Interference suppression improvements of the UA1 electronics at the CERN Proton-Antiproton Collider

The UA1 experiment for investigations on proton-antiproton interactions has a detection unit comprising a cylindrical drift chamber, an electromagnetic calorimeter, a hadronic calorimeter and additional drift chambers for the muon detection. Especially with the em calorimeter the interference from nearby power circuits exceeded the specified level. The task for the author was to reduce the interference to an acceptable level without major infringement into the existing electronics. The causes and propagation paths of interferences were found out and simulated in the laboratory. An improvement strategy was derived consisting mainly in changes of the grounding configuration, the periferies of the electronics proper, and only to a small degree on the experiment electronics itself. The author developed a new current supply system featuring the same modularity as the detector itself enabling a nearly complete guard-shield configuration for the 12 channels of the same cable. The signal-to-noise ratio could be improved by 40 in the most afflicted channels. 44 refs., 32 figs., 5 tabs. (qui)