BCAL Reconstruction Meeting 2015-05-28
Video Conferencing Information
Meeting Time: 11:20 a.m. EDT
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Participant Direct Lines
- JLab Phone: in CC F326 is 757-269-6460 (usual room)
- JLab Phone in CC L207 is 757-269-7084
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- High priority items
- BCAL and FCAL z coordinates: some are referenced to the center of the target, not the global coordinate system.
- Low priority items
- z-coordinate determination from up/down amplitude ratio
- Sampling fraction tables
- Code Cleanup
- Action Items
- Commissioning Status Quo
- Effective speed (George)
- Time-walk corrections (Noemi)
- Layer efficiencies (Ahmed)
- Wavetrain code vs. single-energy code (Tegan)
- Shower curvature (Tegan)
- Any other business
Attendees: Elton, Will M., Mark D. (JLab), Christina, George (Athens), Noemi, Ahmed, Tegan, Zisis (Regina)
- Planned power outage at JLab in early June; after that crates will be turned off to save power, unless needed (notify Fernando).
- Magnet review will hopefully be done by the end of July, allowing ample time to ramp up the magnet for fall running.
- Action Items
- Elton reminded us of the urgency in reconciling the BCAL and FCAL coordinate system inconsistencies. This has been added to the 'Action Items' above and will be discuss with the FCAL folks next week.
- Commissioning Status Quo
- Effective speed (George): George has been working on the error implementation to see if it affects veff. He noticed some crazy points way off the 45 deg linear fit between z-track and z-point. These can be rejected for now, as their frequency is only about 1 out of every 100. z-track is assigned to the middle of a layer, and the error is estimated from the max between the z in the lower and upper boundary of the layer. The z-point errors are related to timing, shower extent, combination of channels, etc, and can be looked at in the future. For now, the spread in the points is a good enough estimator of the error. In the future, Simon can be contacted for information on the track error matrix, which would need to be propagated to the BCAL. George will investigate systematic errors and present results next week on veff and the timing offsets per channel.
- Time-walk corrections (Noemi): Noemi has been working on the time-walk correction method using simulated pulses from Elton's toy code. She has used different forms of the time walk formula. Elton pointed out that parameters have correlations and these are seen both in the 3-parameter fits and the 4-parameter ones. As long as the fits are good (check χ2) then we should use the min no of parameter in the fits. She is now ready to move to data analysis.
- Layer efficiencies (Ahmed): Ahmed is looking at the spring data runs (2931, 3027, etc). He has looked at the first 200 events in each run, seeking out abnormal points. Elton recommended that he look at the efficiency results, find unusual events, and then go to hdview2 to see these visually, using the -P EVENTS_TO_SKIP = xx command line flag.
- Cosmics: Andrei and Irina are working on comics analysis from fall and spring to improve the calibration constants. Tegan reported issues with the jcache command on fall runs. He will re-investigate and if the problem persists he will report back.
- Wavetrain code vs. single-energy code (Tegan): the mcsmear code was checked in yesterday as Shawn wanted to use it. Justin recommended that we run some bggen events and check the pi0 mean and width. Will suggested we use the BCAL pi0 plugin. Tegan will do this later today.
- Shower curvature (Tegan): Tegan and Andrei have been working on this. They see that in layer-4 more points are recovered in the curvature code than the IU one. In the other three layers, however, the curvature code returns less energy (by ~1/3). All cuts are same in both codes. Investigation continues. Will pointed out his log entry (https://logbooks.jlab.org/entry/3341906) which shows the effect (possibly not needed now) of non-linear corrections in z for the shower. The cluster energy looks more reasonable. Tegan will investigate this.
- Any other business:
- George asked for the paper recommended by Ryan Mitchell for tomorrow's journal club run by Matt. Zisis will provide it.