Using the 4X source performance and the Penning SPS scaling laws, we predicted the performance of the 8X source. A pulsed 8X source was then built and tested. After verifying the pulsed 8X source operation, especially the H−beam current, emittance, and power efficiency, we designed and built the CW 8X source. We plan to operate the source arc at dc power levels up to 30 kW. This will be accomplished by actively cooling the electrode surfaces with pressurized, hot water. The CW 8X source is presently undergoing shake‐down tests on a test stand at Los Alamos. Evaluation of the high‐current, hydrogen‐cesium dc arc will begin when these tests are completed.