Scan Chamber

The Scan Chamber (horn or bucket) is a stainless steel chamber that is located at the bottom of the accelerator tube.  It is shaped as a triangle, flaring out from the top to allow room for the E-beam to be scanned to the required width.  The chamber and the accelerator tube must be kept at a very high vacuum. The bottom of the chamber where the beam exits is called the window, which is a very thin foil, made of titanium.  It is designed to be strong enough to maintain vacuum, however thin enough to allow the E-beam to pass through it.  High-speed air is used to cool the window.