INHOMOGENEOUS TRANSMUTATION DETECTOR AND THE METHOD OF ITS EVALUATION

摘要

The inhomegeneous transmutation detector (ITMD) is a new type of neutron detector, the design of which is based on the separation of the process of preparation of an ultra-pure substrate (matrix, carrier) and of the process of preparation of the initial (target) nuclide. The initial nuclide is inserted into a pure substrate in a monoisotopic form using a suitable physical or chemical method, e.g., the method of ion implantation or it is deposited onto a pure substrate in the form of a continuous thin film or a discontinuous microstructure or nanostructure. After the irradiation of the ITMD in the measured radiation field, the detector is evaluated using an analytical method, which is capable to measure concentration depth profiles with high sensitivity (better than ppm), e.g., the method of secondary ion mass spectrometry (SIMS). The neutron fluence and spectrum are determined from the measured profiles. The ITMD can achieve higher sensitivity than the described transmutation detectors up to date and in addition they have lower induced activity after irradiation. The ITMD can be, in principle, applied to other than neutron radiation and to other dosimetric quantities related to fluence. The analytical methods used for its evaluation are selected from the class of methods, which enable accurate measurement of concentration depth profiles with high sensitivity, better than 0.1 %, advantageously the method of secondary ion mass spectrometry (SIMS).