High Enery Electromagnetic Shower Position Measurement by a Fine Grained Scintillation Hodoscope

We have measured the centroids of high energy electromagnetic showers initiated by positrons in the energy range 2 to 17.5 GeV with a fine grained scintillation hodoscope composed of seven 1 cm wide elements placed behind a 3.6 radiation length (15 cm) converter composed of SCG1-C scintillation glass. A simple first moment calculation using the ionization observed in each element of this hodoscope yields a shower position resolution as a function of energy of: ±(mm) √ 0.7 ± 5.6/√E(GeV). We present results on the energy dependence of the shower profiles and the ionization measured by this hodoscope.