| 摘要 |
A charged particle propagation apparatus comprising a generator comprising a vacuum chamber with a gun therein for discharging a charged particle beam from within the vacuum chamber and out of the vacuum chamber through a beam exit disposed in a wall of the vacuum chamber. The apparatus further comprises a higher pressure region adjoining the vacuum chamber at the beam exit that is maintainable at a pressure greater than a pressure of the vacuum chamber and a plasma interface disposed at the beam exit comprising a plasma channel. The plasma channel is aligned with the beam exit, has a first end and a second end and has at least three electrode plates disposed between the first end and the second end. The apparatus further comprises a control system adapted to apply a sequence of electrical currents to the electrode plates. The sequence of electrical currents is configured to cause at least one plasma to move from the first end to the second end of the plasma channel thereby pumping down the beam exit, and, in use, the charged particle beam is propagated from the vacuum chamber through the, or each, plasma in the plasma channel and into the higher pressure region. |
