Results from the ICARUS T 600 module

We have studied the µ decay energy spectrum from a sample of stopping µ events acquired during the test run of the ICARUS T600 prototype. This detector allows the spatial reconstruction of the events with fine granularity, hence the precise measurement of the µ range and dE/dx with high sampling rate. This information is used to compute the correction factors needed for the calorimetric reconstruction. The Michel ρ parameter is then measured by comparison of the experimental and Monte Carlo simulated µ decay spectra, obtaining ρ = 0.72 ± 0.06 (stat.) ± 0.08 (syst.).