Ultrafast photoconductive detectors for burn time and bang time measurements on Phebus

To study deuterium‐tritium mixture implosion conditions on laser fusion experiments, we developed very high‐speed photoconductive devices. The targets are irradiated by the 1.3‐ns, 5‐kJ blue light of the two beams of the Phebus laser. The neutron yield is a few 1010/4π. Some neutron sensitivity measurement results are presented on neutron‐damaged GaAs and diamond. These devices are able to measure the time behavior of the thermonuclear neutron burst. So, we have measured the burn time and the bang time on direct drive experiments with 100 ps as accuracy.