Measurements of radionuclides induced in the accelerator structure of the KEK-PS

Radionuclides induced in accelerator structures were measured during each long shut-down by using a pure Ge detector and a portable multichannel pulse height analyzer. Variation in the nuclide composition for various points in the accelerator tunnel was investigated. The decay of the exposure rate was calculated using the measured nuclide composition. Radionuclide measurements of the vacuum chamber removed from the accelerator were also performed. The relation between the variation of the residual exposure rate and that of the nuclide composition was examined and it was found that the proportion of 48V, 54Mn and 56Co corresponds to variation in the beam loss pattern.