Patent Number: 
Section: claims

1. An exit window for an electron beam from a linear electron accelerator for use in producing radioisotopes comprising:a cylindrical channel operatively connectable at one end to a vacuum Chamber configured for travel of the electron beam, Which has a Gaussian profile and peak flux approximately centered on a centerline of the electron beam; anda domed dished head at the other end of the channel, the domed dished head comprising a convex portion comprising two or more distinct convex radii and a concave portion comprising two or more distinct concave radii that differ from the two or more convex radii, wherein the two or more convex radii and the two or more concave radii provide for a gradual thickening of the window from a centerline of the exit window to the channel, allowing the domed dished head to resist pressure stress created by cooling medium circulating around a protruding crown of the domed dished head and the vacuum in the cylindrical channel and to maintain a combination of thermal stress and the pressure stress below the fatigue limit of the material forming the exit window. 2. The exit window of claim 1 wherein the protruding crown has a circular or oval shape. 3. The exit window of claim 1 wherein the exit window is a single integral piece. 4. The exit window claim 1 wherein the exit window comprises beryllium, copper, steel, stainless steel, titanium, alloys of any of the foregoing, or a combination of any of the foregoing. 5. The exit window of claim 1 wherein the exit window comprises Ti-6Al-4AV. 6. The exit window of claim 1 wherein the window is removably mountable to a window flange. 7. The exit window of claim 1 wherein the exit window has a thickness ranging from 0.15 mm to 0.75 mm. 8. The exit window of claim 1 wherein the exit window is shaped to fit into a converter target holder. 9. The exit window of claim 1 wherein the exit window is shaped to fit into a production target cooling tube. 10. The exit window of claim 1 wherein the exit window comprises two or more fastener channels to allow the exit window to be mountable to a mating flange of a converter target holder utilizing a knife edge vacuum sealing method. 11. The exit window of claim 1 wherein the exit window comprises two or more fastener channels to allow the exit window to be mountable to a converter target holder utilizing welding or brazing techniques.