DESIGN OF A WATER COOLED EXTRACTION SYSTEM FOR A 55 KV, 22 A, 10 SEC HYDROGEN ION SOURCE

The design of a water cooled extraction system for a circular Periplasmatron is described. It is determined by the demand that the extraction system should fit into an existing glass insulator and that the ion optics should be adapted to the maximum current density available from the existing plasma source. From an electrode with a diameter of 175 mm, 22.7 A are expected at 55 kV. The 187 shaped extraction holes have an inner diameter of 7.85 mm. The extraction holes are completely surrounded by waterchannels having a minimum cross-section of 1.5 × 1.5 mm 2 . The water manifolds and feeds are integrated into the gridholders and the baseflange. A nearly force-free expansion of the grids is obtained by soft-spring-suspension of the grids. Assuming 2.5 % ob beam losses in each grid, the maximum temperature increase should not exceed 60 K, provided a ≤15 bar watersystem with appr. 6 m 3 /h is used for cooling.