High energy electrons (up to 30 MeV) have been measured in the self-modulated laser wakefield accelerator using a 2.5 TW laser pulse and a high sensitivity detector, a scintillator coupled to a photo-multiplier tube (PMT). Highly non-linear plasma waves have been detected using forward Raman scattering as a plasma diagnostic and a correlation between the non-linear plasma waves and electron signal has been observed.