Speaker
Description
In the framework of the EBENE project TU Dresden aims to verify simulations of nuclear dismantling situations. Therefore the activation of concrete and steel samples is experimentally studied. Concrete samples are activated in a neutron reference field with a fluence rate of 2·10⁵ cm⁻² s⁻¹. Depending on the composition and mass of the sample, activities of only a few Becquerel are achieved for certain nuclides of interest. To determine the activity, coincident β- and γ- emissions are detected in separate detectors. This method enables absolute activity determination without requiring knowledge of the individual detector efficiencies. The primary limitation is the low number of detected β-particles, due to their short range in matter. In particular, self-absorption within the sample reduces the number of detectable events significantly. The electron transport is investigated. This reveals opportunities to improve detection efficiency. Therefore, two measures were taken to maximize the detection efficiency of β-particles. First, the sample is structured to increase the area, promoting the generation and emission of β-particles near the surface. Second, the sample is embedded directly within a scintillator matrix and irradiated simultaneously with the scintillator. Experimentally, this led to a 20% increase in detected events compared to a smooth reference sample. Analysis of electron transport in the structured sample reproduces the measured energy deposition distribution and identifies further possibilities for optimization.