Study of position and angular resolution for electron showers measured with the electromagnetic SiW prototype

Electron data collected in the 2006 CERN beam test were used to evaluate the position and angular resolution of the SiW electromagnetic calorimeter. The angular resolution was evaluated to be (106±2/$\sqrt{E(GeV})⊕ 0.004±0.001) mrad along x and (100±2/$\sqrt{E(GeV})⊕0.014±0.001) mrad in the y direction. The resolution along the x axis was better than along the y axis due to the staggering of layers in the x direction. The upper bound on the position resolution was evaluated after correcting for the calorimeter cell structure. This limit is due to the contribution of the tracking system to the position resolution. The results were (15.7 ± 0.2/E ⊕ 0 ± 0.4/E ⊕ 1.04 ± 0.01) mm and (15.3 ± 0.5/E ⊕ 1.4 ± 0.6/√E ⊕ 0.94 ± 0.02) mm for the x and y axis respectively.