Experimental determination of L

International audienceThe fluorescence yields are useful X‐ray atomic fundamental parameters for X‐ray spectrometric purposes but suffer from large tabulated uncertainties, and this is the first time to our knowledge that all three subshell parameters are measured together. We determined the three L partial fluorescence yields and the associated Coster‐Kronig transition probabilities of gadolinium, by selectively ionizing the three L subshells with a tunable monochromatic photon beam. We found ω 1 = 0.099(3) , ω 2 = 0.162(4) , and ω 3 = 0.159(3) that are in good agreement with tabulated values, but our derived uncertainties are significantly reduced

COLEGRAM, a exible user-friendly software for processing of ionizing radiation spectra

International audienceCOLEGRAM is a freely available spectrometry software dedicated to the study of ionizing radiation spectra. It can handle alpha, beta, gamma and X-ray spectra, proposing twenty-eight specific peak shapes in order to fit complex spectra using the non-linear least-squares fitting method. Different optimization cost functions can be used to perform the mathematical adjustment, which is guided by a user-friendly interface. COLEGRAM is also able to perform batch processing on a large number of spectra copying fitted peak information, based on a predefined model. General characteristics of the code and typical application examples are given to illustrate its potential

Metrology of thin layer deposition with combined XRR-GIXRF analysis at SOLEIL

International audienceA new instrument called CASTOR is operated at the SOLEIL synchrotron facility and is dedicated to the characterization of thin films with thicknesses in the nanometer range. The instrument can combine X-ray reflectivity (XRR) measurements with fluorescence (XRF) acquisitions and especially total reflection X-ray fluorescence (TXRF) related techniques such as grazing incidence XRF (GIXRF). The instrument is now routinely installed on the hard X-ray branch of the Metrology beamline and reproducibility is studied as well as reference-free GIXRF analysis. Some representative examples are given to illustrate the capabilities of the setup and of the analysis

Correction to the recommended γ-ray emission intensity of the 255.13 keV photons in the decay of 113 Sn

International audienceThe authors provide corrected measured values of the relative γ-ray emission intensity of the 255.13keV photons from the decay of (113)Sn. Consequently, new recommended values of the evaluated relative and absolute γ-ray emission intensity of the 255.13keV photons following the decay of (113)Sn are proposed

Primary calibration of photodiodes with monochromatic X‐ray beams using an electrical‐substitution radiometer

International audienceThe electrical-substitution cryogenic detector BOLometer for Use in the range of X-rays (BOLUX), which was developed some years ago at CEA/DAM, has been set up and restarted now at LNHB. It has been used for the primary measurement of the intensity (total energy per unit time) of monochromatic synchrotron beams in the energy range from 3 to 30 keV. These well-determined photon beams have been employed for the efficiency calibration of two photodiodes in terms of current induced per unit optical power at different photon energies. In a final step, we explored the possibility to use these primary calibrated photodiodes to determine the efficiency curve of an energy dispersive spectrometer based on a semiconductor detector (Silicon Drift Detector) using less intense monochromatic photon fluxes. The characteristics of the radiometer BOLUX and its principle of operation are described, and the measurements carried out at the synchrotron beamline are presented, including the determination of the beams' intensities, the direct calibration of photodiodes with respect to BOLUX and the use of one of those photodiodes as a standard transfer for the calibration of the SDD

Radionuclide-free efficiency calibration of an HPGe detector using monochromatic photon beams measured with a cryogenic radiometer

International audienceThe efficiency calibration of spectrometers is traditionally based on the measurement of radioactive sources calibrated in activity and whose emission intensities are known. However, in the energy range below 60 keV, there is a lack of reliable tabulated emission intensities and some inconsistencies have been highlighted. Furthermore, if one aims to improve the measurement of emission probabilities, this approach implies the use of the same parameters that one intends to measure. The solution to these limitations is the use of photon fluxes whose intensity has been determined in an absolute way by another technique. Here we present the calibration of a high-purity germanium (HPGe) detector in the energy range from 3 keV to 60 keV through a procedure that involves the following sequence of steps:First, the intensity of a monochromatic photon beam was measured by means of a cryogenic electrical-substitution radiometer BOLUX (BOLometer for Use in the field of X-rays) . Cryogenic detectors are based on the measurement of the temperature rise experienced by an absorber when the radiation interacts with it. In particular, in electrical-substitution radiometers, the amount of incident energy is determined by finding the electrical power that must be dissipated in the material to get the same temperature increase than that obtained during the photonic heating. Second, these well-determined photon beams have been employed for the calibration of different photodiodes in terms of current induced per unit optical power (efficiency) at different photon energies. Finally, for each energy step, the efficiency calibration of an energy-dispersive spectrometer based on an HPGe detector was obtained by comparison with the primarily-calibrated photodiodes.The calibration measurements were performed at two different beamlines (Métrologie and PUMA) of the SOLEIL synchrotron facility, and different photodiodes were used to cover the energy range of interest. The experimental approach and efficiency results will be detailed.The final application of this study is the use of the radionuclide-free calibrated spectrometer to determine new values of absolute X-ray emission intensities for radionuclides, starting with 109Cd and 152Eu.[1] Applied Radiation and Isotopes, Volume 134, April 2018, Pages 131-136 [2] Presented at EXRS2022, submitted to X-Ray Spectrometr

