Laser backscatter damage risk assessments of NIF Target Experiments

The National Ignition Facility (NIF) performs target experiments of many types. Laser power and target configurations and materials vary between experiments; in many cases the variation is incremental from a previously fielded experiment but can also involve a major change that represents a new operating regime for laser plasma interactions with a large plasma. A review methodology has been established to assess the potential risk of damage to the facility optics from scattered light for all proposed experiments. This process uses a defined set of rules and criteria to efficiently assess the risks of each proposed experiment. This assessment allows rapid approval of most experiments and identifies others that need more detailed analysis and/or modifications to their design to produce acceptable risk. The methodology uses comparisons to an extensive data base of existing experiments and some simple rules to extend beyond the parameters for which we have data. This poster will describe our assessment methodology and data sets that provide the experimental basis.