USA As Represented by Secretary of the Navy

Richard F Fernsler

Scott G Walton

Robert A Meger

William E Amatucci

David N Walker

David D Blackwell

Darrin Leonhardt

David R Boris

Christopher D Cothran

Darrin Leenhardt

An apparatus and method for controlling electron flow within a plasma to produce a controlled electron beam is provided. A plasma is formed between a cathode and an acceleration anode. A control anode is connected to the plasma and to the acceleration anode via a switch. If the switch is open, the ions from the plasma flow to the cathode and plasma electrons flow to the acceleration anode. With the acceleration anode suitably transparent and negatively biased with a DC high voltage source, the electrons flowing from the plasma are accelerated to form an electron beam. If the switch is closed, the ions still flow to the cathode but the electrons flow to the control anode rather than the acceleration anode. Consequently, the electron beam is turned off, but the plasma is unaffected. By controlling the opening and closing of the switch, a controlled pulsed electron beam can be generated.

Apparatus and method for regulating the output of a plasma electron beam source

An apparatus and method for determining plasma parameters such as plasma electron density n. The probe apparatus includes an LC resonance probe comprising an inductive element and a capacitive element connected in series. The capacitive element of the probe can be in the form of a parallel plate capacitor, a cylindrical capacitor, a spherical capacitor, or any other suitable capacitor. The configuration of the probe apparatus gives it a characteristic resonance frequency &#x3c9;which can be determined by a circuit analysis device. When the capacitive element of the probe apparatus is placed in a plasma, the probe exhibits a new resonance frequency &#x3c9;, which is different from &#x3c9;because of the dielectric constant &#x2208; of the plasma. The difference in resonance frequencies can be used to determine plasma density n, where 

LC resonance probe for determining local plasma density

An rf probe is placed within a plasma and an rf signal from a network analyzer for a given dc bias voltage Vis applied The frequency applied by the network analyzer, &#x3c9;, is less than the plasma frequency, &#x3c9;, and therefore is not in the resonant absorption range (&#x3c9;=&#x3c9;) used to determine electron density in typical rf impedance probe operation. Bias voltages at the applied frequency are applied to the probe in a series of voltage steps in a range which includes the plasma potential. At each bias step, a value of Re(Z), the real part of the plasma's complex impedance, is returned by the analyzer. A local minimum in the real part of the impedance Re(Z) occurs where the applied bias voltage Vequals the plasma potential &#x3c6;. The plasma potential &#x3c6;can be found by taking the first derivative of Re(Z) with respect to Vp, and finding the value of Vp at which within error tolerances.

RF probe technique for determining plasma potential

An ion-ion plasma source, that features a processing chamber containing a large concentration of halogen or halogen-based gases. A second chamber is coupled to the processing chamber and features an electron source which produces a high energy electron beam. The high energy electron beam is injected into the processing chamber where it is shaped and confined by a means for shaping and confining the high energy electron beam. The high energy electron beam produced in the second chamber when injected into the processing chamber ionizes the halogen gas creating a dense, ion-ion plasma in the processing chamber that is continuous in time.

Time continuous ion-ion plasma

An ion-ion plasma source, that features a processing chamber containing a large concentration of halogen or halogen-based gases. A second chamber is coupled to the processing chamber and features an electron source which produces a high energy electron beam. The high energy electron beam is injected into the processing chamber where it is shaped and confined by a means for shaping and confining the high energy electron beam. The high energy electron beam produced in the second chamber when injected into the processing chamber ionizes the halogen gas creating a dense, ion-ion plasma in the processing chamber that is continuous in time. A method for creating an ion-ion plasma continuous in time.

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Annandale, VA, United States of America

Richard F Fernsler