Radiation countermeasures in high intensity beam lines

In the construction of high energy accelerators for high intensity proton beam, the rational safety design is desirable for radiation countermeasures so that the construction cost does not rise too high. At present, the conceptual design of a high intensity proton accelerator called large hadron project is carried out, and as a part of its facility design, radiation countermeasures and radiation control are investigated. In this report, a part of the radiation countermeasures taken in consideration when the north counter hall which is used for experimental research by leading proton beam from the 12 GeV proton accelerator in National Laboratory for High Energy Physics was constructed is summarized. Routine radiation control is carried out as spatial control, coming in and out control, radioactive substance control and radiation exposure control. The radiation control at the north counter hall and the subjects for hereafter, especially the problem of radioactivation are reported. (K.I.)