A Real-Time Multi-Function Digital Coincidence Spectrometer for Neutron Copper Activation Diagnostics.

Copper activation has been a standard diagnostic for measuring 14.1-MeV neutron yields in deuterium-tritium fusion experiments, which is essential to evaluate their performance for potential ignition in the future. Copper-activation equipment, especially data-acquisition systems, is updated constantly thanks to the rapid developments in electronics. Here, a multi-function digital coincidence spectrometer for neutron copper-activation diagnostics was developed. The digital pulse processing includes pulse shaping, multichannel pulse analysis, coincidence event picks, and coincidence multichannel time analysis were implemented on a single field-programmable gate array (FPGA) chip. The results demonstrate that the coincidence background is 0.013 counts per second. By using the multi-function digital coincidence spectrometer, the copper-activation diagnostics could be performed at the SG-III Laser facility when the neutron yield is ≥ 1.0 × 1010/hit.