Electron beam emitter

1. An exit window for an electron beam emitter through which electrons pass in an electron beam, the exit window comprising:

a support plate for supporting the exit window, the support plate having a first series of holes therethrough; and

a first window layer extending adjacent to the support plate and including a foil having a second series of holes therethrough;

wherein at least one hole of the first series of holes is aligned with multiple holes of the second series of holes.

2. The exit window of claim 1 , wherein each hole of the first series of holes is aligned with multiple holes of the second series of holes.

3. The exit window of claim 1 , wherein at least one hole of the second series of holes is blocked by a portion of the support plate.

4. The exit window of claim 1 , wherein at least one hole of the second series of holes is partially blocked by a portion of the support plate.

5. The exit window of claim 1 , wherein a portion of the first window layer is maintained across at least one hole of the first series of holes.

6. The exit window of claim 1 , wherein a portion of the first window layer is arranged to provide structural strength for the exit window.

7. The exit window of claim 1 , wherein the size of each hole of the first series of holes between about 0.050 to 0.200 inches.

8. The exit window of claim 1 , wherein the size of each hole of the second series of holes is between about 0.040 to 0.100 inches.

9. The exit window of claim 1 , wherein the first window layer foil includes a material selected from the group consisting of titanium, beryllium, aluminum, stainless steel, copper, gold and silver.

10. The exit window of claim 1 , the support plate and first window layer being bonded together.

11. The exit window of claim 10 , the support plate and first window layer being at least one of welded and brazed together.

12. The exit window of claim 1 , comprising a second window layer extending adjacent to the first window layer, said second window layer extending adjacent to second series of holes and providing thinner window regions which allow easier passage of the electrons through the exit window.

13. A method of forming an exit window for an electron beam emitter through which electrons pass in an electron beam comprising:

providing a support plate for supporting the exit window, the support plate having a first series of holes therethrough;

providing a first window layer extending adjacent to the support plate and including a foil having a second series of holes therethrough; and

aligning at least one hole of the first series of holes with multiple holes of the second series of holes.

14. The method of claim 13 , comprising aligning each hole of the first series of holes with multiple holes of the second series of holes.

15. The method of claim 13 , comprising aligning the support plate with the first window layer such that at least one hole of the second series of holes is blocked by a portion of the support plate.

16. The method of claim 13 , comprising aligning the support plate with the first window layer such that at least one hole of the second series of holes is partially blocked by a portion of the support plate.

17. The method of claim 13 , wherein the first window layer foil includes a material selected from the group consisting of titanium, beryllium, aluminum, stainless steel, copper, gold and silver.

18. The method of claim 13 , comprising bonding the support plate with the first window layer.

19. The method of claim 18 , wherein bonding includes at least one of welding and brazing.

20. The method of claim 13 , comprising providing a second window layer extending adjacent to the first window layer and aligning the second window layer with the second series of holes to provide thinner window regions which allow easier passage of the electrons through the exit window.