XGT1 2018 analysis

X>1 Current Tasks

Data Calibrations Checks

Pass-4 write-up and overview of changes

• Pass-4 implements default pedestals, which recover a significant number of X>1 events. This was straight forward, so everything should be set up correctly
  • PS was high.
  • Data rate was quite high.
  • New ADC-TDC offset sent to each detector, (starttime-pulsetime-offset) -> New timing windows (Done)
• Pass-4 reduce tof_tolerance value from 100 to 5 (ns)
  • This was a problem with F2 data analysis. We need to look at the new hodo starttime histograms and see if there are any patterns / trends /

differences. I haven't looked at them yet.

"Also the hodoscope has been changed so that it should find a selection of good hodoscope hits that made the trigger for every event. But also the hodoscope code has changed so that finding a good starttime from these good hodoscope hits is more selective. As the rate goes up the probability of the singles trigger being formed from a random coincidence of say something passing through X1 and Y1 (which are close together) with a random in X2 or Y2 ( or vice versa) increases. The code tries to reject the random triggers by looking for peak in the timing of the good hodoscope hits with a window set by the parameter tof_tolerance. One needs to check that this parameter is set to a reasonable value of 3- to 5ns. It needs to be study to determine reasonable value. If this is set properly, then I would say that one wants to reject events which the code could not find a good starttime (in the code P.hod.goodstarttime = 0 for bad events , =1 for good events)."

[New Hodo Histo Diagnostics] [Changes other Detectors]

Unsolvable issues for sp18 data

100ns deadtime of the FADC (later changed to 50ns)

"The other issue is the with the reference time. This has multiple issues. One is that the FADC and TDC have different deadtime so they can each pick a different reference time pulse which is rate dependent. Also since the reference time is a train of up to 3 pulses ( depending on the event) for the spring18. The effect is that a previous 3/4 hodo that is not accepted as the trigger ( for singles this would be because of computer deadtime) has the ELREAL or ELCLEAN pulse taken a the good reference time instead of the 3/4hodo that was accepted as the trigger. I looked at coincidence runs in the fall18 when the reference time was a 'train" of only two pulses. So the reference time issue manifest themselves differently.

I made new variable of the reference time used for each detector and variable of the difference between the chosen reference time and an earlier reference time pulse so that cuts could in principal be place on these variables to select event which pass good reference time cuts (combination of acceptance region in the reference time for hodoscope,DC and FADC and an anti-cut on the time difference) and then keep track of the events which are missed to correct the data for the events that are cut out. "

Beam in hcana

• Pointing Surveys use inconsistent language
  • I just don't have a good imagination for the coordinates yet (2 years later..)
    • Go sit under the pivot with a piece of paper and pencil
• HARP scan fits are not those reported -> Fits used with no documentation / fit pannel
  • I am always confused by the change of coordinates between different systems.
  • Leads to some differences in gbeam.param values

Review hallc_replay_XEM

• In progress (check_master branch).
  • Get up and running with the XEM replay. Some small difference in directory structures compared to f2xem and hallc_replay_f2xem (yes, two others!)
  • Added updated hallc_replay calibration scripts.