Patent ID: 7790583

Claim:
An apparatus for cleaning a chamber of an electron beam treatment apparatus, the apparatus comprising: (a) a high voltage power supply coupled to an electron beam source for generating an electron beam current though a cleaning gas to energize the cleaning gas in the chamber of the electron beam treatment apparatus; (b) a current detector coupled to the high voltage power supply for monitoring a value corresponding to the electron beam current; (c) a pressure sensor coupled to the chamber that produces signals corresponding to a pressure of the cleaning gas in the chamber; (d) a real time controller that receives the signals from the pressure sensor and produces a substantially constant value of the electron beam current in response to the signals from the pressure sensor; and (e) a valve controller that receives the value from the current detector and the substantially constant value from the real time controller and is further coupled to a valve that controls the pressure of the cleaning gas in the chamber, wherein the valve controller controls the valve so as to adjust the pressure and thereby maintain the substantially constant value of the electron beam current, wherein the flow of cleaning gas is stopped when the cleaning gas pressure becomes substantially constant for a predetermined length of time.