November 20, 2013 Calibration
Meeting Time and Place
Wednesday November 20, 2013 at 11:00am At Jefferson Lab, the meeting will be held in F326
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- Status Update
- Scintillators for cosmics running - photos from Elton
- Alignment with straight tracks (Simon)
- BCAL constants
- Other systems
- CCDB Update (Mark)
Attending: Sean, Amiran (NU); Curtis, Naomi (CMU), Beni, Simon, David L., Lubomir, Mark (JLab), Zisis, Andrei (Regina)
- Status Update
- There was some discussion of adding scintillator paddles for cosmics running. Elton's photos showed enough room for paddles both below the magnet and between the magnet and the upper platform. CMU has several 6ft long paddles that they have been using, as well as an assortment of other sizes.
- There is also the option of using SiPMs instead of PMTs to read out the scintillators, if cosmics data is taken with the magnet on, but it is not clear if this is necessary.
- Simon showed some excellent progress in drift chamber alignment with straight tracks (magnet off), using a modified Kalman filter. Initial results for the CDC showed good qualitative agreement between thrown and reconstructed offsets, although there are several systematic effects still to be understood. The offsets in the x direction were found to be easier to determine than the y offsets. This may be partially due to the characteristics of the cosmic ray MC sample that was generated, but data taken with the photon beam (either with or without magnetic field) may be needed to determine the y offsets with better accuracy.
- Zisis gave some initial thoughts on the constants required for the BCAL. These include time offsets, and peak heights and widths. Many variables will also be stored in the online conditions DB. The plan is to have a list drawn up and in the DocDB within a week.
- Some of these constants are sensitive to run conditions and have been seen to drift in tests. These will need to be defined carefully so that the reconstruction code does not depend on access to the conditions database.
- CCDB Update
- Mark gave an update on the current status of the CCDB. The current code is stable and work is in progress on better documentation. There is a wish-list of new features to be added.