Judging method for cross section of photonuclear reaction, nucleus transmutation method and germanium detector

A spectrum of predetermined white gamma ray fluxes is measured at a predetermined resolving power and irradiated to a specific nucleus. The spectrum of permeated gamma ray fluxes after the irradiation is successively measured at a predetermined resolving power. In this case, only the component absorbed to the nucleus by the photonuclear reaction among the irradiated gamma rays is exhibited as a difference, on the other hand, since a cross section of the photonuclear reaction is substantially in proportion to the probability of the absorption of the gamma rays, it is judged that the cross section of the photonuclear reaction reaches maximum at the energy level at which the difference appears as a peak. In addition, if fluxes of monochromatic gamma rays are irradiated to a specific nucleus, the photonuclear reaction is promoted to improve conversion efficiency. On the other hand, since a plurality of germanium detectors are connected in the direction of the injection of the gamma ray fluxes so that the entire length of a germanium crystal of the main detection portion is not less than 20cm, the gamma rays at high energy can be detected at a high accuracy. This method is utilized for annihilation treatment of radioactive wastes. (N.H.)