Experimental study of electron-hadron separation in calorimeters using silicon diodes

Abstract The ZEUS group plans to install planes of large-area silicon diodes in depleted-uranium-scintillator calorimeters to separate electrons from hadrons in jets. This method was tested at 3, 5 and 9 GeV at CERN. Arrays of diodes were studied at depths between about 1 and 9 radiation lengths in a lead-scintillator calorimeter and in a simulated calorimeter consisting of depleted uranium and lucite. The e-h separation efficiency was measured for one and two planes of diodes as a function of depth in the calorimeter. A hadron misidentification of 2% at an electron efficiency of 90% was obtained with one plane of diodes. Addition of a second plane of diodes reduced the hadron misidentification to 0.3% with an electron efficiency of 90%. These results demonstrate that silicon diodes are excellent devices for e–h separation in a calorimeter.