In-situ measurement and self-calibration system for high-power laser energy in ICF facilities

Precise real-time measurement of high-power laser energy is the foundation for ICF facilities to keep power and energy balance, which requires energy measurement equipment to maintain considerable linearity during a long operation period. The measurement accuracy, efficiency and calibration procedure stability were the key factors for ICF facilities' operation. This work proposed a new thermopile-type energy meter and calibration system to achieve high-precise in-situ measurement and calibrating of high-power laser energy. The study suggested that the thermal energy conversion, electric energy loading and metering, heat transfer, sensor temperature rise, sampling circuit and post-processing significantly affected the high-power laser energy measurement and calibration results. Besides, the whole numerical modeling process was established and verified by experiments on the energy transfer and physical quantity conversion process in energy measurement. The laser energy measurement and calibration system has self-calibration functions and stable operation through numerical simulation and optimization of the key factors. This study is of great significance for the high-power laser energy monitoring and output energy improvement of ICF facilities, broadening the method for the high-precision in-situ measurement system.