Hans Dehmelt shared half of the 1989 Nobel Prize in Physics with Wolfgang Paul "for the development of the ion trap technique.” The other half of the prize was won by Norman F. Ramsey "for the invention of the separated oscillatory fields method and its use in the hydrogen maser and other atomic clocks." Hans Dehmelt, an atomic physicist, created the Penning trap, which traps a charged particle using static magnetic and electric fields. He studied properties of electrons by isolating an electron in a penning trap. The trap acts as a nucleus that the electron orbits around. This is then considered as a fake atom called geonium, whose energy levels can be determined. Using this, Dehmelt made precise measurements on characteristic quantities of the electron.