Experimental results and Monte Carlo simulations for a gadolinium atomic beam produced with a focused electron gun

The parameters of a beam of gadolinium atoms produced with focused 11 kV electrons were measured and their values compared with those obtained by Monte Carlo simulations. The net mass flow rate, the velocity and its standard deviation, the angular distribution and the population density of the ground and first four metastable states were measured by weight-loss, time-of-flight, deposition and laser resonance absorption methods. An atomic beam velocity of with a standard deviation of were obtained for a net flow rate of . The measured angular distributions are fitted by an equation of the form , where a and n are the distribution parameters and the angle with the vertical line. The atomic excitation temperature derived from the state distributions decreases with the flow rate to about 850 K for the highest flow rate. The simulations computed with the test-particle Monte Carlo (PTMC) code, including an electronic energy relaxation model, are in good agreement with the experimental values.