Fusion burn width measurements and trends in high performing inertial confinement fusion experiments

In Inertial Confinement Fusion (ICF) deuterium-tritium (DT) fusion reaction rates are an important measurement providing crucial performance parameters for implosion experiments (shots) such as fusion bang time and fusion burn width. With increasing performance at the National Ignition Facility (NIF) fusion burn width is getting shorter and dropping below 100 ps. Gas Cherenkov Detector (GCD) performs energy-thresholded measurements of the DT fusion reaction rate. However, state-of-the-art photomultiplier tubes (PMT) limits the temporal resolution to ~100 ps, making shot-to-shot performance hard to differentiate at narrow burn width. The Pulse Dilation – PMT (PD-PMT) makes measurements at a temporal resolution of 10 ps possible. Unfortunately, x-ray or neutron-induced gamma backgrounds corrupted the burn width measurements performed and clean data could not be produced. Recent improvements overcome this issue and high temporal resolution DT fusion burn rates are possible on high yield shots at NIF. First results - including a record yield shot at NIF – and performance trends are presented. The shapes of the DT gamma reaction history can be compared with simulation results for the first time.