 Complete the following phrase:  During World War II, the Germans had at least two projects, and the Japanese one, to create so-called death rays. One German project led by Ernst Schiebold concerned a particle accelerator with a steerable bundle of beryllium rods running through the vertical axis. The other was developed by Dr. Rolf Widerøe and is referred to in his biography. The machine developed by Widerøe was in the Dresden Plasma Physics laboratory in February 1945 