Author/Authors :
Akhmetshin، نويسنده , , R and Wang، نويسنده , , M.Z and Guo، نويسنده , , R.S and Huang، نويسنده , , H.C and Lu، نويسنده , , R.S and Tsai، نويسنده , , K.L and Ueno، نويسنده , , K and Wang، نويسنده , , C.H. and Chou، نويسنده , , F.I and Wei، نويسنده , , Y.Y and Hou، نويسنده , , W.S، نويسنده ,
Abstract :
We check the scintillation light yield of all BGO crystals used for the Extreme Forward Calorimeter (EFC) at BELLE. The percentage spread of the distribution is only 6%. The nonuniformity of the light yields measured lengthwise for the forward EFC is close to 13% and is ∼0% for the backward EFC. The test crystals, two per ingot, from mass-production are subjected to the radiation hardness test. The results obtained at BINP and NTU are in good agreement. Some EFC crystals, selected randomly, show the light yields drop about 25–50% after receiving 1 krad dose and remain stable afterwards. There is little sensitivity to the rate that the 1 krad dose is received, since the recovery process is very slow, in the order of days to weeks.
