Abstract
Distributions of energy fluence with respect to energy were measured by three methods for x-rays produced in a tungsten target tube with a 1 mm beryllium window. The tube was energized by a constant potential generator operated at 15, 20, 25 and 30 kv. The methods used were gas proportional counting, scintillation counting and attenuation analysis. The percentage of the total energy fluence due to tungsten L-characteristic radiation was measured by each of the above techniques and also by using balanced (Ross) filters. It reached a maximum of about 33%. The methods gave results which were in reasonable agreement with one another and with theory.