While the blue light focuses inside tiny holes at the ends of the cylindrical target, or hohlraum, and heat its inside, the green light focuses beyond the target and illuminates the target, the stalk supporting it, and three instruments located less than two inches away, for a brief instant before the target vaporizes. Simultaneously x-rays from the target have ablated material from the surfaces of the instruments. When this ablation debris begins to encounter high velocity target debris, it is heated enough to emit light. The target and ablation debris end up depositing on surfaces around the inside of the target chamber. Numerous instruments inside the target chamber point at the location where the target positioner would suspend an ICF target.
Laser light enters the chamber through two conical rings of five beam ports.
On the opposite side of the target chamber beam dumps absorb the green light which focuses past the target. A round rail, below a circular handrail in the bottom of the target chamber, shows a clear interface between the portion shielded from target x rays by the handrail above, and the part maintained clean by x-ray ablation. Instrument cabling inside the chamber casts an artificial shadow on the target chamber wall, providing a shaded region where target and ablation debris can accumulate without being remobilized by target x-rays. This observation led to the current design for the National Ignition Facility target chamber, where angled louvers will be attached to panels on the target chamber wall, so that material mobilized from the louver surfaces will deposit primarily on the back sides of adjacent louvers, rather than escaping into the target chamber.