Nondestructive test device and test method for radiation contaminated material

In a nondestructive test device, a collimator equipped with a shielding member for restricting the number of radiation beams irradiated from a material to be tested is disposed in front of a Ge detector, and proton sources are disposed to the outside of the field of view of the opening of the collimator equipped with a shielding member to restrict the irradiation region within a range of the field of view of the Ge detector. 0.511MeV annihilated gamma rays generated in the collimator equipped with the shielding member are absorbed to the shielding member and do not reach the Ge detector. Accordingly, the annihilated gamma rays do not overlaid with the input of the detector to provide a high S/N ratio. Further, the signals from the Ge detector are digitalized by a multi channel analyzer by way of the preamplifier and a linear amplifier, and parameters having a shape of photoelectron peak of the annihilated gamma rays represented by an S parameter are calculated. Then, even if the material to be tested is radiation-contaminated or activated, an operator's exposure can be reduced thereby capable of conducting inspection safely and at a high accuracy, for example, in periodical inspection. (N.H.)