Calibration of the irradiation channel DBVK at BER-II reactor and feasibility of applying the k 0 -method at this device

This work is about k 0 -INAA using unstable neutron flux for sample irradiation. Due to slow transport, each irradiation in the channel DBVK consists of three phases: stable irradiation at the final position, and two additional irradiations during travelling by exposure to an increasing neutron flux in the delivery course and to a decreasing neutron flux in the fetch course. In this work, the neutron flux distribution along this channel was calibrated and the neutron flux variation with irradiation time was calculated, making it possible to evaluate activity growth during a complete irradiation period. The feasibility of the k 0 -method was checked by analyses of four SRM-materials and three multi-element standards at three DBVK-positions. An accuracy of better than ±10% was found for nearly all determined elements in each determination.