Digitizer Architecture Analysis for Target Diagnostics on the National Ignition Facility

This paper covers a systems engineering analysis of existing scope-based Target Diagnostics (TD) on the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL), for the purpose of selecting a standard digitizer architecture future diagnostics. Key performance criteria and a summary of test results are presented. Currently of the 60+ Target Diagnostics, at least fifteen use a type of high speed electrical signal data read-out device leading to over 200 digitization channels spread over six types of CRT and digital oscilloscopes, each with multiple models and versions. The proposed standard architecture discussed in this paper allows the NIF to efficiently and reliably operate digitizers that meet the required performance metrics for the lifetime of the NIF. The systems engineering analysis identifies key stakeholders for multiple subsets of scope-based diagnostics including but not limited to the nToFs (neutron Time of Flight), DANTE a broadband, time-resolved x-ray spectrometer, SPBT (South Pole Bang Time), GRH (Gamma Reaction History), and FFLEX (Filter Fluorescer Diagnostic). From these stakeholders, key performance metrics are derived and feed into test and evaluation criteria for different digitizers and architectures.