The CHARM2 experiment at CERN studied the reaction e - e -

The CHARM2 experiment at CERN studied the reaction ν_μe^- → ν_μe^- using a ‘narrow band beam’ with mean energy 〈 E_νμ 〉= 24 GeV. The Super Proton Synchrotron provided two pulses Δt = 6 ms apart, with a cycle of T = 14.4 s. The useful mass of the target detector was M = 547 t, the side of its square useful cross-section was l = 3.2 m long. The target nuclei contained an equal number of protons and neutrons. What was the duty cycle (fraction of time in which interactions take place)? If we want to have an interaction every four pulses on average, how large a neutrino flux Φ is needed? How much intensity I? [Note σ/Ε_ν = 1.7 x 10^-45 m²/GeV.]