selection 
> for the data looks clean.
>
>
>       mcsmear parameters
>       <https://halldweb.jlab.org/wiki/index.php/Mcsmear_updates#START_COUNTER>
>
> We discussed the parameters used by mcsmear to introduce detector 
> effects to the start counter hits. The first line in the table is the 
> 300 ps mentioned in the discussion of Mahmoud's slides (above). Sean 
> proposed using the measured values of the resolution as recorded in 
> the CCDB to do time smearing with a channel-dependent width.
>
> We discussed how the other parameters should be measured and indeed 
> whether these are the best set of parameters to use. Mark and Simon 
> will make a proposal on how the various effects should be parametrized 
> and how those parameters should be measured. They will report back to 
> the group at a future meeting.
>
>
>       Multiple ADC hits checks
>
> Sean reminded us that now were are running with npeaks = 3 in the 
> FADC-250s and there is a need to study the matching of ADC and TDC 
> hits with this new scheme.
>
>
>       Efficiency measurement
>
> Paul Mattione had commented on Mahmoud's presentation of start counter 
> efficiency at theCalibration Meeting 
> <https://halldweb.jlab.org/wiki/index.php/March_9,_2016_Calibration#Minutes>. 
> There appears to have been some skepticism expressed due to the use of 
> protons to measure efficiency. Mahmoud pointed out the he gets the 
> same results independent of the particle species. We agreed to 
> circulate Paul's points and Mahmoud's response and discuss the issues 
> at the next meeting.
>
>
>       Run Issues
>
> There was one round of pedestal adjustment for the FADCs early in the 
> run by Eric and Sergey Furletov. Nothing has been done since. Beni 
> advocates doing another round before we start running again, and not 
> just for the start counter.
>
> The meeting adjourned at 11:05 am.
>
> Retrieved from 
> "https://halldweb.jlab.org/wiki/index.php?title=GlueX_Start_Counter_Meeting,_March_24,_2016&oldid=73947"
>
>   * This page was last modified on 24 March 2016, at 12:18.
>
>
> -- 
> marki at jlab.org, (757)269-5295
>
>
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-- 
marki at jlab.org, (757)269-5295

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