Radiation monitoring on replacement work of the mercury target vessel in J-PARC

Masuyama, Koichi; Sato, Koichi ; Yoshino, Koji; Tajima, Takahiro*; Seki, Kazunari; Kasugai, Yoshimi  ; Miyamoto, Yukihiro  

The mercury target vessel used in the Materials and Life Science Experimental Facility (MLF) in the Japan Accelerator Research Complex (J-PARC) needs to be replaced periodically. The replacement work, which is conducted in the hot cell, associates with release of radioactive materials produced via spallation reactions between protons and mercury. Therefore we monitored radioactivity of dust and air samples in the hot cell. By the monitoring, we newly found peculiar phenomena on the behavior of radioactive products, which is important for radiation control. In this work, we will show the monitoring data and the new observation.