A METHOD FOR NEUTRON TRANSMUTATION DOPING OF SILICON IN RESEARCH REACTORS

The irradiation of silicon for neutron transmutation 'doping (NTD) has become an important item in the industrial utilization of research re actors. This utilization is in fact an important technique in the elec tronic industry as it is used in the production of thyristors, diodes, and integrated circuits. This paper presents a method for silicon dop ing by irradiation in research reactors. The proposed method justifies the required homogeneity of phosphorus doped atoms and results in obt aining a final product with the specified homogeneous electrical resis tivity. The method does not require a mechanism for rotating the silic on ingots during irradiation, and does not require the introduction of absorber material to flatten the neutron flux in the longitudinal dir ection of irradiated samples. The present work introduces also a metho d for optimization of the activation condition based on the use of a p artial graphite reflector surrounding the irradiation channels for NTD of silicon in the reactor.