STATISTICS OF SECONDARY ELECTRONS FROM W INDUCED BY HE IONS AND ATOMS AT 0-DEGREES-90-DEGREES INCIDENCE

Secondary electrons from a W target, induced by 2 KeV He0 and He+ projectiles at 0° -90° angles of incidence have been measured for the first time using the statistics of secondary electron emission. The statistics were determined from the analysis of measured pulse height distribution spectra for 8-32 KeV He+ ions. The pulse height response of the detector is found to be sensitive to the applied bias to the detector. Its consequences in the interpretation of data are investigated. It was established that the number of electrons emitted per incident ion satisfy a Poisson distribution. Some new suggestions are made on the possible use of these results, in particular, on the role of the zeroth and the first Poisson coefficients, for surface studies. © 1990.