Rich G.
Ion source A energized alone. Source A produces 10mA discharge current with 5mA appearing on the main HV power supply. Note the triangular shaped beam visible in the center where the beam converges and density is highest. The focal point appears to be just past the center of the ring acceleration grids. Since all the grids are based on concentric circles the focal point should occur in the center. The fact that it is not centered implies some optical effect not taken into account in the optical design or the construction.
Ion source B energized alone. 10mA source discharge current with 5mA appearing on the main HV power supply.
Ion source C energized alone. 10mA source discharge current with 5mA appearing on the main HV power supply.
Ion sources A,B and C energized. Each ion source has a 10mA discharge current and the main HV power supply is delivering a current equal to the sum of the three sources or about 15mA. The main negative HV supply was set at -30kV. It is interesting to note that the three beams become visible on the opposite side of the bright convergence point at the center of the acceleration grids. This is where the beam focus is smallest and of highest density. This last photo includes a piece of leaded X-ray glass placed in front of the camera lens. The previous images had no leaded X-ray glass and contain X-ray generated noise in the CCD array.