Standardization of xenon-127 and measurement of photon emission intensities

International audienceXenon-127 was standardized by internal gas counting using three proportional counters in a differential arrangement to eliminate edge effects. The detection efficiency of the proportional counters was calculated by considering the cascade of events following the electron capture and associated gamma transitions. Activity per unit volume was measured with 0.7% relative standard uncertainty. Gamma-ray spectrometry was performed and absolute photon emission intensities were derived. This study shows that (127)Xe could be a surrogate for (133)Xe for the calibration of remote radio-xenon monitoring stations

Estimating the uncertainties in combined GIXRF-XRR for the characterization of innovative materials

International audienceThe combination of XRR and GIXRF is used for the characterization of thin films and multilayered materials, since both techniques use similar measuring and data analysis procedures. Since XRR is more sensitive to the electronic density, it is used to determine the thickness and roughness of thin layers, and GIXRF, being more sensitive to the elemental density, provides information on the depth distribution of the elements. Therefore, combining these two techniques leads to more accurate characterization than with a single technique [1]. However, there is a major difficulty to determine the associated uncertainties, due to the large number of parameters and more specifically, to the combination of the two methods with dramatically different dynamic ranges.The objective in this work is to quantify the uncertainties on the parameters of the optimized structure (thicknesses, roughness, density, etc.). Since repeating the combined measurements is a time-consuming process, we propose a recursive method for the estimation of the uncertainties of the data from the GIXRF-XRR analysis, based on the Bootstrap statistical method [2]. This method allows the generation of random uniform weights, between 0 and 1, that are multiplied by the absolute difference between the experimental and theoretical values. The application of these weights results in new sets of calculated values and the uncertainties on the optimized parameters can be derived.This method was applied to combined GIXRF-XRR measurements which where carried out in the goniometer CASTOR (Chamber of Spectrometric Analysis in Transmission or in Reflection) at the hard X-ray Metrology beamline of the synchrotron SOLEIL facility [3]. One of the studied samples is an amorphous chalcogenide GeSbTe (germanium, antimony and tellurium) thin film. In order to excite the Kα-line of germanium and the Lα-lines of tellurium and antimony, the GIXRF data were acquired at an excitation energy of 11.5 keV, while the XRR measurements were carried out at an excitation energy of 8 keV, in order to benefit from the highest photon flux.First, XRR data were analyzed with IMD [4] to obtain an estimation of the structural composition and then GIXRF spectra were fitted with COLEGRAM [5] to derive the intensity of the fluorescence X-ray lines. Finally, starting with the model obtained with IMD and the fitted fluorescence data, the GIXRF-XRR analysis was performed using in-house software to derive the sample structure and associated uncertainties

Quantitative element analysis with an energy dispersive X-ray fluorescence instrument equipped with a highly oriented pyrolytic graphite filter

International audienceWe present an energy-dispersive X-ray fluorescence (EDXRF) instrumentation mainly intended for the quantitative analysis of actinides based on their intense L X-ray lines. The experimental setup is equipped with a highly oriented pyrolytic graphite (HOPG) optic as a bandpass filter placed between a sample and a detection system. In such an arrangement, it modifies the spectral distribution of the fluorescence radiation and allows recording of a spectrum in the energy range from 10 keV to 18 keV, while suppressing parts considered to be useless. In order to perform accurate quantitative analysis of the recorded spectra, the classical quantification algorithm based on the fundamental parameters must be adapted to take into account the effect of the HOPG optic on the measured intensities. This requires to determine the transmission function of the HOPG filter and implement it in the algorithm. The validity of this approach is checked in different application examples

Combien de photons ?

International audienceLa connaissance du flux de photons X incidents est nécessaire pour les analyses quantitatives. C’est aussi une donnée primordiale quand on souhaite connaître la dose reçue par un échantillon biologique. Le LNE-LNHB, laboratoire primaire français pour la métrologie des rayonnements ionisants, a parmi ses missions celle d’étalonner sources et détecteurs. Le LNE-LNHB étalonne en rendement des détecteurs (photodiodes, SDD) pour ses propres besoins d’analyses quantitatives et sans référence (analyse combinée XRR-GIXRF). Le LNE-LNHB a repris l’activité bolomètre du CEA-DAM en 2020. Ce bolomètre (BOLUX) permet de mesurer la puissance optique reçue