Longitudinal cathode expansion in an ion source

An ion source design and manufacturing techniques allows longitudinal cathode expansion along the length of the anode layer source (ALS). Cathode covers are used to secure the cathode plates to the source body assembly of an ion source. The cathode covers allow the cathode plate to expand along the longitudinal axis of the ion source, thereby relieving the stress introduced by differential thermal expansion. In addition, the cathode cover configuration allows for less expensive cathode plates, including modular cathode plates. Such plates can be adjusted relative to the cathode-cathode gap to prolong the life of a given cathode plate and maintain source performance requirements. A cathode plate in a linear section of an ion source has symmetrical edges and can, therefore, be flipped over to exchange the first (worn) cathode edge with the second (unworn) cathode edge.