抄録
The liquid mercury target system for the MW-class pulse spallation neutron source was installed at the material and life science experimental facility (MLF) in J-PARC. The laser Doppler vibrometer system was installed as diagnostic system on the structural integrity of the mercury target. Vibration measurements on the liquid mercury target vessel were carried out using this system. The amplitude of the first peak increase with an increase of the proton beam power. The delay time until the vibration starts in experimental results is longer than in analytical results. The slope of the regression line indicating the relationship between the delay time and the injection position of the proton beam is higher than that estimated by the sound velocity of the mercury. That is, the sound velocity of the mercury in the mercury vessel is predicted to be lower than that calculated using material constants.
