Induced radioactivities in concrete constituents irradiated by high-energy particles

The powdered concrete constituents of magnetite ore, pyrites ore, marble, gravel and Portland cement were prepared and irradiated by 12- GeV protons and secondary particles at the slow extracted beam line of the National Laboratory for High Energy Physics ( KEK ) 12- GeV proton synchrotron. The saturated activities for individual nuclides produced were calculated, and the time variation of photon exposure rate due to the residual activities was also evaluated for each sample. The exposure rates ranked in the following order: magnetite ore greater than pyrites ore greater than gravel greater than or equal to cement greater than marble. The levels of photon exposure rates from heavy, ordinary and marble concretes were also estimated on the basis of the results obtained for each constituent. It is suggested that the use of marble concrete in the inside wall of accelerator tunnels can reduce considerably the exposure to the accelerator maintenance workers, compared with heavy and ordinary concretes commonly used.