Scintillator-strip/WLS-fiber EM shower maximum detectors in the CDF plug upgrade

A number of different electromagnetic shower maximum detectors are tested. The performance of a design foreseeing long scintillator strips with wavelength shifting fibers embedded in them and readout by a multichannel photomultiplier tube (PMT) is investigated. An X-Y detector providing two orthogonal views of an EM shower from the same piece of scintillator is studied. Results from bench tests as well as beam tests are reported. Good performance and position resolution are found. The different sources of possible crosstalk among the individual channels are examined. Good agreement is obtained with the EGS Monte Carlo for the EM lateral shower shape at the shower maximum position. Calibration issues are investigated