the babar cherenkov detector detection of internally reflected cherenkov yuen-jung chang
DESCRIPTION
DIRCTRANSCRIPT
The Babar Cherenkov DetectorDetection of Internally Reflected
Cherenkov
Yuen-Jung Chang
Cherenkov radiation Charge particle passes through an insulator at a constant speed greater than the speed of light in that
medium. The charged particles polarize the molecules of that medium, which then turn back rapidly to their
ground state, emitting prompt radiation
cos θ = 1/βn
DIRC
DIRC
Quartz BarsMaterial is actually synthetic fused silica (n = 1.473 )Cross section 17.25 mm x 35.0 mm.Four 1.225 m long bars glued together make one 4.9 m long DIRC bar.DIRC uses as a radiator 144 quartz bars arranged in a 12-sided polygon around the beam line
Photomultipliers (PMT)