Large area source for uniform electron beam generation

An electron beam apparatus, comprising:

• a vacuum chamber, wherein an interior portion of the vacuum chamber is one of bead blasted, roughened, anodized or darkened;
• a large-area cathode disposed in the vacuum chamber;
• a first power supply connected to the cathode, wherein the first power supply is configured to apply a negative voltage to the cathode sufficient to cause the cathode to emit electrons toward a substrate disposed in the vacuum chamber;
• an anode freely positioned between the large-area cathode and the substrate on an inwardly projecting shelf;
• and
• a second power supply connected to the anode, wherein the second power supply is configured to apply a voltage to the anode that is positive relative to the voltage applied to the cathode.

An electron beam apparatus, comprising:

• a vacuum chamber;
• a large-area cathode disposed in the vacuum chamber;
• a first power supply connected to the cathode, wherein the first power supply is configured to apply a negative voltage to the cathode sufficient to cause the cathode to emit electrons toward a substrate disposed in the vacuum chamber;
• an anode placed between the large-area cathode and the substrate;
• an electrically isolated shelf disposed in the vacuum chamber, wherein the shelf defines a surface on which the anode is placed is inwardly projecting and;
• and
• a second power supply connected to the anode, wherein the second power supply is configured to apply a voltage to the anode that is positive relative to the voltage applied to the cathode.