Grégoire Chene

Precision measurement of radioactivity in gamma-rays spectrometry using two HPGe detectors (BEGe-6530 and GC0818-7600SL models) comparison techniques: Application to the soil measurement

Graphical abstract

Optimal measurement counting time and statistics in gamma spectrometry analysis: The time balance

The optimal measurement counting time for gamma-ray spectrometry analysis using HPGe detectors was determined in our laboratory by comparing twelve hours measurement counting time at day and twelve hours measurement counting time at night. The day spectrum does not fully cover the night spectrum for the same sample. It is observed that the perturbation come to the sun-light. After several investigations became clearer: to remove all effects of radiation from outside (earth, the sun, and universe) our system, it is necessary to measure the background for 24, 48 or 72 hours. In the same way, the samples have to be measured for 24, 48 or 72 hours to be safe to be purified the measurement (equality of day and night measurement). It is also possible to not use the background of the winter in summer. Depend on to the energy of radionuclide we seek, it is clear that the most important steps of a gamma spectrometry measurement are the preparation of the sample and the calibration of the detector.At the request of...

Inter-technique comparison of PIXE and XRF for lake sediments

In this paper we describe a validation procedure for the chemical analysis of major elements and some minor elements such as Sr, Cr, Ni, Zn and Zr in heterogeneous geological sediments. The procedure applies two distinct techniques (PIXE and XRF) for the analysis of sediments. In this work an inter-technique comparison of heterogeneous lacustrine sediments from Amik Lake in the vicinity of the Roman city of Antioch (SE, Turkey) was carried out. Dried raw samples and samples with linking powder added were analyzed using PIXE performed at the “Arkeo” beamline of the University of Liege AVF cyclotron and XRF (University of Liege). The aim of this work was to compare PIXE and XRF analysis with set-ups routinely in use in the two laboratories. The purpose was also to determine the best combination of techniques and sample preparation protocols to be applied for heterogeneous sediments and the main elements of interest for each specific technique. The results are in agreement among the two techniques, with discrepancies concerning lighter and minor elements. These differences are mainly related to the texture of the sediments and the intrinsic features of the XRF and PIXE techniques. Major and selected minor elements are sensitive to the grain size and porosity of the samples. However, the accuracy of both XRF and PIXE requires the reduction of the grain size or addition of a linking powder to the sediments to fill the voids in order to increase the intensities of both lighter and minor elements. The results demonstrate the critical importance of sample treatment prior to analysis as well as the necessity of several measurement points and replicates to ensure the accuracy of PIXE results.