AUTOMATIC ALIGNMENT OF THE ADVANCED RADIOGRAPHIC CAPABILITY FOR THE NATIONAL IGNITION FACILITY

Experiments and operation of the National Ignition Facility (NIF) will soon benefit from a new, high-energy x-ray (60 – 200 keV), radiography diagnostic [1]. To generate these x-rays, in the summer of 2014, NIF will be deploying the Advanced Radiographic Capability (ARC) which is designed to generate precise, high-energy shortpulses, amplified through a NIF beamline, and aimed at backlighter filaments near ignition targets. The alignment precision for ARC is an important element in the success of this enhancement. A key challenge for the ARC automatic alignment (AA) process lies in implementing the new alignment capabilities without disturbing the existing operations of NIF. Any risks that may occur by the addition of the ARC system are mitigated through careful design and control of the ARC/AA interfaces. In this paper, we will describe some of the new ARC alignments, the ARC Split Beam Injector (SBI) and ARC Compressor. The SBI combines two independent ARC beams into a single NIF beam before being aligned and injected into the main NIF amplifier chain. After main amplification, the pulsewidths are compressed in the ARC compressor vessel and aimed at backlighter targets in the NIF target chamber. Alignment verification of the compressor grating will be critical to ensuring the ARC pulses meet their design specifications.