Precise Measurement of the π+ → e + v Branching Ratio

The PFN Collaboration is conducting a new measurement of the pi(1) -> e(+)nu branching ratio at the Paul Scherrer Institute, with the goal Uncertainty of, delta B/B-pi e2 = 5 x 10(-4) or lower. At present, the combined accuracy of all published pi e2 decay measurements lags behind the theoretical calculation by a factor of 40. In this contribution we report on the PEN detector configuration and its performance during two development runs done in 2007 and 2008.