Dissemination and visualisation of reference decay data from Decay Data Evaluation Project (DDEP)

Abstract

Abstract. As a primary laboratory in the field of ionising radiation metrology, the Laboratoire National Henri Becquerel (LNE-LNHB), CEA Saclay, is involved in measurements, evaluations and dissemination of radioactive decay data.Data measurements undertaken by various laboratories are evaluated by an international commission of experts (Decay Data Evaluation Project) coordinated by LNHB staff in order to establish a set of recommended decay scheme data.New nuclide evaluations are regularly added to our website, the NUCLÉIDE database, published in the BIPM-5 Monographie series and uploaded to our web application LARAWEB, a dedicated tool for alpha and gamma spectrometry. The Mini Table of Radionuclides is produced from time-to-time with data extracted from our database.Various publications are described, along with new search criteria and decay scheme visualisation in LARAWEB.

Call of duty: recommissioning an old HPGe detector

“…A custom collimator, built out of four (5 cm × 10 cm × 10 cm) lead bricks, was put together on the platform, as close as possible to the HPGe end cap, in such a way as to shape a (3 mm × 3 mm)-wide collimation channel parallel to the Z-axis. A 134 Cs point-like calibration source (𝑡 1/2 = 2.0644( 14) a [23]) of known activity (≈ 3 kBq at the time of the measurements) was secured in place behind the collimator, exactly at the center of the collimating channel. As the platform moved to a new (X, Y) position, the collimator channel allowed the source to irradiate a limited area of the detector (hereforth called "pixel").…”

“…Each pixel position could be determined precisely with the help of an alignment laser equipped with a self-calibrating level and mounted at a fixed distant position of about 1.5 m from the detector's end cap (see figure 4). In total, 710 pixels were irradiated, covering more than the full end cap area of the aluminum enclosure, each for a duration of 600 s. From the yields of the 604.7 keV (I% = 97.63%) and 795.9 keV (I% = 85.47%) 134 Cs photopeaks [23] the absorption by the crystal volume behind each irradiated pixel was deduced. The information of the absorption was coupled to the 2D irradiation pattern to reconstruct a 3D model of the crystal.…”

Development and characterization of a mobile γ spectrometer and its field deployment for in situ radioactivity measurements

“…where Ν meas is the measured counting rate of the detector for a particular γ-ray photopeak of energy E, corrected for dead time (less that 0.1% throughout the measurements); N o is the γ-ray emission rate from the source, and P γ is the relative emission probability of a particular γ-ray with energy E. Uncertainties include the statistical error from the counting rate, the uncertainty of P γ found in evaluated nuclear databases (Dulieu et al 2017), and a 3% relative error in the initial activity of the calibration sources, as provided by the manufacturer. Experimental data points are plotted as a function of energy to extract the absolute efficiency of the detector (Fig.…”