Status of the Cerenkov detector calibrations and efficiency analysis.

To do :

• Calibrations
  
  • Amplitude calibrations.
    • Pedestal calibrations.
      Partially done. Needed to get more calibrations (once per one - two weeks or so)
    • One photoelectron calibrations CC_CALIB
      Partially done. Needed to get more calibrations (once per one - two weeks or so)
    • Nphe estimate using the dependence of the mean amplitude and its dispersion in the PMT.
      In progress. Have a problem there.
      Needs to pay some more attention.
  • Time calibrations
    • T1 calibrations
      In progress. One calibration file was written, but... it seems that it is not good. Attempt to analyze it shows only zeros. Most probably we'll need more TDC_calib runs made, and need to analyze them. The problem is that the hardware is NEW, and we CAN NOT use old values for T1.
    • T0 calibrations
      In progress. At least the program is ready, one attempt was made to analyze data and find constants. The problem is with RF time, which is totally wrong. Need to made TOF calibrations first.
  • Efficiency
    • The NEW "CC plane" calculation, comparing to the OLD one.
      Done. The PMT positions are close, so we can use either "CC plane", The estimated difference is ~1 degree in Theta and no difference in Phy.
      
    • fiducial cuts
      • Compare the Theta_p - Phy_p plots for the number of photoelectrons and efficiency for different initial energies / magnetic fields.
        1.3 GeV and 3.0 GeV plots for the number of photoelectrons compared. No difference seen, what makes possible to apply the same cut for any energy.
        
        
        
    • Electron selection for events without CC in the trigger.

      In progress. 1.3 data analysis started. First results shows that the Sector 6 efficiency in the physical region at Theta_p up to 35 degrees is rather good, - not less than 98% Need more statistics and some more cuts for electron selection.

    • Pion to electron rejection estimate. In progress (very beginning). Estimated number of particles in sector 6 with EC_ONLY trigger in the sample of about 2.5*10^8 events:
      pi plus : 4500
      pi minus : 250
      protons : 1000