A new by developed high resolution fast electron-energy-loss coincidence spectrometer was described. It consists of high resolution fast electron-energy-loss spectrometer

positive ion time-of-flight mass spectrometer

negative ion time-of-flight mass spectrometer

the corresponding electronics and data acquisition system. Using this apparatus

the scattered electrons

the ionized or dissociated positive ions

the dissociated negative ions or ionized electrons produced from the electron impact with atom or molecule can be measured simultaneously. The photoionization efficiency curve and the partial optical oscillator strength densities for different fragments of CO was determined by this work.