Abstract
The doubly differential K ionisation cross section of Ag and Au was measured for electron impact as a function of outgoing electron energy at a fixed scattering angle of 20 degrees . The incident electron energy was 300 keV. Coincidences between characteristic K X-rays and outgoing electrons are used to isolate the K ionisation process. The results are compared with calculations of Das (1972) and of Das and Konar (1974).