CLAS Previous: Photon detection probability

Summary

We can briefly summarize the improvements concerned Cerenkov detector:

• The new radiator gas - perfluorobutane ( ) is chosen. It is shown that this gas improves significantly the electron detection efficiency and has reasonable pion rejection ( ).
• A new mirror is added to optimize the Cerenkov detector optics. It increases the number of detected photo-electrons and reduces the sensitivity to the deviation from the ideal mirror position.
• The Cerenkov detector optics is optimized for high and uniform electron detection efficiency.
• A procedure for the mirror alignment is developed. The sensitivity of the detection efficiency to the mirror position is investigated.
• Detection efficiencies for the the different particle types and energies are calculated.