Now that the deuterium lamp is enriched with electrons the strike circuit initializes. A fairly high voltage in excess of 400 V is applied to the Anode, see Fig 4. This voltage creates an arc and lamp emission begins. The anode voltage can then be lowered to approximately 60-70V and often the cathode voltage can also be reduced, the arc will now help to supply electrons for continued emission. The deuterium lamp now has three regions glowing, see Fig 5. The areas on both sides of the aperture contribute to useful light. However the cathode glow is not used as it is unstable. The cathode glow is masked with a metal shield around the lamp. The shield has a cut out to allow light out. Fig 6 depicts this in a simplified distorted side view. The shield is also fully opaque, while Fig 6 is translucent for simplicity. Fig 7 shows a front view with the aperture and shield aligned correctly and with a fully opaque shield.
More to come..